Free combination and permutation calculator — enter n and r to calculate C(n,r) or P(n,r) with step-by-step factorial work shown.

Free compound interest calculator — enter principal, rate, time, and compounding frequency to calculate future value with step-by-step formula work.

Free inverse trig calculator — enter a value and find arcsin, arccos, or arctan in degrees and radians. Identifies exact unit-circle values with step-by-step work.

Free perpendicular slope calculator — enter a slope or two points and get the perpendicular (negative reciprocal) and parallel slopes with step-by-step work.

Free quadratic formula calculator — enter a, b, c and get the solutions, discriminant, vertex, and step-by-step work for any quadratic equation ax² + bx + c = 0.

Free square root simplifier — enter any number and get the simplified radical form with step-by-step prime factorization work shown.

Free standard deviation calculator — enter your data set and get the mean, variance, population and sample standard deviation with step-by-step work shown.