"Estimated Tax Calculator (2026) — Free & No Signup

If income arrives without withholding — freelancing, contracting, rental income, investment gains — the IRS expects you to pay as you earn, in four quarterly installments. Miss the mark and an underpayment penalty accrues even if you pay in full at filing time. This calculator computes your required quarterly payments under both safe-harbor rules, shows the four due dates with amounts, and reconciles what you've already paid. Free, no signup, full formula visible, snapshot-replayable, and every input stays in your browser — nothing to file, nothing to install, just the schedule and amounts.

Filing status. Sets the bracket table for the current-year estimate.

Expected annual income. Total income for the year, including self-employment income (run the self-employment tax calculator first if unsure of your SE tax).

Expected deductions. Standard or itemized; reduces the current-year tax estimate.

Prior-year total tax. The "total tax" line from last year's return — the anchor of the safe-harbor rules. Enter it exactly as filed.

Prior-year AGI. Determines which safe-harbor rule applies: if it exceeded $150,000 ($75,000 if married filing separately), the higher-percentage rule kicks in.

Already withheld this year. W-2 withholding and any payments made so far both count toward the thresholds; the calculator credits them.

Estimated payments made so far. YTD quarterly payments, so the remaining schedule reflects reality.

Rule A — 100% of prior-year tax. Pay at least last year's total tax, in withholding plus quarters, and no underpayment penalty applies regardless of how high this year's bill turns out. The conservative anchor.

Rule B — 110% if prior-year AGI > $150,000. Higher earners must clear 110% of the prior-year number for the same protection.

There is also a current-year route — paying enough to cover most of this year's actual tax — but it requires predicting income you may not fully control, which is why community discussions split between the "bold" camp (aim for break-even; one documented filer celebrated a $16 balance as near-perfect) and the "buffer" camp (deliberately overpay for insurance). We present both rules and let you choose; the penalty mechanics are covered in our underpayment guide.

Current-year estimate = bracket math on (income − deductions) + SE tax (if applicable).
Safe-harbor target = prior-year tax × 100% (or × 110% if the AGI threshold applied).
Remaining requirement = max(target, current-year estimate) − withholding − payments already made.
Quarterly installment = remaining ÷ installments left, each mapped to its IRS due date.

Safe-harbor percentages: 100% / 110%; AGI threshold: $150,000 ($75,000 MFS).
Four quarterly due dates per IRS schedule (April, June, September, January).
Bracket tables per year; 2026 thresholds pending IRS first-hand verification.
Sources: IRS Publication 505; Form 1040-ES.

This calculator produces an estimate for planning purposes. It is not tax advice, and it is not a substitute for filing an accurate return.

Frequently asked

**What is the safe harbor rule for estimated taxes?**

Pay at least 100% of last year's total tax (110% if your prior-year AGI exceeded $150,000), across withholding and quarterly payments, and you avoid the underpayment penalty no matter what this year's final bill is.

I'm a W-2 employee with a side gig — do I need quarterly payments? Often you can skip quarters entirely by raising W-4 withholding instead: extra withholding is treated as paid evenly across the year. The withholding calculator computes a 4c amount that covers your side income.

What happens if I underpay? An underpayment penalty accrues from each missed due date — computed on IRS Form 2210 — even if you settle the full balance at filing. The safe-harbor rules above are the standard shields.

When are quarterly payments due? Four dates: mid-April, mid-June, mid-September, and mid-January of the following year. The calculator maps each remaining installment to its date.