Subnet calculator
Enter an IPv4 or IPv6 address with prefix or netmask: network, range and number of hosts appear immediately.
Runs only in your browser.
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Result
e.g. 192.168.10.25/24, 10.0.0.1 255.255.255.0 or 2001:db8::1/48
Split network
| Network | First | Last | Broadcast | Addresses |
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Frequently asked questions
Why does a /31 have two usable addresses?
Point-to-point links need neither a network nor a broadcast address (RFC 3021). Both addresses of a /31 are therefore usable; a /32 denotes exactly one address.
What is the wildcard mask?
The inverted netmask, i.e. 0.0.0.255 instead of 255.255.255.0. Access lists and OSPF on Cisco devices expect it in this form.
Are my addresses sent?
No. The calculator runs in your browser, the addresses you enter never leave your device.
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