From basic arithmetic to statistics, matrices, and Ohm's law — calculators for students, engineers, and the curious.
Add, subtract, multiply, or divide fractions with a simplified result.
Find the greatest common divisor and least common multiple of numbers.
Add, subtract, or multiply matrices of any size.
Convert between binary, octal, decimal, and hexadecimal, all at once.
Spell out a number in words, international or Indian numbering.
Find voltage, current, resistance, or power from any two values.
Find a value's percentile rank, or the value at a given percentile.
Calculate nPr and nCr for any n and r.
Check if a number is prime and see its full prime factorization.
Solve ax² + bx + c = 0 for real or complex roots.
Random numbers in a range, dice rolls, and coin flips.
Convert between numbers and Roman numerals.
Find the sample size needed for a statistically representative survey.
Trigonometry, logarithms, powers, roots, and memory — all in your browser.
Mean, median, mode, range, variance, and standard deviation from a list.
Convert spelled-out numbers back into digits.
Use these tools to check homework, learn a concept or speed up a calculation. They include a scientific calculator, fraction, matrix and quadratic solvers, GCD and LCM, prime checking and factorisation, permutations and combinations, statistics, percentile and sample size calculators, number base conversion, Roman numerals, number-to-words conversion and Ohm's law.
Where possible the pages show the formula and an explanation, which helps you understand the method rather than only copying an answer. Try solving a problem by hand first and use the tool to check your result.