Taxes on a 1099 side gig when you also have a W-2 job
By GigWorkerTax · Updated
Your employer withholds tax from your paycheck, but nobody withholds anything from DoorDash, Uber or freelance pay. The side income lands on top of your wages, so it is taxed at your highest bracket and it carries self-employment tax as well. The good news: you can usually cover it from your paycheck by changing your W-4, without ever making a quarterly payment.
Why a side gig is taxed more than your job, dollar for dollar
Two things stack on side income that your wages do not see in the same way.
It sits at the top of your income. Your wages already use up the standard deduction ($16,100 for a single filer in 2026) and the lowest brackets. Every dollar of profit from the side gig is taxed at the bracket your wages reached, often 12% or 22%, not starting again at 10%.
It carries self-employment tax. On your job, Social Security and Medicare (7.65%) come out of your pay and the employer pays the other 7.65%. On a side gig you pay both halves: 15.3% on 92.35% of your profit. Half of that comes off your income before income tax, and the qualified business income deduction takes up to 20% of the profit off taxable income, which softens the total but does not remove it.
Business costs come off before both taxes. For drivers the largest is mileage: $0.725 a business mile from January to June 2026 and $0.76 from July 1.
An example
Example. A single filer in Texas (no state income tax) earns $52,000 in wages. On weekends they deliver and earn $15,600 over the year, driving 6,500 business miles. At $0.725 a mile the miles are worth $4,713, so the side profit is $10,887.
Without the side gig, their federal tax for the year is $4,060. With it, it is $6,570. The side gig adds $2,510: $1,538 of self-employment tax and $971 of income tax. That is 23.1% of the side profit.
Spread over 26 paychecks, that is about $97 of extra withholding each payday.
The annual calculator works this out for your own numbers: tick that you also have a W-2 job and enter your wages and the tax withheld so far.
Two ways to pay the extra tax
Quarterly estimated payments
You can pay the side-gig tax yourself with Form 1040-ES. For the 2026 tax year the due dates are April 15, 2026, June 15, 2026, September 15, 2026, January 15, 2027. Each payment covers the income of its own period, so a payment made late is late even if the year's total is right in the end.
Extra withholding from your paycheck
The other way is to have your employer withhold more. On a new Form W-4, Step 4(c) "Extra withholding" takes a dollar amount per pay period. Your employer sends it to the IRS with the rest of your withholding, and you need not make any quarterly payment for the side gig.
Withholding has one advantage estimated payments do not: the IRS treats tax withheld from wages as paid evenly through the year, whenever it was actually withheld (Publication 505). If you started the side gig in spring and only noticed in October, raising your withholding for the last paychecks of the year counts as if it had been spread over all twelve months. In the example, 8 paychecks of about $314 cover the year. A quarterly payment made in October cannot do that for the April and June dates.
How to work out the W-4 amount
- Estimate the side profit for the year: what the apps or clients will pay you, less mileage and other business costs.
- Work out the extra tax it adds, as in the example above. The annual calculator shows the total with your wages, and the month and week calculator shows the share to keep from each payout.
- Subtract anything you have already paid for the side gig this year, such as an estimated payment.
- Divide by the number of paychecks left in the year and put that in Step 4(c) of a new W-4. Give it to your employer's payroll.
- Check your next pay stub. Federal income tax withheld should be higher by about that amount.
Step 4(a) "Other income" is meant for income such as interest and dividends: it raises income tax withholding at your rate but does not cover self-employment tax, so for a side business a flat amount in Step 4(c) is the simpler fit. The IRS Tax Withholding Estimator handles self-employment income and suggests a W-4 for you.
Put back the old W-4 in January if you do not want the extra amount next year; a W-4 stays in force until you replace it.
When you do not need to pay during the year at all
The IRS expects payments during the year only when you would owe $1,000 or more at filing time after withholding and credits. Even then there is no underpayment charge if your withholding and estimated payments reach the smaller of 90% of this year's tax or 100% of last year's tax (110% if last year's adjusted gross income was over $150,000). Someone whose job already withholds a little more than their wages need can sometimes cover a small side gig with no change at all. The estimated tax penalty guide explains these rules in full.
Things that change the answer
- High wages. Social Security tax stops at $184,500 of combined wages and self-employment earnings for 2026. Wages count first (Schedule SE line 8a), so if your salary is near that amount, the side gig pays mostly the 2.9% Medicare part.
- Additional Medicare Tax. 0.9% applies to wages and self-employment earnings together above $200,000 ($250,000 married filing jointly).
- A spouse's job. If you file jointly, either W-4 can carry the extra amount. Put it on the paycheck that is largest or most regular.
- State tax. Most states tax the side profit too, and their withholding form is separate from the federal W-4. Texas, used in the example, has no state income tax.
- A loss. If the side business loses money in a year, the loss generally reduces your other income, provided it is a business run to make a profit and not a hobby.
- Under $400 of profit. No self-employment tax is due when net earnings from self-employment are under $400; income tax still is.
What to keep
A side gig is still a business. Keep a mileage log as you drive (date, miles, purpose), the app's yearly earnings summary, every 1099 form, and receipts for anything you deduct. At filing time the side business goes on Schedule C and Schedule SE, next to the W-2 for your job; the Schedule C and SE example fills them in line by line.
Before you rely on it
This page is general information for the 2026 tax year, not tax advice. GigWorkerTax is an independent site, not connected to the IRS or to any gig platform. Every figure the calculators use and its source is on the methodology page; see also the disclaimer, and talk to a licensed tax professional about your own return.
Sources: Form W-4 · IRS Tax Withholding Estimator · Publication 505 · Schedule SE · IRS Gig Economy Tax Center