How quarterly estimated taxes work
If you're self-employed and expect to owe more than $1,000 in federal tax for the year, the IRS requires you to pay estimated taxes four times a year. This is because there's no employer withholding taxes from your paycheck — you're responsible for making regular payments throughout the year.
Skipping quarterly payments doesn't result in a large penalty, but it does result in a compounding underpayment penalty on the amount you should have paid, calculated daily at the federal short-term rate + 3 percentage points (currently around 8% annualized).
The safe harbor rule — your protection against penalties
The safest approach to quarterly taxes is using the safe harbor rule:
- Standard safe harbor: Pay 100% of last year's total tax in quarterly installments (25% each quarter). Even if you earn much more this year, you won't be penalized.
- High-income safe harbor: If your prior year AGI exceeded $150,000, pay 110% of last year's tax to avoid penalties.
- Current year safe harbor: Alternatively, pay at least 90% of your current year's actual tax liability — but this requires estimating accurately throughout the year.
When safe harbor is most useful: If your income varies significantly year to year (common for freelancers, creators, and gig workers), the prior-year safe harbor removes the guesswork. You pay based on a number you already know — last year's tax return — not on projections.
2025 quarterly tax deadlines
The IRS quarterly deadlines for 2025 tax year payments:
- April 15, 2025 — Q1 payment (income earned January–March)
- June 16, 2025 — Q2 payment (income earned April–May)
- September 15, 2025 — Q3 payment (income earned June–August)
- January 15, 2026 — Q4 payment (income earned September–December)
Pay at IRS.gov/payments using Direct Pay (free, bank account) or EFTPS (free, but requires registration). Both are instant — you'll receive immediate confirmation.
California is different: California's estimated payment schedule is not evenly spread. CA requires 30% by April 15, 40% by June 15, and 30% by January 15 — there's no September installment. If you're a California resident, pay your CA and federal payments on different schedules.
How to calculate your quarterly payment (without the calculator)
- Estimate your annual net profit — gross self-employment income minus business expenses
- Calculate SE tax: net profit × 0.9235 × 0.153 (the 0.9235 accounts for the employer deduction)
- Deduct half of SE tax from net profit to get adjusted net profit
- Apply federal income tax brackets to adjusted net profit plus any other income
- Add SE tax + income tax for annual tax liability
- Divide by 4 for quarterly payment amount
The calculator above does all of this automatically. If your income is irregular, recalculate each quarter based on year-to-date earnings.
What to do if you missed a quarterly payment
Pay it immediately. The underpayment penalty accrues daily on the amount that should have been paid. Paying late stops the penalty clock from running — it doesn't eliminate what's already accrued, but it prevents more from adding up. When you file your return, IRS Form 2210 calculates any penalty owed; for small amounts, the IRS often waives it or includes it in your balance due without separate action.
Setting up a quarterly tax system that actually works
The simplest system used by thousands of self-employed people:
- Open a dedicated savings account labeled "Taxes"
- Every time you receive a payment, move 25–30% to that account immediately
- Pay the quarterly estimate from that account by each deadline
- Any balance remaining after your Q4 payment is yours to keep
If you only set aside money after seeing a large profit, you'll spend it. The automatic transfer on every payment makes the discipline structural rather than willpower-based.