VA Bilateral Factor Evidence Checklist: How to Check Paired Arm and Leg Ratings

The VA bilateral factor is one of the easiest parts of VA math to overlook because it is not a separate disability rating. It is a calculation step VA uses when compensable service-connected disabilities affect paired extremities: both arms, both legs, or paired skeletal muscles.

This guide is for veterans reviewing a rating decision, planning a rating increase, checking a calculator result, or deciding whether the opposite arm or leg needs stronger evidence. TYFYS is a private paid service. We are not the VA, not a VSO, and not a law firm. This is educational evidence strategy, not legal or medical advice.

Table of Contents

• What the VA bilateral factor is
• When the bilateral factor applies
• How to calculate it in 5 steps
• The evidence checklist
• Common qualifying examples
• When it usually does not apply
• How to check your rating decision
• How TYFYS fits into the process
• FAQ

What the VA bilateral factor is

The bilateral factor is not a bonus rating that appears as its own condition. It is a calculation rule in 38 CFR 4.26. When the criteria are met, VA first combines the ratings for the paired right-side and left-side disabilities. VA then adds 10% of that combined value to the paired-disability value before combining it with other ratings.

The regulation says the factor applies before the other combinations are carried out. That sequence matters. If VA combines all ratings first and thinks about laterality last, the final number can be wrong.

VA's public disability-ratings page also explains the larger VA math principle: multiple ratings are not added normally. VA uses the combined ratings table and rounds the final combined value to the nearest 10%. That is why the bilateral factor can matter even when it only adds a few raw percentage points.

A 2.8-point bilateral adjustment may not sound large, but it can be the difference between rounding down and rounding up.

When the bilateral factor applies

Use this screening test. A likely bilateral-factor issue exists when all 4 points are true:

1. There are at least 2 affected sides: right and left arms, right and left legs, or paired skeletal muscles.
2. Both sides are service connected: VA has awarded a rating for each qualifying side.
3. Both sides are compensable: each side is generally rated at 10% or higher, not just listed at 0%.
4. The disabilities affect paired use: examples include knees, ankles, feet, hips, shoulders, elbows, wrists, hands, radiculopathy, peripheral neuropathy, or paired skeletal muscle injuries.

The disabilities do not have to be mirror-image diagnoses. A right knee strain and left ankle instability can still affect the lower extremities. A right lower extremity radiculopathy rating and a left peripheral neuropathy rating may also raise a bilateral-factor question if both are compensable and service connected.

How to calculate it in 5 steps

Here is the practical version of the calculation. Use it to sanity-check the result, not to replace VA's final decision.

1. List only qualifying paired ratings first. Example: right knee 20%, left ankle 10%.
2. Combine those paired ratings using VA math. A 20% rating combined with a 10% rating equals 28%, not 30%.
3. Find 10% of that paired value. Ten percent of 28 is 2.8.
4. Add the factor to the paired value. 28 plus 2.8 equals 30.8.
5. Continue combining with the rest of the ratings. Treat the adjusted paired value as one rating in the remaining combined-rating calculation.

In a real file, the math may involve 3 or 4 extremities, several nerve ratings, or other non-bilateral ratings. That is why the first step is not "guess the final percentage." The first step is to identify which ratings qualify for the paired-extremity group.

The evidence checklist

If the bilateral factor looks wrong, the evidence problem is usually one of 3 things: one side is missing, one side is noncompensable, or the file does not clearly show why both sides should be service connected. Use this checklist before deciding what to do next.

1. Current rating list

Download or save your current individual ratings and combined rating. Note the exact condition names, percentages, effective dates, and whether VA separated the right and left side. Start with the TYFYS guide to viewing and saving your VA rating if you do not have a clean copy.

2. Laterality proof

Make sure the medical records identify the side: right, left, bilateral, upper extremity, lower extremity, dominant arm, non-dominant arm, or affected nerve. A record that says "leg pain" may be less useful than one that says "right lower extremity radiculopathy with numbness into the foot."

3. Compensable severity facts

The bilateral factor generally requires a compensable disability on each side. That means the file must support symptoms, measurements, or functional limits that justify a rating on each side. For joints, that may include range of motion, painful motion, instability, flare-ups, bracing, or assistive devices. For nerves, it may include sensory loss, weakness, reflex changes, pain, numbness, tingling, or functional impairment.

4. Separate service connection for each side

If only one side is service connected, the bilateral factor usually does not apply yet. The next evidence question may be whether the other side has its own direct service connection, secondary service connection, or aggravation theory. For example, a service-connected right knee may contribute to a left knee or ankle issue through altered gait, but that usually needs medical explanation.

5. DBQ or exam alignment

Review the DBQ or C&P exam findings for each affected side. The exam should not accidentally discuss one side in detail and ignore the other. If a records-only review is pending, use the VA ACE exam evidence checklist to organize what the reviewer needs to see.

6. Lay evidence for paired functional loss

Lay evidence can document how two impaired limbs function together: falls, needing handrails, dropping objects, trouble standing from a chair, needing a cane, reduced grip, avoiding stairs, or stopping after a short walk. Use the VA buddy statement guide and VA personal statement guide to keep statements specific.

7. Calculator comparison

Run the ratings once with the paired-extremity issue included and once without it. If the final rounded rating changes, the issue may have a real monthly-compensation impact. If the final rounded rating does not change today, it may still matter after a future increase or new secondary rating.

Common qualifying examples

The table below shows common situations where veterans should check whether the bilateral factor was applied. It is not a guarantee that any specific claim qualifies.

Pattern	Why it matters	Related TYFYS guide
Right knee and left knee ratings	Both knees affect the lower extremities. Instability, painful motion, limitation of flexion, or separate knee findings may change the math.	VA knee instability checklist
Right leg radiculopathy and left leg radiculopathy	Separate lower-extremity nerve ratings often create a bilateral-factor question, especially when spine claims include symptoms down both legs.	Radiculopathy rating guide
Peripheral neuropathy in both feet or hands	Diabetes, toxic exposure, or nerve injuries can involve multiple extremities, and each rated limb may affect combined VA math.	Peripheral neuropathy checklist
Foot, ankle, hip, or shoulder ratings on opposite sides	The regulation looks at paired extremities as a whole, not only identical diagnoses. A right foot and left hip issue may still deserve review.	Plantar fasciitis checklist
Both arms, wrists, hands, or shoulders	Upper-extremity ratings can trigger the factor when both sides are compensable and service connected.	VA carpal tunnel rating checklist or VA shoulder rating checklist

When it usually does not apply

The bilateral factor is often misunderstood. These situations commonly do not trigger it:

• Only one side is service connected. Pain in the other limb does not count until VA awards service connection for that side.
• One side is rated 0%. A noncompensable rating usually does not meet the compensable-degree requirement in 38 CFR 4.26.
• The conditions are not paired extremities or paired skeletal muscles. PTSD, GERD, IBS, tinnitus, asthma, and hypertension are not arm-or-leg paired extremity ratings.
• The same symptom is being counted twice. VA rules generally avoid pyramiding, so a veteran should not assume every bilateral-sounding condition produces a second adjustment. Use the VA pyramiding rule evidence checklist if the issue is separate symptoms rather than paired-extremity math.
• A single rating already covers a bilateral condition. Some ratings are written as one bilateral condition; review the decision letter before assuming the factor was missed.

There are edge cases, including the 2023 exception in 38 CFR 4.26(d), where VA should remove certain bilateral disabilities from the bilateral calculation if doing so produces the most favorable combined evaluation. If your file is complex, consider reviewing the decision with an accredited representative or another qualified professional.

How to check your rating decision

VA rating decisions do not always make the bilateral factor easy to see. Look for these clues:

1. A combined rating worksheet: some files show a bilateral-factor line or adjusted paired value.
2. Language citing 38 CFR 4.26: the decision may mention the bilateral factor directly.
3. Separate right and left ratings: condition names may identify "right lower extremity" and "left lower extremity."
4. Unexpected VA math: the combined rating may be slightly higher than a straight table calculation without the bilateral factor.
5. Missing opposite-side evidence: if one side is not listed at all, the problem may be service connection or evidence, not the calculator.

If the issue is a potential VA calculation error, the next procedural step is different from a medical-evidence gap. If the issue is that the second side is not service connected or is underrated, the evidence path may involve a supplemental claim, increase claim, or secondary service-connection theory. Review the supplemental claim evidence checklist before uploading new evidence to the wrong lane.

How TYFYS fits into the process

TYFYS helps veterans organize private medical evidence and claim-readiness strategy. For a bilateral-factor review, that usually means mapping current ratings, decision letters, DBQs, VA and private records, symptom history, laterality, and functional loss to the claim path the veteran is considering.

Start with VA math explained and the VA rating calculator. If one side is missing or the severity facts are weak, review private medical evidence and the condition-specific checklist that matches the affected limb.

FAQ

What is the VA bilateral factor?

The VA bilateral factor is a combined-rating calculation rule for compensable service-connected disabilities affecting both arms, both legs, or paired skeletal muscles. VA combines the qualifying paired ratings, adds 10% of that value, and then continues the remaining VA math.

Does the bilateral factor mean I get another 10% rating?

No. It is not a separate 10% disability rating. It is 10% of the combined value of the qualifying paired disabilities, added before the rest of the combined-rating calculation continues.

Can a right knee and left ankle qualify?

Potentially, yes. The disabilities do not have to be identical. The key question is whether both are compensable, service-connected disabilities affecting paired lower extremities. The final decision belongs to VA.

Does a 0% rating count for the bilateral factor?

Usually no. 38 CFR 4.26 says the bilateral factor is not applicable unless there is partial disability of compensable degree in each of 2 paired extremities or paired skeletal muscles.

What should I do if my bilateral factor looks wrong?

First, save the rating decision and list each individual rating by side. Then compare the math, identify whether the problem is calculation, missing service connection, or weak severity evidence, and decide whether an accredited representative or evidence review is needed.

Sources and official references

• 38 CFR 4.26, bilateral factor
• VA about disability ratings and combined ratings
• VA upload evidence guidance
• VA Form 21-4138 and related statement forms