Direct answer: The biggest 2026 year-end levers with a Dec 31 deadline are retirement contributions (401(k)/IRA), HSA funding, tax-loss harvesting, charitable gifts, and using the $19,000 annual gift exclusion. Under OBBBA 2025, also weigh the SALT cap ($40,400), the $6,000 senior deduction, and the no-tax-on-tips/ overtime deductions.

Source: IRS Rev. Proc. 2025-32; OBBBA 2025 (Pub. L. 119-21). Retrieved 2026-08-11. Not tax advice.

Why year-end timing matters

The U.S. tax system is calendar-year based, which means many planning opportunities close on December 31. Unlike deductions that carry forward (like capital-loss excesses), the contributions and elections listed in this wizard are use-it-or-lose-it for the current tax year. A 401(k) contribution made in January 2027 counts toward 2027, not 2026. An IRA contribution made by April 15, 2027 does count toward 2026 — that is one of the few calendar-year spillover windows.

The second reason timing matters is bracket management. If you know you will itemize in 2026, accelerating charitable contributions into December can push your total above the standard deduction threshold. Conversely, if you expect to itemize next year, deferring a charitable gift to January 2027 may be wiser — but only if your 2027 itemized total will exceed the 2027 standard deduction by a comfortable margin. The wizard helps you model both sides.

A planning checklist for moves that must happen before December 31 to affect your 2026 return (filed in 2027). Toggle what you’ve addressed.

Max out retirement contributions

2026 401(k) employee limit is $23,500 (catch-up extra for 60–63). Traditional contributions cut AGI; Roth gives tax-free growth. Sole proprietors can also deduct employer-side contributions.

Fund an HSA if eligible

Triple tax advantage (deductible, growth, tax-free withdrawals for medical). 2026 family limit is expected near $8,500; confirm the IRS figure.

Bunch charitable gifts

With the high standard deduction, itemizers can “bunch” several years of donations into one year (or a donor-advised fund) to clear the itemizing bar.

Harvest capital losses

Offset up to $3,000 of ordinary income after netting gains; carry the rest forward. Watch the 30-day wash-sale rule.

Consider a Roth conversion

Convert IRA funds in a low-income year; pay tax now to get tax-free withdrawals later. Watch IRMAA and the 5-year rule.

Check QBI before year-end

If SSTB income sits in the 2026 phase-in range ($201,750–$276,750 single / $403,500–$553,500 joint), a retirement contribution can drop you below the start and restore the 20% deduction.

Review estimated-tax payments

Avoid underpayment penalties by checking year-to-date withholdings and payments against your expected liability.

Use the annual gift exclusion

Give up to $19,000 per recipient (2026) free of reporting; married couples can split to double it and move wealth out of the estate.

Not tax, legal, or financial advice

Timing rules, income limits, and phase-outs apply to every item above. This is a reminder list, not advice — coordinate with a CPA/EA before acting, especially on conversions and business deductions.

Frequently asked questions

What tax-saving moves must happen before December 31?
Most 2026 moves have a hard Dec 31 cutoff: 401(k) and IRA contributions, HSA contributions, charitable gifts, tax-loss harvesting, and the $19,000 per-recipient annual gift exclusion. Roth conversions and some business elections can also be timed before year-end. January-dated actions generally count for 2027, not 2026.
How did OBBBA 2025 change year-end planning for 2026?
The One Big Beautiful Bill made the higher brackets permanent and added 2025–2028 breaks: the SALT deduction cap is $40,400 (married $40,400, MFS $20,200 with a phaseout), a $6,000 senior deduction (ages 65+), above-the-line no-tax-on-tips ($25,000) and no-tax-on-overtime ($12,500 single / $25,000 married) deductions, and permanent 20% QBI. Plan around these rather than expired 2017 assumptions.
What is the 2026 standard deduction?
For tax year 2026: $16,100 single and married filing separately, $24,150 head of household, and $32,200 married filing jointly (permanent and indexed under OBBBA 2025). Itemize only if deductions exceed these.
Should I do a Roth conversion at year-end?
A Roth conversion is taxed as ordinary income in the year you convert, but future growth and withdrawals are tax-free. It can make sense if you expect higher rates later or want to reduce a future estate, but it raises your current-year taxable income — model it against the brackets first.
Can I still contribute to an IRA after December 31?
Yes — for 2026 contributions you generally have until the tax filing deadline (April 15, 2027) to make a contribution, provided you had earned income during 2026. The contribution window is separate from the December 31 deadline that applies to 401(k) elective deferrals and HSA contributions.
By: FiscTalk Editorial TeamSourced & checked: In-house, against primary sourcesPublished: 2026-08-09Last reviewed: 2026-08-09

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