If you're self-employed in the US, nobody is withholding Social Security and Medicare from a paycheck on your behalf — you owe both halves yourself, and it shows up as a single line called self-employment tax. This calculator takes your net profit from self-employment and works out exactly what you owe for 2026: the Social Security portion, the Medicare portion, and the half of the total you get to deduct when you file.
How it works
Self-employment (SE) tax exists because a traditional employee and employer split Social Security and Medicare taxes 7.65% each, for a combined 15.3%. When you work for yourself, there's no employer to pay the other half, so the IRS collects the full 15.3% from you directly through Schedule SE.
The calculation doesn't start from your raw net profit, though. The IRS first reduces it to 92.35% of net profit — a stand-in for the fact that an employee's wages are never taxed on the employer-paid share of FICA in the first place. That reduced figure, the taxable base, is what the two rates actually apply to: 12.4% for Social Security, capped at the annual Social Security wage base, and 2.9% for Medicare, which has no cap. The calculator rounds each portion to the cent, then adds them for your total SE tax, and finally reports half of that total — the amount deductible on Schedule 1.
Worked example
Say your net profit from self-employment this year is $60,000.
- Taxable base: $60,000 × 92.35% = $55,410
- Social Security portion: $55,410 × 12.4% = $6,870.84
- Medicare portion: $55,410 × 2.9% = $1,606.89
- Self-employment tax: $6,870.84 + $1,606.89 = $8,477.73
- Deductible half: $8,477.73 × 50% = $4,238.87
Every figure here is already rounded to the cent before the next step uses it, so the self-employment tax always equals its two portions added together exactly — there's no unrounded number hiding behind the total. At $60,000 in net profit, none of the taxable base gets anywhere near the Social Security wage base for 2026, so the full 12.4% applies without any cap kicking in.
How to interpret your result
The headline number is your total self-employment tax — what you'll report and pay via Schedule SE, on top of whatever federal (and state) income tax you owe on the same profit. The Social Security and Medicare portions are broken out so you can see how the total splits, which matters most once your net profit is high enough that the Social Security wage base starts capping that portion while Medicare keeps growing uncapped.
The deductible half isn't money back — it's an adjustment to income. You claim it on Schedule 1, and it reduces the net profit your income tax gets calculated on, which softens the double hit of paying both income tax and SE tax on the same self-employment earnings. Keep it handy for when you (or your tax software) get to that line.
Treat this as an estimate of federal self-employment tax only. It doesn't include federal or state income tax, doesn't account for multiple sources of self-employment or wage income in the same year, and isn't a substitute for a tax professional or the IRS's own instructions.
Methodology & sources
The formula follows IRS Schedule SE mechanics: taxable base = net profit × 92.35%; Social Security = 12.4% of the taxable base, capped at the annual Social Security wage base; Medicare = 2.9% of the taxable base, uncapped; total SE tax is the sum of both, each rounded to the cent; the deductible half is 50% of that rounded total. For 2026 this calculator uses a Social Security wage base of $184,500, per the Social Security Administration's 2026 COLA announcement.
See the IRS's own explainer, Self-Employment Tax (Social Security and Medicare Taxes), for the underlying rules, including the current-year wage base and the deduction for one-half of self-employment tax. This tool covers US federal self-employment tax for the 2026 tax year only — not state taxes, not federal income tax, and not personalized advice.