VA Math Calculator 2026 — Combined Rating, SMC, TDIU
Free combined-rating calculator using 38 CFR §4.25 + §4.26 bilateral, with automatic SMC and TDIU flags. 2026 VA rates (effective Dec 1, 2025 · 2.8% COLA · 100% = $3,938.58/mo). 100% private — no email, no signup.
Updated June 2026 · Source: va.gov compensation rates
Common condition presets (tap to add)
Dependents (only count at 30%+)
SMC qualifying conditions (each adds ~$140/mo)
Combined VA Disability Rating
0%
Pre-round: 0.0%
✅ Federal income tax-free per 38 USC §5301.
Breakdown
🦵 Bilateral Factor (38 CFR §4.26) applied
⚠ Special Monthly Compensation
🪖 TDIU (Individual Unemployability) — §4.16
📐 Show the math (38 CFR §4.25 + §4.26)
How VA Math actually works
The VA does not add your ratings. It uses the combined ratings table in 38 CFR §4.25, which treats each disability as a portion of your remaining healthy capacity. Your highest rating is applied first, leaving the rest of your "efficiency" unaffected. The next rating is applied to that remaining efficiency. The chain continues for every disability, then the final number is rounded to the nearest 10%.
Example: Two 50% disabilities don't make 100%. The first 50% leaves 50% healthy. The next 50% of that 50% takes another 25% → combined 75% → rounded to 80%. Three 30% disabilities don't make 90%. They combine to about 65.7% → rounded to 70%. This is why veterans are constantly surprised at their letters.
Bilateral factor — the most-missed bump
Under 38 CFR §4.26, conditions affecting both arms or both legs (or paired skeletal muscles) get a 10% bonus on top of their combined sub-total, BEFORE being folded into the rest of your ratings. Most calculators apply this wrong, or skip it entirely. Ours implements §4.26 the way the regulation reads — and per §4.26(d) picks whichever path (with or without the bonus) gives you the higher final rating.
SMC and TDIU — money many veterans miss
SMC-K adds $139.87/month for each loss of a creative organ, hand, foot, eye, ear, breast, or speech function — and SMC-K conditions stack. SMC-S pays $4,408.53/month for housebound veterans. TDIU (Individual Unemployability) pays at the 100% rate even without a 100% schedular rating if you have 60% from a single disability OR 70% combined with one at 40%, AND you cannot maintain substantially gainful employment. Calculator flags both automatically based on your inputs.
Deeper guides: how VA Math actually works · bilateral factor 2026 · SMC eligibility · TDIU 2026 · back-pay calculation · 2026 COLA update.
VA Math FAQ
Why is my combined rating not just the sum of my ratings?
VA uses 38 CFR §4.25 "whole-person" math: each disability reduces remaining healthy capacity, not original capacity. Two 50% ratings combine to 75%, not 100%. The calculator above runs the exact CFR formula and rounds to the nearest 10% only at the end.
What is the bilateral factor and when does it apply?
38 CFR §4.26: when you have service-connected disabilities of BOTH arms or BOTH legs, those paired ratings are combined first, then VA adds 10% of that combined value as a bonus, then folds it into the rest. Many calculators apply this wrong — ours applies §4.26 correctly and shows the bonus dollars.
Is VA disability compensation taxable?
No. VA disability compensation is fully tax-free at the federal level per 38 U.S.C. §5301. It is not reportable on your 1040. Most states also exempt it.
What is TDIU and do I qualify?
Total Disability Individual Unemployability (38 CFR §4.16) pays at the 100% rate without a 100% schedular rating. You may qualify with 60% from a single disability, OR 70% combined with at least one disability at 40%. You must also be unable to maintain substantially gainful employment. File VA Form 21-8940.
How is this calculator different from law-firm tools?
No email gate, no phone capture, no upsell. The calculation runs entirely in your browser — open DevTools → Network tab to verify nothing leaves your device. We also apply §4.26 bilateral correctly, flag SMC eligibility automatically, show the full math, and use the verified 2026 rates effective Dec 1, 2025 (2.8% COLA).
What is SMC?
Special Monthly Compensation under 38 CFR §3.350 pays EXTRA on top of regular comp for specific situations: loss of organs/limbs (SMC-K, $139.87/mo each — stacks), housebound (SMC-S, $4,408.53/mo), aid & attendance (SMC-L through R2). The calculator flags likely eligibility based on your inputs.