How VA Combined Ratings Work: Why 70% + 40% Doesn’t Equal 110%
Posted by Gregory M. Rada | June 21, 2026 | Disability Compensation
If you have a 70% rating for PTSD and a 40% rating for a back condition, your combined VA disability rating is not 110%. It’s not even 100%. Under VA’s combined ratings formula, those two ratings produce a combined value of 82%, which rounds to 80%. Most veterans discover this for the first time when they receive a rating decision and the numbers don’t add up. The system feels broken, but it’s working exactly as designed. Understanding how VA calculates combined ratings, and knowing when to stop chasing a higher combined rating and pursue TDIU instead, can save you years of frustration and potentially thousands of dollars in monthly compensation.
Table of Contents
- How VA Math Works
- Step-by-Step Example
- Why It Gets Harder as You Go Higher
- The Bilateral Factor
- When to Stop Chasing a Higher Combined Rating
- TDIU: The Faster Path to 100% Compensation
How VA Math Works
VA does not add your disability ratings together. Instead, it uses a combining formula laid out in 38 C.F.R. § 4.25 that operates on the concept of remaining “efficiency.” The idea is that a person cannot be more than 100% disabled. Each successive disability rating is applied not to the whole person, but to the portion of the person that is still considered “efficient” (healthy) after accounting for all previous disabilities.
Here’s the logic. If you have a 60% disability, VA considers you 40% efficient. Your next disability rating is applied to that remaining 40%, not to the original 100%. A second disability rated at 30% is 30% of that remaining 40%, which equals 12%. So your combined disability is 60% + 12% = 72%, not 60% + 30% = 90%.
After all disabilities are combined, VA rounds the result to the nearest number divisible by 10. Values ending in 5 round up. So a combined value of 72% rounds to 70%. A combined value of 75% rounds to 80%. A combined value of 94% rounds to 90%, not 100%. That rounding can have a massive impact on monthly compensation.
Step-by-Step Example
Let’s walk through a realistic scenario. A veteran has four service-connected conditions: PTSD at 50%, a back condition at 40%, radiculopathy in the left leg at 20%, and tinnitus at 10%.
Using regular math: 50 + 40 + 20 + 10 = 120%. But VA math works differently.
Start with the highest rating. PTSD at 50% means the veteran is 50% disabled and 50% efficient. Apply the next highest rating (40% for the back) to the remaining efficiency. 40% of 50% = 20%. The combined value is now 70%, with 30% efficiency remaining. Apply the next rating (20% for radiculopathy) to the remaining 30%. 20% of 30% = 6%. Combined value is now 76%, with 24% efficiency remaining. Apply the final rating (10% for tinnitus) to the remaining 24%. 10% of 24% = 2.4%. Combined value is now 78.4%.
VA converts 78.4% to a whole number (78%) and rounds to the nearest 10. The final combined rating is 80%.
That veteran has conditions totaling 120% under regular math but receives an 80% combined rating from VA. The monthly compensation difference between 80% and 100% for a single veteran in 2026 is over $1,800 per month.
Why It Gets Harder as You Go Higher
The combining formula creates a diminishing returns problem. The higher your existing combined rating, the less impact each new condition has. This is because each additional disability is applied to a shrinking pool of remaining efficiency.
Consider a veteran already at a combined 80%. They have 20% efficiency remaining. If they receive service connection for a new condition rated at 30%, that 30% is applied to the remaining 20%, adding only 6%. The combined value goes from 80% to 86%, which rounds to 90%. A 30% rating, which would feel significant on its own, moved the combined rating by only one step (80% to 90%).
Now consider what it takes to go from 90% to 100%. At 90%, the veteran has only 10% efficiency remaining. To reach a combined value of 95% (which rounds to 100%), the veteran would need a new condition or increase that covers at least half of that remaining 10%. In practice, that means a new rating of at least 50% on top of an already-90% combined rating. For most veterans, that’s simply not realistic through the schedular system alone.
This is the mathematical wall that veterans hit. The system is designed so that approaching 100% through combined ratings alone becomes increasingly difficult with each additional condition. Veterans who are at 80% or 90% and can’t work often spend years pursuing incremental rating increases when a different path would get them to 100% compensation much faster.
The Bilateral Factor
There is one exception to the standard combining formula that can help certain veterans: the bilateral factor under 38 C.F.R. § 4.26. When a veteran has service-connected disabilities affecting both arms, both legs, or paired skeletal muscles, VA combines the ratings for those bilateral conditions first, then adds 10% of the combined value before combining with the remaining disabilities.
For example, a veteran with a right knee condition rated at 10% and a left knee condition rated at 10% would first combine those two ratings under VA math (10% + 10% = 19%). Then the bilateral factor adds 10% of 19%, which is 1.9%, producing a bilateral combined value of 20.9% (rounded to 21% for further combining). That 21% is then combined with the veteran’s other disabilities.
The bilateral factor provides a small but meaningful boost. It doesn’t change the fundamental math problem at higher combined ratings, but it can be the difference between rounding up and rounding down, which in turn can affect eligibility for benefits like TDIU. If you have disabilities affecting paired extremities and your rating decision doesn’t reflect the bilateral factor, that may be an error worth reviewing.
VA also implemented an exception effective April 2023 providing that if applying the bilateral factor would actually lower a veteran’s combined rating (a rare edge case), VA will exclude those disabilities from the bilateral calculation and combine them separately to produce the more favorable result.
When to Stop Chasing a Higher Combined Rating
Many veterans spend years filing claim after claim, trying to add new conditions or increase existing ratings, hoping to eventually reach 100% through the combined ratings table. For some veterans, that approach makes sense. But for veterans who are at 70%, 80%, or 90% and can’t work because of their service-connected conditions, the math is often working against them.
The gap between 90% and 100% is worth over $1,500 per month for a single veteran. But reaching a true schedular 100% from 90% is extremely difficult because of how the combining formula works. Meanwhile, TDIU pays at the same 100% rate and requires only a showing that service-connected disabilities prevent substantially gainful employment.
The question veterans should ask is not “how do I get to 100% through ratings?” but rather “am I unable to work because of my service-connected conditions?” If the answer is yes, TDIU may be available regardless of whether the combined rating reaches 100% through the table.
TDIU: The Faster Path to 100% Compensation
TDIU pays at the 100% rate ($3,938.58 per month for a single veteran in 2026) without requiring a 100% combined schedular rating. Under 38 C.F.R. § 4.16(a), a veteran may qualify for TDIU with a single condition rated at 60% or higher, or a combined rating of 70% with at least one condition rated at 40% or higher. Veterans who don’t meet those thresholds may still qualify through extraschedular TDIU under § 4.16(b).
Consider the veteran from our earlier example: 50% for PTSD, 40% for a back condition, 20% for radiculopathy, 10% for tinnitus, with a combined rating of 80%. That veteran meets the schedular TDIU thresholds (combined 70% or higher, with at least one condition at 40%). If service-connected conditions prevent them from maintaining substantially gainful employment, they may be eligible for TDIU, which would pay at the 100% rate. The monthly increase from 80% to the TDIU/100% rate is over $1,800.
That same veteran could spend years trying to get the combined rating from 80% to 100% through the table. Or they could pursue TDIU based on the conditions they already have. For many veterans, TDIU is the more practical path.
There are also situations where secondary service connection claims can help a veteran both increase their combined rating and strengthen a TDIU case simultaneously. A veteran who develops depression secondary to chronic pain, for example, may receive an additional mental health rating that pushes the combined number higher while also providing stronger evidence of occupational impairment for TDIU purposes.
Understanding the math is the first step. Knowing when to shift strategy from chasing a higher combined rating to pursuing TDIU is the step that often makes the biggest financial difference.
At After Service, we evaluate every veteran’s ratings, combined percentage, and employment situation to determine the most effective path to maximum compensation. In many cases, TDIU produces a better result faster than pursuing additional schedular increases. We also review effective dates to make sure that when TDIU is granted, the veteran receives the full retroactive pay they’re owed.
If your combined rating is 70% or higher but less than 100%, and you can’t work because of your service-connected conditions, contact After Service LLC for a free consultation. We represent veterans nationwide and can evaluate whether TDIU or another strategy is the right path for your situation. Call us at 800-955-8596 or schedule a free consultation today.
