Self-Employment Tax

Self-employment (SE) tax is the self-employed version of FICA. It funds Social Security (12.4% on net earnings up to the annual wage base, $168,600 in 2024) and Medicare (2.9% on all net earnings, plus an Additional Medicare Tax of 0.9% on earnings above $200,000 single / $250,000 married). The combined base SE rate is 15.3% on the first $168,600 of net earnings.

An employee splits FICA with their employer — the worker pays 7.65%, the employer pays 7.65%. A self-employed person pays both halves, which is why the SE rate is double what shows on a W-2. The IRS lets you deduct half of SE tax (the 'employer portion') from your gross income on the front page of Form 1040, partially offsetting the sting.

SE tax applies to net earnings, not gross revenue. Subtract legitimate business expenses (Schedule C deductions) before applying the 15.3%. There's also a small adjustment — you multiply net earnings by 0.9235 before the SE rate — that approximates the deduction an employer would get for paying the employer half of FICA.

The US tax system is pay-as-you-go. W-2 employees have tax withheld every paycheck; self-employed people are expected to make four estimated payments per year, due roughly April 15, June 15, September 15, and January 15. Miss them and the IRS charges an underpayment penalty (currently around 8% annualized on the shortfall).

Safe-harbor rule: you avoid the penalty if you've paid in (through withholding, estimated payments, or both) at least 100% of last year's total tax liability — or 110% if last year's AGI was over $150,000. This is the simplest target for self-employed earners with steady income: divide last year's total federal tax by four and pay that each quarter.

If your income jumped significantly, the safe-harbor target may be much lower than what you'll actually owe. You can use the safe-harbor amount to dodge the penalty, but reserve the difference in cash so you're not caught short on April 15.

A reasonable rule of thumb for a single 1099 earner with net income between $50k and $150k: set aside 28–32% of every payment in a separate account dedicated only to taxes. This covers federal income tax (12–24% effective), SE tax (~14% after the half-deduction), and a small buffer for state tax in states without their own income tax buffer.

If you're in a state with income tax (CA, NY, OR, MN, etc.), add 5–10% on top. If you're in a no-income-tax state (TX, FL, WA, NV, TN, NH, SD, WY, AK), the federal-only number is enough.

Hold the reserve in a high-yield savings account, not in your operating checking. The yield won't make you rich, but it removes the temptation to spend money that already belongs to the IRS. On the quarterly due dates, transfer from the reserve account to the IRS via EFTPS or Direct Pay — both are free.

Start with $80,000 of 1099 revenue and $8,000 of legitimate business expenses (Schedule C). Net profit: $72,000. Multiply by 0.9235 to get net earnings from self-employment: $66,492.

Self-employment tax is 15.3% (the full Social Security + Medicare combination, since you're well under the $168,600 SS wage base): $66,492 × 0.153 = about $10,173. Half of that ($5,086) is deductible from gross income before federal income tax.

Federal taxable income: $72,000 − $5,086 (half SE tax) − $14,600 (standard deduction, single) = $52,314. Federal income tax on $52,314 in 2024 single brackets: roughly $6,300.

State tax at 5% applied to the same $52,314: about $2,616. Total annual tax: $10,173 + $6,300 + $2,616 ≈ $19,089. Quarterly estimated payment: about $4,772. Take-home: roughly $52,911 — about 66% of gross.

Compare that to a W-2 employee on $80,000: their effective rate would land around 25–27% in the same state, so a 1099 contractor needs to gross about 7–10% more than the equivalent salary just to break even after the extra SE tax burden.