What Is the VA Bilateral Factor?
The bilateral factor is a 10% bonus added to your combined rating when you have service-connected disabilities affecting both sides of your body — both legs, both arms, or paired muscle groups like both shoulders or both knees.
The legal basis is 38 CFR 4.68, which states:
"The ratings for the disabilities of an extremity shall be combined, 10 percent of that combined value added (bilateral factor), and the sum shall then be combined with the ratings of other disabilities."
In plain English: if you hurt both knees in service, the VA doesn't just add your knee ratings to your other ratings. It first combines both knee ratings together, adds 10% of that number, and then combines that adjusted figure with everything else.
The purpose is simple — having disabilities on both sides of your body is more disabling than the same conditions on one side. It affects your gait, your balance, your ability to compensate. The bilateral factor acknowledges that.
Which Conditions Qualify for the Bilateral Factor?
The bilateral factor applies when you have paired disabilities — meaning the same type of disability on both the left and right side of your body.
Common bilateral conditions that qualify:
| Condition | Example |
|---|---|
| Both knees | Left knee 10% + Right knee 10% |
| Both hips | Left hip 20% + Right hip 10% |
| Both ankles | Left ankle 10% + Right ankle 10% |
| Both shoulders | Left shoulder 20% + Right shoulder 10% |
| Both elbows | Left elbow 10% + Right elbow 10% |
| Both wrists | Left wrist 10% + Right wrist 10% |
| Both feet | Left foot 10% + Right foot 10% |
| Bilateral hearing loss | Left ear + Right ear combined |
| Both hands | Left hand 10% + Right hand 10% |
The rule is: the disabilities must affect both extremities — both arms, both legs, or paired muscle groups used in locomotion.
What does NOT qualify:
- A single knee disability (only one side)
- Back and knee (not a paired extremity)
- PTSD and a knee condition (mental health + physical is not bilateral)
- Two conditions on the same side (both a shoulder and elbow on the right side)
How the VA Calculates the Bilateral Factor — Step by Step
The bilateral factor is calculated before your bilateral disabilities are combined with your other ratings. This is the part that confuses most veterans.
The formula has three stages:
Stage 1 — Combine the bilateral disabilities together first
Use the standard VA combined rating formula on your bilateral conditions only.
Example:
- Right knee: 10%
- Left knee: 10%
Step 1: Apply the higher rating to the whole person.
100% × 10% = 10 points of disability → 90% remaining
Step 2: Apply the second rating to the remaining whole person.
90% × 10% = 9 points of disability
Step 3: Add them.
10 + 9 = 19% combined bilateral disability
Stage 2 — Add 10% of that combined bilateral value (the bilateral factor)
Take your combined bilateral result and add 10% of it.
19% × 10% = 1.9
Round this to the nearest whole number: 1.9 rounds to 2
19 + 2 = 21% adjusted bilateral value
Stage 3 — Now combine the adjusted bilateral value with all other disabilities
Take that adjusted 21% and combine it with your remaining service-connected conditions using the standard whole person formula.
Full example with all conditions:
| Condition | Rating |
|---|---|
| PTSD | 70% |
| Right knee | 10% |
| Left knee | 10% |
| Tinnitus | 10% |
Step 1 — Combine bilateral conditions (knees only):
- Right knee 10% + Left knee 10% combined = 19%
- Add bilateral factor: 19 × 10% = 1.9 → rounds to 2
- Adjusted bilateral value = 21%
Step 2 — Combine all disabilities using whole person method:
Sort by highest first:
- PTSD 70% → 100 × 70% = 70 points → 30% remaining
- Bilateral knees (adjusted 21%) → 30 × 21% = 6.3 points → 23.7% remaining
- Tinnitus 10% → 23.7 × 10% = 2.37 points
Add all points: 70 + 6.3 + 2.37 = 78.67%
Apply rounding rules → 78.67% rounds to 79% → rounds to final rating of 80%
Without the bilateral factor, those two 10% knees would have contributed less to the combined total. The bilateral factor added roughly 1–2 percentage points — which can be the difference between 70% and 80% for veterans already close to a threshold.
Use the VA Combined Rating Calculator to run your own numbers with bilateral factor automatically applied.
Why the Bilateral Factor Matters More Than You Think
A 1–2 point boost sounds small. But look at the 2026 VA pay rates:
| Rating | Monthly Pay (Single Veteran) |
|---|---|
| 60% | $1,395.93 |
| 70% | $1,759.19 |
| 80% | $2,044.89 |
| 90% | $2,297.96 |
| 100% | $3,831.30 |
The difference between 70% and 80% is $285.70 per month — $3,428 per year.
If the bilateral factor pushes your combined rating from 79% to 80%, that's real money. And if it pushes you past the 94% threshold to 95%, you round up to 100% — a difference of over $1,500/month.
See the full 2026 VA disability pay rates by rating.
Does the VA Automatically Apply the Bilateral Factor?
It should — but mistakes happen.
The VA is supposed to identify bilateral conditions during the rating process and apply the factor automatically. In practice, veterans are sometimes rated without it being applied, especially when:
- Bilateral conditions are claimed at different times (right knee in 2019, left knee in 2022)
- The rater doesn't flag both conditions as bilateral
- Secondary conditions (like a second knee injury caused by favoring the first) aren't connected
What you should do:
- Review your Rating Decision letter carefully
- Look for the phrase "bilateral factor" — it should appear in the math breakdown if it was applied
- If it's missing and you have paired conditions, file for a rating review or supplemental claim
Secondary Conditions and the Bilateral Factor
Here's a situation many veterans miss: secondary conditions can qualify for the bilateral factor too.
Example: You have a service-connected right knee disability. You develop a left knee problem because you've been favoring your right side for years. If the VA service-connects that left knee as secondary to the right knee, both knees now qualify for the bilateral factor — even though only one was directly service-connected.
This is one of the most overlooked rating increases available. See how to claim secondary VA disabilities for a full walkthrough.
Bilateral Factor vs. Combined Rating — Key Difference
| Bilateral Factor | Standard Combined Rating | |
|---|---|---|
| When it applies | Only paired extremity disabilities | All service-connected conditions |
| What it does | Adds 10% to the bilateral sub-total | Applies whole person math to everything |
| Legal basis | 38 CFR 4.68 | 38 CFR 4.25 |
| Applied by VA automatically? | Should be — verify your decision letter | Yes |
The bilateral factor is not a separate rating. It's an adjustment applied during the VA combined rating calculation before your final number is determined.
Frequently Asked Questions
Does the bilateral factor apply to hearing loss? +
Yes. Bilateral hearing loss — hearing disability in both ears — qualifies for the bilateral factor. The VA rates each ear separately and the bilateral factor applies to the combined ear ratings.
What if I only have one knee rated — does bilateral factor apply? +
No. You need service-connected disabilities on both sides for the bilateral factor to apply. One knee alone does not qualify.
Can I claim the bilateral factor after my rating is already decided? +
Yes. If your rating decision did not apply the bilateral factor and it should have, you can file a supplemental claim or request a higher-level review. There is no time limit on correcting this.
Does the bilateral factor affect TDIU? +
Not directly. TDIU (Total Disability Individual Unemployability) is based on whether your disabilities prevent you from working, not on specific arithmetic. However, a higher combined rating from the bilateral factor can make you more easily eligible for TDIU if your conditions warrant it.
Can mental health conditions trigger the bilateral factor? +
No. Mental health conditions like PTSD, depression, or anxiety do not qualify for the bilateral factor. It is limited to physical disabilities of paired extremities and muscle groups used in locomotion.
Key Takeaways
- The bilateral factor adds 10% of your combined bilateral rating to your overall calculation
- It applies to both arms, both legs, or paired muscle groups — not mental health or single-sided conditions
- The VA should apply it automatically, but verify your rating decision letter
- Secondary conditions on the opposite side can also qualify
- Even a small bilateral factor boost can push your combined rating past a pay threshold
Check your exact combined rating with bilateral factor applied automatically:
→ Use the Free VA Combined Rating CalculatorRelated Articles
This article is for informational purposes only. Not affiliated with the U.S. Department of Veterans Affairs. All calculations are based on the official 38 CFR 4.68 bilateral factor formula and 38 CFR 4.25 combined ratings formula. For decisions about your specific claim, consult an accredited VA claims agent or veterans service organization (VSO).