Property Tax Calculator
Test whether your assessment is worth appealing — an inflated base does not cost you once, it compounds under the annual cap for as long as you own the house.
Property Tax Calculator
Results recalculate instantly on every keystroke. Nothing you type is transmitted.
What this result does not account for
- Appeal odds are your own estimate — no engine can price local board behaviour.
- Models jurisdictions with a percentage cap on annual increases; areas that revalue to full market value each cycle reverse a win at the next revaluation.
- Assumes the assessment ratio stays constant across your holding period.
In short: A $520,000 home assessed at $585,000 is over-valued by 12.50%, costing $877.50 in the first year at a 1.35% rate. Because the excess grows with the base, ten years of it is $9,830.97 — a 19.7× return on a $500 appeal, or $5,890.13 even at 65% odds of winning.
Formula
A is assessed value, M is fair market value, r the total tax rate, g the annual assessment growth cap and n your holding period in years. Exemptions are subtracted from both A and M before the rate is applied.
Worked Example
- Establish fair market value. Three to five recent sales of genuinely comparable properties, adjusted for size and condition. This is the evidence an appeal board actually weighs.
- Measure the gap. $585,000 assessed against $520,000 market is $65,000 of excess base, or 12.50% too high.
- Convert the gap to annual tax. $65,000 × 1.35% = $877.50 in the first year alone.
- Grow it across your holding period. The excess is a percentage of the base, so it rises with the base. Ten years at 2.5% growth totals $9,830.97 — $1,055.97 more than ten times the first year.
- Weigh it against the appeal. $9,830.97 against a $500 filing cost is 19.7×. Even at 65% odds the expected value is $5,890.13.
A homeowner receives a notice assessing a $520,000 property at $585,000. The instinct is to compare $877.50 against the hassle of appealing and let it go. That is the wrong comparison: the inflated base is the starting point for every future increase, so the real stake is $9,830.97.
Strengths & Limits Of This Model
Where this engine is strong
- Prices the full holding period, not just the first year — the figure that actually decides an appeal.
- Separates the compounding effect from simple arithmetic so you can see what year-one maths misses.
- Expected-value framing weighs the cost of appealing against realistic odds.
Where it stops
- Cannot value the evidence you hold — comparable sales decide appeals, not arithmetic.
- Ignores any special assessment, levy or bond that sits outside the standard rate.
- An appeal can trigger a review that raises an under-assessment.
Practical Use Cases
Deciding whether to appeal an assessment
The first-year figure understates the stake by an order of magnitude. Price the full holding period before deciding it is not worth the paperwork.
Budgeting the true cost of a home
Property tax is the one housing cost that never amortises away. Fold the annual figure into your affordability work with the Mortgage Affordability Calculator.
Comparing two towns before buying
A lower price in a higher-rate jurisdiction can cost more over a decade. Run both and compare the cumulative figure, not the headline rate.
Checking an escrow shortage
If your lender collects taxes monthly, an assessment jump lands as an escrow shortfall — reconcile it with the Escrow Calculator.
Methodology & Editorial Standards
The engine subtracts any exemption from both the assessed and market bases before applying the rate, so relief that follows the property does not distort the comparison. Cumulative figures compound the base at the annual growth rate over the holding period, with the first year at exponent zero — the assessment you are appealing is the one already on your notice. This models jurisdictions with a percentage cap on annual assessment increases; areas that reassess to full market value each cycle behave differently, since a successful appeal there is reversed at the next revaluation. Rates are entered as a single combined percentage; if your jurisdiction quotes mills, divide by ten to convert. Appeal odds are your own estimate and no engine can improve on local knowledge. The engine implements the standard published formula for this calculation. Inputs are validated for domain and sign before evaluation, and any undefined case returns an em-dash rather than a spurious value.
Computation runs in IEEE-754 double precision at full internal precision; rounding to two decimal places occurs strictly at the display layer, so no cumulative drift enters the result. All monetary outputs use accounting presentation — grouped thousands, two decimals, negatives in parentheses — so figures can be transcribed directly into a model or working paper. Division-by-zero and out-of-domain inputs return an em-dash rather than a misleading number.
This engine was reconciled against an independent reference implementation and hand-verified for the worked example above before release. Our full five-stage review process is published on the About Us page.
Disclaimer. This calculator is provided for informational and modelling purposes only and does not constitute financial, tax, legal, medical, or engineering advice. Verify all figures with a qualified professional before acting on them.
Property Tax Calculator — 20 Expert FAQs
20 analyst-written answers to the questions practitioners actually ask — optimised for voice and answer-engine retrieval.
Is it worth appealing my property tax assessment?
If you are over-assessed by more than a few percent, almost always. A $65,000 over-assessment costs $877.50 in year one but $9,830.97 across ten years, against a filing cost of a few hundred dollars.
How much can I save by appealing property taxes?
The saving equals the reduction in assessed value multiplied by your tax rate, every year you own the property. Here a $65,000 reduction saves $877.50 annually and $9,830.97 over a decade.
Why is my property tax bill higher than my neighbour's?
Assessment dates, exemptions and appeal history all differ. Two identical houses can carry very different assessed values simply because one owner appealed and the other did not.
What is the difference between assessed value and market value?
Market value is what the property would sell for. Assessed value is the figure your jurisdiction taxes, which may be a fixed ratio of market value or a stale number from an older revaluation.
Does a successful appeal lower my taxes permanently?
It lowers the base from which future increases are calculated, which is why the saving compounds. In jurisdictions that revalue to full market value each cycle the benefit lasts only until the next one.
Can appealing my assessment backfire?
It can. An appeal invites a fresh review, and if you are actually under-assessed the board may raise the figure. Only appeal when you have comparable sales showing you are over-valued.
What evidence do I need for a property tax appeal?
Three to five recent sales of genuinely comparable properties, plus photographs of any condition issues the assessor could not see. Opinion carries no weight; recorded sale prices do.
How does a homestead exemption affect this?
It reduces the taxable base before the rate applies, so it lowers both the correct and the inflated bill. It never cures an over-assessment; the excess remains.
What is an effective property tax rate?
Tax paid divided by true market value. Here the 1.35% nominal rate becomes 1.520% effective, because the tax is levied on a value $65,000 higher than the house is worth.
How do mills convert to a percentage?
One mill is one dollar per thousand of value, so 13.5 mills is 1.35%. Divide the millage rate by ten to get the percentage this calculator expects.
Why does the overpayment compound?
Because the excess is a fixed percentage of the base, and the base grows each year under the cap. Multiplying year one by ten understates the true cost by $1,055.97 here.
Do property taxes go down when home prices fall?
Not automatically. Assessments often lag the market badly on the way down, which is exactly when appeals succeed most often.
Is property tax deductible?
State and local taxes including property tax are deductible if you itemise, subject to the combined SALT cap. Most filers now take the standard deduction and get no benefit.
How often can I appeal?
Most jurisdictions allow one appeal per assessment cycle within a short window after notices are issued, often 30 to 45 days. Missing the window costs you the whole year.
Should I hire someone to appeal for me?
Contingency firms typically take a third to a half of the first year's saving. Given the saving compounds for as long as you own the property, that can still be worthwhile if you will not file yourself.
Is this property tax calculator free to use?
Yes. It is free, requires no account, and has no usage limits. ApexConverter is funded by contextual advertising, never by selling user data.
Is my data sent to a server?
No. The engine runs as Vanilla JavaScript inside your browser under our Zero-Server Client-Side Execution model. Your figures are computed locally and are never transmitted, logged, or stored.
How accurate is this calculator?
It applies the standard closed-form formula in IEEE-754 double precision, rounding only at the display layer. The engine is reconciled against an independent reference implementation before release.
Does it work on mobile?
Yes. The interface is mobile-first with numeric keypad hints and is tested down to a 320-pixel viewport with no horizontal scrolling.
Can I use it offline?
Largely, yes. Because computation is client-side, the page continues to calculate without a network connection once it has loaded.