Sense with Cents

Your employee presents a W-4. Your payroll software calculates federal withholding: $0.00. Is the software faulty? Is zero wrong?

The answer is no on both counts. Here is what is happening.

The 2020 W-4 changed the math

Before 2020, employees claimed withholding allowances on the W-4. Each allowance reduced your withholding. If you claimed zero allowances, you withheld the most.

In 2020, the IRS rewrote the W-4. The form no longer asks the employee to enter allowances — but allowances did not go away. They are now built into the form based on filing status. Each allowance is currently worth $4,300, the same value used in the IRS computational bridge for converting older W-4s. Looking at the 2026 withholding worksheets in IRS Publication 15-T, the implied allowances work out to:

• Married filing jointly: 3 implied allowances ($12,900)
• Single, head of household, or married filing separately: 2 implied allowances ($8,600)
• Step 2 box checked (multiple jobs or working spouse): 0 implied allowances

The employee does not see this on the form. The payroll software applies it behind the scenes.

Note that "filing status" on the W-4 is the employee's choice, not a statement of their actual marital status. An employee can mark single, married filing jointly, married filing separately, or head of household based on how they want their withholding calculated. Someone who is married can mark single on the W-4 if they want more withheld. The W-4 is a withholding tool, not a marriage record.

This especially affects anyone who used to mark "single zero." For decades, single with zero allowances was the standard maximum-withholding choice. Many employees used it — single, married, head of household — to make sure plenty was withheld and they would get a refund at tax time. There is no "single zero" on the new form. Marking single on a plain W-4 with no entries in Steps 2, 3, or 4 effectively gives the employee 2 allowances built in. That can leave them under-withheld by year end, even though they did not change their filing approach.

The new form does have a checkbox in Step 2 for higher withholding, intended for employees with multiple jobs or a working spouse. Checking the box removes the implied allowances and produces noticeably more withholding. We do not see it used often. The amount withheld jumps enough that employees often look at the result and decide it is too much.

Inflation adjustments push more paychecks into the zero range

The IRS adjusts the standard deduction and tax brackets every year for inflation. The same paycheck withholds a little less each year as the brackets creep up. The change is small year to year, but it accumulates — an employee who had a few dollars withheld on a small paycheck one year may see zero withheld on the same paycheck a year or two later.

A different path to zero: the exempt checkbox

There is a separate way an employee can end up with zero federal withholding: claiming exempt. The 2026 W-4 added a dedicated checkbox for this in the area below Step 4. Before 2026, employees wrote "Exempt" in that space by hand.

Exempt is not the same as low-income zero withholding. Exempt is the employee certifying, under penalty of perjury, that they had no federal income tax liability the prior year and expect none in the current year. It is a legitimate option for some employees — but worth a careful look when an employer sees it. For more on the employer's role in handling W-4s and the exempt question, see Employee W-4 and Employer Duties.

The rest of this post is about the other path to zero — the calculated zero on a regular, non-exempt W-4.

Zero withholding shows up more often than employers expect

The federal tax tables have a built-in floor. An employee has to earn a certain amount per pay period before any federal withholding is required. That floor exists because the implied allowances and the standard deduction are already baked into the wage bracket and percentage method tables.

The exact floor depends on filing status, the Step 2 box, and pay frequency. Open IRS Publication 15-T and look at the wage bracket tables. The first several rows of every table show $0 in the withholding column — those are the brackets where the math comes out to zero. A married filing jointly weekly employee, for example, has a much higher zero range than a single weekly employee, because their implied allowances are larger.

A part-time student, a spouse working a small second job, a seasonal hire — all routinely fall in the zero range, and that is the correct answer. If an employee claims dependent credits in Step 3, the zero range goes higher still, because Step 3 reduces the annual withholding directly.

This piece focuses on federal withholding. Some states have similar dynamics — their own standard deductions and tax brackets that result in zero state withholding for low-wage earners. A few states have no income tax at all. State rules are a separate check.

Why your payroll software shows zero

When your payroll software displays "federal withholding: $0.00," it is doing what the IRS requires: calculating withholding based on the wage amount, the employee's W-4, and the tax tables. If the math says zero, the answer is zero.

To verify, check IRS Publication 15-T, Federal Income Tax Withholding Methods. It contains the official tax tables and withholding formulas. That is the standard. Comparing your payroll software to an online calculator or to what another software vendor shows is not a verification — those tools may have their own logic or defaults, and as I discuss in To AI or Not to AI, AI calculators are no exception. Compare to 15-T. If your software matches 15-T, the answer is correct.

The bottom line

Zero withholding is often the correct result of low enough wages on a plain W-4. The rules have changed since 2020. The tax brackets change every year. Your role as an employer is to process the W-4 the employee files.

When your payroll software shows zero federal withholding, trust the math — and verify against 15-T if you want to confirm.

See also: Employee W-4 and Employer Duties and To AI or Not to AI, There Is NO Question.