Free IPv4 subnet calculator
Enter an IPv4 address with a CIDR prefix or a subnet mask and get the network address, broadcast address, usable host range, wildcard mask and binary view instantly. It runs in your browser and nothing is sent anywhere.
Use 192.168.10.77/26 or 192.168.10.77 255.255.255.192. Results update as you type.
- Network address
- 192.168.10.64
- Broadcast address
- 192.168.10.127
- Subnet mask
- 255.255.255.192
- Wildcard mask
- 0.0.0.63
- CIDR notation
- 192.168.10.64/26
- First usable host
- 192.168.10.65
- Last usable host
- 192.168.10.126
- Total addresses
- 64
- Usable hosts
- 62
- Address class
- C
- Address type
- private
Binary view
IP address11000000.10101000.00001010.01001101
Subnet mask11111111.11111111.11111111.11000000
Network11000000.10101000.00001010.01000000
What each result means
- Network address
- The first address in the subnet, with all host bits set to 0. It identifies the subnet and cannot be assigned to a host (except in a /31 or /32).
- Broadcast address
- The last address in the subnet, with all host bits set to 1. A packet sent here reaches every host in the subnet.
- Subnet mask
- Marks which bits are the network portion (1s) and which are the host portion (0s). A /26 mask is 255.255.255.192.
- Wildcard mask
- The inverse of the subnet mask. Cisco access lists and OSPF network statements use it. The wildcard for 255.255.255.192 is 0.0.0.63.
- Usable hosts
- Total addresses minus the network and broadcast addresses: 2^(32 - prefix) - 2. A /26 has 64 addresses and 62 usable hosts.
- Address type
- Whether the address is private (RFC 1918), public, loopback, link-local (APIPA), shared CGNAT space, multicast or reserved.
Learn to subnet without a calculator
CompTIA Network+ and A+ expect you to subnet by hand. Use the block-size method in the subnetting cheat sheet, then train with unlimited random problems in the subnetting practice tool and check your answers here.
Subnet calculator questions
- How do I calculate the network address from an IP address and mask?
- Write the IP address and the subnet mask in binary and apply a bitwise AND. The result is the network address. For 192.168.10.77 with mask 255.255.255.192, the last octet is 77 AND 192 = 64, so the network address is 192.168.10.64.
- How many usable hosts are in a /24?
- A /24 has 256 addresses and 254 usable hosts, because the network address and the broadcast address cannot be assigned to hosts.
- What is the difference between a subnet mask and CIDR notation?
- They describe the same thing. The mask 255.255.255.0 and the prefix /24 both mean that the first 24 bits are the network portion. CIDR notation is the shorter form and is what most modern networks and exams use.
- Why does a /31 have two usable addresses?
- RFC 3021 allows /31 subnets on point-to-point links, so both addresses can be assigned to the two ends and no network or broadcast address is needed. A /32 identifies a single host.
- Can I use this to prepare for the Network+ or A+ exam?
- Use it to check your work, not to replace the skill. Plan to subnet by hand on exam day, so practice the block-size method with the subnetting practice tool and then verify your answers here.