Subnet Calculator
Work out the network, broadcast, host range, and masks for any IPv4 address and prefix.
[local] Runs in your browser. Nothing you enter leaves your device.
- Network address
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- Broadcast address
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- Usable host range
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- Usable hosts
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- Total addresses
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- Subnet mask
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- Wildcard mask
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- CIDR notation
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- Class
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- Address type
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- Address (binary)
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- Mask (binary)
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How it works
An IPv4 address is a 32-bit number, usually written as four 8-bit numbers ("octets") like
192.168.1.10. The prefix (the /24) says how many of
those 32 bits identify the network, and the rest identify a single
host on that network.
The subnet mask is the same idea written as an address: 24 ones followed by 8
zeros is 255.255.255.0. The calculator then uses two bitwise operations:
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Network address = address
ANDmask: keep the network bits, set the host bits to 0. -
Broadcast address = network
OR(NOTmask): set every host bit to 1.
Everything in between can be given to devices, so a /24 has 28 = 256 addresses and 254 usable hosts. Two exceptions: a /31 is used for point-to-point links where both addresses are usable (RFC 3021), and a /32 is a single host.
The wildcard mask is the mask flipped (0.0.0.255 for a /24).
Cisco ACLs and OSPF use it.
Tip: link straight to a result by adding ?q= to the address, like
this example for 10.0.0.130/26