Estimated Quarterly Tax Calculator (US)

IRS Estimated Quarterly Tax Payments

If you receive income that is not subject to withholding (freelance income, self-employment, rental income, dividends, or capital gains) you are generally required to make estimated tax payments four times per year. Missing or underpaying these can result in an IRS penalty.

2026 Payment Due Dates:

All four fall on a weekday in 2026, so none of them shift. The 15th moves to the next business day only when it lands on a weekend or a federal holiday, which is where the June 17 and September 16 dates you may remember from other years came from.

Notice the quarters are not quarters. Two months, then two, then three, then four. The June payment falls due two months after the April one rather than three, and that is the one people miss.

Safe Harbor Rules, how to avoid penalties:

You are safe from underpayment penalties if you pay the lesser of:

1. 90% of your current year’s total tax liability, OR
2. 100% of your prior year’s total tax liability (110% if prior year AGI > $150,000)

Meeting either condition means no penalty, even if you still owe at filing.

The prior-year route is usually the one to aim at, and not because it is smaller. It is a fixed number: you already know last year’s tax, so you can divide it by four in January and stop thinking about it. The 90% route moves every time your income does, which for a freelancer having a good year means the target keeps running away from you. Hit the prior-year figure and a surprise December windfall costs you nothing in penalties, only the balance at filing.

What to include in estimated payments:

• Federal income tax on all non-withheld income
• Self-employment tax on 92.35% of net SE income: 12.4% Social Security up to the $184,500 wage base for 2026, then nothing more, plus 2.9% Medicare on every dollar with no cap, plus 0.9% above $200,000 single or $250,000 married filing jointly
• Less any withholding from W-2 jobs or other sources

The wage base matters more than people expect at freelance-level incomes. A flat 15.3% on $300,000 of net earnings comes to $42,389. The correct Social Security and Medicare figure, with the 12.4% stopping at the wage base, is $30,912, and the 0.9% surcharge adds $693 on top for a single filer. That is an $11,477 gap against the flat-rate version, entirely down to a cap that a lot of quick calculators ignore.

Total Estimated Tax = Expected Tax Liability - Withholding

Quarterly Payment = Total Estimated Tax / 4

Tracking income through the year: Keep records of all income sources quarterly. If income varies significantly, you can use the annualized income installment method (IRS Schedule AI) to calculate each quarter separately and avoid overpaying early in the year.

State estimated taxes: Most states also require estimated payments if you owe more than $500–$1,000 in state tax. Check your state revenue agency for specific rules and due dates.

This page separates your W-2 withholding from your self-employment slice, which is what you want if you have both a salary and freelance income.
If all of your income is self-employment, the quarterly tax estimator asks for less and shows the taxable-income arithmetic step by step. The two agree to the cent on the same figures, including the wage base and the 110% safe harbor.