When calculating combined disability ratings, the VA does not use regular math. Instead of simply adding up the percentage disability ratings for various conditions to reach a grand total disability rating, the VA takes percentages of percentages.
VA Disability Benefits include tax-free monetary compensation and other benefits, depending on the VA Disability Rating. The VA’s calculations use a percentage of the Veteran’s remaining non-disabled percentage when adding the next disability percentage. For example, if a veteran had three disabling conditions rated at 30%, 20% and 20%, the VA would first apply the largest percentage, 30%.
To factor in the next percentage, it would not simply add 20 to 30 and get 50. Rather, it would apply the 20% to the Veterans remaining 70% of non-disability. The resulting 14% would be added to the current rating of 30%, creating a total of 44%. If these were the only two disabilities on hand, this would get rounded down and the Veteran would receive a total disability of 40%.
Next, the third disability rating, 20%, would be applied to the remaining 56% (100%-44%). This would result in an individual rating of 11%. This would then be added to the total of 44%, generating a total disability rating of 55%. This number would then be rounded up, producing the combined disability rating of 60%. “Normal” math would have reached a 70% disability rating instead.
If all of this seems more than a bit confusing to you, rest assured that you are not alone. That’s why we have provided the calculator above to help you get a better idea of how your disability ratings add up using VA math. Keep in mind that this tool should be used only to get a general idea of how disability ratings are combined.