If You Claim Single 0, How Much Tax Is Withheld?

If you claim Single with zero adjustments on your W-4 — the current equivalent of the old “Single 0” — a biweekly paycheck in 2026 will have roughly $187 withheld for federal income tax on a $50,000 salary, about $368 on $75,000, and around $579 on $100,000. Social Security and Medicare take another 7.65% of gross pay on top of that, and those payroll taxes are the same no matter what your W-4 says. The exact figure depends on your salary and pay frequency, but this setup still produces the highest default federal income tax withholding available to a single-income filer.

What “Single 0” Looks Like on the Current W-4

The W-4 no longer uses allowances. The IRS eliminated them when it redesigned the form after the 2017 Tax Cuts and Jobs Act wiped out personal exemptions.¹ There is no “0” to enter anywhere on the current form.

To replicate the old “Single 0” setting, check “Single or Married Filing Separately” in Step 1, sign Step 5, and leave Steps 2, 3, and 4 completely blank. The IRS confirms that when only Steps 1 and 5 are completed, withholding is computed using that filing status’s standard deduction and tax rates with no other adjustments.¹ A new employee who never turns in a W-4 gets the same treatment by default.

How Much Comes Out at Common Salaries

Employers calculate withholding using IRS Publication 15-T, which contains rate schedules built around the filing status on your W-4.² Gross pay is annualized, run through the rate schedule for your filing status, and divided back down to a per-paycheck amount. With a “Single 0” setup there are no credits or adjustments to modify the result.

Assuming biweekly pay (26 checks a year) and no W-4 adjustments beyond checking Single, here is what 2026 withholding looks like:

$50,000 salary: about $4,852 in federal income tax withheld annually, or roughly $187 per paycheck.²
$75,000 salary: about $9,562 annually, or roughly $368 per paycheck.
$100,000 salary: about $15,062 annually, or roughly $579 per paycheck.

These come from the 2026 Standard Withholding Rate Schedule for Single filers, which starts at 0% on the first $7,500 of annualized wages and climbs through 10%, 12%, 22%, 24%, 32%, 35%, and 37% on wages above $648,100.²

Walking Through the Math

Take the $75,000 example. The annualized wage is $75,000. Because Steps 2, 3, and 4 are blank, no adjustments are made, so the adjusted annual wage stays at $75,000. That lands in the Single schedule’s $57,900–$113,200 bracket. Base withholding at $57,900 is $5,800, plus 22% of every dollar above that threshold. The excess is $17,100. Twenty-two percent of $17,100 is $3,762. Add that to the $5,800 base and you get $9,562 for the year. Divide by 26 pay periods and each check has $367.77 withheld for federal income tax.

Your stub may differ by a few dollars because some payroll systems use per-period tables rather than the annualize-and-divide method. Both methods come from the same IRS publication and produce close results.

Why This Setup Withholds the Most by Default

Two features combine to make Single with no adjustments the highest default withholding. First, Single applies the smallest standard deduction — $16,100 in 2026, compared with $32,200 for Married Filing Jointly and $24,150 for Head of Household.³ A smaller deduction means more of your income sits in taxable brackets. The Single withholding schedule’s brackets are also narrower than the Married Filing Jointly schedule’s, so you hit higher rates sooner.

Second, leaving Steps 2 through 4 blank tells the payroll system to ignore every tax-reducing factor. Step 3 is where the Child Tax Credit ($2,200 per qualifying child in 2026) and Credit for Other Dependents would reduce tax dollar-for-dollar.⁴ Step 4(b) is where extra deductions would go. Entering nothing means the system withholds at the default rate for someone with no children, no extra deductions, and no favorable filing status.

That’s why the setup almost always produces a refund at filing time. If you qualify for credits, itemize above the standard deduction, or can file under a more favorable status, the Treasury has been holding money it didn’t need all year.

Social Security and Medicare Sit on Top

Federal income tax is only part of what your paycheck loses. Social Security and Medicare — together called FICA — are withheld separately, and W-4 settings have no effect on them. The rates are set by statute.

For 2026, Social Security tax is 6.2% of gross wages up to $184,500.⁵ Once year-to-date earnings pass that threshold, Social Security withholding stops for the rest of the year. Medicare tax is 1.45% of all wages with no cap. If wages exceed $200,000 in a calendar year, an extra 0.9% Medicare surtax applies to earnings above that level.⁶

For someone earning $75,000 biweekly, FICA adds roughly $220 per paycheck on top of the $368 in federal income tax, bringing total federal withholding to about $588. At $50,000, FICA runs about $147 per check. The amount doesn’t change if you’re single, married, or filing under any other status.

When “Single 0” Isn’t Actually Enough

The default assumes you have one job and no other income. If either of those isn’t true, “Single 0” often under-withholds, sometimes by a lot.

More Than One Job

Step 2 of the W-4 addresses taxpayers holding more than one job at a time, or filing jointly with a working spouse. Without a Step 2 entry, each employer withholds as though its paycheck is your only income, and each one applies the full standard deduction’s worth of zero-bracket space. You’re only entitled to that benefit once, so the combined withholding falls short and you’ll see a bill in April.

The IRS offers three ways to fix it:¹

Use the IRS Tax Withholding Estimator at irs.gov/W4app (Step 2a). It produces a dollar amount you enter in Step 4(c) on one job’s W-4.
Fill out the Multiple Jobs Worksheet on page 3 of the W-4 (Step 2b). Less precise than the estimator, but works without internet access.
If you and a spouse have exactly two jobs total, check the Step 2c box on both W-4s. That splits the standard deduction and bracket widths in half for each job.

Interest, Dividends, or Retirement Income

Step 4(a) is where non-wage income that doesn’t have its own withholding gets accounted for. You enter the total annual amount and the payroll system spreads the additional tax across your paychecks.⁴ Don’t include wages from another job or self-employment earnings here — those go through Step 2 or quarterly estimated payments. Ignoring substantial non-wage income is a common reason people who thought they had maximum withholding still owe tax.¹

Withholding More or Less Than the Default

The “Single 0” setup gives you the highest default federal income tax withholding, but it isn’t a ceiling. Step 4(c) lets you add a flat extra dollar amount to every paycheck. Enter $100 there and your employer withholds exactly $100 more than the formula produced. That’s the only way to withhold more than the default.¹

Going the other way, Step 3 lets you claim the Child Tax Credit ($2,200 per qualifying child under 17 in 2026, available to single filers earning $200,000 or less) and the Credit for Other Dependents.⁴ Step 4(b) lets you list deductions you expect to claim above the standard amount, such as mortgage interest or charitable contributions. Both lower withholding.

The IRS Tax Withholding Estimator at irs.gov/W4app is the best tool for setting these numbers. It asks for income, filing status, dependents, and other deductions or credits, then produces a pre-filled W-4 you can print and give to your employer.⁷ Have your most recent pay stub and last year’s tax return handy.

Once you submit a revised W-4, your employer has up to 30 days to put it into effect. The change must take effect no later than the first payroll period ending on or after the 30th day from receipt.⁸ Factor that lag into any mid-year adjustment.

State Income Tax Is Separate

Everything above covers federal withholding only. Most states impose their own income tax, withheld by your employer based on a separate state form or on your federal W-4, depending on the state. Nine states have no income tax at all. Your pay stub should show state withholding as its own line. If the number looks wrong, check whether your employer has the correct state form on file — federal and state forms operate independently.

1
Internal Revenue Service. FAQs on the 2020 Form W-4
2
Internal Revenue Service. Publication 15-T (2026), Federal Income Tax Withholding Methods
3
Internal Revenue Service. IRS Releases Tax Inflation Adjustments for Tax Year 2026, Including Amendments From the One, Big, Beautiful Bill
4
Internal Revenue Service. Form W-4 Employees Withholding Certificate 2026
5
Social Security Administration. Contribution and Benefit Base
6
Internal Revenue Service. Topic No. 751, Social Security and Medicare Withholding Rates
7
Internal Revenue Service. Tax Withholding Estimator
8
Internal Revenue Service. Form W-4, Employees Withholding Certificate