# of Subnet ID Bit

# of Host ID Bits

# of Subnets Per Network

# of
Hosts Per Subnet

Subnet Mask

(Binary / Dotted Decimal)

Subnet Mask (Slash/ CIDR Notation)

Subnet Address #N Formula (N=0, 1, … # of Subnets-1)

0 (Default)

16

1

65,534

11111111.11111111.00000000.00000000

255.255.0.0

/16

--

1

15

2

32,766

11111111.11111111.10000000.00000000

255.255.128.0

/17

x.y.N*128.0

2

14

4

16,382

11111111.11111111.11000000.00000000

255.255.192.0

/18

x.y.N*64.0

3

13

8

8,190

11111111.11111111.11100000.00000000

255.255.224.0

/19

x.y.N*32.0

4

12

16

4,094

11111111.11111111.11110000.00000000

255.255.240.0

/20

x.y.N*16.0

5

11

32

2,046

11111111.11111111.11111000.00000000

255.255.248.0

/21

x.y.N*8.0

6

10

64

1,022

11111111.11111111.11111100.00000000

255.255.252.0

/22

x.y.N*4.0

7

9

128

510

11111111.11111111.11111110.00000000

255.255.254.0

/23

x.y.N*2.0

8

8

256

254

11111111.11111111.11111111.00000000

255.255.255.0

/24

x.y.N.0

9

7

512

126

11111111.11111111.11111111.10000000

255.255.255.128

/25

x.y.N/2.

(N%2)*128

10

6

1,024

62

11111111.11111111.11111111.11000000

255.255.255.192

/26

x.y.N/4.

(N%4)*64

11

5

2,048

30

11111111.11111111.11111111.11100000

255.255.255.224

/27

x.x.N/8.

(N%8)*32

12

4

4,096

14

11111111.11111111.11111111.11110000

255.255.255.240

/28

x.y.N/16.

(N%16)*16

13

3

8,192

6

11111111.11111111.11111111.11111000

255.255.255.248

/29

x.y.N/32.

(N%32)*8

14

2

16,384

2

11111111.11111111.11111111.11111100

255.255.255.252

/30

x.y.N/64.

(N%64)*4