That confusing form your employer gave you on day one — decoded line by line. Fill it out right and avoid both a surprise April bill and a giant refund.
When you start a job, you fill out a W-4 (Form W-4, 'Employee's Withholding Certificate'). It tells your employer how much federal income tax to subtract from each paycheck and send to the IRS on your behalf.
The current W-4 (post-2020 redesign) has five steps:
Nia claimed too many dependents to boost her paycheck and owed $300 + penalty in April. Not worth it.
Key takeaway: Your W-4 tells your employer how much federal tax to hold back from each paycheck. Filling it out thoughtfully means no big surprise bill — and no giant refund (which is just your own money returned, late).
Questions people ask
What's the difference between a W-4 and a W-2?
W-4 is what you fill out when you start a job (tells your employer how much tax to withhold). W-2 is what your employer sends you in January summarizing what you earned and what was withheld — you use it to file your taxes.
Can I claim 'exempt' as a teen?
Only if you owed $0 in federal tax last year and will owe $0 this year. For most teens earning under ~$14,600, yes.
What if I never filled out a W-4?
Your employer is required to withhold at the highest rate (single, no adjustments). You'll likely get a bigger refund — but it's still your own money you let the government borrow.
Does the W-4 affect my Social Security or Medicare?
No. FICA is a flat 7.65% regardless of your W-4. The W-4 only controls federal income tax withholding.
What's the deadline to fix my W-4?
There's no deadline — you can submit a new W-4 to your employer any time during the year. Earlier in the year is better because it spreads the change over more paychecks.
Can I have extra tax withheld if I want a bigger refund?
Yes, via Step 4(c). Not recommended, though. Automating that same extra cash into an HYSA earns you interest instead of lending it to the IRS for free.