Methodology & Data Sources

This page describes exactly what the calculator does, where every number comes from, and what it deliberately does not model. Every rate used here is published by VA; none of it is estimated or interpolated.

Where the rates come from

Rates are transcribed from VA's own compensation rate tables, one file per rate year. The current year comes from VA's veteran compensation rates page; earlier years come from VA's archived pages for those years.

• 2026 (effective 2025-12-01, 2.8% COLA) — VA source page, transcribed 2026-09-22
• 2025 (effective 2024-12-01, 2.5% COLA) — VA source page, transcribed 2026-09-22
• 2024 (effective 2023-12-01, 3.2% COLA) — VA source page, transcribed 2026-09-22
• 2023 (effective 2022-12-01, 8.7% COLA) — VA source page, transcribed 2026-09-22
• 2022 (effective 2021-12-01, 5.9% COLA) — VA source page, transcribed 2026-09-22
• 2021 (effective 2020-12-01, 1.3% COLA) — VA source page, transcribed 2026-09-22
• 2020 (effective 2019-12-01, 1.6% COLA) — VA source page, transcribed 2026-09-22

Two checks run automatically against this data on every build. The first validates each file against a schema, so a missing or malformed column fails the build rather than reaching the calculator. The second recomputes the year-over-year change of every rating and compares it with that year's cost-of-living adjustment, which is published by the Social Security Administration. A single mistyped digit in any rate breaks that check.

How the calculation works

The calculator walks the retroactive period one month at a time, looks up the monthly rate that applied in that month, and adds it to the total. It then groups consecutive months that share a rate year so the result can be read and checked as a small number of segments rather than a long list of months.

Which months are paid

Counting starts the month after the effective date. 38 U.S.C. § 5111(a)(1) provides that payment may not be made for any period before the first day of the calendar month following the month in which the award became effective. The month of the effective date is therefore not included. The period ends with the month before the award date, at which point regular monthly payments are treated as beginning.

Which rate year applies

VA adjusts its rates on December 1, not January 1. A rate table labelled with a given year takes effect on December 1 of the previous year, so December 2025 is already paid at 2026 rates. The calculator applies that rule month by month and starts a new segment at each December 1 boundary.

How dependents are applied

Dependent amounts apply only from a combined rating of 30%. Below that, the rate is the veteran-alone rate regardless of dependents, and the calculator says so in its results.

At 30% and above, VA's basic table is indexed by a combination of a spouse, one child under 18, and zero, one, or two dependent parents — twelve columns in total. This calculator reads that column directly rather than approximating it. Everything outside those twelve columns is an added amount: each additional child under 18, each child aged 18 to 23 in a qualifying school program, and Aid and Attendance for a spouse. Amounts for a child in a school program are listed separately by VA and are never folded into the one-child column; see 38 U.S.C. § 1115.

What this tool does not model

• A rating that changed during the retroactive period; one rating is assumed throughout.
• A dependent added or removed during the period; one dependent status is assumed throughout.
• Special Monthly Compensation.
• Offsets for concurrent benefits, including CRSC and CRDP.
• The bilateral factor, which affects the combined rating rather than the rate lookup.
• VA's internal processing rules for the final month of a retroactive period, and the exception in 38 U.S.C. § 5111(a)(2) for a catastrophic disability.

Rates before 2020 are not covered by this data set, so periods beginning earlier than December 2019 are declined rather than estimated.

How this data is kept current

VA publishes new rates each December 1, following the cost-of-living adjustment announced in October. When they appear, a new rate file is added and the previous year is re-checked against VA's archived page for it. Until a new year's table is published, months falling in that year are estimated using the most recent published rates, and the result is labelled as such rather than presented as final.

Return to the back pay calculator or read the step-by-step guide.