Withholding

Withholding is the portion of each paycheck your employer sends directly to the government on your behalf, as an ongoing estimated payment toward your annual income tax liability. It's calculated based on the elections you make on Form W-4, filing status, dependents, and any additional amount you request.

The goal of withholding is to spread your tax payment across the year rather than leaving you with one large bill in April. When your withholding overshoots your actual liability, you get a refund; when it falls short, you owe the difference. The Tax Refund Estimator compares your year-to-date withholding against your projected liability to flag which direction you're headed.

There's no single formula, withholding is computed by employer payroll systems using IRS withholding tables based on your W-4 elections, pay frequency, and gross wages each period.

Someone earning $80,000 a year with standard W-4 elections might have roughly $9,500 in federal income tax withheld over the year. If their actual tax liability comes out to $8,800 when they file:

• Refund: $9,500 − $8,800 = $700

If their liability had instead come out to $10,200, they'd owe the $700 difference instead of receiving a refund.

• A large refund isn't a bonus, it's overpayment. The money was yours all along, withheld and returned without interest.
• Bonuses are often withheld at a flat supplemental rate. This can feel like a bonus is taxed more heavily than regular pay, though it usually evens out when you file.
• Life changes should trigger a W-4 review. Marriage, a new dependent, or a second job all shift your ideal withholding amount.
• Underpayment penalties are avoidable. Paying at least 90% of your current year's liability, or 100-110% of last year's, through the year generally protects you from a penalty.
• State withholding runs on a separate system. Adjusting federal withholding doesn't automatically change what's withheld for state income tax, check both separately if you live in a state with income tax.