Check Your Withholding Before December: New Deductions

Picture two neighbors. One has been getting a big refund every spring for years. The other keeps owing a little each April. Both assume next spring will look the same, because their paychecks look the same. But the tax rules changed, and payroll systems and benefit payers do not always change with them.

That gap is what this article is about. Withholding is an estimate your employer or benefit payer makes using the information you gave them on a form. If the rules shift but the form does not, the estimate can drift. Understanding that is a real lightbulb moment: your paycheck is not your tax bill, only a prediction of it.

This is general education, not personal advice. We will walk through how the new deductions work, what the IRS tools do, and how workers and retirees commonly approach the adjustment.

A deduction lowers the amount of income that gets taxed. It is different from a credit, which reduces the tax itself. The law signed in 2025 created or expanded several deductions that apply for tax years 2025 through 2028:

• Additional deduction for people 65 and older: up to $6,000 per eligible person. It begins to phase out when modified adjusted gross income (MAGI) is above $75,000 for single filers or $150,000 for joint filers.
• Qualified overtime pay: a deduction of up to $12,500 ($25,000 for joint filers). It generally applies to the premium portion of overtime required under federal law, not the whole paycheck, and it has income phase-outs.
• Qualified tips: a deduction of up to $25,000 for tips in occupations that customarily received tips, also with income limits.
• Interest on loans for new US-assembled vehicles: up to $10,000, with conditions on the vehicle, the loan and the buyer's income.
• State and local tax (SALT) deduction cap: raised to $40,000 for 2025, rising 1% a year, with a phase-down for higher incomes. This one only helps people who itemize deductions.

Each of these has fine print: which pay counts, which vehicles qualify, how MAGI is figured, and what documentation is needed. Confirm the current eligibility rules at IRS.gov rather than relying on a summary like this one.

A common misconception is that these deductions will simply appear in your take-home pay. In practice, standard payroll withholding is built from the information on your W-4, and some of these items are claimed when the return is filed. That can mean a larger refund next spring rather than larger paychecks now. Whether that is fine or not is a personal preference worth thinking through.

The IRS offers a free online Tax Withholding Estimator on IRS.gov. It is designed to compare what you have paid in so far with what you are likely to owe, and it can suggest how a W-4 might be updated. The estimator has been updated to reflect recent law changes, but check the page for its current status.

Here is how people typically use it:

• Gather documents. A recent pay stub shows year-to-date wages and withholding. Last year's return gives a baseline. Retirees may want recent pension statements, 1099-R information and a Social Security benefit statement.
• Enter income for the whole year, not only what has arrived so far. Year-end bonuses, overtime and any planned retirement account withdrawals all belong in the picture.
• Look for the questions about deductions and credits. The tool asks about items that may be relevant, and the IRS describes how to enter them. Overtime, tips and vehicle interest generally have to be separated from your regular pay, so records matter. Your employer may report some of these amounts on a W-2, but not necessarily all of them.
• Review the result. The estimator shows a projected refund or balance due and, if you are an employee, can point to a W-4 adjustment.

Treat the output as an estimate. It depends on what you entered, and mid-year changes in income can move the result.

The Form W-4 is what you give your employer to tell them how much federal income tax to hold back. You can submit a new one at any time. Some situations where people commonly revisit it:

• Their estimator results show a large expected refund or balance due.
• They started earning overtime or tips, or their hours changed.
• A spouse started, stopped or changed jobs.
• They turned 65, or their household's mix of wages and retirement income shifted.
• They bought a new vehicle with a qualifying loan.

The W-4 has a spot in Step 4(b) for deductions beyond the standard deduction. The IRS instructions explain how that line works, and whether a particular new deduction can be entered there is worth confirming at IRS.gov. Another option the form offers is Step 4(c), which asks your employer to withhold an extra flat dollar amount per paycheck.

Neither direction is automatically better. Some households prefer a refund as a kind of forced savings. Others would rather have the money in each paycheck. Both are legitimate preferences, and a tax professional can help weigh them.

Retirees often have several income streams, and each has its own withholding form:

• Form W-4P covers pensions, annuities and certain retirement account payments. The payer applies it to that payment only.
• Form W-4V covers Social Security benefits. Withholding is voluntary, and the Social Security Administration (SSA) allows a limited set of rates: 7%, 10%, 12% or 22%. The form goes to the SSA, not the IRS.
• Retirement account withdrawals, such as IRA distributions and required minimum distributions (RMDs, which generally start at age 73), usually let you elect withholding with the account custodian.

For retirees, a few factors can make the picture more interesting. Up to 85% of Social Security benefits can be taxable depending on income. The new deduction for people 65 and older may reduce taxable income but phases out at higher incomes. And a retiree who pulls from a pre-tax account in a given year changes their own income level. A hypothetical example, for illustration only: a married couple, both 65, with joint MAGI under the $150,000 threshold may each be eligible for the full $6,000 deduction, for $12,000 total. If their top federal bracket were 12%, that deduction would lower federal tax by roughly $1,440. Their pension payer and the SSA would not know that unless the couple told them through a form, and many retirees would rather confirm the actual rules than rely on a rough illustration.

Retirees who prefer not to have tax withheld can also make quarterly estimated payments using Form 1040-ES. The fourth-quarter payment is generally due in mid-January. Those who want to keep the year-end picture tidy may also read our look at the year-end Roth conversion window, since a conversion changes income and can interact with these deductions.

Here is a useful quirk. For tax purposes, withholding is generally treated as if it were paid evenly throughout the year, no matter when it was actually taken out. That is different from estimated tax payments, which are credited when paid. So a change in withholding late in the year can still count for the whole year, but only if the money actually comes out by December 31.

The catch is arithmetic. If an adjustment is needed to cover a gap and only a few pay periods remain, each remaining paycheck carries a larger share. An adjustment made in January would have spread across twenty-six pay periods. One made in December might be spread across two or three. After December 31, 2026, there is no way to change what was withheld for 2026. The remaining options are to pay at filing time or to deal with a refund.

This is not a reason to panic. Owing a modest amount is manageable, and the IRS generally charges an underpayment penalty only when payments fall short of certain safe harbors. The usual benchmarks are paying at least 90% of the current year's tax or 100% of the prior year's tax (110% for higher-income filers). The IRS explains these rules in Publication 505. It is simply useful to know the calendar when thinking about timing. Our Q4 checkup guide covers other items that often land in the same year-end window.

A few patterns come up often when people review withholding:

• Assuming the deductions apply automatically in paychecks. Payroll software works from the W-4, and several of these deductions are claimed on the return.
• Treating all overtime or tips as deductible. The rules cover specific portions and categories, and records matter.
• Forgetting income phase-outs. A year-end bonus, a Roth conversion or a large withdrawal can change MAGI.
• Updating only one form. A W-4 does not change withholding on a pension, and a W-4P does not touch Social Security.
• Overlooking a spouse's income. Two jobs in one household can leave both employers withholding as if each were the only earner.
• Ignoring state taxes. The federal estimator does not set state withholding, which is handled separately.

People who work part-time later in life may also find our article on going back to work after retirement useful, since wages on top of benefits change the withholding picture.

The main idea is simple: withholding is a forecast, and forecasts need updating when the rules change. Workers can look at the Tax Withholding Estimator and the W-4. Retirees can look at W-4P, W-4V and any account withdrawal elections. Everyone can check IRS.gov for the latest eligibility details on the 2025 to 2028 deductions, and review state withholding separately.

Important disclaimer: fidser. is not a registered investment adviser, financial planner or tax professional, and this article is general education, not personalized advice. Tax rules have many conditions and exceptions. Please consult a qualified financial adviser or tax professional before making decisions about withholding, investments or retirement income.