Self-Employed Tax Calculator 2025 — SE Tax, Federal & QBI

How self-employment tax actually works in 2025

When you’re a W-2 employee, you pay 7.65% FICA (6.2% Social Security + 1.45% Medicare) and your employer quietly matches it with another 7.65%. The moment you go self-employed, you’re on the hook for both halves — that’s the 15.3% self-employment tax. The IRS softens the blow in two ways: SE tax only applies to 92.35% of your net earnings, and you can deduct half the SE tax above-the-line when calculating your income tax.

The 2025 numbers you actually need

• Social Security wage base: $176,100. You pay the 12.4% portion only on earnings up to this cap.
• Medicare: 2.9% on every dollar of SE income — no cap.
• Additional Medicare: Another 0.9% on SE income above $200,000 (single) / $250,000 (MFJ).
• Standard deduction: $15,750 (single, 2025).
• QBI deduction: Up to 20% of qualified business income. Phase-in starts at $197,300 single / $394,600 MFJ.
• SEP-IRA cap: Lesser of 25% of net SE earnings or $70,000.

Why quarterly estimated payments matter

Unlike a W-2 employee, no one is quietly withholding tax from your 1099 income. The IRS expects you to pay as you earn — which means writing four checks a year (April 15, June 16, September 15, January 15). Miss a quarter and you can rack up underpayment penalties even if you square the full bill by April 15. The well-worn shortcut: pay 100% of last year’s liability (110% if your AGI cleared $150k) in four equal installments — that’s the “safe harbor” and it puts the penalty risk to bed.

The retirement-account superpower most freelancers underuse

Here’s a perk of being self-employed that nobody talks about enough: the SEP-IRA and solo 401(k). At the $70,000 maximum (for those earning enough), you can shelter dramatically more than the $23,500 a W-2 employee can put in a regular 401(k). Every dollar contributed cuts both your federal income tax and your SE-tax-adjusted base, and grows tax-deferred until retirement. Most self-employed people don’t set one up until year three — and miss tens of thousands in lifetime tax shelter as a result.

Estimates for the 2025 US tax year, single filer only. State and local taxes, AMT, Net Investment Income Tax, SSTB QBI restrictions, and high-income QBI phase-outs are not modelled. This isn’t tax advice — talk to a CPA before you file or fund a retirement account.

Sources: IRS – Self-employment tax, SSA – Contribution and Benefit Base, IRS – Topic 560 Additional Medicare Tax, IRS – QBI deduction, IRS – 2025 inflation adjustments, IRS – SEP-IRA.