Quarterly estimated tax calculator for 2026
Put in your profit and see what to pay the IRS on each of the four 2026 dates: the least that avoids a penalty, what clears the year, and how far behind you are if a date has gone by.
Your 2026 figures
The four dates
How quarterly estimated tax is worked out
Nobody withholds tax from self-employment income, so the IRS expects it in four instalments during the year instead of in one payment in April. The instalment has to cover two taxes: income tax on the profit, and self-employment tax, which is the Social Security and Medicare an employer and employee would otherwise split. The second is the one people forget, and on a modest profit it is often the larger of the two.
On $100,000 of profit, single, with no other income: self-employment tax is 15.3% of 92.35% of the profit, $14,129.55. Half of that comes off income, the standard deduction of $16,100 comes off, and the 20% qualified business income deduction comes off, leaving $61,468.18 taxable and $8,235.00 of income tax. The year's tax is $22,364.55, or $5,591.14 a quarter to owe nothing in April.
You do not have to pay all of it during the year to avoid a penalty. The IRS asks for the smaller of 90% of this year's tax and 100% of last year's (110% if last year's adjusted gross income was over $150,000), counting any withholding. That is the lower figure above, and when last year's tax is lower than this year's it is the better target: it is fixed on the day you file last year's return and does not move when this year goes well.
If you missed a quarter
Pay what was due now. The penalty works like interest: it is figured at the IRS underpayment rate on each instalment, from its own due date until it is paid. Paying the shortfall today stops it growing, and the remaining instalments go back to their normal size. Put this year's payments made so far in the box above and the calculator shows how far behind you are and what to pay on each date still to come.
Withholding is treated as paid in equal parts on the four dates, whenever it was actually taken. So a person with a job as well as a side business can catch up late in the year by raising the withholding on their pay, and it counts as if it had been paid on time.
The 2026 figures used here
| Figure | 2026 | Source |
|---|---|---|
| Due dates | Apr 15, Jun 15, Sep 15, Jan 15, 2027 | 2026 Form 1040-ES |
| Standard deduction: single or separate, joint, head of household | $16,100, $32,200, $24,150 | 2026 Form 1040-ES, Rev. Proc. 2025-32 |
| Added at 65 or older, per person: unmarried, married | $2,050, $1,650 | Rev. Proc. 2025-32 |
| Deduction for seniors, per person, less 6% of AGI over $75,000 ($150,000 joint) | $6,000 | IRS |
| Earnings that carry the 12.4% Social Security tax | $184,500 | 2026 Form 1040-ES |
| Qualified business income deduction in full up to | $201,750; $403,500 joint | Rev. Proc. 2025-32 |
| Additional Medicare Tax of 0.9% above | $200,000; $250,000 joint; $125,000 separate | IRS Topic 560 |
| No estimated tax needed if you will owe less than | $1,000 | 2026 Form 1040-ES |
This is arithmetic, not tax advice. It follows the 1040-ES worksheet for one person or couple with a sole proprietorship, the standard deduction and ordinary income. It leaves out capital gains rates, itemised deductions, credits other than the amount you type, state tax, and the qualified business income deduction above the threshold, where it depends on the wages the business pays and on what kind of business it is. Leaving that out can only make the tax shown higher, not lower. Social Security wages are taken to equal the wages you type.