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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.

Network87.7.112.0/20
Usable hosts4,094
Subnet mask255.255.240.0
Addresses4,096
Network address
87.7.112.0
Broadcast address
87.7.127.255
First usable
87.7.112.1
Last usable
87.7.127.254
Usable hosts
4,094 (4,096 less the network and broadcast addresses)
Subnet mask
255.255.240.0
Wildcard mask
0.0.15.255 (Cisco ACLs, OSPF)
Prefix length
/20
Type
Public public
Old class
A (default /8)
As numbers
Hex 57077000 · Integer 1460105216 to 1460109311
Reverse DNS zones
112.7.87.in-addr.arpa
113.7.87.in-addr.arpa
114.7.87.in-addr.arpa
115.7.87.in-addr.arpa
116.7.87.in-addr.arpa
117.7.87.in-addr.arpa
118.7.87.in-addr.arpa
119.7.87.in-addr.arpa
120.7.87.in-addr.arpa
121.7.87.in-addr.arpa
122.7.87.in-addr.arpa
123.7.87.in-addr.arpa
124.7.87.in-addr.arpa
125.7.87.in-addr.arpa
126.7.87.in-addr.arpa
127.7.87.in-addr.arpa
/20 is not on a 8-bit boundary, so it takes 16 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01010111.00000111.01110000.0000000087.7.112.0
Subnet mask11111111.11111111.11110000.00000000255.255.240.0
Network01010111.00000111.01110000.0000000087.7.112.0
Broadcast01010111.00000111.01111111.1111111187.7.127.255
Split into smaller subnets/28
/21 (2)/22 (4)/23 (8)/24 (16)/25 (32)/26 (64)/27 (128)/28 (256)/29 (512)/30 (1,024)/31 (2,048)/32 (4,096)

87.7.112.0/20 makes 256 subnets of /28.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
187.7.112.0/2887.7.112.1 to 87.7.112.1487.7.112.1514
287.7.112.16/2887.7.112.17 to 87.7.112.3087.7.112.3114
387.7.112.32/2887.7.112.33 to 87.7.112.4687.7.112.4714
487.7.112.48/2887.7.112.49 to 87.7.112.6287.7.112.6314
587.7.112.64/2887.7.112.65 to 87.7.112.7887.7.112.7914
687.7.112.80/2887.7.112.81 to 87.7.112.9487.7.112.9514
787.7.112.96/2887.7.112.97 to 87.7.112.11087.7.112.11114
887.7.112.112/2887.7.112.113 to 87.7.112.12687.7.112.12714
987.7.112.128/2887.7.112.129 to 87.7.112.14287.7.112.14314
1087.7.112.144/2887.7.112.145 to 87.7.112.15887.7.112.15914
1187.7.112.160/2887.7.112.161 to 87.7.112.17487.7.112.17514
1287.7.112.176/2887.7.112.177 to 87.7.112.19087.7.112.19114
1387.7.112.192/2887.7.112.193 to 87.7.112.20687.7.112.20714
1487.7.112.208/2887.7.112.209 to 87.7.112.22287.7.112.22314
1587.7.112.224/2887.7.112.225 to 87.7.112.23887.7.112.23914
1687.7.112.240/2887.7.112.241 to 87.7.112.25487.7.112.25514
1787.7.113.0/2887.7.113.1 to 87.7.113.1487.7.113.1514
1887.7.113.16/2887.7.113.17 to 87.7.113.3087.7.113.3114
1987.7.113.32/2887.7.113.33 to 87.7.113.4687.7.113.4714
2087.7.113.48/2887.7.113.49 to 87.7.113.6287.7.113.6314
2187.7.113.64/2887.7.113.65 to 87.7.113.7887.7.113.7914
2287.7.113.80/2887.7.113.81 to 87.7.113.9487.7.113.9514
2387.7.113.96/2887.7.113.97 to 87.7.113.11087.7.113.11114
2487.7.113.112/2887.7.113.113 to 87.7.113.12687.7.113.12714
2587.7.113.128/2887.7.113.129 to 87.7.113.14287.7.113.14314
2687.7.113.144/2887.7.113.145 to 87.7.113.15887.7.113.15914
2787.7.113.160/2887.7.113.161 to 87.7.113.17487.7.113.17514
2887.7.113.176/2887.7.113.177 to 87.7.113.19087.7.113.19114
2987.7.113.192/2887.7.113.193 to 87.7.113.20687.7.113.20714
3087.7.113.208/2887.7.113.209 to 87.7.113.22287.7.113.22314
3187.7.113.224/2887.7.113.225 to 87.7.113.23887.7.113.23914
3287.7.113.240/2887.7.113.241 to 87.7.113.25487.7.113.25514
3387.7.114.0/2887.7.114.1 to 87.7.114.1487.7.114.1514
3487.7.114.16/2887.7.114.17 to 87.7.114.3087.7.114.3114
3587.7.114.32/2887.7.114.33 to 87.7.114.4687.7.114.4714
3687.7.114.48/2887.7.114.49 to 87.7.114.6287.7.114.6314
3787.7.114.64/2887.7.114.65 to 87.7.114.7887.7.114.7914
3887.7.114.80/2887.7.114.81 to 87.7.114.9487.7.114.9514
3987.7.114.96/2887.7.114.97 to 87.7.114.11087.7.114.11114
4087.7.114.112/2887.7.114.113 to 87.7.114.12687.7.114.12714
4187.7.114.128/2887.7.114.129 to 87.7.114.14287.7.114.14314
4287.7.114.144/2887.7.114.145 to 87.7.114.15887.7.114.15914
4387.7.114.160/2887.7.114.161 to 87.7.114.17487.7.114.17514
4487.7.114.176/2887.7.114.177 to 87.7.114.19087.7.114.19114
4587.7.114.192/2887.7.114.193 to 87.7.114.20687.7.114.20714
4687.7.114.208/2887.7.114.209 to 87.7.114.22287.7.114.22314
4787.7.114.224/2887.7.114.225 to 87.7.114.23887.7.114.23914
4887.7.114.240/2887.7.114.241 to 87.7.114.25487.7.114.25514
4987.7.115.0/2887.7.115.1 to 87.7.115.1487.7.115.1514
5087.7.115.16/2887.7.115.17 to 87.7.115.3087.7.115.3114
5187.7.115.32/2887.7.115.33 to 87.7.115.4687.7.115.4714
5287.7.115.48/2887.7.115.49 to 87.7.115.6287.7.115.6314
5387.7.115.64/2887.7.115.65 to 87.7.115.7887.7.115.7914
5487.7.115.80/2887.7.115.81 to 87.7.115.9487.7.115.9514
5587.7.115.96/2887.7.115.97 to 87.7.115.11087.7.115.11114
5687.7.115.112/2887.7.115.113 to 87.7.115.12687.7.115.12714
5787.7.115.128/2887.7.115.129 to 87.7.115.14287.7.115.14314
5887.7.115.144/2887.7.115.145 to 87.7.115.15887.7.115.15914
5987.7.115.160/2887.7.115.161 to 87.7.115.17487.7.115.17514
6087.7.115.176/2887.7.115.177 to 87.7.115.19087.7.115.19114
6187.7.115.192/2887.7.115.193 to 87.7.115.20687.7.115.20714
6287.7.115.208/2887.7.115.209 to 87.7.115.22287.7.115.22314
6387.7.115.224/2887.7.115.225 to 87.7.115.23887.7.115.23914
6487.7.115.240/2887.7.115.241 to 87.7.115.25487.7.115.25514
6587.7.116.0/2887.7.116.1 to 87.7.116.1487.7.116.1514
6687.7.116.16/2887.7.116.17 to 87.7.116.3087.7.116.3114
6787.7.116.32/2887.7.116.33 to 87.7.116.4687.7.116.4714
6887.7.116.48/2887.7.116.49 to 87.7.116.6287.7.116.6314
6987.7.116.64/2887.7.116.65 to 87.7.116.7887.7.116.7914
7087.7.116.80/2887.7.116.81 to 87.7.116.9487.7.116.9514
7187.7.116.96/2887.7.116.97 to 87.7.116.11087.7.116.11114
7287.7.116.112/2887.7.116.113 to 87.7.116.12687.7.116.12714
7387.7.116.128/2887.7.116.129 to 87.7.116.14287.7.116.14314
7487.7.116.144/2887.7.116.145 to 87.7.116.15887.7.116.15914
7587.7.116.160/2887.7.116.161 to 87.7.116.17487.7.116.17514
7687.7.116.176/2887.7.116.177 to 87.7.116.19087.7.116.19114
7787.7.116.192/2887.7.116.193 to 87.7.116.20687.7.116.20714
7887.7.116.208/2887.7.116.209 to 87.7.116.22287.7.116.22314
7987.7.116.224/2887.7.116.225 to 87.7.116.23887.7.116.23914
8087.7.116.240/2887.7.116.241 to 87.7.116.25487.7.116.25514
8187.7.117.0/2887.7.117.1 to 87.7.117.1487.7.117.1514
8287.7.117.16/2887.7.117.17 to 87.7.117.3087.7.117.3114
8387.7.117.32/2887.7.117.33 to 87.7.117.4687.7.117.4714
8487.7.117.48/2887.7.117.49 to 87.7.117.6287.7.117.6314
8587.7.117.64/2887.7.117.65 to 87.7.117.7887.7.117.7914
8687.7.117.80/2887.7.117.81 to 87.7.117.9487.7.117.9514
8787.7.117.96/2887.7.117.97 to 87.7.117.11087.7.117.11114
8887.7.117.112/2887.7.117.113 to 87.7.117.12687.7.117.12714
8987.7.117.128/2887.7.117.129 to 87.7.117.14287.7.117.14314
9087.7.117.144/2887.7.117.145 to 87.7.117.15887.7.117.15914
9187.7.117.160/2887.7.117.161 to 87.7.117.17487.7.117.17514
9287.7.117.176/2887.7.117.177 to 87.7.117.19087.7.117.19114
9387.7.117.192/2887.7.117.193 to 87.7.117.20687.7.117.20714
9487.7.117.208/2887.7.117.209 to 87.7.117.22287.7.117.22314
9587.7.117.224/2887.7.117.225 to 87.7.117.23887.7.117.23914
9687.7.117.240/2887.7.117.241 to 87.7.117.25487.7.117.25514
9787.7.118.0/2887.7.118.1 to 87.7.118.1487.7.118.1514
9887.7.118.16/2887.7.118.17 to 87.7.118.3087.7.118.3114
9987.7.118.32/2887.7.118.33 to 87.7.118.4687.7.118.4714
10087.7.118.48/2887.7.118.49 to 87.7.118.6287.7.118.6314
10187.7.118.64/2887.7.118.65 to 87.7.118.7887.7.118.7914
10287.7.118.80/2887.7.118.81 to 87.7.118.9487.7.118.9514
10387.7.118.96/2887.7.118.97 to 87.7.118.11087.7.118.11114
10487.7.118.112/2887.7.118.113 to 87.7.118.12687.7.118.12714
10587.7.118.128/2887.7.118.129 to 87.7.118.14287.7.118.14314
10687.7.118.144/2887.7.118.145 to 87.7.118.15887.7.118.15914
10787.7.118.160/2887.7.118.161 to 87.7.118.17487.7.118.17514
10887.7.118.176/2887.7.118.177 to 87.7.118.19087.7.118.19114
10987.7.118.192/2887.7.118.193 to 87.7.118.20687.7.118.20714
11087.7.118.208/2887.7.118.209 to 87.7.118.22287.7.118.22314
11187.7.118.224/2887.7.118.225 to 87.7.118.23887.7.118.23914
11287.7.118.240/2887.7.118.241 to 87.7.118.25487.7.118.25514
11387.7.119.0/2887.7.119.1 to 87.7.119.1487.7.119.1514
11487.7.119.16/2887.7.119.17 to 87.7.119.3087.7.119.3114
11587.7.119.32/2887.7.119.33 to 87.7.119.4687.7.119.4714
11687.7.119.48/2887.7.119.49 to 87.7.119.6287.7.119.6314
11787.7.119.64/2887.7.119.65 to 87.7.119.7887.7.119.7914
11887.7.119.80/2887.7.119.81 to 87.7.119.9487.7.119.9514
11987.7.119.96/2887.7.119.97 to 87.7.119.11087.7.119.11114
12087.7.119.112/2887.7.119.113 to 87.7.119.12687.7.119.12714
12187.7.119.128/2887.7.119.129 to 87.7.119.14287.7.119.14314
12287.7.119.144/2887.7.119.145 to 87.7.119.15887.7.119.15914
12387.7.119.160/2887.7.119.161 to 87.7.119.17487.7.119.17514
12487.7.119.176/2887.7.119.177 to 87.7.119.19087.7.119.19114
12587.7.119.192/2887.7.119.193 to 87.7.119.20687.7.119.20714
12687.7.119.208/2887.7.119.209 to 87.7.119.22287.7.119.22314
12787.7.119.224/2887.7.119.225 to 87.7.119.23887.7.119.23914
12887.7.119.240/2887.7.119.241 to 87.7.119.25487.7.119.25514
12987.7.120.0/2887.7.120.1 to 87.7.120.1487.7.120.1514
13087.7.120.16/2887.7.120.17 to 87.7.120.3087.7.120.3114
13187.7.120.32/2887.7.120.33 to 87.7.120.4687.7.120.4714
13287.7.120.48/2887.7.120.49 to 87.7.120.6287.7.120.6314
13387.7.120.64/2887.7.120.65 to 87.7.120.7887.7.120.7914
13487.7.120.80/2887.7.120.81 to 87.7.120.9487.7.120.9514
13587.7.120.96/2887.7.120.97 to 87.7.120.11087.7.120.11114
13687.7.120.112/2887.7.120.113 to 87.7.120.12687.7.120.12714
13787.7.120.128/2887.7.120.129 to 87.7.120.14287.7.120.14314
13887.7.120.144/2887.7.120.145 to 87.7.120.15887.7.120.15914
13987.7.120.160/2887.7.120.161 to 87.7.120.17487.7.120.17514
14087.7.120.176/2887.7.120.177 to 87.7.120.19087.7.120.19114
14187.7.120.192/2887.7.120.193 to 87.7.120.20687.7.120.20714
14287.7.120.208/2887.7.120.209 to 87.7.120.22287.7.120.22314
14387.7.120.224/2887.7.120.225 to 87.7.120.23887.7.120.23914
14487.7.120.240/2887.7.120.241 to 87.7.120.25487.7.120.25514
14587.7.121.0/2887.7.121.1 to 87.7.121.1487.7.121.1514
14687.7.121.16/2887.7.121.17 to 87.7.121.3087.7.121.3114
14787.7.121.32/2887.7.121.33 to 87.7.121.4687.7.121.4714
14887.7.121.48/2887.7.121.49 to 87.7.121.6287.7.121.6314
14987.7.121.64/2887.7.121.65 to 87.7.121.7887.7.121.7914
15087.7.121.80/2887.7.121.81 to 87.7.121.9487.7.121.9514
15187.7.121.96/2887.7.121.97 to 87.7.121.11087.7.121.11114
15287.7.121.112/2887.7.121.113 to 87.7.121.12687.7.121.12714
15387.7.121.128/2887.7.121.129 to 87.7.121.14287.7.121.14314
15487.7.121.144/2887.7.121.145 to 87.7.121.15887.7.121.15914
15587.7.121.160/2887.7.121.161 to 87.7.121.17487.7.121.17514
15687.7.121.176/2887.7.121.177 to 87.7.121.19087.7.121.19114
15787.7.121.192/2887.7.121.193 to 87.7.121.20687.7.121.20714
15887.7.121.208/2887.7.121.209 to 87.7.121.22287.7.121.22314
15987.7.121.224/2887.7.121.225 to 87.7.121.23887.7.121.23914
16087.7.121.240/2887.7.121.241 to 87.7.121.25487.7.121.25514
16187.7.122.0/2887.7.122.1 to 87.7.122.1487.7.122.1514
16287.7.122.16/2887.7.122.17 to 87.7.122.3087.7.122.3114
16387.7.122.32/2887.7.122.33 to 87.7.122.4687.7.122.4714
16487.7.122.48/2887.7.122.49 to 87.7.122.6287.7.122.6314
16587.7.122.64/2887.7.122.65 to 87.7.122.7887.7.122.7914
16687.7.122.80/2887.7.122.81 to 87.7.122.9487.7.122.9514
16787.7.122.96/2887.7.122.97 to 87.7.122.11087.7.122.11114
16887.7.122.112/2887.7.122.113 to 87.7.122.12687.7.122.12714
16987.7.122.128/2887.7.122.129 to 87.7.122.14287.7.122.14314
17087.7.122.144/2887.7.122.145 to 87.7.122.15887.7.122.15914
17187.7.122.160/2887.7.122.161 to 87.7.122.17487.7.122.17514
17287.7.122.176/2887.7.122.177 to 87.7.122.19087.7.122.19114
17387.7.122.192/2887.7.122.193 to 87.7.122.20687.7.122.20714
17487.7.122.208/2887.7.122.209 to 87.7.122.22287.7.122.22314
17587.7.122.224/2887.7.122.225 to 87.7.122.23887.7.122.23914
17687.7.122.240/2887.7.122.241 to 87.7.122.25487.7.122.25514
17787.7.123.0/2887.7.123.1 to 87.7.123.1487.7.123.1514
17887.7.123.16/2887.7.123.17 to 87.7.123.3087.7.123.3114
17987.7.123.32/2887.7.123.33 to 87.7.123.4687.7.123.4714
18087.7.123.48/2887.7.123.49 to 87.7.123.6287.7.123.6314
18187.7.123.64/2887.7.123.65 to 87.7.123.7887.7.123.7914
18287.7.123.80/2887.7.123.81 to 87.7.123.9487.7.123.9514
18387.7.123.96/2887.7.123.97 to 87.7.123.11087.7.123.11114
18487.7.123.112/2887.7.123.113 to 87.7.123.12687.7.123.12714
18587.7.123.128/2887.7.123.129 to 87.7.123.14287.7.123.14314
18687.7.123.144/2887.7.123.145 to 87.7.123.15887.7.123.15914
18787.7.123.160/2887.7.123.161 to 87.7.123.17487.7.123.17514
18887.7.123.176/2887.7.123.177 to 87.7.123.19087.7.123.19114
18987.7.123.192/2887.7.123.193 to 87.7.123.20687.7.123.20714
19087.7.123.208/2887.7.123.209 to 87.7.123.22287.7.123.22314
19187.7.123.224/2887.7.123.225 to 87.7.123.23887.7.123.23914
19287.7.123.240/2887.7.123.241 to 87.7.123.25487.7.123.25514
19387.7.124.0/2887.7.124.1 to 87.7.124.1487.7.124.1514
19487.7.124.16/2887.7.124.17 to 87.7.124.3087.7.124.3114
19587.7.124.32/2887.7.124.33 to 87.7.124.4687.7.124.4714
19687.7.124.48/2887.7.124.49 to 87.7.124.6287.7.124.6314
19787.7.124.64/2887.7.124.65 to 87.7.124.7887.7.124.7914
19887.7.124.80/2887.7.124.81 to 87.7.124.9487.7.124.9514
19987.7.124.96/2887.7.124.97 to 87.7.124.11087.7.124.11114
20087.7.124.112/2887.7.124.113 to 87.7.124.12687.7.124.12714
20187.7.124.128/2887.7.124.129 to 87.7.124.14287.7.124.14314
20287.7.124.144/2887.7.124.145 to 87.7.124.15887.7.124.15914
20387.7.124.160/2887.7.124.161 to 87.7.124.17487.7.124.17514
20487.7.124.176/2887.7.124.177 to 87.7.124.19087.7.124.19114
20587.7.124.192/2887.7.124.193 to 87.7.124.20687.7.124.20714
20687.7.124.208/2887.7.124.209 to 87.7.124.22287.7.124.22314
20787.7.124.224/2887.7.124.225 to 87.7.124.23887.7.124.23914
20887.7.124.240/2887.7.124.241 to 87.7.124.25487.7.124.25514
20987.7.125.0/2887.7.125.1 to 87.7.125.1487.7.125.1514
21087.7.125.16/2887.7.125.17 to 87.7.125.3087.7.125.3114
21187.7.125.32/2887.7.125.33 to 87.7.125.4687.7.125.4714
21287.7.125.48/2887.7.125.49 to 87.7.125.6287.7.125.6314
21387.7.125.64/2887.7.125.65 to 87.7.125.7887.7.125.7914
21487.7.125.80/2887.7.125.81 to 87.7.125.9487.7.125.9514
21587.7.125.96/2887.7.125.97 to 87.7.125.11087.7.125.11114
21687.7.125.112/2887.7.125.113 to 87.7.125.12687.7.125.12714
21787.7.125.128/2887.7.125.129 to 87.7.125.14287.7.125.14314
21887.7.125.144/2887.7.125.145 to 87.7.125.15887.7.125.15914
21987.7.125.160/2887.7.125.161 to 87.7.125.17487.7.125.17514
22087.7.125.176/2887.7.125.177 to 87.7.125.19087.7.125.19114
22187.7.125.192/2887.7.125.193 to 87.7.125.20687.7.125.20714
22287.7.125.208/2887.7.125.209 to 87.7.125.22287.7.125.22314
22387.7.125.224/2887.7.125.225 to 87.7.125.23887.7.125.23914
22487.7.125.240/2887.7.125.241 to 87.7.125.25487.7.125.25514
22587.7.126.0/2887.7.126.1 to 87.7.126.1487.7.126.1514
22687.7.126.16/2887.7.126.17 to 87.7.126.3087.7.126.3114
22787.7.126.32/2887.7.126.33 to 87.7.126.4687.7.126.4714
22887.7.126.48/2887.7.126.49 to 87.7.126.6287.7.126.6314
22987.7.126.64/2887.7.126.65 to 87.7.126.7887.7.126.7914
23087.7.126.80/2887.7.126.81 to 87.7.126.9487.7.126.9514
23187.7.126.96/2887.7.126.97 to 87.7.126.11087.7.126.11114
23287.7.126.112/2887.7.126.113 to 87.7.126.12687.7.126.12714
23387.7.126.128/2887.7.126.129 to 87.7.126.14287.7.126.14314
23487.7.126.144/2887.7.126.145 to 87.7.126.15887.7.126.15914
23587.7.126.160/2887.7.126.161 to 87.7.126.17487.7.126.17514
23687.7.126.176/2887.7.126.177 to 87.7.126.19087.7.126.19114
23787.7.126.192/2887.7.126.193 to 87.7.126.20687.7.126.20714
23887.7.126.208/2887.7.126.209 to 87.7.126.22287.7.126.22314
23987.7.126.224/2887.7.126.225 to 87.7.126.23887.7.126.23914
24087.7.126.240/2887.7.126.241 to 87.7.126.25487.7.126.25514
24187.7.127.0/2887.7.127.1 to 87.7.127.1487.7.127.1514
24287.7.127.16/2887.7.127.17 to 87.7.127.3087.7.127.3114
24387.7.127.32/2887.7.127.33 to 87.7.127.4687.7.127.4714
24487.7.127.48/2887.7.127.49 to 87.7.127.6287.7.127.6314
24587.7.127.64/2887.7.127.65 to 87.7.127.7887.7.127.7914
24687.7.127.80/2887.7.127.81 to 87.7.127.9487.7.127.9514
24787.7.127.96/2887.7.127.97 to 87.7.127.11087.7.127.11114
24887.7.127.112/2887.7.127.113 to 87.7.127.12687.7.127.12714
24987.7.127.128/2887.7.127.129 to 87.7.127.14287.7.127.14314
25087.7.127.144/2887.7.127.145 to 87.7.127.15887.7.127.15914
25187.7.127.160/2887.7.127.161 to 87.7.127.17487.7.127.17514
25287.7.127.176/2887.7.127.177 to 87.7.127.19087.7.127.19114
25387.7.127.192/2887.7.127.193 to 87.7.127.20687.7.127.20714
25487.7.127.208/2887.7.127.209 to 87.7.127.22287.7.127.22314
25587.7.127.224/2887.7.127.225 to 87.7.127.23887.7.127.23914
25687.7.127.240/2887.7.127.241 to 87.7.127.25487.7.127.25514

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.