VA Combined Rating Calculator: How VA Math Actually Works (2026)

Why VA Math Doesn't Add Up (Literally)

One of the most common sources of confusion for veterans navigating the disability system is why their combined rating doesn't match the sum of their individual ratings. A veteran rated at 50% for PTSD and 30% for sleep apnea reasonably expects a combined rating of 80% — but the VA calculates a combined rating of 65%, which rounds to 70%. Why?

The answer lies in the VA's "whole person" or "combined ratings" methodology, codified in 38 CFR Part 4. The VA's approach is based on the medical concept that you cannot be more than 100% disabled. Instead of adding percentages linearly, the VA applies each disability to the portion of the veteran that remains non-disabled after accounting for prior disabilities.

The Whole Person Formula Explained

Here is the mathematical principle behind VA combined ratings:

1. Start with 100% (representing a fully non-disabled person).
2. Apply the highest-rated disability first. This reduces the "remaining efficiency" of the veteran.
3. Apply the next highest disability to the remaining efficient portion — not to 100%.
4. Continue until all disabilities have been applied.
5. Subtract the final combined disability from 100% to get the combined rating.
6. Round the final combined rating to the nearest 10%.

Step-by-Step Example with Real Numbers

Let's walk through a veteran with three service-connected conditions:

• PTSD: 70%
• Sleep Apnea (secondary to PTSD): 50%
• Lumbar Disc Disease: 20%

Step 1: Apply the highest rating (70% PTSD) to 100%.
Remaining efficiency = 100% − 70% = 30%

Step 2: Apply the next rating (50% sleep apnea) to the remaining 30%.
Disability from sleep apnea = 50% × 30% = 15%
Remaining efficiency = 30% − 15% = 15%

Step 3: Apply the third rating (20% lumbar) to the remaining 15%.
Disability from lumbar = 20% × 15% = 3%
Remaining efficiency = 15% − 3% = 12%

Step 4: Calculate combined disability.
Combined disability = 100% − 12% = 88%

Step 5: Round to nearest 10%.
88% rounds to 90% (since 8 ≥ 5, round up).

This veteran's combined rating would be 90% — not 140% (the sum of individual ratings).

The Bilateral Factor

The bilateral factor is an additional adjustment that applies when a veteran has compensable (10% or higher) disability ratings affecting both paired extremities — both arms, both legs, or one arm and one leg on opposite sides. The bilateral factor adds 10% to the combined rating for those bilateral conditions before they are combined with other disabilities.

Example of Bilateral Factor Application

Suppose a veteran has:

• Right knee: 20%
• Left knee: 10%
• Tinnitus: 10%

Step 1: Calculate the bilateral combined rating for both knees.
Apply 20% to 100%: Remaining = 80%
Apply 10% to 80%: 10% × 80% = 8% additional disability
Combined for knees: 20% + 8% = 28%

Step 2: Apply the bilateral factor (10% of 28%).
Bilateral adjustment = 10% × 28% = 2.8%
Adjusted knee combined = 28% + 2.8% = 30.8%, rounded to 31%

Step 3: Combine 31% (bilateral knees) with tinnitus 10%.
Apply 31% to 100%: Remaining = 69%
Apply 10% to 69%: 10% × 69% = 6.9%
Combined = 31% + 6.9% = 37.9%

Step 4: Round 37.9% to nearest 10% = 40% combined rating.

Rounding Rules for Final Combined Ratings

The VA applies a specific rounding rule after all disabilities are combined:

• Final percentage ending in 0–4: Round down to the nearest 10%
• Final percentage ending in 5–9: Round up to the nearest 10%

This means the difference between a 64% and a 65% combined rating is a full 10% rating — jumping from 60% to 70%. For veterans near a rounding threshold, adding even a modestly-rated secondary condition can push the combined rating to the next bracket, which can meaningfully affect monthly compensation.

2026 VA Disability Compensation Rates

VA compensation rates are adjusted annually based on the Cost of Living Adjustment (COLA). The 2026 rates reflect the most recent COLA increase. Below are approximate monthly rates for veterans with no dependents:

• 10% — $175.51/month
• 20% — $346.95/month
• 30% — $537.42/month
• 40% — $773.16/month
• 50% — $1,102.04/month
• 60% — $1,395.83/month
• 70% — $1,759.69/month
• 80% — $2,044.89/month
• 90% — $2,297.96/month
• 100% — $3,737.85/month

Veterans with dependents — spouses, children, dependent parents — receive additional compensation at each rating level. The increase from 90% to 100% (approximately $1,440/month) is the largest single jump in the VA compensation schedule and is why many veterans focus on moving from a high combined rating to 100%.

Using the Semper Solutus VA Disability Calculator

Rather than calculating combined ratings manually, you can use the Semper Solutus VA Disability Calculator, which applies the exact VA combined rating formula, includes the bilateral factor adjustment, handles rounding correctly, and shows your estimated 2026 monthly compensation with dependent adjustments.

The calculator covers 37 service-connected conditions with condition-specific rating percentages, allowing you to model different claim scenarios and understand how adding secondary conditions affects your combined rating and monthly compensation estimate. It uses real VA math — not simple addition — so the results accurately reflect how the VA would calculate your combined rating.