Property Tax Increase Calculator: Percentage Change in Your Tax Bill
Work out the percentage increase in your property tax between two years — and the dollar difference on your annual bill — so you can see how much your taxes have risen and whether an appeal is worth pursuing.
Adjust the inputs and select Calculate for a full breakdown.
Compare Common Scenarios
How the numbers shift across typical situations for this calculator:
| Scenario | Tax increase | Dollar change |
|---|---|---|
| $4,200 to $4,620 (+10%) | 10.00% | 420 |
| $3,000 to $3,900 (+30%, reassessed) | 30.00% | 900 |
| $6,500 to $6,695 (+3%) | 3.00% | 195 |
| $5,000 to $4,800 (−4%, won appeal) | -4.00% | -200 |
How This Calculator Works
Enter your previous and current property tax bills. The calculator finds the percentage change between them and the dollar difference. Compare year over year to spot a jump worth investigating.
The Formula
Percentage Change
Old is the starting value, New is the ending value
Worked Example
A bill rising from $4,200 to $4,620 is a 10% increase — $420 more a year. Property taxes rise for two reasons: your home's assessed value went up, or the local tax rate (millage) increased. A large jump usually means a reassessment. If the new assessed value looks higher than what your home would actually sell for, you may have grounds to appeal — and a successful appeal lowers the bill for years, not just once.
Key Insight
A property tax spike is one of the few tax increases you can actually contest. The bill is assessed value times the tax rate, so a jump comes from one or both rising. Reassessments are the usual culprit, and assessors are not infallible — if comparable homes sold for less than your assessed value, or the assessment lists features your home doesn't have, you have a case. Appeals are often free or cheap to file and, because they reset the assessed value, save money every year going forward, not just once. Worth checking before paying: the deadline to appeal is usually short after the assessment notice arrives, and many homeowners overpay simply by missing it. Also confirm you're getting any homestead, senior, or veteran exemptions you qualify for.
Frequently Asked Questions
How is the property tax increase calculated?
Subtract the old bill from the new bill, divide by the old bill, and multiply by 100. From $4,200 to $4,620 is ($4,620 − $4,200) / $4,200 = 10%, a $420 increase.
Why did my property tax go up?
Either your home's assessed value rose, the local tax rate (millage) increased, or both. A large jump usually signals a reassessment of your home's value. Your assessment notice or tax bill should break down the assessed value and the rate so you can see which changed.
Can I appeal a property tax increase?
Often yes, by appealing the assessed value (you generally can't appeal the tax rate). If comparable homes sold for less than your assessed value, or the assessment has factual errors, you may win a reduction. Appeals are usually low-cost and reset the value, saving money for years — but the deadline after the assessment notice is short.
How much can property taxes increase in a year?
It varies by location. Some states cap annual assessed-value increases (for example, limits tied to a percentage or inflation), while others have no cap and bills can jump sharply after a reassessment. Check your local rules — a cap may mean an unusually large increase is itself an error worth questioning.
Are there exemptions that lower my bill?
Frequently. Homestead exemptions (for a primary residence), and senior, veteran, or disability exemptions can reduce the taxable value. Many homeowners qualify but never apply. Check with your local assessor — claiming an exemption you're entitled to can offset or reverse an increase.
Related Calculators
Methodology & Review
The increase is the change between the old and new tax bill divided by the old bill, multiplied by 100. It compares two bill amounts directly and does not separate the effect of an assessed-value change from a millage (tax-rate) change.
Written by Ugo Candido · Last updated May 22, 2026.