Most of what you can still change on your 2026 tax return has to happen by December 31, and some of it has to happen earlier, because payroll cut-offs and brokerage trading deadlines fall before the calendar year ends. This checklist is written for women who file as single filers, heads of household, or married couples, and especially for freelancers and small-business owners who do not have an employer managing withholding. The rules changed in 2026 under the 2025 tax law, the One Big Beautiful Bill Act, so some advice that worked last year no longer applies. It is general education, not tax advice.

Start with the number that decides everything: itemize or not

For 2026 the standard deduction is $16,100 for single filers, $24,150 for heads of household, and $32,200 for married couples filing jointly, according to the IRS inflation adjustments for 2026. Most households take the standard deduction, and that decides how the rest of this list works.

Estimate your itemized deductions: mortgage interest, state and local taxes, and charitable gifts. The state and local tax deduction cap is $40,400 in 2026 for most filers, and it shrinks for those with modified adjusted gross income above $505,000. If your total lands well under your standard deduction, itemizing gains you nothing, and charitable giving works differently, which is covered below. If you land close, the timing of gifts and property tax payments can tip the answer.

Harvest losses, but know the limits

If you hold investments in a taxable brokerage account, selling positions that are down can produce capital losses. Losses first offset capital gains of the same kind, then other gains, and if losses still exceed gains you can deduct up to $3,000 of ordinary income ($1,500 if married filing separately) and carry the rest forward. Our guide to tax-loss harvesting covers the mechanics.

Three year-end details matter:

  • The wash-sale rule. If you buy the same or a substantially identical security within 30 days before or after the sale, the loss is disallowed for now. That includes purchases in an IRA, and automatic dividend reinvestment can trigger it without you noticing.
  • Execution timing. The sale has to execute by the last trading day of the year to count for 2026. Do not leave it to the final afternoon, when order delays are more likely.
  • Gains first. If you also have gains to realize, for example from a concentrated stock position or a fund distribution, losses are most valuable when they offset them. A fund that has paid a capital gains distribution in December may have created gains you did not choose, so review your year-to-date statement.

Harvesting does nothing inside a 401(k) or IRA, because gains and losses there are not taxed annually.

Max the accounts that close on December 31

Not every account has the same deadline.

Workplace retirement plans. Elective deferrals to a 401(k) or 403(b) must come out of 2026 paychecks. For 2026 the limit is $24,500, plus $8,000 if you are 50 or older and $11,250 instead for ages 60 to 63. Contact payroll in the first half of November if you need to raise your remaining deferrals, because a change may take a pay cycle or two to take effect. If you are a higher earner age 50 or older, the catch-up portion goes in as Roth money under SECURE 2.0.

IRAs and HSAs. These have a longer window. You can make 2026 contributions to an IRA or HSA until the tax filing deadline in April 2027, so they are not December 31 tasks unless you want the money invested sooner. The 2026 limits are $7,500 for an IRA, plus $1,100 at 50 or older, and $4,400 for self-only HSA coverage or $8,750 for family coverage.

Self-employed plans. Rules for solo 401(k) and SEP plans differ by plan type. A SEP can generally be opened and funded up to the filing deadline, while a solo 401(k) has employee-deferral and plan-establishment timing rules that depend on the plan document and the year it was set up. Confirm the details with your plan provider or tax preparer before December.

Estimated taxes. If you are a freelancer, the fourth-quarter payment for 2026 is due in mid-January 2027. Many women compare year-to-date income with last year in December and find the gap larger than expected. A payment based on actual income is better than a surprise at filing.

The new charitable rules for 2026

The charitable giving rules changed for tax year 2026, and they cut in two directions.

If you take the standard deduction

Beginning in 2026, taxpayers who do not itemize can deduct up to $1,000 of cash gifts to qualifying charities, or $2,000 for married couples filing jointly. This deduction was unavailable to non-itemizers in recent years. It covers cash, check, or card gifts to qualified organizations, and the recipient must be one that qualifies, which you can check in the IRS Tax Exempt Organization Search. Gifts to donor-advised funds do not count, and non-cash gifts such as clothing or appreciated stock are not covered. Keep a bank record or a written acknowledgment showing the organization, amount, and date. The IRS charitable contribution page describes the requirements.

If you itemize

Starting in 2026, only the portion of charitable gifts above 0.5% of your adjusted gross income is deductible. With an AGI of $120,000, the first $600 of gifts yields no deduction. A woman who makes smaller gifts in many years and larger ones in one year might “bunch” them, giving two years of donations in December so her itemized total exceeds the standard deduction, and the floor applies only once to the combined amount. Higher earners in the 37% bracket also face a limit on how much of itemized deductions reduce taxes, which caps their benefit at about 35 cents on the dollar.

Donating appreciated stock held longer than a year, rather than cash, can also avoid the gain, but it does not qualify for the new non-itemizer deduction. If you are 70 and a half or older, a qualified charitable distribution from an IRA can also be an option because it sits outside the 0.5% floor. Those choices depend on your balance sheet, so run them by a tax professional.

A short order of operations

Begin this month by estimating your 2026 income and your standard deduction comparison. In November, adjust payroll deferrals, review realized gains, and harvest losses if they would help. In December, make your charitable gifts early enough to clear before the 31st, and set aside the receipts. A tax preparer can review the numbers with you while there is still time to act on them, which is not true in April.