Some tax moves count for 2026 only if they're done by December 31; others can wait until you file in April 2027.
This checklist sorts common year-end moves by deadline, using official 2026 IRS figures and the 2025 tax law's changes (Public Law 119-21, the One Big Beautiful Bill Act). Treat each item as something to raise with your tax pro, not a to-do list — whether a move helps depends on your whole return. Law and figures are as of October 18, 2026.
Moves and deadlines at a glance
| Move | Deadline |
|---|---|
| Tax-loss or tax-gain harvesting | Trade executes by Dec 31, 2026 |
| Roth conversion | Completed by Dec 31, 2026 |
| Required minimum distribution (RMD) | Dec 31, 2026 (first RMD: April 1, 2027) |
| Charitable gifts and QCDs | Dec 31, 2026 |
| 401(k) deferrals, extra withholding | Your last 2026 paycheck |
| Q4 estimated tax payment | Jan 15, 2027 |
| IRA and HSA contributions | April 15, 2027 |
Must happen by December 31, 2026
Harvest losses, and respect the wash-sale rule
Selling an investment below what you paid realizes a loss that offsets gains. If losses exceed gains, up to $3,000 of the excess ($1,500 if married filing separately) offsets ordinary income, and the rest carries forward. A sale counts in the year the trade executes, even if it settles in January.
The wash-sale rule disallows the loss if you buy substantially identical securities within 30 days before or after the sale — including in your IRA or Roth IRA, or your spouse's account. Normally a disallowed loss is added to the replacement shares' basis; if the repurchase is inside an IRA, it's gone for good. The capital gains guide covers the mechanics.
Harvest gains into the 0% bracket
In a lower-income year, long-term gains may be taxed at 0% federally. For 2026, the 0% rate covers long-term gains to the extent taxable income, gains included, stays at or below $49,450 for single filers, $66,200 for heads of household and $98,900 for joint filers. Taxable income is after deductions; the 2026 standard deduction is $16,100 single and $32,200 joint. Some investors sell and immediately rebuy to reset their cost basis higher — the wash-sale rule covers losses, not gains. The Capital Gains Tax Calculator shows how much 0% room you have left for 2026; its state estimate covers Virginia only.
Consider a Roth conversion
A conversion counts for 2026 only if it's completed by December 31, and it can't be undone. The converted amount is taxed as ordinary income, so a common approach is filling the bracket: converting just enough to reach the top of your current one. For 2026, the 12% bracket ends at $50,400 of taxable income for single filers ($100,800 joint), 22% at $105,700 ($211,400) and 24% at $201,775 ($403,550).
The extra income has side effects:
- ACA premium tax credit. Under 2026 rules, the credit disappears once household income exceeds 400% of the federal poverty line, and excess advance credits must be repaid in full.
- Medicare IRMAA. Income-related premiums generally use your return from two years earlier, so 2026 income can raise 2028 premiums.
- Capital gains. Conversion income stacks beneath your gains and can push them out of the 0% bracket.
The Roth Conversion and Withdrawal Calculator models conversions year by year alongside RMDs and taxes; the Roth IRA guide covers the account rules.
Take required minimum distributions
For people born 1951 through 1959, RMDs generally start at 73. Each year's RMD is due by December 31, except the first, which can wait until April 1 of the next year — though that means taking two RMDs in that second year. A missed RMD can trigger a 25% excise tax on the shortfall, or 10% if corrected in time.
From age 70½, a qualified charitable distribution (QCD) sends up to $111,000 for 2026 directly from an IRA to a charity. It counts toward your RMD and stays out of taxable income, though you can't also deduct it. Donor-advised funds can't receive QCDs.
Plan charitable gifts under the new rules
Three changes from the 2025 law start in 2026:
- Non-itemizers can deduct up to $1,000 ($2,000 joint) of cash gifts to qualifying charities. Gifts to donor-advised funds generally don't count.
- Itemizers deduct only gifts above 0.5% of AGI. At $200,000 of AGI, the first $1,000 doesn't count.
- Top-bracket itemizers face a new limit: deductions save about what they would in the 35% bracket, not 37%.
Because the floor applies every year, bunching — giving several years' worth in one year, itemizing then and taking the standard deduction otherwise — may be worth a look. A donor-advised fund is one way: the gift is generally deductible when made, and grants can follow later.
Watch the SALT cap and the new deductions
For 2026, the state and local tax (SALT) deduction cap is $40,400. It shrinks by 30% of modified AGI (MAGI) above $505,000, but not below $10,000 (half those amounts if married filing separately).
The 2025 law also added deductions for 2025 through 2028, available whether or not you itemize:
- Age 65 or older: up to $6,000 per person, reduced above $75,000 of MAGI ($150,000 joint)
- Tips: up to $25,000, phasing out above $150,000 of MAGI ($300,000 joint)
- Overtime premium pay: up to $12,500 ($25,000 joint), same phase-out
- Car loan interest: up to $10,000 on a post-2024 loan for a new, U.S.-assembled vehicle, phasing out above $100,000 of MAGI ($200,000 joint)
All of these, SALT cap included, shrink as income rises, so a conversion or gain harvest can quietly cost you some.
Finish workplace retirement deferrals
Workplace plan deferrals come out of paychecks, so only 2026 pay counts toward the 2026 limit: $24,500, plus an $8,000 catch-up at 50 or older, or $11,250 instead for ages 60 to 63. Solo 401(k) owners generally must elect deferrals by December 31, though the deposit can come later.
Check withholding and your FSA
You generally avoid an underpayment penalty if withholding and estimated payments cover 90% of your 2026 tax, or 100% of your 2025 tax — 110% if your 2025 AGI topped $150,000 ($75,000 if married filing separately). Withholding is generally treated as paid evenly through the year, so raising it in your last paychecks can cover an earlier shortfall.
If your health FSA's plan year ends December 31, unspent money is forfeited unless your plan offers a carryover or a grace period of up to 2½ months — one or the other, not both.
Can wait until April 15, 2027
- IRA contributions for 2026: up to $7,500, plus $1,100 at 50 or older; a filing extension doesn't extend it.
- HSA contributions for 2026, if you had HSA-eligible coverage: up to $4,400 self-only or $8,750 family, plus $1,000 at 55 or older.
- The Q4 estimated payment for 2026 is due earlier, on January 15, 2027.
- SEP contributions can wait until your return's due date, including extensions.
Check now for 2027
As of October 18, 2026, the IRS hasn't announced 2027 tax brackets or retirement plan limits. Last year, the 2026 brackets came out October 9 and the 401(k) and IRA limits November 13. Once they're published, it may be worth resetting your payroll deferral rate for January; the 2027 contribution limits guide tracks which figures are official so far.
If you run a calendar-year business, an S-corp election (Form 2553) for 2027 can be filed any time during 2026 or by March 15, 2027. The S-Corp Tax Savings Calculator estimates the payroll tax an election could save at a given salary.
Frequently asked questions
What tax moves have to be done before December 31?
Investment sales for loss or gain harvesting, Roth conversions, RMDs, QCDs, charitable gifts and payroll 401(k) deferrals. IRA and HSA contributions for 2026 can wait until April 15, 2027.
Can I still contribute to an IRA for 2026 in 2027?
Yes, until the 2026 filing deadline — April 15, 2027 for most people. A filing extension doesn't extend it.
Does the wash-sale rule apply if I rebuy in my IRA?
Yes. Buying substantially identical securities in an IRA or Roth IRA within 30 days of a loss sale triggers it, and the loss is lost for good, not deferred.
Do I need to itemize to deduct charitable donations in 2026?
Not for cash gifts. Starting in 2026, non-itemizers can deduct up to $1,000 ($2,000 joint) of cash gifts to qualifying charities. Itemizers deduct gifts above 0.5% of AGI instead.
Disclaimer
This guide is for general educational purposes only and does not constitute personalized financial, tax, or legal advice. Every reader's situation is different — consult a licensed financial advisor, accountant, or attorney before making decisions based on this content. Figures and rules cited here reflect the most recent information available at time of publication and may change; verify current limits and regulations before acting.