How VA Combined Ratings Work (It's Not Simple Addition)

Bottom Line Up Front

VA disability ratings don't add up the way you'd expect. A 50% rating plus a 30% rating equals 65%, not 80%. The VA uses a "whole person" concept where each disability takes a percentage of your remaining capacity, not your original 100%. This system is codified in 38 CFR 4.25 and affects every veteran with multiple service-connected conditions. Understanding VA math is crucial because the difference between 60% and 70% is $355/month ($4,260/year), and many veterans are under-rated because they don't understand how to strategically file claims.

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Why VA Math Is Different

The VA doesn't simply add percentages together. Instead, they use a "combined ratings" formula based on the concept that you can only be 100% disabled once.

The Logic Behind It

Think of it this way: You start with 100% of your "whole person" capacity.

• Your first disability (say 50%) takes away 50% of your capacity
• You now have 50% capacity remaining
• Your second disability (say 30%) takes 30% of what's LEFT (50%), not 30% of the original 100%
• 30% of 50% = 15%
• So you're 50% + 15% = 65% disabled, not 80%

This is why veterans with multiple high ratings often feel their combined rating is "lower than it should be."

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The VA Combined Rating Formula

The Mathematical Formula

The official VA formula is:

Combined Rating = 100 - ((100 - rating1) × (100 - rating2) × ... / 100)

Step-by-Step Example: 50% + 30% + 20%

Let's walk through how the VA would combine three conditions rated at 50%, 30%, and 20%.

Step 1: Start with your highest rating first (50%)

• 100% whole person - 50% disability = 50% efficiency remaining

Step 2: Apply the next rating (30%) to what's left

• 30% of 50% remaining = 15% disability
• Running total: 50% + 15% = 65%
• Efficiency remaining: 35%

Step 3: Apply the third rating (20%) to what's left

• 20% of 35% remaining = 7% disability
• Running total: 65% + 7% = 72%

Final Combined Rating: 72%

The VA then rounds to the nearest 10%: 72% rounds to 70%

If you had simply added 50% + 30% + 20%, you'd expect 100%. But VA math gives you 70%.

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The Rounding Rules

The VA rounds your final combined rating to the nearest 10%:

Combined Rating	Rounds To
0-4%	0%
5-14%	10%
15-24%	20%
25-34%	30%
35-44%	40%
45-54%	50%
55-64%	60%
65-74%	70%
75-84%	80%
85-94%	90%
95-100%	100%

Key Insight: 0.5 and above rounds UP. So 64.5% rounds to 70%, but 64.4% rounds to 60%. This matters more than you might think.

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The Bilateral Factor: Extra 10% Bonus

What Is the Bilateral Factor?

When you have disabilities affecting BOTH sides of paired body parts (both knees, both shoulders, both legs, etc.), the VA applies a "bilateral factor" that adds 10% to your combined bilateral rating before combining with other conditions.

What Qualifies

• Both knees (even if different conditions)
• Both shoulders
• Both hips
• Both ankles
• Both arms/wrists
• Both legs (upper or lower)

Important: The conditions don't have to be identical. Right knee arthritis + left knee instability = bilateral factor applies.

How It's Calculated

1. Combine your bilateral conditions first
2. Add 10% of that combined value
3. Then combine that result with your non-bilateral conditions

Example:

• Right knee: 20%
• Left knee: 10%
• PTSD: 50%

Step 1: Combine bilateral conditions

• 20% + (10% of 80% remaining) = 28%

Step 2: Apply bilateral factor

• 28% + (10% × 28%) = 28% + 2.8% = 30.8%

Step 3: Combine with non-bilateral

• 30.8% combined with 50% PTSD = 65.4%

Final rating: 70% (after rounding)

Without bilateral factor, it would be 64% → rounded to 60%. That's a $355/month difference.

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Common VA Math Examples

Here are some real-world scenarios veterans encounter:

Example 1: Infantry Veteran (Musculoskeletal)

• Lower back: 40%
• Right knee: 20%
• Left knee: 10%
• Tinnitus: 10%

Calculation:

• Knees combined: 28% + bilateral factor (2.8%) = 30.8%
• 40% + 30.8% + 10% (tinnitus) using VA math = 63.5%
• Final: 60% ($1,361/month)

Example 2: Combat Veteran (PTSD + Physical)

• PTSD: 70%
• Sleep apnea: 50%
• Tinnitus: 10%

Calculation:

• 70% + (50% of 30% remaining) = 70% + 15% = 85%
• 85% + (10% of 15% remaining) = 85% + 1.5% = 86.5%
• Final: 90% ($2,241/month)

Example 3: The "Almost 100%" Trap

• PTSD: 70%
• Back: 40%
• Migraines: 30%
• Tinnitus: 10%

Simple addition: 150% VA math: 91% → Rounds to 90% (not 100%)

This is why reaching 100% schedular is harder than it seems.

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Strategic Implications

Why Every 10% Matters

Rating	Monthly (2025)	Annual	20-Year Value
60%	$1,361	$16,332	$326,640
70%	$1,716	$20,592	$411,840
80%	$1,995	$23,940	$478,800
90%	$2,241	$26,892	$537,840
100%	$3,737	$44,844	$896,880

The jump from 90% to 100% is worth $17,952/year. That's significant.

Filing Strategies

1. File bilateral conditions separately If both knees hurt, file for BOTH. The bilateral factor gives you an extra boost.

2. Don't ignore small conditions Even a 10% rating can push you over a rounding threshold. If you're at 64%, adding a 10% condition gets you to 68% → rounds to 70%.

3. Consider TDIU if you can't work If your combined rating is 60%+ (with one condition at 40%+) and you can't work, TDIU pays at the 100% rate.

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Mental Health Conditions: A Special Case

Important: PTSD, depression, anxiety, and other mental health conditions affecting the same symptoms are NOT rated separately. They're combined into one rating under the same criteria.

If you have PTSD (70%) and depression, the VA doesn't add them. They evaluate all your mental health symptoms together and assign one rating that covers everything.

However, distinct conditions with different symptom profiles (like PTSD + TBI with cognitive issues) may be rated separately.

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Verify Your Rating

The VA makes mistakes. Use these steps to check:

1. List all your rated conditions and percentages
2. Use a combined rating calculator (like our VA Combined Rating Calculator)
3. Compare to your rating decision letter
4. If numbers don't match, request a review

Common errors:

• Bilateral factor not applied when it should be
• Conditions combined in wrong order
• Rounding errors
• Missing service-connected conditions

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The 0% Rating Myth

Many veterans skip 0% ratings because "they're worth nothing." But 0% ratings:

• Establish service connection (critical for future increases)
• Can contribute to combined rating in edge cases
• Provide VA healthcare eligibility
• Open doors to secondary condition claims

Never dismiss a 0% rating. It's your foot in the door.

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Use Our Free Calculator

Understanding VA math is important, but calculating it manually is tedious. Use our VA Combined Rating Calculator to:

• Add multiple conditions
• See step-by-step calculations
• Understand bilateral factor impact
• Estimate monthly payments
• Plan future claims

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Key Takeaways

1. VA math isn't simple addition. 50% + 30% = 65%, not 80%
2. The bilateral factor matters. Conditions on both sides of paired body parts get a 10% bonus
3. Rounding rules are critical. Being at 64.5% vs 64.4% is a $355/month difference
4. Every condition counts. Small ratings can push you over thresholds
5. Verify your rating. The VA makes calculation mistakes
6. Mental health combines. PTSD, depression, anxiety = one rating, not three

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Next Steps

1. Review your current rating decision
2. Use our VA Combined Rating Calculator to verify
3. Identify any bilateral conditions that may qualify for the factor
4. Consider filing for secondary conditions to increase your rating
5. Consult a VSO if your calculated rating doesn't match your official rating

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Disclaimer: This information is for educational purposes only. Actual VA ratings depend on medical evidence, C&P exams, and VA adjudicators. This content is not affiliated with or endorsed by the Department of Veterans Affairs.