Tax Assessed Value vs Market Value: Why They Are Different Numbers
TL;DR
Your tax assessed value and your home's market value are almost never the same number. Market value is what a buyer would pay on the open market. Assessed value is the number the county uses to calculate your tax bill. In many states, assessed value is a percentage of market value (50%, 33%, 10%, depending on the state). In states that assess at 100%, the assessed value may still lag behind or exceed actual market value because assessments are only updated periodically. When your assessed value is higher than the market supports, you are overpaying.
What Is Market Value?
Market value is the price a willing buyer would pay and a willing seller would accept in an arm's-length transaction. It is determined by supply and demand, location, property condition, and comparable sales. Market value changes constantly with market conditions.
Understanding this topic fully means looking at both the big picture and the specific details that apply to your situation. Every property is different, and the strategies that save the most money are the ones tailored to your particular home, location, and circumstances.
Start by gathering the basic facts about your property: its assessed value, the tax rate in your jurisdiction, and any exemptions currently applied. Then compare your situation to what is available. You may find opportunities for savings that you did not know existed.
What Is Assessed Value?
Assessed value is the dollar figure your county assessor assigns to your property for tax purposes. In some states, it equals the full estimated market value. In others, it is a fraction:
| State | Assessment Ratio | $300K Home Assessed At |
|---|---|---|
| California, Florida, NY (outside NYC) | 100% | $300,000 |
| Ohio | 35% | $105,000 |
| Georgia | 40% | $120,000 |
| South Carolina (owner-occupied) | 4% | $12,000 |
| Louisiana | 10% | $30,000 |
| Colorado | ~6.7% | ~$20,100 |
Understanding this topic fully means looking at both the big picture and the specific details that apply to your situation. Every property is different, and the strategies that save the most money are the ones tailored to your particular home, location, and circumstances.
Start by gathering the basic facts about your property: its assessed value, the tax rate in your jurisdiction, and any exemptions currently applied. Then compare your situation to what is available. You may find opportunities for savings that you did not know existed.
Why They Differ
- Assessment ratios: Many states intentionally set assessed value below market value using a fixed ratio
- Assessment caps: States like California (2% annual cap) and Florida (3% cap) limit how fast assessed values can grow, so they fall behind in rising markets
- Assessment lag: Counties reassess on schedules of 2-10 years. Between reassessments, values can drift away from actual market conditions
- Different methods: The assessor may use different comparable sales, different adjustments, or outdated data
- Mass appraisal limitations: Assessors value thousands of properties at once, which introduces more error than an individual appraisal
Understanding this topic fully means looking at both the big picture and the specific details that apply to your situation. Every property is different, and the strategies that save the most money are the ones tailored to your particular home, location, and circumstances.
Start by gathering the basic facts about your property: its assessed value, the tax rate in your jurisdiction, and any exemptions currently applied. Then compare your situation to what is available. You may find opportunities for savings that you did not know existed.
When to Worry
The gap between assessed value and market value only matters in one direction: when your assessed value is higher than it should be. If your assessed value is below market, you are getting a favorable deal. If it is above market, you are overpaying.
Compare your assessed value (adjusted for your state's assessment ratio) to what comparable homes are selling for. If comparable homes sell for $280,000 and your assessment implies a market value of $320,000, you have a case for an appeal.
Our free property tax analyzer does this comparison automatically, adjusting for your state's assessment ratio and comparing to real sales data.
Deadlines in property tax are not flexible. Miss the filing window by even one day and you lose your right to appeal for the entire year. That is another 12 months of overpaying with no recourse. As soon as you receive your assessment notice, find the deadline and mark it on your calendar with a reminder set for two weeks before.
If your deadline has already passed, check whether your state has a secondary appeal window. Some states allow filing with a higher court or board after the initial deadline. If no secondary option exists, start preparing now for next year's appeal so you are ready the moment your next notice arrives.
Your Next Steps
Do not let this information sit. Take action this week:
- Review your most recent assessment notice. Pull it out and check every line. Look for errors in square footage, lot size, bedroom count, and property features. Mistakes here are more common than most homeowners realize.
- Pull comparable sales data. Find 3 to 5 similar properties near you that sold recently. If they sold for less than your assessed value, you have the foundation of a strong appeal.
- Check your exemption status. Contact your county assessor's office and confirm which exemptions are currently applied to your property. Many homeowners qualify for exemptions they have never filed for.
- Set a deadline reminder. Find your appeal deadline and put it on your calendar with a 2-week advance warning. Missing the deadline costs you a full year of potential savings.
Why Most Homeowners Overpay
Studies consistently show that a large percentage of residential properties are over-assessed. The Lincoln Institute of Land Policy found that roughly 40% of assessments are off by more than 10%. That is not a rounding error. On a $350,000 home, a 10% overvaluation means you are paying taxes on $35,000 of value that does not exist.
The reason is simple: assessors use mass appraisal models to value thousands of properties at once. They cannot inspect every home individually. The models rely on averages, which means homes that are below average in condition, location, or desirability often get assessed too high. If your home has any characteristics that reduce its value compared to the average home in your area, your assessment may be inflated.
The only way to fix this is to check your assessment yourself. Compare it to actual sales of similar properties. If the numbers do not match, file an appeal. The process exists for exactly this purpose, and homeowners who use it save an average of $1,000 to $3,000 per year.
Appealing does not increase your assessment. In most jurisdictions, the review board can only lower your value or leave it unchanged. There is no downside to filing a well-prepared appeal.
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Frequently Asked Questions
How do they compare in terms of tax assessed value vs market value: why they are different numbers?
Your tax assessed value and your home's market value are almost never the same number. Market value is what a buyer would pay on the open market. Assessed value is the number the county uses to calculate your tax bill.
What Is Market Value??
Market value is the price a willing buyer would pay and a willing seller would accept in an arm's-length transaction. It is determined by supply and demand, location, property condition, and comparable sales. Market value changes constantly with market conditions.
What Is Assessed Value??
Assessed value is the dollar figure your county assessor assigns to your property for tax purposes. In some states, it equals the full estimated market value, while in others, it is a fraction of the market value.
When to Worry?
The gap between assessed value and market value only matters when your assessed value is higher than it should be. If your assessed value is below market, you are getting a favorable deal. However, if it is above market, you are overpaying. Compare your assessed value (adjusted for your state's assessment ratio) to what comparable homes are selling for.