SIT Withheld on your paycheck is the state income tax your employer deducts from your gross pay and sends to your state’s tax agency on your behalf. SIT stands for State Income Tax, and “withheld” means the money comes out before your net pay hits your account. You’ll see it as a line item on every pay stub, and the year’s total lands in Box 17 of your W-2, where it gets applied against whatever you actually owe the state when you file.
The system works the same way federal withholding does. Instead of writing one large check to your state in April, you pay in small increments across the year. Your employer handles the calculation, makes the deduction, and remits the money. If the amount withheld ends up higher than your actual state tax bill, you get a refund. If it’s lower, you owe the difference.
What Determines the Amount
Two inputs drive the SIT figure on your stub: the information you gave your employer on a state withholding form, and your gross pay for that period.
Most states use their own version of the federal W-4, where you declare filing status, dependents, and any extra amount you want withheld. A few states let employers pull that data straight from your federal W-4. Filing status carries the most weight. “Married” with several dependents tells the payroll system to withhold less per check, because it assumes more of your income will be offset by deductions. “Single” with no dependents produces the highest withholding rate per dollar earned.
Your gross pay is the other half. Employers plug your earnings into the state’s withholding tables or formulas. In a state with graduated brackets, the first slice of income might be withheld at 2% while income above a higher threshold gets withheld at 5% or 6%. Flat-rate states skip the brackets. Pennsylvania, for example, applies 3.07% to all taxable wages regardless of income.
State rates vary widely. Some graduated states top out above 10% for high earners; flat-rate states charge everyone the same percentage. Brackets and rates change periodically, so your state’s department of revenue is the place to check current numbers.
When You’ll See $0 for SIT
Nine states don’t tax wages, so employees there see nothing on the SIT line:
- Alaska
- Florida
- Nevada
- New Hampshire
- South Dakota
- Tennessee
- Texas
- Washington
- Wyoming
New Hampshire historically taxed interest and dividend income but not wages; that tax phased out fully as of 2025, so residents now face no state income tax on any income type. Washington has no traditional wage income tax but does impose a separate capital gains tax on certain high-value investment sales.
Living in a no-tax state doesn’t mean your stub is free of state-level deductions. Some jurisdictions require withholding for state disability insurance or paid family leave. And in states like Ohio and Pennsylvania, hundreds of cities and school districts levy local income taxes that appear as their own line items, separate from SIT and governed by local rules.
Adjusting Your Withholding
You can submit a new state withholding form to your employer whenever you want. There’s no limit on how often you can update it.
If you consistently get a big state refund each spring, you’re essentially lending the state money interest-free. Reducing your withholding puts more in each paycheck. If you owe every year, increasing your withholding prevents the annual balance due, and it may also help you dodge an underpayment penalty.
Some life events make a review worth doing right away: marriage or divorce, a new child, a second job, or a noticeable jump in income. Any of these can push your actual liability far enough from your current withholding to create a large refund or shortfall. State payroll systems typically apply a new form within one or two pay cycles.
Most state revenue departments post free online withholding calculators. Running one after you file each year is the simplest way to keep the SIT line dialed in.
Working in One State and Living in Another
Cross-border work complicates the SIT line. Two states can each claim a right to tax the same wages, and there are a few ways this gets sorted out.
Reciprocity Agreements
Some neighboring states have reciprocal agreements that let you pay income tax only to your home state, even if you work across the line. When one applies, your employer withholds SIT for your resident state and ignores the work state. You usually have to file a withholding exemption form with your employer to activate it. Without that form, your employer may default to the work state, and you’d untangle it at filing time. These agreements cluster in the Midwest, Mid-Atlantic, and D.C. area; not every bordering pair has one.
No Reciprocity
Without an agreement, your employer typically withholds SIT for the state where you physically work. You then file a nonresident return there and a resident return at home. To avoid double taxation, most home states offer a credit for taxes paid to the work state, usually equal to the lesser of what you actually paid or what your home state would have charged on that same income.
Remote Workers and the Convenience Rule
Remote arrangements have a wrinkle worth knowing. A handful of states, including New York, apply a “convenience of the employer” rule. If you work remotely from your home state but your employer’s office is in New York, New York may tax your full wages as if you earned them there, unless your remote arrangement exists out of business necessity rather than personal convenience. Connecticut, Delaware, Nebraska, Oregon, and Pennsylvania have adopted variations. The practical effect: your employer may withhold SIT for the office state even though you never physically go there, and your home state’s credit may not fully offset the extra tax.
If You’re Self-Employed, SIT Doesn’t Apply
SIT Withheld is a payroll concept. If nobody is issuing you a paycheck, nobody is withholding state income tax. Self-employed people, freelancers, and independent contractors pay their own state income tax through quarterly estimated payments instead.
Most income-tax states follow the same quarterly schedule the IRS uses: mid-April, mid-June, mid-September, and mid-January of the following year. You estimate your annual state liability, split it across those four dates, and send each payment to your state revenue department. Miss a payment or underpay by too much and the state may charge an underpayment penalty.
If you have both W-2 wages and self-employment income, the SIT withheld from your paycheck covers part of your state bill but usually not all of it. Estimated payments fill the gap.
Reconciling SIT at Tax Time
Filing your state return is where the estimate meets reality. You calculate your actual state tax by applying the state’s rates, deductions, and credits to your full-year income, then subtract the total SIT withheld from Box 17 of your W-2. If your employer withheld more than you owe, you get a refund. If too little was withheld, you pay the difference.
The best outcome is landing close to zero. A big refund means too much came out of each check, money that could have been in your account earning interest or covering bills. A big balance due means your withholding inputs need adjustment, and it can also trigger an underpayment penalty.
Underpayment Penalties
Most states penalize you when your withholding and estimated payments fall too far short of your actual liability. Thresholds vary, but many states use a framework similar to the federal safe harbor: you generally avoid a penalty if your payments cover at least 90% of the current year’s tax or 100% of the prior year’s tax, whichever is less. Some states raise the prior-year threshold to 110% for higher earners. Penalties are usually calculated as interest on the underpaid amount for each quarter you fell short, not as a flat fine.
The cleanest way to avoid all of this is to review your withholding after each year’s return, run your state’s calculator, and file a fresh withholding form early in the new tax year if the numbers say you should.