The ideal withholding results in owing little to no tax or receiving a small refund (under $1,000) when you file. Large refunds mean you're over-withholding, while owing significant amounts means you're under-withholding.

If you don't withhold enough, you may owe taxes when you file and could face underpayment penalties. The IRS requires you to pay at least 90% of the current year's tax or 100% of last year's tax (110% if your prior year AGI exceeded $150,000).

Yes, you can submit a new W-4 form to your employer at any time to adjust your withholding. Changes typically take effect with your next paycheck or within a few pay periods.

The new W-4 form (2020 and later) no longer uses allowances. Instead, it uses a more straightforward approach with filing status, dependents, and additional income or deductions. For older W-4 forms, claiming fewer allowances results in more tax being withheld.

The Child Tax Credit is worth up to $2,000 per qualifying child under 17. This credit reduces your tax liability dollar-for-dollar, so having dependents typically means you can withhold less from each paycheck.

Multiple jobs can push you into higher tax brackets. Use the IRS W-4 calculator or our tool to account for all income sources. You may need to withhold additional tax from one job or make quarterly estimated payments.

For 2025, the standard deduction amounts are: $15,000 for single filers, $30,000 for married filing jointly, $22,500 for head of household, and $15,000 for married filing separately. These amounts are adjusted annually for inflation.

Review your withholding annually and whenever you experience major life changes such as marriage, divorce, birth of a child, job change, or significant income changes. The IRS recommends checking your withholding at least once a year, preferably early in the year.