**A calculator helps people perform tasks that involve adding, multiplying, dividing or subtracting numbers.** For example, people use calculators to help them with their math homework, calculate income and expenses when filling out their tax returns, or work out how much to tip a server in a restaurant.

There are numerous types of calculators, and many people use a simple electronic calculator to perform basic arithmetic. This type of calculator typically shows the result on an LED screen and uses batteries, solar power or both.

Physicists and engineers use scientific calculators, which are much more advanced than standard calculators. These calculators have large screens that can display graphs or multiple lines of calculations. Accountants and other finance professionals also use specialized calculators, known as financial calculators, which can calculate interest on loans or savings and quickly perform currency conversions.

Many virtual calculators are available online. Generally, an online calculator has a specific purpose, such as calculating the number of calories burned during exercise, finding out the due date of a pregnancy or working out a student's estimated grade point average. When using an online calculator, users typically need to type some information into the input fields and press Calculate to view the result.