VA Math Examples for Veterans

VA math is the source of more veteran confusion than almost any other aspect of the claims process. Veterans who expect their ratings to add together arithmetically often feel cheated when the VA's combined rating comes in lower. Understanding the math through worked examples clarifies why this happens and reveals strategic insights for planning claims.

This guide presents eight detailed examples covering the most common scenarios, with formula math shown step-by-step. Each example also discusses the compensation impact and what it implies for claim strategy.

01
The Formula in 30 Seconds

Combined Rating = 100% minus [(100% minus rating 1) × (100% minus rating 2) × ... × (100% minus rating N)]

Always start with the highest rating. Each disability applies to the REMAINING capacity after prior disabilities, not the original 100%. Round the final result to the nearest 10% (5-9 rounds up, 0-4 rounds down).

For paired body parts (both arms, both legs, both eyes, both ears), combine them first, then multiply by 1.10 for the bilateral factor, then continue with other ratings.

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Example 1: Simple Two-Condition

Ratings: 50% PTSD, 30% lower back

Math:

• 100% minus [(100% minus 50%) × (100% minus 30%)]
• 100% minus [50% × 70%]
• 100% minus 35%
• = 65%
• Rounded to nearest 10%: 65 → 70

Final: 70%. Pay 2026 (single vet): $1,808.45/month.

Naive addition gives 80% = $2,102.40/month. Difference: $294/month for the rest of the veteran's life. This is "VA math" at work.

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Example 2: Borderline Rounding

Ratings: 40% PTSD, 20% knee, 10% tinnitus

Math:

• Start with 40%. Remaining: 60%.
• Apply 20% to 60%: 20% × 60% = 12%. Combined: 52%. Remaining: 48%.
• Apply 10% to 48%: 10% × 48% = 4.8%. Combined: 56.8%.
• Rounded: 56.8 → 60%.

Final: 60%. Now what if the 20% knee had been 30%?

• Start with 40%. Remaining: 60%.
• Apply 30% to 60%: 18%. Combined: 58%. Remaining: 42%.
• Apply 10% to 42%: 4.2%. Combined: 62.2%.
• Rounded: 62.2 → 60%.

Same final 60% rating! That extra 10% on the knee added 6 percentage points to the raw combined value (56.8 → 62.2) but did not move the rounded rating. This illustrates how rounding swallows small differences. Conversely, a single point pushing a value from 54.9 to 55 changes rounding from 50% to 60%, a $300+/month difference.

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Example 3: Diminishing Returns Effect

Ratings: 70% PTSD, 30% back, 20% tinnitus, 10% shoulder, 10% knee

Math:

• Start with 70%. Remaining: 30%.
• Apply 30%: 30% × 30% = 9%. Combined: 79%. Remaining: 21%.
• Apply 20% to 21%: 4.2%. Combined: 83.2%. Remaining: 16.8%.
• Apply 10% to 16.8%: 1.68%. Combined: 84.88%. Remaining: 15.12%.
• Apply 10% to 15.12%: 1.51%. Combined: 86.39%. Remaining: 13.61%.
• Rounded: 86.39 → 90%.

Final: 90%. Five separate service-connected conditions, naive total 140%, VA math 86%, rounded 90%.

Notice the diminishing returns: each subsequent low-percent rating adds less and less to the combined total. The fourth and fifth conditions (10% each) added only 3 percentage points combined to a base of 83%.

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Example 4: Bilateral Factor Boost

Ratings: 50% PTSD, 20% right knee, 20% left knee, 10% lumbar

Math:

• Combine the bilateral pair first: 20% + 20%. Using formula: 100% minus (80% × 80%) = 100% minus 64% = 36%.
• Apply 10% bilateral factor: 36% × 1.10 = 39.6%. Use as effective single 40%.
• Now combine with non-bilateral ratings, highest first: 50%, 40% (effective bilateral), 10%.
• Start with 50%. Remaining: 50%.
• Apply 40% to 50%: 20%. Combined: 70%. Remaining: 30%.
• Apply 10% to 30%: 3%. Combined: 73%.
• Rounded: 73 → 70%.

Final: 70%. Compare WITHOUT bilateral factor: 50% + (36% × 50%) = 68%, then 10%: 68% + (10% × 32%) = 71.2%, rounds to 70%. Same final answer this time. But on borderline cases, the bilateral factor's 10% can push the rating from 60% to 70% or 80% to 90%.

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Example 5: 70% to 80% via Secondary

Starting: 70% PTSD. Adding: 30% depression (secondary to PTSD).

Math:

• Start with 70%. Remaining: 30%.
• Apply 30% to 30%: 9%. Combined: 79%.
• Rounded: 79 → 80%.

Final: 80%. Pay change: $1,808.45 → $2,102.40/month (single vet). That's $294/month more, or $3,528 per year, from a single secondary condition claim. Secondary conditions are often the most efficient path to higher ratings because the evidentiary burden (nexus to existing service-connected condition) is lower than for primary service connection.

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Example 6: Why 100% Schedular Is Hard

Starting: 70% PTSD, 50% diabetes, 40% sleep apnea, 30% back, 20% tinnitus

Math:

• Start with 70%. Remaining: 30%.
• Apply 50% to 30%: 15%. Combined: 85%. Remaining: 15%.
• Apply 40% to 15%: 6%. Combined: 91%. Remaining: 9%.
• Apply 30% to 9%: 2.7%. Combined: 93.7%. Remaining: 6.3%.
• Apply 20% to 6.3%: 1.26%. Combined: 94.96%.
• Rounded: 94.96 → 90%.

Final: 90%. Five substantial service-connected conditions and the veteran is still at 90%, not 100%. To reach 100% schedular, the veteran would need a single condition at 100% rating, OR additional substantial conditions pushing the combined to 95%+ before rounding.

This is the math reason TDIU is often more practical than 100% schedular for veterans with multiple conditions.

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Example 7: TDIU vs Schedular

Veteran with 70% combined rating who cannot maintain substantially gainful employment.

• Schedular 70% (single vet, 2026): $1,808.45/month
• TDIU at 70% (paid at 100% rate, single vet, 2026): $3,938.58/month
• Difference: $2,130.13/month, or $25,562/year

TDIU eligibility under 38 CFR § 4.16: One disability rated 60%, OR combined 70% with at least one disability at 40%, AND the veteran cannot maintain substantially gainful employment due to service-connected conditions (income threshold ~$15,650/year in 2026). For veterans with chronic work-impacting conditions, TDIU should always be explored.

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Example 8: Sweet Spot at 70% Mental Health

Many veterans observe a "sweet spot" at 70% mental health rating because:

• 70% mental health requires occupational and social impairment with deficiencies in most areas
• This level alone often meets TDIU eligibility (one disability at 60% or higher)
• Plus 70% as the base for combined rating allows additional conditions to push toward 100%
• Pursuing 100% mental health requires "total occupational and social impairment" which is the highest bar

For many veterans, the strategic path is: reach 70% mental health, claim TDIU based on inability to work, receive 100% pay while continuing to develop additional secondary conditions for full 100% schedular protection.

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Patterns That Emerge

Across the examples, several patterns emerge:

• Diminishing returns: Each subsequent rating adds less than the previous because it applies to remaining capacity
• Rounding cliffs: The 5-percentage-point boundary (e.g. 64% vs 65%) can mean $300+/month difference
• Low-percent ratings rarely move ratings already at 70%+: A 10% addition to a 70% base only adds 3 raw percentage points
• Bilateral factor boost is real: Especially impactful for veterans with paired-limb conditions
• Secondary conditions are efficient: Lower evidentiary burden, can push from 70% to 80% with a single 30% secondary
• 100% schedular is mathematically hard: Often requires single 100% condition or 5+ high-percent conditions
• TDIU often the practical 100% path: 70% with unemployability pays at 100% rate

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Strategic Takeaways

• Focus on high-percent claims when you're already at 60-70%
• Pursue secondary conditions aggressively as efficient path to higher ratings
• File bilateral pairs together to trigger the 10% bilateral factor
• Check the rounding cliff on your current combined rating; small evidence might push you to next bracket
• Consider TDIU if you're at 70% and unable to maintain substantially gainful employment
• Use the calculator before filing to estimate which claims will actually move your rating
• Document everything: precise ratings, dates, and dependency status

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Frequently Asked Questions

VA Claims US Editorial Team

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The VA Claims US editorial team is dedicated to helping veterans and their families understand and navigate the VA disability system. Our content is reviewed for accuracy against current VA regulations and updated whenever rates or policies change. Have a question? Contact us here.