Free square root calculator: enter a number to get √x instantly with exact radical simplification and a rounded decimal. Supports large numbers & scientific notation. Shows steps & quick PDF.

Count significant figures and round to a set number of sig figs. Handles zeros, decimals, scientific notation, and operations (×, ÷, +, −). Instant results with rules, steps & PDF.

Find the percentage increase between two numbers. Enter original and new values to get % increase, change amount, and final value. Reverse solve from % too. Instant steps & PDF.

Free circumference calculator for circles. Enter radius or diameter to get circumference instantly. Supports multiple units and shows the formula with clear steps.