W-4, Side-Income & Taxes for Teens

Two forms rule your first job: the W-4 you fill out on day one, and the tax return you may (or may not) need to file in April. Both are easier than the rumors say.

How Should a Teen Fill Out a W-4?

The W-4 tells your employer how much federal tax to hold back. For a single teen with one job and no dependents: Step 1, fill in your info and check “Single”; skip Steps 2–4; sign Step 5. Done. That default treats you correctly at almost any teen income.

The “exempt” move: if you had no tax liability last year and expect none this year (true for most students earning under the $16,100 standard deduction), you can write “Exempt” below Step 4(c) — then no federal income tax is withheld at all, and there’s nothing to claw back later.[1] Exempt status must be renewed each year by February 15, and it does not stop FICA — nothing stops FICA, which is explained line by line on the pay stub page.

Side-Income for a Child

For most kids, the first money does not arrive on a pay stub at all. It arrives as cash for mowing a lawn, a Venmo transfer for babysitting, or a payout from reselling sneakers. There is no employer, no W-4, and no withholding — which feels simpler and is actually the opposite. Side income is self-employment income, and the tax rules for it start at a far lower number than most families expect.

The threshold to know is $400. Clear $400 of net self-employment earnings in a year — what you took in minus what you legitimately spent to earn it — and you are required to file a return, even though a teen with the same amount in W-2 wages would owe nothing and file nothing.[2] The reason is self-employment tax: with no employer to pay the other half of FICA, you owe both halves, 15.3% of net earnings, on top of any income tax. That is the entire surprise, and it is why the record-keeping matters more here than anywhere else in a teen’s financial life.

Keeping records is the whole job

Cash work has no paper trail unless you make one, and that cuts in two directions. Without records you cannot subtract your expenses, so you pay self-employment tax on money you never really kept. And without records you cannot prove the earned income that unlocks a custodial Roth IRA — the single most valuable thing a working teenager can do with a dollar.

What a usable record looks like: the date, who paid you, what the job was, and the amount, written down the day it happens. Then the other column nobody keeps — what you spent to do the work. Gas and blades for the mower, poster board and printing for flyers, the shipping and platform fees on a resale, the cost of the inventory itself. Those are deductible against your income, and unrecorded they are simply lost.

One more habit that costs nothing: open a separate savings account for the tax money and move the set-aside percentage into it every time you get paid. A teenager who has spent the tax money by April is learning the same lesson every new business owner learns, only with better odds of recovering. The mechanics of quarterly payments, 1099s, and which expenses actually qualify are in Side Income & the Gig Economy.

Does a Teenager Have to File Taxes?

How Does a Teen File a First Return?

Gather the W-2, use IRS Direct File or Free File (free at teen incomes). Your W-2 should arrive by mail or will be picked up directly by your employer by January 31st. Answer “yes” to “someone can claim me as a dependent” — that box matters, coordinate with your parents — and file. A refund-only teen return takes under an hour and usually pays better per minute than the job did. Side-gig income is a different animal: records, expenses, and quarterly rules live in Side Income & the Gig Economy.