The SE tax math
Self-employment tax = 15.3% on the first $168,600 of net SE earnings (12.4% Social Security + 2.9% Medicare), then 2.9% Medicare on everything above. You deduct half of SE tax as an adjustment to income on Form 1040.
What goes on Schedule C
All 1099-NEC and cash income from your business. Then every ordinary and necessary expense: software, advertising, contractors you paid (issue them 1099-NECs over $600), insurance, supplies, professional fees, and home office.
Don't forget
Pay quarterly estimated taxes (April 15, June 15, Sept 15, Jan 15). Open a SEP-IRA or Solo 401(k) — you can deduct up to ~25% of net SE earnings. Track mileage with a logbook or app (Standard Mileage Rate published annually).
