IP Subnet Calculator
Type an address with a prefix such as 10.0.0.5/20, or pick a mask, and read off the network, broadcast, host range and mask in dotted and binary form.
- Network address
- 192.168.1.0/24
- Subnet mask
- 255.255.255.0
- Wildcard mask
- 0.0.0.255
- Broadcast address
- 192.168.1.255
- Usable host range
- 192.168.1.1 – 192.168.1.254
- Usable hosts
- 254
- Total addresses
- 256
- Class
- C
- Address type
- Private (RFC 1918)
- Binary address
- 11000000.10101000.00000001.00000000
- Binary mask
- 11111111.11111111.11111111.00000000
About this tool
An IPv4 address is 32 bits; the prefix length after the slash says how many of them identify the network. A /24 leaves 8 bits for hosts, giving 256 addresses of which the first (network) and last (broadcast) are reserved, so 254 are usable. The subnet mask is the same idea written as four octets, 255.255.255.0 for /24, and the wildcard mask is its inverse, used in Cisco access lists.
The calculator also classifies the address: private ranges (10/8, 172.16/12, 192.168/16) are for internal networks, 100.64/10 is carrier-grade NAT, 127/8 is loopback, 169.254/16 is link-local, and 224/4 is multicast. Point-to-point links can use /31 with both addresses usable (RFC 3021), and /32 denotes a single host.
Frequently asked questions
- How many usable hosts does a /26 have?
- 62. A /26 has 64 addresses; the network and broadcast addresses are reserved.
- What is a wildcard mask?
- The bitwise inverse of the subnet mask, for example 0.0.0.255 for /24. Cisco ACLs and OSPF configuration use it instead of the netmask.
- Why are /31 and /32 different?
- A /32 is a single address, used for loopbacks and host routes. A /31 has two addresses and, on point-to-point links, both can be assigned.
- Does it support IPv6?
- Not yet. This calculator covers IPv4.