Self-employment tax calculator for 2026

If you work for yourself, you pay both halves of Social Security and Medicare — 15.3% on most of your profit, on top of income tax. Here's what yours comes to, what to set aside each quarter, and whether an S corporation would cut it.

Checked against its sources September 21, 2026

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Illustrative product demo · fictional S corporation

The example continues by asking the owner for the receipt, checking for a duplicate reimbursement, and tracking a draft for review. No real action is taken. Enable JavaScript to step through it.

01 · A signal, not a conclusion

“Who is paying for the tools your team uses?”

The sample books show design work but no design-software expense this quarter. That could mean an owner paid personally—or simply that a transaction is missing.

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Before you reimburse yourself, close the evidence gap

Sample Planning Letter · fictional example · educational, not personalized advice

The free idea: check whether you pay business expenses personally. The useful next step is to turn that question into a reviewable expense report—not transfer money because a deduction sounds plausible.

Start with one month's records

Consider a fictional S-corporation owner who paid a $100 phone bill and an $80 internet bill personally. Assume their records support 60% business use of the phone and 50% of the internet. Those percentages are example assumptions, not IRS standard allowances or recommendations for your business.

Item	Example calculation	Candidate business amount
Phone	$100 × 60%	$60
Internet	$80 × 50%	$40
Total	$60 + $40	$100
Already reimbursed	Subtract the recorded payment	−$40
Left to review	$100 − $40	$60

That is $60 of potentially unreimbursed expenses, not $60 of tax savings. The plan, expenses, allocation, timing and prior payments still need checking. Do not project this month over a year without checking the other months.

Build the review packet

Find the itemized bills and evidence of who paid. Keep expense dates separate from the date you prepare the report.
Explain the business purpose and the evidence for each business-use share. Exclude personal use; don’t select a percentage just to reach a target.
Compare the bills with the business ledger and earlier expense reports. Mark the existing $40 reimbursement so it cannot be paid again.
Ask your accountant to check the reimbursement arrangement and timing. An accountable plan requires a business connection, timely substantiation and timely return of excess amounts. A document alone is not enough.
Prepare a draft report showing what is supported and what is still missing. Obtain the required review and approval before reimbursement. Preserve the approval and actual payment record with the packet.

The federal rules include a 60-day substantiation safe harbor, measured from when an expense is paid or incurred. It is not a universal rule that every older expense fails. Have your accountant assess the facts and the plan’s own terms; do not backdate records to fit a window.

A message you can adapt for your accountant

I’m reviewing personally paid business expenses for [period]. I’ve attached the bills, payment evidence, business-use explanation and previous reimbursements. Could you check whether our arrangement covers these costs, whether the timing and support are sufficient, and who should approve the report? The draft leaves [items] unresolved; no new reimbursement has been made.

Replace the brackets with real facts. Do not send documents through this website. The public reimbursement form can help organize a report; it cannot establish eligibility for you.

Decide the next action

If evidence is missing, assign a person and a follow-up date. If the accountant identifies a problem with the arrangement or timing, resolve it before payment. After an approved reimbursement, reconcile it and retain the evidence so next month’s check does not rediscover the same expense.

Sources checked September 23, 2026: IRS Publication 463, accountable plans and Treasury Regulation §1.62-2. This sample has not been sent as an issue. It does not include app access or a personal review of your records.

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How self-employment tax is worked out

Start from 92.35% of your net profit. That's your net earnings from self-employment — the 7.65% taken off stands in for the employer's half an employee never sees. If it's under $400, there's no self-employment tax.
Social Security: 12.4% of those earnings, up to $184,500 in 2026. W-2 wages from a job use up that limit first, so if you also have a salary, less of your self-employment income is taxed for Social Security.
Medicare: 2.9% of all of it, with no limit.
Additional Medicare: 0.9% on earnings above $200,000, or $250,000 on a joint return. Wages count toward that threshold first — on a joint return, both spouses' wages.

Half of the Social Security and Medicare parts is deductible when you work out your income tax, which lowers your income tax a little. It doesn't lower the self-employment tax itself.

Quarterly payments

No one withholds self-employment tax for you, so it's paid through estimated tax along with your income tax. For2026 the payments are due April 15, 2026, June 15, 2026, September 15, 2026 and January 15, 2027. The calculator's quarterly figure is the self-employment tax alone — set aside your income tax on top of it. The estimated tax calculator works out both, with the safe harbor.

Ways to lower it

Claim every legitimate business expense. Self-employment tax is on profit, so each deductible cost lowers it by about 14%, and your income tax too.
Consider an S corporation once profit is well above what you'd pay yourself. You'd pay payroll tax on a reasonable salary instead of self-employment tax on all the profit — but also payroll, a second return, and for many owners a smaller QBI deduction. The S corp calculator weighs all of it and tells you when it doesn't pay.

What doesn't lower it: contributing to a retirement plan or paying health insurance. Those reduce income tax, not self-employment tax. Whether any of this fits your situation is a question for your CPA or tax attorney.

Sources

IRC §1401 — the 12.4% and 2.9% rates, and the additional 0.9%
IRC §1402 — net earnings, the 92.35% rule, the $400 minimum, and wages against the wage base
SSA contribution and benefit base — $184,500 for 2026
Form 8959 instructions — the additional Medicare tax with both wages and self-employment income
IRC §164(f) — deducting half of self-employment tax
IRC §162(l)(4) — the health insurance deduction doesn't reduce self-employment earnings
Form 1040-ES — estimated tax and its 2026 due dates

General information, not advice for your situation. Whether a strategy fits depends on your facts — talk to your CPA or tax attorney about whether you qualify before you put it in place. Your accountant remains responsible for your return.

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Self-employment tax calculator for 2026

Your 2026 self-employment income

Your tax estimate is a starting point.

“Who is paying for the tools your team uses?”

“The fictional owner confirms a personal-card purchase.”

Ready for a follow-up—not a payment.

How self-employment tax is worked out

Quarterly payments

Ways to lower it

Sources

One strategy is a start. What else could fit?

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