The number is not what your house is worth
The most common way this goes wrong is not carelessness. It is using a sensible-looking number that measures the wrong thing.
Home insurance covers the building. It does not cover the land under it. So the market value of the property — which is mostly a statement about location and about the property market — is not the measure. California's insurance department is direct about it: the limit should reflect “the cost of labor and materials necessary to rebuild the dwelling, not fluctuations in the real estate market”.
Depending on where you are, replacement cost can sit well above market value or well below it. In an expensive market with modest houses, rebuild cost is often far lower than sale price. In a cheap market with a large or unusual house, it is often far higher. Neither case tells you anything about the other, and the coincidence when the two numbers are close is exactly that.
| Figure | What it is | Why it is not your dwelling limit |
|---|---|---|
| Replacement cost | “The amount it would take to replace or rebuild your home or repair damage with materials of similar kind and quality, without deducting for depreciation” | This one is. It is the cost of labor and materials to put the building back |
| Market value | “A real estate term describing the current value of your home if you were to sell it, including the price of the land” | It includes the land, which the policy does not cover, and it moves with the property market rather than with construction costs. It can sit either side of replacement cost |
| Actual cash value | “The value of your property when it is damaged or destroyed. This is usually figured out by taking the replacement cost and subtracting depreciation.” | It is a settlement basis, not an amount of coverage. It describes how a claim is paid, not how much coverage you bought |
| Assessed value or purchase price | What a taxing authority assigned, or what you paid | Neither has any necessary relationship to what a builder would charge to rebuild the structure today |
The floor, and why it matters on small claims
Here is the part that is usually reported wrong.
Replacement cost settlement is conditional. Wisconsin's insurance regulator states the condition plainly: “To qualify for full replacement cost coverage, the building is required to be insured at 80% to 90% of the replacement cost.” Not 80% flat — a range, and which end applies is a feature of your policy.
And the consequence of falling below it is not confined to a total loss. The same guide says that where coverage falls below the threshold, the insurer “is not obligated to pay the total amount of loss, even if it's a small loss” — the guide's own sentence opens “If you purchase an amount of coverage less than 80% to 90% of the amount required to have replacement coverage”, which is the condition that makes it bite. NAIC puts the mechanism the same way: below 80% of full replacement cost, an insurer “may reduce the amount that it will pay on a claim”.
So the exposure is not the dramatic one people imagine. It reaches the ordinary claims that make up almost all claims — a kitchen fire, a burst pipe, a section of roof. Being under-insured is a discount on every building settlement, not an insurance policy with a small hole at the far end.
Two limits on that sentence. This is a Coverage A and B loss-settlement condition: it does not discount a contents or a liability claim. And the arithmetic: neither regulator spells it out, and the version in the table above — your limit divided by the required percentage of replacement cost, with actual cash value as a floor beneath it — is our reading of the standard condition, which we have not read in any form. Your own policy’s Loss Settlement condition is what governs, and it is worth reading before you rely on any number on this page.
| The common version | What the regulators actually say |
|---|---|
| “You have to insure to 80%” | Wisconsin's guide: “To qualify for full replacement cost coverage, the building is required to be insured at 80% to 90% of the replacement cost.” It is a range set by the policy, not a single national threshold |
| “It only matters if the house burns down” | Wisconsin's guide, on falling below the threshold: your insurer “is not obligated to pay the total amount of loss, even if it's a small loss”. It bites on partial claims — which are the claims people actually make |
| “They just pay a bit less” | NAIC: “If it drops below 80% of the full replacement cost of your home, your insurance company may reduce the amount that it will pay on a claim.” How much less is not stated by either guide, and “proportional to how far below the threshold you have fallen” — the usual formulation — reads two ways that give different money. The arithmetic, stated so you can check it: the recovery is your limit divided by (the required percentage × replacement cost), applied to the loss. Replacement cost $400,000, an 80% requirement, a $240,000 limit and a $40,000 loss gives 240,000 ÷ 320,000 = 0.75, so $30,000 — not the $32,000 you get if you read “how far below” as measured against replacement cost instead. And there is a floor: the standard condition pays the greater of that figure or actual cash value, so the proportional result is not always what you receive. This is our reading of the standard condition and we have not verified it against a form. Neither guide we cite gives the formula, and we have not read a Loss Settlement condition in any form — our raw readings of the two ISO editions cover Section I Conditions only in part, and not that provision. Your own policy's Loss Settlement condition is what governs. It is also a building condition — it does not discount a contents claim |
| “I set it correctly when I bought the policy” | Construction costs move. A limit that was right at purchase can drift below the threshold without you doing anything, which is what inflation-guard endorsements exist to counter — and they are an estimate, not a guarantee |
Dropped, denied, or holding a notice you do not understand? Call us. We will read the letter with you, tell you which clock you are on and what your state requires your insurer to do — then put you in touch with a licensed agent who can quote you and write the policy.
Call (866) 754-7910Monday to Friday, 9am to 5pm ET (6am to 2pm PT). We are not an insurance agency and we do not sell policies. Call and we will help you make sense of what you have been sent — then put you in touch with a licensed agent — the one person who can actually quote you and write a policy. We hold no insurance license, so we cannot quote you, recommend an insurer, or advise you on your own policy.Extended, guaranteed, and the difference between them
These two terms are used almost interchangeably in marketing material and they are not interchangeable.
Extended replacement cost pays “your policy limits, plus a certain percentage above those limits”. It is a buffer. The question to ask is what the percentage is — and to notice that because it is a percentage of your limit, an understated limit produces an understated buffer. The error compounds rather than being absorbed.
Guaranteed replacement cost is a stronger promise. California's department states that a policy “cannot be sold as a ‘guaranteed replacement cost’ policy unless it will pay to completely rebuild the home regardless of the coverage limit”. That is not merely the department's view: it is codified at Cal. Ins. Code § 10102(e), so a Californian holding a policy sold as guaranteed replacement cost has a statute to point at, not a brochure — and the guide itself gives no section number, which is why it is so often reported as departmental opinion. Where it is available it removes the insure-to-value problem entirely. It is not widely available, and it is least available where rebuild costs are most volatile.
| Option | What it pays | The catch |
|---|---|---|
| Replacement cost to the limit | Up to your Coverage A figure, without deduction for depreciation | If the rebuild costs more than the limit, the excess is yours. The limit is doing all the work |
| Extended replacement cost | “Your policy limits, plus a certain percentage above those limits” | A buffer, not a blank check. Ask what the percentage is — and note it is a percentage of your limit, so an understated limit understates the buffer too |
| Guaranteed replacement cost | California's guide states that a policy “cannot be sold as a ‘guaranteed replacement cost’ policy unless it will pay to completely rebuild the home regardless of the coverage limit”. The guide gives no section number, but the rule is codified: Cal. Ins. Code § 10102(e) bars issuing such a policy as guaranteed replacement cost if it carries “any maximum limitation of coverage”, and (f) applies the same bar on renewal | It is not widely available, and availability has tightened in higher-hazard areas. Where it is offered, read whether it is truly unlimited or extended coverage using the word loosely |
| Ordinance or law coverage | The cost of meeting current building codes during a repair or rebuild | Separate from all of the above. Without it, an insurer “may not pay for changes you may need to make to the structure of your home to bring it up to current building codes” — a real exposure on an older house |
Why we will not give you a cost per square foot
You will find a great many pages offering one, and they are the reason so many dwelling limits are wrong.
Rebuild cost per square foot varies by local labor market, by construction type, by finish level, by roof type, by how difficult the site is to work on, and by the year. A national average across all of that is not an average of anything you could build. Worse, it is usually quoted without a date, so it goes on being repeated after it has stopped being true.
What is worth doing instead is unglamorous: get your insurer's replacement-cost estimate, ask what inputs it used, and check those. The estimator is generally reasonable; the inputs are frequently wrong, and they are the part you can actually correct.
| Coverage | Usual relationship to Coverage A |
|---|---|
| B — Other structures | Normally 10% — California's department says Coverage B is “normally limited to 10% of the coverage A limit” and that “you may purchase more coverage for an additional premium”. A default you can raise, not a cap you must buy your way past. “10%, unless additional premium is paid” is the common phrasing, and it turns an option into a condition |
| C — Personal property | 50% is the standard relationship Wisconsin's guide gives |
| D — Loss of use | Normally 20% |
| Personal property away from the premises | Wisconsin's guide does give a figure: its “Typical Coverages” table lists Unscheduled Personal Property off Premises at “10% of personal property” — ten per cent of the contents limit, not of the dwelling limit. Note the scope: that table is presented for Homeowners Form 2, so it is a form-specific illustration rather than a universal rule. Ask what yours is |
Arriving at a number
Nothing here is advice about your property and we have not seen it. This is the sequence the definitions above imply.
| Step | What to do | Why |
|---|---|---|
| 1 | Stop using the market value, the purchase price and the tax assessment | None of them measures labor and materials, and all three include or exclude the land in ways that have nothing to do with rebuilding |
| 2 | Ask your insurer for its replacement-cost estimate and the inputs | Most carriers run an estimator. The inputs — square footage, construction type, roof type, finishes — are where the errors are, and they are yours to correct |
| 3 | Check the finishes, not just the footprint | Two houses of identical size rebuild for very different amounts. Custom cabinetry, stone, plaster, tile roofs and non-standard windows are the usual gaps |
| 4 | Add ordinance or law if the house is older | Rebuilding to today's code is not the same job as rebuilding what was there |
| 5 | Ask where you sit against the insure-to-value threshold | It is the difference between full replacement cost settlement and a proportional reduction on every building claim, including small ones. It is a Coverage A and B loss-settlement condition — it does not discount a contents or a liability claim, which “every claim” would wrongly suggest |
| 6 | Re-check after any renovation, and periodically without one | An addition changes the rebuild cost immediately. Construction-cost movement changes it quietly |
Corrections to this page (6)
We publish these rather than editing quietly. Our corrections policy explains how we handle errors.
- — Three reader-facing surfaces — the answer block, a takeaway and an FAQ — described the insure-to-value reduction as a discount on ordinary claims, with no scope at all. We corrected this on 27 August: it is a building loss-settlement condition and does not discount a contents claim, and an actual-cash-value floor sits beneath the reduced figure. The correction reached the table, the body section and step 5, and none of the three sentences a reader quotes. The FAQ version is also emitted as structured data, so it was the version most likely to be extracted and shown stripped of the page. A reader making a contents claim was told their belongings settlement would be cut when our own tables say it will not.
- — The same FAQ stated the proportional formula as flat fact. Our table marks it our reading of the standard condition, unverified against a policy form, and our own retracted-wording registry lists the phrasing. It is now labeled in the FAQ too.
- — Our own correction never reached the prose. On 24 August we published a correction establishing that California's guaranteed-replacement-cost rule is statutory — Cal. Ins. Code § 10102(e) — and not merely the department's view. That correction was applied to the table and the methodology. The section a reader actually reads went on saying the department stated it “without a statutory citation behind it” for three more days. A Californian mis-sold a “guaranteed replacement cost” policy has a statute to point at, and this page told them they had a brochure.
- — We printed Coverage B as “10%, unless additional premium is paid” — the wording our own declarations-page article had published a correction for on 23 August, in the same words, from the same source. California's department says Coverage B is “normally limited to 10% of the coverage A limit” and that “you may purchase more coverage for an additional premium”. That is a default you can raise, not a cap you must buy past.
- — We described the insure-to-value penalty and never gave the arithmetic. We said the reduction was “proportional to how far below the threshold you have fallen”, which reads two ways that differ by real money: on a $400,000 rebuild with an 80% requirement, a $240,000 limit and a $40,000 loss, one reading pays $30,000 and the other $32,000. The formula, the worked example, the actual-cash-value floor beneath it, and the fact that we have not verified it against a form are all now on the page. We also said the reduction applies to “every claim”; it is a building loss-settlement condition and does not discount a contents claim.
- — We retracted the 10 percent figure for belongings away from the premises, saying neither regulator guide stated one. That retraction was wrong: Wisconsin's guide gives it in its Typical Coverages table as “10% of personal property”, for Homeowners Form 2. We had searched the prose and not the tables. The figure is restored with that scope.
How we researched this
The definitions of replacement cost, market value and actual cash value, and the insure-to-value requirement, are quoted from the Wisconsin Office of the Commissioner of Insurance's Consumer's Guide to Homeowners Insurance, PI-015, revision 07/2026. One caution about that guide: its revision code is 07/2026 but its worked example still insures a dwelling for $60,000, so the code does not establish that every sentence in it was rewritten. The definitions we quote from it are stable ones. The parallel statement of the 80 percent threshold is from NAIC's A Consumer's Guide to Home Insurance, 2022. We quote both because they differ: Wisconsin states a range of 80 to 90 percent and NAIC states 80 percent, and reporting either one alone as the rule would be a false precision.
The dwelling-limit framing, the extended and guaranteed replacement cost definitions and the ordinance or law point are from the California Department of Insurance's Residential Insurance: Homeowners and Renters guide, revised May 2024. The guaranteed replacement cost sentence is quoted rather than paraphrased because what a policy may be called is the part that protects a buyer.
Correction, 24 August 2026. This page previously added that the guide “cites no statute” for that rule and told readers to treat it as the department's statement rather than something they could look up. It is statutory. Cal. Ins. Code § 10102(e) provides that a residential property policy “shall not be initially issued as guaranteed replacement cost coverage if it contains any maximum limitation of coverage based on any set dollar limits, percentage amounts, construction cost limits, indexing, or any other preset maximum limitation for covered damage to the insured dwelling”, and (f) imposes the same bar on renewal. We downgraded a statutory prohibition to an opinion because the guide we were reading did not carry the citation — the absence of a citation in one document is not evidence that no statute exists.
Correction, 23 August 2026, itself corrected on 25 August 2026. The derived-coverages table gave 10 percent of the personal property limit for belongings away from the premises. On 23 August we retracted that figure as an industry convention we had absorbed and printed as though sourced. The retraction was wrong and the original figure was right. Wisconsin's guide prints it in its “Typical Coverages” table as “Unscheduled Personal Property off Premises — 10% of personal property”. We had searched the guide's prose and not its tables. The figure is restored, with the scope we should have carried the first time: that table is presented for Homeowners Form 2. This is the second retraction on this site to need retracting, and the rule stands — a retraction is a published claim and needs the same proof as the thing it retracts. The proportionality of the insure-to-value reduction, and the legal status of the guaranteed replacement cost rule, are now marked as our reading rather than the regulators'.
The percentage relationships in the derived-coverages table are the standard defaults those guides describe, not universal rules; several are adjustable for additional premium and your own declarations page governs. Each is stated with what it is a percentage of.
There is deliberately no cost-per-square-foot figure anywhere on this page, and no dollar estimate of any rebuild. We have no defensible source for a national one, the figures that circulate are typically undated, and a number of that kind presented confidently is how dwelling limits get set wrong in the first place. Nothing here is advice about your property. If you find an error, our corrections policy explains how we handle it.
Sources
Every passage this page puts in quotation marks, with the document it came from, the part of that document, and the date we read it. 16 quotations from 4 documents. Follow the links and check us. Statutes are amended and pages move; if one of these is wrong or dead, our corrections policy says how we handle it.
Wisconsin OCI, Consumer's Guide to Homeowners Insurance, PI-015 R 07/2026 — https://oci.wi.gov/Documents/Consumers/PI-015.pdf
Unscheduled Personal Property off Premises
Wisconsin OCI, Consumer's Guide to Homeowners Insurance, PI-015 R 07/2026 — the row label in the 'Typical Coverages' table, which gives it as '10% of personal property'. Registered 25 Aug 2026 after this page RETRACTED that figure on the ground that neither guide stated one: we had searched the guide's prose and never its tables. The table is presented for Homeowners Form 2, so the figure is form-specific Retrieved 25 August 2026.
Market value is a real estate term describing the current value of your home if you were to sell it, including the price of the land
Wisconsin OCI, Consumer's Guide to Homeowners Insurance, PI-015 R 07/2026 — 'Buying Enough Coverage' Retrieved 24 August 2026.
Replacement cost is the amount it would take to replace or rebuild your home or repair damage with materials of similar kind and quality, without deducting for depreciation
Wisconsin OCI, Consumer's Guide to Homeowners Insurance, PI-015 R 07/2026 — 'Buying Enough Coverage' Retrieved 24 August 2026.
Actual cash value is the value of your property when it is damaged or destroyed.
Wisconsin OCI, Consumer's Guide to Homeowners Insurance, PI-015 R 07/2026 — 'Buying Enough Coverage'. The page once joined this and the next sentence with an em dash, deleting 'This is'; both sentences are now quoted as the guide prints them Retrieved 24 August 2026.
This is usually figured out by taking the replacement cost and subtracting depreciation.
Wisconsin OCI, Consumer's Guide to Homeowners Insurance, PI-015 R 07/2026 — 'Buying Enough Coverage', second sentence Retrieved 24 August 2026.
To qualify for full replacement cost coverage, the building is required to be insured at 80% to 90% of the replacement cost.
Wisconsin OCI, Consumer's Guide to Homeowners Insurance, PI-015 R 07/2026 — 'Buying Enough Coverage' Retrieved 24 August 2026.
If you purchase an amount of coverage less than 80% to 90% of the amount required to have replacement coverage, your insurance company is not obligated to pay the total amount of loss, even if it's a small loss.
Wisconsin OCI, Consumer's Guide to Homeowners Insurance, PI-015 R 07/2026 — 'Buying Enough Coverage', quoted WHOLE. An earlier registry entry began this at 'Your insurance company is not obligated', recapitalized into a freestanding sentence. No such sentence exists in PI-015: the opening clause is the entire condition, and without it the quotation states that an insurer is NEVER obliged to pay a loss in full. That is a conditional inverted into an absolute Retrieved 24 August 2026.
CDI, Residential Insurance: Homeowners and Renters, rev. May 2024 — https://www.insurance.ca.gov/01-consumers/105-type/95-guides/03-res/res-ins-guide.cfm
normally limited to 10% of the coverage A limit
CDI, Residential Insurance: Homeowners and Renters, rev. May 2024 — the Coverage B entry Retrieved 27 August 2026.
you may purchase more coverage for an additional premium
CDI, Residential Insurance: Homeowners and Renters, rev. May 2024 — the Coverage B entry, the sentence immediately following. IT IS THE HALF THAT MAKES IT AN OPTION Retrieved 27 August 2026.
Other types of replacement cost policies will pay your policy limits, plus a certain percentage above those limits.
CDI, Residential Insurance: Homeowners and Renters, rev. May 2024 — 'Will My Policy Completely and Totally Replace My Home If It Is Destroyed?'. CDI does not use the term 'extended replacement cost' Retrieved 24 August 2026.
cannot be sold as a 'guaranteed replacement cost' policy unless it will pay to completely rebuild the home regardless of the coverage limit
CDI, Residential Insurance: Homeowners and Renters, rev. May 2024 — same section Retrieved 24 August 2026.
Unless your policy has this coverage, your insurance company may not pay for changes you may need to make to the structure of your home to bring it up to current building codes
CDI, Residential Insurance: Homeowners and Renters, rev. May 2024 — inside the section headed 'Will My Policy Completely and Totally Replace My Home If It Is Destroyed?'. Quoted from the conditional 'Unless…' onward. An earlier entry began after that clause, which turned a rule about policies LACKING ordinance-or-law coverage into a rule about all policies Retrieved 24 August 2026.
the cost of labor and materials necessary to rebuild the dwelling, not fluctuations in the real estate market
CDI, Residential Insurance: Homeowners and Renters, rev. May 2024 — 'What Limits Should I Set on My Policy' Retrieved 24 August 2026.
NAIC, A Consumer's Guide to Home Insurance (2022) — https://content.naic.org/sites/default/files/publication-hoi-pp-consumer-homeowners.pdf
If it drops below 80% of the full replacement cost of your home, your insurance company may reduce the amount that it will pay on a claim.
NAIC, A Consumer's Guide to Home Insurance (2022) — 'LIMITS OF COVERAGE' Retrieved 24 August 2026.
Cal. Ins. Code § 10102(e) — https://california.public.law/codes/ca_ins_code_section_10102
shall not be initially issued as guaranteed replacement cost coverage if it contains any maximum limitation of coverage based on any set dollar limits, percentage amounts, construction cost limits, indexing, or any other preset maximum limitation for covered damage to the insured dwelling
Cal. Ins. Code § 10102(e) Retrieved 24 August 2026.
any maximum limitation of coverage
Cal. Ins. Code § 10102(e) Retrieved 24 August 2026.
Frequently asked questions
Should my dwelling coverage equal what I paid for the house?
No, and the two figures are not measuring the same thing. The purchase price includes the land, which your policy does not cover, and it reflects the property market rather than construction costs. California's insurance department frames the dwelling limit as the cost of labor and materials to rebuild, not fluctuations in the real estate market. Depending on your area the rebuild cost can be well above or well below what you paid.
What happens if I am under-insured?
Full replacement cost settlement is generally conditional on insuring to a threshold — Wisconsin's regulator describes it as 80 to 90 percent of replacement cost. Below that, your insurer is "not obligated to pay the total amount of loss, even if it's a small loss", and NAIC describes the same mechanism as the insurer reducing what it pays on a claim. It applies to ordinary partial claims and not only to a total loss. Two limits on that, both of which matter. It is a building loss-settlement condition: it does not discount a contents claim. And the reduction is not unlimited — an actual-cash-value floor sits beneath the reduced figure. How the reduction is calculated is our reading of the standard condition; we have not verified the formula against a policy form.
Is the rule 80 percent or 90 percent?
It depends on your policy, which is why we give the range rather than a single figure. Wisconsin's guide states the requirement as 80 to 90 percent of replacement cost, and NAIC's consumer guide uses 80 percent. The number that governs is the one in your own policy's loss settlement condition, and it is a reasonable question to put to your agent — particularly if your limit has not been reviewed for a few years.
What is the difference between extended and guaranteed replacement cost?
Extended replacement cost pays your policy limits plus a certain percentage above them — a buffer of a stated size. Guaranteed replacement cost pays to rebuild regardless of the limit; California's rules do not permit a policy to be sold as guaranteed replacement cost unless it does exactly that. The two are frequently described in similar language and are materially different promises, so it is worth confirming which one is on your policy.
Does inflation guard mean I do not have to think about this?
It helps and it is not a guarantee. An inflation-guard endorsement raises your limit automatically by an index or a set percentage, which counters gradual construction-cost movement. It does not know about your renovation, your new addition, or a local spike in labor costs after a regional catastrophe. It is a reason to review less often, not a reason not to review.
How much does it cost to rebuild per square foot?
We will not give you a number, and we would treat any site that does with suspicion. Rebuild cost per square foot varies by local labor market, construction type, finish level, roof type, site access and year — a national average across all of that is not an average of any house you could actually build, and the figures that circulate are usually undated. Ask your insurer for its replacement-cost estimate and check the inputs it used.
Do I need ordinance or law coverage?
It depends on the age of the house and your local code, but it is worth checking rather than assuming. It covers the cost of meeting current building codes during a repair or rebuild. California's department states that unless your policy has this coverage, your insurer may not pay for changes needed to bring your home up to current codes — and on an older house, rebuilding to today's code is a materially different job from rebuilding what was there.