What is the difference between market value and assessed value?

Market value is what your home would sell for on the open market today. Assessed value is the figure your county records for tax purposes, produced by a mass-appraisal model that weighs many variables at once. The two are related but will rarely match exactly.

Which value is used to calculate my property tax bill?

Your property tax bill is calculated against your assessed value, not your market value. That is why the assessed value on your annual notice is the number worth checking each year, even if you have no plans to sell your home.

Why does assessed value differ from market value?

County assessors value hundreds of thousands of homes at once using a statistical model rather than visiting each property. The model weighs many variables and is accurate in aggregate, but any given home's figure can land above or below what a current sale would show.

Can I challenge my assessed value if it looks too high?

Yes. Every jurisdiction has an annual property tax appeal window where homeowners can challenge the assessed value on their notice. The filing body, deadline, and process vary by county, so the specifics depend on where the property sits.

Market Value vs Assessed Value: What Homeowners Should Know

Market value is what your home would sell for today. Assessed value is what your county records for tax purposes. They are related but not identical.

Large gray shingle-style home with hydrangeas and stone wall

Market value is what your home would sell for on the open market today. Assessed value is the number your county records for tax purposes. The two are related but they are not identical. County assessed value is produced by a mass-appraisal model that weighs many variables at once.

What is market value?

Market value is the price a willing buyer and willing seller would agree to in an arm's length sale. It reflects real conditions in your neighborhood today: what similar homes have sold for, how long listings sit, and what buyers are actually paying. A recent sale is the cleanest signal. Without one, market value is a judgment call based on comparable sales.

What is assessed value?

Assessed value is the number your county assessor places on your home for property tax purposes. The assessor does not visit every property each cycle. Instead, a statistical model weighs many variables across the jurisdiction and produces an estimate for each parcel on the roll. That estimate becomes the assessed value on your notice, and it is what your property tax bill is calculated against.

Why does the difference matter?

Because assessed value is model-generated, it will not match market value exactly. In a rising market, assessed values often lag actual sale prices. In other cases, the model lands high for a specific home even when the neighborhood has not moved. Your tax bill is based on the assessed figure, so that is the number worth checking each year. If it looks off, a property tax appeal is the built-in way to challenge it. FairAppeal reviews assessments at no cost and only charges if an appeal wins. The Fair Appeal review is free. For one concrete example of how an annual cycle works, see our King County reassessment explainer.

Look up if you are overpaying.

Frequently asked questions

What is the difference between market value and assessed value?: Market value is what your home would sell for on the open market today. Assessed value is the figure your county records for tax purposes, produced by a mass-appraisal model that weighs many variables at once. The two are related but will rarely match exactly.
Which value is used to calculate my property tax bill?: Your property tax bill is calculated against your assessed value, not your market value. That is why the assessed value on your annual notice is the number worth checking each year, even if you have no plans to sell your home.
Why does assessed value differ from market value?: County assessors value hundreds of thousands of homes at once using a statistical model rather than visiting each property. The model weighs many variables and is accurate in aggregate, but any given home's figure can land above or below what a current sale would show.
Can I challenge my assessed value if it looks too high?: Yes. Every jurisdiction has an annual property tax appeal window where homeowners can challenge the assessed value on their notice. The filing body, deadline, and process vary by county, so the specifics depend on where the property sits.