Math Calculators

Percentages, fractions, exponents, ratios and other core maths tools with worked examples.

All math calculators

• Antilog CalculatorEnter a logarithm value and, if you like, a base, and get the number it came from. Leave the base empty to work with the natural logarithm (base e).
• Arithmetic Mean CalculatorEnter any list of numbers and the calculator returns their arithmetic mean together with how many values it used. The guide covers the formula, useful properties, and the situations where an average can mislead.
• Binary Calculator & ConverterUse it as a converter between binary, decimal and hexadecimal, or switch to calculator mode to add, subtract, multiply and divide two binary numbers.
• Cube Root CalculatorEnter a number and get its cube root, the value that multiplied by itself three times gives your number. The guide below explains how to check the result by hand.
• Decimal to Fraction CalculatorType a decimal and get the matching fraction in lowest terms, plus the mixed-number form when the value is above 1.
• Decimal to Percent CalculatorEnter a decimal such as 0.35 and get the percentage, 35%. The guide explains the rule and how the result is rounded.
• Exponent CalculatorType a base and an exponent and get the power straight away. The guide below covers the exponent rules, negative and fractional powers, and what to expect from very large or very small results.
• Fraction CalculatorWork with simple fractions, mixed numbers and decimals in basic mode, or type a whole expression with brackets in advanced mode. Every answer comes as a decimal and as a mixed fraction.
• Fraction to Decimal CalculatorEnter the top and bottom of a fraction and the calculator divides them for you. The guide explains how the conversion works, why some fractions repeat forever and lists the decimals you will meet most often.
• Fraction to Percent CalculatorType the numerator and denominator of a fraction to see it as a percentage. The guide shows the formula, a mental shortcut for denominators such as 20 and 25, and a table of everyday fractions.
• Geometric Mean CalculatorEnter a list of positive numbers, or a list of percentage changes, and get the geometric mean to 12 decimal places. The guide explains the formula, when to prefer it over the ordinary average and how zeros and negative values are treated.
• Greatest Common Divisor (GCD) CalculatorPaste or type two or more numbers and get their greatest common divisor in one click. The guide shows three ways to find it by hand and what the result is good for.
• Harmonic Mean CalculatorEnter your numbers separated by commas, spaces or new lines and the tool returns their harmonic mean, rounded to four decimals. The guide explains when this average is the right one and how to check it by hand.
• Hex Calculator & ConverterPick Converter to translate a value between hex, decimal and binary, or Calculator to do arithmetic on two hex numbers. Results appear in hex and decimal together, and the guide below shows how to get the same answers by hand.
• Least Common Denominator (LCD) CalculatorType your fractions as numerator/denominator and the calculator returns the smallest denominator they can all share. Below you will find the step-by-step method and a full example.
• Least Common Multiple (LCM) CalculatorList two or more whole numbers and get their least common multiple, the smallest positive number that every one of them divides evenly. The guide below shows three ways to find it by hand.
• Logarithm CalculatorEnter a number and a base to get log base b of x, or leave the base empty for the natural logarithm. The guide explains what a logarithm means and the rules for working with them.
• Mean, Median & Mode CalculatorType or paste a list of numbers, separated by commas, spaces or new lines, and press Calculate. You get the mean, median, mode, range and the number of values at once; the guide below explains how each one is worked out.
• Median CalculatorEnter your numbers, separated by commas, spaces or new lines, and press the button to find the median: the value that splits the sorted list into a lower half and an upper half.
• Mode CalculatorEnter your numbers, separated by commas, spaces or new lines, and press the button. The calculator reports the value that occurs most often, or lists all of them when several tie.
• Percent to Decimal CalculatorType a percentage and press the button to see it as a decimal number. The guide below explains the rule, shows worked examples and includes a reference table of common values.
• Percent to Fraction CalculatorEnter a percentage to see it written as a fraction in lowest terms, or as a mixed number when it is above 100%. The guide below shows how to do the conversion by hand and lists the fractions you will meet most often.
• Percentage CalculatorPick the question you need answered, enter two numbers and get the result instantly. The guide below shows the formula behind each mode.
• Percentage Decrease CalculatorChoose whether you want to take a percentage off a number or find the percentage drop between two values, fill in the fields and press Calculate. The guide below shows the formula and several worked cases.
• Percentage Increase CalculatorChoose whether to add a percentage to a number or to measure how much one value grew into another, enter the figures and press Calculate. The guide below explains the formulas and walks through examples.
• Proportion CalculatorEnter three of the four numbers in two equal fractions and leave one box empty. The calculator solves for the missing term and the guide explains the cross-multiplication rule behind it.
• Ratio CalculatorFill in three of the four numbers in a:b = c:d, leave one empty and read off the missing value. The guide covers simplifying and combining ratios, odds and screen aspect ratios.
• Root CalculatorType a number and the degree of the root you want. Square roots, cube roots, fourth roots and fractional roots all work the same way.
• Scientific Notation Calculator & ConverterSwitch between the converter and the calculator at the top. Convert a number between decimal and scientific form, or do arithmetic on two numbers written in e-notation.
• Sequence CalculatorPick a sequence type, enter the starting number and the common difference or ratio, and choose which term you want. You get that term, the running total and a short stretch of the sequence around it.
• Significant Figures CalculatorChoose a mode: round a number to a set count of significant figures, count the significant figures in a number, or calculate with two measured values. The guide covers the rules, rounding methods and worked examples.
• Simplify Fractions CalculatorType a fraction as numerator/denominator and the calculator reduces it to lowest terms, showing a mixed number when the fraction is improper. The guide explains the method so you can check the result by hand.
• Square Root CalculatorType a positive number and the calculator returns its principal square root, exact for perfect squares and rounded to six decimals otherwise. The guide below explains what the result means and how to check it by hand.
• Standard Form CalculatorEnter a number in ordinary decimal form and the calculator rewrites it in standard form, a number from 1 to 10 multiplied by a power of ten, together with the matching e-notation.
• Summation CalculatorUse Simple sum to total a list of numbers, or Sigma notation to add up a formula such as 2n+3 for every whole step between a lower and an upper limit. The guide explains the notation and the closed-form shortcuts.
• Weighted Average CalculatorEnter one value and its weight per line and the calculator returns the weighted mean. The guide shows the formula and how to use it for course grades, average prices and similar problems.