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Quarterly Estimated Tax Calculator

Figure out what to send the IRS each quarter — with safe-harbor rules applied automatically so you avoid underpayment penalties without overpaying all year.

Business/1099 income minus business expenses.

Withholding counts as paid evenly through the year — it reduces what you must send quarterly.

Used for the prior-year safe harbor. Leave 0 if you don't know it.

How estimated taxes actually work

The U.S. tax system is pay-as-you-go. Employees prepay through withholding; the self-employed prepay through four 1040-ES estimated payments. Miss them and the IRS charges an interest-style penalty — even if you pay in full at filing time.

The good news is the safe harbor: you're penalty-proof if you pay in at least 90% of this year's tax, or 100% of last year's (110% for higher incomes), whichever is less. In a growth year, the prior-year safe harbor is often dramatically cheaper — this calculator picks the smaller number for you automatically.

If your income is lumpy — common in oilfield contracting, consulting, and seasonal businesses — you may do better with the annualized-income method, which matches payments to when you actually earn. That's a good problem to hand a CPA.

Estimated Tax Questions

Who has to pay quarterly estimated taxes?
Generally, anyone who expects to owe at least $1,000 in federal tax after withholding — most commonly freelancers, 1099 contractors, business owners, landlords, and investors. If you also have a W-2 job, increasing your withholding can substitute for estimated payments.
What is the safe harbor rule for estimated taxes?
You avoid an underpayment penalty if you pay in at least 90% of this year's tax or 100% of last year's tax (110% if your prior-year AGI was over $150,000), whichever is smaller. Many taxpayers simply pay the prior-year safe harbor amount for certainty.
When are quarterly estimated taxes due?
For tax year 2026: April 15, June 15, and September 15, 2026, and January 15, 2027. The "quarters" are uneven — Q2 covers only two months — so mark the actual dates, not every three months.
What happens if I miss an estimated tax payment?
The IRS charges an underpayment penalty that works like interest on the shortfall from the due date until you pay. Catching up in the next quarter reduces further penalties but doesn't erase what already accrued — so paying something on time beats paying everything late.
Estimates only — not tax advice. This tool assumes the standard deduction, simplified QBI treatment, and evenly earned income. It does not model state taxes, credits, capital gains, or the annualized-income method. Confirm your voucher amounts with a licensed CPA.

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We calculate exact vouchers for our clients, adjust them mid-year when income changes, and send reminders before every deadline.

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