When are quarterly payments due?

April 15, June 15, September 15, and January 15 of the following year. The 'quarters' are 3-2-3-4 months long, nobody knows why, everybody misses June once.

What happens if I skip a quarterly payment?

An underpayment penalty, effectively interest (around 8% annualized recently) on the shortfall, not a fine. Unpleasant, not catastrophic. The safe-harbor rule is the reliable way to make penalties impossible.

How much should I just set aside from every invoice?

25–30% into a separate account for most mid-income freelancers covers federal SE + income tax. Run your real number here, then automate the transfer the day invoices get paid.

Calculators

Quarterly estimated tax calculator

The IRS wants freelancers to pay as they earn, four times a year. This estimates a single filer's federal quarterly payment from expected profit, self-employment tax first, then income tax on what remains.

Your numbers

Expected annual net profit

Revenue minus deductible business expenses, your Schedule C bottom line, not your revenue.

Other taxable income

W-2 salary, interest, anything that stacks on top and pushes you into higher brackets.

Last year's total federal tax (optional)

Used for the safe-harbor check: pay 100% of last year's tax (110% if you earned over $150k) and you avoid penalties regardless of this year's bill.

What the ledger says

Set aside per quarter$5,683/quarter

Self-employment tax: $12,717
Estimated federal income tax: $10,015
Estimated total federal bill: $22,732
Effective rate on profit: 25.3%

Safe harbor: Enter last year's tax to see your penalty-proof safe-harbor payment.

Estimate, not advice

The formula

SE tax = profit × 92.35% × 15.3% (Social Security portion capped at the annual wage base; half of SE tax is deductible). Income tax = 2025 single-filer brackets applied to (profit − ½ SE tax − standard deduction + other income), minus the tax attributable to other income alone.

What this ignores

State and local tax, the QBI deduction, itemized deductions, credits, retirement contributions, and filing statuses other than single. 2025 tax year constants. It estimates the order of magnitude, your accountant sets the actual number.

Uses 2025 IRS constants (standard deduction $15,000; Social Security wage base $176,100).

Field notes

When are quarterly payments due?: April 15, June 15, September 15, and January 15 of the following year. The 'quarters' are 3-2-3-4 months long, nobody knows why, everybody misses June once.
What happens if I skip a quarterly payment?: An underpayment penalty, effectively interest (around 8% annualized recently) on the shortfall, not a fine. Unpleasant, not catastrophic. The safe-harbor rule is the reliable way to make penalties impossible.
How much should I just set aside from every invoice?: 25–30% into a separate account for most mid-income freelancers covers federal SE + income tax. Run your real number here, then automate the transfer the day invoices get paid.