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IP subnet calculator

Type an address with its prefix or mask to see the network, its usable range and masks. Split it into smaller subnets, or look up any prefix in the reference tables.

Network23.0.0.0/10
Usable hosts4,194,302
Subnet mask255.192.0.0
Addresses4,194,304
Network address
23.0.0.0
Broadcast address
23.63.255.255
First usable
23.0.0.1
Last usable
23.63.255.254
Usable hosts
4,194,302 (4,194,304 less the network and broadcast addresses)
Subnet mask
255.192.0.0
Wildcard mask
0.63.255.255 (Cisco ACLs, OSPF)
Prefix length
/10
Type
Public public
Old class
A (default /8)
As numbers
Hex 17000000 · Integer 385875968 to 390070271
Reverse DNS zones
0.23.in-addr.arpa
1.23.in-addr.arpa
2.23.in-addr.arpa
3.23.in-addr.arpa
4.23.in-addr.arpa
5.23.in-addr.arpa
6.23.in-addr.arpa
7.23.in-addr.arpa
8.23.in-addr.arpa
9.23.in-addr.arpa
10.23.in-addr.arpa
11.23.in-addr.arpa
12.23.in-addr.arpa
13.23.in-addr.arpa
14.23.in-addr.arpa
15.23.in-addr.arpa
and 48 more
/10 is not on a 8-bit boundary, so it takes 64 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00010111.00000000.00000000.0000000023.0.0.0
Subnet mask11111111.11000000.00000000.00000000255.192.0.0
Network00010111.00000000.00000000.0000000023.0.0.0
Broadcast00010111.00111111.11111111.1111111123.63.255.255
Split into smaller subnets/22
/11 (2)/12 (4)/13 (8)/14 (16)/15 (32)/16 (64)/17 (128)/18 (256)/19 (512)/20 (1,024)/21 (2,048)/22 (4,096)

23.0.0.0/10 makes 4,096 subnets of /22; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
123.0.0.0/2223.0.0.1 to 23.0.3.25423.0.3.2551,022
223.0.4.0/2223.0.4.1 to 23.0.7.25423.0.7.2551,022
323.0.8.0/2223.0.8.1 to 23.0.11.25423.0.11.2551,022
423.0.12.0/2223.0.12.1 to 23.0.15.25423.0.15.2551,022
523.0.16.0/2223.0.16.1 to 23.0.19.25423.0.19.2551,022
623.0.20.0/2223.0.20.1 to 23.0.23.25423.0.23.2551,022
723.0.24.0/2223.0.24.1 to 23.0.27.25423.0.27.2551,022
823.0.28.0/2223.0.28.1 to 23.0.31.25423.0.31.2551,022
923.0.32.0/2223.0.32.1 to 23.0.35.25423.0.35.2551,022
1023.0.36.0/2223.0.36.1 to 23.0.39.25423.0.39.2551,022
1123.0.40.0/2223.0.40.1 to 23.0.43.25423.0.43.2551,022
1223.0.44.0/2223.0.44.1 to 23.0.47.25423.0.47.2551,022
1323.0.48.0/2223.0.48.1 to 23.0.51.25423.0.51.2551,022
1423.0.52.0/2223.0.52.1 to 23.0.55.25423.0.55.2551,022
1523.0.56.0/2223.0.56.1 to 23.0.59.25423.0.59.2551,022
1623.0.60.0/2223.0.60.1 to 23.0.63.25423.0.63.2551,022
1723.0.64.0/2223.0.64.1 to 23.0.67.25423.0.67.2551,022
1823.0.68.0/2223.0.68.1 to 23.0.71.25423.0.71.2551,022
1923.0.72.0/2223.0.72.1 to 23.0.75.25423.0.75.2551,022
2023.0.76.0/2223.0.76.1 to 23.0.79.25423.0.79.2551,022
2123.0.80.0/2223.0.80.1 to 23.0.83.25423.0.83.2551,022
2223.0.84.0/2223.0.84.1 to 23.0.87.25423.0.87.2551,022
2323.0.88.0/2223.0.88.1 to 23.0.91.25423.0.91.2551,022
2423.0.92.0/2223.0.92.1 to 23.0.95.25423.0.95.2551,022
2523.0.96.0/2223.0.96.1 to 23.0.99.25423.0.99.2551,022
2623.0.100.0/2223.0.100.1 to 23.0.103.25423.0.103.2551,022
2723.0.104.0/2223.0.104.1 to 23.0.107.25423.0.107.2551,022
2823.0.108.0/2223.0.108.1 to 23.0.111.25423.0.111.2551,022
2923.0.112.0/2223.0.112.1 to 23.0.115.25423.0.115.2551,022
3023.0.116.0/2223.0.116.1 to 23.0.119.25423.0.119.2551,022
3123.0.120.0/2223.0.120.1 to 23.0.123.25423.0.123.2551,022
3223.0.124.0/2223.0.124.1 to 23.0.127.25423.0.127.2551,022
3323.0.128.0/2223.0.128.1 to 23.0.131.25423.0.131.2551,022
3423.0.132.0/2223.0.132.1 to 23.0.135.25423.0.135.2551,022
3523.0.136.0/2223.0.136.1 to 23.0.139.25423.0.139.2551,022
3623.0.140.0/2223.0.140.1 to 23.0.143.25423.0.143.2551,022
3723.0.144.0/2223.0.144.1 to 23.0.147.25423.0.147.2551,022
3823.0.148.0/2223.0.148.1 to 23.0.151.25423.0.151.2551,022
3923.0.152.0/2223.0.152.1 to 23.0.155.25423.0.155.2551,022
4023.0.156.0/2223.0.156.1 to 23.0.159.25423.0.159.2551,022
4123.0.160.0/2223.0.160.1 to 23.0.163.25423.0.163.2551,022
4223.0.164.0/2223.0.164.1 to 23.0.167.25423.0.167.2551,022
4323.0.168.0/2223.0.168.1 to 23.0.171.25423.0.171.2551,022
4423.0.172.0/2223.0.172.1 to 23.0.175.25423.0.175.2551,022
4523.0.176.0/2223.0.176.1 to 23.0.179.25423.0.179.2551,022
4623.0.180.0/2223.0.180.1 to 23.0.183.25423.0.183.2551,022
4723.0.184.0/2223.0.184.1 to 23.0.187.25423.0.187.2551,022
4823.0.188.0/2223.0.188.1 to 23.0.191.25423.0.191.2551,022
4923.0.192.0/2223.0.192.1 to 23.0.195.25423.0.195.2551,022
5023.0.196.0/2223.0.196.1 to 23.0.199.25423.0.199.2551,022
5123.0.200.0/2223.0.200.1 to 23.0.203.25423.0.203.2551,022
5223.0.204.0/2223.0.204.1 to 23.0.207.25423.0.207.2551,022
5323.0.208.0/2223.0.208.1 to 23.0.211.25423.0.211.2551,022
5423.0.212.0/2223.0.212.1 to 23.0.215.25423.0.215.2551,022
5523.0.216.0/2223.0.216.1 to 23.0.219.25423.0.219.2551,022
5623.0.220.0/2223.0.220.1 to 23.0.223.25423.0.223.2551,022
5723.0.224.0/2223.0.224.1 to 23.0.227.25423.0.227.2551,022
5823.0.228.0/2223.0.228.1 to 23.0.231.25423.0.231.2551,022
5923.0.232.0/2223.0.232.1 to 23.0.235.25423.0.235.2551,022
6023.0.236.0/2223.0.236.1 to 23.0.239.25423.0.239.2551,022
6123.0.240.0/2223.0.240.1 to 23.0.243.25423.0.243.2551,022
6223.0.244.0/2223.0.244.1 to 23.0.247.25423.0.247.2551,022
6323.0.248.0/2223.0.248.1 to 23.0.251.25423.0.251.2551,022
6423.0.252.0/2223.0.252.1 to 23.0.255.25423.0.255.2551,022
6523.1.0.0/2223.1.0.1 to 23.1.3.25423.1.3.2551,022
6623.1.4.0/2223.1.4.1 to 23.1.7.25423.1.7.2551,022
6723.1.8.0/2223.1.8.1 to 23.1.11.25423.1.11.2551,022
6823.1.12.0/2223.1.12.1 to 23.1.15.25423.1.15.2551,022
6923.1.16.0/2223.1.16.1 to 23.1.19.25423.1.19.2551,022
7023.1.20.0/2223.1.20.1 to 23.1.23.25423.1.23.2551,022
7123.1.24.0/2223.1.24.1 to 23.1.27.25423.1.27.2551,022
7223.1.28.0/2223.1.28.1 to 23.1.31.25423.1.31.2551,022
7323.1.32.0/2223.1.32.1 to 23.1.35.25423.1.35.2551,022
7423.1.36.0/2223.1.36.1 to 23.1.39.25423.1.39.2551,022
7523.1.40.0/2223.1.40.1 to 23.1.43.25423.1.43.2551,022
7623.1.44.0/2223.1.44.1 to 23.1.47.25423.1.47.2551,022
7723.1.48.0/2223.1.48.1 to 23.1.51.25423.1.51.2551,022
7823.1.52.0/2223.1.52.1 to 23.1.55.25423.1.55.2551,022
7923.1.56.0/2223.1.56.1 to 23.1.59.25423.1.59.2551,022
8023.1.60.0/2223.1.60.1 to 23.1.63.25423.1.63.2551,022
8123.1.64.0/2223.1.64.1 to 23.1.67.25423.1.67.2551,022
8223.1.68.0/2223.1.68.1 to 23.1.71.25423.1.71.2551,022
8323.1.72.0/2223.1.72.1 to 23.1.75.25423.1.75.2551,022
8423.1.76.0/2223.1.76.1 to 23.1.79.25423.1.79.2551,022
8523.1.80.0/2223.1.80.1 to 23.1.83.25423.1.83.2551,022
8623.1.84.0/2223.1.84.1 to 23.1.87.25423.1.87.2551,022
8723.1.88.0/2223.1.88.1 to 23.1.91.25423.1.91.2551,022
8823.1.92.0/2223.1.92.1 to 23.1.95.25423.1.95.2551,022
8923.1.96.0/2223.1.96.1 to 23.1.99.25423.1.99.2551,022
9023.1.100.0/2223.1.100.1 to 23.1.103.25423.1.103.2551,022
9123.1.104.0/2223.1.104.1 to 23.1.107.25423.1.107.2551,022
9223.1.108.0/2223.1.108.1 to 23.1.111.25423.1.111.2551,022
9323.1.112.0/2223.1.112.1 to 23.1.115.25423.1.115.2551,022
9423.1.116.0/2223.1.116.1 to 23.1.119.25423.1.119.2551,022
9523.1.120.0/2223.1.120.1 to 23.1.123.25423.1.123.2551,022
9623.1.124.0/2223.1.124.1 to 23.1.127.25423.1.127.2551,022
9723.1.128.0/2223.1.128.1 to 23.1.131.25423.1.131.2551,022
9823.1.132.0/2223.1.132.1 to 23.1.135.25423.1.135.2551,022
9923.1.136.0/2223.1.136.1 to 23.1.139.25423.1.139.2551,022
10023.1.140.0/2223.1.140.1 to 23.1.143.25423.1.143.2551,022
10123.1.144.0/2223.1.144.1 to 23.1.147.25423.1.147.2551,022
10223.1.148.0/2223.1.148.1 to 23.1.151.25423.1.151.2551,022
10323.1.152.0/2223.1.152.1 to 23.1.155.25423.1.155.2551,022
10423.1.156.0/2223.1.156.1 to 23.1.159.25423.1.159.2551,022
10523.1.160.0/2223.1.160.1 to 23.1.163.25423.1.163.2551,022
10623.1.164.0/2223.1.164.1 to 23.1.167.25423.1.167.2551,022
10723.1.168.0/2223.1.168.1 to 23.1.171.25423.1.171.2551,022
10823.1.172.0/2223.1.172.1 to 23.1.175.25423.1.175.2551,022
10923.1.176.0/2223.1.176.1 to 23.1.179.25423.1.179.2551,022
11023.1.180.0/2223.1.180.1 to 23.1.183.25423.1.183.2551,022
11123.1.184.0/2223.1.184.1 to 23.1.187.25423.1.187.2551,022
11223.1.188.0/2223.1.188.1 to 23.1.191.25423.1.191.2551,022
11323.1.192.0/2223.1.192.1 to 23.1.195.25423.1.195.2551,022
11423.1.196.0/2223.1.196.1 to 23.1.199.25423.1.199.2551,022
11523.1.200.0/2223.1.200.1 to 23.1.203.25423.1.203.2551,022
11623.1.204.0/2223.1.204.1 to 23.1.207.25423.1.207.2551,022
11723.1.208.0/2223.1.208.1 to 23.1.211.25423.1.211.2551,022
11823.1.212.0/2223.1.212.1 to 23.1.215.25423.1.215.2551,022
11923.1.216.0/2223.1.216.1 to 23.1.219.25423.1.219.2551,022
12023.1.220.0/2223.1.220.1 to 23.1.223.25423.1.223.2551,022
12123.1.224.0/2223.1.224.1 to 23.1.227.25423.1.227.2551,022
12223.1.228.0/2223.1.228.1 to 23.1.231.25423.1.231.2551,022
12323.1.232.0/2223.1.232.1 to 23.1.235.25423.1.235.2551,022
12423.1.236.0/2223.1.236.1 to 23.1.239.25423.1.239.2551,022
12523.1.240.0/2223.1.240.1 to 23.1.243.25423.1.243.2551,022
12623.1.244.0/2223.1.244.1 to 23.1.247.25423.1.247.2551,022
12723.1.248.0/2223.1.248.1 to 23.1.251.25423.1.251.2551,022
12823.1.252.0/2223.1.252.1 to 23.1.255.25423.1.255.2551,022
12923.2.0.0/2223.2.0.1 to 23.2.3.25423.2.3.2551,022
13023.2.4.0/2223.2.4.1 to 23.2.7.25423.2.7.2551,022
13123.2.8.0/2223.2.8.1 to 23.2.11.25423.2.11.2551,022
13223.2.12.0/2223.2.12.1 to 23.2.15.25423.2.15.2551,022
13323.2.16.0/2223.2.16.1 to 23.2.19.25423.2.19.2551,022
13423.2.20.0/2223.2.20.1 to 23.2.23.25423.2.23.2551,022
13523.2.24.0/2223.2.24.1 to 23.2.27.25423.2.27.2551,022
13623.2.28.0/2223.2.28.1 to 23.2.31.25423.2.31.2551,022
13723.2.32.0/2223.2.32.1 to 23.2.35.25423.2.35.2551,022
13823.2.36.0/2223.2.36.1 to 23.2.39.25423.2.39.2551,022
13923.2.40.0/2223.2.40.1 to 23.2.43.25423.2.43.2551,022
14023.2.44.0/2223.2.44.1 to 23.2.47.25423.2.47.2551,022
14123.2.48.0/2223.2.48.1 to 23.2.51.25423.2.51.2551,022
14223.2.52.0/2223.2.52.1 to 23.2.55.25423.2.55.2551,022
14323.2.56.0/2223.2.56.1 to 23.2.59.25423.2.59.2551,022
14423.2.60.0/2223.2.60.1 to 23.2.63.25423.2.63.2551,022
14523.2.64.0/2223.2.64.1 to 23.2.67.25423.2.67.2551,022
14623.2.68.0/2223.2.68.1 to 23.2.71.25423.2.71.2551,022
14723.2.72.0/2223.2.72.1 to 23.2.75.25423.2.75.2551,022
14823.2.76.0/2223.2.76.1 to 23.2.79.25423.2.79.2551,022
14923.2.80.0/2223.2.80.1 to 23.2.83.25423.2.83.2551,022
15023.2.84.0/2223.2.84.1 to 23.2.87.25423.2.87.2551,022
15123.2.88.0/2223.2.88.1 to 23.2.91.25423.2.91.2551,022
15223.2.92.0/2223.2.92.1 to 23.2.95.25423.2.95.2551,022
15323.2.96.0/2223.2.96.1 to 23.2.99.25423.2.99.2551,022
15423.2.100.0/2223.2.100.1 to 23.2.103.25423.2.103.2551,022
15523.2.104.0/2223.2.104.1 to 23.2.107.25423.2.107.2551,022
15623.2.108.0/2223.2.108.1 to 23.2.111.25423.2.111.2551,022
15723.2.112.0/2223.2.112.1 to 23.2.115.25423.2.115.2551,022
15823.2.116.0/2223.2.116.1 to 23.2.119.25423.2.119.2551,022
15923.2.120.0/2223.2.120.1 to 23.2.123.25423.2.123.2551,022
16023.2.124.0/2223.2.124.1 to 23.2.127.25423.2.127.2551,022
16123.2.128.0/2223.2.128.1 to 23.2.131.25423.2.131.2551,022
16223.2.132.0/2223.2.132.1 to 23.2.135.25423.2.135.2551,022
16323.2.136.0/2223.2.136.1 to 23.2.139.25423.2.139.2551,022
16423.2.140.0/2223.2.140.1 to 23.2.143.25423.2.143.2551,022
16523.2.144.0/2223.2.144.1 to 23.2.147.25423.2.147.2551,022
16623.2.148.0/2223.2.148.1 to 23.2.151.25423.2.151.2551,022
16723.2.152.0/2223.2.152.1 to 23.2.155.25423.2.155.2551,022
16823.2.156.0/2223.2.156.1 to 23.2.159.25423.2.159.2551,022
16923.2.160.0/2223.2.160.1 to 23.2.163.25423.2.163.2551,022
17023.2.164.0/2223.2.164.1 to 23.2.167.25423.2.167.2551,022
17123.2.168.0/2223.2.168.1 to 23.2.171.25423.2.171.2551,022
17223.2.172.0/2223.2.172.1 to 23.2.175.25423.2.175.2551,022
17323.2.176.0/2223.2.176.1 to 23.2.179.25423.2.179.2551,022
17423.2.180.0/2223.2.180.1 to 23.2.183.25423.2.183.2551,022
17523.2.184.0/2223.2.184.1 to 23.2.187.25423.2.187.2551,022
17623.2.188.0/2223.2.188.1 to 23.2.191.25423.2.191.2551,022
17723.2.192.0/2223.2.192.1 to 23.2.195.25423.2.195.2551,022
17823.2.196.0/2223.2.196.1 to 23.2.199.25423.2.199.2551,022
17923.2.200.0/2223.2.200.1 to 23.2.203.25423.2.203.2551,022
18023.2.204.0/2223.2.204.1 to 23.2.207.25423.2.207.2551,022
18123.2.208.0/2223.2.208.1 to 23.2.211.25423.2.211.2551,022
18223.2.212.0/2223.2.212.1 to 23.2.215.25423.2.215.2551,022
18323.2.216.0/2223.2.216.1 to 23.2.219.25423.2.219.2551,022
18423.2.220.0/2223.2.220.1 to 23.2.223.25423.2.223.2551,022
18523.2.224.0/2223.2.224.1 to 23.2.227.25423.2.227.2551,022
18623.2.228.0/2223.2.228.1 to 23.2.231.25423.2.231.2551,022
18723.2.232.0/2223.2.232.1 to 23.2.235.25423.2.235.2551,022
18823.2.236.0/2223.2.236.1 to 23.2.239.25423.2.239.2551,022
18923.2.240.0/2223.2.240.1 to 23.2.243.25423.2.243.2551,022
19023.2.244.0/2223.2.244.1 to 23.2.247.25423.2.247.2551,022
19123.2.248.0/2223.2.248.1 to 23.2.251.25423.2.251.2551,022
19223.2.252.0/2223.2.252.1 to 23.2.255.25423.2.255.2551,022
19323.3.0.0/2223.3.0.1 to 23.3.3.25423.3.3.2551,022
19423.3.4.0/2223.3.4.1 to 23.3.7.25423.3.7.2551,022
19523.3.8.0/2223.3.8.1 to 23.3.11.25423.3.11.2551,022
19623.3.12.0/2223.3.12.1 to 23.3.15.25423.3.15.2551,022
19723.3.16.0/2223.3.16.1 to 23.3.19.25423.3.19.2551,022
19823.3.20.0/2223.3.20.1 to 23.3.23.25423.3.23.2551,022
19923.3.24.0/2223.3.24.1 to 23.3.27.25423.3.27.2551,022
20023.3.28.0/2223.3.28.1 to 23.3.31.25423.3.31.2551,022
20123.3.32.0/2223.3.32.1 to 23.3.35.25423.3.35.2551,022
20223.3.36.0/2223.3.36.1 to 23.3.39.25423.3.39.2551,022
20323.3.40.0/2223.3.40.1 to 23.3.43.25423.3.43.2551,022
20423.3.44.0/2223.3.44.1 to 23.3.47.25423.3.47.2551,022
20523.3.48.0/2223.3.48.1 to 23.3.51.25423.3.51.2551,022
20623.3.52.0/2223.3.52.1 to 23.3.55.25423.3.55.2551,022
20723.3.56.0/2223.3.56.1 to 23.3.59.25423.3.59.2551,022
20823.3.60.0/2223.3.60.1 to 23.3.63.25423.3.63.2551,022
20923.3.64.0/2223.3.64.1 to 23.3.67.25423.3.67.2551,022
21023.3.68.0/2223.3.68.1 to 23.3.71.25423.3.71.2551,022
21123.3.72.0/2223.3.72.1 to 23.3.75.25423.3.75.2551,022
21223.3.76.0/2223.3.76.1 to 23.3.79.25423.3.79.2551,022
21323.3.80.0/2223.3.80.1 to 23.3.83.25423.3.83.2551,022
21423.3.84.0/2223.3.84.1 to 23.3.87.25423.3.87.2551,022
21523.3.88.0/2223.3.88.1 to 23.3.91.25423.3.91.2551,022
21623.3.92.0/2223.3.92.1 to 23.3.95.25423.3.95.2551,022
21723.3.96.0/2223.3.96.1 to 23.3.99.25423.3.99.2551,022
21823.3.100.0/2223.3.100.1 to 23.3.103.25423.3.103.2551,022
21923.3.104.0/2223.3.104.1 to 23.3.107.25423.3.107.2551,022
22023.3.108.0/2223.3.108.1 to 23.3.111.25423.3.111.2551,022
22123.3.112.0/2223.3.112.1 to 23.3.115.25423.3.115.2551,022
22223.3.116.0/2223.3.116.1 to 23.3.119.25423.3.119.2551,022
22323.3.120.0/2223.3.120.1 to 23.3.123.25423.3.123.2551,022
22423.3.124.0/2223.3.124.1 to 23.3.127.25423.3.127.2551,022
22523.3.128.0/2223.3.128.1 to 23.3.131.25423.3.131.2551,022
22623.3.132.0/2223.3.132.1 to 23.3.135.25423.3.135.2551,022
22723.3.136.0/2223.3.136.1 to 23.3.139.25423.3.139.2551,022
22823.3.140.0/2223.3.140.1 to 23.3.143.25423.3.143.2551,022
22923.3.144.0/2223.3.144.1 to 23.3.147.25423.3.147.2551,022
23023.3.148.0/2223.3.148.1 to 23.3.151.25423.3.151.2551,022
23123.3.152.0/2223.3.152.1 to 23.3.155.25423.3.155.2551,022
23223.3.156.0/2223.3.156.1 to 23.3.159.25423.3.159.2551,022
23323.3.160.0/2223.3.160.1 to 23.3.163.25423.3.163.2551,022
23423.3.164.0/2223.3.164.1 to 23.3.167.25423.3.167.2551,022
23523.3.168.0/2223.3.168.1 to 23.3.171.25423.3.171.2551,022
23623.3.172.0/2223.3.172.1 to 23.3.175.25423.3.175.2551,022
23723.3.176.0/2223.3.176.1 to 23.3.179.25423.3.179.2551,022
23823.3.180.0/2223.3.180.1 to 23.3.183.25423.3.183.2551,022
23923.3.184.0/2223.3.184.1 to 23.3.187.25423.3.187.2551,022
24023.3.188.0/2223.3.188.1 to 23.3.191.25423.3.191.2551,022
24123.3.192.0/2223.3.192.1 to 23.3.195.25423.3.195.2551,022
24223.3.196.0/2223.3.196.1 to 23.3.199.25423.3.199.2551,022
24323.3.200.0/2223.3.200.1 to 23.3.203.25423.3.203.2551,022
24423.3.204.0/2223.3.204.1 to 23.3.207.25423.3.207.2551,022
24523.3.208.0/2223.3.208.1 to 23.3.211.25423.3.211.2551,022
24623.3.212.0/2223.3.212.1 to 23.3.215.25423.3.215.2551,022
24723.3.216.0/2223.3.216.1 to 23.3.219.25423.3.219.2551,022
24823.3.220.0/2223.3.220.1 to 23.3.223.25423.3.223.2551,022
24923.3.224.0/2223.3.224.1 to 23.3.227.25423.3.227.2551,022
25023.3.228.0/2223.3.228.1 to 23.3.231.25423.3.231.2551,022
25123.3.232.0/2223.3.232.1 to 23.3.235.25423.3.235.2551,022
25223.3.236.0/2223.3.236.1 to 23.3.239.25423.3.239.2551,022
25323.3.240.0/2223.3.240.1 to 23.3.243.25423.3.243.2551,022
25423.3.244.0/2223.3.244.1 to 23.3.247.25423.3.247.2551,022
25523.3.248.0/2223.3.248.1 to 23.3.251.25423.3.251.2551,022
25623.3.252.0/2223.3.252.1 to 23.3.255.25423.3.255.2551,022

IPv4 CIDR reference (/0 to /32)

IPv4 prefix lengths
PrefixSubnet maskWildcardAddressesUsable hostsSizeTypical use
/00.0.0.0255.255.255.2554,294,967,2964,294,967,29416,777,216 × /24
/1128.0.0.0127.255.255.2552,147,483,6482,147,483,6468,388,608 × /24
/2192.0.0.063.255.255.2551,073,741,8241,073,741,8224,194,304 × /24
/3224.0.0.031.255.255.255536,870,912536,870,9102,097,152 × /24
/4240.0.0.015.255.255.255268,435,456268,435,4541,048,576 × /24
/5248.0.0.07.255.255.255134,217,728134,217,726524,288 × /24
/6252.0.0.03.255.255.25567,108,86467,108,862262,144 × /24
/7254.0.0.01.255.255.25533,554,43233,554,430131,072 × /24
/8255.0.0.00.255.255.25516,777,21616,777,21465,536 × /24Old class A; 10.0.0.0/8
/9255.128.0.00.127.255.2558,388,6088,388,60632,768 × /24
/10255.192.0.00.63.255.2554,194,3044,194,30216,384 × /24
/11255.224.0.00.31.255.2552,097,1522,097,1508,192 × /24
/12255.240.0.00.15.255.2551,048,5761,048,5744,096 × /24172.16.0.0/12
/13255.248.0.00.7.255.255524,288524,2862,048 × /24
/14255.252.0.00.3.255.255262,144262,1421,024 × /24
/15255.254.0.00.1.255.255131,072131,070512 × /24
/16255.255.0.00.0.255.25565,53665,534256 × /24Old class B; 192.168.0.0/16
/17255.255.128.00.0.127.25532,76832,766128 × /24
/18255.255.192.00.0.63.25516,38416,38264 × /24
/19255.255.224.00.0.31.2558,1928,19032 × /24
/20255.255.240.00.0.15.2554,0964,09416 × /24
/21255.255.248.00.0.7.2552,0482,0468 × /24
/22255.255.252.00.0.3.2551,0241,0224 × /24Large office or guest Wi-Fi (1,022 hosts)
/23255.255.254.00.0.1.2555125102 × /24Larger office LAN (510 hosts)
/24255.255.255.00.0.0.2552562541 × /24Typical office LAN (old class C)
/25255.255.255.1280.0.0.1271281261/2 of a /24Smaller LAN or VLAN
/26255.255.255.1920.0.0.6364621/4 of a /24Smaller LAN or VLAN
/27255.255.255.2240.0.0.3132301/8 of a /24Small VLAN, phones, cameras
/28255.255.255.2400.0.0.1516141/16 of a /24Small VLAN, phones, cameras
/29255.255.255.2480.0.0.7861/32 of a /24Small fixed public block (5 usable)
/30255.255.255.2520.0.0.3421/64 of a /24Point-to-point (old style)
/31255.255.255.2540.0.0.1221/128 of a /24Point-to-point link (RFC 3021)
/32255.255.255.2550.0.0.0111/256 of a /24One host

IPv6 prefix reference

IPv6 prefix lengths
PrefixAddresses/64 LANs/48 sitesNibbleTypical use
/342,535,295,865,117,307,932,921,825,928,971,026,432 (2^125)2,305,843,009,213,693,95235,184,372,088,832NoAll global unicast (2000::/3)
/165,192,296,858,534,827,628,530,496,329,220,096 (2^112)281,474,976,710,6564,294,967,296Yes
/20324,518,553,658,426,726,783,156,020,576,256 (2^108)17,592,186,044,416268,435,456YesLarge provider allocation (RIPE minimum for some)
/29633,825,300,114,114,700,748,351,602,688 (2^99)34,359,738,368524,288NoRIPE allocation to a provider (often)
/3279,228,162,514,264,337,593,543,950,336 (2^96)4,294,967,29665,536YesProvider allocation (RIPE default)
/364,951,760,157,141,521,099,596,496,896 (2^92)268,435,4564,096Yes
/40309,485,009,821,345,068,724,781,056 (2^88)16,777,216256Yes
/4419,342,813,113,834,066,795,298,816 (2^84)1,048,57616Yes
/481,208,925,819,614,629,174,706,176 (2^80)65,5361YesOne site or organisation (RIPE PI / assignment)
/5275,557,863,725,914,323,419,136 (2^76)4,096Yes
/564,722,366,482,869,645,213,696 (2^72)256YesSmall site or home (common provider assignment)
/60295,147,905,179,352,825,856 (2^68)16YesSome home broadband (16 LANs)
/6418,446,744,073,709,551,616 (2^64)1YesOne LAN or VLAN (needed for SLAAC)
/7272,057,594,037,927,936 (2^56)1/256 of a /64Yes
/80281,474,976,710,656 (2^48)1/65,536 of a /64Yes
/964,294,967,2961/4,294,967,296 of a /64YesEmbeds an IPv4 address (NAT64)
/11265,5361/281,474,976,710,656 of a /64Yes
/1202561/72,057,594,037,927,936 of a /64Yes
/124161/1,152,921,504,606,846,976 of a /64Yes
/12641/4,611,686,018,427,387,904 of a /64No
/12721/9,223,372,036,854,775,808 of a /64NoPoint-to-point link (RFC 6164)
/12811/18,446,744,073,709,551,616 of a /64YesOne host or loopback

Private and special ranges

IPv4

Special-purpose ranges
RangeNameWhat it is
255.255.255.255/32Limited broadcastEvery host on the local network
0.0.0.0/8This networkNot routed; 0.0.0.0 means "any address" in settings
10.0.0.0/8Private (RFC 1918)Office and home networks; not routed on the internet
100.64.0.0/10Shared address space (CGNAT)Used by providers behind carrier-grade NAT (RFC 6598)
127.0.0.0/8LoopbackThis computer
169.254.0.0/16Link-local (APIPA)Self-assigned when no DHCP server answers
172.16.0.0/12Private (RFC 1918)Office and home networks; not routed on the internet
192.0.0.0/24IETF protocol assignmentsSpecial uses such as DS-Lite
192.0.2.0/24Documentation (TEST-NET-1)For examples; never used on a network
192.88.99.0/246to4 relay (deprecated)Formerly anycast for 6to4
192.168.0.0/16Private (RFC 1918)Office and home networks; not routed on the internet
198.18.0.0/15BenchmarkingNetwork equipment testing (RFC 2544)
198.51.100.0/24Documentation (TEST-NET-2)For examples; never used on a network
203.0.113.0/24Documentation (TEST-NET-3)For examples; never used on a network
224.0.0.0/4MulticastOne-to-many traffic, such as IPTV and routing protocols
240.0.0.0/4ReservedFuture use; not usable on most systems

IPv6

Special-purpose ranges
RangeNameWhat it is
::/128UnspecifiedNo address; :: means "any address" in settings
::1/128LoopbackThis computer
::ffff:0:0/96IPv4-mappedAn IPv4 address written as IPv6
64:ff9b::/96NAT64IPv4 addresses reached through a NAT64 gateway
100::/64Discard onlyTraffic sent here is dropped (RFC 6666)
2001:db8::/32DocumentationFor examples; never used on a network
2001::/32TeredoIPv6 tunnelled over IPv4 UDP
2002::/166to4IPv6 tunnelled over IPv4 (largely retired)
3fff::/20DocumentationFor examples (RFC 9637)
fc00::/7Unique local (ULA)Private IPv6, like RFC 1918; usually fd00::/8
fe80::/10Link-localEvery IPv6 interface has one; not routed
ff00::/8MulticastOne-to-many traffic; replaces broadcast
2000::/3Global unicastPublic internet addresses

About this tool

A network is written as an address and a prefix length, such as 192.168.1.0/24: the first 24 bits name the network and the rest number the devices on it. The calculator works out where the network starts and ends, how many devices it holds, its subnet and wildcard masks, and the reverse DNS zone to ask your provider for.

It also splits a network into equal smaller ones (one per VLAN or site), turns a range of addresses into the fewest CIDR blocks for a firewall rule, and lists every IPv4 prefix length and the common IPv6 ones in reference tables.

Common questions

Why are two addresses lost in every IPv4 subnet?

The first address names the network and the last is the broadcast address, so a /24 has 256 addresses but 254 for devices. A /31 (a link between two routers) and a /32 (one host) are the exceptions.

What size of IPv6 network should a LAN use?

Always /64. Devices pick their own address within it (SLAAC), which needs the full 64 bits. A site usually gets a /48 or /56 from its provider, which holds 65,536 or 256 LANs.

What is a wildcard mask?

The subnet mask turned inside out: 255.255.255.0 becomes 0.0.0.255. Cisco access lists and OSPF use it to say which bits must match.

Which ranges can I use inside an office?

IPv4: 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16. IPv6: unique local addresses from fd00::/8, though most networks use the public prefix from their provider.