Overview
One of the most confusing aspects of VA disability is how ratings combine. The VA does not simply add your individual ratings together. Instead, they use a specific formula often called "VA math."
How VA Math Works
The core principle: each rating is applied to the remaining "healthy" body, not the total.
The Formula
- Start with your highest individual rating
- Apply the next highest rating to the remaining percentage (what's left of your body the VA considers "healthy")
- Repeat for each additional rating
- Round to the nearest 10%
Example
Say you have three ratings: 50%, 30%, and 20%.
| Step | Rating | Remaining Healthy | Calculation | Combined | |------|--------|-------------------|-------------|----------| | Start | — | 100% | — | 0% | | 1 | 50% | 100% | 100% × 50% = 50% | 50% | | 2 | 30% | 50% | 50% × 30% = 15% | 65% | | 3 | 20% | 35% | 35% × 20% = 7% | 72% |
72% rounds up to 70% — that's your combined rating.
If you just added them: 50 + 30 + 20 = 100%. But VA math gives you 70%. This is why understanding VA math matters.
The Bilateral Factor
If you have disabilities affecting both sides of the body (e.g., both knees, both shoulders), the VA applies a bilateral factor — a 10% boost to those specific ratings before combining them with your other ratings.
This slightly increases your overall combined rating and is applied automatically.
Rounding Rules
- The combined value is always rounded to the nearest 10%
- 0.5 rounds up (e.g., 75% → 80%)
- Below 0.5 rounds down (e.g., 74% → 70%)
Why This Matters
Every 10% increment represents a significant change in monthly compensation. For example (2025 rates, veteran alone, no dependents):
| Rating | Monthly Payment | |--------|----------------| | 10% | $171.23 | | 30% | $524.31 | | 50% | $1,075.16 | | 70% | $1,716.28 | | 100% | $3,737.85 |
Note: Rates change annually. Check the current rates at VA.gov.
Key Takeaways
- The VA combines ratings using a "whole person" method, not simple addition
- Each additional rating has diminishing returns — the higher your existing combined rating, the less impact a new rating has
- The bilateral factor gives a small boost for conditions affecting matched body parts
- Understanding VA math helps you set realistic expectations and plan your claims strategically
What You Can Do
- Claim all legitimate conditions — even a 10% rating can push you to the next tier after rounding
- Don't forget secondary conditions — conditions caused by existing service-connected disabilities count too
- Use our Rating Calculator (coming soon) to estimate your combined rating before filing