IP Subnet Calculator (CIDR)
Calculate network address, broadcast, netmask, host range, and host count from any IPv4 CIDR block.
| Network address | 192.168.1.0/24 |
| Netmask | 255.255.255.0 |
| Wildcard mask | 0.0.0.255 |
| Broadcast address | 192.168.1.255 |
| First usable host | 192.168.1.1 |
| Last usable host | 192.168.1.254 |
| Total addresses | 256 |
| Usable hosts | 254 |
| Mask bits | /24 |
/31 and /32 are treated per RFC 3021 (point-to-point and single host). All math runs in your browser.
About IP Subnet Calculator (CIDR)
Enter an IPv4 address with a CIDR prefix (e.g. 192.168.1.0/24) and instantly see the network address, netmask, wildcard mask, broadcast address, first and last usable host, total addresses, and usable host count. Handles /31 and /32 per RFC 3021. All math runs in your browser.
All processing happens entirely in your browser using modern web APIs. Nothing is uploaded to our servers — your data stays local and private. Free to use forever.
Common use cases
- Planning subnets and address ranges for a network
- Finding the usable host range for a given CIDR block
- Converting between CIDR prefix and dotted-decimal netmask
- Determining the broadcast address for a subnet
- Checking how many hosts a /26 or /27 supports
How it works
The IP is parsed into a 32-bit unsigned integer and the prefix length builds a bitmask. Bitwise AND with the mask gives the network address; OR with the inverted mask gives the broadcast. The usable host range is network+1 to broadcast-1 (with /31 and /32 handled as special point-to-point and single-host cases per RFC 3021). Host counts are 2^(32 − prefix).