Side Hustle Tax Calculator 2026

Calculate the real tax impact of your side hustle income stacked on top of your W-2 job — in seconds. Most tax calculators treat your income as one lump. But if you have a day job AND freelance/gig/1099 income, your side hustle dollars are taxed at your MARGINAL rate — not your average rate. This calculator shows you exactly what happens when income stacks. WHAT IT CALCULATES: - Combined federal income tax on W-2 + side hustle income - Self-employment tax (15.3% SECA) on side income - Effective vs marginal tax rate comparison - Quarterly estimated payment amounts - Take-home pay after all taxes - How much each additional $1,000 of side income actually costs in tax FEATURES: - 2026 tax brackets (OBBBA/TCJA permanent rates) - W-2 withholding offset — enter your paycheck withholding to see the GAP you need to cover - Self-employment tax with above-the-line deduction calculated automatically - Standard deduction applied ($15,350 single / $30,700 MFJ) - QBI deduction for qualifying business income - Clean, instant results — no signup, no data collection WHO THIS IS FOR: - Freelancers with a day job - Gig workers (Uber, DoorDash, Instacart) with W-2 employment - Side business owners - Anyone with 1099 + W-2 income wondering "how much of this do I actually keep?" FREE — Federal tax calculation, SE tax, quarterly estimates, take-home breakdown. PRO ($4.99) — Adds state income tax for all 50 states, deduction optimizer, and export. Built by QuantCalc (quantcalc.app) — makers of the Monte Carlo retirement planner trusted by the FIRE community. Your data never leaves your browser. Zero tracking. Zero data collection.