Do I owe self-employment tax on a small side hustle?

If your net self-employment earnings reach $400 or more in a year, you owe self-employment tax on them, even from a tiny side hustle, and you must file a Schedule C and Schedule SE. Self-employment tax covers Social Security and Medicare at a combined rate the IRS sets, currently 15.3% on most net earnings, and it applies on top of any income tax. You can deduct half of it as an adjustment to income. Below $400 of net profit, you skip the SE tax but may still owe income tax on the earnings. Because a W-2 job already withholds, side-hustle income often creates a surprise balance due, so set money aside. Estimate the hit with the Self-Employed Hub at wealthserene.com/tools/self-employed-hub.