47 free calculators across electronics, transport, weather, internet utilities, date & time, and everyday tools.
Age, date arithmetic, durations, timesheets and time zones — see the full Date & Time Calculators hub for all of these plus a guide to Australian time zones and timesheet rules.
Everything here solves a practical problem that does not fit neatly under tax, finance, health or maths. Sizing an inverter, converting an American recipe, working out whether a tyre change will throw out your speedometer, checking a subnet mask. Different fields, same idea: a specific calculation you need occasionally and would rather not do by hand.
Every calculator on this page is free, needs no sign-up, and runs entirely in your browser. Nothing you type is sent anywhere.
| What you need | Use this |
|---|---|
| Convert cups to grams for a US recipe | Cooking Converter |
| Convert between any units | Unit Converter |
| Convert height between cm and feet | Height Calculator |
| Size a solar system or battery bank | Solar Panel Calculator |
| Work out voltage drop over a cable run | Voltage Drop Calculator |
| Check fuel costs for a trip | Fuel Cost Calculator |
| See if a tyre size change affects your speedo | Tyre Size Calculator |
| Calculate a GPA or WAM | GPA & WAM Calculator |
| Work out what you need on a final exam | Grade Calculator |
| Find the molar mass of a compound | Molecular Weight Calculator |
| Work out a subnet range | IP Subnet Calculator |
| Check the apparent temperature on a hot day | Heat Index Calculator |
| Work out your exact age or days between dates | Date & Time Calculators |
| Convert a timesheet to decimal hours and pay | Time Card Calculator |
Most conversion tools online assume American defaults, and the gap is wider than it looks. An Australian cup is 250 mL against the US 236.6 mL. An Australian tablespoon is 20 mL where nearly everywhere else uses 15 mL — a third larger, which matters in a spice mix or a raising agent. Fuel economy here is litres per 100 kilometres, not miles per gallon, and the two run in opposite directions: a lower number is better for one, worse for the other.
The calculators here use metric by default and name their assumptions. Where a figure differs by country, you can pick which standard you are working from rather than guessing which one a tool has silently applied.
These pair naturally with the more specialised sections. If you are pricing a renovation, the measurement converters feed into the building calculators. If you are working out running costs, the transport tools sit alongside the financial calculators. Student tools connect to the maths and statistics sections.
Each calculator page includes a plain-English explanation of the method, worked examples where the arithmetic is not obvious, and the assumptions behind any figure that varies by country or context.
Are these calculators free?
Yes, all of them, with no sign-up and no limits. They run in your browser, so nothing you enter is transmitted or stored.
Do they work on a phone?
Yes. Every calculator is built to work on a phone screen, which is where most people use them — in a kitchen, a shed or a car park rather than at a desk.
Why do some results differ from other websites?
Usually because of unit standards or assumptions. Cup sizes, tablespoon sizes and fuel economy conventions differ between countries, and many tools apply American defaults without saying so. Our calculators state which standard they are using and let you change it.
Can I rely on these for professional work?
They are accurate for the calculation they perform, but they are general tools rather than a substitute for a licensed professional. Electrical, structural and regulated work should be checked against the relevant Australian Standard and signed off by someone qualified.