Property Tax Appeal Calculator

A property tax appeal challenges the value your assessor put on your home. You are not arguing that the tax rate is too high, which is not appealable, but that the number it is multiplied by is wrong.

Core formulas: Annual Tax = Assessed Value × Rate Saving = (Current Assessed Value − Target Assessed Value) × Rate

The two ways a rate gets quoted, which is where most confusion starts. A mill rate is dollars per $1,000 of assessed value, so 14 mills means $14 per thousand. A percentage rate says the same thing differently: 14 mills is 1.4%. Divide mills by 10 to get the percentage, multiply the percentage by 10 to get mills. The dropdown above takes either, so use whichever your tax bill prints.

The step almost every online guide skips: the assessment ratio. Plenty of states do not assess at full market value. South Carolina assesses an owner-occupied home at 4% of market value. Massachusetts, New Jersey and most of New England use 100%. Arkansas uses 20%, Alabama 10%. If your county assesses at 40% and you march in with comparable sales showing $375,000, the right target assessment is $150,000, not $375,000.

Comparing a raw assessment against raw sale prices in a fractional-assessment state produces a number that looks catastrophic and means nothing. Your assessment notice states the ratio, and so does the assessor’s website.

Worked example: Assessed at $420,000, comparable sales averaging $375,000, a 100% assessment ratio, 14 mills.

• Current tax: $420,000 × 1.4% = $5,880 a year
• If the appeal lands at $375,000: $5,250 a year
• Saving: $630 a year, and a $400 appraisal pays for itself in about eight months

How to build an appeal that wins:

1. Three to five sales of genuinely similar homes, closed within the last six to twelve months, in your own neighbourhood. Two identical houses on opposite sides of a school boundary are not comparable.
2. Photographs of anything wrong with it. A failing roof, a wet basement, a road that got busier.
3. The assessor’s own record card. Wrong square footage, a bedroom that does not exist, a garage counted twice. Factual errors are the easiest wins because nobody has to agree about value.
4. An independent appraisal if the numbers justify it. It runs $300 to $500 and it is the strongest single piece of evidence you can bring.

What to expect: homeowners who show up with comparable sales win a reduction something like half the time, and typical reductions run a few hundred to a couple of thousand dollars a year. The deadline is short and unforgiving, usually 30 to 60 days from the assessment notice, and missing it means waiting a year.

One thing worth knowing before you start. A successful appeal usually holds only until the next revaluation cycle, which in most places is every three to five years. The saving is real but it is not permanent, so weigh a paid appraisal against how long the reduction is likely to last.