IP Subnet Table

Class A

Number of bits borrowed	Number of usable subnets	Number of usable IPs	Subnet Mask
2	4	4mt	255.192.0.0
3	8	2mt	255.224.0.0
4	16	1mt	255.240.0.0
5	32	524t	255.248.0.0
6	64	262t	255.252.0.0
7	128	131t	255.254.0.0
8	256	65,536	255.255.0.0

Class B

Number of bits borrowed	Number of usable subnets	Number of usable IPs	Subnet Mask
2	4	16,380	255.255.192.0
3	8	8,190	255.255.224.0
4	16	4,094	255.255.240.0
5	32	2,046	255.255.248.0
6	64	1,022	255.255.252.0
7	128	510	255.255.254.0
8	256	254	255.255.255.0

Class C

Number of bits borrowed	Number of usable subnets	Number of usable IPs	Subnet Mask
2	4	60	255.255.255.192
3	8	30	255.255.255.224
4	16	14	255.255.255.240
5	32	6	255.255.255.248
6	64	2	255.255.255.252