It's Simpler Than It Looks
Property tax calculations sound intimidating (assessed value, mill rates, assessment ratios) but once you break it down step by step, it's actually pretty straightforward math. The formula at the core of it all is:
Annual Property Tax = Taxable Value × Tax Rate
Where:
- Taxable Value = Assessed Value − Exemptions
- Assessed Value = Market Value × Assessment Ratio
- Tax Rate = the combined rate from your school district, county, city, and any special districts
Walk through the steps below and you'll be able to estimate the tax bill on any property in the US, including one you'reu're thinking about buying.
Step 1: Find the Market Value
Market value is what your home would sell for on the open market. You can find estimates from:
- Your county assessor's website (they publish their market value estimate)
- Real estate platforms like Zillow, Redfin, or Realtor.com
- A recent appraisal
- The purchase price (if recently sold)
For our example: let's say market value = $350,000.
Step 2: Calculate the Assessed Value
Most states don't tax the full market value. They apply an assessment ratio: a percentage of market value that becomes the assessed value.
Common assessment ratios:
- California: 100% of purchase price (then capped at 2% annual increases)
- Texas: 100% of market value
- Florida: 100% of market value (called "just value")
- Illinois: 10% of market value (33.33% in Cook County)
- South Carolina: 4% of market value for owner-occupied homes
- Ohio: 35% of market value
For our example, using a state with 100% assessment ratio:
$350,000 × 100% = Assessed Value: $350,000
In a state with a 35% ratio (like Ohio):
$350,000 × 35% = Assessed Value: $122,500
Step 3: Subtract Exemptions to Get Taxable Value
Exemptions reduce the assessed value before the tax rate is applied. The most common is the homestead exemption for primary residences.
For our example, assume a $25,000 homestead exemption:
$350,000 − $25,000 = Taxable Value: $325,000
If you qualify for additional exemptions (senior, veteran, disability), subtract those too. See our guide on homestead exemptions for details on what's available in your state.
Step 4: Apply the Tax Rate
The tax rate (also called mill rate) is set by your local taxing authorities. It's the combined rate from your school district, county, city, and any special districts.
Tax rates are usually expressed in two ways:
- As a percentage: 1.5% means $15 of tax per $1,000 of taxable value
- As mills: 15 mills = 1.5% (one mill = $1 per $1,000)
For our example, using a 1.4% combined rate:
$325,000 × 0.014 = Annual Tax: $4,550
Monthly: $4,550 ÷ 12 = $379 per month
Worked Examples by State
Texas Example
- Home value: $400,000
- Assessment ratio: 100% → Assessed: $400,000
- Homestead exemption (school taxes): $100,000 → Taxable for school: $300,000
- School rate: 0.89% → School tax: $2,670
- County + city + other: ~0.65% on full $400,000 → $2,600
- Total annual tax: ~$5,270
Florida Example
- Home value: $350,000
- Just value: $350,000 (assessed at 100%)
- Homestead exemption: $50,000 → Taxable value: $300,000
- Combined mill rate: 18 mills (1.8%)
- Annual tax: $300,000 × 0.018 = $5,400
Ohio Example
- Home value: $300,000
- Assessment ratio: 35% → Assessed value: $105,000
- Owner-occupancy reduction: 2.5% credit applied
- Combined mill rate: 60 mills (6%) on assessed value
- $105,000 × 0.06 = $6,300, minus 2.5% credit = ~$6,143 annual tax
- Note: Ohio's high mill rate applies to a reduced assessed value. The effective rate is roughly 2.05% of market value
How to Find Your Actual Tax Rate
The fastest way to find the real tax rate for any location:
- Search for "[your county] property tax rate" or "[your county] mill levy"
- Visit your county assessor or tax collector website (rates are public record)
- Look at an existing property's tax bill in the area (public record in most counties)
- Use our property tax calculator: enter your state, county, and city to see median effective rates
Calculating Your Monthly Budget
If your lender uses an escrow account (required for most mortgages with less than 20% down), your property taxes are collected monthly alongside your mortgage payment. To calculate your monthly escrow contribution:
Monthly Tax Escrow = Annual Tax Bill ÷ 12
Add this to your principal, interest, and homeowner's insurance to get your true monthly housing payment (PITI).
Quick Reference: Property Tax Calculation Steps
- Find market value
- Multiply by assessment ratio → Assessed value
- Subtract exemptions → Taxable value
- Multiply by tax rate → Annual tax
- Divide by 12 → Monthly cost
For a faster estimate, use our property tax calculator. For strategies to reduce what you owe, read our guide on how to lower your property tax bill.