TDIU (Total Disability based on Individual Unemployability) is one of the most valuable, and most overlooked, benefits in the VA disability system. It lets you get paid at the 100% rate without needing a 100% combined schedular rating.
VA math (see the separate guide on combined ratings) makes it genuinely difficult to reach a 100% combined rating by stacking individual percentages. TDIU exists because the VA recognizes that the rating schedule doesn't always capture the real-world impact of a disability on someone's ability to actually hold a job. If your service-connected conditions prevent you from working, TDIU pays you as if you were rated 100%, even if your schedular rating is lower.
Schedular TDIU (under 38 CFR § 4.16(a)) requires meeting one of these rating thresholds:
Extraschedular TDIU (under 38 CFR § 4.16(b)) is for veterans who don't meet those thresholds but whose service-connected conditions still prevent them from working. These cases are referred to the VA's Director of Compensation and Pension Service for individual review, and the standard of evidence required is generally higher.
Meeting the rating percentages qualifies you to be considered for TDIU; it doesn't guarantee it. The actual question the VA asks is whether your service-connected disabilities prevent you from securing or maintaining "substantially gainful employment," meaning work that pays above the federal poverty threshold. This is decided on the evidence in your file: medical records, your employment history, income records, and the language in your C&P exam.
TDIU isn't a means test, there's no asset limit, and unearned income (investments, etc.) doesn't count against it. What matters is earned income from work. Earning above the substantial gainful activity threshold generally disqualifies you, though brief, unsuccessful work attempts are typically protected for a period rather than immediately ending your TDIU.
TDIU pays at the 100% compensation rate, but your official rating on paper stays whatever your combined schedular rating actually is (say, 70% or 80%). This distinction matters in a few contexts, and it's part of why TDIU is sometimes misunderstood, some veterans mistakenly believe a high combined rating already includes TDIU-level pay, when it doesn't unless TDIU has been separately granted.
TDIU is claimed using VA Form 21-8940, supported by:
The VA typically reviews TDIU cases periodically and may ask for updates on your employment status. If your circumstances change substantially (for example, you return to substantially gainful work), your TDIU status can be reevaluated.