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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.

Network70.7.64.0/18
Usable hosts16,382
Subnet mask255.255.192.0
Addresses16,384
Network address
70.7.64.0
Broadcast address
70.7.127.255
First usable
70.7.64.1
Last usable
70.7.127.254
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 46074000 · Integer 1174880256 to 1174896639
Reverse DNS zones
64.7.70.in-addr.arpa
65.7.70.in-addr.arpa
66.7.70.in-addr.arpa
67.7.70.in-addr.arpa
68.7.70.in-addr.arpa
69.7.70.in-addr.arpa
70.7.70.in-addr.arpa
71.7.70.in-addr.arpa
72.7.70.in-addr.arpa
73.7.70.in-addr.arpa
74.7.70.in-addr.arpa
75.7.70.in-addr.arpa
76.7.70.in-addr.arpa
77.7.70.in-addr.arpa
78.7.70.in-addr.arpa
79.7.70.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
Address01000110.00000111.01000000.0000000070.7.64.0
Subnet mask11111111.11111111.11000000.00000000255.255.192.0
Network01000110.00000111.01000000.0000000070.7.64.0
Broadcast01000110.00000111.01111111.1111111170.7.127.255
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)

70.7.64.0/18 makes 2,048 subnets of /29; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
170.7.64.0/2970.7.64.1 to 70.7.64.670.7.64.76
270.7.64.8/2970.7.64.9 to 70.7.64.1470.7.64.156
370.7.64.16/2970.7.64.17 to 70.7.64.2270.7.64.236
470.7.64.24/2970.7.64.25 to 70.7.64.3070.7.64.316
570.7.64.32/2970.7.64.33 to 70.7.64.3870.7.64.396
670.7.64.40/2970.7.64.41 to 70.7.64.4670.7.64.476
770.7.64.48/2970.7.64.49 to 70.7.64.5470.7.64.556
870.7.64.56/2970.7.64.57 to 70.7.64.6270.7.64.636
970.7.64.64/2970.7.64.65 to 70.7.64.7070.7.64.716
1070.7.64.72/2970.7.64.73 to 70.7.64.7870.7.64.796
1170.7.64.80/2970.7.64.81 to 70.7.64.8670.7.64.876
1270.7.64.88/2970.7.64.89 to 70.7.64.9470.7.64.956
1370.7.64.96/2970.7.64.97 to 70.7.64.10270.7.64.1036
1470.7.64.104/2970.7.64.105 to 70.7.64.11070.7.64.1116
1570.7.64.112/2970.7.64.113 to 70.7.64.11870.7.64.1196
1670.7.64.120/2970.7.64.121 to 70.7.64.12670.7.64.1276
1770.7.64.128/2970.7.64.129 to 70.7.64.13470.7.64.1356
1870.7.64.136/2970.7.64.137 to 70.7.64.14270.7.64.1436
1970.7.64.144/2970.7.64.145 to 70.7.64.15070.7.64.1516
2070.7.64.152/2970.7.64.153 to 70.7.64.15870.7.64.1596
2170.7.64.160/2970.7.64.161 to 70.7.64.16670.7.64.1676
2270.7.64.168/2970.7.64.169 to 70.7.64.17470.7.64.1756
2370.7.64.176/2970.7.64.177 to 70.7.64.18270.7.64.1836
2470.7.64.184/2970.7.64.185 to 70.7.64.19070.7.64.1916
2570.7.64.192/2970.7.64.193 to 70.7.64.19870.7.64.1996
2670.7.64.200/2970.7.64.201 to 70.7.64.20670.7.64.2076
2770.7.64.208/2970.7.64.209 to 70.7.64.21470.7.64.2156
2870.7.64.216/2970.7.64.217 to 70.7.64.22270.7.64.2236
2970.7.64.224/2970.7.64.225 to 70.7.64.23070.7.64.2316
3070.7.64.232/2970.7.64.233 to 70.7.64.23870.7.64.2396
3170.7.64.240/2970.7.64.241 to 70.7.64.24670.7.64.2476
3270.7.64.248/2970.7.64.249 to 70.7.64.25470.7.64.2556
3370.7.65.0/2970.7.65.1 to 70.7.65.670.7.65.76
3470.7.65.8/2970.7.65.9 to 70.7.65.1470.7.65.156
3570.7.65.16/2970.7.65.17 to 70.7.65.2270.7.65.236
3670.7.65.24/2970.7.65.25 to 70.7.65.3070.7.65.316
3770.7.65.32/2970.7.65.33 to 70.7.65.3870.7.65.396
3870.7.65.40/2970.7.65.41 to 70.7.65.4670.7.65.476
3970.7.65.48/2970.7.65.49 to 70.7.65.5470.7.65.556
4070.7.65.56/2970.7.65.57 to 70.7.65.6270.7.65.636
4170.7.65.64/2970.7.65.65 to 70.7.65.7070.7.65.716
4270.7.65.72/2970.7.65.73 to 70.7.65.7870.7.65.796
4370.7.65.80/2970.7.65.81 to 70.7.65.8670.7.65.876
4470.7.65.88/2970.7.65.89 to 70.7.65.9470.7.65.956
4570.7.65.96/2970.7.65.97 to 70.7.65.10270.7.65.1036
4670.7.65.104/2970.7.65.105 to 70.7.65.11070.7.65.1116
4770.7.65.112/2970.7.65.113 to 70.7.65.11870.7.65.1196
4870.7.65.120/2970.7.65.121 to 70.7.65.12670.7.65.1276
4970.7.65.128/2970.7.65.129 to 70.7.65.13470.7.65.1356
5070.7.65.136/2970.7.65.137 to 70.7.65.14270.7.65.1436
5170.7.65.144/2970.7.65.145 to 70.7.65.15070.7.65.1516
5270.7.65.152/2970.7.65.153 to 70.7.65.15870.7.65.1596
5370.7.65.160/2970.7.65.161 to 70.7.65.16670.7.65.1676
5470.7.65.168/2970.7.65.169 to 70.7.65.17470.7.65.1756
5570.7.65.176/2970.7.65.177 to 70.7.65.18270.7.65.1836
5670.7.65.184/2970.7.65.185 to 70.7.65.19070.7.65.1916
5770.7.65.192/2970.7.65.193 to 70.7.65.19870.7.65.1996
5870.7.65.200/2970.7.65.201 to 70.7.65.20670.7.65.2076
5970.7.65.208/2970.7.65.209 to 70.7.65.21470.7.65.2156
6070.7.65.216/2970.7.65.217 to 70.7.65.22270.7.65.2236
6170.7.65.224/2970.7.65.225 to 70.7.65.23070.7.65.2316
6270.7.65.232/2970.7.65.233 to 70.7.65.23870.7.65.2396
6370.7.65.240/2970.7.65.241 to 70.7.65.24670.7.65.2476
6470.7.65.248/2970.7.65.249 to 70.7.65.25470.7.65.2556
6570.7.66.0/2970.7.66.1 to 70.7.66.670.7.66.76
6670.7.66.8/2970.7.66.9 to 70.7.66.1470.7.66.156
6770.7.66.16/2970.7.66.17 to 70.7.66.2270.7.66.236
6870.7.66.24/2970.7.66.25 to 70.7.66.3070.7.66.316
6970.7.66.32/2970.7.66.33 to 70.7.66.3870.7.66.396
7070.7.66.40/2970.7.66.41 to 70.7.66.4670.7.66.476
7170.7.66.48/2970.7.66.49 to 70.7.66.5470.7.66.556
7270.7.66.56/2970.7.66.57 to 70.7.66.6270.7.66.636
7370.7.66.64/2970.7.66.65 to 70.7.66.7070.7.66.716
7470.7.66.72/2970.7.66.73 to 70.7.66.7870.7.66.796
7570.7.66.80/2970.7.66.81 to 70.7.66.8670.7.66.876
7670.7.66.88/2970.7.66.89 to 70.7.66.9470.7.66.956
7770.7.66.96/2970.7.66.97 to 70.7.66.10270.7.66.1036
7870.7.66.104/2970.7.66.105 to 70.7.66.11070.7.66.1116
7970.7.66.112/2970.7.66.113 to 70.7.66.11870.7.66.1196
8070.7.66.120/2970.7.66.121 to 70.7.66.12670.7.66.1276
8170.7.66.128/2970.7.66.129 to 70.7.66.13470.7.66.1356
8270.7.66.136/2970.7.66.137 to 70.7.66.14270.7.66.1436
8370.7.66.144/2970.7.66.145 to 70.7.66.15070.7.66.1516
8470.7.66.152/2970.7.66.153 to 70.7.66.15870.7.66.1596
8570.7.66.160/2970.7.66.161 to 70.7.66.16670.7.66.1676
8670.7.66.168/2970.7.66.169 to 70.7.66.17470.7.66.1756
8770.7.66.176/2970.7.66.177 to 70.7.66.18270.7.66.1836
8870.7.66.184/2970.7.66.185 to 70.7.66.19070.7.66.1916
8970.7.66.192/2970.7.66.193 to 70.7.66.19870.7.66.1996
9070.7.66.200/2970.7.66.201 to 70.7.66.20670.7.66.2076
9170.7.66.208/2970.7.66.209 to 70.7.66.21470.7.66.2156
9270.7.66.216/2970.7.66.217 to 70.7.66.22270.7.66.2236
9370.7.66.224/2970.7.66.225 to 70.7.66.23070.7.66.2316
9470.7.66.232/2970.7.66.233 to 70.7.66.23870.7.66.2396
9570.7.66.240/2970.7.66.241 to 70.7.66.24670.7.66.2476
9670.7.66.248/2970.7.66.249 to 70.7.66.25470.7.66.2556
9770.7.67.0/2970.7.67.1 to 70.7.67.670.7.67.76
9870.7.67.8/2970.7.67.9 to 70.7.67.1470.7.67.156
9970.7.67.16/2970.7.67.17 to 70.7.67.2270.7.67.236
10070.7.67.24/2970.7.67.25 to 70.7.67.3070.7.67.316
10170.7.67.32/2970.7.67.33 to 70.7.67.3870.7.67.396
10270.7.67.40/2970.7.67.41 to 70.7.67.4670.7.67.476
10370.7.67.48/2970.7.67.49 to 70.7.67.5470.7.67.556
10470.7.67.56/2970.7.67.57 to 70.7.67.6270.7.67.636
10570.7.67.64/2970.7.67.65 to 70.7.67.7070.7.67.716
10670.7.67.72/2970.7.67.73 to 70.7.67.7870.7.67.796
10770.7.67.80/2970.7.67.81 to 70.7.67.8670.7.67.876
10870.7.67.88/2970.7.67.89 to 70.7.67.9470.7.67.956
10970.7.67.96/2970.7.67.97 to 70.7.67.10270.7.67.1036
11070.7.67.104/2970.7.67.105 to 70.7.67.11070.7.67.1116
11170.7.67.112/2970.7.67.113 to 70.7.67.11870.7.67.1196
11270.7.67.120/2970.7.67.121 to 70.7.67.12670.7.67.1276
11370.7.67.128/2970.7.67.129 to 70.7.67.13470.7.67.1356
11470.7.67.136/2970.7.67.137 to 70.7.67.14270.7.67.1436
11570.7.67.144/2970.7.67.145 to 70.7.67.15070.7.67.1516
11670.7.67.152/2970.7.67.153 to 70.7.67.15870.7.67.1596
11770.7.67.160/2970.7.67.161 to 70.7.67.16670.7.67.1676
11870.7.67.168/2970.7.67.169 to 70.7.67.17470.7.67.1756
11970.7.67.176/2970.7.67.177 to 70.7.67.18270.7.67.1836
12070.7.67.184/2970.7.67.185 to 70.7.67.19070.7.67.1916
12170.7.67.192/2970.7.67.193 to 70.7.67.19870.7.67.1996
12270.7.67.200/2970.7.67.201 to 70.7.67.20670.7.67.2076
12370.7.67.208/2970.7.67.209 to 70.7.67.21470.7.67.2156
12470.7.67.216/2970.7.67.217 to 70.7.67.22270.7.67.2236
12570.7.67.224/2970.7.67.225 to 70.7.67.23070.7.67.2316
12670.7.67.232/2970.7.67.233 to 70.7.67.23870.7.67.2396
12770.7.67.240/2970.7.67.241 to 70.7.67.24670.7.67.2476
12870.7.67.248/2970.7.67.249 to 70.7.67.25470.7.67.2556
12970.7.68.0/2970.7.68.1 to 70.7.68.670.7.68.76
13070.7.68.8/2970.7.68.9 to 70.7.68.1470.7.68.156
13170.7.68.16/2970.7.68.17 to 70.7.68.2270.7.68.236
13270.7.68.24/2970.7.68.25 to 70.7.68.3070.7.68.316
13370.7.68.32/2970.7.68.33 to 70.7.68.3870.7.68.396
13470.7.68.40/2970.7.68.41 to 70.7.68.4670.7.68.476
13570.7.68.48/2970.7.68.49 to 70.7.68.5470.7.68.556
13670.7.68.56/2970.7.68.57 to 70.7.68.6270.7.68.636
13770.7.68.64/2970.7.68.65 to 70.7.68.7070.7.68.716
13870.7.68.72/2970.7.68.73 to 70.7.68.7870.7.68.796
13970.7.68.80/2970.7.68.81 to 70.7.68.8670.7.68.876
14070.7.68.88/2970.7.68.89 to 70.7.68.9470.7.68.956
14170.7.68.96/2970.7.68.97 to 70.7.68.10270.7.68.1036
14270.7.68.104/2970.7.68.105 to 70.7.68.11070.7.68.1116
14370.7.68.112/2970.7.68.113 to 70.7.68.11870.7.68.1196
14470.7.68.120/2970.7.68.121 to 70.7.68.12670.7.68.1276
14570.7.68.128/2970.7.68.129 to 70.7.68.13470.7.68.1356
14670.7.68.136/2970.7.68.137 to 70.7.68.14270.7.68.1436
14770.7.68.144/2970.7.68.145 to 70.7.68.15070.7.68.1516
14870.7.68.152/2970.7.68.153 to 70.7.68.15870.7.68.1596
14970.7.68.160/2970.7.68.161 to 70.7.68.16670.7.68.1676
15070.7.68.168/2970.7.68.169 to 70.7.68.17470.7.68.1756
15170.7.68.176/2970.7.68.177 to 70.7.68.18270.7.68.1836
15270.7.68.184/2970.7.68.185 to 70.7.68.19070.7.68.1916
15370.7.68.192/2970.7.68.193 to 70.7.68.19870.7.68.1996
15470.7.68.200/2970.7.68.201 to 70.7.68.20670.7.68.2076
15570.7.68.208/2970.7.68.209 to 70.7.68.21470.7.68.2156
15670.7.68.216/2970.7.68.217 to 70.7.68.22270.7.68.2236
15770.7.68.224/2970.7.68.225 to 70.7.68.23070.7.68.2316
15870.7.68.232/2970.7.68.233 to 70.7.68.23870.7.68.2396
15970.7.68.240/2970.7.68.241 to 70.7.68.24670.7.68.2476
16070.7.68.248/2970.7.68.249 to 70.7.68.25470.7.68.2556
16170.7.69.0/2970.7.69.1 to 70.7.69.670.7.69.76
16270.7.69.8/2970.7.69.9 to 70.7.69.1470.7.69.156
16370.7.69.16/2970.7.69.17 to 70.7.69.2270.7.69.236
16470.7.69.24/2970.7.69.25 to 70.7.69.3070.7.69.316
16570.7.69.32/2970.7.69.33 to 70.7.69.3870.7.69.396
16670.7.69.40/2970.7.69.41 to 70.7.69.4670.7.69.476
16770.7.69.48/2970.7.69.49 to 70.7.69.5470.7.69.556
16870.7.69.56/2970.7.69.57 to 70.7.69.6270.7.69.636
16970.7.69.64/2970.7.69.65 to 70.7.69.7070.7.69.716
17070.7.69.72/2970.7.69.73 to 70.7.69.7870.7.69.796
17170.7.69.80/2970.7.69.81 to 70.7.69.8670.7.69.876
17270.7.69.88/2970.7.69.89 to 70.7.69.9470.7.69.956
17370.7.69.96/2970.7.69.97 to 70.7.69.10270.7.69.1036
17470.7.69.104/2970.7.69.105 to 70.7.69.11070.7.69.1116
17570.7.69.112/2970.7.69.113 to 70.7.69.11870.7.69.1196
17670.7.69.120/2970.7.69.121 to 70.7.69.12670.7.69.1276
17770.7.69.128/2970.7.69.129 to 70.7.69.13470.7.69.1356
17870.7.69.136/2970.7.69.137 to 70.7.69.14270.7.69.1436
17970.7.69.144/2970.7.69.145 to 70.7.69.15070.7.69.1516
18070.7.69.152/2970.7.69.153 to 70.7.69.15870.7.69.1596
18170.7.69.160/2970.7.69.161 to 70.7.69.16670.7.69.1676
18270.7.69.168/2970.7.69.169 to 70.7.69.17470.7.69.1756
18370.7.69.176/2970.7.69.177 to 70.7.69.18270.7.69.1836
18470.7.69.184/2970.7.69.185 to 70.7.69.19070.7.69.1916
18570.7.69.192/2970.7.69.193 to 70.7.69.19870.7.69.1996
18670.7.69.200/2970.7.69.201 to 70.7.69.20670.7.69.2076
18770.7.69.208/2970.7.69.209 to 70.7.69.21470.7.69.2156
18870.7.69.216/2970.7.69.217 to 70.7.69.22270.7.69.2236
18970.7.69.224/2970.7.69.225 to 70.7.69.23070.7.69.2316
19070.7.69.232/2970.7.69.233 to 70.7.69.23870.7.69.2396
19170.7.69.240/2970.7.69.241 to 70.7.69.24670.7.69.2476
19270.7.69.248/2970.7.69.249 to 70.7.69.25470.7.69.2556
19370.7.70.0/2970.7.70.1 to 70.7.70.670.7.70.76
19470.7.70.8/2970.7.70.9 to 70.7.70.1470.7.70.156
19570.7.70.16/2970.7.70.17 to 70.7.70.2270.7.70.236
19670.7.70.24/2970.7.70.25 to 70.7.70.3070.7.70.316
19770.7.70.32/2970.7.70.33 to 70.7.70.3870.7.70.396
19870.7.70.40/2970.7.70.41 to 70.7.70.4670.7.70.476
19970.7.70.48/2970.7.70.49 to 70.7.70.5470.7.70.556
20070.7.70.56/2970.7.70.57 to 70.7.70.6270.7.70.636
20170.7.70.64/2970.7.70.65 to 70.7.70.7070.7.70.716
20270.7.70.72/2970.7.70.73 to 70.7.70.7870.7.70.796
20370.7.70.80/2970.7.70.81 to 70.7.70.8670.7.70.876
20470.7.70.88/2970.7.70.89 to 70.7.70.9470.7.70.956
20570.7.70.96/2970.7.70.97 to 70.7.70.10270.7.70.1036
20670.7.70.104/2970.7.70.105 to 70.7.70.11070.7.70.1116
20770.7.70.112/2970.7.70.113 to 70.7.70.11870.7.70.1196
20870.7.70.120/2970.7.70.121 to 70.7.70.12670.7.70.1276
20970.7.70.128/2970.7.70.129 to 70.7.70.13470.7.70.1356
21070.7.70.136/2970.7.70.137 to 70.7.70.14270.7.70.1436
21170.7.70.144/2970.7.70.145 to 70.7.70.15070.7.70.1516
21270.7.70.152/2970.7.70.153 to 70.7.70.15870.7.70.1596
21370.7.70.160/2970.7.70.161 to 70.7.70.16670.7.70.1676
21470.7.70.168/2970.7.70.169 to 70.7.70.17470.7.70.1756
21570.7.70.176/2970.7.70.177 to 70.7.70.18270.7.70.1836
21670.7.70.184/2970.7.70.185 to 70.7.70.19070.7.70.1916
21770.7.70.192/2970.7.70.193 to 70.7.70.19870.7.70.1996
21870.7.70.200/2970.7.70.201 to 70.7.70.20670.7.70.2076
21970.7.70.208/2970.7.70.209 to 70.7.70.21470.7.70.2156
22070.7.70.216/2970.7.70.217 to 70.7.70.22270.7.70.2236
22170.7.70.224/2970.7.70.225 to 70.7.70.23070.7.70.2316
22270.7.70.232/2970.7.70.233 to 70.7.70.23870.7.70.2396
22370.7.70.240/2970.7.70.241 to 70.7.70.24670.7.70.2476
22470.7.70.248/2970.7.70.249 to 70.7.70.25470.7.70.2556
22570.7.71.0/2970.7.71.1 to 70.7.71.670.7.71.76
22670.7.71.8/2970.7.71.9 to 70.7.71.1470.7.71.156
22770.7.71.16/2970.7.71.17 to 70.7.71.2270.7.71.236
22870.7.71.24/2970.7.71.25 to 70.7.71.3070.7.71.316
22970.7.71.32/2970.7.71.33 to 70.7.71.3870.7.71.396
23070.7.71.40/2970.7.71.41 to 70.7.71.4670.7.71.476
23170.7.71.48/2970.7.71.49 to 70.7.71.5470.7.71.556
23270.7.71.56/2970.7.71.57 to 70.7.71.6270.7.71.636
23370.7.71.64/2970.7.71.65 to 70.7.71.7070.7.71.716
23470.7.71.72/2970.7.71.73 to 70.7.71.7870.7.71.796
23570.7.71.80/2970.7.71.81 to 70.7.71.8670.7.71.876
23670.7.71.88/2970.7.71.89 to 70.7.71.9470.7.71.956
23770.7.71.96/2970.7.71.97 to 70.7.71.10270.7.71.1036
23870.7.71.104/2970.7.71.105 to 70.7.71.11070.7.71.1116
23970.7.71.112/2970.7.71.113 to 70.7.71.11870.7.71.1196
24070.7.71.120/2970.7.71.121 to 70.7.71.12670.7.71.1276
24170.7.71.128/2970.7.71.129 to 70.7.71.13470.7.71.1356
24270.7.71.136/2970.7.71.137 to 70.7.71.14270.7.71.1436
24370.7.71.144/2970.7.71.145 to 70.7.71.15070.7.71.1516
24470.7.71.152/2970.7.71.153 to 70.7.71.15870.7.71.1596
24570.7.71.160/2970.7.71.161 to 70.7.71.16670.7.71.1676
24670.7.71.168/2970.7.71.169 to 70.7.71.17470.7.71.1756
24770.7.71.176/2970.7.71.177 to 70.7.71.18270.7.71.1836
24870.7.71.184/2970.7.71.185 to 70.7.71.19070.7.71.1916
24970.7.71.192/2970.7.71.193 to 70.7.71.19870.7.71.1996
25070.7.71.200/2970.7.71.201 to 70.7.71.20670.7.71.2076
25170.7.71.208/2970.7.71.209 to 70.7.71.21470.7.71.2156
25270.7.71.216/2970.7.71.217 to 70.7.71.22270.7.71.2236
25370.7.71.224/2970.7.71.225 to 70.7.71.23070.7.71.2316
25470.7.71.232/2970.7.71.233 to 70.7.71.23870.7.71.2396
25570.7.71.240/2970.7.71.241 to 70.7.71.24670.7.71.2476
25670.7.71.248/2970.7.71.249 to 70.7.71.25470.7.71.2556

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.