Estimated tax payment calculator
TL;DR: You avoid the federal underpayment penalty if withholding plus estimated payments cover the smaller of 90% of your 2026 tax or 100% of your 2025 tax (110% if 2025 AGI was over $150,000), or if you owe less than $1,000 at filing. This calculator finds that safe harbor, subtracts withholding and payments so far, and splits the rest across your remaining 2026 due dates: April 15, June 15, September 15 and January 15, 2027.
Educational only, not tax, legal, or investment advice. Examples are illustrations, not predictions. Rules and limits change; verify current figures and talk to a qualified professional about your situation.
The IRS runs a pay-as-you-go system, and if you have self-employment income, rentals, big capital gains or retirement withdrawals without withholding, "go" means quarterly estimated payments. Miss them and you pay an underpayment penalty, which works like interest. It isn't a disaster, but it's a completely avoidable fee, like an ATM charge at your own bank.
The good news: you don't need to predict your exact tax. You only need to hit a safe harbor. Rules are from IRS Publication 505, as of October 2026. Full walk-through: the estimated tax payments guide.
CPA Warning Label: The penalty is computed quarter by quarter. Paying everything in January fixes the total but not earlier quarters, unless the money comes through withholding, which is treated as paid evenly through the year.
How to use it
- Projected 2026 tax: your total tax including self-employment tax, after credits. Last year's return adjusted for changes is a fine starting point, or use the marginal tax rate calculator.
- Withholding: federal tax withheld from wages, pensions, Social Security and IRA withdrawals for the whole year, including expected future paychecks.
- Payments made: 2026 estimates already sent, plus any 2025 overpayment applied to 2026.
- 2025 tax and AGI: from your 2025 Form 1040. AGI over $150,000 ($75,000 married filing separately) means the prior-year safe harbor is 110%. (The tool applies the $150,000 test; adjust if you file separately.)
- Payments left: how many 2026 due dates remain.
The safe harbor rules
| Test | Requirement |
|---|---|
| Current year | Pay 90% of 2026 tax |
| Prior year | Pay 100% of 2025 tax (110% if 2025 AGI over $150,000) |
| Small balance | Owe less than $1,000 after withholding and credits |
Pay the smaller of the first two, and you're penalty-free even if you owe a lot more at filing. The prior-year test is the easy one when income is rising, because you already know the number. Farmers and fishermen have special rules. If your prior year was less than a full year, or you had no tax liability, other rules apply.
Illustration
Sam left a W-2 job and started consulting in 2026. 2025 tax: $15,000 on $120,000 of AGI. He expects 2026 tax of $20,000 (including self-employment tax), with $8,000 withheld from his final paychecks.
Safe harbor: the smaller of $18,000 (90% of 2026) or $15,000 (100% of 2025) is $15,000. Withholding covers $8,000, so he needs $7,000 more: four payments of $1,750. In April 2027 he'll owe another $5,000, but no penalty. If his 2025 AGI had been $200,000, the prior-year test becomes $16,500, and each payment rises to $2,125.
Who usually needs estimates
- Self-employed and gig workers: no employer withholds, and self-employment tax adds 15.3% on most net earnings.
- Landlords with positive taxable rental income.
- Investors with large realized gains, dividends or interest, especially in a year with a big sale.
- Early retirees living on taxable accounts, Roth conversions or IRA withdrawals with no withholding.
- Two-earner couples whose withholding is set as if each were the only earner.
The penalty itself works like interest on the shortfall for each quarter, at a rate the IRS sets quarterly based on the federal short-term rate plus three points. It's not huge, but there's no reason to pay it when the prior-year safe harbor is sitting right on last year's return.
Tips that cut the hassle
- Withholding beats estimates: withholding is treated as paid evenly, so a late-year W-4 change or IRA withholding can cover earlier quarters.
- Annualized method: if income is lumpy (a big December gain), Form 2210 Schedule AI can lower early-quarter requirements.
- Pay online: IRS Direct Pay or your IRS online account, and save the confirmation.
- Recheck midyear: after a big sale or a slow quarter, rerun the calculator and adjust the remaining payments up or down.
- States too: most income tax states have their own estimated payment rules.
Early retirees: see estimated taxes for early retirees. Landlords: rental property estimated taxes. More tools on the calculators page.
FAQ
When are 2026 estimated tax payments due?
April 15, June 15 and September 15, 2026, and January 15, 2027. Dates shift to the next business day if they fall on a weekend or holiday.
What is the 110% rule?
If your prior-year AGI was over $150,000 ($75,000 if married filing separately), the prior-year safe harbor is 110% of last year's tax instead of 100%.
Do I need estimated payments if I owe less than $1,000?
No. If you will owe less than $1,000 after withholding and credits, there is no underpayment penalty.
Can I make one big payment instead of four?
You can, but the penalty is figured by quarter, so a late lump sum leaves earlier quarters short. Extra withholding avoids that because it counts as paid evenly through the year.
Sources & fact-check notes
- IRS Publication 505: Tax withholding and estimated tax (accessed 2026-10-27)
- IRS Topic 306: Penalty for underpayment of estimated tax (accessed 2026-10-27)
Figures checked October 27, 2026. Rules and limits change; verify with the official source before acting.