Quarterly Estimated Tax Calculator (2026)

Who has to pay estimated tax

If you expect to owe at least $1,000 in federal tax for the year after any withholding, the IRS expects you to pre-pay it in four installments rather than all at once in April. Most freelancers, contractors, and business owners without a W-2 fall into this.

If you also hold a W-2 job, you can often skip quarterly payments by increasing withholding there instead — withholding is treated as paid evenly across the year, which can patch an earlier shortfall.

The four 2026 due dates

The payments are due four times, and the periods they cover are uneven. A payment is on time if it's postmarked or submitted by the due date; if a date lands on a weekend or holiday, it shifts to the next business day.

How much to pay each quarter

The simplest approach is to take your projected total tax for the year and divide by four. If your income is uneven, you can instead pay based on what you've actually earned each period (the annualized method), though that's more work.

Either way, you only need to hit the safe harbor to avoid a penalty: the smaller of 90% of this year's tax or 100% of last year's (110% if your prior-year AGI topped $150,000). Enter last year's tax above and the tool sizes each payment to that floor.

The underpayment penalty

Miss the safe harbor and the IRS charges an underpayment penalty, calculated on Form 2210 as interest on the shortfall from each due date until you pay. It's not a flat fine — it accrues by the day at the federal short-term rate plus a few points, so paying late is better than not paying, and paying something beats paying nothing.

How to actually pay

Pay online for free through IRS Direct Pay (from a bank account) or the Electronic Federal Tax Payment System (EFTPS). You can also mail a check with a Form 1040-ES voucher. Whichever you use, label the payment for the correct tax year and quarter so it's credited properly.

Keep a record of each confirmation number — it's your proof the payment was on time if a penalty notice ever shows up.

What this estimate does and doesn't cover

Quarterly calculates 2026 federal income tax and self-employment tax for a sole proprietor or single-member LLC, applies the standard deduction and a simplified 20% QBI deduction, and sizes your four estimated payments. It is a planning estimate, not tax advice.

It does not include state or local income tax, the full QBI wage-and-property limitation that applies to higher earners, the qualified-business-income phase-outs for specified service businesses, itemized deductions, tax credits (child tax credit, premium tax credit, retirement-saver credits), the net investment income tax, or business deductions beyond the half-of-SE-tax adjustment. For anything with real money on the line, confirm with a CPA or enrolled agent.