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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.

Network31.192.0.0/11
Usable hosts2,097,150
Subnet mask255.224.0.0
Addresses2,097,152
Network address
31.192.0.0
Broadcast address
31.223.255.255
First usable
31.192.0.1
Last usable
31.223.255.254
Usable hosts
2,097,150 (2,097,152 less the network and broadcast addresses)
Subnet mask
255.224.0.0
Wildcard mask
0.31.255.255 (Cisco ACLs, OSPF)
Prefix length
/11
Type
Public public
Old class
A (default /8)
As numbers
Hex 1FC00000 · Integer 532676608 to 534773759
Reverse DNS zones
192.31.in-addr.arpa
193.31.in-addr.arpa
194.31.in-addr.arpa
195.31.in-addr.arpa
196.31.in-addr.arpa
197.31.in-addr.arpa
198.31.in-addr.arpa
199.31.in-addr.arpa
200.31.in-addr.arpa
201.31.in-addr.arpa
202.31.in-addr.arpa
203.31.in-addr.arpa
204.31.in-addr.arpa
205.31.in-addr.arpa
206.31.in-addr.arpa
207.31.in-addr.arpa
and 16 more
/11 is not on a 8-bit boundary, so it takes 32 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00011111.11000000.00000000.0000000031.192.0.0
Subnet mask11111111.11100000.00000000.00000000255.224.0.0
Network00011111.11000000.00000000.0000000031.192.0.0
Broadcast00011111.11011111.11111111.1111111131.223.255.255
Split into smaller subnets/19
/12 (2)/13 (4)/14 (8)/15 (16)/16 (32)/17 (64)/18 (128)/19 (256)/20 (512)/21 (1,024)/22 (2,048)/23 (4,096)

31.192.0.0/11 makes 256 subnets of /19.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
131.192.0.0/1931.192.0.1 to 31.192.31.25431.192.31.2558,190
231.192.32.0/1931.192.32.1 to 31.192.63.25431.192.63.2558,190
331.192.64.0/1931.192.64.1 to 31.192.95.25431.192.95.2558,190
431.192.96.0/1931.192.96.1 to 31.192.127.25431.192.127.2558,190
531.192.128.0/1931.192.128.1 to 31.192.159.25431.192.159.2558,190
631.192.160.0/1931.192.160.1 to 31.192.191.25431.192.191.2558,190
731.192.192.0/1931.192.192.1 to 31.192.223.25431.192.223.2558,190
831.192.224.0/1931.192.224.1 to 31.192.255.25431.192.255.2558,190
931.193.0.0/1931.193.0.1 to 31.193.31.25431.193.31.2558,190
1031.193.32.0/1931.193.32.1 to 31.193.63.25431.193.63.2558,190
1131.193.64.0/1931.193.64.1 to 31.193.95.25431.193.95.2558,190
1231.193.96.0/1931.193.96.1 to 31.193.127.25431.193.127.2558,190
1331.193.128.0/1931.193.128.1 to 31.193.159.25431.193.159.2558,190
1431.193.160.0/1931.193.160.1 to 31.193.191.25431.193.191.2558,190
1531.193.192.0/1931.193.192.1 to 31.193.223.25431.193.223.2558,190
1631.193.224.0/1931.193.224.1 to 31.193.255.25431.193.255.2558,190
1731.194.0.0/1931.194.0.1 to 31.194.31.25431.194.31.2558,190
1831.194.32.0/1931.194.32.1 to 31.194.63.25431.194.63.2558,190
1931.194.64.0/1931.194.64.1 to 31.194.95.25431.194.95.2558,190
2031.194.96.0/1931.194.96.1 to 31.194.127.25431.194.127.2558,190
2131.194.128.0/1931.194.128.1 to 31.194.159.25431.194.159.2558,190
2231.194.160.0/1931.194.160.1 to 31.194.191.25431.194.191.2558,190
2331.194.192.0/1931.194.192.1 to 31.194.223.25431.194.223.2558,190
2431.194.224.0/1931.194.224.1 to 31.194.255.25431.194.255.2558,190
2531.195.0.0/1931.195.0.1 to 31.195.31.25431.195.31.2558,190
2631.195.32.0/1931.195.32.1 to 31.195.63.25431.195.63.2558,190
2731.195.64.0/1931.195.64.1 to 31.195.95.25431.195.95.2558,190
2831.195.96.0/1931.195.96.1 to 31.195.127.25431.195.127.2558,190
2931.195.128.0/1931.195.128.1 to 31.195.159.25431.195.159.2558,190
3031.195.160.0/1931.195.160.1 to 31.195.191.25431.195.191.2558,190
3131.195.192.0/1931.195.192.1 to 31.195.223.25431.195.223.2558,190
3231.195.224.0/1931.195.224.1 to 31.195.255.25431.195.255.2558,190
3331.196.0.0/1931.196.0.1 to 31.196.31.25431.196.31.2558,190
3431.196.32.0/1931.196.32.1 to 31.196.63.25431.196.63.2558,190
3531.196.64.0/1931.196.64.1 to 31.196.95.25431.196.95.2558,190
3631.196.96.0/1931.196.96.1 to 31.196.127.25431.196.127.2558,190
3731.196.128.0/1931.196.128.1 to 31.196.159.25431.196.159.2558,190
3831.196.160.0/1931.196.160.1 to 31.196.191.25431.196.191.2558,190
3931.196.192.0/1931.196.192.1 to 31.196.223.25431.196.223.2558,190
4031.196.224.0/1931.196.224.1 to 31.196.255.25431.196.255.2558,190
4131.197.0.0/1931.197.0.1 to 31.197.31.25431.197.31.2558,190
4231.197.32.0/1931.197.32.1 to 31.197.63.25431.197.63.2558,190
4331.197.64.0/1931.197.64.1 to 31.197.95.25431.197.95.2558,190
4431.197.96.0/1931.197.96.1 to 31.197.127.25431.197.127.2558,190
4531.197.128.0/1931.197.128.1 to 31.197.159.25431.197.159.2558,190
4631.197.160.0/1931.197.160.1 to 31.197.191.25431.197.191.2558,190
4731.197.192.0/1931.197.192.1 to 31.197.223.25431.197.223.2558,190
4831.197.224.0/1931.197.224.1 to 31.197.255.25431.197.255.2558,190
4931.198.0.0/1931.198.0.1 to 31.198.31.25431.198.31.2558,190
5031.198.32.0/1931.198.32.1 to 31.198.63.25431.198.63.2558,190
5131.198.64.0/1931.198.64.1 to 31.198.95.25431.198.95.2558,190
5231.198.96.0/1931.198.96.1 to 31.198.127.25431.198.127.2558,190
5331.198.128.0/1931.198.128.1 to 31.198.159.25431.198.159.2558,190
5431.198.160.0/1931.198.160.1 to 31.198.191.25431.198.191.2558,190
5531.198.192.0/1931.198.192.1 to 31.198.223.25431.198.223.2558,190
5631.198.224.0/1931.198.224.1 to 31.198.255.25431.198.255.2558,190
5731.199.0.0/1931.199.0.1 to 31.199.31.25431.199.31.2558,190
5831.199.32.0/1931.199.32.1 to 31.199.63.25431.199.63.2558,190
5931.199.64.0/1931.199.64.1 to 31.199.95.25431.199.95.2558,190
6031.199.96.0/1931.199.96.1 to 31.199.127.25431.199.127.2558,190
6131.199.128.0/1931.199.128.1 to 31.199.159.25431.199.159.2558,190
6231.199.160.0/1931.199.160.1 to 31.199.191.25431.199.191.2558,190
6331.199.192.0/1931.199.192.1 to 31.199.223.25431.199.223.2558,190
6431.199.224.0/1931.199.224.1 to 31.199.255.25431.199.255.2558,190
6531.200.0.0/1931.200.0.1 to 31.200.31.25431.200.31.2558,190
6631.200.32.0/1931.200.32.1 to 31.200.63.25431.200.63.2558,190
6731.200.64.0/1931.200.64.1 to 31.200.95.25431.200.95.2558,190
6831.200.96.0/1931.200.96.1 to 31.200.127.25431.200.127.2558,190
6931.200.128.0/1931.200.128.1 to 31.200.159.25431.200.159.2558,190
7031.200.160.0/1931.200.160.1 to 31.200.191.25431.200.191.2558,190
7131.200.192.0/1931.200.192.1 to 31.200.223.25431.200.223.2558,190
7231.200.224.0/1931.200.224.1 to 31.200.255.25431.200.255.2558,190
7331.201.0.0/1931.201.0.1 to 31.201.31.25431.201.31.2558,190
7431.201.32.0/1931.201.32.1 to 31.201.63.25431.201.63.2558,190
7531.201.64.0/1931.201.64.1 to 31.201.95.25431.201.95.2558,190
7631.201.96.0/1931.201.96.1 to 31.201.127.25431.201.127.2558,190
7731.201.128.0/1931.201.128.1 to 31.201.159.25431.201.159.2558,190
7831.201.160.0/1931.201.160.1 to 31.201.191.25431.201.191.2558,190
7931.201.192.0/1931.201.192.1 to 31.201.223.25431.201.223.2558,190
8031.201.224.0/1931.201.224.1 to 31.201.255.25431.201.255.2558,190
8131.202.0.0/1931.202.0.1 to 31.202.31.25431.202.31.2558,190
8231.202.32.0/1931.202.32.1 to 31.202.63.25431.202.63.2558,190
8331.202.64.0/1931.202.64.1 to 31.202.95.25431.202.95.2558,190
8431.202.96.0/1931.202.96.1 to 31.202.127.25431.202.127.2558,190
8531.202.128.0/1931.202.128.1 to 31.202.159.25431.202.159.2558,190
8631.202.160.0/1931.202.160.1 to 31.202.191.25431.202.191.2558,190
8731.202.192.0/1931.202.192.1 to 31.202.223.25431.202.223.2558,190
8831.202.224.0/1931.202.224.1 to 31.202.255.25431.202.255.2558,190
8931.203.0.0/1931.203.0.1 to 31.203.31.25431.203.31.2558,190
9031.203.32.0/1931.203.32.1 to 31.203.63.25431.203.63.2558,190
9131.203.64.0/1931.203.64.1 to 31.203.95.25431.203.95.2558,190
9231.203.96.0/1931.203.96.1 to 31.203.127.25431.203.127.2558,190
9331.203.128.0/1931.203.128.1 to 31.203.159.25431.203.159.2558,190
9431.203.160.0/1931.203.160.1 to 31.203.191.25431.203.191.2558,190
9531.203.192.0/1931.203.192.1 to 31.203.223.25431.203.223.2558,190
9631.203.224.0/1931.203.224.1 to 31.203.255.25431.203.255.2558,190
9731.204.0.0/1931.204.0.1 to 31.204.31.25431.204.31.2558,190
9831.204.32.0/1931.204.32.1 to 31.204.63.25431.204.63.2558,190
9931.204.64.0/1931.204.64.1 to 31.204.95.25431.204.95.2558,190
10031.204.96.0/1931.204.96.1 to 31.204.127.25431.204.127.2558,190
10131.204.128.0/1931.204.128.1 to 31.204.159.25431.204.159.2558,190
10231.204.160.0/1931.204.160.1 to 31.204.191.25431.204.191.2558,190
10331.204.192.0/1931.204.192.1 to 31.204.223.25431.204.223.2558,190
10431.204.224.0/1931.204.224.1 to 31.204.255.25431.204.255.2558,190
10531.205.0.0/1931.205.0.1 to 31.205.31.25431.205.31.2558,190
10631.205.32.0/1931.205.32.1 to 31.205.63.25431.205.63.2558,190
10731.205.64.0/1931.205.64.1 to 31.205.95.25431.205.95.2558,190
10831.205.96.0/1931.205.96.1 to 31.205.127.25431.205.127.2558,190
10931.205.128.0/1931.205.128.1 to 31.205.159.25431.205.159.2558,190
11031.205.160.0/1931.205.160.1 to 31.205.191.25431.205.191.2558,190
11131.205.192.0/1931.205.192.1 to 31.205.223.25431.205.223.2558,190
11231.205.224.0/1931.205.224.1 to 31.205.255.25431.205.255.2558,190
11331.206.0.0/1931.206.0.1 to 31.206.31.25431.206.31.2558,190
11431.206.32.0/1931.206.32.1 to 31.206.63.25431.206.63.2558,190
11531.206.64.0/1931.206.64.1 to 31.206.95.25431.206.95.2558,190
11631.206.96.0/1931.206.96.1 to 31.206.127.25431.206.127.2558,190
11731.206.128.0/1931.206.128.1 to 31.206.159.25431.206.159.2558,190
11831.206.160.0/1931.206.160.1 to 31.206.191.25431.206.191.2558,190
11931.206.192.0/1931.206.192.1 to 31.206.223.25431.206.223.2558,190
12031.206.224.0/1931.206.224.1 to 31.206.255.25431.206.255.2558,190
12131.207.0.0/1931.207.0.1 to 31.207.31.25431.207.31.2558,190
12231.207.32.0/1931.207.32.1 to 31.207.63.25431.207.63.2558,190
12331.207.64.0/1931.207.64.1 to 31.207.95.25431.207.95.2558,190
12431.207.96.0/1931.207.96.1 to 31.207.127.25431.207.127.2558,190
12531.207.128.0/1931.207.128.1 to 31.207.159.25431.207.159.2558,190
12631.207.160.0/1931.207.160.1 to 31.207.191.25431.207.191.2558,190
12731.207.192.0/1931.207.192.1 to 31.207.223.25431.207.223.2558,190
12831.207.224.0/1931.207.224.1 to 31.207.255.25431.207.255.2558,190
12931.208.0.0/1931.208.0.1 to 31.208.31.25431.208.31.2558,190
13031.208.32.0/1931.208.32.1 to 31.208.63.25431.208.63.2558,190
13131.208.64.0/1931.208.64.1 to 31.208.95.25431.208.95.2558,190
13231.208.96.0/1931.208.96.1 to 31.208.127.25431.208.127.2558,190
13331.208.128.0/1931.208.128.1 to 31.208.159.25431.208.159.2558,190
13431.208.160.0/1931.208.160.1 to 31.208.191.25431.208.191.2558,190
13531.208.192.0/1931.208.192.1 to 31.208.223.25431.208.223.2558,190
13631.208.224.0/1931.208.224.1 to 31.208.255.25431.208.255.2558,190
13731.209.0.0/1931.209.0.1 to 31.209.31.25431.209.31.2558,190
13831.209.32.0/1931.209.32.1 to 31.209.63.25431.209.63.2558,190
13931.209.64.0/1931.209.64.1 to 31.209.95.25431.209.95.2558,190
14031.209.96.0/1931.209.96.1 to 31.209.127.25431.209.127.2558,190
14131.209.128.0/1931.209.128.1 to 31.209.159.25431.209.159.2558,190
14231.209.160.0/1931.209.160.1 to 31.209.191.25431.209.191.2558,190
14331.209.192.0/1931.209.192.1 to 31.209.223.25431.209.223.2558,190
14431.209.224.0/1931.209.224.1 to 31.209.255.25431.209.255.2558,190
14531.210.0.0/1931.210.0.1 to 31.210.31.25431.210.31.2558,190
14631.210.32.0/1931.210.32.1 to 31.210.63.25431.210.63.2558,190
14731.210.64.0/1931.210.64.1 to 31.210.95.25431.210.95.2558,190
14831.210.96.0/1931.210.96.1 to 31.210.127.25431.210.127.2558,190
14931.210.128.0/1931.210.128.1 to 31.210.159.25431.210.159.2558,190
15031.210.160.0/1931.210.160.1 to 31.210.191.25431.210.191.2558,190
15131.210.192.0/1931.210.192.1 to 31.210.223.25431.210.223.2558,190
15231.210.224.0/1931.210.224.1 to 31.210.255.25431.210.255.2558,190
15331.211.0.0/1931.211.0.1 to 31.211.31.25431.211.31.2558,190
15431.211.32.0/1931.211.32.1 to 31.211.63.25431.211.63.2558,190
15531.211.64.0/1931.211.64.1 to 31.211.95.25431.211.95.2558,190
15631.211.96.0/1931.211.96.1 to 31.211.127.25431.211.127.2558,190
15731.211.128.0/1931.211.128.1 to 31.211.159.25431.211.159.2558,190
15831.211.160.0/1931.211.160.1 to 31.211.191.25431.211.191.2558,190
15931.211.192.0/1931.211.192.1 to 31.211.223.25431.211.223.2558,190
16031.211.224.0/1931.211.224.1 to 31.211.255.25431.211.255.2558,190
16131.212.0.0/1931.212.0.1 to 31.212.31.25431.212.31.2558,190
16231.212.32.0/1931.212.32.1 to 31.212.63.25431.212.63.2558,190
16331.212.64.0/1931.212.64.1 to 31.212.95.25431.212.95.2558,190
16431.212.96.0/1931.212.96.1 to 31.212.127.25431.212.127.2558,190
16531.212.128.0/1931.212.128.1 to 31.212.159.25431.212.159.2558,190
16631.212.160.0/1931.212.160.1 to 31.212.191.25431.212.191.2558,190
16731.212.192.0/1931.212.192.1 to 31.212.223.25431.212.223.2558,190
16831.212.224.0/1931.212.224.1 to 31.212.255.25431.212.255.2558,190
16931.213.0.0/1931.213.0.1 to 31.213.31.25431.213.31.2558,190
17031.213.32.0/1931.213.32.1 to 31.213.63.25431.213.63.2558,190
17131.213.64.0/1931.213.64.1 to 31.213.95.25431.213.95.2558,190
17231.213.96.0/1931.213.96.1 to 31.213.127.25431.213.127.2558,190
17331.213.128.0/1931.213.128.1 to 31.213.159.25431.213.159.2558,190
17431.213.160.0/1931.213.160.1 to 31.213.191.25431.213.191.2558,190
17531.213.192.0/1931.213.192.1 to 31.213.223.25431.213.223.2558,190
17631.213.224.0/1931.213.224.1 to 31.213.255.25431.213.255.2558,190
17731.214.0.0/1931.214.0.1 to 31.214.31.25431.214.31.2558,190
17831.214.32.0/1931.214.32.1 to 31.214.63.25431.214.63.2558,190
17931.214.64.0/1931.214.64.1 to 31.214.95.25431.214.95.2558,190
18031.214.96.0/1931.214.96.1 to 31.214.127.25431.214.127.2558,190
18131.214.128.0/1931.214.128.1 to 31.214.159.25431.214.159.2558,190
18231.214.160.0/1931.214.160.1 to 31.214.191.25431.214.191.2558,190
18331.214.192.0/1931.214.192.1 to 31.214.223.25431.214.223.2558,190
18431.214.224.0/1931.214.224.1 to 31.214.255.25431.214.255.2558,190
18531.215.0.0/1931.215.0.1 to 31.215.31.25431.215.31.2558,190
18631.215.32.0/1931.215.32.1 to 31.215.63.25431.215.63.2558,190
18731.215.64.0/1931.215.64.1 to 31.215.95.25431.215.95.2558,190
18831.215.96.0/1931.215.96.1 to 31.215.127.25431.215.127.2558,190
18931.215.128.0/1931.215.128.1 to 31.215.159.25431.215.159.2558,190
19031.215.160.0/1931.215.160.1 to 31.215.191.25431.215.191.2558,190
19131.215.192.0/1931.215.192.1 to 31.215.223.25431.215.223.2558,190
19231.215.224.0/1931.215.224.1 to 31.215.255.25431.215.255.2558,190
19331.216.0.0/1931.216.0.1 to 31.216.31.25431.216.31.2558,190
19431.216.32.0/1931.216.32.1 to 31.216.63.25431.216.63.2558,190
19531.216.64.0/1931.216.64.1 to 31.216.95.25431.216.95.2558,190
19631.216.96.0/1931.216.96.1 to 31.216.127.25431.216.127.2558,190
19731.216.128.0/1931.216.128.1 to 31.216.159.25431.216.159.2558,190
19831.216.160.0/1931.216.160.1 to 31.216.191.25431.216.191.2558,190
19931.216.192.0/1931.216.192.1 to 31.216.223.25431.216.223.2558,190
20031.216.224.0/1931.216.224.1 to 31.216.255.25431.216.255.2558,190
20131.217.0.0/1931.217.0.1 to 31.217.31.25431.217.31.2558,190
20231.217.32.0/1931.217.32.1 to 31.217.63.25431.217.63.2558,190
20331.217.64.0/1931.217.64.1 to 31.217.95.25431.217.95.2558,190
20431.217.96.0/1931.217.96.1 to 31.217.127.25431.217.127.2558,190
20531.217.128.0/1931.217.128.1 to 31.217.159.25431.217.159.2558,190
20631.217.160.0/1931.217.160.1 to 31.217.191.25431.217.191.2558,190
20731.217.192.0/1931.217.192.1 to 31.217.223.25431.217.223.2558,190
20831.217.224.0/1931.217.224.1 to 31.217.255.25431.217.255.2558,190
20931.218.0.0/1931.218.0.1 to 31.218.31.25431.218.31.2558,190
21031.218.32.0/1931.218.32.1 to 31.218.63.25431.218.63.2558,190
21131.218.64.0/1931.218.64.1 to 31.218.95.25431.218.95.2558,190
21231.218.96.0/1931.218.96.1 to 31.218.127.25431.218.127.2558,190
21331.218.128.0/1931.218.128.1 to 31.218.159.25431.218.159.2558,190
21431.218.160.0/1931.218.160.1 to 31.218.191.25431.218.191.2558,190
21531.218.192.0/1931.218.192.1 to 31.218.223.25431.218.223.2558,190
21631.218.224.0/1931.218.224.1 to 31.218.255.25431.218.255.2558,190
21731.219.0.0/1931.219.0.1 to 31.219.31.25431.219.31.2558,190
21831.219.32.0/1931.219.32.1 to 31.219.63.25431.219.63.2558,190
21931.219.64.0/1931.219.64.1 to 31.219.95.25431.219.95.2558,190
22031.219.96.0/1931.219.96.1 to 31.219.127.25431.219.127.2558,190
22131.219.128.0/1931.219.128.1 to 31.219.159.25431.219.159.2558,190
22231.219.160.0/1931.219.160.1 to 31.219.191.25431.219.191.2558,190
22331.219.192.0/1931.219.192.1 to 31.219.223.25431.219.223.2558,190
22431.219.224.0/1931.219.224.1 to 31.219.255.25431.219.255.2558,190
22531.220.0.0/1931.220.0.1 to 31.220.31.25431.220.31.2558,190
22631.220.32.0/1931.220.32.1 to 31.220.63.25431.220.63.2558,190
22731.220.64.0/1931.220.64.1 to 31.220.95.25431.220.95.2558,190
22831.220.96.0/1931.220.96.1 to 31.220.127.25431.220.127.2558,190
22931.220.128.0/1931.220.128.1 to 31.220.159.25431.220.159.2558,190
23031.220.160.0/1931.220.160.1 to 31.220.191.25431.220.191.2558,190
23131.220.192.0/1931.220.192.1 to 31.220.223.25431.220.223.2558,190
23231.220.224.0/1931.220.224.1 to 31.220.255.25431.220.255.2558,190
23331.221.0.0/1931.221.0.1 to 31.221.31.25431.221.31.2558,190
23431.221.32.0/1931.221.32.1 to 31.221.63.25431.221.63.2558,190
23531.221.64.0/1931.221.64.1 to 31.221.95.25431.221.95.2558,190
23631.221.96.0/1931.221.96.1 to 31.221.127.25431.221.127.2558,190
23731.221.128.0/1931.221.128.1 to 31.221.159.25431.221.159.2558,190
23831.221.160.0/1931.221.160.1 to 31.221.191.25431.221.191.2558,190
23931.221.192.0/1931.221.192.1 to 31.221.223.25431.221.223.2558,190
24031.221.224.0/1931.221.224.1 to 31.221.255.25431.221.255.2558,190
24131.222.0.0/1931.222.0.1 to 31.222.31.25431.222.31.2558,190
24231.222.32.0/1931.222.32.1 to 31.222.63.25431.222.63.2558,190
24331.222.64.0/1931.222.64.1 to 31.222.95.25431.222.95.2558,190
24431.222.96.0/1931.222.96.1 to 31.222.127.25431.222.127.2558,190
24531.222.128.0/1931.222.128.1 to 31.222.159.25431.222.159.2558,190
24631.222.160.0/1931.222.160.1 to 31.222.191.25431.222.191.2558,190
24731.222.192.0/1931.222.192.1 to 31.222.223.25431.222.223.2558,190
24831.222.224.0/1931.222.224.1 to 31.222.255.25431.222.255.2558,190
24931.223.0.0/1931.223.0.1 to 31.223.31.25431.223.31.2558,190
25031.223.32.0/1931.223.32.1 to 31.223.63.25431.223.63.2558,190
25131.223.64.0/1931.223.64.1 to 31.223.95.25431.223.95.2558,190
25231.223.96.0/1931.223.96.1 to 31.223.127.25431.223.127.2558,190
25331.223.128.0/1931.223.128.1 to 31.223.159.25431.223.159.2558,190
25431.223.160.0/1931.223.160.1 to 31.223.191.25431.223.191.2558,190
25531.223.192.0/1931.223.192.1 to 31.223.223.25431.223.223.2558,190
25631.223.224.0/1931.223.224.1 to 31.223.255.25431.223.255.2558,190

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.