Type an IP address with a prefix like /24, or with a mask like 255.255.255.0, and get the full subnet: network and broadcast address, usable host range, number of hosts, wildcard mask, class and whether it is private or public.
loading toolHow to calculate a subnet
- Type an address with /prefix (192.168.1.10/24) or with a mask.
- Put several on separate lines to work out many at once.
- Copy or download the details.
Good to know
- 10.x, 172.16–31.x and 192.168.x are private ranges for home and office networks.
- 100.64–127.x is carrier-grade NAT: your ISP shares one public address among many customers.
Questions
How many hosts are in a /24?
256 addresses, of which 254 can be used by devices. The first is the network address and the last the broadcast address.
What about /31 and /32?
A /32 is a single address (often a server or route). A /31 has two addresses, both usable, for point-to-point links between routers.
What is a wildcard mask?
The mask flipped: 255.255.255.0 becomes 0.0.0.255. Cisco access lists and OSPF use it.
Is my data private?
Yes. Everything happens inside your own browser: nothing you type or choose is uploaded to us or anyone else.
Is it free?
Completely free, with no sign-up, no watermark and no limit on how many times you use it. Light ads keep the site running.
