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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.

Network28.0.0.0/9
Usable hosts8,388,606
Subnet mask255.128.0.0
Addresses8,388,608
Network address
28.0.0.0
Broadcast address
28.127.255.255
First usable
28.0.0.1
Last usable
28.127.255.254
Usable hosts
8,388,606 (8,388,608 less the network and broadcast addresses)
Subnet mask
255.128.0.0
Wildcard mask
0.127.255.255 (Cisco ACLs, OSPF)
Prefix length
/9
Type
Public public
Old class
A (default /8)
As numbers
Hex 1C000000 · Integer 469762048 to 478150655
Reverse DNS zones
0.28.in-addr.arpa
1.28.in-addr.arpa
2.28.in-addr.arpa
3.28.in-addr.arpa
4.28.in-addr.arpa
5.28.in-addr.arpa
6.28.in-addr.arpa
7.28.in-addr.arpa
8.28.in-addr.arpa
9.28.in-addr.arpa
10.28.in-addr.arpa
11.28.in-addr.arpa
12.28.in-addr.arpa
13.28.in-addr.arpa
14.28.in-addr.arpa
15.28.in-addr.arpa
and 112 more
/9 is not on a 8-bit boundary, so it takes 128 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00011100.00000000.00000000.0000000028.0.0.0
Subnet mask11111111.10000000.00000000.00000000255.128.0.0
Network00011100.00000000.00000000.0000000028.0.0.0
Broadcast00011100.01111111.11111111.1111111128.127.255.255
Split into smaller subnets/20
/10 (2)/11 (4)/12 (8)/13 (16)/14 (32)/15 (64)/16 (128)/17 (256)/18 (512)/19 (1,024)/20 (2,048)/21 (4,096)

28.0.0.0/9 makes 2,048 subnets of /20; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
128.0.0.0/2028.0.0.1 to 28.0.15.25428.0.15.2554,094
228.0.16.0/2028.0.16.1 to 28.0.31.25428.0.31.2554,094
328.0.32.0/2028.0.32.1 to 28.0.47.25428.0.47.2554,094
428.0.48.0/2028.0.48.1 to 28.0.63.25428.0.63.2554,094
528.0.64.0/2028.0.64.1 to 28.0.79.25428.0.79.2554,094
628.0.80.0/2028.0.80.1 to 28.0.95.25428.0.95.2554,094
728.0.96.0/2028.0.96.1 to 28.0.111.25428.0.111.2554,094
828.0.112.0/2028.0.112.1 to 28.0.127.25428.0.127.2554,094
928.0.128.0/2028.0.128.1 to 28.0.143.25428.0.143.2554,094
1028.0.144.0/2028.0.144.1 to 28.0.159.25428.0.159.2554,094
1128.0.160.0/2028.0.160.1 to 28.0.175.25428.0.175.2554,094
1228.0.176.0/2028.0.176.1 to 28.0.191.25428.0.191.2554,094
1328.0.192.0/2028.0.192.1 to 28.0.207.25428.0.207.2554,094
1428.0.208.0/2028.0.208.1 to 28.0.223.25428.0.223.2554,094
1528.0.224.0/2028.0.224.1 to 28.0.239.25428.0.239.2554,094
1628.0.240.0/2028.0.240.1 to 28.0.255.25428.0.255.2554,094
1728.1.0.0/2028.1.0.1 to 28.1.15.25428.1.15.2554,094
1828.1.16.0/2028.1.16.1 to 28.1.31.25428.1.31.2554,094
1928.1.32.0/2028.1.32.1 to 28.1.47.25428.1.47.2554,094
2028.1.48.0/2028.1.48.1 to 28.1.63.25428.1.63.2554,094
2128.1.64.0/2028.1.64.1 to 28.1.79.25428.1.79.2554,094
2228.1.80.0/2028.1.80.1 to 28.1.95.25428.1.95.2554,094
2328.1.96.0/2028.1.96.1 to 28.1.111.25428.1.111.2554,094
2428.1.112.0/2028.1.112.1 to 28.1.127.25428.1.127.2554,094
2528.1.128.0/2028.1.128.1 to 28.1.143.25428.1.143.2554,094
2628.1.144.0/2028.1.144.1 to 28.1.159.25428.1.159.2554,094
2728.1.160.0/2028.1.160.1 to 28.1.175.25428.1.175.2554,094
2828.1.176.0/2028.1.176.1 to 28.1.191.25428.1.191.2554,094
2928.1.192.0/2028.1.192.1 to 28.1.207.25428.1.207.2554,094
3028.1.208.0/2028.1.208.1 to 28.1.223.25428.1.223.2554,094
3128.1.224.0/2028.1.224.1 to 28.1.239.25428.1.239.2554,094
3228.1.240.0/2028.1.240.1 to 28.1.255.25428.1.255.2554,094
3328.2.0.0/2028.2.0.1 to 28.2.15.25428.2.15.2554,094
3428.2.16.0/2028.2.16.1 to 28.2.31.25428.2.31.2554,094
3528.2.32.0/2028.2.32.1 to 28.2.47.25428.2.47.2554,094
3628.2.48.0/2028.2.48.1 to 28.2.63.25428.2.63.2554,094
3728.2.64.0/2028.2.64.1 to 28.2.79.25428.2.79.2554,094
3828.2.80.0/2028.2.80.1 to 28.2.95.25428.2.95.2554,094
3928.2.96.0/2028.2.96.1 to 28.2.111.25428.2.111.2554,094
4028.2.112.0/2028.2.112.1 to 28.2.127.25428.2.127.2554,094
4128.2.128.0/2028.2.128.1 to 28.2.143.25428.2.143.2554,094
4228.2.144.0/2028.2.144.1 to 28.2.159.25428.2.159.2554,094
4328.2.160.0/2028.2.160.1 to 28.2.175.25428.2.175.2554,094
4428.2.176.0/2028.2.176.1 to 28.2.191.25428.2.191.2554,094
4528.2.192.0/2028.2.192.1 to 28.2.207.25428.2.207.2554,094
4628.2.208.0/2028.2.208.1 to 28.2.223.25428.2.223.2554,094
4728.2.224.0/2028.2.224.1 to 28.2.239.25428.2.239.2554,094
4828.2.240.0/2028.2.240.1 to 28.2.255.25428.2.255.2554,094
4928.3.0.0/2028.3.0.1 to 28.3.15.25428.3.15.2554,094
5028.3.16.0/2028.3.16.1 to 28.3.31.25428.3.31.2554,094
5128.3.32.0/2028.3.32.1 to 28.3.47.25428.3.47.2554,094
5228.3.48.0/2028.3.48.1 to 28.3.63.25428.3.63.2554,094
5328.3.64.0/2028.3.64.1 to 28.3.79.25428.3.79.2554,094
5428.3.80.0/2028.3.80.1 to 28.3.95.25428.3.95.2554,094
5528.3.96.0/2028.3.96.1 to 28.3.111.25428.3.111.2554,094
5628.3.112.0/2028.3.112.1 to 28.3.127.25428.3.127.2554,094
5728.3.128.0/2028.3.128.1 to 28.3.143.25428.3.143.2554,094
5828.3.144.0/2028.3.144.1 to 28.3.159.25428.3.159.2554,094
5928.3.160.0/2028.3.160.1 to 28.3.175.25428.3.175.2554,094
6028.3.176.0/2028.3.176.1 to 28.3.191.25428.3.191.2554,094
6128.3.192.0/2028.3.192.1 to 28.3.207.25428.3.207.2554,094
6228.3.208.0/2028.3.208.1 to 28.3.223.25428.3.223.2554,094
6328.3.224.0/2028.3.224.1 to 28.3.239.25428.3.239.2554,094
6428.3.240.0/2028.3.240.1 to 28.3.255.25428.3.255.2554,094
6528.4.0.0/2028.4.0.1 to 28.4.15.25428.4.15.2554,094
6628.4.16.0/2028.4.16.1 to 28.4.31.25428.4.31.2554,094
6728.4.32.0/2028.4.32.1 to 28.4.47.25428.4.47.2554,094
6828.4.48.0/2028.4.48.1 to 28.4.63.25428.4.63.2554,094
6928.4.64.0/2028.4.64.1 to 28.4.79.25428.4.79.2554,094
7028.4.80.0/2028.4.80.1 to 28.4.95.25428.4.95.2554,094
7128.4.96.0/2028.4.96.1 to 28.4.111.25428.4.111.2554,094
7228.4.112.0/2028.4.112.1 to 28.4.127.25428.4.127.2554,094
7328.4.128.0/2028.4.128.1 to 28.4.143.25428.4.143.2554,094
7428.4.144.0/2028.4.144.1 to 28.4.159.25428.4.159.2554,094
7528.4.160.0/2028.4.160.1 to 28.4.175.25428.4.175.2554,094
7628.4.176.0/2028.4.176.1 to 28.4.191.25428.4.191.2554,094
7728.4.192.0/2028.4.192.1 to 28.4.207.25428.4.207.2554,094
7828.4.208.0/2028.4.208.1 to 28.4.223.25428.4.223.2554,094
7928.4.224.0/2028.4.224.1 to 28.4.239.25428.4.239.2554,094
8028.4.240.0/2028.4.240.1 to 28.4.255.25428.4.255.2554,094
8128.5.0.0/2028.5.0.1 to 28.5.15.25428.5.15.2554,094
8228.5.16.0/2028.5.16.1 to 28.5.31.25428.5.31.2554,094
8328.5.32.0/2028.5.32.1 to 28.5.47.25428.5.47.2554,094
8428.5.48.0/2028.5.48.1 to 28.5.63.25428.5.63.2554,094
8528.5.64.0/2028.5.64.1 to 28.5.79.25428.5.79.2554,094
8628.5.80.0/2028.5.80.1 to 28.5.95.25428.5.95.2554,094
8728.5.96.0/2028.5.96.1 to 28.5.111.25428.5.111.2554,094
8828.5.112.0/2028.5.112.1 to 28.5.127.25428.5.127.2554,094
8928.5.128.0/2028.5.128.1 to 28.5.143.25428.5.143.2554,094
9028.5.144.0/2028.5.144.1 to 28.5.159.25428.5.159.2554,094
9128.5.160.0/2028.5.160.1 to 28.5.175.25428.5.175.2554,094
9228.5.176.0/2028.5.176.1 to 28.5.191.25428.5.191.2554,094
9328.5.192.0/2028.5.192.1 to 28.5.207.25428.5.207.2554,094
9428.5.208.0/2028.5.208.1 to 28.5.223.25428.5.223.2554,094
9528.5.224.0/2028.5.224.1 to 28.5.239.25428.5.239.2554,094
9628.5.240.0/2028.5.240.1 to 28.5.255.25428.5.255.2554,094
9728.6.0.0/2028.6.0.1 to 28.6.15.25428.6.15.2554,094
9828.6.16.0/2028.6.16.1 to 28.6.31.25428.6.31.2554,094
9928.6.32.0/2028.6.32.1 to 28.6.47.25428.6.47.2554,094
10028.6.48.0/2028.6.48.1 to 28.6.63.25428.6.63.2554,094
10128.6.64.0/2028.6.64.1 to 28.6.79.25428.6.79.2554,094
10228.6.80.0/2028.6.80.1 to 28.6.95.25428.6.95.2554,094
10328.6.96.0/2028.6.96.1 to 28.6.111.25428.6.111.2554,094
10428.6.112.0/2028.6.112.1 to 28.6.127.25428.6.127.2554,094
10528.6.128.0/2028.6.128.1 to 28.6.143.25428.6.143.2554,094
10628.6.144.0/2028.6.144.1 to 28.6.159.25428.6.159.2554,094
10728.6.160.0/2028.6.160.1 to 28.6.175.25428.6.175.2554,094
10828.6.176.0/2028.6.176.1 to 28.6.191.25428.6.191.2554,094
10928.6.192.0/2028.6.192.1 to 28.6.207.25428.6.207.2554,094
11028.6.208.0/2028.6.208.1 to 28.6.223.25428.6.223.2554,094
11128.6.224.0/2028.6.224.1 to 28.6.239.25428.6.239.2554,094
11228.6.240.0/2028.6.240.1 to 28.6.255.25428.6.255.2554,094
11328.7.0.0/2028.7.0.1 to 28.7.15.25428.7.15.2554,094
11428.7.16.0/2028.7.16.1 to 28.7.31.25428.7.31.2554,094
11528.7.32.0/2028.7.32.1 to 28.7.47.25428.7.47.2554,094
11628.7.48.0/2028.7.48.1 to 28.7.63.25428.7.63.2554,094
11728.7.64.0/2028.7.64.1 to 28.7.79.25428.7.79.2554,094
11828.7.80.0/2028.7.80.1 to 28.7.95.25428.7.95.2554,094
11928.7.96.0/2028.7.96.1 to 28.7.111.25428.7.111.2554,094
12028.7.112.0/2028.7.112.1 to 28.7.127.25428.7.127.2554,094
12128.7.128.0/2028.7.128.1 to 28.7.143.25428.7.143.2554,094
12228.7.144.0/2028.7.144.1 to 28.7.159.25428.7.159.2554,094
12328.7.160.0/2028.7.160.1 to 28.7.175.25428.7.175.2554,094
12428.7.176.0/2028.7.176.1 to 28.7.191.25428.7.191.2554,094
12528.7.192.0/2028.7.192.1 to 28.7.207.25428.7.207.2554,094
12628.7.208.0/2028.7.208.1 to 28.7.223.25428.7.223.2554,094
12728.7.224.0/2028.7.224.1 to 28.7.239.25428.7.239.2554,094
12828.7.240.0/2028.7.240.1 to 28.7.255.25428.7.255.2554,094
12928.8.0.0/2028.8.0.1 to 28.8.15.25428.8.15.2554,094
13028.8.16.0/2028.8.16.1 to 28.8.31.25428.8.31.2554,094
13128.8.32.0/2028.8.32.1 to 28.8.47.25428.8.47.2554,094
13228.8.48.0/2028.8.48.1 to 28.8.63.25428.8.63.2554,094
13328.8.64.0/2028.8.64.1 to 28.8.79.25428.8.79.2554,094
13428.8.80.0/2028.8.80.1 to 28.8.95.25428.8.95.2554,094
13528.8.96.0/2028.8.96.1 to 28.8.111.25428.8.111.2554,094
13628.8.112.0/2028.8.112.1 to 28.8.127.25428.8.127.2554,094
13728.8.128.0/2028.8.128.1 to 28.8.143.25428.8.143.2554,094
13828.8.144.0/2028.8.144.1 to 28.8.159.25428.8.159.2554,094
13928.8.160.0/2028.8.160.1 to 28.8.175.25428.8.175.2554,094
14028.8.176.0/2028.8.176.1 to 28.8.191.25428.8.191.2554,094
14128.8.192.0/2028.8.192.1 to 28.8.207.25428.8.207.2554,094
14228.8.208.0/2028.8.208.1 to 28.8.223.25428.8.223.2554,094
14328.8.224.0/2028.8.224.1 to 28.8.239.25428.8.239.2554,094
14428.8.240.0/2028.8.240.1 to 28.8.255.25428.8.255.2554,094
14528.9.0.0/2028.9.0.1 to 28.9.15.25428.9.15.2554,094
14628.9.16.0/2028.9.16.1 to 28.9.31.25428.9.31.2554,094
14728.9.32.0/2028.9.32.1 to 28.9.47.25428.9.47.2554,094
14828.9.48.0/2028.9.48.1 to 28.9.63.25428.9.63.2554,094
14928.9.64.0/2028.9.64.1 to 28.9.79.25428.9.79.2554,094
15028.9.80.0/2028.9.80.1 to 28.9.95.25428.9.95.2554,094
15128.9.96.0/2028.9.96.1 to 28.9.111.25428.9.111.2554,094
15228.9.112.0/2028.9.112.1 to 28.9.127.25428.9.127.2554,094
15328.9.128.0/2028.9.128.1 to 28.9.143.25428.9.143.2554,094
15428.9.144.0/2028.9.144.1 to 28.9.159.25428.9.159.2554,094
15528.9.160.0/2028.9.160.1 to 28.9.175.25428.9.175.2554,094
15628.9.176.0/2028.9.176.1 to 28.9.191.25428.9.191.2554,094
15728.9.192.0/2028.9.192.1 to 28.9.207.25428.9.207.2554,094
15828.9.208.0/2028.9.208.1 to 28.9.223.25428.9.223.2554,094
15928.9.224.0/2028.9.224.1 to 28.9.239.25428.9.239.2554,094
16028.9.240.0/2028.9.240.1 to 28.9.255.25428.9.255.2554,094
16128.10.0.0/2028.10.0.1 to 28.10.15.25428.10.15.2554,094
16228.10.16.0/2028.10.16.1 to 28.10.31.25428.10.31.2554,094
16328.10.32.0/2028.10.32.1 to 28.10.47.25428.10.47.2554,094
16428.10.48.0/2028.10.48.1 to 28.10.63.25428.10.63.2554,094
16528.10.64.0/2028.10.64.1 to 28.10.79.25428.10.79.2554,094
16628.10.80.0/2028.10.80.1 to 28.10.95.25428.10.95.2554,094
16728.10.96.0/2028.10.96.1 to 28.10.111.25428.10.111.2554,094
16828.10.112.0/2028.10.112.1 to 28.10.127.25428.10.127.2554,094
16928.10.128.0/2028.10.128.1 to 28.10.143.25428.10.143.2554,094
17028.10.144.0/2028.10.144.1 to 28.10.159.25428.10.159.2554,094
17128.10.160.0/2028.10.160.1 to 28.10.175.25428.10.175.2554,094
17228.10.176.0/2028.10.176.1 to 28.10.191.25428.10.191.2554,094
17328.10.192.0/2028.10.192.1 to 28.10.207.25428.10.207.2554,094
17428.10.208.0/2028.10.208.1 to 28.10.223.25428.10.223.2554,094
17528.10.224.0/2028.10.224.1 to 28.10.239.25428.10.239.2554,094
17628.10.240.0/2028.10.240.1 to 28.10.255.25428.10.255.2554,094
17728.11.0.0/2028.11.0.1 to 28.11.15.25428.11.15.2554,094
17828.11.16.0/2028.11.16.1 to 28.11.31.25428.11.31.2554,094
17928.11.32.0/2028.11.32.1 to 28.11.47.25428.11.47.2554,094
18028.11.48.0/2028.11.48.1 to 28.11.63.25428.11.63.2554,094
18128.11.64.0/2028.11.64.1 to 28.11.79.25428.11.79.2554,094
18228.11.80.0/2028.11.80.1 to 28.11.95.25428.11.95.2554,094
18328.11.96.0/2028.11.96.1 to 28.11.111.25428.11.111.2554,094
18428.11.112.0/2028.11.112.1 to 28.11.127.25428.11.127.2554,094
18528.11.128.0/2028.11.128.1 to 28.11.143.25428.11.143.2554,094
18628.11.144.0/2028.11.144.1 to 28.11.159.25428.11.159.2554,094
18728.11.160.0/2028.11.160.1 to 28.11.175.25428.11.175.2554,094
18828.11.176.0/2028.11.176.1 to 28.11.191.25428.11.191.2554,094
18928.11.192.0/2028.11.192.1 to 28.11.207.25428.11.207.2554,094
19028.11.208.0/2028.11.208.1 to 28.11.223.25428.11.223.2554,094
19128.11.224.0/2028.11.224.1 to 28.11.239.25428.11.239.2554,094
19228.11.240.0/2028.11.240.1 to 28.11.255.25428.11.255.2554,094
19328.12.0.0/2028.12.0.1 to 28.12.15.25428.12.15.2554,094
19428.12.16.0/2028.12.16.1 to 28.12.31.25428.12.31.2554,094
19528.12.32.0/2028.12.32.1 to 28.12.47.25428.12.47.2554,094
19628.12.48.0/2028.12.48.1 to 28.12.63.25428.12.63.2554,094
19728.12.64.0/2028.12.64.1 to 28.12.79.25428.12.79.2554,094
19828.12.80.0/2028.12.80.1 to 28.12.95.25428.12.95.2554,094
19928.12.96.0/2028.12.96.1 to 28.12.111.25428.12.111.2554,094
20028.12.112.0/2028.12.112.1 to 28.12.127.25428.12.127.2554,094
20128.12.128.0/2028.12.128.1 to 28.12.143.25428.12.143.2554,094
20228.12.144.0/2028.12.144.1 to 28.12.159.25428.12.159.2554,094
20328.12.160.0/2028.12.160.1 to 28.12.175.25428.12.175.2554,094
20428.12.176.0/2028.12.176.1 to 28.12.191.25428.12.191.2554,094
20528.12.192.0/2028.12.192.1 to 28.12.207.25428.12.207.2554,094
20628.12.208.0/2028.12.208.1 to 28.12.223.25428.12.223.2554,094
20728.12.224.0/2028.12.224.1 to 28.12.239.25428.12.239.2554,094
20828.12.240.0/2028.12.240.1 to 28.12.255.25428.12.255.2554,094
20928.13.0.0/2028.13.0.1 to 28.13.15.25428.13.15.2554,094
21028.13.16.0/2028.13.16.1 to 28.13.31.25428.13.31.2554,094
21128.13.32.0/2028.13.32.1 to 28.13.47.25428.13.47.2554,094
21228.13.48.0/2028.13.48.1 to 28.13.63.25428.13.63.2554,094
21328.13.64.0/2028.13.64.1 to 28.13.79.25428.13.79.2554,094
21428.13.80.0/2028.13.80.1 to 28.13.95.25428.13.95.2554,094
21528.13.96.0/2028.13.96.1 to 28.13.111.25428.13.111.2554,094
21628.13.112.0/2028.13.112.1 to 28.13.127.25428.13.127.2554,094
21728.13.128.0/2028.13.128.1 to 28.13.143.25428.13.143.2554,094
21828.13.144.0/2028.13.144.1 to 28.13.159.25428.13.159.2554,094
21928.13.160.0/2028.13.160.1 to 28.13.175.25428.13.175.2554,094
22028.13.176.0/2028.13.176.1 to 28.13.191.25428.13.191.2554,094
22128.13.192.0/2028.13.192.1 to 28.13.207.25428.13.207.2554,094
22228.13.208.0/2028.13.208.1 to 28.13.223.25428.13.223.2554,094
22328.13.224.0/2028.13.224.1 to 28.13.239.25428.13.239.2554,094
22428.13.240.0/2028.13.240.1 to 28.13.255.25428.13.255.2554,094
22528.14.0.0/2028.14.0.1 to 28.14.15.25428.14.15.2554,094
22628.14.16.0/2028.14.16.1 to 28.14.31.25428.14.31.2554,094
22728.14.32.0/2028.14.32.1 to 28.14.47.25428.14.47.2554,094
22828.14.48.0/2028.14.48.1 to 28.14.63.25428.14.63.2554,094
22928.14.64.0/2028.14.64.1 to 28.14.79.25428.14.79.2554,094
23028.14.80.0/2028.14.80.1 to 28.14.95.25428.14.95.2554,094
23128.14.96.0/2028.14.96.1 to 28.14.111.25428.14.111.2554,094
23228.14.112.0/2028.14.112.1 to 28.14.127.25428.14.127.2554,094
23328.14.128.0/2028.14.128.1 to 28.14.143.25428.14.143.2554,094
23428.14.144.0/2028.14.144.1 to 28.14.159.25428.14.159.2554,094
23528.14.160.0/2028.14.160.1 to 28.14.175.25428.14.175.2554,094
23628.14.176.0/2028.14.176.1 to 28.14.191.25428.14.191.2554,094
23728.14.192.0/2028.14.192.1 to 28.14.207.25428.14.207.2554,094
23828.14.208.0/2028.14.208.1 to 28.14.223.25428.14.223.2554,094
23928.14.224.0/2028.14.224.1 to 28.14.239.25428.14.239.2554,094
24028.14.240.0/2028.14.240.1 to 28.14.255.25428.14.255.2554,094
24128.15.0.0/2028.15.0.1 to 28.15.15.25428.15.15.2554,094
24228.15.16.0/2028.15.16.1 to 28.15.31.25428.15.31.2554,094
24328.15.32.0/2028.15.32.1 to 28.15.47.25428.15.47.2554,094
24428.15.48.0/2028.15.48.1 to 28.15.63.25428.15.63.2554,094
24528.15.64.0/2028.15.64.1 to 28.15.79.25428.15.79.2554,094
24628.15.80.0/2028.15.80.1 to 28.15.95.25428.15.95.2554,094
24728.15.96.0/2028.15.96.1 to 28.15.111.25428.15.111.2554,094
24828.15.112.0/2028.15.112.1 to 28.15.127.25428.15.127.2554,094
24928.15.128.0/2028.15.128.1 to 28.15.143.25428.15.143.2554,094
25028.15.144.0/2028.15.144.1 to 28.15.159.25428.15.159.2554,094
25128.15.160.0/2028.15.160.1 to 28.15.175.25428.15.175.2554,094
25228.15.176.0/2028.15.176.1 to 28.15.191.25428.15.191.2554,094
25328.15.192.0/2028.15.192.1 to 28.15.207.25428.15.207.2554,094
25428.15.208.0/2028.15.208.1 to 28.15.223.25428.15.223.2554,094
25528.15.224.0/2028.15.224.1 to 28.15.239.25428.15.239.2554,094
25628.15.240.0/2028.15.240.1 to 28.15.255.25428.15.255.2554,094

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.