Quarterly Estimated Tax Calculator

Q: Who has to pay quarterly estimated taxes?

Generally, anyone who expects to owe at least $1,000 in federal tax for the year and doesn't have enough withheld through an employer — this typically includes freelancers, independent contractors, and self-employed business owners with no W-2 withholding.

Q: When are quarterly estimated tax payments due?

The IRS due dates are April 15, June 15, September 15, and January 15 of the following year — despite the name, the periods they cover aren't equal quarters (the second 'quarter' is only two months, for example).

Q: What happens if I underpay my quarterly estimated taxes?

The IRS can charge an underpayment penalty, calculated similarly to interest, on the shortfall for each period you underpaid — even if you pay the full amount owed by the April filing deadline. Paying close to evenly across all four due dates avoids this.

Q: Does this include state estimated taxes too?

No — this calculator covers federal self-employment tax and federal income tax only. Most states with an income tax also require their own separate quarterly estimated payments, which aren't included here.

Estimate what to send the IRS each quarter as a freelancer or self-employed worker — combining self-employment tax and federal income tax.

Written by the Calculator Index team · Source: IRS Form 1040-ES method (self-employment tax + federal brackets); IRS 2025 figures · Last reviewed September 2026

Estimated payment per quarter

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Self-employment tax (annual)

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Federal income tax (annual)

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Total estimated tax (annual)

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How quarterly estimated tax is calculated

Self-employment tax = Net income × 92.35% × 15.3% (up to the Social Security wage base, then 2.9% only)
Federal income tax = Federal brackets applied to (Net income − half of SE tax − standard deduction)
Quarterly payment = (SE tax + federal income tax) ÷ 4

Freelancers and the self-employed owe two federal taxes without any employer withholding to cover them: self-employment tax (the self-employed version of Social Security and Medicare, both halves) and regular federal income tax on the net profit. Because nothing is withheld throughout the year, the IRS requires paying both in four installments rather than waiting until the April filing deadline.

Worked example — $90,000 net self-employment income, single

SE-taxable base: $90,000 × 92.35% = $83,115. SE tax (15.3% combined, within the Social Security wage base): $12,717.

Federal taxable income: $90,000 − $6,358 (half of SE tax) − $15,000 standard deduction = $68,642. Federal tax on that: $10,015.

Total estimated tax: $12,717 + $10,015 = $22,732 → $5,683 per quarter.

The IRS's quarterly due dates aren't actually even quarters

Despite the name, the four due dates — April 15, June 15, September 15, and January 15 of the following year — don't split the year into four equal three-month periods. The second period covers only May and June (two months), while the fourth covers September through December (four months). This calculator divides the annual estimate evenly across four payments for simplicity, which is the most common approach, though you can adjust payments period-by-period if your income is uneven throughout the year.

Common mistakes when estimating quarterly taxes

Forgetting self-employment tax entirely. It's often larger than the federal income tax owed at moderate income levels, and it's easy to overlook if you're only thinking about "income tax."
Not deducting half of SE tax before calculating income tax. The IRS allows this above-the-line deduction, which lowers the federal income tax portion.
Ignoring state estimated tax obligations. Most states with an income tax require their own separate quarterly payments not covered by this calculator.

Frequently asked questions

Who has to pay quarterly estimated taxes?

Generally anyone expecting to owe at least $1,000 in federal tax without enough withholding — typically freelancers and the self-employed.

When are quarterly estimated tax payments due?

April 15, June 15, September 15, and January 15 of the following year — the periods aren't actually equal in length.

What happens if I underpay my quarterly estimated taxes?

The IRS can charge an underpayment penalty on the shortfall for each period, even if you pay the full amount by the April deadline.

Does this include state estimated taxes too?

No — this covers federal self-employment and income tax only; most states require their own separate estimated payments.

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Note: Simplified estimate using 2025 federal figures; excludes state estimated tax, credits, the additional Medicare tax on high earners, and Qualified Business Income deduction. Not tax advice. Last reviewed: September 2026.