Year-end tax moves for 2026: a checklist with the numbers, before December 31

A few tax moves only work if you make them before December 31, not April 15. None of the numbers below are generic: each comes from a calculator already checked on this site, or is worked out in full with the arithmetic shown. Run your own numbers in the linked calculators; this is an illustration, not tax advice.

1. Take your RMD by December 31

If you're required to take a minimum distribution from a traditional IRA or 401(k), it's due by December 31 — except for your very first RMD, which you're allowed to delay to April 1 of the following year (at a cost: both that one and the next year's are then taxed in the same year). That exception, the IRS Uniform Lifetime Table, and the full divisor-by-age table are in the RMD table guide; figure your own in the RMD calculator.

The reason not to miss it: someone with $500,000 in an IRA at the end of 2025, turning 73 in 2026, owes an RMD of $500,000 ÷ 26.5 = $18,867.92. Miss the deadline and the shortfall is hit with a 25% excise tax — $4,716.98 here — reduced to 10% ($1,886.79) if you take the missed amount and file a corrective return within two years, under SECURE 2.0.

2. QCD vs. cash gift, also by December 31

If you're 70½ or older, money sent directly from your IRA to a qualified charity (a QCD) counts toward your RMD but isn't taxable income — unlike taking the RMD as income and writing a check. The mechanics, the $111,000 annual QCD limit for 2026 and the new non-itemizer charity deduction are in the QCD vs. cash gift guide; run your own in the QCD calculator.

A fresh example: a single filer in the 24% federal bracket, taking the standard deduction, gives $6,000 to charity. As a QCD, none of it is taxable income. As cash, the $6,000 is included in income when the RMD comes out, and only $1,000 of it is deductible (the 2026 non-itemizer cap for single filers), so $5,000 is taxed at 24% — $1,200 more tax than the QCD, and $6,000 more AGI.

3. Spend your FSA, or know your carryover, by the deadline

A health FSA is still mostly use-it-or-lose-it. The 2026 contribution limit is $3,400, and the most a plan can let you carry into 2027 is $680 — check your own plan, since not all offer a carryover, and some offer a grace period instead. Figures and a full worked election are in how much to put in your FSA; run your own costs in the FSA calculator.

If $950 is left unspent at year-end and your plan allows the maximum $680 carryover, $680 moves to 2027 and $270 is forfeited. With no carryover and no grace period, the whole $950 is lost. Either way, check your plan's exact deadline for incurring (or submitting) claims — it isn't always December 31.

4. Max out your HSA or 401(k) if you're close to the limit

Both are payroll deductions, so once the year's paychecks run out, so does your chance to use that year's limit. The 2026 401(k) limit is $24,500 ($8,000 more from age 50, $11,250 more at age 60–63); figures and contribution-rate tables are in how much to put in your 401(k) by age and the 401(k) match calculator. The 2026 HSA limit is $4,400 self-only / $8,750 family (plus $1,000 from age 55); the partial-year and last-month rules are in the HSA partial-year guide, and the HSA calculator and HSA contribution limit calculator work your own numbers.

Two examples, each with 6 paychecks left between now and December 31 on a semi-monthly schedule:

Both just divide the room left by the paychecks left. If your plan doesn't allow a mid-year change, or your remaining paychecks are too small to reach the limit, the calculators above show the most you can still get in.

5. Roth conversion: fill the bracket, don't overflow it

Converting traditional IRA money to a Roth is taxed as ordinary income the year you do it. A common year-end move is to convert just enough to use up room in a low bracket before it ends. The 2026 single-filer brackets (from IRS Rev. Proc. 2025-32, matching the income tax calculator and the 2026 brackets guide) tax income up to $12,400 of taxable income at 10%, the next slice up to $50,400 at 12%, and the next slice up to $105,700 at 22%.

Example: a single filer with $50,000 of wages and the $16,100 standard deduction has $33,900 of taxable income before any conversion — already past the 10% bracket, inside the 12% one. The top of the 12% bracket is $50,400 of taxable income, so there's $50,400 − $33,900 = $16,500 of room left in it.

Converting exactly $16,500 costs $1,980, all at 12%. Converting $20,000 instead costs $2,750: the first $16,500 still costs $1,980 at 12%, but the next $3,500 costs $770 at 22% instead of the $420 it would have cost at 12% — $350 more, just for crossing the line. The dollar right after $50,400 of taxable income costs 22 cents of tax; the dollar right before it costs 12 cents. Converting past the top of a bracket isn't wrong, but it should be a choice, not an accident — know where your bracket ends before you call your custodian.

One more caveat if you're on Medicare or will be within two years: a conversion raises this year's MAGI, and Medicare uses MAGI from two years ago to set IRMAA, the income-related surcharge on Part B and Part D premiums. The tax bracket and the IRMAA tier are different lines — filling the 12% bracket says nothing about whether you've also crossed an IRMAA threshold. See the IRMAA guide and the IRMAA calculator before finalizing a conversion amount.

If you're already receiving Social Security, both a Roth conversion and an RMD taken as cash raise this year's "provisional income" directly, which is what decides how much of your Social Security benefit is federally taxable -- up to 85% of it, under IRS Publication 915's Worksheet 1. A single filer with $20,000 in benefits and $30,000 of other income already owes tax on $9,600 of that benefit (48%); enough extra income from a conversion or RMD can raise that percentage further. See how much of your Social Security is taxable and run your own numbers in the Social Security taxability calculator before sizing either move.

6. Harvest tax losses, and watch the 30-day wash-sale window

Selling an investment at a loss before December 31 locks in a capital loss for 2026. Realized losses offset realized gains dollar for dollar; if losses exceed gains, up to $3,000 of the excess ($1,500 if married filing separately) offsets ordinary income this year, and anything beyond that carries forward to future years indefinitely.

Example: $8,000 of realized losses and $2,000 of realized gains this year. The gains are fully offset: $8,000 − $2,000 = $6,000 net loss. Of that, $3,000 is deducted against 2026 ordinary income; the remaining $6,000 − $3,000 = $3,000 carries forward to 2027 and later years.

The catch is the wash-sale rule: if you buy the same or a "substantially identical" security within 30 days before or after the sale that produced the loss, the loss is disallowed for now (it's added to the basis of the new shares instead). That 30-day window spans the sale date on both sides, so a loss sold on December 20 isn't safe until January 20 if you're planning to buy back in.

The checklist

A few of these interact: a bigger Roth conversion raises this year's taxable income, which can push a charitable gift toward the QCD side of the comparison in move 2, and a 401(k) contribution lowers the AGI that move 5's bracket math starts from. Work through them in the order your numbers are most certain — RMDs and FSA deadlines first, since those are fixed amounts and fixed dates; the Roth conversion last, since it's the one you have the most room to size exactly.

Every figure above is either drawn from a calculator already checked on this site (linked where it's used) or computed from published 2026 figures with the arithmetic shown. It's an illustration, not tax advice; a real return has details — state tax, other income, phase-outs — these examples leave out.