If service-connected conditions keep you from holding steady work, you can be paid at the 100% rate without a 100% schedular rating.
Total Disability based on Individual Unemployability: TDIU, pays you at the 100% rate when your service-connected conditions prevent you from holding substantially gainful employment, even if your combined rating is below 100%.
The thresholds
Schedular TDIU generally requires one condition rated at 60%, or a combined 70% with at least one condition at 40%. If you do not meet those numbers, extraschedular TDIU is still possible on the facts.
Proving it
- Your work history and why the conditions ended it
- Medical evidence tying the limitations to service-connected conditions
- Sometimes a vocational expert opinion
“Substantially gainful” is the key phrase, marginal or sheltered work does not disqualify you. The VA can also match your reported income against SSA wage records, so the employment picture has to be documented honestly and completely.
The entire framework governing VA disability compensation is codified in Title 38 of the Code of Federal Regulations, with the rating schedule at 38 CFR Part 4 and the service-connection standards at §3.303 (direct), §3.310 (secondary), and §3.306 (aggravation). Raters adjudicate claims using the procedures in M21-1, the VA's internal manual that tells them exactly what evidence to develop, what exams to order, and how to apply the rating schedule. Under Gilbert v. Derwinski, when the evidence is in approximate balance, every doubt must be resolved in your favor. Under Caluza v. Brown, service connection requires three elements: a current disability, an in-service event, and a medical nexus linking the two, miss any one, and the claim fails.