Side hustle & 1099 income tax calculator
A side hustle doesn't get its own tax bracket — it stacks on top of your day job's income and gets taxed at your marginal rate, plus the full 15.3% self-employment tax that your W-2 job doesn't have. See exactly what percentage of every 1099 dollar to set aside.
Use your marginal rate (the bracket your last dollar of income falls into), not your average rate — side hustle income stacks on top of your day job income, so it's taxed at the top of your income, not the average across it.
Self-employment tax on side income
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Income tax on side income (federal + state)
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Total tax owed on side income
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Set aside this % of every payment
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Last updated: September 2026 · Verified by Hugo Cardozo. Uses the IRS/SSA's official 2026 Social Security wage base ($184,500) and the statutory 15.3% self-employment tax rate.
Why side hustle income gets taxed harder than it looks
Your day job already withholds income tax and splits Social Security/Medicare with your employer. A 1099 side hustle has neither: nothing is withheld during the year (so nothing feels "taken out" until tax time), and you owe the full 15.3% self-employment tax — both the employee and employer share — on top of income tax, since there's no employer to cover half.
Why it stacks on top, not averages in
Side hustle income doesn't get blended into an average tax rate — it's taxed starting from wherever your day job income already put you. If your W-2 wages already fill the 12% bracket, your next dollar of side income is taxed at the 22% bracket rate (or whatever bracket comes next), not some blended average of the two. That's why this calculator asks for your marginal rate, not your average one.
How your day job wages affect the self-employment tax portion
The 12.4% Social Security portion of self-employment tax only applies up to the annual wage base ($184,500 for 2026) — and your day job's W-2 wages count against that cap first. If your W-2 wages already meet or exceed the cap, your side income only owes the uncapped 2.9% Medicare portion instead of the full 15.3%. This calculator applies that correctly using your entered day-job wages.
Worked example
With $70,000 in W-2 wages and $20,000 in net 1099 side income, at a 22% marginal federal rate and 5% state rate: self-employment tax on the side income comes to about $2,826, income tax (federal + state, on income reduced by the deductible half of SE tax) comes to about $5,019, for a total of roughly $7,844 — about 39.2% of every side hustle dollar.
What to actually do with this number
Most side hustlers either set aside this percentage in a separate savings account as income arrives, or make quarterly estimated tax payments to the IRS to avoid an underpayment penalty and a surprise bill at filing time. Because nothing is withheld automatically from 1099 income, treating that percentage as already "not yours" the moment it arrives is the most reliable way to avoid a shortfall.
Frequently asked questions
Do I need to make quarterly estimated payments for a side hustle?
Generally yes, if you expect to owe $1,000 or more in tax on the side income for the year — the IRS expects estimated payments in four installments (mid-April, mid-June, mid-September, and mid-January) rather than one lump sum at filing.
Can I deduct business expenses from my side hustle income first?
Yes — this calculator assumes the income entered is already your net profit after deducting legitimate business expenses (supplies, mileage, a home office portion, equipment, etc.). Track those expenses carefully, since they reduce both the income tax and self-employment tax owed.
What if my side hustle grows into my main income?
If the side hustle income approaches or exceeds your W-2 income, it's worth revisiting your overall tax strategy — including whether an S-corp election, a solo 401(k), or a SEP IRA could reduce your tax burden, questions worth discussing with a tax professional at that point.
📘 Related guide
Read the full guide: "Side Hustle Taxes: What Percentage of Your 1099 Income Is Actually Yours".
Side Hustle Taxes: What Percentage of Your 1099 Income Is Actually Yours