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Subnet Calculator
Number of usable hosts
Runs locally in your browser
Parameters
Results
- Hosts
- 254
How it works
Calculate the number of usable host addresses in an IPv4 subnet from a CIDR prefix.
Who it's for: Network administrators and IT students planning IP address allocation.
Formula: hosts = 2^(32 − CIDR) − 2, subtracting network and broadcast addresses.
Works for standard /8 through /32 prefixes.
Uses binary (1024-based) addressing conventions.
How to use
- Enter CIDR prefix length from 1 to 32 (e.g., 24 for a /24 subnet).
- Read Hosts for the number of assignable device addresses.
Good to know
- /31 and /32 are special cases for point-to-point links — this calculator subtracts 2 addresses as usual.