Math & Conversion Calculators
Percentages and unit conversions with documented factors.
Percentage Calculator
Free percentage calculator: find X% of a number, what percent one number is of another, and percentage change — instantly in your browser.
Unit Converter
Convert length, weight, volume, area, speed, temperature, and data units using exact international definitions — factors documented on the page.
Fuel Economy Calculator
Free fuel-economy calculator: convert L/100km to US MPG and back, and estimate the fuel and cost of any trip from distance, consumption, and price per liter.
GPA Calculator
Free GPA calculator: enter up to six courses with grade points and credits and get your weighted GPA on your own scale — 4.0, 5.0, or 20-point — instantly in your browser.
Percentage Change Calculator
Free percentage change calculator: enter an old value and a new value to get the percent increase or decrease and the absolute change, rounded for display.