Free online calculators

Simple, accurate tools for everyday math. Enter your numbers, get a clear answer, and see how it was worked out.

Date CalculatorDays between two dates, or add and subtract days, weeks, months and years. GPA CalculatorSemester and cumulative GPA on the standard 4.0 scale. Final Grade CalculatorFind the score you need on your final exam. Percentage CalculatorPercent of a number, percent change, increase and decrease.

How Calcu works

Every calculator runs in your browser, so the numbers you type are not sent anywhere. Each page explains the formula behind the result, gives a worked example, and answers common questions, so you can check the math yourself.

More calculators are on the way. If a result looks wrong, the formula shown on each page is the best place to start checking.