CIDR / Subnet Calculator
Calculate subnet range, mask, and host counts from CIDR.
Enter an IPv4 address in CIDR notation to instantly get the network and broadcast addresses, usable host range, netmask, wildcard mask, and total and usable host counts. Everything is computed locally in your browser.
Runs entirely in your browser — nothing is uploaded.
How to use the cidr / subnet calculator
- 1Type an address and prefix, e.g. 192.168.1.10/24.
- 2Read the network, broadcast, and host range.
- 3Copy the values you need.
Frequently asked questions
What does the /24 mean?
The number after the slash is the prefix length — how many leading bits are the network portion. /24 means a 255.255.255.0 mask with 254 usable hosts.
Does it handle /31 and /32?
Yes — /31 is treated as a 2-address point-to-point link and /32 as a single host, per common practice.