Finance & Economics · Real Estate & Mortgages
Property Tax Calculator
Calculates annual property tax owed based on assessed property value, assessment ratio, and mill rate (or tax rate percentage).
Calculator
Formula
T is the annual property tax owed (in dollars). V is the market or appraised value of the property. A is the assessment ratio — the fraction of market value used as the taxable assessed value (e.g. 0.80 for 80%). m is the mill rate, expressed in mills (1 mill = $1 of tax per $1,000 of assessed value). Multiplying V by A yields the assessed value; multiplying by m/1000 converts mills to a dollar tax amount.
Source: International Association of Assessing Officers (IAAO), Standard on Property Tax Policy, 2010.
How it works
Property taxes are levied by local governments — counties, municipalities, and school districts — to fund public services such as schools, roads, and emergency services. The tax is calculated not simply on the full market value of a property, but on its assessed value, which is determined by applying an assessment ratio to the market value. This ratio varies by jurisdiction and can range from as low as 10% in some states to 100% (full value assessment) in others.
The core formula is T = (V × A) × (m / 1000), where V is the market value, A is the assessment ratio expressed as a decimal, and m is the mill rate. A mill is one-thousandth of a dollar — so a mill rate of 25 means $25 in tax for every $1,000 of assessed value, or equivalently a 2.5% tax on assessed value. Many jurisdictions also allow exemptions — such as homestead exemptions for primary residences, senior citizen exemptions, or veteran exemptions — which reduce the taxable assessed value before the mill rate is applied. This calculator subtracts those exemptions from the assessed value before computing the final tax bill.
Real estate investors use property tax estimates to determine net operating income (NOI) and capitalization rates. Mortgage lenders require monthly property tax escrow contributions, typically one-twelfth of the annual bill. Buyers comparing homes in different municipalities should always compare the effective tax rate — annual tax divided by market value — to make apples-to-apples comparisons since mill rates and assessment ratios vary independently.
Worked example
Suppose you are purchasing a home with a market value of $350,000 in a county with an assessment ratio of 80% and a mill rate of 25 mills. You qualify for a homestead exemption of $10,000.
Step 1 — Calculate assessed value: $350,000 × 0.80 = $280,000
Step 2 — Subtract exemptions: $280,000 − $10,000 = $270,000 taxable assessed value
Step 3 — Apply mill rate: $270,000 × (25 / 1,000) = $270,000 × 0.025 = $6,750 annual property tax
Step 4 — Monthly escrow estimate: $6,750 ÷ 12 = $562.50 per month
Step 5 — Effective tax rate: $6,750 ÷ $350,000 = 1.929% of market value
This effective rate gives a clean basis for comparing this property's tax burden to another property in a different jurisdiction, regardless of how assessment ratios and mill rates differ between them.
Limitations & notes
This calculator provides an estimate based on the inputs you provide. Actual property tax bills depend on several factors that may not be captured here. First, assessed values are set by local assessors and may differ significantly from market value — assessors do not always update values annually, and some jurisdictions reassess only on sale. Second, mill rates can change each year as local governments adjust budgets; the rate used in this calculator reflects a point-in-time estimate. Third, exemptions vary widely by jurisdiction — homestead, senior, disability, and agricultural exemptions each have specific qualification rules that this calculator cannot verify. Fourth, some jurisdictions levy additional special assessment taxes (e.g. for local improvement districts, sewer bonds) that are not captured in the base mill rate. Fifth, this calculator does not account for tax phase-ins common in some states where newly assessed values are introduced gradually to prevent sudden tax spikes. Always verify your assessed value on your local assessor's website and consult your jurisdiction's tax authority for the most accurate figures.
Frequently asked questions
What is a mill rate and how does it differ from a tax rate percentage?
A mill rate expresses tax as dollars per $1,000 of assessed value. For example, a mill rate of 20 means $20 in tax per $1,000 of assessed value, which is equivalent to a 2.0% tax rate on assessed value. To convert a mill rate to a percentage, simply divide by 10: a mill rate of 25 equals a 2.5% assessed-value tax rate.
Why is my taxable assessed value different from my home's market value?
Most jurisdictions assess property at a fraction of market value called the assessment ratio, which can range from 10% to 100% depending on local law. Additionally, exemptions such as homestead or senior exemptions reduce the taxable assessed value further. The result is that the base on which tax is actually levied is often considerably lower than what you paid for the home or what it would sell for today.
What is a homestead exemption and how much does it save?
A homestead exemption reduces the taxable assessed value of a primary residence, lowering the property tax bill. The dollar amount varies widely: Florida offers up to $50,000, Texas up to $100,000 (as of 2023), and many states offer $5,000–$25,000. At a 25-mill rate, a $25,000 homestead exemption saves $625 per year ($25,000 × 0.025).
How do I find my local mill rate and assessment ratio?
Both figures are published by your local government. The mill rate (sometimes called the tax rate or levy rate) is typically set annually by your county or municipal government and is posted on the tax collector's or assessor's website. The assessment ratio is set by state law or local policy and is also available from the assessor's office or your property tax bill.
How does property tax affect real estate investment returns?
Property taxes are a direct operating expense that reduces net operating income (NOI), which in turn lowers a property's capitalization rate value. For investment properties, effective tax rates above 2–3% of market value can meaningfully compress returns, especially in markets with compressed cap rates of 4–5%. Investors underwriting deals should always verify the actual tax bill rather than estimating from purchase price, since assessed values can lag market values significantly in some jurisdictions.
Last updated: 2025-01-15 · Formula verified against primary sources.