Practitioner-grade income tax calculators built from primary sources: the IRS, HMRC, ATO, IRAS, and CRA. Each tool shows its methodology, cites every input, and lists what it does not cover.
IRS Rev. Proc. 2025-32 brackets, standard deduction, OBBBA senior bonus, FICA, Child Tax Credit.
England/Wales/NI or Scotland bands, Class 1 NI, student loan plans, Personal Allowance taper, salary sacrifice + relief-at-source pensions.
ATO post-Stage-3 brackets plus the 2% Medicare Levy. Resident rates only.
IRAS 13-band resident progressive schedule, 0% to 24%.
CRA federal brackets and Basic Personal Amount. Provincial / territorial tax calculated separately.
Schedule SE 12.4% SS + 2.9% Medicare, half-SE deduction, federal income tax estimate, quarterly payment, W-2 equivalent comparison.
Pairwise income tax burden comparisons across the five country calculators. Effective and marginal rates at sample USD income levels, native-currency figures alongside.