Work out network, broadcast, usable host range and masks for any IPv4 subnet.
🔒 Calculated in your browser.
How to use the ip subnet calculator
- Enter an IP with a prefix like /24, or a subnet mask.
- Read the network and host range.
- Copy what you need into your router or firewall.
CIDR cheat sheet
/24 = 254 hosts (255.255.255.0), /25 = 126, /26 = 62, /27 = 30, /28 = 14, /29 = 6, /30 = 2, /16 = 65,534.
Frequently asked questions
What is CIDR?
A way of writing a subnet as address/prefix, where the prefix is the number of network bits.
Why are 2 addresses unusable?
The network and broadcast addresses can't be assigned to hosts (except /31 and /32).
Does it support IPv6?
IPv4 only for now.