Imputed Income Calculator — Group-Term Life Insurance

What is imputed income?

Imputed income is the taxable value of a benefit you receive in a form other than cash. You never see the money, but the IRS treats the benefit as if your employer had paid you its value in wages — so it shows up on your W-2 and gets taxed. The classic example, and the one this calculator handles, is employer-provided group-term life (GTL) insurance: the first $50,000 of coverage is tax-free, but the cost of anything above that is "imputed" to you as income even though your employer paid the premium.

If your pay stub shows a line like "GTL", "Group Term Life", or "Imputed income", this is what it is — an accounting entry that raises your taxable wages without raising your take-home pay. Your net pay drops only by the FICA tax withheld on the imputed amount.

The §79 rule: $50,000 tax-free, Table I above it

Under IRC §79(a), the first $50,000 of employer-provided group-term life coverage is excluded from your gross income. The $50,000 threshold was set in 1964 and has never been adjusted for inflation — which is why a benefit of one or two times salary now pushes many ordinary earners over the line.

For coverage above $50,000, the taxable cost is NOT what your employer actually pays the insurer. Instead, the IRS prescribes uniform monthly premium rates — "Table I" in Publication 15-B (26 CFR §1.79-3(d)(2)) — per $1,000 of excess coverage, banded by your attained age on the last day of the tax year. The excess coverage is figured to the nearest $100, the monthly cost is multiplied by the months of coverage, and any premium you paid with after-tax dollars is subtracted.

IRS Table I: monthly cost per $1,000 of excess coverage

These rates are statutory-static — unchanged since July 1, 1999 — and apply to every employer's plan regardless of what the insurance actually costs. Use your age on December 31 of the tax year.

Note the steep age gradient: the same $100,000 of excess coverage costs a 40-year-old $120 of imputed income per year but a 70-year-old $2,472. Table I is also the reason "free" supplemental life through work can be worse than a private policy for older, healthy employees — the imputed income can exceed what a term policy would cost outright.

Worked example (from IRS Pub 15-B)

A 51-year-old employee has $150,000 of employer-paid group-term life coverage for the full year and contributes nothing toward it:

The $276 appears in W-2 Boxes 1, 3, and 5 and in Box 12 with code C. The employee's actual out-of-pocket cost during the year is only the $21.11 of FICA — the income tax on the $276 is settled on the Form 1040.

That 7.65% is not universal — it only holds because this employee's imputed income is far below both the Social Security wage base and the Additional Medicare threshold. A higher earner with $500,000 of coverage, other wages of $250,000, and the same age pays an effective 2.35% on the imputed income instead: the 6.2% Social Security share drops out once other wages already exceed the wage base, while the Medicare share rises to 2.35% once total wages pass the $200,000 single-filer Additional Medicare threshold. Enter your own wages, filing status, and tax year above for your actual rate.

W-2 Box 12 code C: where the number lands

Your employer reports the taxable GTL cost in four places on the W-2, but it is only taxed once:

• Box 1 — federal wages. The imputed income is included, so it is taxed as ordinary income when you file. No income-tax withholding was required on it during the year, which can slightly reduce your refund.
• Box 3 — Social Security wages. Included (up to the annual wage base); 6.2% was withheld.
• Box 5 — Medicare wages. Included with no cap; 1.45% was withheld.
• Box 12, code C. The same amount shown separately for information. You do not enter it anywhere on your return — it is already in Box 1.

Former employees may instead see codes M and N — uncollected Social Security and Medicare tax on GTL coverage that continued after leaving — which DO create a liability on Schedule 2. See the W-2 box guide for every box and code.

Other common types of imputed income

• Personal use of a company car. Valued under the annual lease value, cents-per-mile, or commuting rules in Pub 15-B and added to wages.
• GTL coverage on a spouse or dependent over $2,000. Loses the de minimis exception entirely — the full Table I cost is imputed, not just the excess over $2,000.
• Domestic partner health coverage. Employer-paid coverage for a partner who is not your tax dependent is imputed income at fair market value — one of the largest imputed amounts in practice.
• Employer-paid education over $5,250. Amounts above the §127 exclusion are wages unless they qualify as a working-condition fringe.

Sources

• IRS Publication 15-B — Employer's Tax Guide to Fringe Benefits
• 26 CFR § 1.79-3 — Group-Term Life Insurance (Table I Uniform Premiums)