Subnet Calculator
Address:
.
.
.
/
Mask:
.
.
.
Binary:
11111111111111111111111100000000
Reverse:
.
.
.
Binary:
00000000000000000000000011111111
Hex:
.
.
.
Net/Bcast:
192.168.1.0
-
192.168.1.255
(
256
addresses )
Reverse Hex:
.
.
.
Usable:
192.168.1.1
-
192.168.1.254
(
254
addresses )
Tips:
Wikipedia on Subnetting
Cisco on Subnetting