You do a side gig and get paid for it. The full amount is not yours to keep. Tax rules take a share first, no matter how you were paid. This page names the IRS rules, forms, and dates behind that.
It applies whether a customer pays you in cash, by check, or through an app. It applies whether you run a business or work alone with no company name at all.
No one takes tax out for you
A wage job takes tax out of every paycheck. That is called withholding. Self-employment does not work that way. The IRS says a self-employed person pays their own Social Security tax.
They also pay their own Medicare and income tax. No employer withholds it for them. The Social Security and Medicare part has its own name, self-employment tax.
The tax rate: 15.3%
The IRS states the self-employment tax rate is 15.3%. Two parts make up that rate. 12.4% goes to Social Security. 2.9% goes to Medicare.
This tax comes on top of regular income tax. It does not replace income tax. It adds to it.
The $400 line
The IRS says you must file a return once net self-employment earnings reach $400 or more.
Net earnings means what is left after your costs. It is not the full amount a customer paid you.
Two forms: Schedule C and Schedule SE
The IRS names two forms for a self-employed person. Schedule C reports your business income or loss. Schedule SE figures the self-employment tax you owe on that income. Both forms attach to your regular Form 1040 tax return.
Paying the IRS four times a year
A self-employed person often cannot wait until April to pay. The IRS calls this estimated tax. Estimated tax is tax you pay during the year, in parts, instead of all at once. Form 1040-ES is the form self-employed filers generally use to figure it.
The year splits into four periods, each with its own due date. Right now those dates are April 15, June 15, September 15, and January 15 of the next year. A date moves to the next business day if it lands on a weekend or holiday. Check IRS.gov for the current date before you pay.
One part you can deduct
There is a small break in the rule. The IRS lets you deduct the employer-equivalent part of your self-employment tax when you figure adjusted gross income. That is the part an employer would pay if you had one. Adjusted gross income is your income after certain deductions, used to figure income tax.
This lowers your income tax a little. It does not lower the self-employment tax itself. You still owe the full 15.3%.
Cash counts. So does no form at all
Some side-gig work pays in cash, by hand, on the day. That is a normal way to get paid. It does not change the tax rule. The IRS says gig income is taxable even when paid in cash, property, goods, or virtual currency.
The same is true if nobody sends you a form for it. A 1099 is a tax form a business or app may send to report what it paid you. The IRS says gig income must be reported even when no 1099 or other form is issued for it. No form does not mean no tax owed.
Driving for the gig: the mileage rate
Many side gigs mean driving from job to job. The IRS sets a standard mileage rate for business use of a car. For July through December 2026, that rate is 76 cents a mile. An earlier, lower rate applied to the first half of the year.
If you drove for work before July 1, 2026, check which rate covers those miles.
This is not tax advice
This page names rules, rates, and forms. It does not tell you what you owe. Your own income, your state’s rules, and your own costs all change the math. Only you or a tax preparer can work that out for your own return.
For the general rules, IRS.gov is the source. For your own numbers, ask a tax professional.
See what a 1099-K actually reports for the form that reports app and card payments. See what it costs to start a side gig on your own for the other side of the ledger.
Gigs where this matters
These tax rules apply to any side gig where you work for yourself. That includes mowing lawns on your own. It includes cleaning gutters on your own too. It also includes pet sitting on your own.
Each of those gig pages names its own costs and its own tax section. This page covers the tax mechanics that apply across all of them.