Subnet Calculator

Calculate IPv4 network details from an address and CIDR prefix length.

How to use

Enter an IPv4 address and prefix (e.g. 24 for 255.255.255.0).

Frequently asked questions

Do you store the numbers I enter?

Calculations run in your browser. Inputs are not sent to our servers.

Are the results guaranteed accurate?

Standard formulas are used. Double-check important decisions with a professional or official source.