Math
1,470 math calculators: percentages, fractions, equations, geometry, trigonometry, statistics and number theory. Each one shows the method in plain words, so you get the answer and understand how it was reached, free in your browser.
Cube volume calculator
Enter the side of a cube and get its volume, the side multiplied by itself three times: a side of 3 gives 27, in your unit cubed.
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Cubic feet of a cylinder
Enter a cylinder's radius and height in feet and get its capacity in cubic feet: a radius of 2 ft and a height of 5 ft hold 62.831853 cubic feet.
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Largest cube in a cylinder
Find the biggest cube that fits inside a cylinder: with a radius of 2 and a height of 5, the edge is 2.828427 and the volume 22.627414.
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Cubic yards of a cylinder
Turn a round hole, column or tank measured in feet into cubic yards for ordering concrete, gravel or mulch: a radius of 2 ft and a height of 5 ft come to…
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Cuboid calculator
Enter a box's length, width and height and get both its volume and its total surface area: 3 by 4 by 5 gives a volume of 60 and a surface of 94.
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Cuboid volume calculator
Multiply length, width and height to get the space a box, room or crate encloses: 3 by 4 by 5 gives 60, in your unit cubed.
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Cycloid
Enter the radius of a rolling wheel and get the length of one cycloid arch, the area beneath it or any point on the curve: a radius of 2 gives an arch 16 long…
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Cyclomatic complexity calculator
Count how many independent paths run through a function from three numbers on its control-flow graph: 9 edges, 8 nodes and 1 component give a complexity of 3…
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Cylinder circumference
Get the perimeter of a cylinder's round base from its radius or diameter, so a radius of 3 gives 18.849556.
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Cylinder diameter calculator
Find a cylinder's diameter from its volume and height. A volume of 1000 with a height of 10 gives a diameter of 11.2838 and a radius of 5.6419.
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Cylinder volume in gallons
Turn a cylinder measured in inches into US gallons: a radius of 6 inches and a height of 48 inches hold 23.500745 gallons.
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Cylinder volume in liters
Turn a cylinder measured in centimeters into liters: a radius of 10 cm and a height of 40 cm hold 12.566371 liters.
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Cylindrical coordinates converter
The point (3, 4, 5) becomes a radius of 5, an azimuth of about 0.9273 radians and a height of 5. The angle always lands in the right quadrant, even when x or y…
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Regular decagon
A regular decagon with a side of 4 encloses an area of 123.107341 square units. Choose the measurement you need: the area, the perimeter, the interior angle…
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Decimal expansion of a fraction
1/3 comes back as 0.(3) and 1/7 as 0.(142857), with the repeating block in parentheses, while a fraction that ends, like 1/8, gives a clean 0.125.
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Decimal to degrees and minutes converter
40.7128° becomes 40° 42.768′: whole degrees plus minutes with decimals, stopping before seconds, the way aviation reports, marine waypoint lists and telescope…
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Determinant calculator
The 2×2 matrix with rows (4, 3) and (6, 3) has a determinant of −6, so it can be inverted. Any square matrix up to 32×32 gets its determinant and a clear note…
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Diagonal of a rectangle
A rectangle 3 wide and 4 tall has a diagonal of exactly 5, worked out with the Pythagorean theorem and given in the unit you typed.
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Diagonalize a matrix
For the matrix with rows (2, 1) and (1, 2) you get the eigenvalues 3 and 1, the diagonal matrix D and the eigenvector matrix P, so that A = P·D·P⁻¹.
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Diameter of cone
Turn a cone's volume and height into the diameter of its base, which is twice √(3V ÷ (π·h)), without rearranging the formula by hand.
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IQR outlier detection calculator
Spot the values that sit far outside the middle half of your data: in 1, 2, 2, 3, 4 and 100 the fences fall at −1 and 7, so 100 is the only outlier.
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Median absolute deviation calculator
For 1, 1, 2, 2, 4, 6 and 9 the median is 2 and the median absolute deviation is 1: the distances from 2 are 1, 1, 0, 0, 2, 4 and 7, and their median is 1.
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Mode of a dataset calculator
In 1, 2, 2, 3 and 4 the mode is 2, reached twice, and a frequency table shows how often each value appears.
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Population variance calculator
The eight values 2, 4, 4, 4, 5, 5, 7 and 9 have a mean of 5 and a population variance of 4. Paste every value of the group and get the count, mean, sum of…
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Quintile calculator
For the numbers 1 to 10, the four quintile cuts are 2.8, 4.6, 6.4 and 8.2, the 20th, 40th, 60th and 80th percentiles.
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Standard error of the mean calculator
For 2, 4, 4, 4, 5, 5, 7, 9 the mean is 5 and its standard error is about three quarters of a unit, the sample standard deviation over the square root of 8.
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Winsorized Mean Calculator
Average data without letting extremes take over: for 1, 2, 3, 4 and 100 with a fraction of 0.2 per tail, the 1 becomes 2, the 100 becomes 4 and the winsorized…
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Class Width Calculator for Frequency Tables
Data running from 12 to 92 have a range of 80, so 8 classes give a class width of exactly 10. Enter the smallest value, the largest value and the number of…
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Cumulative Frequency Calculator for Class Counts
Class counts of 4, 7, 3 and 6 become running totals of 4, 11, 14 and 20, and the last figure is your total number of observations.
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Grouped data mode calculator
Estimate the most common value when data come grouped in classes: with boundaries 0, 10, 20, 30 and 40 and counts 5, 9, 12 and 7, the mode is 23.75, inside the…
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Moment coefficient of skewness calculator
For 1, 2, 3, 4, 5 and 12 the mean is 4.5, the third central moment is 60 and the moment coefficient of skewness is above 1, so the sample is labelled…
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Standardized moment calculator
For 1, 2, 3, 4, 5, 12 at order 3, the mean is 4.5 and the third central moment is 60; dividing it by the standard deviation cubed gives a positive skewness with…
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Kendall tau correlation calculator
Check whether two series rise and fall in the same order: for 1, 2, 3, 4 against 1, 3, 2, 4 there are 5 agreeing pairs and 1 disagreeing pair out of 6, so tau…
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Mean deviation about median calculator
For 1, 2, 3, 4 and 100 the median is 3 and the mean deviation about it is 20.2: the distances from the median add up to 101, and 101 divided by 5 is 20.2.
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Pearson mode skewness calculator
With a mean of 12, a mode of 10 and a standard deviation of 4, Pearson's mode skewness is 0.5, a right-skewed shape.
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Regression intercept calculator
For x of 1 to 5 with y values 2, 4, 5, 4 and 5, the least-squares line crosses the y axis at 2.2. Enter paired x and y lists of the same length to get the…
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Sample covariance calculator
For x values 2, 4, 6, 8 and y values 1, 3, 5, 7, the cross-deviations add up to 20 and are divided by 3, a positive covariance: the two series rise together.
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Scott's rule bin width calculator
For the eight values 2, 4, 4, 4, 5, 5, 7, 9, Scott's rule gives a bin width that covers their range of 7 in 2 bins.
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Concordance correlation coefficient calculator
Two identical series from 1 to 5 give a concordance coefficient of 1, but shift or rescale one of them and it drops below 1 while Pearson's r stays at 1.
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Cubic regression calculator
Enter five points that lie on a cubic and you get its coefficients back exactly: 1, 2, −1 and 1 for the constant, linear, quadratic and cubic terms.
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Line of best fit calculator
Draw a straight trend line through paired data: for x of 1 to 5 and y of 2, 4, 5, 4 and 5, the least-squares line has slope 0.6 and intercept 2.2, with a…
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Mean Absolute Percentage Error (MAPE) Calculator
Four forecasts that miss their actual values by 10%, 5%, 10% and 10% give a MAPE of 8.75%: the average size of the miss as a percentage, with misses above and…
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Partial correlation calculator
If x and y correlate at 0.8, x and z at 0.5 and y and z at 0.4, the partial correlation of x and y controlling for z is about 0.76: most of their link survives…
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Power regression calculator
The points (1, 3), (2, 12), (4, 48) and (8, 192) follow the power curve 3·x² exactly: a is 3, b is 2 and the log-space R² is 1.
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Standard error of the estimate
For x from 1 to 5 and y of 2, 4, 5, 4, 5, the best-fit line has slope 0.6 and intercept 2.2, the squared residuals add up to 2.4, and the standard error of the…
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At least one event probability calculator
With a 0.2 chance on each trial and 5 trials, the chance of at least one success is 0.67232. You also see the chance of no success at all, so you can check that…
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Coin toss streak probability calculator
In 10 fair tosses, the chance of seeing at least one run of 3 heads in a row is 0.5078125, just over half.
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Complement probability calculator
An event with a probability of 0.35 has a complement of 0.65, the chance it does not happen. Enter any probability from 0 to 1 to get both sides as decimals and…
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Expected payoff calculator for games and gambles
A 10 % chance to win 100 adds 10 to the average, while a 50 % chance to lose 10 takes away 5. Enter every result with its probability and see the long-run…
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Lottery jackpot odds calculator
See how unlikely the top prize really is: a 6-from-49 game has 13,983,816 possible tickets, so matching every number is 1 in 13,983,816, or about 13,983,815 to…
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Marginal probability calculator
For the joint table 0.1, 0.2, 0.3, 0.4, the row marginal is 0.3 and 0.7 and the column marginal is 0.4 and 0.6.
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Mutually Exclusive Events Checker
With P(A) of 0.35, P(B) of 0.4 and a joint probability P(A and B) of 0, the two events are mutually exclusive: they cannot happen in the same outcome.
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Binomial Mean and Variance Calculator
With 20 trials and a 0.35 chance of success on each, a binomial count averages 7 successes with a variance of 4.55.
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Expected value of a dice roll
Two six-sided dice average a total of 7, with possible sums running from 2 to 12. Enter how many dice and how many sides, and get the expected total, the mean…
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Geometric CDF calculator
See how likely the first success is to arrive in time: with a 0.25 chance per attempt, at least one success within 4 attempts has probability 0.68359375, and…
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Poisson at least probability calculator
With an average of 2.5 events per interval, the chance of at least 3 is 0.4561868841166705. Enter the average rate and the minimum count you care about to get…
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Poisson PMF calculator
Exactly 3 events when 2.5 are expected on average has a probability of 0.21376301724973648. Type the rate and the count you care about to isolate that single…
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Probability of Neither Event Calculator
There is a 0.4 chance that neither A nor B happens when P(A) is 0.4, P(B) is 0.3 and their overlap is 0.1.
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Two-stage probability tree calculator
If rain has a probability of 0.3 and being late given rain 0.4, the rain-then-late path has a probability of 0.12.
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Discrete RV standard deviation
A fair die, with the values 1 to 6 at probability 1/6 each, has a mean of 3.5. Enter your own table of values and probabilities, which must add up to one, and…
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