Calk-AU: Aussie Calculators

124 free calculators on the latest 2025–26 ATO rates. Works fully offline — and updates itself when the rules change. Tax, pay, mortgage, super, GST and more.

Calk-AU puts 124 free Australian calculators in your pocket — tax, pay, mortgage, super, GST and far more — all built on the current 2025–26 ATO rates.

No sign-up. No paywall. And it works 100% offline: run any calculation on the train, in a meeting or out of range. When the rates or rules change, the app updates its formulas automatically — so your numbers are always current.

KNOW YOUR REAL MONEY • Income Tax — 2025–26 brackets, Medicare levy and the low-income offset • Pay Calculator — take-home pay after tax, super and HECS • HECS-HELP — the new marginal repayment system • GST — add or remove 10% in a tap • Capital Gains, FBT, PAYG, payroll tax and more

PROPERTY & LENDING • Mortgage repayments, offset savings and extra-repayment scenarios • Borrowing power, LMI, stamp duty and first-home-buyer help by state • Car, personal and comparison-rate loan tools

SUPER, BUDGET & LIFE • Superannuation, employer contributions and pensions • Budget planner, net worth, compound interest and FIRE • Health, vehicle and energy calculators

MADE FOR THE APP • Save any calculation to your history • Favourite the tools you use most • Share results via WhatsApp, email or SMS • Light and dark mode

Every formula is based on official ATO, Services Australia and state-revenue rules, with clear breakdowns so you can see exactly how each number is worked out.

Calk-AU is free to use. It provides estimates for general information and isn't financial or tax advice.