Compute n! for large n with exact big-integer arithmetic — no rounding errors.
n! = n × (n−1) × … × 2 × 1, with 0! = 1
5! = 5 × 4 × 3 × 2 × 1 = 120. 20! ≈ 2.43 × 10¹⁸.
Each additional factor multiplies the total by an ever-larger number, so 70! already exceeds the range of ordinary calculators. This tool switches to exact arbitrary-precision arithmetic and formats huge results in scientific notation while keeping every digit exact behind the scenes.
It makes combinatorics consistent: there is exactly one way to arrange zero items (the empty arrangement).
Counting permutations and combinations, probability, series expansions like eˣ, and recursion examples in computer science.
Full expression calculator with parentheses, powers, roots, trigonometry, logarithms and constants π and e.
Calculate X% of Y, find what percent one number is of another, and solve percentage increase problems in one place.
Find the percentage increase between an original value and a new value, including the absolute change.
Raise any base to any power, including negative and fractional exponents.
Work out how much a value dropped in percent terms, with the absolute reduction shown alongside.
Add, subtract, multiply and divide fractions and mixed numbers, with results automatically simplified.