US Quarterly Estimated Tax Calculator (2025)

Worked example

Example: single freelancer, $90,000 net Schedule C profit, no other income, no withholding, 2024 total tax $12,000, 2024 AGI $80,000.

1. SE tax: $90,000 × 0.9235 = $83,115 net earnings. All below the $176,100 wage base, so SE tax = $83,115 × 15.3% = $12,717.
2. Half-SE deduction: $12,717 ÷ 2 = $6,358.
3. AGI: $90,000 − $6,358 = $83,642.
4. Taxable income: $83,642 − $15,750 standard deduction = $67,892.
5. Income tax (2025 single): 10% × $11,925 = $1,192.50; 12% × $36,550 = $4,386; 22% × $19,417 = $4,271.74. Total = $9,850.
6. Total projected tax: $9,850 + $12,717 = $22,567.
7. Safe harbor: 90% of current year = $20,310; prior-year 100% = $12,000 (AGI under $150,000, so 100% not 110%). Take the smaller = $12,000.
8. Quarterly payment: $12,000 − $0 withholding = $12,000 ÷ 4 = $3,000 per quarter.

Paying $3,000 each quarter meets the safe harbor and avoids the underpayment penalty, though about $10,567 will still be due when the return is filed. To avoid that April bill, base payments on the current-year $22,567 figure instead (roughly $5,642 per quarter).

Why this differs from a simple income tax estimate

Quarterly estimated tax is not just income tax split into four. For the self-employed it bundles two separate taxes into every payment: ordinary income tax and self-employment (SE) tax, the 15.3% that replaces the Social Security and Medicare withholding an employer would normally handle. SE tax alone can be the larger of the two for middle-income sole proprietors, and it is easy to forget because there is no paycheck deducting it.

The calculator also models the deduction for one-half of SE tax, which lowers your AGI before income tax is applied, so the two taxes interact. A generic tax estimator that ignores SE tax will understate what a freelancer owes by thousands of dollars. That is exactly the gap that produces surprise April bills and underpayment penalties.

The safe harbor: how to avoid a penalty

The IRS charges an underpayment penalty (effectively interest) if you do not prepay enough during the year. You are protected if, through withholding and estimates, you pay the smaller of 90% of this year's total tax or 100% of last year's total tax. If your prior-year AGI was over $150,000 ($75,000 if married filing separately), the prior-year figure rises to 110%.

The prior-year route is powerful because it is a fixed, known number: if your 2024 total tax was $12,000 and 2024 AGI was under $150,000, paying $12,000 across 2025 blocks the penalty no matter how much your income grows. The trade-off is a possible balance due at filing. The 90%-of-current-year route minimizes that balance but requires forecasting income you may not know yet. The calculator shows both so you can choose.

Note that estimates must be roughly even across quarters. The cumulative safe-harbor bar is 22.5%, 45%, 67.5% and 90% by each deadline, so skipping Q1 and catching up in Q4 can still trigger a penalty for the early quarters.

2025 due dates and how payments are timed

The four 2025 installments are due April 15, 2025, June 16, 2025 (June 15 is a Sunday), September 15, 2025, and January 15, 2026. The periods are uneven: Q1 covers three months, Q2 only two, Q3 three, and Q4 four, which is why the June deadline sneaks up on people.

Withholding is treated as paid evenly across the year regardless of when it was actually withheld, but estimated payments count when you actually pay them. If your income is lumpy (a big Q3 contract, for instance), the annualized income installment method on Form 2210 can reduce early-quarter penalties by matching payments to when income was earned. You can pay online free via IRS Direct Pay or EFTPS, or mail a Form 1040-ES voucher.

Who needs to pay and who can skip it

You must make estimated payments if you expect to owe at least $1,000 after subtracting withholding and refundable credits, and your withholding is less than the safe-harbor amount. If you owe under $1,000 at filing, no estimates are required and no penalty applies.

Two common ways to avoid quarterly vouchers entirely: if you also have a W-2 job, you can increase withholding on Form W-4 to cover the self-employment shortfall, since withholding counts as timely no matter when it happens. And if you had no tax liability in the prior year and were a US citizen or resident for the whole 12-month year, you are exempt from the estimated-tax penalty for the current year. High-income filers should still watch the 110% prior-year rule, and anyone crossing $200,000 in wages plus SE earnings ($250,000 MFJ) should add the 0.9% Additional Medicare Tax to their projection.

Frequently asked questions