VA Combined Rating Calculator: How the Math Actually Works

Why VA Math Is Not Regular Math

One of the most frustrating aspects of the VA disability system is that combined ratings do not use simple addition. If you have a 50% rating for your back and a 30% rating for your knee, your combined rating is not 80%. Under the VA's "whole person" theory, codified in 38 CFR 4.25, your body starts at 100% healthy. Each disability takes a percentage of your remaining healthy body, not a percentage of the total. Understanding this math is essential for strategizing your claims and knowing what your combined rating will actually be.

Step-by-Step: How the Calculation Works

Here is how the VA calculates a combined rating, step by step:

Example: A veteran with three rated conditions: 50%, 30%, and 20%.

• Step 1: Start with 100% (your whole, healthy body).
• Step 2: Apply the highest rating first. 50% of 100 = 50. Your remaining healthy body is 100 - 50 = 50%.
• Step 3: Apply the next highest rating to the remaining healthy body. 30% of 50 = 15. Your remaining healthy body is 50 - 15 = 35%.
• Step 4: Apply the next rating to the remaining healthy body. 20% of 35 = 7. Your remaining healthy body is 35 - 7 = 28%.
• Step 5: Your combined disability is 100 - 28 = 72%.
• Step 6: Round to the nearest 10. 72% rounds to 70%.

With simple addition, 50 + 30 + 20 = 100%. With VA math, the same three ratings combine to 70%. This is why veterans often feel their combined rating does not match the severity of their conditions.

Rounding Rules: Where 5% Becomes 10%

The VA rounds the final combined value to the nearest 10%. The rounding rule uses standard mathematical rounding: combined values ending in 5 or higher round up, values ending in 4 or lower round down. This means:

• A combined value of 74% rounds down to 70%
• A combined value of 75% rounds up to 80%
• A combined value of 94% rounds down to 90%
• A combined value of 95% rounds up to 100%

Strategic Insight: This rounding rule means that a small additional condition can have an outsized impact on your final rating. If your combined value before rounding is 73%, adding even a 10% condition could push you to 76%, which rounds up to 80%. That 10% condition just gave you a 10% jump in your final rating.

The Bilateral Factor (38 CFR 4.26)

The bilateral factor is a small but meaningful bonus that applies when you have disabilities affecting both sides of your body (bilateral conditions). Under 38 CFR 4.26, when you have paired conditions affecting both extremities (both knees, both shoulders, both feet, etc.), the VA adds 10% of the combined value of those bilateral conditions before incorporating them into the overall combined rating.

Example: If you have 20% for your left knee and 10% for your right knee:

• Combined value of bilateral conditions: 28% (using VA math: 20 + 10% of 80 = 28)
• Bilateral factor bonus: 10% of 28 = 2.8, rounded to 3
• Adjusted bilateral value: 28 + 3 = 31%

This 31% is then combined with your other non-bilateral conditions using the standard VA math process. The bilateral factor is applied automatically by the VA, but knowing about it helps you understand why your combined rating might be slightly higher than expected.

Strategic Implications for Your Claims

Understanding VA math has real strategic implications for how and when you file claims:

• Higher individual ratings matter more than many small ones. Because each subsequent condition is applied to a smaller remaining percentage, getting a 50% rating for one condition is worth more than getting five 10% ratings. Focus on getting your most severe conditions rated accurately first.
• Threshold crossings are valuable. The compensation jumps between rating levels are significant. Going from 60% to 70% is a meaningful monthly increase. Going from 90% to 100% is the largest single jump. Know where your current combined value sits relative to the next threshold and target claims that push you across.
• Even a 10% condition can change everything. If your combined value is sitting just below a rounding threshold (such as 73% or 74%), adding a single 10% condition can push you up an entire rating level. Never dismiss a claimable condition as "too small to matter."
• TDIU is an alternative path to 100%. If your combined rating is 60% or higher (with at least one condition at 40%+), or 70% overall, and your disabilities prevent you from maintaining substantially gainful employment, you may qualify for Total Disability based on Individual Unemployability (TDIU). TDIU pays at the 100% rate even if your combined rating is lower.

Real-World Example Scenarios

Scenario 1: The Power of One More Condition

Veteran has PTSD at 70% and a back condition at 20%. VA math: remaining = 100 - 70 = 30. Then 30 - (20% of 30) = 30 - 6 = 24. Combined disability: 76%, rounds to 80%. Now they file for tinnitus (10%): 24 - (10% of 24) = 24 - 2.4 = 21.6. Combined: 78.4%, still rounds to 80%. But if they also file for GERD (10%): 21.6 - (10% of 21.6) = 21.6 - 2.16 = 19.44. Combined: 80.56%, still rounds to 80%. The lesson: once you cross a threshold, additional small claims may not push you to the next one without a larger condition in the mix.

Scenario 2: Strategic Addition of Sleep Apnea

Veteran has a combined value of 68% (rounds to 70%). They are diagnosed with sleep apnea secondary to PTSD (50% rating with CPAP). New calculation: remaining was 32%. Sleep apnea: 32 - (50% of 32) = 32 - 16 = 16. New combined: 84%, rounds to 80%. That single 50% condition jumped them from 70% to 80%, adding over $400 per month in compensation.

Ready to Get Your Rating Reviewed?

Stop guessing and start calculating. Use our VA Disability Calculator to input all your current and potential conditions and see exactly what your combined rating would be. It handles all the VA math, bilateral factor, and rounding for you. Then use our free AI-powered claim analysis to identify additional conditions you may be entitled to claim. Every percentage point matters, and knowing the math helps you claim strategically.

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