How estimated taxes work
When you have a job, your employer withholds tax from every paycheck and sends it to the IRS for you. When you're self-employed, nobody does that — so the IRS asks you to pay as you go, in four estimated installments across the year. If you expect to owe $1,000 or more after withholding, you're generally on the hook for these payments.
For self-employment income, each payment has to cover two taxes: self-employment tax (about 15.3% for Social Security and Medicare, on 92.35% of your net profit) and federal income tax on what's left after the deductions you're entitled to. This calculator estimates both, applies a simplified qualified business income (QBI) deduction and the standard deduction for your filing status, and divides the total into four to show a per-quarter number.
Federal estimated payments are due roughly April 15, June 15, September 15, and January 15 of the next year (dates shift for weekends and holidays — always confirm the current year's deadlines).
The safe-harbor shortcut
If projecting your income feels like guesswork, there's a simpler way to stay penalty-free: the safe-harbor rule. Pay at least 100% of last year's total tax across your four payments — or 110% if your prior-year adjusted gross income was over $150,000 — and the IRS won't charge an underpayment penalty, even if you end up owing more at filing. Many owners use safe harbor for predictability and simply true up the balance when they file. This calculator uses the projected-income method instead, which is more precise when your income is steady; check both and pay the one that fits your situation.
What this calculator doesn't include
To keep it simple, this is a federal-only estimate. It does not include your state or local estimated taxes (many states require their own), tax credits (child tax credit, education credits, and others), retirement or health-insurance deductions, the 0.9% additional Medicare tax, or the income limits and phase-outs on the QBI deduction. Any of those can move your real payment up or down. Treat the number as a starting point, and confirm your actual quarterly amount with a qualified CPA or tax pro — something that's far easier when your books are current every month.
Related reading: our full guide to quarterly estimated taxes, the tax season prep checklist, S-Corp vs LLC, and our S-Corp savings calculator, or the whole system in our complete guide to small business bookkeeping.
Estimated tax FAQ
Who has to pay quarterly estimated taxes?
Generally, if you expect to owe at least $1,000 in federal tax for the year after withholding and credits, and you don't have enough tax withheld from a paycheck to cover it, you're expected to make quarterly estimated payments. That covers most self-employed people, freelancers, single-member LLC owners, S-Corp shareholders taking distributions, landlords, and anyone with significant income that isn't subject to withholding.
When are quarterly estimated taxes due?
Federal estimated taxes are due four times a year — roughly April 15, June 15, September 15, and January 15 of the following year. The periods aren't even calendar quarters, and dates shift when they fall on a weekend or holiday, so confirm the exact deadlines each year. Missing a payment can trigger an underpayment penalty even if you pay in full by the annual filing deadline.
How much should I pay in estimated taxes?
You generally want each payment to cover roughly a quarter of your expected total tax for the year — which for self-employment income means both self-employment (FICA) tax and income tax. A common shortcut is the safe-harbor rule: pay at least 100% of last year's total tax (110% if your prior-year adjusted gross income was over $150,000), split into four payments, and you'll avoid the underpayment penalty even if you end up owing more. This calculator estimates from your projected profit; the safe-harbor amount is an alternative worth checking.
What happens if I underpay my estimated taxes?
The IRS charges an underpayment penalty, which works like interest on the amount you should have paid each quarter but didn't. It's usually not huge, but it's avoidable — and it compounds if you skip multiple quarters. The simplest protection is meeting the safe-harbor threshold (100% or 110% of last year's tax). Setting aside a fixed percentage of each deposit as it comes in, and reconciling your books monthly, keeps you from being surprised at deadline time.
Is this estimated tax calculator tax advice?
No. It's a simplified educational estimate of your federal payment only, not tax, legal, or financial advice. It uses standard federal self-employment and income-tax figures and a simplified QBI deduction; it does not include state or local estimated taxes, tax credits, other deductions, additional Medicare tax, or the specifics of your return. Use it as a directional guide, then confirm your actual payments with a qualified CPA or tax professional. Clean, current books make that calculation far more accurate.