Property Tax Calculator
Annual property tax from market value, assessment ratio, and mill rate.
What it does
Property tax bills multiply three numbers: what the home is worth, what share of that worth is taxed, and the local rate. Assessment offices set the first two while county, city, school, and special district levies stack into the third, quoted in mills.
The tool above takes market value, assessment ratio percent, and total mills. It returns the assessed value, the yearly tax, and the monthly escrow slice. The default $350,000 home at 100% and 68 mills pays $23,800.00 a year, $1,983.33 a month.
Mill math is plain once the unit lands: 1 mill is $1 per $1,000 of assessed value, so divide mills by 1000 for the decimal rate. Colorado assessor tables work the same stacked example this page checks against: $100,000 at 25% is $25,000 assessed, times 95.965 mills is $2,399.13.
Rates and ratios vary by state and class, and caps can mute the math. Split roll states tax homes and commercial buildings at different ratios, and assessment, rate, or levy limits can hold bills below the raw product. Confirm the class ratio and the stacked mills with the county assessor before budgeting.
How to use
- Type the market value or assessor actual value.
- Type the assessment ratio percent for your class.
- Add every levy into total mills: county plus city plus school plus districts.
- Read yearly tax first, assessed and monthly beside it.
- Compare the effective percent against neighboring bills.
- Confirm class and mills with the county before closing.
Formula
- ratio
- Taxed share of market value in percent.
- mills
- Dollars per $1,000 assessed; decimal rate is mills / 1000.
- stack
- Sum of all overlapping local levies.
Percent form is mills divided by 10: 68 mills is 6.8%. Per $1,000 form is direct: $25,000 assessed at 95.965 mills is 25 x $95.965.
Worked example
Example: $350,000 at 100% and 68 mills
Defaults: market $350,000, ratio 100%, mills 68.
- Assessed: 350,000 x 100 / 100 = $350,000.00.
- Decimal rate: 68 / 1000 = 0.068.
- Yearly tax: 350,000 x 0.068 = $23,800.00.
- Monthly: 23,800 / 12 = $1,983.33.
- Effective: 23,800 / 350,000 = 6.80% of market.
- Tool shows $23,800.00, $350,000.00, $1,983.33.
Reference table
| Item | Math | Result |
|---|---|---|
| 75 mills | 75 / 1000 | 0.075 ($75 per $1,000) |
| 12.3 mills | 12.3 / 1000 | 0.0123 ($12.30 per $1,000) |
| 95.965 mills | 95.965 / 1000 | 0.095965 (9.5965%) |
| Stacked rate | 21.925 + 11.654 + 59.467 + 2.919 | 95.965 mills |
| $100,000 at 25% | 25,000 x 0.095965 | $2,399.13 tax |
| $19,000 at 47.364 mills | 19,000 x 0.047364 | $899.92 tax |
Limits
- Uses one flat ratio and rate; exemptions and caps ignored.
- Classes differ; commercial and residential ratios split in many states.
- Mills move yearly with levies and votes.
- Fees, bonds, and special charges outside mills are excluded.
Common mistakes
- Multiplying market value by mills without the ratio.
- Reading mills as percent: 68 mills is 6.8%, not 68%.
- Counting only the county levy and missing school mills.
- Using last year mills for this year budget.
- Comparing bills across classes without split roll math.
Try it yourself
Quick checks. Answers sit tucked under each question.
$100,000 at 25% and 95.965 mills?
$25,000 assessed, $2,399.13 tax.
$19,000 at 100% and 47.364 mills?
$899.92 tax.
Effective rate on the default?
$23,800 on $350,000 is 6.80%.
Questions
How is property tax figured?
Market times ratio is assessed; assessed times mills over 1000 is the tax.
What is a mill?
$1 per $1,000 of assessed value. Divide mills by 1000 for the decimal rate.
What is the assessment ratio?
The taxed share of market value, such as 100% homes or 25% commercial in the example state.
Why do neighbors pay differently?
Different values, classes, exemptions, and stacked levies move each bill.
Monthly escrow math?
Yearly tax divided by 12. The default holds $1,983.33 a month.
Where do I confirm my numbers?
The county assessor for class ratio and value, the treasurer for stacked mills.
Sources
- Colorado Assessors Reference Library: Assessment Math
- Tax Foundation: A Short Guide to Property Taxes