Order of Withdrawal: Taxable, Tax-Deferred, Tax-Free

The conventional retirement-withdrawal sequence — spend taxable assets first, then tax-deferred, save Roth for last — appears in textbooks, software defaults, and most "rules of thumb" articles. It is right on average and wrong in detail. A dynamic withdrawal strategy that picks the right account each year typically beats the textbook by between $50,000 and $200,000 over a 30-year retirement.

The textbook logic

The conventional argument:

• Spend taxable first to allow tax-deferred and Roth to compound longer.
• Spend tax-deferred next because deferred income eventually pays ordinary-rate tax regardless of when withdrawn.
• Spend Roth last because Roth has the longest compounding runway and is the most tax-efficient asset to pass to heirs.

The logic is sound when applied at the lifetime average level. At the year-by-year level, it ignores bracket management, RMDs, IRMAA, and Social Security taxability — all of which can be optimized by drawing from different accounts in different years.

The dynamic alternative

The dynamic approach evaluates each year:

1. What is mandatory? RMDs (if age 73+), Social Security (if claimed).
2. What is the marginal tax rate on the next dollar from each account type?
3. Which combination of withdrawals produces the lowest current-year + future-year combined tax?

The answer changes from year to year. The same retiree might draw heavily from Traditional in years 1–8 (to clear pre-RMD bracket headroom), then mostly from Roth in years 9–15 (when RMDs plus Social Security push the marginal rate up), then mixed again post-IRMAA.

Worked example: textbook vs dynamic

A 65-year-old couple with $500K taxable (basis $300K, gain $200K), $1.5M Traditional, $500K Roth. $30K pension. Delaying Social Security to 70 ($60K/year combined at FRA × 124% = $74,400).

Textbook approach: spend taxable in years 1–5 (about $80K/year), tax-deferred years 6–25, Roth years 26+.

• Years 1–5: very low AGI (~$30K pension + capital gains as basis is recovered). Wasted bracket headroom.
• Years 6–10: AGI ~$110K (Social Security at 70 + Traditional withdrawals). Standard taxation.
• Year 8: RMDs begin. Combined RMD + Social Security + remaining Traditional withdrawals push AGI to ~$140K. Solid 22% bracket.

Dynamic approach: Roth conversions years 1–8 to fill the 12% bracket; spend taxable for current cash flow; draw from Traditional only enough to fill the 12% bracket in any year; spend Roth in years where RMDs push into 24%; gift appreciated taxable shares to charity or DAF in high-AGI years.

• Years 1–8: AGI ~$95K (pension + bracket-fill conversion). 12% blended.
• Years 9–25: Roth conversions completed; reduced RMDs; mixed Roth/Traditional withdrawals to stay in 22% bracket.
• Estate: substantially larger Roth balance passing to heirs.

Difference in lifetime federal tax: roughly $130K, with a much larger Roth bequest. The textbook approach is not catastrophic — but it is meaningfully suboptimal.

Tax-character considerations by account

• Taxable account. Withdrawals of basis are tax-free. Realized long-term gains taxed at 0/15/20%. The 0% rate at MFJ taxable income up to ~$96K means low-income early retirees can sometimes harvest gains tax-free. Heirs receive step-up in basis under §1014.
• Traditional IRA / 401(k). Withdrawals 100% ordinary income. RMDs force withdrawals beginning at age 73 or 75. Heirs subject to 10-year drawdown with ordinary-income tax.
• Roth IRA / 401(k). Qualified withdrawals 100% tax-free. No lifetime RMDs (Roth IRA; Roth 401(k) exempt post-2024 under SECURE 2.0 §325). Heirs subject to 10-year drawdown but no tax.

The Social Security and Medicare interactions

• Traditional withdrawals push provisional income up, triggering Social Security taxation (50%/85% under §86).
• Both Traditional withdrawals and Roth conversions push MAGI up, potentially triggering IRMAA brackets (with 2-year delay).
• Roth withdrawals affect neither.

For retirees near the Social Security taxability cliff or an IRMAA bracket, dollar-for-dollar a Roth withdrawal can be worth 10%–30% more than a Traditional withdrawal.

Common mistakes

• Following the textbook blindly. The right answer is rarely "spend taxable for five years, then tax-deferred for twenty."
• Forgetting capital gains harvesting. Years of $30K AGI in early retirement are tax-free-gain harvesting opportunities. The 0% LTCG bracket only opens once.
• Treating Roth as untouchable. Roth is the optimal source for IRMAA-management withdrawals in high-AGI years.
• Failing to recalculate annually. The optimal withdrawal mix changes with portfolio performance, tax law, and household composition. Annual review is not optional.

Sources

• Internal Revenue Code §1014, step-up in basis (Cornell LII): law.cornell.edu/uscode/text/26/1014
• Internal Revenue Code §1(h), preferential rates on long-term capital gains: law.cornell.edu/uscode/text/26/1
• Internal Revenue Code §86, Social Security benefit taxation: law.cornell.edu/uscode/text/26/86
• James DiLellio and Daniel Ostrov, "Optimizing Retirement Account Withdrawals," Financial Services Review, 2017.
• Michael Kitces, "Asset Location vs Withdrawal Sequencing": kitces.com

RetirementCheck101 models multiple withdrawal-order strategies and shows the lifetime tax difference. Explore the free educational tool.