🧮 How VA Combined Ratings Work

TDIU = Total Disability Individual Unemployability — pays at the 100% rate if your conditions prevent gainful employment, even without a 100% combined rating. Bilateral factor = a small bonus applied before combining when conditions affect both sides of the body (both knees, both arms, etc.).

Almost every veteran with multiple conditions is surprised by their combined disability rating. If you have a 50% rating and a 30% rating, you expect 80%. The VA gives you 65%. This is not an error. It is the VA's "whole person" formula. Understanding how it works is essential to knowing whether you should file for TDIU or additional conditions.

How the Formula Works

The VA treats you as starting with a 100% healthy body. Each disability is calculated against the remaining healthy portion, not against 100%.

Example 1: 50% + 30%

• 50% disability → 50% remaining
• 30% applied to 50% remaining = 15%
• Combined total: 50 + 15 = 65%
• VA rounds to nearest 10%: 60%

Example 2: 50% + 50%

• First 50% → 50% remaining
• Second 50% of 50% remaining = 25%
• Combined total: 50 + 25 = 75%
• VA rounds to nearest 10%: 70%

Example 3: 40% + 20% + 20%

• 40% → 60% remaining
• 20% of 60% remaining = 12% → running total: 52%
• 20% of 48% remaining = 9.6% → total: 61.6%
• VA rounds to nearest 10%: 60%

Why This Matters

TDIU Threshold — To qualify for TDIU (which pays at the 100% rate), you need either one condition rated 60% or higher, OR a combined rating of 70% or higher with at least one condition at 40%+. Many veterans are close to these thresholds without realizing it. Adding a secondary condition could push you over.

100% Combined Is Essentially Impossible — Because each new condition is applied to a shrinking healthy remainder, reaching a true 100% combined rating through conditions alone would require nearly complete incapacity across all body systems. TDIU is the pathway most veterans should pursue if they cannot work.

Bilateral Factor — Conditions affecting both sides of the body (both knees, both arms, both ears) get a bilateral factor added before combining — this slightly increases the combined rating. Ask your VSO whether any of your conditions qualify.

What to Do

1. List every condition and rating. Look at your rating decision letter and write down every service-connected condition and its individual percentage rating.
2. Check the TDIU threshold. Are you near 70% combined with one condition at 40%+, or near 60% on a single condition? If you are close, filing one additional secondary condition may push you over.
3. File for TDIU if you cannot work. Use VA Form 21-8940 regardless of your current combined rating. The VA can grant TDIU on an extraschedular basis even without meeting the standard thresholds if circumstances are exceptional.
4. Use the VA's combined ratings calculator. Enter your conditions and ratings at va.gov to see the exact combined result before meeting with your VSO.

Calculate My Ratingva.gov/disability/about-disability-ratings/ DAV — Free Claims Help877-838-6827 · No cost to veterans