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• Spend tax-deferred next because deferred income eventually pays ordinary-rate tax regardless of when withdrawn.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.