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Property Tax Reassessment Calculator

Estimate annual and monthly property tax change after reassessment from reassessed value and tax rate.

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Inputs

$/yr
$

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Results

Estimated Annual Tax Change
Estimated New Annual Tax$9,375.00
Estimated Monthly Change$214.58
Effective Tax Rate1.25%

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Assumptions

  • All values, dates, rates, and tax assumptions are entered by the user.
  • Calculations run locally in your browser and are not stored by Calwarden.
  • Results are planning estimates only and are not tax, legal, accounting, lending, or investment advice.

Sensitivity preview

Current Annual Tax -10%: Estimated Annual Tax Change $3,255.00

Current Annual Tax Current: Estimated Annual Tax Change $2,575.00

Current Annual Tax +10%: Estimated Annual Tax Change $1,895.00

Formula: New annual tax = reassessed value x tax rate. For mills, tax rate = mills / 1,000. Annual change = new annual tax - current annual tax. Monthly change = annual change / 12.

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About this Property Tax Reassessment Calculator

Reassessment can change the taxable value used for property tax. This calculator estimates the new annual tax and compares it with your current annual property tax.

Who this calculator is for

  • Investors underwriting a purchase after reassessment.
  • Owners estimating tax changes after renovation, sale, or appeal.
  • Buyers comparing current owner tax bills with likely future tax bills.

When to use it

  • Estimate reassessment impact before buying a property.
  • Budget monthly escrow changes after a new assessed value.
  • Compare percent tax rates and mill-rate assumptions.

How to use this calculator

  1. Enter your current annual property tax.
  2. Enter the reassessed property value.
  3. Choose percent rate or mills, then enter the local tax rate assumption.

Key assumptions

  • All values, dates, rates, and tax assumptions are entered by the user.
  • Calculations run locally in your browser and are not stored by Calwarden.
  • Results are planning estimates only and are not tax, legal, accounting, lending, or investment advice.

Accuracy and testing

Review formula sources, default test cases, assumptions, unit handling, rounding rules, and changelog for this calculator.

View accuracy page

How this calculator works

If rate type is percent, new annual tax = reassessed value x tax rate percent / 100. If rate type is mills, new annual tax = reassessed value x mills / 1,000. Annual change = new annual tax - current annual tax. Monthly change = annual change / 12.
New annual tax = reassessed value x tax rate. For mills, tax rate = mills / 1,000. Annual change = new annual tax - current annual tax. Monthly change = annual change / 12.

Inputs explained

Current annual tax

The property tax currently paid per year, used as the comparison baseline.

Reassessed value

The new assessed or taxable value you want to test.

Tax rate

Enter a percent rate or mill rate based on your local tax authority or estimate.

Understanding your results

The primary output is the estimated annual tax change. Positive values mean a higher tax bill; negative values mean a lower estimated bill. Confirm actual rules with your assessor, attorney, or tax advisor.

Example scenarios

Purchase reassessment

If a property is reassessed at $750,000 and the tax rate is 1.25%, estimated new tax is $9,375. Compared with a current $6,800 bill, the annual increase is $2,575.

Key Features

  • Percent-rate or mill-rate input
  • Annual tax change estimate
  • Monthly escrow impact estimate

Things to Keep in Mind

This calculator does not handle local exemptions, caps, assessment ratios, appeal outcomes, supplemental bills, special assessments, homestead rules, or state-specific reassessment laws. It is not tax or legal advice.

Tips & Best Practices

  • Use taxable value rather than market value when your jurisdiction distinguishes them.
  • Check whether exemptions, caps, or phase-ins apply after sale or reassessment.
  • Run a higher-rate scenario for special districts or pending tax increases.

Glossary of Terms

Reassessed value
A new value assigned for tax purposes, often after sale, renovation, periodic review, or appeal.
Mill rate
Tax dollars per $1,000 of taxable value. A 20 mill rate equals about 2% before other adjustments.
Taxable value
The value to which the tax rate applies after local exemptions, caps, or adjustments.

Frequently Asked Questions

Is reassessed value the same as market value?
Not always. Some jurisdictions use assessment ratios, taxable values, caps, or exemptions. Use the value your local tax rules apply the rate to.
What is a mill rate?
A mill rate is tax per $1,000 of taxable value. For example, 12 mills equals $12 per $1,000 of value, or 1.2% before other adjustments.
Can I rely on this for a purchase budget?
Use it as a planning estimate only. Confirm reassessment rules, exemptions, and future bills with local tax professionals or the assessor.