Bilateral Factor Calculator: VA Disability Math

This calculator works out the combined bilateral factor for VA disability ratings, using the same 10% bilateral factor rule the Department of Veterans Affairs applies. You enter the individual disability ratings for paired body parts (arms, legs, eyes, ears), and the calculator returns the bilateral factor amount and the combined rating including that factor. The result is a percentage you can use to understand how the VA combines bilateral conditions before applying the overall combined rating formula.

Formula

The bilateral factor is calculated as 10% of the sum of the bilateral disability ratings. The formula is:

Bilateral Factor = (Sum of bilateral ratings) × 0.10

Where:

• Sum of bilateral ratings = the total of all individual disability percentages for paired body parts (e.g., left arm 10% + right arm 20% = 30%)
• 0.10 = the fixed 10% bilateral factor

The bilateral factor is then added to the sum of the bilateral ratings to get a combined bilateral value, which is then combined with other non-bilateral ratings using the VA’s whole-person combined rating table.

Worked Example

Using the default inputs: bilateral ratings of 10% and 10%.

1. Sum of bilateral ratings = 10 + 10 = 20%
2. Bilateral factor = 20 × 0.10 = 2%
3. Combined bilateral value = 20 + 2 = 22%

The calculator shows a bilateral factor of 2% and a combined rating with bilateral of 22%. This 22% is then used in the VA combined rating table with any other non-bilateral ratings to get the final combined disability percentage.

Why the Bilateral Factor Exists

The VA created the bilateral factor to account for the extra functional impairment that comes from having disabilities on both sides of the body. For example, losing function in both arms is more disabling than the sum of losing function in each arm separately, because many daily tasks require two working arms. The 10% factor is a policy decision, not a medical formula, and it has been part of VA regulations for decades. It applies to paired extremities (arms, legs, hands, feet) and paired sensory organs (eyes, ears) when both sides have at least a 10% disability.

How to Use the Bilateral Factor in VA Claims

When you have multiple VA disability ratings, the process is:

1. Identify which conditions affect paired body parts (e.g., both knees, both shoulders).
2. Add the bilateral ratings together.
3. Multiply that sum by 0.10 to get the bilateral factor.
4. Add the bilateral factor to the sum of bilateral ratings to get the combined bilateral value.
5. Combine that value with all other (non-bilateral) ratings using the VA combined rating table, which uses the whole-person method (e.g., 50% + 50% = 75%, not 100%).

This calculator only computes the bilateral factor and the combined bilateral value. You still need to use the VA combined rating table for the final combined rating, but the bilateral factor is a necessary step.

Common Mistakes and Misconceptions

• Applying the factor to non-bilateral conditions: The 10% factor only applies to conditions on paired body parts. Do not apply it to a single knee condition or a back condition.
• Rounding too early: The VA rounds the final combined rating to the nearest 10%, but intermediate steps should not be rounded. Keep decimals until the end.
• Confusing bilateral factor with combined rating: The bilateral factor is not the final rating; it is an add-on that gets incorporated into the combined rating table.
• Assuming both sides must be identical: The bilateral factor applies even if the ratings on each side differ (e.g., left arm 10%, right arm 30%). The factor is 10% of the sum, not 10% of each.

Limits of the Bilateral Factor Calculator

This calculator gives you the bilateral factor and the combined bilateral value, but it does not compute the final combined disability rating because that requires the VA’s full combined rating table, which accounts for the diminishing effect of multiple disabilities. Also, the bilateral factor only applies when both sides have at least a 10% rating. If one side is 0%, there is no bilateral factor. The calculator assumes all entered ratings are valid and that the user has correctly identified which conditions are bilateral.

Frequently Asked Questions

What is the bilateral factor in VA disability?

The bilateral factor is a 10% addition to the combined value of disabilities affecting paired body parts (arms, legs, eyes, ears). It is meant to compensate for the extra difficulty of having impairments on both sides. For example, two 10% ratings on the arms become 20% + 2% = 22% before combining with other ratings.

Does the bilateral factor apply to both arms and both legs together?

Yes, the bilateral factor applies to any paired extremities. If you have a left arm and a right leg condition, those are not bilateral because they are not paired. The factor only applies when both sides of the same pair are affected (e.g., both arms, both legs, both eyes, both ears).

How do I combine bilateral and non-bilateral ratings?

First, calculate the bilateral factor and add it to the sum of bilateral ratings to get a combined bilateral value. Then, use the VA combined rating table to combine that value with each non-bilateral rating, starting from the highest. The table uses the whole-person method: a 50% rating leaves 50% efficiency, then a 30% rating reduces the remaining 50% by 30% (15%), giving 65% combined, and so on.

Can the bilateral factor push my rating over 100%?

No, the maximum combined rating is 100%. The bilateral factor is just an intermediate step; the final combined rating is capped at 100%. Even if the math would produce a number above 100%, the VA pays at 100%.

What if one side is 0% but the other is 30%?

There is no bilateral factor because both sides must have a compensable rating (at least 10%) for the factor to apply. A single 30% rating is combined with other ratings normally, without the bilateral factor.

Is the bilateral factor the same as the combined rating table?

No. The bilateral factor is a separate add-on specifically for paired body parts. The combined rating table is the general method for combining all disabilities, including the bilateral value. You need both steps to get the final rating.

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in bilateral | Bilateral ratings (e.g., 10, 20, 30) | % | 10, 10 | 0
out bilateral_factor | Bilateral factor | % | (10 + 10) * 0.10 | 2
out combined_with_bilateral | Combined rating with bilateral | % | 10 + 10 + ((10 + 10) * 0.10) | 2