# The VA math: how ratings combine into one number

VA combines disability ratings instead of adding them under [38 CFR §4.25](https://www.ecfr.gov/current/title-38/section-4.25). The bilateral factor is addressed in [38 CFR §4.26](https://www.ecfr.gov/current/title-38/section-4.26).

## Worked example: 60%, 40%, and 20%

1. **Whole, healthy person**
   Start at 100% efficiency. Each rating is applied to what is left, not to the whole.
2. **Apply your worst first, 60%**
   Combine ratings from most severe to least. A 60% rating uses 60 of 100 points, leaving 40% efficiency.
3. **Combine 40%**
   Apply the 40% rating to the 40% efficiency that remains. The combined ratings table records the result as 76%.
4. **Combine 20%**
   Apply the 20% rating to the 24% efficiency that remains. The combined ratings table records the result as 81%.
5. **Bilateral factor, checked, not applied**
   The bilateral factor applies to paired left-and-right limbs. It does not apply when the rated conditions are not a left-and-right pair.
6. **Round once, at the end, 80%**
   Round the final combined figure to the nearest 10 only once, at the end. In this example, 81% rounds down to 80%.

The worked combination reaches 81%, which rounds once at the end to an 80% combined evaluation.

Educational only. [View the HTML explanation](/the-va-math).