Property tax, one unit at a time
A Texas property tax bill is a stack of taxing units. The appraisal district sets the appraised value. Each city, county, school district, and special district adopts its own rate and its own exemptions. This calculator does not multiply one combined rate by one exemption.
For each unit the line is (appraised value minus that unit’s exemptions) times that unit’s rate per $100. Amounts are rounded to the nearest cent on the line, then added. The default tax year is 2025. If you select 2026 and that unit has no adopted 2026 rate in the file, the line uses the 2025 rate and says so.
The state residence homestead exemption removes $140,000.00 from the value taxed by a school district. That amount is Tax Code §11.13(b). An age-65 or disabled homestead adds $60,000.00 on the school line. Those two state amounts do not stack with each other. A local-option percentage homestead, when the dataset has one, is a percent of the full appraised value and at least $5,000.00 under Tax Code §11.13(n). It stacks with the state school amount. It is not a substitute for it.
Sources: Texas Comptroller exemptions, checked 2026-10-07. Rates outside Harris, Fort Bend, Montgomery, Brazoria, and Galveston come from the Comptroller Tax Rates and Levies file for tax year 2025, posted January 2026. Those five counties prefer the county tax office rate where one was collected.
Worked example: $400,000 Houston homestead
Place: City of Houston, Houston ISD. Tax year 2025. General homestead, under 65, no disabled-veteran exemption. Houston City College is left off, because it is optional and not every City of Houston account includes it. No MUD is included. Most MUDs are not in the dataset.
Houston ISD’s 2025 rate in this file is 0.8783 per $100. The school exemption is the state $140,000 plus 20% of $400,000, which is $80,000, for $220,000 exempt and $180,000 taxable. The same home at the 2026 Houston ISD rate of 0.8421 per $100 is a separate line below. The board adopted that rate on October 8, 2026.
| Unit | Rate year | Rate | Exemption | Tax |
|---|---|---|---|---|
| Harris County | 2025 | 0.38096 | $80,000.00 | $1,219.07 |
| Harris County Flood Control District | 2025 | 0.04966 | $80,000.00 | $158.91 |
| Harris County Hospital District (Harris Health) | 2025 | 0.18761 | $80,000.00 | $600.35 |
| Port of Houston Authority | 2025 | 0.0059 | $80,000.00 | $18.88 |
| Harris County Dept. of Education | 2025 | 0.0048 | $80,000.00 | $15.36 |
| Houston ISD | 2025 | 0.8783 | $220,000.00 | $1,580.94 |
| City of Houston | 2025 | 0.51919 | $80,000.00 | $1,661.41 |
The same stack for tax year 2026 totals $5,341.26. Units that still have no adopted 2026 rate keep the 2025 rate and are marked as a fallback: Harris County Dept. of Education, City of Houston. Houston ISD itself is not a fallback. Its 2026 source is the HISD tax page, checked 2026-10-21. Open the property tax calculator and set the year to 2026 if you want that stack. The on-screen total will match this method only when the same units are checked.
- Harris County: Harris County Tax Office, Truth in Taxation Summary (Tax Code 26.16), checked 2026-10-07. https://www.hctax.net/Property/JurisdictionTaxRates
- Harris County Flood Control District: Harris County Tax Office, Truth in Taxation Summary (Tax Code 26.16), checked 2026-10-07. https://www.hctax.net/Property/JurisdictionTaxRates
- Harris County Hospital District (Harris Health): Harris County Tax Office, Truth in Taxation Summary (Tax Code 26.16), checked 2026-10-07. https://www.hctax.net/Property/JurisdictionTaxRates
- Port of Houston Authority: Harris County Tax Office, Truth in Taxation Summary (Tax Code 26.16), checked 2026-10-07. https://www.hctax.net/Property/JurisdictionTaxRates
- Harris County Dept. of Education: Harris County Tax Office, Truth in Taxation Summary (Tax Code 26.16), checked 2026-10-07. https://www.hctax.net/Property/JurisdictionTaxRates
- Houston ISD: Harris County Tax Office, Truth in Taxation Summary (Tax Code 26.16), checked 2026-10-07. https://www.hctax.net/Property/JurisdictionTaxRates
- City of Houston: Harris County Tax Office, Truth in Taxation Summary (Tax Code 26.16), checked 2026-10-07. https://www.hctax.net/Property/JurisdictionTaxRates
What the tax estimate leaves out
Harris County local over-65 dollar exemptions are not applied. A tax year 2025 court order used $320,000 and the HCAD jurisdiction page showed $336,000. Those figures were not reconciled, so the calculator applies neither.
A reported rate of 0 is stored as unavailable. It is not treated as a zero tax. Local homestead percentages outside the five Houston-area counties are not in the file. State school exemptions still apply there, and you can type a local amount the calculator does not have.
The site does not publish a statewide effective rate, a city median price, or a metro appreciation series. Those series are not in the source files. The data sources page lists the files and the gaps.
Mortgage payoff
The mortgage calculator amortizes the remaining balance you enter over the years and months still left. It does not restart a 30-year term unless you enter 30 years and 0 months. Interest for a month is the periodic rate times the balance. The payment is the standard fully amortizing payment. Extra principal is applied before the next month’s interest.
The field starts at 7.4% , the Freddie Mac 30-year fixed for the week of 2026-10-15. The 15-year fixed in that survey is 6.71%. Both were checked 2026-10-21. PMMS history CSV. Change the rate to match your note. The survey is a national weekly average, not a Houston lender’s quote.
The biweekly switch is an approximation of one extra monthly payment a year (26 half-payments). It is not a biweekly draft a servicer might bill with a fee. Articles that walk through a sample loan label that loan as an illustration of this amortization. They are not a forecast of Houston prices.
Home equity
Usable room for a home-equity loan, HELOC, or cash-out refinance is 80% of the value you enter, minus the balance you enter. If that result is below zero, the calculator shows zero. Total equity is value minus balance, and it can be larger than the amount the constitution lets you borrow for those products.
The cap is Texas Constitution Art. XVI §50(a)(6), from Texas Legislature, SJR 60 (85th Legislature). Applies to home-equity loans, HELOCs, and cash-out refinances. A purchase-money mortgage can exceed 80% loan-to-value. Checked 2026-10-07. SJR 60 bill text. An illustration on the calculator page ($500,000 value, $320,000 balance, $80,000 left under the cap) is that arithmetic. It is not an appraisal.
The calculator does not subtract closing costs, does not check credit, and does not decide whether a lender will make the loan. Use the home equity calculator with your own value and balance.
Insurance
There is no insurance calculator. Pages that discuss coverage cite the Texas Department of Insurance or TWIA and do not invent a premium, a deductible percentage, or a share of claims. See the insurance topic.
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