💸Quarterly Estimated Tax Calculator 2026

What it is

A full-year federal estimate for self-employed people: self-employment tax plus income tax on 2026 figures, sized to the IRS safe-harbor rules and divided across the four Form 1040-ES payment vouchers with their due dates.

How it works

The engine runs Schedule SE math, subtracts half the SE tax and the standard deduction ($16,100 single / $32,200 joint in 2026), applies the simplified 20% QBI deduction below the §199A thresholds, walks the verified 2026 bracket schedule, then compares 90% of the current-year figure against 100–110% of last year’s tax to pick the smaller safe harbor.

Getting the most from it

1. Enter net self-employment profit, or gross income and expenses where presets are offered.
2. Add other income and any W-2 withholding — withholding counts as already paid.
3. Enter last year’s total tax and AGI to activate the prior-year safe harbor comparison.
4. Review the per-voucher amount and download the deadline calendar so no date slips.

Reading your result

The per-quarter figure is the annual required payment divided by four, after withholding. The result names which safe-harbor basis it used — 90% of this year or a percentage of last year — so the number can be traced straight back to the 1040-ES worksheet logic.

What it can't tell you

It estimates federal tax only — no state estimates, credits, itemized deductions, or uneven-income annualization, and above the QBI threshold it computes without §199A rather than guessing. The IRS worksheet and a professional handle those layers.