Math calculators
Percentages, fractions, averages, statistics, algebra and geometry, with exact answers where possible and the working shown so you can check it.
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Percentage calculator
Find X% of Y, find what percent X is of Y, or find the whole when X is Y% of it. Uses exact decimal math.
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Percentage change calculator
Compare a positive starting value with a new value to find the percentage increase or decrease.
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Ratio calculator
Reduce two numbers to their simplest whole-number ratio, such as 1920:1080 to 16:9. Decimals, fractions and negative numbers work too.
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Proportion calculator
Find one missing value in two equal ratios. Put x in any one of the four positions.
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Average calculator
Find the average (arithmetic mean), sum and count of up to 5,000 numbers. Separate numbers with commas, spaces or new lines.
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Median calculator
Find the middle value after sorting. An even-sized list uses the mean of its two middle values. Separate numbers with commas, spaces or new lines.
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Standard deviation calculator
Measure how widely numbers vary around their mean. Use sample for a subset of a larger group, or population for the complete group.
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Weighted average calculator
Combine values that have different importance or counts, such as grades and their weights. Weights must be zero or more, with at least one above zero.
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Number range summarizer
Summarize a list of numbers with its range, minimum, maximum, sum, mean and median. Separate numbers with commas, spaces or new lines.
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Fraction calculator
Add, subtract, multiply or divide two fractions, mixed numbers or decimals and get an exact simplified fraction.
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Fraction to decimal
Convert a fraction or mixed number to a decimal and percent, and show which digits repeat. Long decimals are rounded to your chosen places.
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Decimal to fraction
Convert a finite decimal to an exact simplified fraction. Scientific notation is supported. Use at most 80 digits and an input exponent from -100 to 100.
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Scientific notation converter
Write a finite decimal as a number times a power of ten, without losing digits. Use at most 80 digits and an input exponent from -100 to 100.
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Significant figures calculator
Count and round significant figures. Leading zeros do not count, and whole-number trailing zeros without a decimal point are treated as placeholders. Ties round away from zero.
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Rounding calculator
Round a number exactly, including negative numbers and ties. Negative decimal places round to tens, hundreds or larger. Supports up to 200 digits.
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Prime factorization
Break a whole number up to one trillion into prime factors, and count its divisors. Use the factors to simplify fractions or compare shared divisors.
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Greatest common divisor
Find the largest whole number that divides every number in a list, also called the greatest common factor. Use it to reduce fractions or split into equal groups.
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Least common multiple
Find the smallest shared multiple of whole numbers. Use it for common denominators or to find when repeating intervals line up.
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Combinations calculator
Count ways to choose k distinct items from n distinct items when order does not matter, such as lottery picks. Items are chosen without replacement.
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Permutations calculator
Count ordered arrangements of k distinct items chosen from n distinct items, such as first, second and third place. Items are chosen without replacement.
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Exponent calculator
Raise a base to a power, including negative and fractional exponents. Whole-number powers are exact up to 10,000 digits.
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Logarithm calculator
Find log base 10, e, 2 or any custom base of a positive number, with the change-of-base steps. Antilog mode raises the base to a power.
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Root calculator
Find the real square, cube or nth root of a number. Perfect powers are exact, and integer roots are simplified, such as √72 = 6√2.
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Quadratic equation solver
Solve ax² + bx + c = 0 for real or complex roots, with the discriminant, vertex and axis of symmetry. If a is 0 it solves the linear equation.
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Pythagorean theorem calculator
Enter any two sides of a right triangle, legs a and b or hypotenuse c, to find the third side plus area, perimeter and angles.
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Circle calculator
Start from a circle's radius, diameter, circumference or area and get all the other measurements, rounded to your chosen decimal places.
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Z-score calculator
Turn a value, mean and standard deviation into a z-score and normal percentile, or convert between z-scores and percentiles.
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Percentile calculator
Find the value at any percentile of a list of numbers using Excel-style or nearest-rank methods, and the percentile rank of a value.
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Linear regression calculator
Fit a least-squares line to x,y pairs to get the slope, intercept, equation, r and r squared, and predict y for a chosen x.
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Percent error calculator
Compare a measured value with the accepted value to get the absolute error, relative error and percent error. The accepted value cannot be 0.
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Factorial calculator
Compute n! or the double factorial n!! exactly for whole numbers from 0 to 5,000, with the digit count and trailing zeros.
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Mode calculator
Find the most common value or values in a list of numbers or text items, with a frequency table. Reports no mode when no value is more common.
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