Self-Employment Tax Calculator: How to Estimate What You Owe and Set Money Aside

Self-employment tax is the Social Security and Medicare tax you pay on your own business profit, and it is 15.3% of 92.35% of your net earnings, which works out to about 14.1% of net profit up to the Social Security wage base. On $60,000 of net profit, the self-employment tax is about $8,478. It is separate from federal income tax, and most self-employed people pay both through quarterly estimated payments. This guide shows the calculation step by step, explains the deduction for half of the tax and covers how to avoid underpayment penalties.

Who pays self-employment tax

You generally owe it if you work for yourself and have net earnings from self-employment of $400 or more in a year. That includes sole proprietors, independent contractors who receive Form 1099-NEC, and partners in a partnership. An S corporation owner who takes wages is treated differently, and an LLC taxed as a sole proprietorship or partnership is generally subject to self-employment tax on its profits. A single-member LLC is a "disregarded entity" for income tax by default unless it elects corporate taxation.

When you are an employee, your employer pays half of Social Security and Medicare tax and withholds the other half from your pay. When you are self-employed you pay both halves.

The rates

• Social Security: 12.4% on net earnings up to the annual Social Security wage base, which the Social Security Administration sets each year.
• Medicare: 2.9% on all net earnings, with no cap.
• Additional Medicare Tax: an extra 0.9% on earnings above $200,000 for single filers, $250,000 for married filing jointly and $125,000 for married filing separately.
• The combined base rate is 15.3%, applied to 92.35% of net profit. The 92.35% factor mirrors the fact that an employer's half of the tax is deductible to the employer.

Step-by-step calculation

1. Calculate net profit from your business: revenue minus allowable business expenses (Schedule C for sole proprietors).
2. Multiply by 0.9235 to get net earnings subject to self-employment tax.
3. Apply 15.3% (12.4% up to the wage base plus 2.9%).
4. Deduct half of the self-employment tax when you calculate your adjusted gross income. This is an adjustment on Schedule 1 and does not reduce the self-employment tax itself.
5. Calculate income tax on the remaining income after your standard or itemized deduction and any qualified business income deduction, if eligible.

Worked example (illustrative)

A freelancer has $60,000 of net profit.

• Net earnings for SE tax: $60,000 x 0.9235 = $55,410
• Self-employment tax: $55,410 x 15.3% = $8,477.73
• Deductible half: $8,477.73 / 2 = $4,238.87
• Income adjusted for the deduction: $60,000 - $4,238.87 = $55,761.13, before the standard deduction and any other items

Income tax depends on filing status, other income, deductions and credits, so this guide does not state a single figure. The freelancer can use IRS Form 1040-ES worksheets or the IRS Tax Withholding Estimator for the rest.

How much should you set aside?

Many self-employed people set aside a percentage of every payment in a separate savings account. A common planning range is 25% to 30% of net profit for combined federal taxes at moderate incomes, but that is a rule of thumb, not a rule. Your number may be lower with large deductions or higher with other income, high earnings or state income tax. Calculate the actual figure at least once and compare it to your rule.

The table assumes net profit stays under the Social Security wage base, so check the current base on the Social Security Administration website for higher earners.

Quarterly estimated taxes

Because no one withholds tax from your self-employment income, the IRS expects payments during the year, using Form 1040-ES. The standard due dates are:

• April 15 for income earned January through March
• June 15 for April and May
• September 15 for June through August
• January 15 of the following year for September through December

When a date falls on a weekend or legal holiday, the deadline moves to the next business day. State estimated taxes may have different dates. You generally need to make estimated payments if you expect to owe $1,000 or more in federal tax after withholding and credits.

Safe harbor rules

You can avoid an underpayment penalty by paying at least the smaller of:

• 90% of the tax shown on this year's return, or
• 100% of the tax shown on last year's return (110% if last year's adjusted gross income was more than $150,000, or $75,000 if married filing separately).

Last year's tax is a handy target when income is rising or irregular. Penalty rules and exceptions are on Form 2210 and its instructions. If your income is uneven, the annualized income installment method may reduce penalties.

Ways to reduce the burden legally

• Track every deductible expense. Each dollar of deduction reduces both income tax and self-employment tax.
• Retirement contributions: a SEP IRA, Solo 401(k) or SIMPLE IRA reduces income tax, though not self-employment tax.
• Health insurance deduction: self-employed health insurance premiums can be deductible within limits.
• Home office deduction if you meet the exclusive and regular use rules.
• Qualified business income deduction (Section 199A): many pass-through owners can deduct a portion of qualified business income, subject to limits and rules that have been adjusted by recent legislation. Check IRS guidance for the current treatment.
• Entity choice: some owners consider an S corporation election once profit is high enough, but that brings payroll, reasonable-compensation and filing requirements. Talk to a CPA before electing.

Common mistakes

• Treating the 15.3% as the whole tax bill and forgetting income tax.
• Skipping estimated payments and facing a large bill and penalty in April.
• Forgetting state estimated taxes or local taxes.
• Not separating tax money from operating cash.
• Applying the 15.3% rate to gross revenue rather than net profit.
• Missing deductions because of incomplete records.

When to consult a professional

If you have multiple income sources, a partnership, an S corporation election, large capital purchases or a prior-year balance due, a CPA or enrolled agent can calculate your quarterly payments more accurately than a simple estimate.

Frequently asked questions

Do I owe self-employment tax if I also have a W-2 job?

Yes, on net self-employment earnings of $400 or more. The Social Security wage base applies to your combined wages and self-employment earnings.

Does an LLC change this?

A single-member LLC is generally taxed like a sole proprietorship by default. Electing S corporation treatment changes how profit is taxed.

Can I pay my estimated tax late?

You can, but penalties and interest may apply for each underpaid installment. Paying something is better than paying nothing.

Is self-employment tax deductible?

Half of it is deductible when you calculate adjusted gross income, which lowers income tax but not the SE tax itself.

Sources

• Internal Revenue Service — Self-Employment Tax, Schedule SE, Form 1040-ES and Publication 505
• Social Security Administration — current wage base and contribution rates
• Related: employee cost guide and hourly rate guide