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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.

Network17.89.0.0/17
Usable hosts32,766
Subnet mask255.255.128.0
Addresses32,768
Network address
17.89.0.0
Broadcast address
17.89.127.255
First usable
17.89.0.1
Last usable
17.89.127.254
Usable hosts
32,766 (32,768 less the network and broadcast addresses)
Subnet mask
255.255.128.0
Wildcard mask
0.0.127.255 (Cisco ACLs, OSPF)
Prefix length
/17
Type
Public public
Old class
A (default /8)
As numbers
Hex 11590000 · Integer 291045376 to 291078143
Reverse DNS zones
0.89.17.in-addr.arpa
1.89.17.in-addr.arpa
2.89.17.in-addr.arpa
3.89.17.in-addr.arpa
4.89.17.in-addr.arpa
5.89.17.in-addr.arpa
6.89.17.in-addr.arpa
7.89.17.in-addr.arpa
8.89.17.in-addr.arpa
9.89.17.in-addr.arpa
10.89.17.in-addr.arpa
11.89.17.in-addr.arpa
12.89.17.in-addr.arpa
13.89.17.in-addr.arpa
14.89.17.in-addr.arpa
15.89.17.in-addr.arpa
and 112 more
/17 is not on a 8-bit boundary, so it takes 128 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00010001.01011001.00000000.0000000017.89.0.0
Subnet mask11111111.11111111.10000000.00000000255.255.128.0
Network00010001.01011001.00000000.0000000017.89.0.0
Broadcast00010001.01011001.01111111.1111111117.89.127.255
Split into smaller subnets/29
/18 (2)/19 (4)/20 (8)/21 (16)/22 (32)/23 (64)/24 (128)/25 (256)/26 (512)/27 (1,024)/28 (2,048)/29 (4,096)

17.89.0.0/17 makes 4,096 subnets of /29; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
117.89.0.0/2917.89.0.1 to 17.89.0.617.89.0.76
217.89.0.8/2917.89.0.9 to 17.89.0.1417.89.0.156
317.89.0.16/2917.89.0.17 to 17.89.0.2217.89.0.236
417.89.0.24/2917.89.0.25 to 17.89.0.3017.89.0.316
517.89.0.32/2917.89.0.33 to 17.89.0.3817.89.0.396
617.89.0.40/2917.89.0.41 to 17.89.0.4617.89.0.476
717.89.0.48/2917.89.0.49 to 17.89.0.5417.89.0.556
817.89.0.56/2917.89.0.57 to 17.89.0.6217.89.0.636
917.89.0.64/2917.89.0.65 to 17.89.0.7017.89.0.716
1017.89.0.72/2917.89.0.73 to 17.89.0.7817.89.0.796
1117.89.0.80/2917.89.0.81 to 17.89.0.8617.89.0.876
1217.89.0.88/2917.89.0.89 to 17.89.0.9417.89.0.956
1317.89.0.96/2917.89.0.97 to 17.89.0.10217.89.0.1036
1417.89.0.104/2917.89.0.105 to 17.89.0.11017.89.0.1116
1517.89.0.112/2917.89.0.113 to 17.89.0.11817.89.0.1196
1617.89.0.120/2917.89.0.121 to 17.89.0.12617.89.0.1276
1717.89.0.128/2917.89.0.129 to 17.89.0.13417.89.0.1356
1817.89.0.136/2917.89.0.137 to 17.89.0.14217.89.0.1436
1917.89.0.144/2917.89.0.145 to 17.89.0.15017.89.0.1516
2017.89.0.152/2917.89.0.153 to 17.89.0.15817.89.0.1596
2117.89.0.160/2917.89.0.161 to 17.89.0.16617.89.0.1676
2217.89.0.168/2917.89.0.169 to 17.89.0.17417.89.0.1756
2317.89.0.176/2917.89.0.177 to 17.89.0.18217.89.0.1836
2417.89.0.184/2917.89.0.185 to 17.89.0.19017.89.0.1916
2517.89.0.192/2917.89.0.193 to 17.89.0.19817.89.0.1996
2617.89.0.200/2917.89.0.201 to 17.89.0.20617.89.0.2076
2717.89.0.208/2917.89.0.209 to 17.89.0.21417.89.0.2156
2817.89.0.216/2917.89.0.217 to 17.89.0.22217.89.0.2236
2917.89.0.224/2917.89.0.225 to 17.89.0.23017.89.0.2316
3017.89.0.232/2917.89.0.233 to 17.89.0.23817.89.0.2396
3117.89.0.240/2917.89.0.241 to 17.89.0.24617.89.0.2476
3217.89.0.248/2917.89.0.249 to 17.89.0.25417.89.0.2556
3317.89.1.0/2917.89.1.1 to 17.89.1.617.89.1.76
3417.89.1.8/2917.89.1.9 to 17.89.1.1417.89.1.156
3517.89.1.16/2917.89.1.17 to 17.89.1.2217.89.1.236
3617.89.1.24/2917.89.1.25 to 17.89.1.3017.89.1.316
3717.89.1.32/2917.89.1.33 to 17.89.1.3817.89.1.396
3817.89.1.40/2917.89.1.41 to 17.89.1.4617.89.1.476
3917.89.1.48/2917.89.1.49 to 17.89.1.5417.89.1.556
4017.89.1.56/2917.89.1.57 to 17.89.1.6217.89.1.636
4117.89.1.64/2917.89.1.65 to 17.89.1.7017.89.1.716
4217.89.1.72/2917.89.1.73 to 17.89.1.7817.89.1.796
4317.89.1.80/2917.89.1.81 to 17.89.1.8617.89.1.876
4417.89.1.88/2917.89.1.89 to 17.89.1.9417.89.1.956
4517.89.1.96/2917.89.1.97 to 17.89.1.10217.89.1.1036
4617.89.1.104/2917.89.1.105 to 17.89.1.11017.89.1.1116
4717.89.1.112/2917.89.1.113 to 17.89.1.11817.89.1.1196
4817.89.1.120/2917.89.1.121 to 17.89.1.12617.89.1.1276
4917.89.1.128/2917.89.1.129 to 17.89.1.13417.89.1.1356
5017.89.1.136/2917.89.1.137 to 17.89.1.14217.89.1.1436
5117.89.1.144/2917.89.1.145 to 17.89.1.15017.89.1.1516
5217.89.1.152/2917.89.1.153 to 17.89.1.15817.89.1.1596
5317.89.1.160/2917.89.1.161 to 17.89.1.16617.89.1.1676
5417.89.1.168/2917.89.1.169 to 17.89.1.17417.89.1.1756
5517.89.1.176/2917.89.1.177 to 17.89.1.18217.89.1.1836
5617.89.1.184/2917.89.1.185 to 17.89.1.19017.89.1.1916
5717.89.1.192/2917.89.1.193 to 17.89.1.19817.89.1.1996
5817.89.1.200/2917.89.1.201 to 17.89.1.20617.89.1.2076
5917.89.1.208/2917.89.1.209 to 17.89.1.21417.89.1.2156
6017.89.1.216/2917.89.1.217 to 17.89.1.22217.89.1.2236
6117.89.1.224/2917.89.1.225 to 17.89.1.23017.89.1.2316
6217.89.1.232/2917.89.1.233 to 17.89.1.23817.89.1.2396
6317.89.1.240/2917.89.1.241 to 17.89.1.24617.89.1.2476
6417.89.1.248/2917.89.1.249 to 17.89.1.25417.89.1.2556
6517.89.2.0/2917.89.2.1 to 17.89.2.617.89.2.76
6617.89.2.8/2917.89.2.9 to 17.89.2.1417.89.2.156
6717.89.2.16/2917.89.2.17 to 17.89.2.2217.89.2.236
6817.89.2.24/2917.89.2.25 to 17.89.2.3017.89.2.316
6917.89.2.32/2917.89.2.33 to 17.89.2.3817.89.2.396
7017.89.2.40/2917.89.2.41 to 17.89.2.4617.89.2.476
7117.89.2.48/2917.89.2.49 to 17.89.2.5417.89.2.556
7217.89.2.56/2917.89.2.57 to 17.89.2.6217.89.2.636
7317.89.2.64/2917.89.2.65 to 17.89.2.7017.89.2.716
7417.89.2.72/2917.89.2.73 to 17.89.2.7817.89.2.796
7517.89.2.80/2917.89.2.81 to 17.89.2.8617.89.2.876
7617.89.2.88/2917.89.2.89 to 17.89.2.9417.89.2.956
7717.89.2.96/2917.89.2.97 to 17.89.2.10217.89.2.1036
7817.89.2.104/2917.89.2.105 to 17.89.2.11017.89.2.1116
7917.89.2.112/2917.89.2.113 to 17.89.2.11817.89.2.1196
8017.89.2.120/2917.89.2.121 to 17.89.2.12617.89.2.1276
8117.89.2.128/2917.89.2.129 to 17.89.2.13417.89.2.1356
8217.89.2.136/2917.89.2.137 to 17.89.2.14217.89.2.1436
8317.89.2.144/2917.89.2.145 to 17.89.2.15017.89.2.1516
8417.89.2.152/2917.89.2.153 to 17.89.2.15817.89.2.1596
8517.89.2.160/2917.89.2.161 to 17.89.2.16617.89.2.1676
8617.89.2.168/2917.89.2.169 to 17.89.2.17417.89.2.1756
8717.89.2.176/2917.89.2.177 to 17.89.2.18217.89.2.1836
8817.89.2.184/2917.89.2.185 to 17.89.2.19017.89.2.1916
8917.89.2.192/2917.89.2.193 to 17.89.2.19817.89.2.1996
9017.89.2.200/2917.89.2.201 to 17.89.2.20617.89.2.2076
9117.89.2.208/2917.89.2.209 to 17.89.2.21417.89.2.2156
9217.89.2.216/2917.89.2.217 to 17.89.2.22217.89.2.2236
9317.89.2.224/2917.89.2.225 to 17.89.2.23017.89.2.2316
9417.89.2.232/2917.89.2.233 to 17.89.2.23817.89.2.2396
9517.89.2.240/2917.89.2.241 to 17.89.2.24617.89.2.2476
9617.89.2.248/2917.89.2.249 to 17.89.2.25417.89.2.2556
9717.89.3.0/2917.89.3.1 to 17.89.3.617.89.3.76
9817.89.3.8/2917.89.3.9 to 17.89.3.1417.89.3.156
9917.89.3.16/2917.89.3.17 to 17.89.3.2217.89.3.236
10017.89.3.24/2917.89.3.25 to 17.89.3.3017.89.3.316
10117.89.3.32/2917.89.3.33 to 17.89.3.3817.89.3.396
10217.89.3.40/2917.89.3.41 to 17.89.3.4617.89.3.476
10317.89.3.48/2917.89.3.49 to 17.89.3.5417.89.3.556
10417.89.3.56/2917.89.3.57 to 17.89.3.6217.89.3.636
10517.89.3.64/2917.89.3.65 to 17.89.3.7017.89.3.716
10617.89.3.72/2917.89.3.73 to 17.89.3.7817.89.3.796
10717.89.3.80/2917.89.3.81 to 17.89.3.8617.89.3.876
10817.89.3.88/2917.89.3.89 to 17.89.3.9417.89.3.956
10917.89.3.96/2917.89.3.97 to 17.89.3.10217.89.3.1036
11017.89.3.104/2917.89.3.105 to 17.89.3.11017.89.3.1116
11117.89.3.112/2917.89.3.113 to 17.89.3.11817.89.3.1196
11217.89.3.120/2917.89.3.121 to 17.89.3.12617.89.3.1276
11317.89.3.128/2917.89.3.129 to 17.89.3.13417.89.3.1356
11417.89.3.136/2917.89.3.137 to 17.89.3.14217.89.3.1436
11517.89.3.144/2917.89.3.145 to 17.89.3.15017.89.3.1516
11617.89.3.152/2917.89.3.153 to 17.89.3.15817.89.3.1596
11717.89.3.160/2917.89.3.161 to 17.89.3.16617.89.3.1676
11817.89.3.168/2917.89.3.169 to 17.89.3.17417.89.3.1756
11917.89.3.176/2917.89.3.177 to 17.89.3.18217.89.3.1836
12017.89.3.184/2917.89.3.185 to 17.89.3.19017.89.3.1916
12117.89.3.192/2917.89.3.193 to 17.89.3.19817.89.3.1996
12217.89.3.200/2917.89.3.201 to 17.89.3.20617.89.3.2076
12317.89.3.208/2917.89.3.209 to 17.89.3.21417.89.3.2156
12417.89.3.216/2917.89.3.217 to 17.89.3.22217.89.3.2236
12517.89.3.224/2917.89.3.225 to 17.89.3.23017.89.3.2316
12617.89.3.232/2917.89.3.233 to 17.89.3.23817.89.3.2396
12717.89.3.240/2917.89.3.241 to 17.89.3.24617.89.3.2476
12817.89.3.248/2917.89.3.249 to 17.89.3.25417.89.3.2556
12917.89.4.0/2917.89.4.1 to 17.89.4.617.89.4.76
13017.89.4.8/2917.89.4.9 to 17.89.4.1417.89.4.156
13117.89.4.16/2917.89.4.17 to 17.89.4.2217.89.4.236
13217.89.4.24/2917.89.4.25 to 17.89.4.3017.89.4.316
13317.89.4.32/2917.89.4.33 to 17.89.4.3817.89.4.396
13417.89.4.40/2917.89.4.41 to 17.89.4.4617.89.4.476
13517.89.4.48/2917.89.4.49 to 17.89.4.5417.89.4.556
13617.89.4.56/2917.89.4.57 to 17.89.4.6217.89.4.636
13717.89.4.64/2917.89.4.65 to 17.89.4.7017.89.4.716
13817.89.4.72/2917.89.4.73 to 17.89.4.7817.89.4.796
13917.89.4.80/2917.89.4.81 to 17.89.4.8617.89.4.876
14017.89.4.88/2917.89.4.89 to 17.89.4.9417.89.4.956
14117.89.4.96/2917.89.4.97 to 17.89.4.10217.89.4.1036
14217.89.4.104/2917.89.4.105 to 17.89.4.11017.89.4.1116
14317.89.4.112/2917.89.4.113 to 17.89.4.11817.89.4.1196
14417.89.4.120/2917.89.4.121 to 17.89.4.12617.89.4.1276
14517.89.4.128/2917.89.4.129 to 17.89.4.13417.89.4.1356
14617.89.4.136/2917.89.4.137 to 17.89.4.14217.89.4.1436
14717.89.4.144/2917.89.4.145 to 17.89.4.15017.89.4.1516
14817.89.4.152/2917.89.4.153 to 17.89.4.15817.89.4.1596
14917.89.4.160/2917.89.4.161 to 17.89.4.16617.89.4.1676
15017.89.4.168/2917.89.4.169 to 17.89.4.17417.89.4.1756
15117.89.4.176/2917.89.4.177 to 17.89.4.18217.89.4.1836
15217.89.4.184/2917.89.4.185 to 17.89.4.19017.89.4.1916
15317.89.4.192/2917.89.4.193 to 17.89.4.19817.89.4.1996
15417.89.4.200/2917.89.4.201 to 17.89.4.20617.89.4.2076
15517.89.4.208/2917.89.4.209 to 17.89.4.21417.89.4.2156
15617.89.4.216/2917.89.4.217 to 17.89.4.22217.89.4.2236
15717.89.4.224/2917.89.4.225 to 17.89.4.23017.89.4.2316
15817.89.4.232/2917.89.4.233 to 17.89.4.23817.89.4.2396
15917.89.4.240/2917.89.4.241 to 17.89.4.24617.89.4.2476
16017.89.4.248/2917.89.4.249 to 17.89.4.25417.89.4.2556
16117.89.5.0/2917.89.5.1 to 17.89.5.617.89.5.76
16217.89.5.8/2917.89.5.9 to 17.89.5.1417.89.5.156
16317.89.5.16/2917.89.5.17 to 17.89.5.2217.89.5.236
16417.89.5.24/2917.89.5.25 to 17.89.5.3017.89.5.316
16517.89.5.32/2917.89.5.33 to 17.89.5.3817.89.5.396
16617.89.5.40/2917.89.5.41 to 17.89.5.4617.89.5.476
16717.89.5.48/2917.89.5.49 to 17.89.5.5417.89.5.556
16817.89.5.56/2917.89.5.57 to 17.89.5.6217.89.5.636
16917.89.5.64/2917.89.5.65 to 17.89.5.7017.89.5.716
17017.89.5.72/2917.89.5.73 to 17.89.5.7817.89.5.796
17117.89.5.80/2917.89.5.81 to 17.89.5.8617.89.5.876
17217.89.5.88/2917.89.5.89 to 17.89.5.9417.89.5.956
17317.89.5.96/2917.89.5.97 to 17.89.5.10217.89.5.1036
17417.89.5.104/2917.89.5.105 to 17.89.5.11017.89.5.1116
17517.89.5.112/2917.89.5.113 to 17.89.5.11817.89.5.1196
17617.89.5.120/2917.89.5.121 to 17.89.5.12617.89.5.1276
17717.89.5.128/2917.89.5.129 to 17.89.5.13417.89.5.1356
17817.89.5.136/2917.89.5.137 to 17.89.5.14217.89.5.1436
17917.89.5.144/2917.89.5.145 to 17.89.5.15017.89.5.1516
18017.89.5.152/2917.89.5.153 to 17.89.5.15817.89.5.1596
18117.89.5.160/2917.89.5.161 to 17.89.5.16617.89.5.1676
18217.89.5.168/2917.89.5.169 to 17.89.5.17417.89.5.1756
18317.89.5.176/2917.89.5.177 to 17.89.5.18217.89.5.1836
18417.89.5.184/2917.89.5.185 to 17.89.5.19017.89.5.1916
18517.89.5.192/2917.89.5.193 to 17.89.5.19817.89.5.1996
18617.89.5.200/2917.89.5.201 to 17.89.5.20617.89.5.2076
18717.89.5.208/2917.89.5.209 to 17.89.5.21417.89.5.2156
18817.89.5.216/2917.89.5.217 to 17.89.5.22217.89.5.2236
18917.89.5.224/2917.89.5.225 to 17.89.5.23017.89.5.2316
19017.89.5.232/2917.89.5.233 to 17.89.5.23817.89.5.2396
19117.89.5.240/2917.89.5.241 to 17.89.5.24617.89.5.2476
19217.89.5.248/2917.89.5.249 to 17.89.5.25417.89.5.2556
19317.89.6.0/2917.89.6.1 to 17.89.6.617.89.6.76
19417.89.6.8/2917.89.6.9 to 17.89.6.1417.89.6.156
19517.89.6.16/2917.89.6.17 to 17.89.6.2217.89.6.236
19617.89.6.24/2917.89.6.25 to 17.89.6.3017.89.6.316
19717.89.6.32/2917.89.6.33 to 17.89.6.3817.89.6.396
19817.89.6.40/2917.89.6.41 to 17.89.6.4617.89.6.476
19917.89.6.48/2917.89.6.49 to 17.89.6.5417.89.6.556
20017.89.6.56/2917.89.6.57 to 17.89.6.6217.89.6.636
20117.89.6.64/2917.89.6.65 to 17.89.6.7017.89.6.716
20217.89.6.72/2917.89.6.73 to 17.89.6.7817.89.6.796
20317.89.6.80/2917.89.6.81 to 17.89.6.8617.89.6.876
20417.89.6.88/2917.89.6.89 to 17.89.6.9417.89.6.956
20517.89.6.96/2917.89.6.97 to 17.89.6.10217.89.6.1036
20617.89.6.104/2917.89.6.105 to 17.89.6.11017.89.6.1116
20717.89.6.112/2917.89.6.113 to 17.89.6.11817.89.6.1196
20817.89.6.120/2917.89.6.121 to 17.89.6.12617.89.6.1276
20917.89.6.128/2917.89.6.129 to 17.89.6.13417.89.6.1356
21017.89.6.136/2917.89.6.137 to 17.89.6.14217.89.6.1436
21117.89.6.144/2917.89.6.145 to 17.89.6.15017.89.6.1516
21217.89.6.152/2917.89.6.153 to 17.89.6.15817.89.6.1596
21317.89.6.160/2917.89.6.161 to 17.89.6.16617.89.6.1676
21417.89.6.168/2917.89.6.169 to 17.89.6.17417.89.6.1756
21517.89.6.176/2917.89.6.177 to 17.89.6.18217.89.6.1836
21617.89.6.184/2917.89.6.185 to 17.89.6.19017.89.6.1916
21717.89.6.192/2917.89.6.193 to 17.89.6.19817.89.6.1996
21817.89.6.200/2917.89.6.201 to 17.89.6.20617.89.6.2076
21917.89.6.208/2917.89.6.209 to 17.89.6.21417.89.6.2156
22017.89.6.216/2917.89.6.217 to 17.89.6.22217.89.6.2236
22117.89.6.224/2917.89.6.225 to 17.89.6.23017.89.6.2316
22217.89.6.232/2917.89.6.233 to 17.89.6.23817.89.6.2396
22317.89.6.240/2917.89.6.241 to 17.89.6.24617.89.6.2476
22417.89.6.248/2917.89.6.249 to 17.89.6.25417.89.6.2556
22517.89.7.0/2917.89.7.1 to 17.89.7.617.89.7.76
22617.89.7.8/2917.89.7.9 to 17.89.7.1417.89.7.156
22717.89.7.16/2917.89.7.17 to 17.89.7.2217.89.7.236
22817.89.7.24/2917.89.7.25 to 17.89.7.3017.89.7.316
22917.89.7.32/2917.89.7.33 to 17.89.7.3817.89.7.396
23017.89.7.40/2917.89.7.41 to 17.89.7.4617.89.7.476
23117.89.7.48/2917.89.7.49 to 17.89.7.5417.89.7.556
23217.89.7.56/2917.89.7.57 to 17.89.7.6217.89.7.636
23317.89.7.64/2917.89.7.65 to 17.89.7.7017.89.7.716
23417.89.7.72/2917.89.7.73 to 17.89.7.7817.89.7.796
23517.89.7.80/2917.89.7.81 to 17.89.7.8617.89.7.876
23617.89.7.88/2917.89.7.89 to 17.89.7.9417.89.7.956
23717.89.7.96/2917.89.7.97 to 17.89.7.10217.89.7.1036
23817.89.7.104/2917.89.7.105 to 17.89.7.11017.89.7.1116
23917.89.7.112/2917.89.7.113 to 17.89.7.11817.89.7.1196
24017.89.7.120/2917.89.7.121 to 17.89.7.12617.89.7.1276
24117.89.7.128/2917.89.7.129 to 17.89.7.13417.89.7.1356
24217.89.7.136/2917.89.7.137 to 17.89.7.14217.89.7.1436
24317.89.7.144/2917.89.7.145 to 17.89.7.15017.89.7.1516
24417.89.7.152/2917.89.7.153 to 17.89.7.15817.89.7.1596
24517.89.7.160/2917.89.7.161 to 17.89.7.16617.89.7.1676
24617.89.7.168/2917.89.7.169 to 17.89.7.17417.89.7.1756
24717.89.7.176/2917.89.7.177 to 17.89.7.18217.89.7.1836
24817.89.7.184/2917.89.7.185 to 17.89.7.19017.89.7.1916
24917.89.7.192/2917.89.7.193 to 17.89.7.19817.89.7.1996
25017.89.7.200/2917.89.7.201 to 17.89.7.20617.89.7.2076
25117.89.7.208/2917.89.7.209 to 17.89.7.21417.89.7.2156
25217.89.7.216/2917.89.7.217 to 17.89.7.22217.89.7.2236
25317.89.7.224/2917.89.7.225 to 17.89.7.23017.89.7.2316
25417.89.7.232/2917.89.7.233 to 17.89.7.23817.89.7.2396
25517.89.7.240/2917.89.7.241 to 17.89.7.24617.89.7.2476
25617.89.7.248/2917.89.7.249 to 17.89.7.25417.89.7.2556

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.