This self employment tax calculator estimates what a freelancer, contractor or single-owner business will owe on 1099 income for 2026: self-employment tax, federal income tax, New Jersey income tax, and the amount to set aside each quarter. It is meant for people paid without withholding who need a number before the next estimated payment is due.
How to use the calculator
- Net self-employment profit (1099 income minus expenses): your business income for the year after business expenses.
- Filing status: single, married filing jointly, head of household or married filing separately.
- W-2 wages (you and spouse, if any): salary from a job, which affects the Social Security cap and your tax bracket.
- Tax already withheld from W-2 pay: appears once you enter wages; it is subtracted from the year’s total.
- State income tax: choose New Jersey resident, or leave state tax out.
How it is calculated
- Self-employment tax. Net earnings are 92.35% of profit. Social Security is 12.4% of net earnings up to the $184,500 wage base minus your W-2 wages; Medicare is 2.9% of all of it. Nothing is due under $400 of net earnings. Above $200,000 ($250,000 married filing jointly, $125,000 separately) the 0.9% Additional Medicare Tax is added. Sources: SSA wage base, IRS Topic 751, Additional Medicare Tax Q&A.
- Adjusted gross income = profit + wages − half of self-employment tax.
- Standard deduction for 2026: $16,100 single or married filing separately, $32,200 married filing jointly, $24,150 head of household (Rev. Proc. 2025-32).
- QBI deduction: 20% of business profit after the self-employment tax deduction, limited to 20% of taxable income. Above $201,750 of taxable income ($403,500 joint) it phases out over $75,000 ($150,000 joint), as it would for a business with no employees (IRS QBI deduction).
- Federal income tax from the 2026 brackets: 10%, 12%, 22%, 24%, 32%, 35% and 37%.
- New Jersey income tax on profit plus wages, less the $1,000 personal exemption ($2,000 for a joint return), using the rate tables in the 2026 NJ-1040-ES. New Jersey does not allow the deduction for half of self-employment tax, so the base is larger than the federal one.
- Left to pay = total tax − withholding. Per quarter = that amount ÷ 4.
Worked example with the default inputs
Single filer, New Jersey resident, $85,000 of profit, no W-2 wages:
| Line | Amount |
|---|---|
| Net earnings ($85,000 × 92.35%) | $78,497.50 |
| Self-employment tax (15.3%) | $12,010.12 |
| Adjusted gross income ($85,000 − $6,005.06) | $78,994.94 |
| After the $16,100 standard deduction | $62,894.94 |
| QBI deduction (capped at 20% of taxable income) | $12,578.99 |
| Taxable income | $50,316 |
| Federal income tax | $5,789.91 |
| New Jersey income tax (on $84,000) | $3,224.55 |
| Total tax for the year | $21,024.58 (24.73% of income) |
| Set aside per quarter | $5,256 |
Leave New Jersey out and the total drops to $17,800.03, or $4,450 a quarter.
What this calculator leaves out
- Credits such as the child tax credit, and itemized deductions.
- Other income: interest, dividends, capital gains, rental income.
- Above-the-line deductions such as retirement plan contributions and self-employed health insurance, which can lower income tax noticeably.
- Other states. If you live in New York or work across state lines, the state figure will be different.
- Payments already made. Estimated payments you have sent this year are not an input; subtract them yourself.
- Uneven income. The quarterly figure assumes you split the year’s tax into four equal parts.
Quarterly estimated taxes: due dates and safe harbor
Self-employed people usually pay tax four times a year on Form 1040-ES. For 2026 the due dates are April 15, June 15 and September 15, 2026, and January 15, 2027 (Form 1040-ES).
You generally have to make estimated payments if you expect to owe at least $1,000 after withholding. To stay clear of the underpayment penalty, pay at least the smaller of:
| Safe harbor | Amount |
|---|---|
| This year’s tax | 90% |
| Last year’s tax | 100% |
| Last year’s tax, prior-year AGI over $150,000 ($75,000 if married filing separately) | 110% |
The calculator’s quarterly number covers 100% of this year’s estimated tax, which is more than the 90% minimum. If your income is rising fast, paying 100% or 110% of last year’s tax can be smaller and still protect you from the penalty, with the rest due at filing.
Turning the estimate into a plan
A calculator gives you a starting number. Our tax planning work sets quarterly payments from your real books and adjusts them as the year moves, and our individual tax preparation covers the return itself, including Schedule C and Schedule SE. If you work for yourself, the page for freelancers and individuals explains how we help through the year. For other numbers, see all our free calculators. When you want someone to check your estimate, book a free 15 to 30 minute consultation.