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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.

Network55.0.0.0/10
Usable hosts4,194,302
Subnet mask255.192.0.0
Addresses4,194,304
Network address
55.0.0.0
Broadcast address
55.63.255.255
First usable
55.0.0.1
Last usable
55.63.255.254
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 37000000 · Integer 922746880 to 926941183
Reverse DNS zones
0.55.in-addr.arpa
1.55.in-addr.arpa
2.55.in-addr.arpa
3.55.in-addr.arpa
4.55.in-addr.arpa
5.55.in-addr.arpa
6.55.in-addr.arpa
7.55.in-addr.arpa
8.55.in-addr.arpa
9.55.in-addr.arpa
10.55.in-addr.arpa
11.55.in-addr.arpa
12.55.in-addr.arpa
13.55.in-addr.arpa
14.55.in-addr.arpa
15.55.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
Address00110111.00000000.00000000.0000000055.0.0.0
Subnet mask11111111.11000000.00000000.00000000255.192.0.0
Network00110111.00000000.00000000.0000000055.0.0.0
Broadcast00110111.00111111.11111111.1111111155.63.255.255
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)

55.0.0.0/10 makes 4,096 subnets of /22; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
155.0.0.0/2255.0.0.1 to 55.0.3.25455.0.3.2551,022
255.0.4.0/2255.0.4.1 to 55.0.7.25455.0.7.2551,022
355.0.8.0/2255.0.8.1 to 55.0.11.25455.0.11.2551,022
455.0.12.0/2255.0.12.1 to 55.0.15.25455.0.15.2551,022
555.0.16.0/2255.0.16.1 to 55.0.19.25455.0.19.2551,022
655.0.20.0/2255.0.20.1 to 55.0.23.25455.0.23.2551,022
755.0.24.0/2255.0.24.1 to 55.0.27.25455.0.27.2551,022
855.0.28.0/2255.0.28.1 to 55.0.31.25455.0.31.2551,022
955.0.32.0/2255.0.32.1 to 55.0.35.25455.0.35.2551,022
1055.0.36.0/2255.0.36.1 to 55.0.39.25455.0.39.2551,022
1155.0.40.0/2255.0.40.1 to 55.0.43.25455.0.43.2551,022
1255.0.44.0/2255.0.44.1 to 55.0.47.25455.0.47.2551,022
1355.0.48.0/2255.0.48.1 to 55.0.51.25455.0.51.2551,022
1455.0.52.0/2255.0.52.1 to 55.0.55.25455.0.55.2551,022
1555.0.56.0/2255.0.56.1 to 55.0.59.25455.0.59.2551,022
1655.0.60.0/2255.0.60.1 to 55.0.63.25455.0.63.2551,022
1755.0.64.0/2255.0.64.1 to 55.0.67.25455.0.67.2551,022
1855.0.68.0/2255.0.68.1 to 55.0.71.25455.0.71.2551,022
1955.0.72.0/2255.0.72.1 to 55.0.75.25455.0.75.2551,022
2055.0.76.0/2255.0.76.1 to 55.0.79.25455.0.79.2551,022
2155.0.80.0/2255.0.80.1 to 55.0.83.25455.0.83.2551,022
2255.0.84.0/2255.0.84.1 to 55.0.87.25455.0.87.2551,022
2355.0.88.0/2255.0.88.1 to 55.0.91.25455.0.91.2551,022
2455.0.92.0/2255.0.92.1 to 55.0.95.25455.0.95.2551,022
2555.0.96.0/2255.0.96.1 to 55.0.99.25455.0.99.2551,022
2655.0.100.0/2255.0.100.1 to 55.0.103.25455.0.103.2551,022
2755.0.104.0/2255.0.104.1 to 55.0.107.25455.0.107.2551,022
2855.0.108.0/2255.0.108.1 to 55.0.111.25455.0.111.2551,022
2955.0.112.0/2255.0.112.1 to 55.0.115.25455.0.115.2551,022
3055.0.116.0/2255.0.116.1 to 55.0.119.25455.0.119.2551,022
3155.0.120.0/2255.0.120.1 to 55.0.123.25455.0.123.2551,022
3255.0.124.0/2255.0.124.1 to 55.0.127.25455.0.127.2551,022
3355.0.128.0/2255.0.128.1 to 55.0.131.25455.0.131.2551,022
3455.0.132.0/2255.0.132.1 to 55.0.135.25455.0.135.2551,022
3555.0.136.0/2255.0.136.1 to 55.0.139.25455.0.139.2551,022
3655.0.140.0/2255.0.140.1 to 55.0.143.25455.0.143.2551,022
3755.0.144.0/2255.0.144.1 to 55.0.147.25455.0.147.2551,022
3855.0.148.0/2255.0.148.1 to 55.0.151.25455.0.151.2551,022
3955.0.152.0/2255.0.152.1 to 55.0.155.25455.0.155.2551,022
4055.0.156.0/2255.0.156.1 to 55.0.159.25455.0.159.2551,022
4155.0.160.0/2255.0.160.1 to 55.0.163.25455.0.163.2551,022
4255.0.164.0/2255.0.164.1 to 55.0.167.25455.0.167.2551,022
4355.0.168.0/2255.0.168.1 to 55.0.171.25455.0.171.2551,022
4455.0.172.0/2255.0.172.1 to 55.0.175.25455.0.175.2551,022
4555.0.176.0/2255.0.176.1 to 55.0.179.25455.0.179.2551,022
4655.0.180.0/2255.0.180.1 to 55.0.183.25455.0.183.2551,022
4755.0.184.0/2255.0.184.1 to 55.0.187.25455.0.187.2551,022
4855.0.188.0/2255.0.188.1 to 55.0.191.25455.0.191.2551,022
4955.0.192.0/2255.0.192.1 to 55.0.195.25455.0.195.2551,022
5055.0.196.0/2255.0.196.1 to 55.0.199.25455.0.199.2551,022
5155.0.200.0/2255.0.200.1 to 55.0.203.25455.0.203.2551,022
5255.0.204.0/2255.0.204.1 to 55.0.207.25455.0.207.2551,022
5355.0.208.0/2255.0.208.1 to 55.0.211.25455.0.211.2551,022
5455.0.212.0/2255.0.212.1 to 55.0.215.25455.0.215.2551,022
5555.0.216.0/2255.0.216.1 to 55.0.219.25455.0.219.2551,022
5655.0.220.0/2255.0.220.1 to 55.0.223.25455.0.223.2551,022
5755.0.224.0/2255.0.224.1 to 55.0.227.25455.0.227.2551,022
5855.0.228.0/2255.0.228.1 to 55.0.231.25455.0.231.2551,022
5955.0.232.0/2255.0.232.1 to 55.0.235.25455.0.235.2551,022
6055.0.236.0/2255.0.236.1 to 55.0.239.25455.0.239.2551,022
6155.0.240.0/2255.0.240.1 to 55.0.243.25455.0.243.2551,022
6255.0.244.0/2255.0.244.1 to 55.0.247.25455.0.247.2551,022
6355.0.248.0/2255.0.248.1 to 55.0.251.25455.0.251.2551,022
6455.0.252.0/2255.0.252.1 to 55.0.255.25455.0.255.2551,022
6555.1.0.0/2255.1.0.1 to 55.1.3.25455.1.3.2551,022
6655.1.4.0/2255.1.4.1 to 55.1.7.25455.1.7.2551,022
6755.1.8.0/2255.1.8.1 to 55.1.11.25455.1.11.2551,022
6855.1.12.0/2255.1.12.1 to 55.1.15.25455.1.15.2551,022
6955.1.16.0/2255.1.16.1 to 55.1.19.25455.1.19.2551,022
7055.1.20.0/2255.1.20.1 to 55.1.23.25455.1.23.2551,022
7155.1.24.0/2255.1.24.1 to 55.1.27.25455.1.27.2551,022
7255.1.28.0/2255.1.28.1 to 55.1.31.25455.1.31.2551,022
7355.1.32.0/2255.1.32.1 to 55.1.35.25455.1.35.2551,022
7455.1.36.0/2255.1.36.1 to 55.1.39.25455.1.39.2551,022
7555.1.40.0/2255.1.40.1 to 55.1.43.25455.1.43.2551,022
7655.1.44.0/2255.1.44.1 to 55.1.47.25455.1.47.2551,022
7755.1.48.0/2255.1.48.1 to 55.1.51.25455.1.51.2551,022
7855.1.52.0/2255.1.52.1 to 55.1.55.25455.1.55.2551,022
7955.1.56.0/2255.1.56.1 to 55.1.59.25455.1.59.2551,022
8055.1.60.0/2255.1.60.1 to 55.1.63.25455.1.63.2551,022
8155.1.64.0/2255.1.64.1 to 55.1.67.25455.1.67.2551,022
8255.1.68.0/2255.1.68.1 to 55.1.71.25455.1.71.2551,022
8355.1.72.0/2255.1.72.1 to 55.1.75.25455.1.75.2551,022
8455.1.76.0/2255.1.76.1 to 55.1.79.25455.1.79.2551,022
8555.1.80.0/2255.1.80.1 to 55.1.83.25455.1.83.2551,022
8655.1.84.0/2255.1.84.1 to 55.1.87.25455.1.87.2551,022
8755.1.88.0/2255.1.88.1 to 55.1.91.25455.1.91.2551,022
8855.1.92.0/2255.1.92.1 to 55.1.95.25455.1.95.2551,022
8955.1.96.0/2255.1.96.1 to 55.1.99.25455.1.99.2551,022
9055.1.100.0/2255.1.100.1 to 55.1.103.25455.1.103.2551,022
9155.1.104.0/2255.1.104.1 to 55.1.107.25455.1.107.2551,022
9255.1.108.0/2255.1.108.1 to 55.1.111.25455.1.111.2551,022
9355.1.112.0/2255.1.112.1 to 55.1.115.25455.1.115.2551,022
9455.1.116.0/2255.1.116.1 to 55.1.119.25455.1.119.2551,022
9555.1.120.0/2255.1.120.1 to 55.1.123.25455.1.123.2551,022
9655.1.124.0/2255.1.124.1 to 55.1.127.25455.1.127.2551,022
9755.1.128.0/2255.1.128.1 to 55.1.131.25455.1.131.2551,022
9855.1.132.0/2255.1.132.1 to 55.1.135.25455.1.135.2551,022
9955.1.136.0/2255.1.136.1 to 55.1.139.25455.1.139.2551,022
10055.1.140.0/2255.1.140.1 to 55.1.143.25455.1.143.2551,022
10155.1.144.0/2255.1.144.1 to 55.1.147.25455.1.147.2551,022
10255.1.148.0/2255.1.148.1 to 55.1.151.25455.1.151.2551,022
10355.1.152.0/2255.1.152.1 to 55.1.155.25455.1.155.2551,022
10455.1.156.0/2255.1.156.1 to 55.1.159.25455.1.159.2551,022
10555.1.160.0/2255.1.160.1 to 55.1.163.25455.1.163.2551,022
10655.1.164.0/2255.1.164.1 to 55.1.167.25455.1.167.2551,022
10755.1.168.0/2255.1.168.1 to 55.1.171.25455.1.171.2551,022
10855.1.172.0/2255.1.172.1 to 55.1.175.25455.1.175.2551,022
10955.1.176.0/2255.1.176.1 to 55.1.179.25455.1.179.2551,022
11055.1.180.0/2255.1.180.1 to 55.1.183.25455.1.183.2551,022
11155.1.184.0/2255.1.184.1 to 55.1.187.25455.1.187.2551,022
11255.1.188.0/2255.1.188.1 to 55.1.191.25455.1.191.2551,022
11355.1.192.0/2255.1.192.1 to 55.1.195.25455.1.195.2551,022
11455.1.196.0/2255.1.196.1 to 55.1.199.25455.1.199.2551,022
11555.1.200.0/2255.1.200.1 to 55.1.203.25455.1.203.2551,022
11655.1.204.0/2255.1.204.1 to 55.1.207.25455.1.207.2551,022
11755.1.208.0/2255.1.208.1 to 55.1.211.25455.1.211.2551,022
11855.1.212.0/2255.1.212.1 to 55.1.215.25455.1.215.2551,022
11955.1.216.0/2255.1.216.1 to 55.1.219.25455.1.219.2551,022
12055.1.220.0/2255.1.220.1 to 55.1.223.25455.1.223.2551,022
12155.1.224.0/2255.1.224.1 to 55.1.227.25455.1.227.2551,022
12255.1.228.0/2255.1.228.1 to 55.1.231.25455.1.231.2551,022
12355.1.232.0/2255.1.232.1 to 55.1.235.25455.1.235.2551,022
12455.1.236.0/2255.1.236.1 to 55.1.239.25455.1.239.2551,022
12555.1.240.0/2255.1.240.1 to 55.1.243.25455.1.243.2551,022
12655.1.244.0/2255.1.244.1 to 55.1.247.25455.1.247.2551,022
12755.1.248.0/2255.1.248.1 to 55.1.251.25455.1.251.2551,022
12855.1.252.0/2255.1.252.1 to 55.1.255.25455.1.255.2551,022
12955.2.0.0/2255.2.0.1 to 55.2.3.25455.2.3.2551,022
13055.2.4.0/2255.2.4.1 to 55.2.7.25455.2.7.2551,022
13155.2.8.0/2255.2.8.1 to 55.2.11.25455.2.11.2551,022
13255.2.12.0/2255.2.12.1 to 55.2.15.25455.2.15.2551,022
13355.2.16.0/2255.2.16.1 to 55.2.19.25455.2.19.2551,022
13455.2.20.0/2255.2.20.1 to 55.2.23.25455.2.23.2551,022
13555.2.24.0/2255.2.24.1 to 55.2.27.25455.2.27.2551,022
13655.2.28.0/2255.2.28.1 to 55.2.31.25455.2.31.2551,022
13755.2.32.0/2255.2.32.1 to 55.2.35.25455.2.35.2551,022
13855.2.36.0/2255.2.36.1 to 55.2.39.25455.2.39.2551,022
13955.2.40.0/2255.2.40.1 to 55.2.43.25455.2.43.2551,022
14055.2.44.0/2255.2.44.1 to 55.2.47.25455.2.47.2551,022
14155.2.48.0/2255.2.48.1 to 55.2.51.25455.2.51.2551,022
14255.2.52.0/2255.2.52.1 to 55.2.55.25455.2.55.2551,022
14355.2.56.0/2255.2.56.1 to 55.2.59.25455.2.59.2551,022
14455.2.60.0/2255.2.60.1 to 55.2.63.25455.2.63.2551,022
14555.2.64.0/2255.2.64.1 to 55.2.67.25455.2.67.2551,022
14655.2.68.0/2255.2.68.1 to 55.2.71.25455.2.71.2551,022
14755.2.72.0/2255.2.72.1 to 55.2.75.25455.2.75.2551,022
14855.2.76.0/2255.2.76.1 to 55.2.79.25455.2.79.2551,022
14955.2.80.0/2255.2.80.1 to 55.2.83.25455.2.83.2551,022
15055.2.84.0/2255.2.84.1 to 55.2.87.25455.2.87.2551,022
15155.2.88.0/2255.2.88.1 to 55.2.91.25455.2.91.2551,022
15255.2.92.0/2255.2.92.1 to 55.2.95.25455.2.95.2551,022
15355.2.96.0/2255.2.96.1 to 55.2.99.25455.2.99.2551,022
15455.2.100.0/2255.2.100.1 to 55.2.103.25455.2.103.2551,022
15555.2.104.0/2255.2.104.1 to 55.2.107.25455.2.107.2551,022
15655.2.108.0/2255.2.108.1 to 55.2.111.25455.2.111.2551,022
15755.2.112.0/2255.2.112.1 to 55.2.115.25455.2.115.2551,022
15855.2.116.0/2255.2.116.1 to 55.2.119.25455.2.119.2551,022
15955.2.120.0/2255.2.120.1 to 55.2.123.25455.2.123.2551,022
16055.2.124.0/2255.2.124.1 to 55.2.127.25455.2.127.2551,022
16155.2.128.0/2255.2.128.1 to 55.2.131.25455.2.131.2551,022
16255.2.132.0/2255.2.132.1 to 55.2.135.25455.2.135.2551,022
16355.2.136.0/2255.2.136.1 to 55.2.139.25455.2.139.2551,022
16455.2.140.0/2255.2.140.1 to 55.2.143.25455.2.143.2551,022
16555.2.144.0/2255.2.144.1 to 55.2.147.25455.2.147.2551,022
16655.2.148.0/2255.2.148.1 to 55.2.151.25455.2.151.2551,022
16755.2.152.0/2255.2.152.1 to 55.2.155.25455.2.155.2551,022
16855.2.156.0/2255.2.156.1 to 55.2.159.25455.2.159.2551,022
16955.2.160.0/2255.2.160.1 to 55.2.163.25455.2.163.2551,022
17055.2.164.0/2255.2.164.1 to 55.2.167.25455.2.167.2551,022
17155.2.168.0/2255.2.168.1 to 55.2.171.25455.2.171.2551,022
17255.2.172.0/2255.2.172.1 to 55.2.175.25455.2.175.2551,022
17355.2.176.0/2255.2.176.1 to 55.2.179.25455.2.179.2551,022
17455.2.180.0/2255.2.180.1 to 55.2.183.25455.2.183.2551,022
17555.2.184.0/2255.2.184.1 to 55.2.187.25455.2.187.2551,022
17655.2.188.0/2255.2.188.1 to 55.2.191.25455.2.191.2551,022
17755.2.192.0/2255.2.192.1 to 55.2.195.25455.2.195.2551,022
17855.2.196.0/2255.2.196.1 to 55.2.199.25455.2.199.2551,022
17955.2.200.0/2255.2.200.1 to 55.2.203.25455.2.203.2551,022
18055.2.204.0/2255.2.204.1 to 55.2.207.25455.2.207.2551,022
18155.2.208.0/2255.2.208.1 to 55.2.211.25455.2.211.2551,022
18255.2.212.0/2255.2.212.1 to 55.2.215.25455.2.215.2551,022
18355.2.216.0/2255.2.216.1 to 55.2.219.25455.2.219.2551,022
18455.2.220.0/2255.2.220.1 to 55.2.223.25455.2.223.2551,022
18555.2.224.0/2255.2.224.1 to 55.2.227.25455.2.227.2551,022
18655.2.228.0/2255.2.228.1 to 55.2.231.25455.2.231.2551,022
18755.2.232.0/2255.2.232.1 to 55.2.235.25455.2.235.2551,022
18855.2.236.0/2255.2.236.1 to 55.2.239.25455.2.239.2551,022
18955.2.240.0/2255.2.240.1 to 55.2.243.25455.2.243.2551,022
19055.2.244.0/2255.2.244.1 to 55.2.247.25455.2.247.2551,022
19155.2.248.0/2255.2.248.1 to 55.2.251.25455.2.251.2551,022
19255.2.252.0/2255.2.252.1 to 55.2.255.25455.2.255.2551,022
19355.3.0.0/2255.3.0.1 to 55.3.3.25455.3.3.2551,022
19455.3.4.0/2255.3.4.1 to 55.3.7.25455.3.7.2551,022
19555.3.8.0/2255.3.8.1 to 55.3.11.25455.3.11.2551,022
19655.3.12.0/2255.3.12.1 to 55.3.15.25455.3.15.2551,022
19755.3.16.0/2255.3.16.1 to 55.3.19.25455.3.19.2551,022
19855.3.20.0/2255.3.20.1 to 55.3.23.25455.3.23.2551,022
19955.3.24.0/2255.3.24.1 to 55.3.27.25455.3.27.2551,022
20055.3.28.0/2255.3.28.1 to 55.3.31.25455.3.31.2551,022
20155.3.32.0/2255.3.32.1 to 55.3.35.25455.3.35.2551,022
20255.3.36.0/2255.3.36.1 to 55.3.39.25455.3.39.2551,022
20355.3.40.0/2255.3.40.1 to 55.3.43.25455.3.43.2551,022
20455.3.44.0/2255.3.44.1 to 55.3.47.25455.3.47.2551,022
20555.3.48.0/2255.3.48.1 to 55.3.51.25455.3.51.2551,022
20655.3.52.0/2255.3.52.1 to 55.3.55.25455.3.55.2551,022
20755.3.56.0/2255.3.56.1 to 55.3.59.25455.3.59.2551,022
20855.3.60.0/2255.3.60.1 to 55.3.63.25455.3.63.2551,022
20955.3.64.0/2255.3.64.1 to 55.3.67.25455.3.67.2551,022
21055.3.68.0/2255.3.68.1 to 55.3.71.25455.3.71.2551,022
21155.3.72.0/2255.3.72.1 to 55.3.75.25455.3.75.2551,022
21255.3.76.0/2255.3.76.1 to 55.3.79.25455.3.79.2551,022
21355.3.80.0/2255.3.80.1 to 55.3.83.25455.3.83.2551,022
21455.3.84.0/2255.3.84.1 to 55.3.87.25455.3.87.2551,022
21555.3.88.0/2255.3.88.1 to 55.3.91.25455.3.91.2551,022
21655.3.92.0/2255.3.92.1 to 55.3.95.25455.3.95.2551,022
21755.3.96.0/2255.3.96.1 to 55.3.99.25455.3.99.2551,022
21855.3.100.0/2255.3.100.1 to 55.3.103.25455.3.103.2551,022
21955.3.104.0/2255.3.104.1 to 55.3.107.25455.3.107.2551,022
22055.3.108.0/2255.3.108.1 to 55.3.111.25455.3.111.2551,022
22155.3.112.0/2255.3.112.1 to 55.3.115.25455.3.115.2551,022
22255.3.116.0/2255.3.116.1 to 55.3.119.25455.3.119.2551,022
22355.3.120.0/2255.3.120.1 to 55.3.123.25455.3.123.2551,022
22455.3.124.0/2255.3.124.1 to 55.3.127.25455.3.127.2551,022
22555.3.128.0/2255.3.128.1 to 55.3.131.25455.3.131.2551,022
22655.3.132.0/2255.3.132.1 to 55.3.135.25455.3.135.2551,022
22755.3.136.0/2255.3.136.1 to 55.3.139.25455.3.139.2551,022
22855.3.140.0/2255.3.140.1 to 55.3.143.25455.3.143.2551,022
22955.3.144.0/2255.3.144.1 to 55.3.147.25455.3.147.2551,022
23055.3.148.0/2255.3.148.1 to 55.3.151.25455.3.151.2551,022
23155.3.152.0/2255.3.152.1 to 55.3.155.25455.3.155.2551,022
23255.3.156.0/2255.3.156.1 to 55.3.159.25455.3.159.2551,022
23355.3.160.0/2255.3.160.1 to 55.3.163.25455.3.163.2551,022
23455.3.164.0/2255.3.164.1 to 55.3.167.25455.3.167.2551,022
23555.3.168.0/2255.3.168.1 to 55.3.171.25455.3.171.2551,022
23655.3.172.0/2255.3.172.1 to 55.3.175.25455.3.175.2551,022
23755.3.176.0/2255.3.176.1 to 55.3.179.25455.3.179.2551,022
23855.3.180.0/2255.3.180.1 to 55.3.183.25455.3.183.2551,022
23955.3.184.0/2255.3.184.1 to 55.3.187.25455.3.187.2551,022
24055.3.188.0/2255.3.188.1 to 55.3.191.25455.3.191.2551,022
24155.3.192.0/2255.3.192.1 to 55.3.195.25455.3.195.2551,022
24255.3.196.0/2255.3.196.1 to 55.3.199.25455.3.199.2551,022
24355.3.200.0/2255.3.200.1 to 55.3.203.25455.3.203.2551,022
24455.3.204.0/2255.3.204.1 to 55.3.207.25455.3.207.2551,022
24555.3.208.0/2255.3.208.1 to 55.3.211.25455.3.211.2551,022
24655.3.212.0/2255.3.212.1 to 55.3.215.25455.3.215.2551,022
24755.3.216.0/2255.3.216.1 to 55.3.219.25455.3.219.2551,022
24855.3.220.0/2255.3.220.1 to 55.3.223.25455.3.223.2551,022
24955.3.224.0/2255.3.224.1 to 55.3.227.25455.3.227.2551,022
25055.3.228.0/2255.3.228.1 to 55.3.231.25455.3.231.2551,022
25155.3.232.0/2255.3.232.1 to 55.3.235.25455.3.235.2551,022
25255.3.236.0/2255.3.236.1 to 55.3.239.25455.3.239.2551,022
25355.3.240.0/2255.3.240.1 to 55.3.243.25455.3.243.2551,022
25455.3.244.0/2255.3.244.1 to 55.3.247.25455.3.247.2551,022
25555.3.248.0/2255.3.248.1 to 55.3.251.25455.3.251.2551,022
25655.3.252.0/2255.3.252.1 to 55.3.255.25455.3.255.2551,022

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.