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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.

Network68.136.128.0/18
Usable hosts16,382
Subnet mask255.255.192.0
Addresses16,384
Network address
68.136.128.0
Broadcast address
68.136.191.255
First usable
68.136.128.1
Last usable
68.136.191.254
Usable hosts
16,382 (16,384 less the network and broadcast addresses)
Subnet mask
255.255.192.0
Wildcard mask
0.0.63.255 (Cisco ACLs, OSPF)
Prefix length
/18
Type
Public public
Old class
A (default /8)
As numbers
Hex 44888000 · Integer 1149796352 to 1149812735
Reverse DNS zones
128.136.68.in-addr.arpa
129.136.68.in-addr.arpa
130.136.68.in-addr.arpa
131.136.68.in-addr.arpa
132.136.68.in-addr.arpa
133.136.68.in-addr.arpa
134.136.68.in-addr.arpa
135.136.68.in-addr.arpa
136.136.68.in-addr.arpa
137.136.68.in-addr.arpa
138.136.68.in-addr.arpa
139.136.68.in-addr.arpa
140.136.68.in-addr.arpa
141.136.68.in-addr.arpa
142.136.68.in-addr.arpa
143.136.68.in-addr.arpa
and 48 more
/18 is not on a 8-bit boundary, so it takes 64 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01000100.10001000.10000000.0000000068.136.128.0
Subnet mask11111111.11111111.11000000.00000000255.255.192.0
Network01000100.10001000.10000000.0000000068.136.128.0
Broadcast01000100.10001000.10111111.1111111168.136.191.255
Split into smaller subnets/29
/19 (2)/20 (4)/21 (8)/22 (16)/23 (32)/24 (64)/25 (128)/26 (256)/27 (512)/28 (1,024)/29 (2,048)/30 (4,096)

68.136.128.0/18 makes 2,048 subnets of /29; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
168.136.128.0/2968.136.128.1 to 68.136.128.668.136.128.76
268.136.128.8/2968.136.128.9 to 68.136.128.1468.136.128.156
368.136.128.16/2968.136.128.17 to 68.136.128.2268.136.128.236
468.136.128.24/2968.136.128.25 to 68.136.128.3068.136.128.316
568.136.128.32/2968.136.128.33 to 68.136.128.3868.136.128.396
668.136.128.40/2968.136.128.41 to 68.136.128.4668.136.128.476
768.136.128.48/2968.136.128.49 to 68.136.128.5468.136.128.556
868.136.128.56/2968.136.128.57 to 68.136.128.6268.136.128.636
968.136.128.64/2968.136.128.65 to 68.136.128.7068.136.128.716
1068.136.128.72/2968.136.128.73 to 68.136.128.7868.136.128.796
1168.136.128.80/2968.136.128.81 to 68.136.128.8668.136.128.876
1268.136.128.88/2968.136.128.89 to 68.136.128.9468.136.128.956
1368.136.128.96/2968.136.128.97 to 68.136.128.10268.136.128.1036
1468.136.128.104/2968.136.128.105 to 68.136.128.11068.136.128.1116
1568.136.128.112/2968.136.128.113 to 68.136.128.11868.136.128.1196
1668.136.128.120/2968.136.128.121 to 68.136.128.12668.136.128.1276
1768.136.128.128/2968.136.128.129 to 68.136.128.13468.136.128.1356
1868.136.128.136/2968.136.128.137 to 68.136.128.14268.136.128.1436
1968.136.128.144/2968.136.128.145 to 68.136.128.15068.136.128.1516
2068.136.128.152/2968.136.128.153 to 68.136.128.15868.136.128.1596
2168.136.128.160/2968.136.128.161 to 68.136.128.16668.136.128.1676
2268.136.128.168/2968.136.128.169 to 68.136.128.17468.136.128.1756
2368.136.128.176/2968.136.128.177 to 68.136.128.18268.136.128.1836
2468.136.128.184/2968.136.128.185 to 68.136.128.19068.136.128.1916
2568.136.128.192/2968.136.128.193 to 68.136.128.19868.136.128.1996
2668.136.128.200/2968.136.128.201 to 68.136.128.20668.136.128.2076
2768.136.128.208/2968.136.128.209 to 68.136.128.21468.136.128.2156
2868.136.128.216/2968.136.128.217 to 68.136.128.22268.136.128.2236
2968.136.128.224/2968.136.128.225 to 68.136.128.23068.136.128.2316
3068.136.128.232/2968.136.128.233 to 68.136.128.23868.136.128.2396
3168.136.128.240/2968.136.128.241 to 68.136.128.24668.136.128.2476
3268.136.128.248/2968.136.128.249 to 68.136.128.25468.136.128.2556
3368.136.129.0/2968.136.129.1 to 68.136.129.668.136.129.76
3468.136.129.8/2968.136.129.9 to 68.136.129.1468.136.129.156
3568.136.129.16/2968.136.129.17 to 68.136.129.2268.136.129.236
3668.136.129.24/2968.136.129.25 to 68.136.129.3068.136.129.316
3768.136.129.32/2968.136.129.33 to 68.136.129.3868.136.129.396
3868.136.129.40/2968.136.129.41 to 68.136.129.4668.136.129.476
3968.136.129.48/2968.136.129.49 to 68.136.129.5468.136.129.556
4068.136.129.56/2968.136.129.57 to 68.136.129.6268.136.129.636
4168.136.129.64/2968.136.129.65 to 68.136.129.7068.136.129.716
4268.136.129.72/2968.136.129.73 to 68.136.129.7868.136.129.796
4368.136.129.80/2968.136.129.81 to 68.136.129.8668.136.129.876
4468.136.129.88/2968.136.129.89 to 68.136.129.9468.136.129.956
4568.136.129.96/2968.136.129.97 to 68.136.129.10268.136.129.1036
4668.136.129.104/2968.136.129.105 to 68.136.129.11068.136.129.1116
4768.136.129.112/2968.136.129.113 to 68.136.129.11868.136.129.1196
4868.136.129.120/2968.136.129.121 to 68.136.129.12668.136.129.1276
4968.136.129.128/2968.136.129.129 to 68.136.129.13468.136.129.1356
5068.136.129.136/2968.136.129.137 to 68.136.129.14268.136.129.1436
5168.136.129.144/2968.136.129.145 to 68.136.129.15068.136.129.1516
5268.136.129.152/2968.136.129.153 to 68.136.129.15868.136.129.1596
5368.136.129.160/2968.136.129.161 to 68.136.129.16668.136.129.1676
5468.136.129.168/2968.136.129.169 to 68.136.129.17468.136.129.1756
5568.136.129.176/2968.136.129.177 to 68.136.129.18268.136.129.1836
5668.136.129.184/2968.136.129.185 to 68.136.129.19068.136.129.1916
5768.136.129.192/2968.136.129.193 to 68.136.129.19868.136.129.1996
5868.136.129.200/2968.136.129.201 to 68.136.129.20668.136.129.2076
5968.136.129.208/2968.136.129.209 to 68.136.129.21468.136.129.2156
6068.136.129.216/2968.136.129.217 to 68.136.129.22268.136.129.2236
6168.136.129.224/2968.136.129.225 to 68.136.129.23068.136.129.2316
6268.136.129.232/2968.136.129.233 to 68.136.129.23868.136.129.2396
6368.136.129.240/2968.136.129.241 to 68.136.129.24668.136.129.2476
6468.136.129.248/2968.136.129.249 to 68.136.129.25468.136.129.2556
6568.136.130.0/2968.136.130.1 to 68.136.130.668.136.130.76
6668.136.130.8/2968.136.130.9 to 68.136.130.1468.136.130.156
6768.136.130.16/2968.136.130.17 to 68.136.130.2268.136.130.236
6868.136.130.24/2968.136.130.25 to 68.136.130.3068.136.130.316
6968.136.130.32/2968.136.130.33 to 68.136.130.3868.136.130.396
7068.136.130.40/2968.136.130.41 to 68.136.130.4668.136.130.476
7168.136.130.48/2968.136.130.49 to 68.136.130.5468.136.130.556
7268.136.130.56/2968.136.130.57 to 68.136.130.6268.136.130.636
7368.136.130.64/2968.136.130.65 to 68.136.130.7068.136.130.716
7468.136.130.72/2968.136.130.73 to 68.136.130.7868.136.130.796
7568.136.130.80/2968.136.130.81 to 68.136.130.8668.136.130.876
7668.136.130.88/2968.136.130.89 to 68.136.130.9468.136.130.956
7768.136.130.96/2968.136.130.97 to 68.136.130.10268.136.130.1036
7868.136.130.104/2968.136.130.105 to 68.136.130.11068.136.130.1116
7968.136.130.112/2968.136.130.113 to 68.136.130.11868.136.130.1196
8068.136.130.120/2968.136.130.121 to 68.136.130.12668.136.130.1276
8168.136.130.128/2968.136.130.129 to 68.136.130.13468.136.130.1356
8268.136.130.136/2968.136.130.137 to 68.136.130.14268.136.130.1436
8368.136.130.144/2968.136.130.145 to 68.136.130.15068.136.130.1516
8468.136.130.152/2968.136.130.153 to 68.136.130.15868.136.130.1596
8568.136.130.160/2968.136.130.161 to 68.136.130.16668.136.130.1676
8668.136.130.168/2968.136.130.169 to 68.136.130.17468.136.130.1756
8768.136.130.176/2968.136.130.177 to 68.136.130.18268.136.130.1836
8868.136.130.184/2968.136.130.185 to 68.136.130.19068.136.130.1916
8968.136.130.192/2968.136.130.193 to 68.136.130.19868.136.130.1996
9068.136.130.200/2968.136.130.201 to 68.136.130.20668.136.130.2076
9168.136.130.208/2968.136.130.209 to 68.136.130.21468.136.130.2156
9268.136.130.216/2968.136.130.217 to 68.136.130.22268.136.130.2236
9368.136.130.224/2968.136.130.225 to 68.136.130.23068.136.130.2316
9468.136.130.232/2968.136.130.233 to 68.136.130.23868.136.130.2396
9568.136.130.240/2968.136.130.241 to 68.136.130.24668.136.130.2476
9668.136.130.248/2968.136.130.249 to 68.136.130.25468.136.130.2556
9768.136.131.0/2968.136.131.1 to 68.136.131.668.136.131.76
9868.136.131.8/2968.136.131.9 to 68.136.131.1468.136.131.156
9968.136.131.16/2968.136.131.17 to 68.136.131.2268.136.131.236
10068.136.131.24/2968.136.131.25 to 68.136.131.3068.136.131.316
10168.136.131.32/2968.136.131.33 to 68.136.131.3868.136.131.396
10268.136.131.40/2968.136.131.41 to 68.136.131.4668.136.131.476
10368.136.131.48/2968.136.131.49 to 68.136.131.5468.136.131.556
10468.136.131.56/2968.136.131.57 to 68.136.131.6268.136.131.636
10568.136.131.64/2968.136.131.65 to 68.136.131.7068.136.131.716
10668.136.131.72/2968.136.131.73 to 68.136.131.7868.136.131.796
10768.136.131.80/2968.136.131.81 to 68.136.131.8668.136.131.876
10868.136.131.88/2968.136.131.89 to 68.136.131.9468.136.131.956
10968.136.131.96/2968.136.131.97 to 68.136.131.10268.136.131.1036
11068.136.131.104/2968.136.131.105 to 68.136.131.11068.136.131.1116
11168.136.131.112/2968.136.131.113 to 68.136.131.11868.136.131.1196
11268.136.131.120/2968.136.131.121 to 68.136.131.12668.136.131.1276
11368.136.131.128/2968.136.131.129 to 68.136.131.13468.136.131.1356
11468.136.131.136/2968.136.131.137 to 68.136.131.14268.136.131.1436
11568.136.131.144/2968.136.131.145 to 68.136.131.15068.136.131.1516
11668.136.131.152/2968.136.131.153 to 68.136.131.15868.136.131.1596
11768.136.131.160/2968.136.131.161 to 68.136.131.16668.136.131.1676
11868.136.131.168/2968.136.131.169 to 68.136.131.17468.136.131.1756
11968.136.131.176/2968.136.131.177 to 68.136.131.18268.136.131.1836
12068.136.131.184/2968.136.131.185 to 68.136.131.19068.136.131.1916
12168.136.131.192/2968.136.131.193 to 68.136.131.19868.136.131.1996
12268.136.131.200/2968.136.131.201 to 68.136.131.20668.136.131.2076
12368.136.131.208/2968.136.131.209 to 68.136.131.21468.136.131.2156
12468.136.131.216/2968.136.131.217 to 68.136.131.22268.136.131.2236
12568.136.131.224/2968.136.131.225 to 68.136.131.23068.136.131.2316
12668.136.131.232/2968.136.131.233 to 68.136.131.23868.136.131.2396
12768.136.131.240/2968.136.131.241 to 68.136.131.24668.136.131.2476
12868.136.131.248/2968.136.131.249 to 68.136.131.25468.136.131.2556
12968.136.132.0/2968.136.132.1 to 68.136.132.668.136.132.76
13068.136.132.8/2968.136.132.9 to 68.136.132.1468.136.132.156
13168.136.132.16/2968.136.132.17 to 68.136.132.2268.136.132.236
13268.136.132.24/2968.136.132.25 to 68.136.132.3068.136.132.316
13368.136.132.32/2968.136.132.33 to 68.136.132.3868.136.132.396
13468.136.132.40/2968.136.132.41 to 68.136.132.4668.136.132.476
13568.136.132.48/2968.136.132.49 to 68.136.132.5468.136.132.556
13668.136.132.56/2968.136.132.57 to 68.136.132.6268.136.132.636
13768.136.132.64/2968.136.132.65 to 68.136.132.7068.136.132.716
13868.136.132.72/2968.136.132.73 to 68.136.132.7868.136.132.796
13968.136.132.80/2968.136.132.81 to 68.136.132.8668.136.132.876
14068.136.132.88/2968.136.132.89 to 68.136.132.9468.136.132.956
14168.136.132.96/2968.136.132.97 to 68.136.132.10268.136.132.1036
14268.136.132.104/2968.136.132.105 to 68.136.132.11068.136.132.1116
14368.136.132.112/2968.136.132.113 to 68.136.132.11868.136.132.1196
14468.136.132.120/2968.136.132.121 to 68.136.132.12668.136.132.1276
14568.136.132.128/2968.136.132.129 to 68.136.132.13468.136.132.1356
14668.136.132.136/2968.136.132.137 to 68.136.132.14268.136.132.1436
14768.136.132.144/2968.136.132.145 to 68.136.132.15068.136.132.1516
14868.136.132.152/2968.136.132.153 to 68.136.132.15868.136.132.1596
14968.136.132.160/2968.136.132.161 to 68.136.132.16668.136.132.1676
15068.136.132.168/2968.136.132.169 to 68.136.132.17468.136.132.1756
15168.136.132.176/2968.136.132.177 to 68.136.132.18268.136.132.1836
15268.136.132.184/2968.136.132.185 to 68.136.132.19068.136.132.1916
15368.136.132.192/2968.136.132.193 to 68.136.132.19868.136.132.1996
15468.136.132.200/2968.136.132.201 to 68.136.132.20668.136.132.2076
15568.136.132.208/2968.136.132.209 to 68.136.132.21468.136.132.2156
15668.136.132.216/2968.136.132.217 to 68.136.132.22268.136.132.2236
15768.136.132.224/2968.136.132.225 to 68.136.132.23068.136.132.2316
15868.136.132.232/2968.136.132.233 to 68.136.132.23868.136.132.2396
15968.136.132.240/2968.136.132.241 to 68.136.132.24668.136.132.2476
16068.136.132.248/2968.136.132.249 to 68.136.132.25468.136.132.2556
16168.136.133.0/2968.136.133.1 to 68.136.133.668.136.133.76
16268.136.133.8/2968.136.133.9 to 68.136.133.1468.136.133.156
16368.136.133.16/2968.136.133.17 to 68.136.133.2268.136.133.236
16468.136.133.24/2968.136.133.25 to 68.136.133.3068.136.133.316
16568.136.133.32/2968.136.133.33 to 68.136.133.3868.136.133.396
16668.136.133.40/2968.136.133.41 to 68.136.133.4668.136.133.476
16768.136.133.48/2968.136.133.49 to 68.136.133.5468.136.133.556
16868.136.133.56/2968.136.133.57 to 68.136.133.6268.136.133.636
16968.136.133.64/2968.136.133.65 to 68.136.133.7068.136.133.716
17068.136.133.72/2968.136.133.73 to 68.136.133.7868.136.133.796
17168.136.133.80/2968.136.133.81 to 68.136.133.8668.136.133.876
17268.136.133.88/2968.136.133.89 to 68.136.133.9468.136.133.956
17368.136.133.96/2968.136.133.97 to 68.136.133.10268.136.133.1036
17468.136.133.104/2968.136.133.105 to 68.136.133.11068.136.133.1116
17568.136.133.112/2968.136.133.113 to 68.136.133.11868.136.133.1196
17668.136.133.120/2968.136.133.121 to 68.136.133.12668.136.133.1276
17768.136.133.128/2968.136.133.129 to 68.136.133.13468.136.133.1356
17868.136.133.136/2968.136.133.137 to 68.136.133.14268.136.133.1436
17968.136.133.144/2968.136.133.145 to 68.136.133.15068.136.133.1516
18068.136.133.152/2968.136.133.153 to 68.136.133.15868.136.133.1596
18168.136.133.160/2968.136.133.161 to 68.136.133.16668.136.133.1676
18268.136.133.168/2968.136.133.169 to 68.136.133.17468.136.133.1756
18368.136.133.176/2968.136.133.177 to 68.136.133.18268.136.133.1836
18468.136.133.184/2968.136.133.185 to 68.136.133.19068.136.133.1916
18568.136.133.192/2968.136.133.193 to 68.136.133.19868.136.133.1996
18668.136.133.200/2968.136.133.201 to 68.136.133.20668.136.133.2076
18768.136.133.208/2968.136.133.209 to 68.136.133.21468.136.133.2156
18868.136.133.216/2968.136.133.217 to 68.136.133.22268.136.133.2236
18968.136.133.224/2968.136.133.225 to 68.136.133.23068.136.133.2316
19068.136.133.232/2968.136.133.233 to 68.136.133.23868.136.133.2396
19168.136.133.240/2968.136.133.241 to 68.136.133.24668.136.133.2476
19268.136.133.248/2968.136.133.249 to 68.136.133.25468.136.133.2556
19368.136.134.0/2968.136.134.1 to 68.136.134.668.136.134.76
19468.136.134.8/2968.136.134.9 to 68.136.134.1468.136.134.156
19568.136.134.16/2968.136.134.17 to 68.136.134.2268.136.134.236
19668.136.134.24/2968.136.134.25 to 68.136.134.3068.136.134.316
19768.136.134.32/2968.136.134.33 to 68.136.134.3868.136.134.396
19868.136.134.40/2968.136.134.41 to 68.136.134.4668.136.134.476
19968.136.134.48/2968.136.134.49 to 68.136.134.5468.136.134.556
20068.136.134.56/2968.136.134.57 to 68.136.134.6268.136.134.636
20168.136.134.64/2968.136.134.65 to 68.136.134.7068.136.134.716
20268.136.134.72/2968.136.134.73 to 68.136.134.7868.136.134.796
20368.136.134.80/2968.136.134.81 to 68.136.134.8668.136.134.876
20468.136.134.88/2968.136.134.89 to 68.136.134.9468.136.134.956
20568.136.134.96/2968.136.134.97 to 68.136.134.10268.136.134.1036
20668.136.134.104/2968.136.134.105 to 68.136.134.11068.136.134.1116
20768.136.134.112/2968.136.134.113 to 68.136.134.11868.136.134.1196
20868.136.134.120/2968.136.134.121 to 68.136.134.12668.136.134.1276
20968.136.134.128/2968.136.134.129 to 68.136.134.13468.136.134.1356
21068.136.134.136/2968.136.134.137 to 68.136.134.14268.136.134.1436
21168.136.134.144/2968.136.134.145 to 68.136.134.15068.136.134.1516
21268.136.134.152/2968.136.134.153 to 68.136.134.15868.136.134.1596
21368.136.134.160/2968.136.134.161 to 68.136.134.16668.136.134.1676
21468.136.134.168/2968.136.134.169 to 68.136.134.17468.136.134.1756
21568.136.134.176/2968.136.134.177 to 68.136.134.18268.136.134.1836
21668.136.134.184/2968.136.134.185 to 68.136.134.19068.136.134.1916
21768.136.134.192/2968.136.134.193 to 68.136.134.19868.136.134.1996
21868.136.134.200/2968.136.134.201 to 68.136.134.20668.136.134.2076
21968.136.134.208/2968.136.134.209 to 68.136.134.21468.136.134.2156
22068.136.134.216/2968.136.134.217 to 68.136.134.22268.136.134.2236
22168.136.134.224/2968.136.134.225 to 68.136.134.23068.136.134.2316
22268.136.134.232/2968.136.134.233 to 68.136.134.23868.136.134.2396
22368.136.134.240/2968.136.134.241 to 68.136.134.24668.136.134.2476
22468.136.134.248/2968.136.134.249 to 68.136.134.25468.136.134.2556
22568.136.135.0/2968.136.135.1 to 68.136.135.668.136.135.76
22668.136.135.8/2968.136.135.9 to 68.136.135.1468.136.135.156
22768.136.135.16/2968.136.135.17 to 68.136.135.2268.136.135.236
22868.136.135.24/2968.136.135.25 to 68.136.135.3068.136.135.316
22968.136.135.32/2968.136.135.33 to 68.136.135.3868.136.135.396
23068.136.135.40/2968.136.135.41 to 68.136.135.4668.136.135.476
23168.136.135.48/2968.136.135.49 to 68.136.135.5468.136.135.556
23268.136.135.56/2968.136.135.57 to 68.136.135.6268.136.135.636
23368.136.135.64/2968.136.135.65 to 68.136.135.7068.136.135.716
23468.136.135.72/2968.136.135.73 to 68.136.135.7868.136.135.796
23568.136.135.80/2968.136.135.81 to 68.136.135.8668.136.135.876
23668.136.135.88/2968.136.135.89 to 68.136.135.9468.136.135.956
23768.136.135.96/2968.136.135.97 to 68.136.135.10268.136.135.1036
23868.136.135.104/2968.136.135.105 to 68.136.135.11068.136.135.1116
23968.136.135.112/2968.136.135.113 to 68.136.135.11868.136.135.1196
24068.136.135.120/2968.136.135.121 to 68.136.135.12668.136.135.1276
24168.136.135.128/2968.136.135.129 to 68.136.135.13468.136.135.1356
24268.136.135.136/2968.136.135.137 to 68.136.135.14268.136.135.1436
24368.136.135.144/2968.136.135.145 to 68.136.135.15068.136.135.1516
24468.136.135.152/2968.136.135.153 to 68.136.135.15868.136.135.1596
24568.136.135.160/2968.136.135.161 to 68.136.135.16668.136.135.1676
24668.136.135.168/2968.136.135.169 to 68.136.135.17468.136.135.1756
24768.136.135.176/2968.136.135.177 to 68.136.135.18268.136.135.1836
24868.136.135.184/2968.136.135.185 to 68.136.135.19068.136.135.1916
24968.136.135.192/2968.136.135.193 to 68.136.135.19868.136.135.1996
25068.136.135.200/2968.136.135.201 to 68.136.135.20668.136.135.2076
25168.136.135.208/2968.136.135.209 to 68.136.135.21468.136.135.2156
25268.136.135.216/2968.136.135.217 to 68.136.135.22268.136.135.2236
25368.136.135.224/2968.136.135.225 to 68.136.135.23068.136.135.2316
25468.136.135.232/2968.136.135.233 to 68.136.135.23868.136.135.2396
25568.136.135.240/2968.136.135.241 to 68.136.135.24668.136.135.2476
25668.136.135.248/2968.136.135.249 to 68.136.135.25468.136.135.2556

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.