What the 0.9235 factor actually does
Schedule SE reduces your Schedule C profit by 7.65% before applying the 15.3% rate. This adjustment compensates for the fact that W-2 employees don't pay FICA on the portion of compensation their employer pays for them. Without it, self-employed people would pay slightly more than the equivalent W-2 employer + employee combined.
Why the Social Security cap matters
Once your combined W-2 wages + net SE earnings cross the Social Security wage base (~$168k in 2025, scheduled to rise to roughly $176k in 2026), additional dollars only pay the 2.9% Medicare rate (plus 0.9% Additional Medicare above the AGI threshold). That's why high-income freelancers often see their effective SE tax rate drop sharply past $170k — the marginal SE rate falls from 15.3% to 3.8%.
Self-employment tax is the line item that turns 'I made $80k freelancing' into 'why is my refund negative $11,000?' The 15.3% rate sounds simple, but the actual calculation includes a 92.35% net-earnings adjustment, a Social Security wage base cap, a 0.9% Additional Medicare Tax above $200k, and a deduction for half the SE tax. This calculator handles all four so the number you get matches what TurboTax produces.
What each input means
Get these inputs right and the output is reliable. Get them wrong and the calculator just multiplies bad assumptions.
Net self-employment income
Schedule C profit — gross revenue minus all business deductions.
Typical range: $30k–$150k for solos; $150k–$500k for staffed agencies or specialists.
Other W-2 wages (if any)
Wages from a day job already subject to FICA. Reduces Social Security portion of SE tax against the wage base cap.
Typical range: $0 for full-time freelancers; $50k–$200k for side-hustlers.
Filing status
Affects the Additional Medicare Tax threshold ($200k single, $250k MFJ).
Typical range: Most solos: single or MFJ.
Worked examples
Real scenarios with the math walked through line by line.
Full-time freelancer, $90k net
Scenario: $90k Schedule C profit, no other wages, single filer.
Math: Net earnings = $90k × 0.9235 = $83,115. SS portion = $83,115 × 0.124 = $10,306. Medicare = $83,115 × 0.029 = $2,410. Total SE tax = $12,716. Deductible half = $6,358.
Outcome: $12.7k owed for SE tax alone, on top of regular income tax. The $6,358 deduction is your one consolation.
Side-hustler, $40k freelance + $150k W-2
Scenario: $40k Schedule C, $150k W-2 wages already FICA'd, single filer.
Math: Net earnings = $40k × 0.9235 = $36,940. SS wage base remaining = $168,600 − $150,000 = $18,600. SS portion = min($36,940, $18,600) × 0.124 = $2,306. Medicare = $36,940 × 0.029 = $1,071. Total SE tax = $3,377.
Outcome: Lower SE tax because your W-2 already used most of the SS wage base. This is a real planning lever for high earners.
Common mistakes
Where this calculation usually goes wrong in the real world.
- Forgetting the 92.35% adjustment. SE tax is on net earnings × 0.9235, not net profit directly. Skipping this overstates the bill by ~$1k on $50k net.
- Ignoring the SS wage base cap ($168,600 for 2026). High W-2 earners with side hustles often owe far less SE tax than they think.
- Missing the half-SE-tax deduction. You get to deduct 50% of SE tax from income on the 1040 — worth $2k–$5k for typical freelancers.
- Not planning for Additional Medicare Tax. Above $200k single / $250k MFJ, an extra 0.9% kicks in. Self-employed pay this themselves; W-2 employers usually withhold it.
- Confusing SE tax with income tax. They're separate. You can owe SE tax even when your income tax is zero.
When to use this calculator
- Calculating your true freelance bill before April 15.
- Sizing quarterly estimated payments accurately.
- Deciding whether S-corp election would meaningfully cut your SE tax bill.
- Modeling a side hustle on top of a W-2 to find the marginal tax rate.
- Comparing freelance offers against W-2 alternatives apples-to-apples.
Glossary
FICA
Federal Insurance Contributions Act — the payroll tax that funds Social Security and Medicare. 7.65% paid by W-2 employee + 7.65% by employer.
Net earnings from self-employment
Schedule C net profit × 92.35%. The adjustment exists because SE tax is meant to mirror the FICA paid on top of W-2 wages.
Social Security wage base
Annual income cap on the 12.4% Social Security portion. $168,600 for 2026. Medicare's 2.9% has no cap.
Additional Medicare Tax
Extra 0.9% Medicare tax on combined wages + SE income above $200k single / $250k MFJ. Not deductible.
Schedule SE
IRS form where SE tax is calculated. Output flows to Schedule 2 of your 1040.
More questions answered
Can I avoid SE tax with an LLC?
Not with a default LLC — single-member LLCs are disregarded entities, taxed exactly like sole proprietors. To reduce SE tax, you'd elect S-corp status (Form 2553), pay yourself a 'reasonable' W-2 salary, and take the rest as distributions not subject to SE tax. Savings usually start meaningfully above ~$80–100k net income — see the LLC vs S-corp calculator.
Do I pay SE tax on every dollar of side-hustle income?
Only if your total SE income for the year is $400+. Below that threshold there's no SE tax owed (you may still owe income tax). Above $400, the full amount is subject to SE tax, calculated at 15.3% of 92.35% of net earnings.
Why is SE tax higher than the FICA my W-2 friends pay?
Because they're only paying their half (7.65%). Their employer pays the other 7.65% on top of their salary — money the employer could otherwise pay them. As a freelancer, you're effectively the employer too, so you pay both halves. The half-SE-tax deduction is the IRS's partial acknowledgment that this is structurally unfair.
Methodology last reviewed: 2026-05 by the RevenueLab editorial team.
FAQ
Is self-employment tax the same as income tax?
No — SE tax is the 1099 equivalent of FICA (Social Security + Medicare) and is paid in addition to federal and state income tax. The 15.3% is on top of your federal/state bracket, not instead of it.
Do I owe SE tax if my side-hustle made under $400?
No. The IRS exempts net self-employment earnings under $400/year from SE tax. You still need to report the income for income tax, but no Schedule SE.
Can I avoid SE tax with an S-corp?
Partially. With an S-corp election, you pay yourself a reasonable salary (FICA applies just like W-2) but the remaining profit comes out as distributions, which are NOT subject to SE tax. See our LLC vs S-corp calculator for the crossover analysis.
What's the Additional Medicare Tax?
0.9% extra Medicare tax on earned income over $200k single / $250k MFJ / $125k MFS. It applies to wages, self-employment income, and railroad retirement compensation combined — not investment income (that's the NIIT, 3.8%, separate).