Taxes feel like an April thing. Mostly they are. But a chunk of the moves that shrink next spring’s bill expire at midnight on December 31, and no amount of scrambling in March brings them back.
The upside: almost none of this is clever. Nudge a payroll contribution. Mail a check to the food bank. Glance at your withholding. That’s the level we’re talking about, and a few rule changes for 2026 make some of these moves more useful to regular households than they used to be.
December 31 or April 15? Sort it first
Some things have to happen this calendar year. Others can wait. Mixing them up is how people end up stressing about the wrong one on Christmas Eve.
| Move | Deadline for tax year 2026 |
|---|---|
| 401(k), 403(b) or 457 contributions (through payroll) | December 31, 2026 |
| Charitable donations | December 31, 2026 |
| Selling investments to harvest losses | December 31, 2026 |
| Required minimum distributions (after the first one) | December 31, 2026 |
| IRA contributions | Tax filing deadline, April 15, 2027 |
| HSA contributions | Tax filing deadline, April 15, 2027 |
| Fourth-quarter estimated tax payment | January 15, 2027 |
And here are the 2026 limits you’ll see referenced below, all from the IRS:
| 2026 limit | Amount |
|---|---|
| 401(k), 403(b), governmental 457 | $24,500 |
| Catch-up, age 50+ (total $32,500) | $8,000 |
| Catch-up, ages 60 to 63 | $11,250 |
| IRA / IRA catch-up (50+) | $7,500 / $1,100 |
| HSA self-only / family / catch-up (55+) | $4,400 / $8,750 / $1,000 |
| Health FSA / max carryover (if plan allows) | $3,400 / $680 |
| Dependent care FSA | $7,500 |
| Annual gift exclusion, per recipient | $19,000 |
| Standard deduction: single / joint / head of household | $16,100 / $32,200 / $24,150 |
| New senior deduction, age 65+ (phases out above $75,000 MAGI, $150,000 joint) | $6,000 per eligible person; up to $12,000 married filing jointly if both spouses qualify |
| SALT deduction cap (reduced when MAGI exceeds $505,000, or $252,500 married filing separately) | $40,400 |
| 0% long-term capital gains rate, taxable income up to (single / joint) | $49,450 / $98,900 |
1. Feed the 401(k) before the last paycheck
Here’s the thing about workplace plans: a 2026 contribution has to come out of a 2026 paycheck. December 31 isn’t the deadline in practice. Your final payday is. So if you want to bump your rate, email HR this week rather than on December 28, when half the office is out.
Fifty or older? The catch-up lets you go well past the base limit. And if you’re 60, 61, 62 or 63, there’s an even bigger catch-up.
Higher earners, one new wrinkle. Made more than $150,000 in FICA wages from your employer in 2025? Then your 2026 catch-up contributions generally have to be Roth. No deduction now; tax-free later, under the usual Roth rules.
2. IRA and HSA: you have until April, but why wait?
Both can be funded for 2026 up until the April 15, 2027 filing deadline. Nice cushion. Still, money parked in checking isn’t doing anything, so if it’s there, put it to work.
Something new on the HSA side, worth a look during open enrollment: as of 2026, bronze and catastrophic plans from a health insurance marketplace are treated as HSA-eligible. We break down the plan choices in our guide to comparing 2027 health plans.
3. That FSA balance won’t spend itself
Every plan handles leftovers differently. Some let you roll over a limited amount. Some give a grace period into the new year. Some? Neither, and the money’s just gone. Log in, see what’s left, read your plan’s rule. Plenty of ordinary stuff counts, from new glasses to the dentist to restocking the bandage drawer.
Pay for daycare? The dependent care FSA limit jumped to $7,500 in 2026, from $5,000. Open enrollment is the time to raise that election.
4. Give, even if you never itemize
Biggest change of the year, in my opinion. Starting in 2026, people who take the standard deduction can still write off cash donations to qualifying charities, up to $1,000 if single and $2,000 if married filing jointly. The catch: gifts to donor-advised funds generally don’t count.
Itemizers, meanwhile, get a small haircut. Only the part of your charitable giving above 0.5% of your adjusted gross income is deductible now.
Whichever group you’re in, the gift has to go out by December 31. Keep a bank record or a written receipt from the charity, and for any single contribution of $250 or more, you also need a contemporaneous written acknowledgment from the organization.
Are you 70½ or older with a traditional IRA? Look up the qualified charitable distribution. The money goes directly from the IRA to the charity, up to $111,000 for 2026, and it stays out of your taxable income.
5. Owe a lot? Fix it with withholding
Good news: December still works. Withholding gets special treatment, because the IRS generally counts tax taken from paychecks as though it trickled in evenly all year. Load up the last few checks and it’s as if you’d been paying the whole time. Estimated payments? Those count the day they land. Big difference.
How much is enough to keep the underpayment penalty off your back? Usually 90% of this year’s tax, or 100% of what you owed last year. If last year’s AGI went over $150,000, make that 110%. How to change your W-4 is covered step by step in our post on adjusting tax withholding.
Freelancer, or living on income with nothing withheld? Mark January 15, 2027: that’s the fourth-quarter estimated payment for 2026. Tips or overtime in your paycheck? Check the new deductions in our guide to no tax on tips and overtime.
6. Losers in your brokerage account can help
Own something in a taxable account that’s down from what you paid? Sell it by December 31 and that loss can cancel out gains. Losses beyond your gains knock up to $3,000 off other income each year ($1,500 married filing separately). Whatever’s left rolls forward.
The trap is the wash-sale rule. Buy the same thing, or something substantially identical, within 30 days on either side of the sale and the loss gets disallowed. Your IRA counts, too, so no sneaky repurchase there.
Quiet income year? Then check the table above, because long-term gains might be taxed at 0% for you. Some people deliberately sell winners in a year like that.
7. The quick-check pile
RMDs. At 73 and up, the required minimum distribution has a December 31 due date, except your very first one, which can wait until April 1 of the next year. Forget it, and you’re looking at a 25% penalty on the shortfall, though fixing it within two years drops that to 10%.
Gifts to the kids (or anyone). Under the annual exclusion in the table, you generally don’t file a gift tax return at all.
Standard deduction and the senior bonus. Both are in the table. Sixty-five or older? Don’t skip the new senior deduction; it’s easy to miss because it’s brand new.
SALT. Live somewhere with steep state and property taxes, and itemize? The cap is a lot roomier than the old $10,000, though it shrinks for very high incomes.
Credits you can stop counting on
Thinking about solar, a heat pump or new windows for the tax break? There isn’t one anymore, federally. The two home energy credits, called the Energy Efficient Home Improvement Credit and the Residential Clean Energy Credit, don’t reach expenses or property placed in service after December 31, 2025. Bought an EV after September 30, 2025? No clean vehicle credit for it, either. Hear a salesperson promise one for 2026? Ask for the IRS page. Politely.
Your short list for this week
- Payroll portal: is your 401(k) rate where you want it for the last few checks?
- FSA: balance, plus your plan’s leftover rule.
- Charities picked, receipts saved, all before December 31.
- The IRS Tax Withholding Estimator, if a balance due seems likely.
- Brokerage account (the taxable one): gains and losses, checked by mid-December. Waiting for the 30th leaves zero room for a mistake.
Disclaimer: This article is for general educational purposes and is not tax, legal or financial advice. Tax rules depend on your situation and can change. Confirm figures on IRS.gov or with a qualified tax professional before acting.
Frequently Asked Questions
January contributions to an IRA or HSA: do they count for 2026?
They can, as long as you tell the provider it’s a 2026 contribution. The cutoff is generally the filing deadline, April 15, 2027.
Standard deduction this year. Can I still deduct what I give?
From 2026 on, some of it. Cash to a qualifying charity, up to $1,000, or $2,000 if you’re married and file jointly. Donor-advised funds? Generally not.
How high can my 401(k) go at 55?
$32,500 for 2026. That’s $24,500 regular plus $8,000 catch-up; between ages 60 and 63, the catch-up jumps to $11,250 instead.
I think I underpaid this year. Is the penalty unavoidable?
Maybe not. Bump up withholding on the paychecks you have left; because withheld tax is generally treated as paid evenly through the year, it can cover the earlier months too.
Is any of this worth it if my income is modest?
Often more than people think. The new charitable deduction, a bit of extra withholding, or using up an FSA can matter more to a tight budget than any fancy strategy.
Sources
- IRS: Tax inflation adjustments for tax year 2026 (IR-2025-103) (www.irs.gov/newsroom)
- IRS: Revenue Procedure 2025-32 (www.irs.gov/pub/irs-drop)
- IRS: 401(k) limit increases to $24,500 for 2026 (www.irs.gov/newsroom)
- IRS: Notice 2025-67 (www.irs.gov/pub/irs-drop)
- IRS: Internal Revenue Bulletin 2025-49, Notice 2025-67 (2026 QCD limit of $111,000) (www.irs.gov/irb)
- IRS: Charitable contributions, written acknowledgments (www.irs.gov/charities-non-profits/charitable-organizations/charitable-contributions-written-acknowledgments)
- IRS: 2026 filing season updates and resources for seniors (www.irs.gov/newsroom)
- IRS: Correction to state and local income tax deduction amount in the 2026 Form 1040-ES (www.irs.gov/forms-pubs)
- IRS: Revenue Procedure 2025-19 (HSA limits) (www.irs.gov/pub/irs-drop)
- IRS: Notice 2026-5 (HSA changes) (www.irs.gov/pub/irs-drop)
- IRS: Publication 15-B (www.irs.gov/publications)
- IRS: Topic 506, Charitable contributions (www.irs.gov/taxtopics)
- IRS: Publication 505, Tax withholding and estimated tax (www.irs.gov/publications)
- IRS: Deductions for working Americans and seniors (www.irs.gov/newsroom/one-big-beautiful-bill-act-tax-deductions-for-working-americans-and-seniors)
- IRS: Required minimum distributions (www.irs.gov/retirement-plans/plan-participant-employee/retirement-topics-required-minimum-distributions-rmds)
- IRS: Energy Efficient Home Improvement Credit (www.irs.gov/credits-deductions/energy-efficient-home-improvement-credit)
- IRS: Residential Clean Energy Credit (www.irs.gov/credits-deductions/residential-clean-energy-credit)
- IRS: Clean vehicle tax credits (www.irs.gov/clean-vehicle-tax-credits)
- Cornell LII: 26 U.S. Code § 164 (SALT cap) (www.law.cornell.edu/uscode/text)
