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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.

Network79.2.64.0/18
Usable hosts16,382
Subnet mask255.255.192.0
Addresses16,384
Network address
79.2.64.0
Broadcast address
79.2.127.255
First usable
79.2.64.1
Last usable
79.2.127.254
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 4F024000 · Integer 1325547520 to 1325563903
Reverse DNS zones
64.2.79.in-addr.arpa
65.2.79.in-addr.arpa
66.2.79.in-addr.arpa
67.2.79.in-addr.arpa
68.2.79.in-addr.arpa
69.2.79.in-addr.arpa
70.2.79.in-addr.arpa
71.2.79.in-addr.arpa
72.2.79.in-addr.arpa
73.2.79.in-addr.arpa
74.2.79.in-addr.arpa
75.2.79.in-addr.arpa
76.2.79.in-addr.arpa
77.2.79.in-addr.arpa
78.2.79.in-addr.arpa
79.2.79.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
Address01001111.00000010.01000000.0000000079.2.64.0
Subnet mask11111111.11111111.11000000.00000000255.255.192.0
Network01001111.00000010.01000000.0000000079.2.64.0
Broadcast01001111.00000010.01111111.1111111179.2.127.255
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)

79.2.64.0/18 makes 2,048 subnets of /29; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
179.2.64.0/2979.2.64.1 to 79.2.64.679.2.64.76
279.2.64.8/2979.2.64.9 to 79.2.64.1479.2.64.156
379.2.64.16/2979.2.64.17 to 79.2.64.2279.2.64.236
479.2.64.24/2979.2.64.25 to 79.2.64.3079.2.64.316
579.2.64.32/2979.2.64.33 to 79.2.64.3879.2.64.396
679.2.64.40/2979.2.64.41 to 79.2.64.4679.2.64.476
779.2.64.48/2979.2.64.49 to 79.2.64.5479.2.64.556
879.2.64.56/2979.2.64.57 to 79.2.64.6279.2.64.636
979.2.64.64/2979.2.64.65 to 79.2.64.7079.2.64.716
1079.2.64.72/2979.2.64.73 to 79.2.64.7879.2.64.796
1179.2.64.80/2979.2.64.81 to 79.2.64.8679.2.64.876
1279.2.64.88/2979.2.64.89 to 79.2.64.9479.2.64.956
1379.2.64.96/2979.2.64.97 to 79.2.64.10279.2.64.1036
1479.2.64.104/2979.2.64.105 to 79.2.64.11079.2.64.1116
1579.2.64.112/2979.2.64.113 to 79.2.64.11879.2.64.1196
1679.2.64.120/2979.2.64.121 to 79.2.64.12679.2.64.1276
1779.2.64.128/2979.2.64.129 to 79.2.64.13479.2.64.1356
1879.2.64.136/2979.2.64.137 to 79.2.64.14279.2.64.1436
1979.2.64.144/2979.2.64.145 to 79.2.64.15079.2.64.1516
2079.2.64.152/2979.2.64.153 to 79.2.64.15879.2.64.1596
2179.2.64.160/2979.2.64.161 to 79.2.64.16679.2.64.1676
2279.2.64.168/2979.2.64.169 to 79.2.64.17479.2.64.1756
2379.2.64.176/2979.2.64.177 to 79.2.64.18279.2.64.1836
2479.2.64.184/2979.2.64.185 to 79.2.64.19079.2.64.1916
2579.2.64.192/2979.2.64.193 to 79.2.64.19879.2.64.1996
2679.2.64.200/2979.2.64.201 to 79.2.64.20679.2.64.2076
2779.2.64.208/2979.2.64.209 to 79.2.64.21479.2.64.2156
2879.2.64.216/2979.2.64.217 to 79.2.64.22279.2.64.2236
2979.2.64.224/2979.2.64.225 to 79.2.64.23079.2.64.2316
3079.2.64.232/2979.2.64.233 to 79.2.64.23879.2.64.2396
3179.2.64.240/2979.2.64.241 to 79.2.64.24679.2.64.2476
3279.2.64.248/2979.2.64.249 to 79.2.64.25479.2.64.2556
3379.2.65.0/2979.2.65.1 to 79.2.65.679.2.65.76
3479.2.65.8/2979.2.65.9 to 79.2.65.1479.2.65.156
3579.2.65.16/2979.2.65.17 to 79.2.65.2279.2.65.236
3679.2.65.24/2979.2.65.25 to 79.2.65.3079.2.65.316
3779.2.65.32/2979.2.65.33 to 79.2.65.3879.2.65.396
3879.2.65.40/2979.2.65.41 to 79.2.65.4679.2.65.476
3979.2.65.48/2979.2.65.49 to 79.2.65.5479.2.65.556
4079.2.65.56/2979.2.65.57 to 79.2.65.6279.2.65.636
4179.2.65.64/2979.2.65.65 to 79.2.65.7079.2.65.716
4279.2.65.72/2979.2.65.73 to 79.2.65.7879.2.65.796
4379.2.65.80/2979.2.65.81 to 79.2.65.8679.2.65.876
4479.2.65.88/2979.2.65.89 to 79.2.65.9479.2.65.956
4579.2.65.96/2979.2.65.97 to 79.2.65.10279.2.65.1036
4679.2.65.104/2979.2.65.105 to 79.2.65.11079.2.65.1116
4779.2.65.112/2979.2.65.113 to 79.2.65.11879.2.65.1196
4879.2.65.120/2979.2.65.121 to 79.2.65.12679.2.65.1276
4979.2.65.128/2979.2.65.129 to 79.2.65.13479.2.65.1356
5079.2.65.136/2979.2.65.137 to 79.2.65.14279.2.65.1436
5179.2.65.144/2979.2.65.145 to 79.2.65.15079.2.65.1516
5279.2.65.152/2979.2.65.153 to 79.2.65.15879.2.65.1596
5379.2.65.160/2979.2.65.161 to 79.2.65.16679.2.65.1676
5479.2.65.168/2979.2.65.169 to 79.2.65.17479.2.65.1756
5579.2.65.176/2979.2.65.177 to 79.2.65.18279.2.65.1836
5679.2.65.184/2979.2.65.185 to 79.2.65.19079.2.65.1916
5779.2.65.192/2979.2.65.193 to 79.2.65.19879.2.65.1996
5879.2.65.200/2979.2.65.201 to 79.2.65.20679.2.65.2076
5979.2.65.208/2979.2.65.209 to 79.2.65.21479.2.65.2156
6079.2.65.216/2979.2.65.217 to 79.2.65.22279.2.65.2236
6179.2.65.224/2979.2.65.225 to 79.2.65.23079.2.65.2316
6279.2.65.232/2979.2.65.233 to 79.2.65.23879.2.65.2396
6379.2.65.240/2979.2.65.241 to 79.2.65.24679.2.65.2476
6479.2.65.248/2979.2.65.249 to 79.2.65.25479.2.65.2556
6579.2.66.0/2979.2.66.1 to 79.2.66.679.2.66.76
6679.2.66.8/2979.2.66.9 to 79.2.66.1479.2.66.156
6779.2.66.16/2979.2.66.17 to 79.2.66.2279.2.66.236
6879.2.66.24/2979.2.66.25 to 79.2.66.3079.2.66.316
6979.2.66.32/2979.2.66.33 to 79.2.66.3879.2.66.396
7079.2.66.40/2979.2.66.41 to 79.2.66.4679.2.66.476
7179.2.66.48/2979.2.66.49 to 79.2.66.5479.2.66.556
7279.2.66.56/2979.2.66.57 to 79.2.66.6279.2.66.636
7379.2.66.64/2979.2.66.65 to 79.2.66.7079.2.66.716
7479.2.66.72/2979.2.66.73 to 79.2.66.7879.2.66.796
7579.2.66.80/2979.2.66.81 to 79.2.66.8679.2.66.876
7679.2.66.88/2979.2.66.89 to 79.2.66.9479.2.66.956
7779.2.66.96/2979.2.66.97 to 79.2.66.10279.2.66.1036
7879.2.66.104/2979.2.66.105 to 79.2.66.11079.2.66.1116
7979.2.66.112/2979.2.66.113 to 79.2.66.11879.2.66.1196
8079.2.66.120/2979.2.66.121 to 79.2.66.12679.2.66.1276
8179.2.66.128/2979.2.66.129 to 79.2.66.13479.2.66.1356
8279.2.66.136/2979.2.66.137 to 79.2.66.14279.2.66.1436
8379.2.66.144/2979.2.66.145 to 79.2.66.15079.2.66.1516
8479.2.66.152/2979.2.66.153 to 79.2.66.15879.2.66.1596
8579.2.66.160/2979.2.66.161 to 79.2.66.16679.2.66.1676
8679.2.66.168/2979.2.66.169 to 79.2.66.17479.2.66.1756
8779.2.66.176/2979.2.66.177 to 79.2.66.18279.2.66.1836
8879.2.66.184/2979.2.66.185 to 79.2.66.19079.2.66.1916
8979.2.66.192/2979.2.66.193 to 79.2.66.19879.2.66.1996
9079.2.66.200/2979.2.66.201 to 79.2.66.20679.2.66.2076
9179.2.66.208/2979.2.66.209 to 79.2.66.21479.2.66.2156
9279.2.66.216/2979.2.66.217 to 79.2.66.22279.2.66.2236
9379.2.66.224/2979.2.66.225 to 79.2.66.23079.2.66.2316
9479.2.66.232/2979.2.66.233 to 79.2.66.23879.2.66.2396
9579.2.66.240/2979.2.66.241 to 79.2.66.24679.2.66.2476
9679.2.66.248/2979.2.66.249 to 79.2.66.25479.2.66.2556
9779.2.67.0/2979.2.67.1 to 79.2.67.679.2.67.76
9879.2.67.8/2979.2.67.9 to 79.2.67.1479.2.67.156
9979.2.67.16/2979.2.67.17 to 79.2.67.2279.2.67.236
10079.2.67.24/2979.2.67.25 to 79.2.67.3079.2.67.316
10179.2.67.32/2979.2.67.33 to 79.2.67.3879.2.67.396
10279.2.67.40/2979.2.67.41 to 79.2.67.4679.2.67.476
10379.2.67.48/2979.2.67.49 to 79.2.67.5479.2.67.556
10479.2.67.56/2979.2.67.57 to 79.2.67.6279.2.67.636
10579.2.67.64/2979.2.67.65 to 79.2.67.7079.2.67.716
10679.2.67.72/2979.2.67.73 to 79.2.67.7879.2.67.796
10779.2.67.80/2979.2.67.81 to 79.2.67.8679.2.67.876
10879.2.67.88/2979.2.67.89 to 79.2.67.9479.2.67.956
10979.2.67.96/2979.2.67.97 to 79.2.67.10279.2.67.1036
11079.2.67.104/2979.2.67.105 to 79.2.67.11079.2.67.1116
11179.2.67.112/2979.2.67.113 to 79.2.67.11879.2.67.1196
11279.2.67.120/2979.2.67.121 to 79.2.67.12679.2.67.1276
11379.2.67.128/2979.2.67.129 to 79.2.67.13479.2.67.1356
11479.2.67.136/2979.2.67.137 to 79.2.67.14279.2.67.1436
11579.2.67.144/2979.2.67.145 to 79.2.67.15079.2.67.1516
11679.2.67.152/2979.2.67.153 to 79.2.67.15879.2.67.1596
11779.2.67.160/2979.2.67.161 to 79.2.67.16679.2.67.1676
11879.2.67.168/2979.2.67.169 to 79.2.67.17479.2.67.1756
11979.2.67.176/2979.2.67.177 to 79.2.67.18279.2.67.1836
12079.2.67.184/2979.2.67.185 to 79.2.67.19079.2.67.1916
12179.2.67.192/2979.2.67.193 to 79.2.67.19879.2.67.1996
12279.2.67.200/2979.2.67.201 to 79.2.67.20679.2.67.2076
12379.2.67.208/2979.2.67.209 to 79.2.67.21479.2.67.2156
12479.2.67.216/2979.2.67.217 to 79.2.67.22279.2.67.2236
12579.2.67.224/2979.2.67.225 to 79.2.67.23079.2.67.2316
12679.2.67.232/2979.2.67.233 to 79.2.67.23879.2.67.2396
12779.2.67.240/2979.2.67.241 to 79.2.67.24679.2.67.2476
12879.2.67.248/2979.2.67.249 to 79.2.67.25479.2.67.2556
12979.2.68.0/2979.2.68.1 to 79.2.68.679.2.68.76
13079.2.68.8/2979.2.68.9 to 79.2.68.1479.2.68.156
13179.2.68.16/2979.2.68.17 to 79.2.68.2279.2.68.236
13279.2.68.24/2979.2.68.25 to 79.2.68.3079.2.68.316
13379.2.68.32/2979.2.68.33 to 79.2.68.3879.2.68.396
13479.2.68.40/2979.2.68.41 to 79.2.68.4679.2.68.476
13579.2.68.48/2979.2.68.49 to 79.2.68.5479.2.68.556
13679.2.68.56/2979.2.68.57 to 79.2.68.6279.2.68.636
13779.2.68.64/2979.2.68.65 to 79.2.68.7079.2.68.716
13879.2.68.72/2979.2.68.73 to 79.2.68.7879.2.68.796
13979.2.68.80/2979.2.68.81 to 79.2.68.8679.2.68.876
14079.2.68.88/2979.2.68.89 to 79.2.68.9479.2.68.956
14179.2.68.96/2979.2.68.97 to 79.2.68.10279.2.68.1036
14279.2.68.104/2979.2.68.105 to 79.2.68.11079.2.68.1116
14379.2.68.112/2979.2.68.113 to 79.2.68.11879.2.68.1196
14479.2.68.120/2979.2.68.121 to 79.2.68.12679.2.68.1276
14579.2.68.128/2979.2.68.129 to 79.2.68.13479.2.68.1356
14679.2.68.136/2979.2.68.137 to 79.2.68.14279.2.68.1436
14779.2.68.144/2979.2.68.145 to 79.2.68.15079.2.68.1516
14879.2.68.152/2979.2.68.153 to 79.2.68.15879.2.68.1596
14979.2.68.160/2979.2.68.161 to 79.2.68.16679.2.68.1676
15079.2.68.168/2979.2.68.169 to 79.2.68.17479.2.68.1756
15179.2.68.176/2979.2.68.177 to 79.2.68.18279.2.68.1836
15279.2.68.184/2979.2.68.185 to 79.2.68.19079.2.68.1916
15379.2.68.192/2979.2.68.193 to 79.2.68.19879.2.68.1996
15479.2.68.200/2979.2.68.201 to 79.2.68.20679.2.68.2076
15579.2.68.208/2979.2.68.209 to 79.2.68.21479.2.68.2156
15679.2.68.216/2979.2.68.217 to 79.2.68.22279.2.68.2236
15779.2.68.224/2979.2.68.225 to 79.2.68.23079.2.68.2316
15879.2.68.232/2979.2.68.233 to 79.2.68.23879.2.68.2396
15979.2.68.240/2979.2.68.241 to 79.2.68.24679.2.68.2476
16079.2.68.248/2979.2.68.249 to 79.2.68.25479.2.68.2556
16179.2.69.0/2979.2.69.1 to 79.2.69.679.2.69.76
16279.2.69.8/2979.2.69.9 to 79.2.69.1479.2.69.156
16379.2.69.16/2979.2.69.17 to 79.2.69.2279.2.69.236
16479.2.69.24/2979.2.69.25 to 79.2.69.3079.2.69.316
16579.2.69.32/2979.2.69.33 to 79.2.69.3879.2.69.396
16679.2.69.40/2979.2.69.41 to 79.2.69.4679.2.69.476
16779.2.69.48/2979.2.69.49 to 79.2.69.5479.2.69.556
16879.2.69.56/2979.2.69.57 to 79.2.69.6279.2.69.636
16979.2.69.64/2979.2.69.65 to 79.2.69.7079.2.69.716
17079.2.69.72/2979.2.69.73 to 79.2.69.7879.2.69.796
17179.2.69.80/2979.2.69.81 to 79.2.69.8679.2.69.876
17279.2.69.88/2979.2.69.89 to 79.2.69.9479.2.69.956
17379.2.69.96/2979.2.69.97 to 79.2.69.10279.2.69.1036
17479.2.69.104/2979.2.69.105 to 79.2.69.11079.2.69.1116
17579.2.69.112/2979.2.69.113 to 79.2.69.11879.2.69.1196
17679.2.69.120/2979.2.69.121 to 79.2.69.12679.2.69.1276
17779.2.69.128/2979.2.69.129 to 79.2.69.13479.2.69.1356
17879.2.69.136/2979.2.69.137 to 79.2.69.14279.2.69.1436
17979.2.69.144/2979.2.69.145 to 79.2.69.15079.2.69.1516
18079.2.69.152/2979.2.69.153 to 79.2.69.15879.2.69.1596
18179.2.69.160/2979.2.69.161 to 79.2.69.16679.2.69.1676
18279.2.69.168/2979.2.69.169 to 79.2.69.17479.2.69.1756
18379.2.69.176/2979.2.69.177 to 79.2.69.18279.2.69.1836
18479.2.69.184/2979.2.69.185 to 79.2.69.19079.2.69.1916
18579.2.69.192/2979.2.69.193 to 79.2.69.19879.2.69.1996
18679.2.69.200/2979.2.69.201 to 79.2.69.20679.2.69.2076
18779.2.69.208/2979.2.69.209 to 79.2.69.21479.2.69.2156
18879.2.69.216/2979.2.69.217 to 79.2.69.22279.2.69.2236
18979.2.69.224/2979.2.69.225 to 79.2.69.23079.2.69.2316
19079.2.69.232/2979.2.69.233 to 79.2.69.23879.2.69.2396
19179.2.69.240/2979.2.69.241 to 79.2.69.24679.2.69.2476
19279.2.69.248/2979.2.69.249 to 79.2.69.25479.2.69.2556
19379.2.70.0/2979.2.70.1 to 79.2.70.679.2.70.76
19479.2.70.8/2979.2.70.9 to 79.2.70.1479.2.70.156
19579.2.70.16/2979.2.70.17 to 79.2.70.2279.2.70.236
19679.2.70.24/2979.2.70.25 to 79.2.70.3079.2.70.316
19779.2.70.32/2979.2.70.33 to 79.2.70.3879.2.70.396
19879.2.70.40/2979.2.70.41 to 79.2.70.4679.2.70.476
19979.2.70.48/2979.2.70.49 to 79.2.70.5479.2.70.556
20079.2.70.56/2979.2.70.57 to 79.2.70.6279.2.70.636
20179.2.70.64/2979.2.70.65 to 79.2.70.7079.2.70.716
20279.2.70.72/2979.2.70.73 to 79.2.70.7879.2.70.796
20379.2.70.80/2979.2.70.81 to 79.2.70.8679.2.70.876
20479.2.70.88/2979.2.70.89 to 79.2.70.9479.2.70.956
20579.2.70.96/2979.2.70.97 to 79.2.70.10279.2.70.1036
20679.2.70.104/2979.2.70.105 to 79.2.70.11079.2.70.1116
20779.2.70.112/2979.2.70.113 to 79.2.70.11879.2.70.1196
20879.2.70.120/2979.2.70.121 to 79.2.70.12679.2.70.1276
20979.2.70.128/2979.2.70.129 to 79.2.70.13479.2.70.1356
21079.2.70.136/2979.2.70.137 to 79.2.70.14279.2.70.1436
21179.2.70.144/2979.2.70.145 to 79.2.70.15079.2.70.1516
21279.2.70.152/2979.2.70.153 to 79.2.70.15879.2.70.1596
21379.2.70.160/2979.2.70.161 to 79.2.70.16679.2.70.1676
21479.2.70.168/2979.2.70.169 to 79.2.70.17479.2.70.1756
21579.2.70.176/2979.2.70.177 to 79.2.70.18279.2.70.1836
21679.2.70.184/2979.2.70.185 to 79.2.70.19079.2.70.1916
21779.2.70.192/2979.2.70.193 to 79.2.70.19879.2.70.1996
21879.2.70.200/2979.2.70.201 to 79.2.70.20679.2.70.2076
21979.2.70.208/2979.2.70.209 to 79.2.70.21479.2.70.2156
22079.2.70.216/2979.2.70.217 to 79.2.70.22279.2.70.2236
22179.2.70.224/2979.2.70.225 to 79.2.70.23079.2.70.2316
22279.2.70.232/2979.2.70.233 to 79.2.70.23879.2.70.2396
22379.2.70.240/2979.2.70.241 to 79.2.70.24679.2.70.2476
22479.2.70.248/2979.2.70.249 to 79.2.70.25479.2.70.2556
22579.2.71.0/2979.2.71.1 to 79.2.71.679.2.71.76
22679.2.71.8/2979.2.71.9 to 79.2.71.1479.2.71.156
22779.2.71.16/2979.2.71.17 to 79.2.71.2279.2.71.236
22879.2.71.24/2979.2.71.25 to 79.2.71.3079.2.71.316
22979.2.71.32/2979.2.71.33 to 79.2.71.3879.2.71.396
23079.2.71.40/2979.2.71.41 to 79.2.71.4679.2.71.476
23179.2.71.48/2979.2.71.49 to 79.2.71.5479.2.71.556
23279.2.71.56/2979.2.71.57 to 79.2.71.6279.2.71.636
23379.2.71.64/2979.2.71.65 to 79.2.71.7079.2.71.716
23479.2.71.72/2979.2.71.73 to 79.2.71.7879.2.71.796
23579.2.71.80/2979.2.71.81 to 79.2.71.8679.2.71.876
23679.2.71.88/2979.2.71.89 to 79.2.71.9479.2.71.956
23779.2.71.96/2979.2.71.97 to 79.2.71.10279.2.71.1036
23879.2.71.104/2979.2.71.105 to 79.2.71.11079.2.71.1116
23979.2.71.112/2979.2.71.113 to 79.2.71.11879.2.71.1196
24079.2.71.120/2979.2.71.121 to 79.2.71.12679.2.71.1276
24179.2.71.128/2979.2.71.129 to 79.2.71.13479.2.71.1356
24279.2.71.136/2979.2.71.137 to 79.2.71.14279.2.71.1436
24379.2.71.144/2979.2.71.145 to 79.2.71.15079.2.71.1516
24479.2.71.152/2979.2.71.153 to 79.2.71.15879.2.71.1596
24579.2.71.160/2979.2.71.161 to 79.2.71.16679.2.71.1676
24679.2.71.168/2979.2.71.169 to 79.2.71.17479.2.71.1756
24779.2.71.176/2979.2.71.177 to 79.2.71.18279.2.71.1836
24879.2.71.184/2979.2.71.185 to 79.2.71.19079.2.71.1916
24979.2.71.192/2979.2.71.193 to 79.2.71.19879.2.71.1996
25079.2.71.200/2979.2.71.201 to 79.2.71.20679.2.71.2076
25179.2.71.208/2979.2.71.209 to 79.2.71.21479.2.71.2156
25279.2.71.216/2979.2.71.217 to 79.2.71.22279.2.71.2236
25379.2.71.224/2979.2.71.225 to 79.2.71.23079.2.71.2316
25479.2.71.232/2979.2.71.233 to 79.2.71.23879.2.71.2396
25579.2.71.240/2979.2.71.241 to 79.2.71.24679.2.71.2476
25679.2.71.248/2979.2.71.249 to 79.2.71.25479.2.71.2556

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.