A second income
Each employer withholds as though its salary were your only one, so both give you the benefit of the low brackets. Two jobs, or a working spouse, is the most common cause of an April surprise.
2026 tax year · Free tool
Withholding check-up, find out in March, not April
Grab one pay stub. In thirty seconds you will know whether you are heading for a refund or a shortfall, and exactly how much to add or remove from each paycheck to land near zero.
Projected refund
$0
Enter your salary and per-paycheck withholding to see where you land.
Per-paycheck adjustment$0
Ideal per paycheck$0
What to change
Owed versus paid in
The gap between these two bars is your refund or your shortfall.
How we got there
A simplified version of the annual return your withholding is aiming at.
Annual salary$0
Pre-tax deductions for the year$0
Standard deduction$0
Taxable income$0
Tax before credits$0
Child Tax CreditNo qualifying children entered$0
Federal income tax for the year$0
Withheld across the year$0
Educational estimate only, not tax, legal, or accounting advice. Every situation is different; book a consultation for guidance specific to you.
Assumptions used in this calculator
These are the exact 2026 figures this calculator applies.
- Tax year 2026
- Child Tax Credit per child $2,200
- Standard deduction (single $16,100
- Standard deduction) married filing jointly $32,200
- Standard deduction (married filing separately $16,100
- Standard deduction) head of household $24,150
- Single thresholds $12,400 · $50,400 · $105,700 · $201,775 · $256,225 · $640,600
- Joint thresholds $24,800 · $100,800 · $211,400 · $403,550 · $512,450 · $768,700
- Pay frequencies modeled 52 / 26 / 24 / 12
- Deduction method Standard deduction only
How this differs from your employer's calculation: payroll systems use the IRS percentage method from Publication 15-T, which works from your W-4 entries rather than from your actual return. This calculator works backwards from the return itself, which is why it can spot a mismatch your payroll system cannot. Not modeled: state and local withholding, Social Security and Medicare (those are fixed percentages and are not refundable), a second job or working spouse, itemized deductions, other income such as freelance work or investments, the Child and Dependent Care Credit, education credits, and the refundable portion of the Child Tax Credit. Credits are applied only to the extent of tax owed.
Why withholding drifts
Nothing about your W-4 updates itself
The form you filled out on your first day is still running your paycheck. Four things quietly break it.
Side income
Private-pay clients, supervision hours, a course you sell. No employer withholds on any of it, and self-employment tax rides along too.
A life change
Marriage, divorce, a new baby, a child turning 17 and aging out of the Child Tax Credit. Each one moves the target and none of them touches your W-4.
A raise or bonus
Bonuses are often withheld at a flat supplemental rate that may be well below your actual marginal rate, which quietly builds a shortfall over the year.
Related service
If you have practice income as well as a paycheck, withholding is only half the story
A W-2 job and a growing practice means two tax systems running in parallel, and the W-4 was never designed to reconcile them. We set quarterly estimates against your real numbers, adjust withholding to cover what it can, and keep both in step as the year moves.
Questions, answered
About withholding and your W-4
Where do I find my federal withholding on a pay stub?
Look for a line labeled Federal Income Tax, Fed W/H or FITW in the deductions column. Use the current-period amount rather than the year-to-date figure. Do not include Social Security, Medicare, state tax or local tax. Those are separate and none of them is what this calculator projects.
Is a big refund a good thing?
It is a preference, not a tax outcome. A large refund means you lent the government money interest-free for up to a year. Some people genuinely value the forced savings; others would rather have the cash each month. What matters is that the result is deliberate rather than accidental.
How do I actually change my withholding?
Submit a new Form W-4 to your employer. To have more tax withheld, enter the extra per-paycheck amount on line 4(c). To have less withheld, increase the credits on line 3 or the deductions on line 4(b). Most payroll systems apply the change within one or two cycles, so the earlier in the year you act, the smaller the per-paycheck change needs to be.
What if I have a second job or my spouse works?
This calculator models a single salary. Two incomes are the most common cause of under-withholding, because each employer treats its salary as though it were your only one. Enter combined salary and combined withholding for a rough picture, then work through the multiple-jobs worksheet on the W-4 itself, or let us do it alongside your return.
Does this include state tax?
No, federal only. State withholding is a separate calculation with its own brackets, its own certificate and often a local overlay on top. New York City resident tax is a familiar example for our clients.
What happens if I under-withhold badly?
Beyond the bill itself, you can owe an underpayment penalty. The safe harbor is generally paying at least 90% of this year's tax or 100% of last year's, rising to 110% at higher incomes. Because withholding is treated as paid evenly across the year regardless of when it happened, fixing your W-4 in the autumn can still repair an underpayment from January.
I am self-employed, does any of this apply to me?
Only if you also have a W-2 paycheck. If your income is entirely from your practice, you make quarterly estimated payments instead of withholding. Start with the self-employment tax calculator and then the total tax liability estimator. If you have both, one useful trick is to over-withhold on the W-2 job to cover the practice tax, which sidesteps the quarterly-payment timing rules entirely.