Self-Employment Tax Calculator

Self-employment tax is the Social Security and Medicare an employer would normally split with you — as a 1099 contractor you pay both halves. It is 15.3% on 92.35% of your net profit, and half of the result comes back as a deduction.

$0
self-employment tax for the year
Profit subject to it (92.35%)$0
Social Security portion (12.4%, up to the wage base)$0
Medicare portion (2.9%, plus 0.9% over $200,000 single)$0
Effective rate on profit—
Deducted back on Schedule 1 (half)$0

Your mileage deduction lowers this directly

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Self-employment tax is charged on profit, so every logged mile cuts it. RoadKept tracks them for you.

A worked example

A driver grosses $52,000 and deducts $20,794 of mileage plus $1,800 of other costs, leaving $29,406 of net profit.

92.35% of that is $27,156. At 15.3% the self-employment tax is about $4,155 — an effective 14.13% of profit. Roughly $2,077 of it is deducted back on Schedule 1, lowering the income their federal income tax is figured on.

Without the mileage deduction, profit would be $50,200 and the self-employment tax about $7,093. Those 28,000 logged miles saved $2,938 on this tax alone, before any income tax.

How this is calculated

Two steps that calculators routinely skip, each worth real money:

  1. Only 92.35% of profit is subject. The 7.65% removed represents the employer half an employee would not be taxed on. Applying 15.3% to the whole of your profit overstates the bill by about 8%.
  2. Half is deductible. Schedule 1 lets you deduct half of your self-employment tax, which lowers the income your federal income tax is calculated on. It does not reduce the self-employment tax itself.

The 15.3% is Social Security at 12.4% plus Medicare at 2.9%. Social Security stops at the contribution and benefit base — $184,500 for 2026 — so a high earner pays 12.4% up to that point and 2.9% on everything. Above $200,000 there is a further 0.9% Additional Medicare Tax, included in the Medicare line. That $200,000 is the threshold for a single filer, which is what this page assumes: it does not ask your filing status or your W-2 wages. The real threshold is $250,000 married filing jointly and $125,000 married filing separately, and it is measured on your combined wages and self-employment income — so if either applies to you, this figure will be off. Otherwise this calculator uses the same engine as the RoadKept app, so the two agree by construction rather than by coincidence.

The fastest way to lower it

Self-employment tax is charged on profit, not on what you were paid. Every deductible dollar reduces it at the full 14.13% effective rate — which is why an untracked mile is expensive twice: once on income tax, once here.

Questions drivers ask

How is self-employment tax calculated?

Net earnings from self-employment are generally 92.35% of your net profit. The regular tax on that is 12.4% Social Security plus 2.9% Medicare — both halves, because you pay the employee and the employer share. For 2026 the 12.4% applies only up to the $184,500 Social Security wage base, after taking any W-2 Social Security wages into account; Medicare has no cap. A separate 0.9% Additional Medicare Tax can apply once combined Medicare wages and self-employment income pass $250,000 married filing jointly, $125,000 married filing separately, or $200,000 otherwise. Special and optional Schedule SE rules can also apply.

Can I deduct any of it?

Yes. Schedule SE produces an adjustment to income for one-half of the regular self-employment tax, reported on Schedule 1. It reduces adjusted gross income and can reduce federal income tax, but it does not reduce the self-employment tax itself. Additional Medicare Tax is worked out separately on Form 8959 and is not part of that one-half deduction. This calculator shows the deductible figure.

Do I owe it on gross earnings?

No — on net earnings from self-employment, not gross receipts. Ordinary and necessary business deductions reduce your Schedule C profit before Schedule SE is calculated, and if you are eligible for and use the standard mileage method the mileage deduction is one of them. Note that the QBI deduction does not reduce the earnings self-employment tax is charged on.

When do I owe self-employment tax?

You generally must file Schedule SE and pay self-employment tax once your combined net earnings from self-employment reach $400 for the year. Special rules apply to certain church-employee income and to the optional methods for low earnings or a loss.

Our sources

Every figure on this page comes from an IRS primary source, checked on 31 July 2026:

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