Every January, I hear the same regret from friends and colleagues: “I wish I had known about that before the year ended.” Tax planning has a hard deadline, and most of the best strategies expire on December 31 with no extensions, no exceptions, and no do-overs.
I used to be one of those people who did not think about taxes until I sat down with a stack of documents in February. Then I started working with an accountant who taught me that tax planning is a year-round activity, and the moves you make in the final months of the year often have the biggest impact. Last year, the five strategies below saved me a combined $4,800 in taxes. None of them was complicated. All of them required acting before the calendar flipped.
Move One: Max Out Your Retirement Contributions
This is the single most impactful tax move available to most workers, and millions of people leave money on the table every year. For 2026, the 401(k) contribution limit is $23,500, with an additional $7,500 catch-up contribution if you are 50 or older. Every dollar you contribute to a traditional 401(k) reduces your taxable income dollar for dollar.
If you have not been maxing out, check your year-to-date contributions in November and calculate how much room you have left. Many employers allow you to increase your contribution percentage mid-year, and some let you make additional lump-sum contributions in the final pay periods.
At a 24 percent marginal tax rate, maxing out a 401(k) at $23,500 saves $5,640 in federal income tax alone. Add state taxes if applicable, and the savings can exceed $7,000. That is real money — not deferred or theoretical, but actual tax dollars you do not pay.
If your employer offers a Roth 401(k) option, the contribution does not reduce current-year taxes but grows tax-free forever. The right choice depends on whether you expect your tax rate to be higher or lower in retirement. If you are unsure, splitting contributions between traditional and Roth gives you flexibility later.
IRA contributions have their own limits — $7,000 for 2026, plus $1,000 catch-up if over 50. Traditional IRA contributions may be deductible depending on your income and whether you have a workplace plan. Roth IRA contributions are not deductible but offer tax-free growth. Both have an April 15 deadline, but getting them done before year-end is simpler and ensures you do not forget.
Move Two: Harvest Your Tax Losses
Tax-loss harvesting is one of the most underused strategies in personal investing. The concept is simple: sell investments that have declined in value to realize a capital loss, then use that loss to offset capital gains or up to $3,000 of ordinary income per year.
If you have a stock or fund in your taxable brokerage account that is worth less than what you paid for it, selling it before December 31 creates a tax loss you can use immediately. If your total losses exceed your gains, the excess carries forward to future years indefinitely.
The key rule to know is the wash sale rule: if you buy a “substantially identical” investment within 30 days before or after the sale, the loss is disallowed. So if you sell an S&P 500 index fund at a loss, you cannot buy another S&P 500 index fund within 30 days. You can, however, buy a total stock market fund or a similar, though not identical, investment to maintain your market exposure.
Last year, I harvested about $8,200 in losses from an international fund that had underperformed. I used $5,000 to offset gains from a real estate investment and $3,000 to reduce my ordinary income. At my marginal rate, that saved about $1,980 in taxes. I reinvested in a different international fund the same day, so my portfolio allocation stayed nearly identical.
Move Three: Make Strategic Charitable Contributions
If you itemize deductions, charitable contributions directly reduce your taxable income. But even if you take the standard deduction — which most filers do since it increased in 2018 — there are strategies that can make charitable giving tax-efficient.
Donating appreciated stock instead of cash is one of the most powerful moves available. If you own a stock that has gained value, donating it directly to a charity allows you to deduct the full market value while avoiding capital gains tax on the appreciation. A stock you bought for $2,000 that is now worth $5,000 gives you a $5,000 deduction and eliminates $3,000 in taxable gains.
If your charitable giving in any single year is not large enough to exceed the standard deduction, consider bunching — concentrating two or more years of donations into a single year to exceed the threshold, then taking the standard deduction in the off years. A donor-advised fund makes this easy: you make a large contribution in the bunching year, take the deduction, and then distribute grants to charities over the following years.
Charitable giving tax strategies can transform generosity from a pure expense into a financial planning tool. The charities receive the same benefit, and you receive a meaningful tax reduction.
Move Four: Use Your FSA Before You Lose It
If you have a Flexible Spending Account for healthcare or dependent care expenses, the money in it typically must be used by December 31, or you forfeit it. Some plans offer a grace period through March 15 of the following year, and some allow a carryover of up to $640, but these features are not universal.
Check your FSA balance in October or November. If you have unused funds, schedule medical appointments, buy prescription glasses or contacts, stock up on eligible over-the-counter items, or get dental work done before the deadline.
FSA contributions are pre-tax, meaning they reduce your taxable income. But that benefit disappears if the money goes unspent. Forfeiting FSA funds is essentially giving yourself a pay cut, and it happens to millions of Americans every year simply because they lose track of deadlines.
Health Savings Accounts, by contrast, have no use-it-or-lose-it provision — funds roll over indefinitely and can be invested for long-term growth. If your health plan qualifies, maximizing HSA contributions ($4,300 for individuals, $8,550 for families in 2026) provides a triple tax benefit: deductible contributions, tax-free growth, and tax-free withdrawals for medical expenses.
Move Five: Review Your Withholding
If you consistently owe money at tax time or receive a large refund, your withholding is wrong in either direction. Owing a large amount can trigger penalties. Receiving a large refund means you gave the government an interest-free loan all year.
The goal is to match your withholding as closely as possible to your actual tax liability. Use the IRS Tax Withholding Estimator with your most recent pay stub and an estimate of your year-end income. If the estimator shows you are significantly over- or under-withheld, submit a new W-4 to your employer before the final pay periods of the year.
Adjusting withholding in November or December can still make a meaningful difference. If you are under-withheld and heading for a tax bill, increasing withholding in the final paychecks can reduce or eliminate penalties because the IRS treats withholding as if it were paid evenly throughout the year — even if it all came from December paychecks.
If you had a life change during the year — a new job, marriage, divorce, a new child, or a home purchase — your withholding almost certainly needs to be updated. These events significantly change your tax situation, and the default withholding set at the beginning of the year may no longer be appropriate.
The Bonus Moves for Higher Earners
If your income is above $200,000, additional strategies come into play. Qualified business income deductions, backdoor Roth IRA contributions, mega backdoor Roth strategies through employer plans, and net investment income tax planning all have year-end components that require attention.
For self-employed individuals, establishing and funding a SEP IRA or Solo 401(k) before year-end can shelter significant income from taxes. A Solo 401(k) allows combined contributions of up to $69,000 in 2026 for those over 50 — a massive tax deduction for business owners with strong income years.
Do Not Wait Until December 28
The biggest mistake I see is procrastination. People know these strategies exist, but push them too late, to December, when brokerages are processing high volumes, employer payroll departments have limited bandwidth, and charitable organizations may not process gifts in time.
Start your year-end tax review in October. Run the numbers in November. Execute the moves by mid-December. That timeline gives you enough room to handle complications without missing deadlines.
Tax planning is not about gaming the system. It is about using the provisions Congress created specifically to encourage saving, investing, and giving. Every dollar you save in taxes is a dollar you can put to work building your financial future. The rules are there for you — but they only work if you act before the clock runs out.
Image Credit: Pexels
