Math Tools
A fast way to run the percentage calculations that come up everywhere — a discount, a tip, a grade, a statistic — without doing the arithmetic by hand or reaching for a calculator app.
Average & Standard Deviation Calculator
Mean, median, mode, range, and population/sample standard deviation, all at once.
OpenFraction Calculator
Add, subtract, multiply, or divide fractions, simplified automatically.
OpenGCD & LCM Calculator
Find the GCD and LCM of two or more whole numbers at once.
OpenPercentage Calculator
Find X% of Y, what percent X is of Y, and percentage change between two numbers.
OpenQuadratic Equation Solver
Solve a quadratic equation for its roots, discriminant, vertex, and axis of symmetry.
OpenRatio Calculator
Simplify a ratio to lowest terms, or solve A:B = C:D for a missing value.
OpenScientific Calculator
Type or tap an expression with trig, log, powers, and roots, and see the result live.
OpenPercentage Calculator handles the common percentage questions in one place: what is X% of Y, what percentage is X of Y, and percentage increase or decrease between two numbers. These sound simple individually but people mix up the formula for each one constantly — this tool removes the guesswork.
It's built for the moment the math actually needs to happen: checking a discount at checkout, working out a tip percentage, understanding a statistic in an article, or figuring out how much a value grew or shrank between two points.
This category, like Converters and Health, starts with one well-built tool rather than a dozen thin ones — more math tools get added here as real search demand justifies them, following the same standard as the rest of the site.
What you can use it for
- Calculate what a discount percentage actually takes off a price
- Work out what percentage one number is of another (test scores, statistics, proportions)
- Calculate percentage increase or decrease between two values
- Reverse-calculate an original price from a discounted price and percentage
Frequently asked questions
How do I calculate percentage increase?
Percentage increase = ((new value − old value) ÷ old value) × 100. The calculator does this automatically when you enter both values — you don't need to remember the formula.
Is my data sent anywhere?
No — every calculation runs in your browser as plain JavaScript arithmetic. Nothing is transmitted or stored.
Can this calculate compound percentage changes over multiple steps?
It handles single before/after percentage calculations. For compounding growth over multiple periods (like investment returns), use the Compound Interest Calculator in Finance Tools instead.
Does it round the result?
Results are shown with enough decimal precision to be useful for real-world numbers like prices and grades, without unnecessary trailing digits.