The VA combines multiple service-connected disabilities using a 'whole person' method that is not addition. This calculator implements the official 38 CFR 4.25 combined ratings table, applies the 38 CFR 4.26 bilateral factor, and looks up the 2024 monthly compensation rate so veterans can verify their VA rating decision letter or estimate the impact of a new claim.
Why combined ratings are not just addition
The VA assumes every veteran starts at 100% able-bodied and that each disability can only reduce what is still left. A 50% rating takes half of your remaining efficiency, leaving 50%; a second 30% rating then takes 30% of that remaining 50%, leaving 35%. Combined rating is 100 minus 35, which equals 65%, then rounded up to 70%. That is why two 50% disabilities combine to 75%, not 100%, and why adding a 10% disability to a 90% rating rarely changes the final number.
Inputs and what they mean
Each row represents one service-connected disability from your VA rating decision. The rating is the VA-assigned percentage (0, 10, 20, ..., 100). The category is informational and helps you label the row; it does not change the math. The bilateral checkbox flags paired-limb conditions — both knees, both shoulders, both eyes — so the 10% bilateral factor can be applied when you enable the master toggle. Mark at least two disabilities as bilateral for the factor to fire; a single bilateral checkbox is treated as non-bilateral.
TDIU and the 100% threshold
If your combined rating is below 100% but service-connected disabilities prevent you from maintaining substantially gainful employment, you may qualify for Total Disability based on Individual Unemployability (TDIU). Schedular TDIU under 38 CFR 4.16(a) requires either one disability rated 60% or higher, or a combined rating of 70% with at least one disability at 40%. The calculator flags both pathways. Veterans below those thresholds can still pursue extraschedular TDIU under 4.16(b) through the Director of Compensation Service.
Limits of this estimator
The pay table is the 2024 rate for a veteran with no dependents. Spouse, dependent children, dependent parents, and Aid & Attendance benefits add to that base. Special Monthly Compensation (SMC) for loss-of-use, housebound status, or specific anatomical losses pays at higher rates not modeled here. Cost-of-living adjustments (COLAs) shift the base table every December. Use this calculator to verify the schedular logic on your rating decision letter; cross-check the dollar amount against your VA Letter Generator or eBenefits before relying on it.