Schedule SE (Form 1040) calculates self-employment tax: the Social Security and Medicare tax a self-employed person pays on net profit. Under the 2025 Instructions for Schedule SE you must file it if line 4c (92.35% of net self-employment profit) is $400 or more, or you had church employee income of $108.28 or more.
Part I, in order (2025 form):
- Line 2: net profit from Schedule C line 31 (farm profit goes on line 1a). Line 3: lines 1a + 1b + 2.
- Line 4a: line 3 × 92.35%. Line 4c: if under $400, stop — no self-employment tax (church employee exception).
- Line 6: net earnings from self-employment. Line 7: the pre-printed Social Security wage base — $176,100 for 2025 (the IRS 2026 draft shows $184,500).
- Lines 8a–8d: W-2 Social Security wages and tips (boxes 3 and 7), Form 4137 unreported tips, Form 8919 wages, and their total. The wage base is shared between W-2 wages and self-employment earnings, so a W-2 job reduces the Social Security part. If 8a is $176,100 or more, skip to line 11.
- Line 9: line 7 − line 8d (not below zero). Line 10: smaller of line 6 or 9 × 12.4%. Line 11: line 6 × 2.9% (no cap).
- Line 12: self-employment tax → Schedule 2 (Form 1040), line 4. Line 13: half of line 12 → Schedule 1 (Form 1040), line 15, as an adjustment to income.
Example (2025): $60,000 Schedule C profit, no W-2 wages → $8,477.73 of self-employment tax. The same profit with $150,000 of W-2 Social Security wages → $4,843.29, because only $26,100 of wage base remains for the 12.4% part.
Not on Schedule SE: the 0.9% Additional Medicare Tax is figured on Form 8959. The self-employed health insurance deduction does not reduce Schedule SE earnings. Part II optional methods (farm and nonfarm) have strict eligibility limits in the instructions.
In ExpenseBot: open Year-End → Tax Form Assistant → Schedule SE Details. Enter W-2 Social Security wages + tips (box 3 + box 7) or tick "I had no W-2 wages or tips subject to Social Security tax", plus any Form 4137 tips, Form 8919 wages and church employee income. ExpenseBot then downloads Schedule C and Schedule SE on the official IRS forms (tax years 2021 through 2025 are available). It is for US self-employed filers only — incorporated businesses use their Year-End Expense Summary with their tax professional — and it does not support Part II optional methods or file the return.
Full walkthrough with the line table and worked example: https://www.expensebot.ai/blog/schedule-se-instructions. For a quick estimate, use https://www.expensebot.ai/self-employment-tax-calculator. Estimates — confirm with your tax professional.