TDIU: The One Place the Combined Rating Table Stops Being the Answer

The acronym is not in the rule. Search 38 CFR 4.16 for the four letters and you get zero hits. The section heading, verbatim, is: Total disability ratings for compensation based on unemployability of the individual.

TDIU is what veterans, raters and practitioners call it in conversation. That shorthand is useful right up to the moment somebody wants to read the actual text, at which point it stops matching anything. Knowing the real name is what gets a reader to the regulation instead of to a summary of it written by somebody with an interest in the summary.

A free accredited Veterans Service Organization representative can read the section with a veteran and go through what is in their file. VSOs are accredited by VA and they don't charge. That is the first route worth knowing about, before any other.

Everywhere else in rating math, the number follows from the table. Individual evaluations go into 38 CFR 4.25, Table I combines them in order of severity, and the result converts to a multiple of ten. The combined rating is whatever falls out of that process.

4.16 is the point where that stops being the whole answer. The first words of paragraph (a) are: Total disability ratings for compensation may be assigned, where the schedular rating is less than total. The section is written for the situation where the math has already produced something under 100 and the file describes something the math did not capture.

Compensation at the total rate is the 100 percent rate on VA's published rate table. For a veteran with no dependents, effective December 1, 2025, that rate is 3,938.58 per month.

Two branches, depending on how many service-connected disabilities are in play. The regulation states them as a proviso attached to the sentence above: "Provided That, if there is only one such disability, this disability shall be ratable at 60 percent or more, and that, if there are two or more disabilities, there shall be at least one disability ratable at 40 percent or more, and sufficient additional disability to bring the combined rating to 70 percent or more."

Read the second branch carefully, because it has two parts and both have to hold. One disability at 40 percent or more is the first. A combined rating of 70 percent or more is the second. A file can satisfy one and not the other.

The combined rating in that sentence is the figure after the conversion to a multiple of ten. 38 CFR 4.25(b) settles that: "The conversion to the nearest degree divisible by 10 will be done only once per rating decision, will follow the combining of all disabilities, and will be the last procedure in determining the combined degree of disability." The combined degree of disability is not determined until the conversion has happened, so that is the figure the 70 percent condition is written against.

Paragraph (a) also tells the rating agency what to ignore: "It is provided further that the existence or degree of nonservice-connected disabilities or previous unemployability status will be disregarded where the percentages referred to in this paragraph for the service-connected disability or disabilities are met and in the judgment of the rating agency such service-connected disabilities render the veteran unemployable."

This is the part of the section with real math in it, and it changes how the count works. The text: "For the above purpose of one 60 percent disability, or one 40 percent disability in combination, the following will be considered as one disability: (1) Disabilities of one or both upper extremities, or of one or both lower extremities, including the bilateral factor, if applicable, (2) disabilities resulting from common etiology or a single accident, (3) disabilities affecting a single body system, e.g. orthopedic, digestive, respiratory, cardiovascular-renal, neuropsychiatric, (4) multiple injuries incurred in action, or (5) multiple disabilities incurred as a prisoner of war."

What it does is let two or more separate evaluations be read together as one disability for the threshold test in that paragraph. Not for the combined rating on the decision letter. Only for the count in 4.16(a), which is what the opening words, for the above purpose, are doing there.

Take a file with two evaluations affecting one lower extremity, one at 30 percent and one at 20 percent. On the decision letter those are two separate evaluations. Under item (1) of this list they are considered as one disability for the paragraph (a) test, and combining them under 4.25 gives 100 minus (70 times 80 divided by 100), which is 44. Whether that 44 is read as 44 or converted to 40, it clears the 40 percent condition either way, so on these numbers the rounding question doesn't come up.

The bilateral factor is named inside item (1) and applies where the extremities on both sides are involved. Its own math is set out separately in 38 CFR part 4 and is not reproduced here.

Item (3) is the widest of the five. A single body system covers a lot of files, and the regulation gives five examples of what it means by one: orthopedic, digestive, respiratory, cardiovascular-renal, neuropsychiatric.

Unnamed conditions, four of them, so the math is the only thing on display. One condition evaluated at 40 percent, a second at 30 percent, a third at 20 percent, and a fourth at 10 percent.

38 CFR 4.25 directs that the disabilities be arranged in the exact order of their severity, beginning with the greatest, and then combined using Table I. So: 40, then 30, then 20, then 10. Every cell of Table I is the same calculation, 100 minus the product of the two remaining efficiencies over 100, rounded half up.

40 combined with 30 gives 58. 58 combined with 20 gives 66.4, which is 66. 66 combined with 10 gives 69.4, which is 69. The conversion to a multiple of ten happens once, at the end, per 4.25(b): 69 converts to 70.

Now run the paragraph (a) conditions against those numbers. There are two or more disabilities, so the second branch applies. Is there at least one disability ratable at 40 percent or more? Yes, the 40. Is the combined rating 70 percent or more? Yes, 70, and only because the conversion happens last. The raw combined value before conversion was 69.

That 69 is worth sitting with, because it is where the two regulations meet. Read the combining as finished at 69 and the second condition in paragraph (a) is not satisfied. Read 4.25(b) the way it is written and the combined degree of disability is not determined until the conversion, which makes the figure 70.

On these numbers the percentages in paragraph (a) are met. That is the end of what the math can tell anyone.

The regulation defines it, and the definition is almost never quoted. Here it is in full: "Marginal employment shall not be considered substantially gainful employment. For purposes of this section, marginal employment generally shall be deemed to exist when a veteran's earned annual income does not exceed the amount established by the U.S. Department of Commerce, Bureau of the Census, as the poverty threshold for one person. Marginal employment may also be held to exist, on a facts found basis (includes but is not limited to employment in a protected environment such as a family business or sheltered workshop), when earned annual income exceeds the poverty threshold. Consideration shall be given in all claims to the nature of the employment and the reason for termination."

Three things in that passage do work. The first is the income benchmark: not a VA figure, but the Census Bureau poverty threshold for one person, which changes annually. The second is the phrase on a facts found basis, which opens a second path that does not run on income at all. The third is the parenthetical, which names a family business and a sheltered workshop as examples of a protected environment and says expressly that the examples are not the limit of it.

The last sentence applies to every claim, not only to marginal ones. The nature of the employment and the reason for termination are directed to be considered in all claims. A job that ended, and why it ended, is part of what the section tells the rating agency to look at.

It is a different kind of provision, not a second set of numbers. Paragraph (b) opens with a policy statement: "It is the established policy of the Department of Veterans Affairs that all veterans who are unable to secure and follow a substantially gainful occupation by reason of service-connected disabilities shall be rated totally disabled."

Then it gives rating boards a procedure. The text directs that they "should submit to the Director, Compensation Service, for extra-schedular consideration all cases of veterans who are unemployable by reason of service-connected disabilities, but who fail to meet the percentage standards set forth in paragraph (a) of this section."

The instruction runs to the rating board, and the submission goes up to the Director, Compensation Service. Paragraph (b) also specifies what has to go with it: "The rating board will include a full statement as to the veteran's service-connected disabilities, employment history, educational and vocational attainment and all other factors having a bearing on the issue."

The section ends there. There is no paragraph (c).

The percentages in 4.16(a) are a gate the regulation sets on the rating agency, and clearing that gate is not the decision. The decision is in the words the proviso is attached to: whether the person is, in the judgment of the rating agency, unable to secure or follow a substantially gainful occupation as a result of service-connected disabilities.

That judgment is made on the evidence in front of the agency. Employment history, what the medical record documents about function, what the section calls all other factors having a bearing on the issue. Numbers are the entry condition to that question, not an answer to it.

This page cannot say whether any of it applies to any particular veteran, and no page can. What a page can do is show where the rule actually lives, so the text is readable without an intermediary.