Why self-employed workers pay more in payroll tax, not less
A W-2 employee and their employer split Social Security and Medicare tax 50/50 — 7.65% each, 15.3% total. When you’re self-employed, there’s no employer to split it with, so you pay the full 15.3% yourself. This is called self-employment tax, and it’s calculated separately from your income tax — it’s not a bracket, it’s a flat rate applied to 92.35% of your net self-employment earnings (a small adjustment that roughly mirrors how an employer’s share isn’t taxed as the employee’s income).
Why estimated payments exist at all
The tax system is pay-as-you-go — the IRS expects tax paid throughout the year, not in one lump sum the following April. W-2 employees satisfy this automatically through paycheck withholding. Without an employer withholding on your behalf, the IRS requires you to estimate and pay quarterly instead, and if you underpay by enough, you can owe a penalty on top of the tax itself — even if you pay the full balance by the April filing deadline.
The deduction most new freelancers miss
Half of your self-employment tax is deductible from your federal taxable income — not from the tax itself, but from the income the income tax is calculated on. This exists because the “employer half” of payroll tax was never meant to be taxed as your personal income in the first place; the deduction approximates that treatment for the self-employed. This calculator applies that deduction automatically, but it’s easy to miss if you’re estimating by hand.
What “net” actually means here
This calculator asks for net self-employment income — revenue minus your legitimate business expenses — not your gross revenue. Underestimating your deductible expenses inflates your estimated tax; overestimating them risks underpayment. If you’re new to self-employment, track expenses carefully from day one rather than guessing at tax time, since the gap between gross and net is often the single biggest driver of your actual tax bill.
Using this calculator
Estimate your net income for the full year as accurately as you can — if your income is irregular, the IRS allows you to adjust each quarter’s payment based on income earned so far rather than locking in one number for all four. The four due dates are fixed by the IRS regardless of your specific income pattern: April 15, June 15, September 15, and January 15 of the following year.
This article is for educational purposes only and isn't legal, financial, or tax advice. See our Disclaimer for details.
