How to Use the W-4 Withholding Calculator
The W-4 form tells your employer how much federal income tax to withhold from each paycheck. Getting it right means you will not owe a large amount at tax time and will not give the government an interest-free loan through over-withholding.
This calculator projects your annual tax liability based on your pay frequency and gross pay, then recommends the appropriate per-period withholding amount. If your current withholding differs significantly, consider submitting a new W-4 to your employer.
You should update your W-4 whenever you experience a life change: marriage, divorce, new baby, new job, or significant income changes.
Frequently Asked Questions
How often should I update my W-4?
Update your W-4 whenever you have a major life event like marriage, having a child, buying a home, or starting a side job. Also review it annually if your refund or amount owed was significantly different from what you expected.
What happens if I withhold too little?
If you withhold too little, you will owe additional tax when you file your return and may face an underpayment penalty. The IRS generally expects you to pay at least 90% of your tax liability through withholding or estimated payments.
Can I claim exempt on my W-4?
You can claim exempt only if you had no tax liability last year and expect none this year. This is rare for most workers. If you incorrectly claim exempt, you may owe a large amount plus penalties at filing time.
Does the W-4 affect Social Security and Medicare?
No, the W-4 only affects federal income tax withholding. Social Security (6.2%) and Medicare (1.45%) taxes are automatically withheld at fixed rates regardless of your W-4 selections.
My spouse and I both work. How should we fill out W-4s?
Dual-income couples should use the IRS Tax Withholding Estimator or the multiple jobs worksheet on the W-4. Without adjustments, each employer withholds as if that job is your only income, often resulting in under-withholding.