How estimated taxes work
When you have a job, your employer withholds tax from every paycheck and sends it to the IRS for you. When you're self-employed, nobody does that — so the IRS asks you to pay as you go, in four estimated installments across the year. If you expect to owe $1,000 or more after withholding, you're generally on the hook for these payments.
For self-employment income, each payment has to cover two taxes: self-employment tax (about 15.3% for Social Security and Medicare, on 92.35% of your net profit) and federal income tax on what's left after the deductions you're entitled to. This calculator estimates both, applies a simplified qualified business income (QBI) deduction and the standard deduction for your filing status, and divides the total into four to show a per-quarter number.
The calculator uses the 2026 federal figures: the 2026 standard deduction and brackets, and the $184,500 Social Security wage base.
2026 estimated tax due dates
The four payment periods aren't equal quarters. Here's the schedule for the 2026 tax year:
| Payment | Covers income earned | Due date |
|---|---|---|
| 1st | January 1 – March 31, 2026 | April 15, 2026 |
| 2nd | April 1 – May 31, 2026 | June 15, 2026 |
| 3rd | June 1 – August 31, 2026 | September 15, 2026 |
| 4th | September 1 – December 31, 2026 | January 15, 2027 |
The next one is January 15, 2027. You can skip it if you file your 2026 return and pay the full balance by February 1, 2027 (January 31 falls on a Sunday). For the 2027 tax year, the first three payments are due April 15, June 15 and September 15, 2027.
How much to set aside: 2026 examples
These are the calculator's own results at 2026 rates, for someone with no other income who takes the standard deduction. The share is the rough percentage of profit to move into a tax savings account as money comes in.
| Annual profit | Single, per quarter | Single, share | Married jointly, per quarter | Married, share |
|---|---|---|---|---|
| $40,000 | $1,760 | 18% | $1,413 | 14% |
| $60,000 | $2,913 | 19% | $2,430 | 16% |
| $80,000 | $4,065 | 20% | $3,520 | 18% |
| $100,000 | $5,414 | 22% | $4,673 | 19% |
| $150,000 | $9,225 | 25% | $7,554 | 20% |
| $200,000 | $13,164 | 26% | $10,822 | 22% |
Two things stand out. Self-employment tax alone is about 14% of profit at every level in the table, so even a small profit owes something. And the share rises as profit grows, because income tax brackets climb while self-employment tax doesn't.
The simplest habit: each time a deposit lands, move that share to a separate savings account and pay the quarterly bill from there. With your books reconciled every month, you're working from your real profit to date instead of a guess.
The safe-harbor shortcut
If projecting your income feels like guesswork, there's a simpler way to stay penalty-free: the safe-harbor rule. Pay at least 100% of last year's total tax across your four payments — or 110% if your prior-year adjusted gross income was over $150,000 — and the IRS won't charge an underpayment penalty, even if you end up owing more at filing. Many owners use safe harbor for predictability and simply true up the balance when they file. This calculator uses the projected-income method instead, which is more precise when your income is steady; check both and pay the one that fits your situation.
Uneven income? Pay as you earn it
Four equal payments assume income arrives evenly. If your business is seasonal, or a big job lands late in the year, the annualized income installment method lets each payment match the income you actually earned in that period. You work it out on Schedule AI of Form 2210 and file it with your return. It needs your income for each period, which a reconciled monthly P&L gives you.
If your business is an S-corp
This calculator models a sole proprietor or single-member LLC, where all profit is subject to self-employment tax. In an S-corp, your salary runs through payroll with income tax withheld, and the rest of the profit reaches your personal return without self-employment tax. You may still owe estimated payments on that profit. One rule worth knowing: the IRS treats withholding as paid evenly through the year, no matter when it was withheld, so raising your withholding late in the year can cover earlier quarters, which a late estimated payment can't. More in S-corp vs LLC and the S-corp savings calculator.
How to pay
- IRS Direct Pay: free, straight from a checking or savings account, no sign-up. Choose Estimated Tax as the reason, Form 1040-ES, and the right tax year.
- Your IRS Online Account: make a payment and see every estimated payment you've already made, which helps at filing time.
- Debit card, credit card or digital wallet: through an IRS-approved payment processor, which charges a fee.
Keep each confirmation number. In the books of a sole proprietor or single-member LLC, a federal estimated payment is an owner draw, not a business expense, because it's personal income tax.
What this calculator doesn't include
To keep it simple, this is a federal-only estimate. It does not include your state or local estimated taxes (many states require their own, and so do some cities, like Ohio's municipal income tax), tax credits (child tax credit, education credits, and others), retirement or health-insurance deductions, the 0.9% additional Medicare tax, or the income limits and phase-outs on the QBI deduction. Any of those can move your real payment up or down. Treat the number as a starting point, and confirm your actual quarterly amount with a qualified CPA or tax pro — something that's far easier when your books are current every month.
Related reading: our full guide to quarterly estimated taxes, the tax season prep checklist, S-Corp vs LLC, and our S-Corp savings calculator, or the whole system in our complete guide to small business bookkeeping.