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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.

Network45.78.0.0/19
Usable hosts8,190
Subnet mask255.255.224.0
Addresses8,192
Network address
45.78.0.0
Broadcast address
45.78.31.255
First usable
45.78.0.1
Last usable
45.78.31.254
Usable hosts
8,190 (8,192 less the network and broadcast addresses)
Subnet mask
255.255.224.0
Wildcard mask
0.0.31.255 (Cisco ACLs, OSPF)
Prefix length
/19
Type
Public public
Old class
A (default /8)
As numbers
Hex 2D4E0000 · Integer 760086528 to 760094719
Reverse DNS zones
0.78.45.in-addr.arpa
1.78.45.in-addr.arpa
2.78.45.in-addr.arpa
3.78.45.in-addr.arpa
4.78.45.in-addr.arpa
5.78.45.in-addr.arpa
6.78.45.in-addr.arpa
7.78.45.in-addr.arpa
8.78.45.in-addr.arpa
9.78.45.in-addr.arpa
10.78.45.in-addr.arpa
11.78.45.in-addr.arpa
12.78.45.in-addr.arpa
13.78.45.in-addr.arpa
14.78.45.in-addr.arpa
15.78.45.in-addr.arpa
and 16 more
/19 is not on a 8-bit boundary, so it takes 32 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00101101.01001110.00000000.0000000045.78.0.0
Subnet mask11111111.11111111.11100000.00000000255.255.224.0
Network00101101.01001110.00000000.0000000045.78.0.0
Broadcast00101101.01001110.00011111.1111111145.78.31.255
Split into smaller subnets/28
/20 (2)/21 (4)/22 (8)/23 (16)/24 (32)/25 (64)/26 (128)/27 (256)/28 (512)/29 (1,024)/30 (2,048)/31 (4,096)

45.78.0.0/19 makes 512 subnets of /28; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
145.78.0.0/2845.78.0.1 to 45.78.0.1445.78.0.1514
245.78.0.16/2845.78.0.17 to 45.78.0.3045.78.0.3114
345.78.0.32/2845.78.0.33 to 45.78.0.4645.78.0.4714
445.78.0.48/2845.78.0.49 to 45.78.0.6245.78.0.6314
545.78.0.64/2845.78.0.65 to 45.78.0.7845.78.0.7914
645.78.0.80/2845.78.0.81 to 45.78.0.9445.78.0.9514
745.78.0.96/2845.78.0.97 to 45.78.0.11045.78.0.11114
845.78.0.112/2845.78.0.113 to 45.78.0.12645.78.0.12714
945.78.0.128/2845.78.0.129 to 45.78.0.14245.78.0.14314
1045.78.0.144/2845.78.0.145 to 45.78.0.15845.78.0.15914
1145.78.0.160/2845.78.0.161 to 45.78.0.17445.78.0.17514
1245.78.0.176/2845.78.0.177 to 45.78.0.19045.78.0.19114
1345.78.0.192/2845.78.0.193 to 45.78.0.20645.78.0.20714
1445.78.0.208/2845.78.0.209 to 45.78.0.22245.78.0.22314
1545.78.0.224/2845.78.0.225 to 45.78.0.23845.78.0.23914
1645.78.0.240/2845.78.0.241 to 45.78.0.25445.78.0.25514
1745.78.1.0/2845.78.1.1 to 45.78.1.1445.78.1.1514
1845.78.1.16/2845.78.1.17 to 45.78.1.3045.78.1.3114
1945.78.1.32/2845.78.1.33 to 45.78.1.4645.78.1.4714
2045.78.1.48/2845.78.1.49 to 45.78.1.6245.78.1.6314
2145.78.1.64/2845.78.1.65 to 45.78.1.7845.78.1.7914
2245.78.1.80/2845.78.1.81 to 45.78.1.9445.78.1.9514
2345.78.1.96/2845.78.1.97 to 45.78.1.11045.78.1.11114
2445.78.1.112/2845.78.1.113 to 45.78.1.12645.78.1.12714
2545.78.1.128/2845.78.1.129 to 45.78.1.14245.78.1.14314
2645.78.1.144/2845.78.1.145 to 45.78.1.15845.78.1.15914
2745.78.1.160/2845.78.1.161 to 45.78.1.17445.78.1.17514
2845.78.1.176/2845.78.1.177 to 45.78.1.19045.78.1.19114
2945.78.1.192/2845.78.1.193 to 45.78.1.20645.78.1.20714
3045.78.1.208/2845.78.1.209 to 45.78.1.22245.78.1.22314
3145.78.1.224/2845.78.1.225 to 45.78.1.23845.78.1.23914
3245.78.1.240/2845.78.1.241 to 45.78.1.25445.78.1.25514
3345.78.2.0/2845.78.2.1 to 45.78.2.1445.78.2.1514
3445.78.2.16/2845.78.2.17 to 45.78.2.3045.78.2.3114
3545.78.2.32/2845.78.2.33 to 45.78.2.4645.78.2.4714
3645.78.2.48/2845.78.2.49 to 45.78.2.6245.78.2.6314
3745.78.2.64/2845.78.2.65 to 45.78.2.7845.78.2.7914
3845.78.2.80/2845.78.2.81 to 45.78.2.9445.78.2.9514
3945.78.2.96/2845.78.2.97 to 45.78.2.11045.78.2.11114
4045.78.2.112/2845.78.2.113 to 45.78.2.12645.78.2.12714
4145.78.2.128/2845.78.2.129 to 45.78.2.14245.78.2.14314
4245.78.2.144/2845.78.2.145 to 45.78.2.15845.78.2.15914
4345.78.2.160/2845.78.2.161 to 45.78.2.17445.78.2.17514
4445.78.2.176/2845.78.2.177 to 45.78.2.19045.78.2.19114
4545.78.2.192/2845.78.2.193 to 45.78.2.20645.78.2.20714
4645.78.2.208/2845.78.2.209 to 45.78.2.22245.78.2.22314
4745.78.2.224/2845.78.2.225 to 45.78.2.23845.78.2.23914
4845.78.2.240/2845.78.2.241 to 45.78.2.25445.78.2.25514
4945.78.3.0/2845.78.3.1 to 45.78.3.1445.78.3.1514
5045.78.3.16/2845.78.3.17 to 45.78.3.3045.78.3.3114
5145.78.3.32/2845.78.3.33 to 45.78.3.4645.78.3.4714
5245.78.3.48/2845.78.3.49 to 45.78.3.6245.78.3.6314
5345.78.3.64/2845.78.3.65 to 45.78.3.7845.78.3.7914
5445.78.3.80/2845.78.3.81 to 45.78.3.9445.78.3.9514
5545.78.3.96/2845.78.3.97 to 45.78.3.11045.78.3.11114
5645.78.3.112/2845.78.3.113 to 45.78.3.12645.78.3.12714
5745.78.3.128/2845.78.3.129 to 45.78.3.14245.78.3.14314
5845.78.3.144/2845.78.3.145 to 45.78.3.15845.78.3.15914
5945.78.3.160/2845.78.3.161 to 45.78.3.17445.78.3.17514
6045.78.3.176/2845.78.3.177 to 45.78.3.19045.78.3.19114
6145.78.3.192/2845.78.3.193 to 45.78.3.20645.78.3.20714
6245.78.3.208/2845.78.3.209 to 45.78.3.22245.78.3.22314
6345.78.3.224/2845.78.3.225 to 45.78.3.23845.78.3.23914
6445.78.3.240/2845.78.3.241 to 45.78.3.25445.78.3.25514
6545.78.4.0/2845.78.4.1 to 45.78.4.1445.78.4.1514
6645.78.4.16/2845.78.4.17 to 45.78.4.3045.78.4.3114
6745.78.4.32/2845.78.4.33 to 45.78.4.4645.78.4.4714
6845.78.4.48/2845.78.4.49 to 45.78.4.6245.78.4.6314
6945.78.4.64/2845.78.4.65 to 45.78.4.7845.78.4.7914
7045.78.4.80/2845.78.4.81 to 45.78.4.9445.78.4.9514
7145.78.4.96/2845.78.4.97 to 45.78.4.11045.78.4.11114
7245.78.4.112/2845.78.4.113 to 45.78.4.12645.78.4.12714
7345.78.4.128/2845.78.4.129 to 45.78.4.14245.78.4.14314
7445.78.4.144/2845.78.4.145 to 45.78.4.15845.78.4.15914
7545.78.4.160/2845.78.4.161 to 45.78.4.17445.78.4.17514
7645.78.4.176/2845.78.4.177 to 45.78.4.19045.78.4.19114
7745.78.4.192/2845.78.4.193 to 45.78.4.20645.78.4.20714
7845.78.4.208/2845.78.4.209 to 45.78.4.22245.78.4.22314
7945.78.4.224/2845.78.4.225 to 45.78.4.23845.78.4.23914
8045.78.4.240/2845.78.4.241 to 45.78.4.25445.78.4.25514
8145.78.5.0/2845.78.5.1 to 45.78.5.1445.78.5.1514
8245.78.5.16/2845.78.5.17 to 45.78.5.3045.78.5.3114
8345.78.5.32/2845.78.5.33 to 45.78.5.4645.78.5.4714
8445.78.5.48/2845.78.5.49 to 45.78.5.6245.78.5.6314
8545.78.5.64/2845.78.5.65 to 45.78.5.7845.78.5.7914
8645.78.5.80/2845.78.5.81 to 45.78.5.9445.78.5.9514
8745.78.5.96/2845.78.5.97 to 45.78.5.11045.78.5.11114
8845.78.5.112/2845.78.5.113 to 45.78.5.12645.78.5.12714
8945.78.5.128/2845.78.5.129 to 45.78.5.14245.78.5.14314
9045.78.5.144/2845.78.5.145 to 45.78.5.15845.78.5.15914
9145.78.5.160/2845.78.5.161 to 45.78.5.17445.78.5.17514
9245.78.5.176/2845.78.5.177 to 45.78.5.19045.78.5.19114
9345.78.5.192/2845.78.5.193 to 45.78.5.20645.78.5.20714
9445.78.5.208/2845.78.5.209 to 45.78.5.22245.78.5.22314
9545.78.5.224/2845.78.5.225 to 45.78.5.23845.78.5.23914
9645.78.5.240/2845.78.5.241 to 45.78.5.25445.78.5.25514
9745.78.6.0/2845.78.6.1 to 45.78.6.1445.78.6.1514
9845.78.6.16/2845.78.6.17 to 45.78.6.3045.78.6.3114
9945.78.6.32/2845.78.6.33 to 45.78.6.4645.78.6.4714
10045.78.6.48/2845.78.6.49 to 45.78.6.6245.78.6.6314
10145.78.6.64/2845.78.6.65 to 45.78.6.7845.78.6.7914
10245.78.6.80/2845.78.6.81 to 45.78.6.9445.78.6.9514
10345.78.6.96/2845.78.6.97 to 45.78.6.11045.78.6.11114
10445.78.6.112/2845.78.6.113 to 45.78.6.12645.78.6.12714
10545.78.6.128/2845.78.6.129 to 45.78.6.14245.78.6.14314
10645.78.6.144/2845.78.6.145 to 45.78.6.15845.78.6.15914
10745.78.6.160/2845.78.6.161 to 45.78.6.17445.78.6.17514
10845.78.6.176/2845.78.6.177 to 45.78.6.19045.78.6.19114
10945.78.6.192/2845.78.6.193 to 45.78.6.20645.78.6.20714
11045.78.6.208/2845.78.6.209 to 45.78.6.22245.78.6.22314
11145.78.6.224/2845.78.6.225 to 45.78.6.23845.78.6.23914
11245.78.6.240/2845.78.6.241 to 45.78.6.25445.78.6.25514
11345.78.7.0/2845.78.7.1 to 45.78.7.1445.78.7.1514
11445.78.7.16/2845.78.7.17 to 45.78.7.3045.78.7.3114
11545.78.7.32/2845.78.7.33 to 45.78.7.4645.78.7.4714
11645.78.7.48/2845.78.7.49 to 45.78.7.6245.78.7.6314
11745.78.7.64/2845.78.7.65 to 45.78.7.7845.78.7.7914
11845.78.7.80/2845.78.7.81 to 45.78.7.9445.78.7.9514
11945.78.7.96/2845.78.7.97 to 45.78.7.11045.78.7.11114
12045.78.7.112/2845.78.7.113 to 45.78.7.12645.78.7.12714
12145.78.7.128/2845.78.7.129 to 45.78.7.14245.78.7.14314
12245.78.7.144/2845.78.7.145 to 45.78.7.15845.78.7.15914
12345.78.7.160/2845.78.7.161 to 45.78.7.17445.78.7.17514
12445.78.7.176/2845.78.7.177 to 45.78.7.19045.78.7.19114
12545.78.7.192/2845.78.7.193 to 45.78.7.20645.78.7.20714
12645.78.7.208/2845.78.7.209 to 45.78.7.22245.78.7.22314
12745.78.7.224/2845.78.7.225 to 45.78.7.23845.78.7.23914
12845.78.7.240/2845.78.7.241 to 45.78.7.25445.78.7.25514
12945.78.8.0/2845.78.8.1 to 45.78.8.1445.78.8.1514
13045.78.8.16/2845.78.8.17 to 45.78.8.3045.78.8.3114
13145.78.8.32/2845.78.8.33 to 45.78.8.4645.78.8.4714
13245.78.8.48/2845.78.8.49 to 45.78.8.6245.78.8.6314
13345.78.8.64/2845.78.8.65 to 45.78.8.7845.78.8.7914
13445.78.8.80/2845.78.8.81 to 45.78.8.9445.78.8.9514
13545.78.8.96/2845.78.8.97 to 45.78.8.11045.78.8.11114
13645.78.8.112/2845.78.8.113 to 45.78.8.12645.78.8.12714
13745.78.8.128/2845.78.8.129 to 45.78.8.14245.78.8.14314
13845.78.8.144/2845.78.8.145 to 45.78.8.15845.78.8.15914
13945.78.8.160/2845.78.8.161 to 45.78.8.17445.78.8.17514
14045.78.8.176/2845.78.8.177 to 45.78.8.19045.78.8.19114
14145.78.8.192/2845.78.8.193 to 45.78.8.20645.78.8.20714
14245.78.8.208/2845.78.8.209 to 45.78.8.22245.78.8.22314
14345.78.8.224/2845.78.8.225 to 45.78.8.23845.78.8.23914
14445.78.8.240/2845.78.8.241 to 45.78.8.25445.78.8.25514
14545.78.9.0/2845.78.9.1 to 45.78.9.1445.78.9.1514
14645.78.9.16/2845.78.9.17 to 45.78.9.3045.78.9.3114
14745.78.9.32/2845.78.9.33 to 45.78.9.4645.78.9.4714
14845.78.9.48/2845.78.9.49 to 45.78.9.6245.78.9.6314
14945.78.9.64/2845.78.9.65 to 45.78.9.7845.78.9.7914
15045.78.9.80/2845.78.9.81 to 45.78.9.9445.78.9.9514
15145.78.9.96/2845.78.9.97 to 45.78.9.11045.78.9.11114
15245.78.9.112/2845.78.9.113 to 45.78.9.12645.78.9.12714
15345.78.9.128/2845.78.9.129 to 45.78.9.14245.78.9.14314
15445.78.9.144/2845.78.9.145 to 45.78.9.15845.78.9.15914
15545.78.9.160/2845.78.9.161 to 45.78.9.17445.78.9.17514
15645.78.9.176/2845.78.9.177 to 45.78.9.19045.78.9.19114
15745.78.9.192/2845.78.9.193 to 45.78.9.20645.78.9.20714
15845.78.9.208/2845.78.9.209 to 45.78.9.22245.78.9.22314
15945.78.9.224/2845.78.9.225 to 45.78.9.23845.78.9.23914
16045.78.9.240/2845.78.9.241 to 45.78.9.25445.78.9.25514
16145.78.10.0/2845.78.10.1 to 45.78.10.1445.78.10.1514
16245.78.10.16/2845.78.10.17 to 45.78.10.3045.78.10.3114
16345.78.10.32/2845.78.10.33 to 45.78.10.4645.78.10.4714
16445.78.10.48/2845.78.10.49 to 45.78.10.6245.78.10.6314
16545.78.10.64/2845.78.10.65 to 45.78.10.7845.78.10.7914
16645.78.10.80/2845.78.10.81 to 45.78.10.9445.78.10.9514
16745.78.10.96/2845.78.10.97 to 45.78.10.11045.78.10.11114
16845.78.10.112/2845.78.10.113 to 45.78.10.12645.78.10.12714
16945.78.10.128/2845.78.10.129 to 45.78.10.14245.78.10.14314
17045.78.10.144/2845.78.10.145 to 45.78.10.15845.78.10.15914
17145.78.10.160/2845.78.10.161 to 45.78.10.17445.78.10.17514
17245.78.10.176/2845.78.10.177 to 45.78.10.19045.78.10.19114
17345.78.10.192/2845.78.10.193 to 45.78.10.20645.78.10.20714
17445.78.10.208/2845.78.10.209 to 45.78.10.22245.78.10.22314
17545.78.10.224/2845.78.10.225 to 45.78.10.23845.78.10.23914
17645.78.10.240/2845.78.10.241 to 45.78.10.25445.78.10.25514
17745.78.11.0/2845.78.11.1 to 45.78.11.1445.78.11.1514
17845.78.11.16/2845.78.11.17 to 45.78.11.3045.78.11.3114
17945.78.11.32/2845.78.11.33 to 45.78.11.4645.78.11.4714
18045.78.11.48/2845.78.11.49 to 45.78.11.6245.78.11.6314
18145.78.11.64/2845.78.11.65 to 45.78.11.7845.78.11.7914
18245.78.11.80/2845.78.11.81 to 45.78.11.9445.78.11.9514
18345.78.11.96/2845.78.11.97 to 45.78.11.11045.78.11.11114
18445.78.11.112/2845.78.11.113 to 45.78.11.12645.78.11.12714
18545.78.11.128/2845.78.11.129 to 45.78.11.14245.78.11.14314
18645.78.11.144/2845.78.11.145 to 45.78.11.15845.78.11.15914
18745.78.11.160/2845.78.11.161 to 45.78.11.17445.78.11.17514
18845.78.11.176/2845.78.11.177 to 45.78.11.19045.78.11.19114
18945.78.11.192/2845.78.11.193 to 45.78.11.20645.78.11.20714
19045.78.11.208/2845.78.11.209 to 45.78.11.22245.78.11.22314
19145.78.11.224/2845.78.11.225 to 45.78.11.23845.78.11.23914
19245.78.11.240/2845.78.11.241 to 45.78.11.25445.78.11.25514
19345.78.12.0/2845.78.12.1 to 45.78.12.1445.78.12.1514
19445.78.12.16/2845.78.12.17 to 45.78.12.3045.78.12.3114
19545.78.12.32/2845.78.12.33 to 45.78.12.4645.78.12.4714
19645.78.12.48/2845.78.12.49 to 45.78.12.6245.78.12.6314
19745.78.12.64/2845.78.12.65 to 45.78.12.7845.78.12.7914
19845.78.12.80/2845.78.12.81 to 45.78.12.9445.78.12.9514
19945.78.12.96/2845.78.12.97 to 45.78.12.11045.78.12.11114
20045.78.12.112/2845.78.12.113 to 45.78.12.12645.78.12.12714
20145.78.12.128/2845.78.12.129 to 45.78.12.14245.78.12.14314
20245.78.12.144/2845.78.12.145 to 45.78.12.15845.78.12.15914
20345.78.12.160/2845.78.12.161 to 45.78.12.17445.78.12.17514
20445.78.12.176/2845.78.12.177 to 45.78.12.19045.78.12.19114
20545.78.12.192/2845.78.12.193 to 45.78.12.20645.78.12.20714
20645.78.12.208/2845.78.12.209 to 45.78.12.22245.78.12.22314
20745.78.12.224/2845.78.12.225 to 45.78.12.23845.78.12.23914
20845.78.12.240/2845.78.12.241 to 45.78.12.25445.78.12.25514
20945.78.13.0/2845.78.13.1 to 45.78.13.1445.78.13.1514
21045.78.13.16/2845.78.13.17 to 45.78.13.3045.78.13.3114
21145.78.13.32/2845.78.13.33 to 45.78.13.4645.78.13.4714
21245.78.13.48/2845.78.13.49 to 45.78.13.6245.78.13.6314
21345.78.13.64/2845.78.13.65 to 45.78.13.7845.78.13.7914
21445.78.13.80/2845.78.13.81 to 45.78.13.9445.78.13.9514
21545.78.13.96/2845.78.13.97 to 45.78.13.11045.78.13.11114
21645.78.13.112/2845.78.13.113 to 45.78.13.12645.78.13.12714
21745.78.13.128/2845.78.13.129 to 45.78.13.14245.78.13.14314
21845.78.13.144/2845.78.13.145 to 45.78.13.15845.78.13.15914
21945.78.13.160/2845.78.13.161 to 45.78.13.17445.78.13.17514
22045.78.13.176/2845.78.13.177 to 45.78.13.19045.78.13.19114
22145.78.13.192/2845.78.13.193 to 45.78.13.20645.78.13.20714
22245.78.13.208/2845.78.13.209 to 45.78.13.22245.78.13.22314
22345.78.13.224/2845.78.13.225 to 45.78.13.23845.78.13.23914
22445.78.13.240/2845.78.13.241 to 45.78.13.25445.78.13.25514
22545.78.14.0/2845.78.14.1 to 45.78.14.1445.78.14.1514
22645.78.14.16/2845.78.14.17 to 45.78.14.3045.78.14.3114
22745.78.14.32/2845.78.14.33 to 45.78.14.4645.78.14.4714
22845.78.14.48/2845.78.14.49 to 45.78.14.6245.78.14.6314
22945.78.14.64/2845.78.14.65 to 45.78.14.7845.78.14.7914
23045.78.14.80/2845.78.14.81 to 45.78.14.9445.78.14.9514
23145.78.14.96/2845.78.14.97 to 45.78.14.11045.78.14.11114
23245.78.14.112/2845.78.14.113 to 45.78.14.12645.78.14.12714
23345.78.14.128/2845.78.14.129 to 45.78.14.14245.78.14.14314
23445.78.14.144/2845.78.14.145 to 45.78.14.15845.78.14.15914
23545.78.14.160/2845.78.14.161 to 45.78.14.17445.78.14.17514
23645.78.14.176/2845.78.14.177 to 45.78.14.19045.78.14.19114
23745.78.14.192/2845.78.14.193 to 45.78.14.20645.78.14.20714
23845.78.14.208/2845.78.14.209 to 45.78.14.22245.78.14.22314
23945.78.14.224/2845.78.14.225 to 45.78.14.23845.78.14.23914
24045.78.14.240/2845.78.14.241 to 45.78.14.25445.78.14.25514
24145.78.15.0/2845.78.15.1 to 45.78.15.1445.78.15.1514
24245.78.15.16/2845.78.15.17 to 45.78.15.3045.78.15.3114
24345.78.15.32/2845.78.15.33 to 45.78.15.4645.78.15.4714
24445.78.15.48/2845.78.15.49 to 45.78.15.6245.78.15.6314
24545.78.15.64/2845.78.15.65 to 45.78.15.7845.78.15.7914
24645.78.15.80/2845.78.15.81 to 45.78.15.9445.78.15.9514
24745.78.15.96/2845.78.15.97 to 45.78.15.11045.78.15.11114
24845.78.15.112/2845.78.15.113 to 45.78.15.12645.78.15.12714
24945.78.15.128/2845.78.15.129 to 45.78.15.14245.78.15.14314
25045.78.15.144/2845.78.15.145 to 45.78.15.15845.78.15.15914
25145.78.15.160/2845.78.15.161 to 45.78.15.17445.78.15.17514
25245.78.15.176/2845.78.15.177 to 45.78.15.19045.78.15.19114
25345.78.15.192/2845.78.15.193 to 45.78.15.20645.78.15.20714
25445.78.15.208/2845.78.15.209 to 45.78.15.22245.78.15.22314
25545.78.15.224/2845.78.15.225 to 45.78.15.23845.78.15.23914
25645.78.15.240/2845.78.15.241 to 45.78.15.25445.78.15.25514

IPv4 CIDR reference (/0 to /32)

IPv4 prefix lengths
PrefixSubnet maskWildcardAddressesUsable hostsSizeTypical use
/00.0.0.0255.255.255.2554,294,967,2964,294,967,29416,777,216 × /24
/1128.0.0.0127.255.255.2552,147,483,6482,147,483,6468,388,608 × /24
/2192.0.0.063.255.255.2551,073,741,8241,073,741,8224,194,304 × /24
/3224.0.0.031.255.255.255536,870,912536,870,9102,097,152 × /24
/4240.0.0.015.255.255.255268,435,456268,435,4541,048,576 × /24
/5248.0.0.07.255.255.255134,217,728134,217,726524,288 × /24
/6252.0.0.03.255.255.25567,108,86467,108,862262,144 × /24
/7254.0.0.01.255.255.25533,554,43233,554,430131,072 × /24
/8255.0.0.00.255.255.25516,777,21616,777,21465,536 × /24Old class A; 10.0.0.0/8
/9255.128.0.00.127.255.2558,388,6088,388,60632,768 × /24
/10255.192.0.00.63.255.2554,194,3044,194,30216,384 × /24
/11255.224.0.00.31.255.2552,097,1522,097,1508,192 × /24
/12255.240.0.00.15.255.2551,048,5761,048,5744,096 × /24172.16.0.0/12
/13255.248.0.00.7.255.255524,288524,2862,048 × /24
/14255.252.0.00.3.255.255262,144262,1421,024 × /24
/15255.254.0.00.1.255.255131,072131,070512 × /24
/16255.255.0.00.0.255.25565,53665,534256 × /24Old class B; 192.168.0.0/16
/17255.255.128.00.0.127.25532,76832,766128 × /24
/18255.255.192.00.0.63.25516,38416,38264 × /24
/19255.255.224.00.0.31.2558,1928,19032 × /24
/20255.255.240.00.0.15.2554,0964,09416 × /24
/21255.255.248.00.0.7.2552,0482,0468 × /24
/22255.255.252.00.0.3.2551,0241,0224 × /24Large office or guest Wi-Fi (1,022 hosts)
/23255.255.254.00.0.1.2555125102 × /24Larger office LAN (510 hosts)
/24255.255.255.00.0.0.2552562541 × /24Typical office LAN (old class C)
/25255.255.255.1280.0.0.1271281261/2 of a /24Smaller LAN or VLAN
/26255.255.255.1920.0.0.6364621/4 of a /24Smaller LAN or VLAN
/27255.255.255.2240.0.0.3132301/8 of a /24Small VLAN, phones, cameras
/28255.255.255.2400.0.0.1516141/16 of a /24Small VLAN, phones, cameras
/29255.255.255.2480.0.0.7861/32 of a /24Small fixed public block (5 usable)
/30255.255.255.2520.0.0.3421/64 of a /24Point-to-point (old style)
/31255.255.255.2540.0.0.1221/128 of a /24Point-to-point link (RFC 3021)
/32255.255.255.2550.0.0.0111/256 of a /24One host

IPv6 prefix reference

IPv6 prefix lengths
PrefixAddresses/64 LANs/48 sitesNibbleTypical use
/342,535,295,865,117,307,932,921,825,928,971,026,432 (2^125)2,305,843,009,213,693,95235,184,372,088,832NoAll global unicast (2000::/3)
/165,192,296,858,534,827,628,530,496,329,220,096 (2^112)281,474,976,710,6564,294,967,296Yes
/20324,518,553,658,426,726,783,156,020,576,256 (2^108)17,592,186,044,416268,435,456YesLarge provider allocation (RIPE minimum for some)
/29633,825,300,114,114,700,748,351,602,688 (2^99)34,359,738,368524,288NoRIPE allocation to a provider (often)
/3279,228,162,514,264,337,593,543,950,336 (2^96)4,294,967,29665,536YesProvider allocation (RIPE default)
/364,951,760,157,141,521,099,596,496,896 (2^92)268,435,4564,096Yes
/40309,485,009,821,345,068,724,781,056 (2^88)16,777,216256Yes
/4419,342,813,113,834,066,795,298,816 (2^84)1,048,57616Yes
/481,208,925,819,614,629,174,706,176 (2^80)65,5361YesOne site or organisation (RIPE PI / assignment)
/5275,557,863,725,914,323,419,136 (2^76)4,096Yes
/564,722,366,482,869,645,213,696 (2^72)256YesSmall site or home (common provider assignment)
/60295,147,905,179,352,825,856 (2^68)16YesSome home broadband (16 LANs)
/6418,446,744,073,709,551,616 (2^64)1YesOne LAN or VLAN (needed for SLAAC)
/7272,057,594,037,927,936 (2^56)1/256 of a /64Yes
/80281,474,976,710,656 (2^48)1/65,536 of a /64Yes
/964,294,967,2961/4,294,967,296 of a /64YesEmbeds an IPv4 address (NAT64)
/11265,5361/281,474,976,710,656 of a /64Yes
/1202561/72,057,594,037,927,936 of a /64Yes
/124161/1,152,921,504,606,846,976 of a /64Yes
/12641/4,611,686,018,427,387,904 of a /64No
/12721/9,223,372,036,854,775,808 of a /64NoPoint-to-point link (RFC 6164)
/12811/18,446,744,073,709,551,616 of a /64YesOne host or loopback

Private and special ranges

IPv4

Special-purpose ranges
RangeNameWhat it is
255.255.255.255/32Limited broadcastEvery host on the local network
0.0.0.0/8This networkNot routed; 0.0.0.0 means "any address" in settings
10.0.0.0/8Private (RFC 1918)Office and home networks; not routed on the internet
100.64.0.0/10Shared address space (CGNAT)Used by providers behind carrier-grade NAT (RFC 6598)
127.0.0.0/8LoopbackThis computer
169.254.0.0/16Link-local (APIPA)Self-assigned when no DHCP server answers
172.16.0.0/12Private (RFC 1918)Office and home networks; not routed on the internet
192.0.0.0/24IETF protocol assignmentsSpecial uses such as DS-Lite
192.0.2.0/24Documentation (TEST-NET-1)For examples; never used on a network
192.88.99.0/246to4 relay (deprecated)Formerly anycast for 6to4
192.168.0.0/16Private (RFC 1918)Office and home networks; not routed on the internet
198.18.0.0/15BenchmarkingNetwork equipment testing (RFC 2544)
198.51.100.0/24Documentation (TEST-NET-2)For examples; never used on a network
203.0.113.0/24Documentation (TEST-NET-3)For examples; never used on a network
224.0.0.0/4MulticastOne-to-many traffic, such as IPTV and routing protocols
240.0.0.0/4ReservedFuture use; not usable on most systems

IPv6

Special-purpose ranges
RangeNameWhat it is
::/128UnspecifiedNo address; :: means "any address" in settings
::1/128LoopbackThis computer
::ffff:0:0/96IPv4-mappedAn IPv4 address written as IPv6
64:ff9b::/96NAT64IPv4 addresses reached through a NAT64 gateway
100::/64Discard onlyTraffic sent here is dropped (RFC 6666)
2001:db8::/32DocumentationFor examples; never used on a network
2001::/32TeredoIPv6 tunnelled over IPv4 UDP
2002::/166to4IPv6 tunnelled over IPv4 (largely retired)
3fff::/20DocumentationFor examples (RFC 9637)
fc00::/7Unique local (ULA)Private IPv6, like RFC 1918; usually fd00::/8
fe80::/10Link-localEvery IPv6 interface has one; not routed
ff00::/8MulticastOne-to-many traffic; replaces broadcast
2000::/3Global unicastPublic internet addresses

About this tool

A network is written as an address and a prefix length, such as 192.168.1.0/24: the first 24 bits name the network and the rest number the devices on it. The calculator works out where the network starts and ends, how many devices it holds, its subnet and wildcard masks, and the reverse DNS zone to ask your provider for.

It also splits a network into equal smaller ones (one per VLAN or site), turns a range of addresses into the fewest CIDR blocks for a firewall rule, and lists every IPv4 prefix length and the common IPv6 ones in reference tables.

Common questions

Why are two addresses lost in every IPv4 subnet?

The first address names the network and the last is the broadcast address, so a /24 has 256 addresses but 254 for devices. A /31 (a link between two routers) and a /32 (one host) are the exceptions.

What size of IPv6 network should a LAN use?

Always /64. Devices pick their own address within it (SLAAC), which needs the full 64 bits. A site usually gets a /48 or /56 from its provider, which holds 65,536 or 256 LANs.

What is a wildcard mask?

The subnet mask turned inside out: 255.255.255.0 becomes 0.0.0.255. Cisco access lists and OSPF use it to say which bits must match.

Which ranges can I use inside an office?

IPv4: 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16. IPv6: unique local addresses from fd00::/8, though most networks use the public prefix from their provider.