The engine

Two calculations are the whole product.

An equity analysis on the public appraisal roll, and a homestead cap check that says whether winning would change your bill. No MLS, no sales prices, no valuation model: only what the appraisal district itself published, compared the way Texas law says to compare it.

1 · Equity analysis

Find the peers, adjust, take the median.

  1. Select. Improved single-family parcels in the same appraisal neighborhood code, with living area within 15% of the subject, built within about six years, same quality class.
  2. Adjust. Each comp's $/sq ft is moved toward the subject for size, age, land and quality, using stated per-square-foot factors that appear in the packet.
  3. Compare. The median adjusted $/sq ft times the subject's living area is the indicated value. If the subject sits materially above it, that's the value to ask for.

This is the “equal and uniform” standard in Texas Tax Code §41.43(b)(3): the appraised value should not exceed the median appraised value of a reasonable number of comparable properties appropriately adjusted.

Worked example · 2107 Kinney Ave, Austin
Comp$/sq ftAdj.Adjusted
1815 Bluebonnet Ln$301$3$298
2114 Kinney Ave$307$6$301
1720 Bluebonnet Ln$307$4$303
1907 Kinney Ave$308$2$306
2201 Rabb Rd$307+$1$308
2010 Oxford Ave$307+$3$310
2009 Kinney Ave$316$4$312
2306 Rabb Rd$315+$1$316
Median adjusted $/sq ft (4th and 5th ranked)$307
× 1,842 sq ft, rounded to $1,000$566,000
Subject is appraised at$612,400 · $332/sq ft
Over-assessed by$46,400 (7.6%)

2 · Homestead cap check

A market-value win may not lower the bill.

On a homestead, the taxable value can rise at most 10% a year, whatever the market value does. So the bill is set by the capped value, not the market value. A protest lowers the market number; it only reaches the bill once the market value falls below the cap.

Parity runs this before anyone pays. If the reduction wouldn't reach the bill this year, the verdict says so and recommends waiting. If there's no homestead exemption on file, it says to file that first: it's free and usually worth more than the protest.

Uncapped · 2107 Kinney Ave

Market value = capped value$612,400
Reduce to$566,000
Bill this year$974

At the 2025 combined rate of 2.10%.

Capped · same house, different history

Market value$612,400
Capped (taxable) value$541,200
Reduce to$566,000
Bill this year$0

Still above the cap. We'd tell you to wait.

Data and limits

Public roll data, nothing else.

Every number comes from the county appraisal district's certified or preliminary roll, retrieved the night it posts and dated on every page of the packet. Parity has no sales prices, no listings and no valuation model, which is why it's an honest second opinion and not an appraisal.

Precomputed

Every homestead in a supported county is checked the night notices drop, so a verdict is a lookup, not a wait.

Explainable

The comps, the factors and the median are printed. A review board can check the arithmetic, and so can you.

County-shaped

Deadlines, portals and ARB formats live in per-county adapters. New county, new data; same engine.

Run it on my address