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One of the most common sources of frustration for veterans navigating the VA disability system is the combined ratings formula. Many veterans reasonably assume that if they have one condition rated at 50 percent and another rated at 30 percent, their combined rating would be 80 percent. It is not. Under the VA's formula, those two ratings combine to 65 percent. Understanding why this happens and how the math works is essential for any veteran managing multiple service-connected conditions.
The combined ratings formula is defined in 38 CFR 4.25 and is based on the concept of "whole person" disability. The VA starts with the premise that you begin at 100 percent healthy. Each disability rating is applied not to the original 100 percent, but to the remaining non-disabled portion of your body. This is sometimes called the "remaining efficiency" method.
Here is how it works step by step. Say you have two conditions: one rated at 50 percent and one rated at 30 percent. The VA starts with 100 percent efficiency. The first rating of 50 percent is applied: 100 times 0.50 equals 50 percent disability, leaving 50 percent remaining efficiency. The second rating of 30 percent is then applied to the remaining 50 percent, not to the original 100 percent: 50 times 0.30 equals 15 percent additional disability. Your total combined disability is 50 plus 15, which equals 65 percent. The VA then rounds to the nearest 10 percent, giving you a final combined rating of 70 percent.
The order in which conditions are combined does not change the final result. Whether you apply the 50 percent first or the 30 percent first, the mathematical outcome is identical. This is because the formula uses multiplication, and multiplication is commutative. However, the VA convention is to list conditions from highest to lowest rating for clarity.
Rounding plays a significant role in the final rating. The VA rounds to the nearest 10 percent, with the standard rounding rule: 0.5 and above rounds up, below 0.5 rounds down. This means a combined value of 65 percent rounds to 70 percent, while 64 percent would round to 60 percent. That single percentage point can mean a significant difference in monthly compensation. For a single veteran with no dependents in 2026, the difference between a 60 percent and 70 percent rating is over $400 per month.
When you have three or more conditions, the same principle applies iteratively. Start with 100 percent efficiency, apply the highest rating, then apply each subsequent rating to the remaining efficiency. For example, with ratings of 50, 30, and 20 percent: start at 100, apply 50 percent (50 disability, 50 remaining), apply 30 percent to the remaining 50 (15 disability, 35 remaining), apply 20 percent to the remaining 35 (7 disability, 28 remaining). Total disability is 50 plus 15 plus 7 equals 72 percent, which rounds to 70 percent.
The bilateral factor is an additional calculation that applies when a veteran has disabilities affecting both paired extremities, meaning both arms, both legs, both ears, or both eyes. Under 38 CFR 4.26, the VA adds 10 percent of the combined value of the bilateral conditions before incorporating them into the overall combined rating. For example, if you have a 20 percent rating for your left knee and a 10 percent rating for your right knee, those combine to 28 percent. The bilateral factor adds 10 percent of 28, which is 2.8 percent, for a bilateral total of 30.8 percent. This slightly higher value is then combined with your other non-bilateral conditions using the standard formula.
Understanding this math has practical implications for claim strategy. Because each subsequent rating is applied to a smaller remaining efficiency, the mathematical impact of each additional condition decreases. A veteran going from 0 to 50 percent gains 50 percentage points. But going from 50 to adding a 30 percent condition only gains 15 percentage points (combined 65, rounded to 70). This does not mean additional claims are not worth pursuing. The compensation difference between each 10 percent tier is meaningful, and reaching certain thresholds like 70 percent or 100 percent unlocks additional benefits.
At 30 percent and above, veterans with dependents receive additional compensation for their spouse and children. At 70 percent, veterans may become eligible for Total Disability based on Individual Unemployability (TDIU) if they cannot maintain substantially gainful employment due to their service-connected conditions. At 100 percent, veterans receive the maximum schedular compensation and may qualify for Special Monthly Compensation categories that provide additional payments for specific severe disabilities.
The Claim Recon Rating Calculator applies the official 38 CFR 4.25 formula and the bilateral factor from 38 CFR 4.26 automatically. You can enter your current conditions and ratings to see your accurate combined rating, then add hypothetical conditions to model how a potential new rating would affect your overall compensation. This can help you prioritize which conditions to claim and understand the financial impact of each potential rating.
Disclaimer: This article is for educational and informational purposes only. It does not constitute legal, medical, or VA claims advice. Compensation rates and rating criteria are subject to change. Always verify current rates at VA.gov or consult with an accredited VSO, attorney, or claims agent before making decisions about your benefits.
Written by Claim Recon Editorial