"Should I claim 0 or 1?" The W-4 no longer works that way

The W-4 stopped using allowances several years ago, so there is no zero or one to claim. What people wanted from zero is still available, but it now lives in a different box.

What "claiming 0" used to mean

On the old form, an allowance was a count. Each one reduced the wages the withholding tables looked at, so a worker who entered fewer allowances had more tax taken out of every paycheck and, usually, a larger refund at the end of the year. Claiming zero was the simplest way to over-withhold on purpose.

That is why the advice existed, and why it is still repeated by people who last filled the form in years ago. The count is gone. There is no line on the current form where a zero or a one would go, and writing one in the margin does nothing.

What replaced it

The current form asks for facts rather than a count. Step 1 takes your name, address, taxpayer number and filing status. Step 2 deals with other jobs, including a working spouse. Step 3 is where dependents and credits go, at $2,200 for each qualifying child under seventeen and $500 for each other dependent. Step 4 holds the three adjustments: other income, deductions, and extra withholding. Step 5 is your signature.

Filled in honestly, those facts land the withholding close to the tax without anyone guessing at a number. Form W-4, line by line walks through what each step asks and where the answers come from.

If you want more tax withheld, use Step 4(c)

Step 4(c) is the line the old advice was reaching for. It takes a dollar amount of additional tax to withhold from each pay period, and the employer adds exactly that to every paycheck.

It is better than the allowance trick in three ways. It is exact, because you choose the amount rather than inferring it from a count. It is per pay period, so you can size it against a known shortfall and multiply. And it does not move when anything else on the form changes. If your aim is the opposite one, a bigger paycheck now, Step 4(b) is where deductions beyond the standard deduction reduce withholding.

The two-job problem

The largest single cause of a surprise bill is two jobs, and it is also the reason the old advice broke. Each employer withholds as though its job were your only income, so each one applies the lower brackets to its own wages. Added together, the two jobs land in a higher bracket than either employer allowed for, and the shortfall shows up in April.

Step 2 fixes it three ways: the IRS estimator, the Multiple Jobs Worksheet on the form, or a checkbox that works when there are exactly two jobs of similar size. If you use the checkbox, it has to be checked on the W-4 for both jobs. And Steps 3 and 4(b) are completed on only one of the forms, not on each.

Claiming exempt, and who actually qualifies

Exempt is not a way to keep more of a paycheck. It is a statement that you had no federal income tax liability last year and expect to have none this year, and both halves have to be true. Someone who owed tax last year does not qualify, however much they would prefer a larger paycheck.

Claiming it when it does not apply means no income tax is withheld all year, so the tax is still owed at filing, and penalties can follow. It also expires. An exemption claimed on a 2026 form does not carry forward on its own; to keep claiming it, a new Form W-4 has to reach your employer by February 16, 2027. Miss it, and the employer starts withholding again.

How to check the result

Run the IRS Tax Withholding Estimator with a recent pay stub for every job in the household and last year's return beside you. The estimator is worth re-running after any change in marital status, jobs, dependents, other income, deductions or credits, and whenever you fill in a W-4 partway through the year. The withholding checkup covers when to do it and what to do with the answer.

What a W-4 does not change

Withholding is a prepayment of tax, not the tax. Changing the W-4 moves money between your paycheck and your refund, and it does not change what you owe for the year by a cent.

A bigger refund bought through Step 4(c) is your own money returned later; a smaller one is the same money earlier. Where your refund comes from sets out the arithmetic, and deductions and credits covers the things that actually change the total.