Free tool
IPv4 subnet / CIDR calculator
Free IPv4 subnet / CIDR calculator: network, broadcast, netmask, wildcard, and usable host range — runs offline in your browser.
- CIDR
- 192.168.1.0/24
- Netmask
- 255.255.255.0
- Wildcard
- 0.0.0.255
- Network
- 192.168.1.0
- Broadcast
- 192.168.1.255
- Usable range
- 192.168.1.1 – 192.168.1.254
- Usable hosts
- 254
The IPv4 subnet / CIDR calculator runs entirely in your browser. Enter an address and prefix length to get network address, broadcast, wildcard mask, and usable host range — no API and no data leaves your device.
How to calculate a subnet
Provide an IPv4 address and CIDR prefix (for example 24 for 255.255.255.0). The tool derives the network block, broadcast address, and the first/last usable hosts for that prefix. Ideal for planning VLANs, VPN pools, or cloud VPC ranges.
CIDR quick reference
Smaller prefixes (larger number after the slash) mean fewer hosts. /24 is 256 addresses (254 usable on typical Ethernet). /32 is a single host. /16 is a much larger private campus range.
- Network address — first address of the block
- Broadcast — last address; not assigned to hosts on Ethernet
- Wildcard mask — inverted subnet mask used in some ACLs
IPv6 note
This calculator targets IPv4. IPv6 subnetting uses different conventions (typically /64 LANs). Use a dedicated IPv6 planner for those designs.