VA Combined Rating Math Explained
This is the question veterans ask more than almost any other.
"I have 70% for PTSD and 30% for my knee. Why is my rating 80% instead of 100%?"
The answer is that the VA does not add disability ratings together. It has never added them together. It uses a formula that produces results that are always lower than simple addition, sometimes significantly lower.
Understanding this formula is not optional if you want to maximize your benefits. It tells you exactly where you stand. It shows you which conditions are worth pursuing. It shows you when you are close to a rounding threshold that could be worth hundreds of dollars per month.
The Concept: Remaining Efficiency
The whole person method is built on one idea. You start at 100% functional efficiency. Every disability reduces what is left.
Think of it this way. If you are 70% disabled, the VA considers 30% of you to still be functional. A second disability does not apply to the full 100%. It applies to that remaining 30%.
That is the core logic. Each condition chips away at what is left, not at the original whole.
The Formula
The official formula from 38 CFR 4.25 is:
Combined Rating = 1 - (1 - D1)(1 - D2)(1 - D3)...
Where D1, D2, D3 are individual ratings expressed as decimals, sorted from highest to lowest.
In plain terms: take the complement of each rating (100% minus the rating), multiply those complements together, and subtract the result from 100%.
The result is your raw combined rating. Round to the nearest 10% and you have your official VA rating.
Four Real Examples
Example 1: The Classic "70 Plus 30"
Veteran has PTSD at 70% and a knee at 30%.
Apply 70% to 100% efficiency. 30% remains. Apply 30% to that remaining 30%. That adds 9%. Raw combined: 79%. Round to nearest 10%: 80%.
Not 100%. Not even 90%. 80%.
Example 2: Two 50% Ratings
Veteran has sleep apnea at 50% and tinnitus at 50%.
Apply first 50% to 100% efficiency. 50% remains. Apply second 50% to remaining 50%. That adds 25%. Raw combined: 75%. Round to nearest 10%: 80%.
Simple addition said 100%. VA math says 80%.
Example 3: Three Conditions
Veteran has PTSD at 70%, sleep apnea at 50%, tinnitus at 10%.
Apply 70% to 100% efficiency. 30% remains. Apply 50% to remaining 30%. That adds 15%. Running total: 85%. 15% remains. Apply 10% to remaining 15%. That adds 1.5%. Running total: 86.5%. Round to nearest 10%: 90%.
Monthly pay at 90% with no dependents in 2026: $2,362.30.
Example 4: Why Order Matters
The formula requires sorting highest to lowest. This is not arbitrary. Applying the largest rating first produces the lowest remaining efficiency for subsequent conditions, which is mathematically correct.
If you apply conditions in the wrong order you get a different raw combined. The VA always applies them highest first.
The Rounding Threshold: The Most Important Number You Do Not Know
Your official rating is your raw combined rounded to the nearest 10%. That means:
Raw combined 45.0% to 54.9% rounds to 50%
Raw combined 55.0% to 64.9% rounds to 60%
Raw combined 65.0% to 74.9% rounds to 70%
Raw combined 75.0% to 84.9% rounds to 80%
Raw combined 85.0% to 94.9% rounds to 90%
The distance between where you are and the next rounding threshold is the number that should drive your claims strategy.
If your raw combined is 74.2%, you are at 70% rounded. You need 0.8 more raw points to cross 75% and round to 80%. A new condition at 10% adds 2.58 raw points to a 74.2% combined. That crosses the threshold. Monthly pay at 80% in 2026 is $2,102.15 versus $1,808.45 at 70%. That is $293.70 more per month, $3,524.40 per year, tax-free.
The Bilateral Factor
When you have rated conditions on both sides of a paired extremity, the bilateral factor under 38 CFR 4.26 adds a bonus before those combined conditions enter your overall calculation.
The VA first combines your bilateral conditions together. It then multiplies that combined value by 10% and adds the result. That adjusted subtotal enters your overall combined rating calculation as a single number.
For example: right knee at 20%, left knee at 10% combine to 28%. The bilateral factor adds 2.8%. Bilateral subtotal: 30.8%. That 30.8% then combines with your other conditions.
The bilateral factor does not show up as a separate payment. But it can be the 0.8 points that pushes a raw combined from 74.2% to 75% and earns you an extra $3,524 per year.
Common Mistakes Veterans Make Calculating Their Own Rating
Adding the percentages. Cannot be said enough. VA math is not addition. Stop at the first step if you catch yourself adding.
Forgetting to sort. Always apply highest rating first. Applying them in a different order produces a wrong result.
Forgetting the bilateral factor. If you have conditions on both extremities and you are not accounting for the bilateral factor, your manual calculation is missing a bonus.
Using the rounded number to calculate the next step. All intermediate math uses the raw combined, not the rounded number. Your running total after the first two conditions might be 78.4%, not 80%. Apply the third condition to the raw 78.4%, not to 80.
Rounding too early. Only round once, at the very end.
Verify Your Own Rating
Use the calculator at the top of this page to enter your conditions and see your raw combined alongside your rounded rating. If your calculation does not match your official rating, check whether the bilateral factor was applied and whether all conditions were included.
If you find a discrepancy, a supplemental claim or appeal may be appropriate.
Get a free rating review from a VA-accredited attorney.
No upfront cost. No fee unless you win.
Frequently Asked Questions
Why does the VA use the whole person method instead of adding ratings together?
The VA uses the whole person method instead of simple addition because simple addition produces mathematically impossible results when multiple high ratings are combined. A veteran with four 50% ratings would have a 200% combined rating under simple addition, which is meaningless because disability cannot exceed total functional capacity. The whole person method prevents this by applying each subsequent rating only to the healthy portion that has not already been claimed as disabled. The formula is defined in 38 CFR 4.25 and has been the standard for VA disability calculations for decades. While it consistently produces lower results than simple addition, it also ensures that the combined rating accurately reflects the cumulative functional impact of multiple disabilities without exceeding 100%.
What is the rounding rule for VA disability ratings?
The VA rounds the raw combined disability rating to the nearest 10% to determine the official rating used for compensation purposes. A raw combined rating between 45% and 54% rounds down to 50%. A raw combined between 55% and 64% rounds up to 60%. This pattern continues through all rating levels. A raw combined of exactly 45% rounds up to 50%, while a raw combined of 44.9% rounds down to 40%. The rounding step is significant because it determines which compensation tier the veteran falls into, and the monthly difference between adjacent tiers ranges from $166 to $1,576 in 2026. Veterans whose raw combined sits just below a rounding threshold should identify whether an additional condition could push them across.
Does the order of conditions affect the VA combined rating?
Yes. The VA whole person method requires applying disability ratings from highest to lowest. Applying the highest-rated condition first produces the correct mathematical result because it creates the smallest remaining efficiency for subsequent conditions. If conditions are applied in a different order, the raw combined will differ. The statutory formula at 38 CFR 4.25 specifies the descending order requirement. In practice, the VA combined ratings table sorts conditions before calculating. Veterans calculating their own combined rating should always start with the highest percentage, apply it to 100%, and work downward from there. The bilateral factor subtotal, if applicable, is calculated separately and enters the main calculation as a single number, combined with non-bilateral conditions from highest to lowest among all remaining values.
Can I reach 100% combined rating through multiple conditions?
Yes, but it requires many high-rated conditions because the whole person method produces diminishing returns as the combined rating climbs. Each new condition applies to a shrinking remainder. A veteran with 70% PTSD and 50% sleep apnea has an 85% raw combined, which rounds to 90%. Adding a 30% hypertension condition takes that to 89.5%, which still rounds to 90%. Adding another condition at 20% takes the raw combined to 91.6%, which rounds to 90%. Reaching 95% raw combined, where the result rounds to 100%, requires additional high-rated conditions. Many veterans reach 90% combined but cannot reach 100% schedular. For those veterans, TDIU is the pathway to 100% pay rate if their conditions prevent substantially gainful employment.
What is the bilateral factor and how much does it add to my rating?
The bilateral factor is an addition defined in 38 CFR 4.26 that applies when a veteran has service-connected disabilities affecting both upper extremities or both lower extremities. The VA combines the paired conditions first, then multiplies that combined value by 10% and adds the result back to the bilateral subtotal. For example, a right knee at 20% and left knee at 10% combine to 28%. Ten percent of 28 is 2.8. The bilateral subtotal becomes 30.8%, which enters the overall combined rating calculation. The factor does not create a separate payment but can push the final raw combined across a rounding threshold. Whether it matters in a specific case depends entirely on where the veteran's raw combined sits relative to the nearest 5% rounding midpoint. Use the bilateral factor calculator to see the exact impact on your numbers."
