networkDifficulty: 3/5
Subnet Calculator
Calculate subnet details from an IP address plus a mask or prefix. Shows network, broadcast, mask, wildcard, host range and host count, all client-side.
255.255.255.0, /24 or 24 all work
How it works
- Enter an IPv4 address, then a subnet mask (255.255.255.0) or a prefix (/24 or 24).
- Press Calculate for the network, broadcast, masks, host range and host count.
- Non-contiguous masks such as 255.0.255.0 are rejected as invalid.
Frequently Asked Questions
Can I enter a dotted mask instead of a prefix?
Yes. Both 255.255.255.0 and /24 are accepted, and non-contiguous masks such as 255.0.255.0 are correctly rejected as invalid.
How is this different from the CIDR calculator?
It is the same maths with a different entry point: this one takes an address plus a mask, the CIDR calculator takes a single slash notation block.
Are private ranges identified?
Yes. RFC 1918 private ranges, loopback and link-local addresses are flagged.