Methodology
The exact formulas behind every tool on this site, where the numbers come from, and what the tools deliberately will not do.
Short answer: each taxing unit's tax is max(0, value − exemption) / 100 × unit rate, computed separately for your county, city, school district, and any special districts, then summed. Rates come from the Texas Comptroller's official 2025 dataset; state-level exemption amounts come from the Texas Tax Code and the Propositions passed in November 2025.
Formulas
Tax estimator
For each taxing unit selected: taxable value = max(0, value − exemption), then tax = taxable value / 100 × rate, where rate is dollars per $100 of taxable value, as published by the taxing unit. The total bill is the sum of every selected unit's tax. We never collapse this into one blended "county rate" — see why below.
Protest savings
For each selected unit: savings = (taxable(noticed value) − taxable(target value)) / 100 × rate, summed across units. "Noticed value" is the appraised value on your notice of appraised value; "target value" is the value you believe the evidence supports.
Homestead cap (Tax Code §23.23)
capped appraised value = min(market value, prior-year appraised value × 1.10 + value of new improvements this year), available only if the property qualified as a residence homestead on January 1 of the prior year.
Why there is no single "county rate"
Property tax rates are set independently by each taxing unit — county, city, school district, and special districts such as MUDs, ESDs, hospital districts, and flood-control districts. These can differ by thousands of dollars for two addresses in the same county. Publishing one blended county-level number would misstate what most homeowners actually owe, so no tool on this site produces a single point-estimate rate; you select the specific units that cover your address, or the rate tables show the full range by unit.
Data sources
- Tax rates: Texas Comptroller of Public Accounts, Property Tax Rates in Texas (2025 dataset, version 01/28/2026).
- School district homestead exemption ($140,000) and the 10% appraisal cap: Texas Tax Code §11.13 and §23.23.
- Over-65/disabled additional school exemption ($60,000) and the general homestead increase: constitutional amendments Proposition 11 and Proposition 13, approved by Texas voters in November 2025.
- Protest deadlines: Texas Tax Code §41.44. General protest guidance: Texas Comptroller, Property Tax Protests and Appeals.
- Circuit-breaker appraisal limitation: Texas Tax Code §23.231.
Exemption amounts used (2025)
- School district general homestead exemption: $140,000 (Tax Code §11.13(b), amount set by Proposition 13, November 2025).
- School district additional exemption for homeowners 65+ or disabled: $60,000 on top of the general exemption, for $200,000 total (Tax Code §11.13(c)/(d), amount set by Proposition 11, November 2025).
- County, city, and special-district homestead exemptions are locally optional and unit-specific. No tool on this site assumes any of them; you'd need to check your specific units' exemption pages.
- 10% homestead appraisal cap: Tax Code §23.23, applies once a property has qualified as a homestead for a full prior tax year.
- Circuit-breaker 20% appraisal-increase limitation: Tax Code §23.231, for certain non-homestead real property with an appraised value at or below about $5 million, adjusted annually for inflation. This is shown as informational context only, separate from the homestead cap tool.
Limitations
- Special districts (MUDs, ESDs, hospital districts, flood-control districts, and similar) depend on the exact address, not just the county or city. The special-district list on each tool must be checked against your appraisal district's own records.
- Rates and exemption amounts can change year to year; this site uses the 2025 dataset and the exemption amounts current as of the date in the footer.
- These tools estimate; they do not access your actual appraisal record, do not file anything, and are not a substitute for your appraisal district's own notice, bill, or online account.
- txpropertymath.com does not negotiate with, represent, or communicate with any appraisal district or appraisal review board on a user's behalf, for any user, under any circumstance.
County-page expansion policy
Rate tables are currently published for six counties — Travis, Harris, Dallas, Bexar, Tarrant, and Williamson — each manually checked against the Comptroller dataset and the local appraisal district. This is a deliberate, bounded launch set, not a starting point for automatic expansion. Any additional county page added later will go through the same manual verification before publishing, as standing policy, not an automated or templated rollout.
Maintainer
Maintained by txpropertymath.com, an independent Austin, Texas publisher. This site's content was drafted with AI assistance; every rate, exemption amount, and statutory citation was checked against the official sources listed above before publishing.
Refresh cadence
Rate tables are refreshed when the Texas Comptroller publishes a new annual dataset, typically in January, and exemption amounts are updated promptly after any statewide constitutional election that changes them.