Updated: 01/18/2023 by Computer Hope

Prime may refer to any of the following:

1. When referring to a service or product, Prime is short for Amazon Prime.

2. When referring to a number, prime is short for a prime number.

3. With a mark or a symbol, a single prime symbol is often used to represent the ft (feet) measurement, and a double prime represents inches. For example, if someone said they're 5′ 9″, it's the same as saying they're five feet nine inches. If the prime symbol is unavailable it's often substituted with a single quote and quote.

Where are the prime and double prime keys on the keyboard?

These characters do not have dedicated keys on the keyboard and must be added through the operating system's special characters functionality.

If you are using Microsoft Windows, you can use the Character Map utility to insert special characters not available on the keyboard.

If you are using macOS, press Alt/Option+E to get single prime (′). Press Shift+Option+G to get double prime (″). You can also use the Character Viewer. To launch the Character Viewer, type Command+Control+Space. If you only see emoji, click the palette icon in the upper-right corner. Search for "prime".


In HTML, to insert a single prime, use the HTML entity ′. To insert a double prime, use a capital P (″).

4. Alternatively called PR1ME, Prime Computer was the name of a computer company. See our Prime Computer company page for further information on this company.