16 free calculators
Math
Clear tools for percentages, discounts and practical number problems.
Tools in this category
Percentage Calculator
Calculate a percentage of any number instantly.
Discount Calculator
Find the final price and savings after a discount.
Percentage Increase Calculator
Increase a value by a chosen percentage and see the exact change.
Percentage Decrease Calculator
Reduce a value by a percentage and calculate the amount removed.
Average Calculator
Find the arithmetic mean of up to four numbers.
Ratio Calculator
Simplify a two-number ratio to its lowest whole-number terms.
Fraction Calculator
Add two fractions and simplify the result automatically.
Median Calculator
Find the middle value of a set of up to six numbers.
Mode Calculator
Identify the most frequent value or values in a six-number data set.
Standard Deviation Calculator
Calculate population and sample standard deviation for six values.
Percentage Difference Calculator
Compare two values using their absolute difference and average.
Circle Area Calculator
Calculate a circle’s area and circumference from its radius.
Rectangle Area Calculator
Calculate the area and perimeter of a rectangle.
Triangle Area Calculator
Calculate a triangle’s area from its base and perpendicular height.
Pythagorean Theorem Calculator
Find the hypotenuse of a right triangle from its two perpendicular sides.
Cylinder Volume Calculator
Calculate a cylinder’s volume and surface area from radius and height.
Understand the calculations
Use these focused guides and worked articles to check formulas, assumptions and practical examples.
Continue exploring
Math
Understand the formula
These are the actual formulas used by the linked tools.
R = A × p ÷ 100
F = O × (1 − r ÷ 100)
N = B × (1 + r ÷ 100)
Math
See the numbers in practice
Use these worked examples as a reference before entering your own values.
150 × 20 ÷ 100 = 30
€120 × 25% = €30 · €120 − €30 = €90
100 × (1 + 15 ÷ 100) = 115
Math
Compare your scenarios
Keep your starting values, change one input and calculate again. Record both results to see which assumption makes the difference.
Percentage Calculator