The first year of freelancing comes with a memorable surprise. You track your income, set aside something for income tax, and then discover a second tax you never paid as an employee: self-employment tax. It catches people off guard because it’s large — 15.3% in the U.S. — and because, as an employee, half of it was always paid on your behalf without you noticing.
Understanding where that 15.3% comes from, what it’s actually charged on, and how the deductible half softens the blow turns a nasty shock into a predictable line item you can plan around.
Why freelancers owe both halves
Self-employment tax is really Social Security and Medicare — the same FICA contributions withheld from every employee’s paycheck. The catch is that for employees, the cost is split: the worker pays half and the employer pays the other half. That split is 6.2% + 6.2% for Social Security and 1.45% + 1.45% for Medicare.
When you’re self-employed, you are both the worker and the employer, so you owe both halves yourself. Added up, that’s 12.4% for Social Security plus 2.9% for Medicare, or 15.3% total. Nothing new was invented for freelancers — you’re simply paying the portion an employer used to cover.
As an employee you always paid half of Social Security and Medicare; your employer paid the rest. Self-employment tax is just the bill for the half you never saw.
The 92.35% base
The 15.3% isn’t charged on your full profit. Self-employment tax is calculated on 92.35% of your net self-employment earnings. The 7.65% that’s carved out mirrors the employer-share deduction an ordinary business would take, so a business owner isn’t taxed on money that would otherwise have been a deductible expense.
In practice, if your net profit is $50,000, the tax applies to about $46,175 of it. It’s a modest adjustment, but it matters when you estimate what you owe — using the full profit overstates the bill.
The deductible half
There’s a second piece of relief. You can deduct one half of your self-employment tax when figuring your income tax. This isn’t a deduction against the self-employment tax itself — it reduces the income on which your regular income tax is calculated.
- The deduction restores parity with employees, whose employer-paid half was never counted as their taxable income.
- It lowers your income tax, not your self-employment tax, so both taxes still need to be planned for.
Between the 92.35% base and the deductible half, the effective sting is a bit smaller than a flat 15.3% on every dollar — but it’s still real money that has to be reserved.
Quarterly estimated taxes
Employees have taxes withheld automatically; freelancers don’t, so the tax system expects you to pay as you earn through quarterly estimated payments. Miss them and you can face underpayment penalties even if you pay in full at year-end. A common habit is to set aside a fixed share of every payment received — covering both income tax and the 15.3% — so the quarterly due dates never require scrambling.
Canada handles the same idea differently. There’s no self-employment tax by that name; instead, self-employed workers pay both the employee and employer portions of CPP contributions on their net business income, and those with a balance owing above a threshold make quarterly instalment payments much like U.S. estimated taxes.
- Estimate your annual profit and reserve for tax as you go.
- Pay quarterly rather than waiting for one large bill, to avoid penalties.
- Remember both taxes: income tax and the self-employment or CPP piece.