How Are 401(k) Withdrawals Taxed in 2026?

Traditional 401(k) withdrawals are taxed as ordinary income at your marginal federal rate plus state income tax (if your state taxes retirement income). This is the same tax treatment as wages — no preferential capital gains rates, no special retiree exemptions at the federal level. A retired couple withdrawing $80,000 from a Traditional 401(k) pays roughly $8,700 in federal income tax plus state tax depending on residency. The flat 22% supplemental withholding rate that employers use for 401(k) distributions is just withholding — your actual tax is calculated on your full annual income at filing time.

Roth 401(k) withdrawals are entirely tax-free if you meet two requirements: you're at least 59½ AND the Roth 401(k) account has been open at least 5 years (the 'five-year rule'). Either contributions or rolled-over Roth IRA funds count for starting the five-year clock. Roth 401(k) qualified distributions are excluded from federal income tax, state income tax in most states, and the calculation of Social Security taxation (your Roth withdrawals don't add to provisional income). This makes Roth 401(k) particularly valuable for retirees who want to control their Medicare IRMAA tier exposure and Social Security taxation bracket.

Early withdrawals before age 59½ face a 10% federal early withdrawal penalty on top of any income tax. The penalty applies to both Traditional and Roth 401(k) (Roth penalty applies only to the earnings portion if qualified withdrawal rules aren't met). On a $50,000 early withdrawal, that's $5,000 in penalty alone — before federal and state income tax on the distribution. Total tax cost on a $50,000 early withdrawal for a single filer in the 24% federal bracket plus 5% state can easily exceed $19,500 — nearly 40% of the gross withdrawal.

The exceptions to the 10% early withdrawal penalty are narrow but important. IRC §72(t) allows penalty-free early withdrawals for: substantially equal periodic payments (SEPP) over your life expectancy, separation from service in or after the year you turn 55 (the 'Rule of 55' — applies only to your most recent employer's 401(k)), first-time home purchase up to $10,000 lifetime, qualified higher education expenses, qualified medical expenses exceeding 7.5% of AGI, military reservist callup, total and permanent disability, qualified birth or adoption expenses up to $5,000, qualified disaster distributions, and emergency expenses up to $1,000 (SECURE Act 2.0). Income tax still applies; only the 10% penalty is waived.

Required Minimum Distributions force taxable withdrawals starting at age 73 (born 1950-1959) or 75 (born 1960+) per SECURE Act 2.0. Your RMD equals your prior year-end balance divided by an IRS divisor from the Uniform Lifetime Table. At age 73 the divisor is 26.5 — so a $1 million Traditional 401(k) requires a $37,736 RMD that year. Missing an RMD triggers a 25% excise tax on the shortfall (reduced from 50% by SECURE Act 2.0), reduced to 10% if corrected within two years. Roth 401(k)s lost their RMD requirement starting in 2024 under SECURE 2.0 §325.

The 'tax torpedo' kicks in for retirees whose 401(k) withdrawals push them into Social Security taxation territory. Up to 85% of Social Security benefits become federally taxable when 'provisional income' (other income + 50% of SS + tax-exempt interest) exceeds $44,000 for married filers or $34,000 for single filers. Each dollar of Traditional 401(k) withdrawal can expose another $0.50 or $0.85 of Social Security to taxation — creating effective marginal rates well above your nominal federal bracket. Roth 401(k) withdrawals don't count toward provisional income and avoid the torpedo entirely.

IRMAA Medicare surcharges add another layer for retirees on Medicare. Your Medicare Part B and Part D premiums are means-tested based on your tax return from two years prior. In 2026, the first IRMAA tier hits at $212,000 MAGI for married filers, adding about $84/month per person to Part B premiums. Higher tiers add hundreds more. A large Traditional 401(k) withdrawal in any year can push you over an IRMAA threshold two years later, costing thousands per year for the duration. Roth withdrawals don't count toward MAGI for IRMAA purposes.

State tax treatment of 401(k) withdrawals varies dramatically. Nine states have no income tax at all (Alaska, Florida, Nevada, New Hampshire, South Dakota, Tennessee, Texas, Washington, Wyoming). Three states fully exempt qualified retirement income from state tax: Illinois, Mississippi, and Pennsylvania. Most other states tax 401(k) withdrawals as ordinary income at full state rates. Some states provide partial exemptions for retirees over 65 (e.g., New York exempts the first $20,000 of private pension/401(k) income). Plan where to retire with these state-specific rules in mind.

Strategic withdrawal sequencing can reduce lifetime tax dramatically. The conventional advice (taxable first, then Traditional, then Roth) leaves money on the table. A better approach: fill the 12% federal bracket from Traditional every year, even before you need the cash. Move that money to taxable for spending or Roth for future tax-free growth. This 'bracket filling' uses your lowest brackets while you have them, before RMDs force larger Traditional withdrawals into higher brackets. Strategic sequencing typically saves $50,000-$200,000 over a 30-year retirement compared to the conventional sequence.

Run the numbers for your situation. The 401(k) Calculator on this site projects year-by-year contribution, employer match, and balance growth using real IRS limits. The Retirement Withdrawal Calculator projects taxes on withdrawals across federal, state, and FICA layers. The Withdrawal Sequencer compares conventional, proportional, and strategic bracket-filling approaches side by side. The right strategy depends entirely on your account balances, marginal rates, state, and retirement income mix.

Run this analysis on your actual salary.