Netmask Calculator

Dotted quad, optionally with a /prefix suffix such as 10.0.0.1/24.
Ignored when the address already carries a /prefix, or when a mask is supplied.
Dotted-quad mask such as 255.255.255.0. Overrides the prefix length when supplied.
Number of equally sized subnets to carve out of this network. 0 to skip.
Sizes each subnet to fit at least this many usable hosts. 0 to skip.
CIDR notation
192.168.1.0/24
IPv4 Subnet Calculator
Network address
192.168.1.0
Broadcast address
192.168.1.255
First usable host
192.168.1.1
Last usable host
192.168.1.254
Subnet mask
255.255.255.0
Wildcard mask
0.0.0.255
Prefix length
24
Total addresses
256
Usable hosts
254
Traditional class
C
Address scope
private (RFC 1918)
Mask in binary
11111111.11111111.11111111.00000000
Address in binary
11000000.10101000.00000001.00001010
Address as integer
3,232,235,786
Address in hexadecimal
0xC0A8010A
Reverse DNS name
10.1.168.192.in-addr.arpa
Worked out from RFC 4632, Classless Inter-domain Routing (CIDR) and 3 other sources.

How this is worked out

4 steps
  1. Mask /24 = 255.255.255.0 (11111111.11111111.11111111.00000000)
  2. Network = address AND mask = 192.168.1.0
  3. Broadcast = network OR wildcard = 192.168.1.255
  4. Usable hosts = 2^(32-24) - 2 = 254

Results are general information, not financial, tax, legal, medical or engineering advice.