Self-Employment Tax Calculator Tools Compared
Typing "self employment tax calculator app" into Google usually means one thing: you want a fast, reliable answer to "how much will I owe?" — not a full bookkeeping system, just a number you can trust. This guide compares the calculator tools worth using for that specific job, and shows you the math behind them so you can sanity-check any result.
If you're looking for something that tracks your income continuously and adjusts your estimate throughout the year, that's a different category — see our guide to AI tools for quarterly estimated taxes instead. The tools below are for a single, one-time estimate.
How self-employment tax actually works (2026 figures)
Self-employment (SE) tax is separate from income tax. It funds Social Security and Medicare — the same two things a traditional employer and employee would split — but since you're both, you pay the full combined rate.
For 2026:
| Component | Rate | Applies To |
|---|---|---|
| Social Security | 12.4% | First $184,500 of net earnings, which is 92.35% of your net profit (max $22,878) |
| Medicare | 2.9% | All net self-employment income — no cap |
| Additional Medicare surtax (reported separately on Form 8959) | 0.9% | Only income above $200,000 (single) / $250,000 (married filing jointly) |
Figures reflect 2026 SSA/IRS thresholds. Confirm current rates at ssa.gov before filing.
Two adjustments every accurate calculator should apply:
- You're only taxed on 92.35% of your net earnings, not the full amount — this mirrors how an employer's half of payroll tax is not counted as the employee's income.
- Half of your total SE tax is deductible on your income tax return.
A calculator that skips either of those two steps will overstate what you owe. Worth knowing before you trust any single tool's number.
Self-employment tax applies once your net self-employment earnings reach $400 or more. If you also earn W-2 wages, the $184,500 Social Security limit is shared between your wages and your self-employment earnings. Check the details in the IRS self-employment tax guide.
We ran the same numbers through each calculator
On September 25, 2026 we entered the same figures into each calculator: $60,000 of net self-employment profit, single filer, no other income, Texas. We compared each result with the manual worksheet calculation of $8,477.73 (shown in the example below). Calculators ask for slightly different inputs, so we note below where we had to make a choice.
| Tool | SE tax shown | Difference from manual ($8,477.73) | State tax shown? | What we noticed |
|---|---|---|---|---|
| 1-800Accountant | $8,477.73 | None (exact match) | No, self-employment tax only | Asks for year-to-date self-employment and W-2 income. Shows one total, to the cent. |
| NerdWallet | $8,478 | $0.27 (rounded to the dollar) | No, self-employment tax only | Lets you pick tax year 2026 or 2027. Breaks the result into Social Security, Medicare, taxable earnings and the deductible half. |
| TurboTax Self-Employed Tax Calculator | Could not run | Not tested | Not tested | The calculator did not work for us. |
| Bonsai Tax | Could not run | Not tested | Not tested | The form did not load for us. |
The four calculators we looked at
These are four free tools that estimate self-employment tax. We ran two of them ourselves and describe the other two from their own pages. Self-employment tax is the Social Security and Medicare tax that freelancers pay on their net profit. None of these tools replaces the IRS Schedule SE or a tax professional.
| Tool | What it asks | What it shows | Did we run it? |
|---|---|---|---|
| NerdWallet | Tax year (2026 or 2027), filing status, self-employment income | Total self-employment tax with a breakdown: Social Security, Medicare, taxable earnings and the deductible half | Yes |
| 1-800Accountant | Year-to-date self-employment income and W-2 income | One estimated self-employment tax figure | Yes |
| TurboTax Self-Employed Tax Calculator | Not tested | Not tested | No, it did not run for us |
| Bonsai Tax | State and filing status (per its state pages) | Not tested | No, the form did not load for us |
NerdWallet Self-Employment Tax Calculator
Open the calculator (on NerdWallet's self-employment tax guide). We ran it on September 25, 2026.
- What it asks: the tax year (2026 or 2027), your filing status (single or head of household, married filing jointly, or married filing separately) and your self-employment income, which it defines as gross self-employment income minus business expenses.
- What it shows: your total self-employment tax and roughly what share of your income it is, plus a breakdown into Social Security tax, Medicare tax, taxable self-employment earnings (92.35% of your income) and the deductible half of the tax.
- Our test: with $60,000 of self-employment income, single filer and tax year 2026, it showed $8,478, made up of $6,871 Social Security and $1,607 Medicare on $55,410 of taxable earnings, with $4,239 as the deductible half. That matches our manual calculation of $8,477.73, rounded to the dollar.
- Limits: NerdWallet says the tool is for estimating self-employment tax only. It does not calculate regular income tax on your self-employed earnings, and it does not account for tax withheld from W-2 earnings or for farm or church employment income. It points to the IRS for details on the Additional Medicare Tax. The form we used had no field for W-2 wages.
- Good for: understanding where the number comes from, because every step is shown.
1-800Accountant Self-Employment Tax Calculator
Open the calculator. We ran it September 25, 2026.
- What it asks: your year-to-date self-employment income (net profit from your business or freelance work) and your year-to-date W-2 income, with the instruction to enter 0 if it does not apply.
- What it shows: a single estimated self-employment tax figure, labelled as a year-to-date estimate, with a "Talk to a tax expert" button beside it.
- Our test: with $60,000 of self-employment income and no W-2 income, it showed $8,477.73, an exact match with our manual calculation.
- Things to know: the page calls the result a directional estimate. It says the tool helps with your state and federal self-employment tax burden, but in our test the result was one self-employment tax figure (Social Security and Medicare) with no separate state amount. The site also offers a free quarterly estimated tax calculator, which we did not test. The company sells accounting and tax services, so expect prompts to speak to one of its advisers.
- Good for: freelancers who also have a W-2 job, because it asks for both kinds of income.
TurboTax Self-Employed Tax Calculator
Open the calculator. We could not get it to run on September 25, 2026, so we have not tested its results.
- What TurboTax says: its tax tools page lists a Self-Employed Tax Calculator, described as a way to estimate your self-employment tax and avoid surprises. TurboTax lists it among its free calculators, next to a self-employed tax deductions calculator.
- Do not confuse it with TaxCaster. TaxCaster is a different TurboTax tool. It estimates a federal income tax refund or the amount you may owe, and it does not calculate state taxes. It is not built for self-employment tax.
- Worth knowing: TurboTax is Intuit's tax filing software, and the calculators sit alongside its paid filing products.
Bonsai Tax self-employment tax calculators
The Texas page. The form did not load for us on September 25, 2026, so we have not tested its results.
- What Bonsai says: Bonsai publishes a separate self-employment tax calculator page for each of many states, including Texas, California, Florida, New York and Illinois. The pages ask for your state and tax filing status. Bonsai describes Bonsai Tax as a product built for self-employed workers to track expenses, maximise write-offs and estimate quarterly taxes.
- A note on states: self-employment tax is a federal tax, so we would not expect the state you pick to change that figure. We could not confirm what the state choice does.
- Check the year: the pages we saw are labelled 2025, and at least one state page still quotes an older year's Social Security limit in its text. Check the year on the page before relying on any figure.
The manual option: IRS Form 1040-ES worksheet
The IRS's own Form 1040-ES includes the worksheet every calculator above is ultimately approximating. It's slower, but it's the ground truth if two tools disagree and you want to know which one is right.
Which one should you use?
For a plain $60,000 of self-employment profit, the two calculators we could run gave the same answer as the IRS worksheet method, within rounding. So for the basic question of how much self-employment tax you owe, accuracy was not the difference. The differences are in what each tool asks and shows.
- Use NerdWallet's calculator if you want to see where the number comes from. It splits the total into Social Security and Medicare, shows the 92.35% taxable earnings and the deductible half, and lets you pick tax year 2026 or 2027. It rounds to the dollar and has no field for W-2 wages.
- Use 1-800Accountant's calculator if you also earn W-2 wages, because it has a W-2 income field. It shows one total to the cent and is built around year-to-date figures. Expect a prompt to talk to one of its tax experts.
- Neither calculates your regular income tax or state tax. They show self-employment tax only, so you still need to estimate income tax separately.
- If two tools disagree, work the IRS Form 1040-ES worksheet by hand.
We could not run TurboTax's Self-Employed Tax Calculator or Bonsai Tax's calculator, so we cannot say how their results compare.
FAQ
Is self-employment tax the same as income tax?
No. SE tax (15.3%) funds Social Security and Medicare specifically. You still owe separate federal — and likely state — income tax on top of it, calculated using your regular tax bracket.
Why do different calculators give me different numbers?
The most common causes are rounding, whether the tool applies the 92.35% adjustment, which tax year's Social Security limit it uses, and whether it shows only self-employment tax or mixes in income tax. In our test, the two calculators we ran matched the IRS worksheet within rounding. If the gap is large, check your inputs against the IRS worksheet.
Do I need an app for this, or can I calculate it by hand?
You can calculate it manually using Form 1040-ES. Most people use a calculator because manual estimates go stale as income changes through the year — but the manual version is the one to trust if you want to verify a tool's math.
Does a one-time calculator replace an ongoing tracking app?
No — a calculator gives you a snapshot for today. A tracking app updates your estimate automatically as new income and expenses come in, which matters more the further you get from your last calculation.
Read next
- Top AI Tax Tools for Estimated Quarterly Payments (Freelancers in USA): how to turn your self-employment tax estimate into quarterly payments.
- How US Freelancers Can Use AI to Track Deductible Expenses: lower net profit means lower self-employment tax.
- How to Adjust Your W-4 Withholding to Cover 1099 Side Income Taxes: for freelancers who also have a W-2 job.
- Best AI Bookkeeping Software for LLC Owners: keep your net profit figure accurate through the year.
S. Hossain writes AI Fin Insights, independent guides to AI finance tools for freelancers in the US, UK, Germany and the EU.]
This guide is for information only and is not tax advice. Rates and rules change, so check the date above and confirm details with the official source or a qualified accountant.