Self-Employment Tax Calculator
Calculate your 1099 self-employment tax with the full Schedule SE order, wage-base coordination, Additional Medicare handling, and deductible half shown step by step.
Built from IRC sections, Schedule SE instructions, Form 8959 instructions, and the SSA wage-base release.
Self-employment tax
2026$0
on $0 of net SE earnings
W-2 wage coordination Only needed if you also have a W-2 job
Enter only your own Social Security wages (box 3). Your spouse's wages don't reduce your cap.
Enter your Medicare wages (box 5). For married filing jointly, enter combined spouse Medicare wages.
Only needed if you also have W-2 wages. Social Security wages coordinate the wage-base cap; Medicare wages coordinate the Additional Medicare threshold.
Schedule SE walkthrough
| Line | Description | Amount |
|---|
How your SE tax is built up
This is an estimate, not tax advice. It computes federal self-employment tax for planning. Your filed return can differ based on optional methods, special income types, and state rules. Confirm anything material with a CPA or enrolled agent.
The basics
What self-employment tax is
Self-employment tax is the Social Security and Medicare tax you pay on net business earnings when you work for yourself. It uses the same core rates as payroll tax, but the calculation flow is different from W-2 withholding. SE tax is the same in every state; your state income tax is a separate layer calculated on your taxable income.
SECA (Self-Employment Contributions Act)
The federal law (IRC §1401) that imposes Social Security and Medicare tax on self-employment income. It's the self-employed equivalent of FICA, the payroll tax that employers and employees split.
Schedule SE
The IRS form (Form 1040 Schedule SE) where you calculate your self-employment tax. It walks through the 92.35% multiplier, the Social Security wage base, and the deductible half, line by line.
Net earnings from self-employment
Your net business profit (Schedule C line 31, or the combined profit of all your self-employment activities) multiplied by 92.35%. This is the base the 15.3% SE tax rate applies to.
Social Security wage base
The annual cap on earnings subject to the 12.4% Social Security portion. For 2026 it's $184,500, set by the Social Security Administration. The cap is shared across your W-2 wages and self-employment earnings combined.
Additional Medicare Tax
A 0.9% surtax on combined wages and net self-employment earnings above a filing-status threshold: $200,000 for single, $250,000 for married filing jointly, $125,000 for married filing separately. The thresholds are fixed by statute and don't adjust for inflation.
Above-the-line deduction
A deduction you take on Schedule 1 to reduce your adjusted gross income, whether you itemize or take the standard deduction. The deductible half of self-employment tax is an above-the-line deduction.
The 92.35% multiplier
The factor the IRS applies to your net business profit to get your net earnings from self-employment. It equals 1 minus half of the 15.3% SE tax rate (1 - 0.0765 = 0.9235), approximating the employer half of the tax that a W-2 employee wouldn't pay.
FICA vs. SECA
FICA is the payroll tax (Social Security plus Medicare) that employers and employees split 7.65% each. SECA is the self-employed equivalent, where you pay both halves - the full 15.3% - because you're both the employer and the employee.
Form 8959
The IRS form where you calculate the 0.9% Additional Medicare Tax. It's separate from Schedule SE - the Additional Medicare Tax is reported on Schedule 2, not on Schedule SE's line 12 total.
The math
The formula, and the order it runs in
Self-employment tax is calculated in a fixed order: first the 92.35% adjustment, then Social Security and Medicare, then Additional Medicare if it applies.
SE tax = (Net profit x 92.35% x 12.4% up to wage base) + (Net profit x 92.35% x 2.9%) + Additional Medicare
Net SE earnings (x92.35%)
Multiply your net profit by 92.35% to get net earnings from self-employment.
Wage base remaining
Subtract W-2 Social Security wages from the annual Social Security wage base.
SS portion (12.4%)
Apply 12.4% to net SE earnings up to the remaining wage base only.
Medicare portion (2.9%)
Apply 2.9% to all net SE earnings (no cap).
SE tax subtotal
Add Social Security and Medicare portions from steps 3 and 4.
Additional Medicare (0.9%)
Apply 0.9% to net SE earnings above the reduced filing-status threshold.
SE tax total
Add the subtotal and Additional Medicare Tax.
Deductible half (50%)
Deduct 50% of the subtotal only (excluding Additional Medicare Tax).
The Social Security wage base
The 12.4% Social Security portion applies only up to the annual wage base. For 2026 that base is $184,500, and it is shared across W-2 wages and self-employment earnings combined.
If your W-2 wages already use all or most of the wage base, your self-employment Social Security portion can drop sharply or fall to zero. The calculator coordinates this automatically when you enter W-2 wages in the Advanced panel.
$184,500
2026 Social Security wage base
Set by the SSA. The 2025 base was $176,100. Only the 12.4% SS portion is capped — the 2.9% Medicare portion has no limit.
Additional Medicare Tax
Additional Medicare Tax is a 0.9% surtax above fixed filing-status thresholds. The thresholds are set by statute and don't adjust for inflation.
The calculator reduces your threshold by W-2 Medicare wages first, then applies 0.9% only to net self-employment earnings above the reduced threshold. This matches the Form 8959 Part II line-by-line mechanics.
Filing-status thresholds
Fixed by statute — not inflation-adjusted. Reported on Form 8959, not Schedule SE.
The deductible half
You can deduct 50% of the Social Security and regular Medicare portions as an above-the-line adjustment on Schedule 1, line 15. This reduces your adjusted gross income, whether you itemize or take the standard deduction.
The 0.9% Additional Medicare Tax is not part of that deduction, so the calculator shows it separately to avoid overestimating your adjustment.
The Qualified Business Income deduction (Section 199A) lowers your income tax, not your self-employment tax. The deductible half shown here does reduce the income base that QBI is calculated on, so the two interact indirectly.
What the 50% deduction covers
50%
of the included portion, deductible on Schedule 1, line 15
Worked examples
How it plays out at different income levels
The same SE tax rules can produce very different outcomes depending on profit level, W-2 wages, and filing status.
$60,000 of net self-employment profit in 2026, single filer, no W-2 wages.
- Net SE earnings (92.35%)$55,410.00
- SE tax total$8,477.73
- Deductible half$4,238.87
$250,000 of net self-employment profit in 2026, single filer, no W-2 wages.
- Social Security portion (capped)$22,878.00
- Additional Medicare$277.88
- SE tax total$29,851.25
$80,000 net self-employment profit with $150,000 of W-2 Social Security and Medicare wages, single filer.
- Remaining wage base$34,500
- Additional Medicare$214.92
- SE tax total$6,635.44
$300 net self-employment profit in 2026, single filer.
- Net SE earnings$277.05
- Below $400 thresholdYes
- SE tax total$0.00
The form
How the result flows to your tax return
Your self-employment tax shows up on your return in two places: the tax itself adds to what you owe, and the deductible half reduces your adjusted gross income. Here's how three scenarios map to the actual lines on the forms.
Straightforward case
$60k profit, no W-2$60,000 net SE profit, single filer, no W-2 wages. SE tax total: $8,477.73.
Below the $200,000 Additional Medicare Tax threshold, so Form 8959 is not required.
| Form line | What goes there | Amount |
|---|---|---|
| Schedule SE, Line 4a/4c | Net earnings (× 92.35%) | $55,410.00 |
| Schedule SE, Line 10 | Social Security portion (12.4% × $55,410) | $6,870.84 |
| Schedule SE, Line 11 | Medicare portion (2.9% × $55,410) | $1,606.89 |
| Schedule SE, Line 12 → Schedule 2, Line 4 | SE tax | $8,477.73 |
| Schedule SE, Line 13 → Schedule 1, Line 15 | Deductible half | $4,238.87 |
→ Form 1040, Line 23 (via Schedule 2): $8,477.73
High earner, Additional Medicare
$250k profit, no W-2$250,000 net SE profit, single filer, no W-2 wages. SE tax total: $29,851.25 (includes Additional Medicare Tax).
The Social Security portion is capped at the $184,500 wage base. Additional Medicare Tax applies because net earnings exceed $200,000.
| Form line | What goes there | Amount |
|---|---|---|
| Schedule SE, Line 4a/4c | Net earnings (× 92.35%) | $230,875.00 |
| Schedule SE, Line 10 | Social Security portion (12.4% × $184,500 cap) | $22,878.00 |
| Schedule SE, Line 11 | Medicare portion (2.9% × $230,875) | $6,695.38 |
| Schedule SE, Line 12 → Schedule 2, Line 4 | SE tax | $29,573.38 |
| Schedule SE, Line 13 → Schedule 1, Line 15 | Deductible half | $14,786.69 |
| Form 8959, Line 13 → Schedule 2, Line 11 | Additional Medicare Tax (0.9% × $30,875) | $277.88 |
→ Form 1040, Line 23 (via Schedule 2, lines 4 + 11): $29,851.25
Side business with a W-2 job
$80k profit + $150k W-2$80,000 net SE profit, single filer, $150,000 W-2 Social Security and Medicare wages. SE tax total: $6,635.44.
W-2 wages reduce both the Social Security wage-base room and the Additional Medicare Tax threshold (reduced from $200,000 to $50,000).
| Form line | What goes there | Amount |
|---|---|---|
| Schedule SE, Line 4a/4c | Net earnings (× 92.35%) | $73,880.00 |
| Schedule SE, Line 9 | Remaining wage-base room ($184,500 − $150,000) | $34,500.00 |
| Schedule SE, Line 10 | Social Security portion (12.4% × $34,500) | $4,278.00 |
| Schedule SE, Line 11 | Medicare portion (2.9% × $73,880) | $2,142.52 |
| Schedule SE, Line 12 → Schedule 2, Line 4 | SE tax | $6,420.52 |
| Schedule SE, Line 13 → Schedule 1, Line 15 | Deductible half | $3,210.26 |
| Form 8959, Line 13 → Schedule 2, Line 11 | Additional Medicare Tax (0.9% × $23,880) | $214.92 |
→ Form 1040, Line 23 (via Schedule 2, lines 4 + 11): $6,635.44
Sole proprietors only. This mapping is for Schedule C filers. Partnerships and S-corps pass self-employment income through separately on K-1s, and the form flow differs. If you file as anything other than a sole proprietor or single-member LLC, confirm the form flow with a CPA or enrolled agent. The calculator shows cent-precision figures for planning; your actual filed forms round to whole dollars, so expect small differences.
Watch out
Common mistakes to avoid
- Applying 15.3% to gross revenue instead of net business profit after expenses.
- Forgetting the 92.35% multiplier before applying the 12.4% and 2.9% rates.
- Not coordinating W-2 wages with the wage base which can overstate the Social Security portion.
- Missing the deductible half that reduces adjusted gross income on Schedule 1.
- Confusing SE tax with income tax since both apply but are calculated differently.
- Ignoring the Additional Medicare Tax when income crosses the filing-status threshold.
When to bring in a pro. Talk to a CPA or enrolled agent if you use optional Schedule SE methods, have church employee income, received partnership self-employment allocations, or need filing-level reconciliation across multiple income sources. If your net profit is climbing past roughly $75,000 to $80,000, an S-corp election may reduce your SE tax by splitting salary from distributions — that's a separate decision our LLC vs S-Corp calculator (planned) will walk through.
Behind the answer
How I tested the self-employment tax calculator
Before this calculator went live, I validated every major calculation path against 63 test cases derived from Schedule SE, Form 8959, Form 1040 instructions, and SSA wage-base releases. Here's what that covers.
Order of operations
I tested the full Schedule SE formula — the 92.35% multiplier, the Social Security wage-base cap, the 2.9% Medicare portion, and the deductible half — across scenarios covering single and MFJ filers, with and without W-2 wages.
Edge cases
The $400 filing threshold, negative profit (floored at zero), wage-base exhaustion, and W-2 wages exceeding the wage base are all tested. I also regression-tested a specific calculation step that previously produced rounding errors.
Year-specific figures
The 2026 Social Security wage base ($184,500) is checked against the SSA's official announcement, and the 2025 wage base ($176,100) against the printed Schedule SE. Both are confirmed current.
Bad inputs
Non-numeric profit, negative W-2 wages, invalid filing status, and out-of-range tax years are all caught and surfaced as field-level errors before the calculation runs.
Every test case traces back to the IRC section, Schedule SE line, or SSA figure it came from. You can download all 63 test cases as JSON and check any calculation against the cited source. If you spot a result that doesn't match, tell me and I'll fix it.
FAQ
Questions people ask
How much is self-employment tax?
Self-employment tax is 15.3% of your net earnings from self-employment: 12.4% for Social Security (up to the 2026 wage base of $184,500) and 2.9% for Medicare (no cap). The 15.3% applies after multiplying your net profit by 92.35%, not to your full Schedule C profit.
What is the 2026 Social Security wage base?
The 2026 Social Security wage base is $184,500, set by the Social Security Administration. Only the first $184,500 of your combined wages and net self-employment earnings is subject to the 12.4% Social Security portion. Earnings above the cap are subject only to the 2.9% Medicare portion.
How do I calculate my self-employment tax?
Multiply your net self-employment profit by 92.35% to get your net earnings from self-employment, then apply 12.4% for Social Security (up to the wage base) and 2.9% for Medicare (no cap). The calculator above runs this in the same order as Schedule SE and shows each step.
What is the deductible half of self-employment tax?
You can deduct 50% of your self-employment tax - the 12.4% Social Security plus 2.9% Medicare portions, but not the 0.9% additional Medicare tax - as an above-the-line adjustment on Schedule 1, line 15. This reduces your adjusted gross income, not the SE tax itself.
Do I owe self-employment tax if I also have a W-2 job?
Yes, but your W-2 wages and self-employment earnings share the same Social Security wage base. If your W-2 wages already reached the $184,500 cap for 2026, only the 2.9% Medicare portion applies to your self-employment income. Enter your W-2 Social Security wages in the Advanced panel and the calculator coordinates the cap automatically.
What happens if my net earnings are under $400?
You owe no self-employment tax if your net earnings from self-employment are less than $400 for the year, though you may still owe federal income tax on the income. The $400 threshold applies after the 92.35% multiplier, so roughly $433 of net Schedule C profit still falls under it.
Is self-employment tax the same as income tax?
No. Self-employment tax is the Social Security and Medicare tax on your net business earnings (15.3%), separate from federal income tax, which is calculated on your total taxable income using progressive brackets. You owe both, and quarterly estimated payments cover both together.
How much should I set aside for taxes on 1099 income?
A common rule of thumb is 25–30% of your net 1099 income to cover both self-employment tax and federal income tax, but your actual number depends on your income level, filing status, deductions, and state. This calculator gives you the precise self-employment tax portion; add your estimated income tax on top for your full set-aside target.
What this calculator doesn't model (and why)
Farm vs. nonfarm income
Schedule SE routes farm profit (Schedule F) through line 1a and nonfarm (Schedule C) through line 2, but the regular-method math is identical. The calculator doesn't model the farm/nonfarm optional methods, which can let you pay SE tax on a smaller base.
Church employee income
Schedule SE lines 5a/5b handle church employee income separately, with a lower $100 floor and a $108.28 filing threshold. Not modeled here.
Statutory employees
Income from statutory-employee work (reported on Schedule C) is excluded from SE tax because FICA is withheld by the payer. If you enter it here, the calculator will overstate your SE tax.
Foreign earned income
The foreign earned income exclusion (Form 2555) does NOT reduce self-employment tax. SE tax applies to the full foreign self-employment profit. Enter your pre-exclusion profit, not post-exclusion.
Ministers and religious exemptions
Ministers, members of religious orders, and certain religious sect members have special SE tax rules (Form 4361/4029 exemptions). Not modeled here.
Whole-dollar rounding
IRS forms are completed in whole dollars. The calculator shows cent-precision figures for planning; your actual filed Schedule SE will round to the nearest dollar.
Updates
What's changed
- Expanded the page with more on how the result flows to your tax return, what this calculator doesn't cover, and where the numbers come from.
- Confirmed the 2026 Social Security wage base ($184,500) against the latest SSA figures.
Sources
Where the numbers come from
- IRC §1401: Self-employment tax (SECA rates)
- IRC §1402: Net earnings from self-employment (92.35% multiplier, wage base, $400 threshold)
- IRC §164(f): Deduction for one-half of self-employment tax
- Schedule SE (Form 1040): line-by-line structure for Parts I-V
- Instructions for Schedule SE (Form 1040) (2025)
- Instructions for Form 8959: Additional Medicare Tax (2025)
- Form 1040 Instructions: Schedule 1 line 15 and Schedule 2 lines 4/11/21
- SSA Cost-of-Living Increase and Other Determinations for 2026, 90 Fed. Reg. 49047 (Nov. 3, 2025)