Percentage Calculator

Percentage calculations are among the most frequently performed mental arithmetic operations in daily life — yet they are also among the most frequently botched. Whether you are calculating a restaurant tip, figuring out how much you save in a sale, determining a mortgage rate's monthly impact, or trying to understand whether your investment has grown by 12% or shrunk by 8%, percentage errors are both common and costly. Our percentage calculator eliminates that risk entirely by offering five dedicated calculation modes in a single, instantly accessible interface: X% of Y (the classic percentage-of-a-number), Percentage Change (increase or decrease from A to B), X is what % of Y (reverse percentage), Add a percentage (price after markup or tax), and Subtract a percentage (price after discount). Each mode shows the complete formula alongside the result, so you always understand the calculation — not just the answer.

Percentage calculations and tip calculations are closely related daily financial operations — both involve applying a percentage rate to a base number. Our dedicated Tip Calculator goes further for dining specifically: it handles bill splitting among multiple people, calculates each person's share including tip, and accounts for different tipping conventions across countries — making it the more contextually appropriate tool for restaurant scenarios, while our percentage machine handles every other percentage challenge with equal versatility.

For those building stronger numeracy skills, percentage and prime number theory are two foundational pillars of number sense that reinforce each other. Our Prime Number Checker offers a fascinating complement: it reveals the prime factorisation of any composite number — which is, at its core, the mathematical equivalent of breaking a number down to its most fundamental percentage components. Together, these two tools make an excellent mathematical toolkit for students, educators and lifelong learners.