How the VA combined disability rating works
The Department of Veterans Affairs does not simply add your individual ratings together. If it did, three 30% ratings would equal 90% — but under the VA's combined-ratings table, three 30% ratings actually produce a combined rating of 60%. The difference matters: at 2025 rates, the gap between 60% and 90% (with a spouse and child) is more than $1,800 per month.
The methodology, codified at 38 CFR § 4.25, treats each additional disability as a reduction of the remaining healthy portion of the veteran. The logic is that a person can never be more than 100% disabled, so each successive rating is applied to whatever "whole person" slice is left.
The four-step calculation
- Sort ratings high to low. Order every service-connected disability from highest to lowest percentage.
- Combine bilateral conditions first. If any conditions affect paired extremities (both arms, both legs, or opposing skeletal muscle groups), combine them first using the formula below, then add a 10% bilateral factor to that subtotal.
- Apply the combined-ratings table. Working from the highest remaining rating, combine each successive rating using:
combined = previous + current × (100% − previous) ÷ 100. Repeat until every rating has been folded in. - Round to the nearest 10%. The final figure is rounded to the nearest multiple of 10 (so 84% rounds to 80%, but 85% rounds to 90%).
A veteran has PTSD at 70%, lumbar spine at 20%, tinnitus at 10%, and right knee at 10%.
Step 1 — Sorted: 70, 20, 10, 10.
Step 2 — No bilateral conditions, so skip the bilateral factor.
Step 3 — Combine 70 + 20×(100−70)÷100 = 70 + 6 = 76. Then 76 + 10×(100−76)÷100 = 76 + 2.4 = 78.4. Then 78.4 + 10×(100−78.4)÷100 = 78.4 + 2.16 = 80.56.
Step 4 — 80.56 rounds to 80%.
The bilateral factor (38 CFR § 4.26)
When a veteran has disabilities of both arms, both legs, or paired skeletal muscles, the VA recognizes that the combined effect is greater than the sum of the parts. The bilateral factor adds 10% to the combined value of the bilateral disabilities before they are folded into the rest of the rating.
For example, if a veteran has 10% disability in the right knee and 10% in the left knee, those combine to 19%, and the bilateral factor adds 1.9% (10% of 19%), for a bilateral subtotal of 20.9%. That figure is then combined with any non-bilateral ratings using the standard table.
What this calculator does not do
This tool does not predict whether the VA will grant a particular rating for a particular condition — that depends on the diagnostic code, the C&P examination, and the veteran's symptomatology. It also does not apply Special Monthly Compensation (SMC), which layers additional payments on top of the standard rate for veterans with anatomical loss or loss of use.
For a deeper walk-through of the entire claims process, see our complete guide to VA disability ratings.