A meaningful chunk of the average American household's federal tax bill is avoidable with moves made before December 31. Not aggressive loopholes. Not shady maneuvers. Just timing decisions that the tax code explicitly rewards.
The key insight: most tax planning isn't about finding deductions you missed. It's about pulling the right levers in the right order before the calendar resets. Here are 12 moves that work for the 2025 tax year, ranked roughly from simplest to most complex.
The quick version: Max out retirement accounts, harvest investment losses, consider Roth conversions, and review your deduction strategy before December 31. The SALT cap increase to $40,000 changes the math for many homeowners in 2025.
1. Max Out Your 401(k)
The 2025 contribution limit is $23,500 for employees under 50. If you're 50 to 59 or 64+, you can add $7,500 in catch-up contributions. Ages 60 to 63 get a "super catch-up" of $11,250, courtesy of SECURE 2.0.
Every dollar you contribute reduces your taxable income by exactly that much. A worker in the 24% bracket who maxes out at $23,500 saves $5,640 in federal tax. That's not a theoretical number. That's cash you keep.
If you haven't maxed out, contact HR about increasing your December payroll deduction. Some plans let you contribute up to 100% of a single paycheck.
2. Harvest Tax Losses
Review your portfolio for unrealized losses. Selling losing positions offsets capital gains and up to $3,000 of ordinary income. Unused losses carry forward.
This is especially valuable if you had a strong year with realized gains elsewhere. The detailed mechanics, including the wash-sale rule and replacement fund strategy, are in our tax-loss harvesting guide. The short version: sell the loser, buy something similar but not identical (swap VOO for VTI, for instance), and pocket the tax savings.
3. Evaluate the New SALT Cap
Here's the biggest change for 2025 filers. The One Big Beautiful Bill Act raised the State and Local Tax (SALT) deduction cap from $10,000 to $40,000 for joint filers with AGI under $500,000.
This is massive for homeowners in high-tax states. A couple in New Jersey paying $22,000 in property taxes and $16,000 in state income tax previously could only deduct $10,000. Now they can deduct the full $38,000. That's an extra $28,000 in deductions.
Run the numbers. If your state and local taxes exceed the standard deduction when combined with other itemized deductions, itemizing may now save you money when it didn't before.
| Filing Status | 2024 SALT Cap | 2025 SALT Cap | Standard Deduction (2025) |
|---|
| Single | $10,000 | $40,000 | $15,750 |
| Married Filing Jointly | $10,000 | $40,000 | $31,500 |
4. Consider a Roth Conversion
Low-income years are golden for Roth conversions. If your 2025 income is below normal (job change, sabbatical, early retirement), you can convert traditional IRA funds to a Roth at your current low rate.
The conversion creates taxable income, so calculate the optimal amount to fill your bracket without spilling over. Our Roth conversion strategy guide walks through the bracket-filling math step by step.
December is the last month to execute a 2025 conversion. January 1 starts a new tax year.
5. Fund Your HSA
Health Savings Accounts are the only triple-tax-advantaged account in the tax code: tax-deductible contributions, tax-free growth, and tax-free withdrawals for medical expenses. No other account does all three.
The 2025 limits are $4,300 for self-only coverage and $8,550 for family coverage. Unlike 401(k)s, you have until your tax filing deadline (April 2026) to make HSA contributions for 2025. But if you can front-load, the money starts growing sooner.
6. Bunch Charitable Contributions
If you're close to the itemizing threshold, "bunching" two years of charitable donations into one year can push you over. Give $6,000 this year and nothing next year instead of $3,000 each year.
Better yet, use a Donor-Advised Fund. Contribute a lump sum to Fidelity Charitable, Schwab Charitable, or Vanguard Charitable, take the full deduction this year, and distribute the funds to charities over time.
If you have appreciated stock, donate the shares directly. You avoid capital gains tax on the appreciation and get a deduction for the full market value. It's one of the rare moves where everyone wins: you, the charity, and your tax bill.
7. Take Required Minimum Distributions
If you're 73 or older, make sure you've taken your required minimum distribution from traditional IRAs and 401(k)s. The penalty for missing an RMD is 25% of the amount you should have withdrawn (down from 50% under previous rules). Still steep enough to ruin your December.
First-year RMD filers get until April 1 of the following year. But that means doubling up (two RMDs in one year), which can create an ugly income spike. Taking the first RMD by December avoids that.
8. Contribute to a Traditional IRA (If Deductible)
You have until April 2026 to make 2025 IRA contributions. But contributing before December 31 means the money starts growing sooner.
The 2025 limit is $7,000, or $8,000 if you're 50+. Deductibility depends on whether you (or your spouse) have a workplace retirement plan and your income level. If you qualify for the deduction, it reduces taxable income dollar-for-dollar.
9. Check the Senior Bonus Deduction
New for 2025: taxpayers aged 65 and older may qualify for an additional $6,000 deduction (single) or $12,000 (married, both 65+). This phases out at $75,000 MAGI (single) and $150,000 (married).
There's no action required to claim it, it's automatic on your return. But knowing about it matters for planning: if you're near the phase-out threshold, deferring income could preserve the full deduction. Our article on what seniors actually owe on capital gains digs into how this deduction interacts with investment income.
10. Accelerate or Defer Income
If you expect to be in a lower bracket in 2026, defer income. Delay a year-end bonus until January. Push freelance invoices into the new year.
If you expect higher income next year, accelerate income into 2025. Bill clients now. Take capital gains now while your rate is lower.
The OBBBA made 2017 tax rates permanent, so you don't need to worry about rates "expiring" in 2026 as was previously feared. But your personal income level may still change, and that's what matters for bracket management.
11. Review the 20% QBI Deduction
If you have pass-through business income (sole proprietorship, S-corp, partnership), the Qualified Business Income deduction lets you deduct up to 20% of that income. But the deduction has income phase-outs. If you're near the threshold ($191,950 single / $383,900 married for 2025), reducing taxable income through other strategies on this list can preserve the full QBI deduction.
This is one of those deductions where the interaction effects matter more than the deduction itself. Max out your 401(k), fund your HSA, and bunch charitable gifts, and you might slide below the QBI threshold.
12. File Form 4547 for a Trump Account
The OBBBA created a new tax-advantaged savings account for children under 18. By filing Form 4547 with your 2025 tax return, you can elect to receive a $1,000 federal seed deposit for eligible children. Contributions begin in July 2026, but the election happens now.
This is a one-time administrative step. If you have children or grandchildren under 18, the form costs nothing to file and secures the seed deposit.
Your Year-End Checklist
| Move | Deadline | Potential Savings |
|---|
| Max 401(k) | Dec 31 | Up to $5,640 (24% bracket) |
| Harvest losses | Dec 31 | Varies by portfolio |
| SALT deduction review | Tax filing | Up to $7,200 (24% × $30k extra) |
| Roth conversion | Dec 31 | Long-term, compounding |
| Fund HSA | April 2026 | Up to $2,052 (24% bracket) |
| Bunch charitable gifts | Dec 31 | Varies |
| Take RMDs | Dec 31 | Avoids 25% penalty |
| IRA contribution | April 2026 | Up to $1,680 (24% bracket) |
| Senior deduction | Automatic | Up to $2,880 |
| Income timing | Dec 31 / Jan 1 | Varies |
For the full picture on how capital gains interact with these strategies, see our capital gains tax overview. Use our tax bracket calculator to model how each move affects your specific situation. And for a deeper look at how your state adds to the bill, check that guide before making major year-end sales.
References
- Internal Revenue Service. (2025). 401(k) limit increases to $24,500 for 2026, IRA limit increases to $7,500. IRS.gov.
- Vanguard. (2025). Maximize your tax savings with tax-loss harvesting. Vanguard.com.
- HCVT. (2025). SALT Deduction Cap Increase Under OBBBA. HCVT.com.
- Voya. (2025). 2025 HSA Contribution Limits. Voya.com.
- Internal Revenue Service. (2025). Retirement Topics: Required Minimum Distributions. IRS.gov.
- Internal Revenue Service. (2025). IRA Contribution Limits. IRS.gov.
- Internal Revenue Service. (2025). One Big Beautiful Bill Act: Tax deductions for working Americans and seniors. IRS.gov. https://www.irs.gov/newsroom/one-big-beautiful-bill-act-tax-deductions-for-working-americans-and-seniors
- J.P. Morgan. (2025). 5 Year-End Tax Planning Actions to Take Before 2026. PrivateBank.JPMorgan.com.
- Internal Revenue Service. (2025). Qualified Business Income Deduction. IRS.gov.
- TaxSlayer. (2025). Trump Account Form 4547. Support.TaxSlayer.com.
