Narelle Hartigan, CPA

Narelle Hartigan spent twelve years answering one question in different forms: why is this number on my payslip what it is? First in payroll, running weekly, fortnightly and monthly pay cycles through Single Touch Payroll and processing the TFN declarations that set every employee's withholding. Then in public practice, preparing individual and sole trader returns, lodging PAYG instalment variations and registering employers for withholding.

The pattern across both jobs was the same. People do not struggle with tax because the rates are secret; the ATO publishes everything. They struggle because the published material answers the ATO's questions, not theirs. Nobody at the tax office explains why a second job feels over-taxed, why an instalment notice arrives after one good year, or what a HELP debt actually does to a fortnightly pay.

This site is the answer sheet she wished she could hand across the desk. Every calculator runs on one tax engine built from the ATO's published 2026-27 rates, every guide leads with the number you came for, and everything is refreshed each 1 July when new rates land. The method is documented on the methodology page.

Narelle holds a Bachelor of Commerce in accounting and is a CPA. She is based in Sydney.