Key Takeaways
- The “Boost”: The bilateral factor adds 10% to the combined rating of paired disabilities (arms, legs, or paired muscles) before they are combined with other ratings.
- Eligibility: It applies to paired extremities (e.g., left leg and right leg), even if the conditions are different (e.g., left knee and right ankle).
- Exclusions: It generally does not apply to eyes or ears, which use different rating scales.
- Automatic Calculation: Modern tools handle this complex math for you. Use our guide on How to Use the VA Disability Calculator to see your true rating.
The VA Bilateral Factor is a specific calculation rule used by the Department of Veterans Affairs to increase the disability rating for veterans who have service-connected disabilities affecting both sides of their body (such as both arms, both legs, or paired skeletal muscles). The VA recognizes that bilateral disabilities limit a veteran’s ability to function more severely than unilateral ones, so they add 10% to the combined value of these disabilities.
How the Bilateral Factor Works
If you are new to VA claims, you likely know that “VA Math” is rarely simple addition. When you have multiple disabilities, the VA uses a “Combined Ratings Table” to determine your final percentage. This usually results in a number lower than the simple sum of your ratings.
However, the **Bilateral Factor** is one of the few instances where VA math works in your favor.
According to 38 CFR § 4.26, if you have a partial disability resulting from disease or injury of **both arms**, **both legs**, or **paired skeletal muscles**, the VA must apply this factor.
### The Calculation Steps:
1. **Isolate Bilateral Conditions:** The VA separates your bilateral conditions from your other disabilities.
2. **Combine Them:** They calculate the combined rating of just these bilateral conditions using the standard efficiency table.
3. **The 10% Boost:** They take 10% of that combined value and **add** it to the combined value.
4. **Final Combination:** This boosted number is then combined with your remaining non-bilateral disabilities to get your final score.
Does My Condition Qualify?
Not every “paired” organ qualifies for the 10% bilateral math boost. The rule is specific to extremities and skeletal muscles.
* **Qualifying Examples:**
* **Lower Extremities:** Service-connected left knee pain and right ankle limitation.
* **Upper Extremities:** Right shoulder strain and left wrist carpal tunnel.
* **Muscle Groups:** Injury to paired muscle groups on both sides of the torso.
* **Non-Qualifying Examples:**
* **Eyes & Ears:** While these are paired organs, they are rated under different schedules (38 CFR 4.79 and 4.85) that have their own method for handling bilateral impairment.
* **Unmatched Limbs:** A left arm condition and a right leg condition do **not** trigger the bilateral factor because they are not a matching pair of extremities (both upper or both lower).
For a deeper dive into how limb conditions are rated, read our guide on Musculoskeletal Conditions and VA Disability.
The Math in Action: Why It Matters
The bilateral factor can be the difference between a 90% rating and a 100% rating. Because the VA rounds to the nearest 10%, a few extra percentage points from the bilateral factor can push you over a rounding threshold.
### Comparison: Standard Math vs. Bilateral Factor
Let’s look at a veteran with a **30% rating for the Left Leg** and a **30% rating for the Right Leg**.
| Step | Standard Math (No Bilateral) | Bilateral Factor Math |
|---|---|---|
| 1. Combine Ratings | 30% combined with 30% = 51% | 30% combined with 30% = 51% |
| 2. Apply Boost | None | 10% of 51 is 5.1. Add 5.1 to 51 = 56.1% |
| 3. Rounding | 51% rounds down to 50% | 56.1% rounds up to 60% |
| Final Rating | 50% | 60% |
As you can see, without the bilateral factor, the veteran is stuck at 50%. With the factor, they jump to 60%, which significantly increases monthly compensation.
For more on how ratings are combined, check out Understanding Combined Ratings: Why 50% + 50% Doesn’t Equal 100%.
Common Misconceptions
### 1. “It applies to any two disabilities.”
False. It only applies to **paired extremities** (both arms or both legs) or paired skeletal muscles. A right arm and left leg do not qualify.
### 2. “The conditions must be the same.”
False. You do not need “bilateral knee pain.” You can have a left knee condition and a right foot condition. As long as both lower extremities are affected, the factor applies.
### 3. “It always increases my rating.”
Technically, the math is designed to increase the rating, but due to rounding, it might not always result in a higher *final* percentage (e.g., if you jump from 87% to 89%, you are still rounded to 90%). However, it never hurts your rating.
Frequently Asked Questions (FAQ)
Does the bilateral factor apply to Tinnitus or Hearing Loss?
Generally, no. Hearing loss and tinnitus are rated under special tables. While hearing loss is inherently bilateral, it does not receive the specific “10% combined value boost” described in 38 CFR 4.26.
Can I calculate this myself?
You can, but it is tedious and prone to error. We strongly recommend using a verified calculator. If you are trying to maximize your rating, review our article on Strategies for Veterans with Multiple Disabilities.
What happens if I have disabilities in both arms AND both legs?
The VA will combine all bilateral upper extremity ratings and all bilateral lower extremity ratings together, apply the bilateral factor to that massive group, and then combine that result with any other disabilities (like PTSD or IBS).
Next Steps
If you suspect your rating was calculated incorrectly, or if you have a new condition affecting a “good” limb that might now trigger the bilateral factor, it is time to review your file.
* **Check your math:** How to Use the VA Disability Calculator
* **Understand the basics:** VA Disability Ratings 101
Ensuring the VA applies the bilateral factor correctly is a critical step in receiving the full compensation you earned.