Most retirement tax mistakes aren’t dramatic. They are small decisions, like taking a withdrawal in the wrong year, ignoring an RMD or forgetting about Medicare thresholds, that quietly cost thousands over a retirement. The good news is that nearly all of them are avoidable with a little planning.
Here are ten of the most common retirement tax mistakes, and what to do instead.
1. Treating all retirement income the same
A pension, a traditional IRA withdrawal, a Roth withdrawal, a capital gain and a Social Security check are all taxed differently. Withdrawing $50,000 from a traditional IRA creates $50,000 of taxable income; taking it from a Roth creates none; selling investments in a brokerage account may create only a small gain taxed at 0%. Instead: map every income source by tax type before deciding where to draw from. See how retirement taxes work.
2. Leaving low tax brackets empty
Many retirees have a few years of very low income between leaving work and starting Social Security or RMDs, and then do nothing with them. Instead: use those years to take IRA withdrawals or Roth conversions up to the top of the 12% or 22% bracket.
3. Ignoring RMDs until they arrive
Required minimum distributions start at 73 (75 for those born in 1960 or later). A large IRA can force big taxable withdrawals on top of Social Security for the rest of your life. Missing an RMD triggers a 25% excise tax on the shortfall (10% if corrected promptly). Instead: plan for RMDs years ahead. See RMDs and taxes.
4. Forgetting that withdrawals make Social Security taxable
Up to 85% of your benefit can be taxable depending on your other income, and the thresholds haven’t changed since the 1990s. An extra IRA withdrawal can make more of your benefit taxable at the same time. Instead: check provisional income before large withdrawals. See how Social Security is taxed.
5. Tripping a Medicare IRMAA threshold
In 2026, Medicare premiums jump once income from two years earlier passes $109,000 (single) or $218,000 (married). Go $1 over and you pay the whole surcharge. Instead: size conversions and sales to stay below the next tier. See what IRMAA is and how to avoid it.
6. Following the textbook withdrawal order rigidly
“Taxable first, then traditional, then Roth” can leave you with a huge IRA and high-bracket RMDs in your 80s. Instead: blend withdrawals across accounts each year to keep taxable income steady. See tax-efficient withdrawal strategies.
7. Not withholding enough tax
Without a paycheck, nothing is withheld automatically from Social Security, and IRA withholding may be too low. Many new retirees face a large bill and an underpayment penalty in their first April. Instead: set withholding on IRA or pension payments, file Form W-4V for Social Security, or make quarterly estimated payments.
8. Writing checks to charity instead of using QCDs
From 70½, a qualified charitable distribution sends money directly from your IRA to charity, up to $111,000 in 2026. It counts toward your RMD and never appears in your income, which beats deducting a check, especially if you take the standard deduction.
9. Cashing out or rolling over incorrectly
An indirect rollover that misses the 60-day deadline, or a 401(k) cashed out on leaving a job, becomes fully taxable, often with a 10% penalty before 59½. Instead: always use direct rollovers. See our rollover guide.
10. Forgetting the survivor
When one spouse dies, the survivor usually files as single from the next year, with roughly half the brackets and thresholds but much of the same income. Instead: plan conversions and withdrawals while both spouses are alive. See retirement tax planning for couples.
A simple yearly routine
- List expected income for the year by source and tax type.
- Check where you land against tax brackets, the 0% capital gains ceiling, Social Security thresholds and IRMAA.
- Decide on conversions, extra withdrawals or gain harvesting to use any spare room.
- Set withholding or estimated payments.
- Review again in the autumn, before the year closes.
The bottom line
Retirement tax mistakes are rarely about one bad decision. They come from not looking ahead. A one-page income map and a yearly review prevent most of them.
Want the full playbook? The Essential Retirement Tax Strategy Guide walks through withdrawal order, Roth conversions, RMDs and Medicare thresholds in plain English, with worked examples.
This article is for education only and is not tax or financial advice. Review major decisions with a qualified professional.
