Calc allows you to calculate values using mathematical expressions with addition +, subtraction -, multiplication *, division /. You can combine values with different unit values such as em, px or %.
You can use calc where ever length, angle, frequency, time or numbers are used.
The result must be within the allowable range for the property.
Space is required around plus + and minus - symbols.

Great potential for calculating widths in layouts where one value is fixed and others are unknown.

Live Example
Play with the code in the textarea below.

Introduced in CSS version
Applies to elements
where length, angle, frequency, time or numbers are used
Browser Support
Versions9-moz- 8-webkit- 5.2-webkit- 19
Belongs to:

See the full list CSS properties and browser support: CSS Properties