Marginal Tax Rate Calculator

What Is Marginal Tax Rate?

Your marginal tax rate is the tax rate applied to your last (highest) dollar of taxable income. In the US progressive tax system, income is divided into brackets, each taxed at a progressively higher rate. Only the income within each bracket is taxed at that bracket's rate — not your entire income. For example, if you are a single filer earning $100,000 in 2026, your marginal rate is 22%, but only the income between $48,475 and $100,000 is taxed at 22%. The lower portions are taxed at 10% and 12%. This is why "moving into a higher bracket" does not mean all your income is taxed at the higher rate. Source: IRS Revenue Procedure 2025-19.

2026 Marginal Tax Brackets by Filing Status

The IRS maintains seven federal income tax rates: 10%, 12%, 22%, 24%, 32%, 35%, and 37%. For single filers in 2026, the brackets are: 10% on income up to $11,925; 12% from $11,925 to $48,475; 22% from $48,475 to $103,350; 24% from $103,350 to $197,300; 32% from $197,300 to $250,525; 35% from $250,525 to $626,350; and 37% on income above $626,350. Married filing jointly thresholds are roughly double. These brackets were made permanent by the One Big Beautiful Bill Act (OBBB, P.L. 119-21) signed July 4, 2025, with annual inflation adjustments continuing. Source: IRS 2026 brackets.

Why Your Marginal Rate Matters for Financial Decisions

Your marginal rate directly affects the value of deductions, the cost of additional income, and retirement contribution strategies. A $1,000 deduction saves you $220 if your marginal rate is 22%, but $370 if you're in the 37% bracket. Similarly, a $10,000 bonus costs $2,400 in federal tax at the 24% marginal rate. Understanding your marginal bracket helps you decide between traditional (pre-tax) and Roth (after-tax) retirement contributions, evaluate whether to accelerate or defer income, and calculate the true after-tax return on investments. Use our effective tax rate calculator to see your blended average rate across all brackets.

Marginal Rate and the OBBB Changes

The One Big Beautiful Bill Act (P.L. 119-21) permanently extended the seven-bracket structure originally introduced by the Tax Cuts and Jobs Act. Prior to OBBB, these rates were set to revert to pre-2018 levels (10%, 15%, 25%, 28%, 33%, 35%, 39.6%) after 2025. The estate tax exemption was raised to $15 million for 2026, not reduced as previously expected. Annual inflation adjustments use the Chained Consumer Price Index (C-CPI-U), which typically grows slower than the traditional CPI.

Marginal Tax Rate Calculator: Traditional vs Roth Retirement Contribution Decision

Your marginal tax rate is the single most important input in the traditional-vs-Roth 401(k) decision — the choice that swings retirement outcomes by six figures over a career. Simple rule: if your CURRENT marginal rate is HIGHER than your EXPECTED retirement marginal rate, use traditional (pre-tax). If your current is LOWER, use Roth. Example: a single earner making $180,000 sits in the 24% bracket now; retirement income projection at $100,000 (drawing 401(k) + Social Security) puts them in the 22% bracket — traditional wins by 2 percentage points on every contribution dollar. Reverse case: a 25-year-old earning $60,000 (12% bracket) planning to retire with $150,000+ blended income (24% bracket) — Roth wins by 12 percentage points. Per IRS Roth Comparison Chart, above 32% marginal now → almost always traditional; below 22% → almost always Roth; 22–24% → do the math with this marginal tax rate calculator. Watch: expected retirement rate should include Social Security taxation, state income tax (if moving to no-tax state, factor in), and Medicare IRMAA thresholds. Updated 2026-07-02.

Marginal Tax Rate Calculator: Hidden "Phantom" Brackets Above the Headline Rates

The IRS headline brackets (10/12/22/24/32/35/37%) hide "phantom" higher marginal rates for taxpayers phasing through income-tested tax breaks. Real examples where marginal rate spikes 15–20 points above the headline: (1) Social Security taxation phase-in — adding $1 of income can make 85 cents of SS suddenly taxable, effectively 22% + (0.85 × 22%) = ~40% marginal. (2) IRMAA cliff at $103,000 single / $206,000 MFJ 2026 MAGI — one extra dollar over the cliff can trigger a $1,000+ jump in annual Medicare premium (effectively 100%+ marginal on that dollar). (3) ACA premium tax credit phase-out — pre-2025 the 400% FPL "cliff" was worst; OBBB extended the smoother phase-out through 2027 but the marginal rate still spikes 15–20 points in the phase-out zone. (4) Child Tax Credit phase-out at $200K single / $400K MFJ — 5% marginal add-on per $1,000 over threshold. Per the Tax Policy Center Briefing Book, effective marginal rates near phase-out thresholds routinely exceed 50% for middle-income taxpayers. Always check where your income falls relative to these cliffs BEFORE the year-end Roth conversion decision this marginal tax rate calculator informs.