Editorâs note: This article first appeared in Money Matters, a newsletter from Britannica Money, on October 11, 2026.
Donât let next springâs tax bill haunt you.
© Andrew Buckin, Surma/stock.adobe.com; Photo illustration EncyclopÊdia Britannica, Inc.
October probably isnât the month that comes to mind when you think about taxesâthat is, if you want to think about them at all. April gets all the attention, and even year-end tax planning feels like something that can wait until December.
But itâs easy to fall into the trap of waiting too long. Some decisions that determine your 2026 tax bill need to be made before the year ends, and a few take time to put in place. By acting now, you may still be able to lower what you owe.
You donât need to wait for your W-2 or 1099 forms to get an idea of what your 2026 taxes might look like. Start with your most recent pay stubs and, if you have other sources of income or expect to itemize deductions, your 2025 tax return.
The IRS Tax Withholding Estimator can do much of the work for you. It asks about your income and the deductions and credits you expect to claim, then estimates whether youâre having the right amount of federal income tax withheld. The Internal Revenue Service says the process takes about 25 minutes.
Pay particular attention to what has changed since last year. A new job, a raise, marriage or divorce, the birth of a child, or another major change in income can throw off your withholding. Investment gains, side-gig income, or a retirement distribution can also make your 2026 return look quite different from your 2025 one.
If the estimate shows youâre having too much or too little withheld, you still have several paychecks left to adjust it. The estimator can even generate a prefilled Form W-4 that you can use to update your withholding through your employer.
April vs. October
April is when you calculate your tax bill. October is when you may still have time to lower it.
Some numbers arenât set yet
Estimating your taxes tells you where you may be headed, but it doesnât mean the outcome is fixed. With about 12 weeks left in the year, there may still be opportunities to reduce your 2026 tax bill.
One of the simplest is saving more for retirement. If you havenât reached the $24,500 contribution limit for your employerâs 401(k) or 403(b) plan, increasing your contributions can lower your taxable income. If youâre 50 or older, you can contribute more, and workers who turn 60 to 63 this year qualify for an even larger catch-up limit.
If you invest, you have another lever. If you sold investments at a profit this year, selling those that have lost value can offset some or all of those gains. If your losses exceed your gains, you can generally use up to $3,000 to offset other income and carry additional losses into future years. Just be mindful of the wash sale rule if you plan to buy the investment back.
Charitable giving can also affect your 2026 taxes. And for the first time this year, taxpayers who take the standard deduction can deduct up to $1,000 in qualifying cash contributions, or $2,000 for married couples filing jointly. To claim the deduction on your 2026 return, the contribution must be made by year-end.
Not everything ends December 31
Some tax moves really do have a year-end deadline. Others give you more time. Knowing which is which can help you decide what needs attention first.
- Check your FSA. If you have money left in a flexible spending account, you may need to use it by year-end. Review your planâs details. Some plans allow unused funds to carry over or offer a grace period, but otherwise you could forfeit whatâs left.
- Fund your 401(k). Contributions through your employer generally need to come out of your 2026 paychecks. If you want to contribute more this year, check how many pay periods you have left.
- Donât forget RMDs. If youâre required to take a minimum distribution from a retirement account, it generally must be taken by December 31. Different rules apply to your first RMD.
- You may have more time. Contributions to traditional and Roth individual retirement accounts and health savings accounts for 2026 can generally be made through April 15, so December 31 isnât your last chance.
What if youâre still coming up short?
Even after considering ways to lower your tax bill, your estimate may show that you havenât paid enough so far. You still have options to close the gap.
- Adjust your withholding. If youâre an employee, you can submit a new Form W-4 to have more tax withheld from your remaining paychecks. The IRS estimator can help determine how much.
- Make a payment. If you have income that isnât subject to withholdingâfrom self-employment, investments, or other sourcesâyou may need to make an estimated tax payment instead.
- Know thy safe harbor. You can generally avoid an underpayment penalty by paying at least 90% of this yearâs tax or 100% of last yearâs tax. If your 2025 adjusted gross income exceeded $150,000, the prior-year threshold generally rises to 110%.
- Donât chase a refund. If the estimator shows youâre having too much withheld, you can also reduce your withholding. A smaller refund means more of your money stays in your paycheck during the year.
Your 2026 tax bill isnât set in stone just yet. By making the most of the time left in the year, April may turn out to be a lot less ghoulish.
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This article was most recently revised and updated by David Schepp
