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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.

Network28.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
28.0.0.0
Broadcast address
28.255.255.255
First usable
28.0.0.1
Last usable
28.255.255.254
Usable hosts
16,777,214 (16,777,216 less the network and broadcast addresses)
Subnet mask
255.0.0.0
Wildcard mask
0.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/8
Type
Public public
Old class
A (default /8)
As numbers
Hex 1C000000 · Integer 469762048 to 486539263
Reverse DNS zone
28.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00011100..00000000.00000000.0000000028.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network00011100..00000000.00000000.0000000028.0.0.0
Broadcast00011100..11111111.11111111.1111111128.255.255.255
Split into smaller subnets/19
/9 (2)/10 (4)/11 (8)/12 (16)/13 (32)/14 (64)/15 (128)/16 (256)/17 (512)/18 (1,024)/19 (2,048)/20 (4,096)

28.0.0.0/8 makes 2,048 subnets of /19; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
128.0.0.0/1928.0.0.1 to 28.0.31.25428.0.31.2558,190
228.0.32.0/1928.0.32.1 to 28.0.63.25428.0.63.2558,190
328.0.64.0/1928.0.64.1 to 28.0.95.25428.0.95.2558,190
428.0.96.0/1928.0.96.1 to 28.0.127.25428.0.127.2558,190
528.0.128.0/1928.0.128.1 to 28.0.159.25428.0.159.2558,190
628.0.160.0/1928.0.160.1 to 28.0.191.25428.0.191.2558,190
728.0.192.0/1928.0.192.1 to 28.0.223.25428.0.223.2558,190
828.0.224.0/1928.0.224.1 to 28.0.255.25428.0.255.2558,190
928.1.0.0/1928.1.0.1 to 28.1.31.25428.1.31.2558,190
1028.1.32.0/1928.1.32.1 to 28.1.63.25428.1.63.2558,190
1128.1.64.0/1928.1.64.1 to 28.1.95.25428.1.95.2558,190
1228.1.96.0/1928.1.96.1 to 28.1.127.25428.1.127.2558,190
1328.1.128.0/1928.1.128.1 to 28.1.159.25428.1.159.2558,190
1428.1.160.0/1928.1.160.1 to 28.1.191.25428.1.191.2558,190
1528.1.192.0/1928.1.192.1 to 28.1.223.25428.1.223.2558,190
1628.1.224.0/1928.1.224.1 to 28.1.255.25428.1.255.2558,190
1728.2.0.0/1928.2.0.1 to 28.2.31.25428.2.31.2558,190
1828.2.32.0/1928.2.32.1 to 28.2.63.25428.2.63.2558,190
1928.2.64.0/1928.2.64.1 to 28.2.95.25428.2.95.2558,190
2028.2.96.0/1928.2.96.1 to 28.2.127.25428.2.127.2558,190
2128.2.128.0/1928.2.128.1 to 28.2.159.25428.2.159.2558,190
2228.2.160.0/1928.2.160.1 to 28.2.191.25428.2.191.2558,190
2328.2.192.0/1928.2.192.1 to 28.2.223.25428.2.223.2558,190
2428.2.224.0/1928.2.224.1 to 28.2.255.25428.2.255.2558,190
2528.3.0.0/1928.3.0.1 to 28.3.31.25428.3.31.2558,190
2628.3.32.0/1928.3.32.1 to 28.3.63.25428.3.63.2558,190
2728.3.64.0/1928.3.64.1 to 28.3.95.25428.3.95.2558,190
2828.3.96.0/1928.3.96.1 to 28.3.127.25428.3.127.2558,190
2928.3.128.0/1928.3.128.1 to 28.3.159.25428.3.159.2558,190
3028.3.160.0/1928.3.160.1 to 28.3.191.25428.3.191.2558,190
3128.3.192.0/1928.3.192.1 to 28.3.223.25428.3.223.2558,190
3228.3.224.0/1928.3.224.1 to 28.3.255.25428.3.255.2558,190
3328.4.0.0/1928.4.0.1 to 28.4.31.25428.4.31.2558,190
3428.4.32.0/1928.4.32.1 to 28.4.63.25428.4.63.2558,190
3528.4.64.0/1928.4.64.1 to 28.4.95.25428.4.95.2558,190
3628.4.96.0/1928.4.96.1 to 28.4.127.25428.4.127.2558,190
3728.4.128.0/1928.4.128.1 to 28.4.159.25428.4.159.2558,190
3828.4.160.0/1928.4.160.1 to 28.4.191.25428.4.191.2558,190
3928.4.192.0/1928.4.192.1 to 28.4.223.25428.4.223.2558,190
4028.4.224.0/1928.4.224.1 to 28.4.255.25428.4.255.2558,190
4128.5.0.0/1928.5.0.1 to 28.5.31.25428.5.31.2558,190
4228.5.32.0/1928.5.32.1 to 28.5.63.25428.5.63.2558,190
4328.5.64.0/1928.5.64.1 to 28.5.95.25428.5.95.2558,190
4428.5.96.0/1928.5.96.1 to 28.5.127.25428.5.127.2558,190
4528.5.128.0/1928.5.128.1 to 28.5.159.25428.5.159.2558,190
4628.5.160.0/1928.5.160.1 to 28.5.191.25428.5.191.2558,190
4728.5.192.0/1928.5.192.1 to 28.5.223.25428.5.223.2558,190
4828.5.224.0/1928.5.224.1 to 28.5.255.25428.5.255.2558,190
4928.6.0.0/1928.6.0.1 to 28.6.31.25428.6.31.2558,190
5028.6.32.0/1928.6.32.1 to 28.6.63.25428.6.63.2558,190
5128.6.64.0/1928.6.64.1 to 28.6.95.25428.6.95.2558,190
5228.6.96.0/1928.6.96.1 to 28.6.127.25428.6.127.2558,190
5328.6.128.0/1928.6.128.1 to 28.6.159.25428.6.159.2558,190
5428.6.160.0/1928.6.160.1 to 28.6.191.25428.6.191.2558,190
5528.6.192.0/1928.6.192.1 to 28.6.223.25428.6.223.2558,190
5628.6.224.0/1928.6.224.1 to 28.6.255.25428.6.255.2558,190
5728.7.0.0/1928.7.0.1 to 28.7.31.25428.7.31.2558,190
5828.7.32.0/1928.7.32.1 to 28.7.63.25428.7.63.2558,190
5928.7.64.0/1928.7.64.1 to 28.7.95.25428.7.95.2558,190
6028.7.96.0/1928.7.96.1 to 28.7.127.25428.7.127.2558,190
6128.7.128.0/1928.7.128.1 to 28.7.159.25428.7.159.2558,190
6228.7.160.0/1928.7.160.1 to 28.7.191.25428.7.191.2558,190
6328.7.192.0/1928.7.192.1 to 28.7.223.25428.7.223.2558,190
6428.7.224.0/1928.7.224.1 to 28.7.255.25428.7.255.2558,190
6528.8.0.0/1928.8.0.1 to 28.8.31.25428.8.31.2558,190
6628.8.32.0/1928.8.32.1 to 28.8.63.25428.8.63.2558,190
6728.8.64.0/1928.8.64.1 to 28.8.95.25428.8.95.2558,190
6828.8.96.0/1928.8.96.1 to 28.8.127.25428.8.127.2558,190
6928.8.128.0/1928.8.128.1 to 28.8.159.25428.8.159.2558,190
7028.8.160.0/1928.8.160.1 to 28.8.191.25428.8.191.2558,190
7128.8.192.0/1928.8.192.1 to 28.8.223.25428.8.223.2558,190
7228.8.224.0/1928.8.224.1 to 28.8.255.25428.8.255.2558,190
7328.9.0.0/1928.9.0.1 to 28.9.31.25428.9.31.2558,190
7428.9.32.0/1928.9.32.1 to 28.9.63.25428.9.63.2558,190
7528.9.64.0/1928.9.64.1 to 28.9.95.25428.9.95.2558,190
7628.9.96.0/1928.9.96.1 to 28.9.127.25428.9.127.2558,190
7728.9.128.0/1928.9.128.1 to 28.9.159.25428.9.159.2558,190
7828.9.160.0/1928.9.160.1 to 28.9.191.25428.9.191.2558,190
7928.9.192.0/1928.9.192.1 to 28.9.223.25428.9.223.2558,190
8028.9.224.0/1928.9.224.1 to 28.9.255.25428.9.255.2558,190
8128.10.0.0/1928.10.0.1 to 28.10.31.25428.10.31.2558,190
8228.10.32.0/1928.10.32.1 to 28.10.63.25428.10.63.2558,190
8328.10.64.0/1928.10.64.1 to 28.10.95.25428.10.95.2558,190
8428.10.96.0/1928.10.96.1 to 28.10.127.25428.10.127.2558,190
8528.10.128.0/1928.10.128.1 to 28.10.159.25428.10.159.2558,190
8628.10.160.0/1928.10.160.1 to 28.10.191.25428.10.191.2558,190
8728.10.192.0/1928.10.192.1 to 28.10.223.25428.10.223.2558,190
8828.10.224.0/1928.10.224.1 to 28.10.255.25428.10.255.2558,190
8928.11.0.0/1928.11.0.1 to 28.11.31.25428.11.31.2558,190
9028.11.32.0/1928.11.32.1 to 28.11.63.25428.11.63.2558,190
9128.11.64.0/1928.11.64.1 to 28.11.95.25428.11.95.2558,190
9228.11.96.0/1928.11.96.1 to 28.11.127.25428.11.127.2558,190
9328.11.128.0/1928.11.128.1 to 28.11.159.25428.11.159.2558,190
9428.11.160.0/1928.11.160.1 to 28.11.191.25428.11.191.2558,190
9528.11.192.0/1928.11.192.1 to 28.11.223.25428.11.223.2558,190
9628.11.224.0/1928.11.224.1 to 28.11.255.25428.11.255.2558,190
9728.12.0.0/1928.12.0.1 to 28.12.31.25428.12.31.2558,190
9828.12.32.0/1928.12.32.1 to 28.12.63.25428.12.63.2558,190
9928.12.64.0/1928.12.64.1 to 28.12.95.25428.12.95.2558,190
10028.12.96.0/1928.12.96.1 to 28.12.127.25428.12.127.2558,190
10128.12.128.0/1928.12.128.1 to 28.12.159.25428.12.159.2558,190
10228.12.160.0/1928.12.160.1 to 28.12.191.25428.12.191.2558,190
10328.12.192.0/1928.12.192.1 to 28.12.223.25428.12.223.2558,190
10428.12.224.0/1928.12.224.1 to 28.12.255.25428.12.255.2558,190
10528.13.0.0/1928.13.0.1 to 28.13.31.25428.13.31.2558,190
10628.13.32.0/1928.13.32.1 to 28.13.63.25428.13.63.2558,190
10728.13.64.0/1928.13.64.1 to 28.13.95.25428.13.95.2558,190
10828.13.96.0/1928.13.96.1 to 28.13.127.25428.13.127.2558,190
10928.13.128.0/1928.13.128.1 to 28.13.159.25428.13.159.2558,190
11028.13.160.0/1928.13.160.1 to 28.13.191.25428.13.191.2558,190
11128.13.192.0/1928.13.192.1 to 28.13.223.25428.13.223.2558,190
11228.13.224.0/1928.13.224.1 to 28.13.255.25428.13.255.2558,190
11328.14.0.0/1928.14.0.1 to 28.14.31.25428.14.31.2558,190
11428.14.32.0/1928.14.32.1 to 28.14.63.25428.14.63.2558,190
11528.14.64.0/1928.14.64.1 to 28.14.95.25428.14.95.2558,190
11628.14.96.0/1928.14.96.1 to 28.14.127.25428.14.127.2558,190
11728.14.128.0/1928.14.128.1 to 28.14.159.25428.14.159.2558,190
11828.14.160.0/1928.14.160.1 to 28.14.191.25428.14.191.2558,190
11928.14.192.0/1928.14.192.1 to 28.14.223.25428.14.223.2558,190
12028.14.224.0/1928.14.224.1 to 28.14.255.25428.14.255.2558,190
12128.15.0.0/1928.15.0.1 to 28.15.31.25428.15.31.2558,190
12228.15.32.0/1928.15.32.1 to 28.15.63.25428.15.63.2558,190
12328.15.64.0/1928.15.64.1 to 28.15.95.25428.15.95.2558,190
12428.15.96.0/1928.15.96.1 to 28.15.127.25428.15.127.2558,190
12528.15.128.0/1928.15.128.1 to 28.15.159.25428.15.159.2558,190
12628.15.160.0/1928.15.160.1 to 28.15.191.25428.15.191.2558,190
12728.15.192.0/1928.15.192.1 to 28.15.223.25428.15.223.2558,190
12828.15.224.0/1928.15.224.1 to 28.15.255.25428.15.255.2558,190
12928.16.0.0/1928.16.0.1 to 28.16.31.25428.16.31.2558,190
13028.16.32.0/1928.16.32.1 to 28.16.63.25428.16.63.2558,190
13128.16.64.0/1928.16.64.1 to 28.16.95.25428.16.95.2558,190
13228.16.96.0/1928.16.96.1 to 28.16.127.25428.16.127.2558,190
13328.16.128.0/1928.16.128.1 to 28.16.159.25428.16.159.2558,190
13428.16.160.0/1928.16.160.1 to 28.16.191.25428.16.191.2558,190
13528.16.192.0/1928.16.192.1 to 28.16.223.25428.16.223.2558,190
13628.16.224.0/1928.16.224.1 to 28.16.255.25428.16.255.2558,190
13728.17.0.0/1928.17.0.1 to 28.17.31.25428.17.31.2558,190
13828.17.32.0/1928.17.32.1 to 28.17.63.25428.17.63.2558,190
13928.17.64.0/1928.17.64.1 to 28.17.95.25428.17.95.2558,190
14028.17.96.0/1928.17.96.1 to 28.17.127.25428.17.127.2558,190
14128.17.128.0/1928.17.128.1 to 28.17.159.25428.17.159.2558,190
14228.17.160.0/1928.17.160.1 to 28.17.191.25428.17.191.2558,190
14328.17.192.0/1928.17.192.1 to 28.17.223.25428.17.223.2558,190
14428.17.224.0/1928.17.224.1 to 28.17.255.25428.17.255.2558,190
14528.18.0.0/1928.18.0.1 to 28.18.31.25428.18.31.2558,190
14628.18.32.0/1928.18.32.1 to 28.18.63.25428.18.63.2558,190
14728.18.64.0/1928.18.64.1 to 28.18.95.25428.18.95.2558,190
14828.18.96.0/1928.18.96.1 to 28.18.127.25428.18.127.2558,190
14928.18.128.0/1928.18.128.1 to 28.18.159.25428.18.159.2558,190
15028.18.160.0/1928.18.160.1 to 28.18.191.25428.18.191.2558,190
15128.18.192.0/1928.18.192.1 to 28.18.223.25428.18.223.2558,190
15228.18.224.0/1928.18.224.1 to 28.18.255.25428.18.255.2558,190
15328.19.0.0/1928.19.0.1 to 28.19.31.25428.19.31.2558,190
15428.19.32.0/1928.19.32.1 to 28.19.63.25428.19.63.2558,190
15528.19.64.0/1928.19.64.1 to 28.19.95.25428.19.95.2558,190
15628.19.96.0/1928.19.96.1 to 28.19.127.25428.19.127.2558,190
15728.19.128.0/1928.19.128.1 to 28.19.159.25428.19.159.2558,190
15828.19.160.0/1928.19.160.1 to 28.19.191.25428.19.191.2558,190
15928.19.192.0/1928.19.192.1 to 28.19.223.25428.19.223.2558,190
16028.19.224.0/1928.19.224.1 to 28.19.255.25428.19.255.2558,190
16128.20.0.0/1928.20.0.1 to 28.20.31.25428.20.31.2558,190
16228.20.32.0/1928.20.32.1 to 28.20.63.25428.20.63.2558,190
16328.20.64.0/1928.20.64.1 to 28.20.95.25428.20.95.2558,190
16428.20.96.0/1928.20.96.1 to 28.20.127.25428.20.127.2558,190
16528.20.128.0/1928.20.128.1 to 28.20.159.25428.20.159.2558,190
16628.20.160.0/1928.20.160.1 to 28.20.191.25428.20.191.2558,190
16728.20.192.0/1928.20.192.1 to 28.20.223.25428.20.223.2558,190
16828.20.224.0/1928.20.224.1 to 28.20.255.25428.20.255.2558,190
16928.21.0.0/1928.21.0.1 to 28.21.31.25428.21.31.2558,190
17028.21.32.0/1928.21.32.1 to 28.21.63.25428.21.63.2558,190
17128.21.64.0/1928.21.64.1 to 28.21.95.25428.21.95.2558,190
17228.21.96.0/1928.21.96.1 to 28.21.127.25428.21.127.2558,190
17328.21.128.0/1928.21.128.1 to 28.21.159.25428.21.159.2558,190
17428.21.160.0/1928.21.160.1 to 28.21.191.25428.21.191.2558,190
17528.21.192.0/1928.21.192.1 to 28.21.223.25428.21.223.2558,190
17628.21.224.0/1928.21.224.1 to 28.21.255.25428.21.255.2558,190
17728.22.0.0/1928.22.0.1 to 28.22.31.25428.22.31.2558,190
17828.22.32.0/1928.22.32.1 to 28.22.63.25428.22.63.2558,190
17928.22.64.0/1928.22.64.1 to 28.22.95.25428.22.95.2558,190
18028.22.96.0/1928.22.96.1 to 28.22.127.25428.22.127.2558,190
18128.22.128.0/1928.22.128.1 to 28.22.159.25428.22.159.2558,190
18228.22.160.0/1928.22.160.1 to 28.22.191.25428.22.191.2558,190
18328.22.192.0/1928.22.192.1 to 28.22.223.25428.22.223.2558,190
18428.22.224.0/1928.22.224.1 to 28.22.255.25428.22.255.2558,190
18528.23.0.0/1928.23.0.1 to 28.23.31.25428.23.31.2558,190
18628.23.32.0/1928.23.32.1 to 28.23.63.25428.23.63.2558,190
18728.23.64.0/1928.23.64.1 to 28.23.95.25428.23.95.2558,190
18828.23.96.0/1928.23.96.1 to 28.23.127.25428.23.127.2558,190
18928.23.128.0/1928.23.128.1 to 28.23.159.25428.23.159.2558,190
19028.23.160.0/1928.23.160.1 to 28.23.191.25428.23.191.2558,190
19128.23.192.0/1928.23.192.1 to 28.23.223.25428.23.223.2558,190
19228.23.224.0/1928.23.224.1 to 28.23.255.25428.23.255.2558,190
19328.24.0.0/1928.24.0.1 to 28.24.31.25428.24.31.2558,190
19428.24.32.0/1928.24.32.1 to 28.24.63.25428.24.63.2558,190
19528.24.64.0/1928.24.64.1 to 28.24.95.25428.24.95.2558,190
19628.24.96.0/1928.24.96.1 to 28.24.127.25428.24.127.2558,190
19728.24.128.0/1928.24.128.1 to 28.24.159.25428.24.159.2558,190
19828.24.160.0/1928.24.160.1 to 28.24.191.25428.24.191.2558,190
19928.24.192.0/1928.24.192.1 to 28.24.223.25428.24.223.2558,190
20028.24.224.0/1928.24.224.1 to 28.24.255.25428.24.255.2558,190
20128.25.0.0/1928.25.0.1 to 28.25.31.25428.25.31.2558,190
20228.25.32.0/1928.25.32.1 to 28.25.63.25428.25.63.2558,190
20328.25.64.0/1928.25.64.1 to 28.25.95.25428.25.95.2558,190
20428.25.96.0/1928.25.96.1 to 28.25.127.25428.25.127.2558,190
20528.25.128.0/1928.25.128.1 to 28.25.159.25428.25.159.2558,190
20628.25.160.0/1928.25.160.1 to 28.25.191.25428.25.191.2558,190
20728.25.192.0/1928.25.192.1 to 28.25.223.25428.25.223.2558,190
20828.25.224.0/1928.25.224.1 to 28.25.255.25428.25.255.2558,190
20928.26.0.0/1928.26.0.1 to 28.26.31.25428.26.31.2558,190
21028.26.32.0/1928.26.32.1 to 28.26.63.25428.26.63.2558,190
21128.26.64.0/1928.26.64.1 to 28.26.95.25428.26.95.2558,190
21228.26.96.0/1928.26.96.1 to 28.26.127.25428.26.127.2558,190
21328.26.128.0/1928.26.128.1 to 28.26.159.25428.26.159.2558,190
21428.26.160.0/1928.26.160.1 to 28.26.191.25428.26.191.2558,190
21528.26.192.0/1928.26.192.1 to 28.26.223.25428.26.223.2558,190
21628.26.224.0/1928.26.224.1 to 28.26.255.25428.26.255.2558,190
21728.27.0.0/1928.27.0.1 to 28.27.31.25428.27.31.2558,190
21828.27.32.0/1928.27.32.1 to 28.27.63.25428.27.63.2558,190
21928.27.64.0/1928.27.64.1 to 28.27.95.25428.27.95.2558,190
22028.27.96.0/1928.27.96.1 to 28.27.127.25428.27.127.2558,190
22128.27.128.0/1928.27.128.1 to 28.27.159.25428.27.159.2558,190
22228.27.160.0/1928.27.160.1 to 28.27.191.25428.27.191.2558,190
22328.27.192.0/1928.27.192.1 to 28.27.223.25428.27.223.2558,190
22428.27.224.0/1928.27.224.1 to 28.27.255.25428.27.255.2558,190
22528.28.0.0/1928.28.0.1 to 28.28.31.25428.28.31.2558,190
22628.28.32.0/1928.28.32.1 to 28.28.63.25428.28.63.2558,190
22728.28.64.0/1928.28.64.1 to 28.28.95.25428.28.95.2558,190
22828.28.96.0/1928.28.96.1 to 28.28.127.25428.28.127.2558,190
22928.28.128.0/1928.28.128.1 to 28.28.159.25428.28.159.2558,190
23028.28.160.0/1928.28.160.1 to 28.28.191.25428.28.191.2558,190
23128.28.192.0/1928.28.192.1 to 28.28.223.25428.28.223.2558,190
23228.28.224.0/1928.28.224.1 to 28.28.255.25428.28.255.2558,190
23328.29.0.0/1928.29.0.1 to 28.29.31.25428.29.31.2558,190
23428.29.32.0/1928.29.32.1 to 28.29.63.25428.29.63.2558,190
23528.29.64.0/1928.29.64.1 to 28.29.95.25428.29.95.2558,190
23628.29.96.0/1928.29.96.1 to 28.29.127.25428.29.127.2558,190
23728.29.128.0/1928.29.128.1 to 28.29.159.25428.29.159.2558,190
23828.29.160.0/1928.29.160.1 to 28.29.191.25428.29.191.2558,190
23928.29.192.0/1928.29.192.1 to 28.29.223.25428.29.223.2558,190
24028.29.224.0/1928.29.224.1 to 28.29.255.25428.29.255.2558,190
24128.30.0.0/1928.30.0.1 to 28.30.31.25428.30.31.2558,190
24228.30.32.0/1928.30.32.1 to 28.30.63.25428.30.63.2558,190
24328.30.64.0/1928.30.64.1 to 28.30.95.25428.30.95.2558,190
24428.30.96.0/1928.30.96.1 to 28.30.127.25428.30.127.2558,190
24528.30.128.0/1928.30.128.1 to 28.30.159.25428.30.159.2558,190
24628.30.160.0/1928.30.160.1 to 28.30.191.25428.30.191.2558,190
24728.30.192.0/1928.30.192.1 to 28.30.223.25428.30.223.2558,190
24828.30.224.0/1928.30.224.1 to 28.30.255.25428.30.255.2558,190
24928.31.0.0/1928.31.0.1 to 28.31.31.25428.31.31.2558,190
25028.31.32.0/1928.31.32.1 to 28.31.63.25428.31.63.2558,190
25128.31.64.0/1928.31.64.1 to 28.31.95.25428.31.95.2558,190
25228.31.96.0/1928.31.96.1 to 28.31.127.25428.31.127.2558,190
25328.31.128.0/1928.31.128.1 to 28.31.159.25428.31.159.2558,190
25428.31.160.0/1928.31.160.1 to 28.31.191.25428.31.191.2558,190
25528.31.192.0/1928.31.192.1 to 28.31.223.25428.31.223.2558,190
25628.31.224.0/1928.31.224.1 to 28.31.255.25428.31.255.2558,190

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.