About Us
Free, accurate percentage calculators that explain every answer.
Our mission
Calculatorza exists to make percentage maths fast, accurate and easy to understand. Whether you're a student checking exam marks, a shopper adding GST, a business owner working out profit and loss or a teacher explaining the basics, our calculators give you the right answer in seconds — and show you how it was worked out.
What makes us different
- Real-time results — answers update as you type, with no page reloads.
- Step-by-step working — every result shows the formula and each step, so you can learn the method, not just copy a number.
- Careful maths — we handle decimals, negative numbers, rounding noise and division-by-zero cases properly.
- Private by design — calculations run in your browser. We never ask you to sign up, and the numbers you type are not sent to us.
- Fast and accessible — lightweight pages that work on any device and with a keyboard or screen reader.
Our calculators
We offer six free tools: the Percent Calculator, the profit & loss calculator, the sales tax / GST calculator, the age calculator, the scientific calculator and the currency converter. See them all.
Get in touch
Spotted a bug or want a new calculator? We'd love to hear from you on our contact page.