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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.

Network43.0.0.0/10
Usable hosts4,194,302
Subnet mask255.192.0.0
Addresses4,194,304
Network address
43.0.0.0
Broadcast address
43.63.255.255
First usable
43.0.0.1
Last usable
43.63.255.254
Usable hosts
4,194,302 (4,194,304 less the network and broadcast addresses)
Subnet mask
255.192.0.0
Wildcard mask
0.63.255.255 (Cisco ACLs, OSPF)
Prefix length
/10
Type
Public public
Old class
A (default /8)
As numbers
Hex 2B000000 · Integer 721420288 to 725614591
Reverse DNS zones
0.43.in-addr.arpa
1.43.in-addr.arpa
2.43.in-addr.arpa
3.43.in-addr.arpa
4.43.in-addr.arpa
5.43.in-addr.arpa
6.43.in-addr.arpa
7.43.in-addr.arpa
8.43.in-addr.arpa
9.43.in-addr.arpa
10.43.in-addr.arpa
11.43.in-addr.arpa
12.43.in-addr.arpa
13.43.in-addr.arpa
14.43.in-addr.arpa
15.43.in-addr.arpa
and 48 more
/10 is not on a 8-bit boundary, so it takes 64 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00101011.00000000.00000000.0000000043.0.0.0
Subnet mask11111111.11000000.00000000.00000000255.192.0.0
Network00101011.00000000.00000000.0000000043.0.0.0
Broadcast00101011.00111111.11111111.1111111143.63.255.255
Split into smaller subnets/19
/11 (2)/12 (4)/13 (8)/14 (16)/15 (32)/16 (64)/17 (128)/18 (256)/19 (512)/20 (1,024)/21 (2,048)/22 (4,096)

43.0.0.0/10 makes 512 subnets of /19; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
143.0.0.0/1943.0.0.1 to 43.0.31.25443.0.31.2558,190
243.0.32.0/1943.0.32.1 to 43.0.63.25443.0.63.2558,190
343.0.64.0/1943.0.64.1 to 43.0.95.25443.0.95.2558,190
443.0.96.0/1943.0.96.1 to 43.0.127.25443.0.127.2558,190
543.0.128.0/1943.0.128.1 to 43.0.159.25443.0.159.2558,190
643.0.160.0/1943.0.160.1 to 43.0.191.25443.0.191.2558,190
743.0.192.0/1943.0.192.1 to 43.0.223.25443.0.223.2558,190
843.0.224.0/1943.0.224.1 to 43.0.255.25443.0.255.2558,190
943.1.0.0/1943.1.0.1 to 43.1.31.25443.1.31.2558,190
1043.1.32.0/1943.1.32.1 to 43.1.63.25443.1.63.2558,190
1143.1.64.0/1943.1.64.1 to 43.1.95.25443.1.95.2558,190
1243.1.96.0/1943.1.96.1 to 43.1.127.25443.1.127.2558,190
1343.1.128.0/1943.1.128.1 to 43.1.159.25443.1.159.2558,190
1443.1.160.0/1943.1.160.1 to 43.1.191.25443.1.191.2558,190
1543.1.192.0/1943.1.192.1 to 43.1.223.25443.1.223.2558,190
1643.1.224.0/1943.1.224.1 to 43.1.255.25443.1.255.2558,190
1743.2.0.0/1943.2.0.1 to 43.2.31.25443.2.31.2558,190
1843.2.32.0/1943.2.32.1 to 43.2.63.25443.2.63.2558,190
1943.2.64.0/1943.2.64.1 to 43.2.95.25443.2.95.2558,190
2043.2.96.0/1943.2.96.1 to 43.2.127.25443.2.127.2558,190
2143.2.128.0/1943.2.128.1 to 43.2.159.25443.2.159.2558,190
2243.2.160.0/1943.2.160.1 to 43.2.191.25443.2.191.2558,190
2343.2.192.0/1943.2.192.1 to 43.2.223.25443.2.223.2558,190
2443.2.224.0/1943.2.224.1 to 43.2.255.25443.2.255.2558,190
2543.3.0.0/1943.3.0.1 to 43.3.31.25443.3.31.2558,190
2643.3.32.0/1943.3.32.1 to 43.3.63.25443.3.63.2558,190
2743.3.64.0/1943.3.64.1 to 43.3.95.25443.3.95.2558,190
2843.3.96.0/1943.3.96.1 to 43.3.127.25443.3.127.2558,190
2943.3.128.0/1943.3.128.1 to 43.3.159.25443.3.159.2558,190
3043.3.160.0/1943.3.160.1 to 43.3.191.25443.3.191.2558,190
3143.3.192.0/1943.3.192.1 to 43.3.223.25443.3.223.2558,190
3243.3.224.0/1943.3.224.1 to 43.3.255.25443.3.255.2558,190
3343.4.0.0/1943.4.0.1 to 43.4.31.25443.4.31.2558,190
3443.4.32.0/1943.4.32.1 to 43.4.63.25443.4.63.2558,190
3543.4.64.0/1943.4.64.1 to 43.4.95.25443.4.95.2558,190
3643.4.96.0/1943.4.96.1 to 43.4.127.25443.4.127.2558,190
3743.4.128.0/1943.4.128.1 to 43.4.159.25443.4.159.2558,190
3843.4.160.0/1943.4.160.1 to 43.4.191.25443.4.191.2558,190
3943.4.192.0/1943.4.192.1 to 43.4.223.25443.4.223.2558,190
4043.4.224.0/1943.4.224.1 to 43.4.255.25443.4.255.2558,190
4143.5.0.0/1943.5.0.1 to 43.5.31.25443.5.31.2558,190
4243.5.32.0/1943.5.32.1 to 43.5.63.25443.5.63.2558,190
4343.5.64.0/1943.5.64.1 to 43.5.95.25443.5.95.2558,190
4443.5.96.0/1943.5.96.1 to 43.5.127.25443.5.127.2558,190
4543.5.128.0/1943.5.128.1 to 43.5.159.25443.5.159.2558,190
4643.5.160.0/1943.5.160.1 to 43.5.191.25443.5.191.2558,190
4743.5.192.0/1943.5.192.1 to 43.5.223.25443.5.223.2558,190
4843.5.224.0/1943.5.224.1 to 43.5.255.25443.5.255.2558,190
4943.6.0.0/1943.6.0.1 to 43.6.31.25443.6.31.2558,190
5043.6.32.0/1943.6.32.1 to 43.6.63.25443.6.63.2558,190
5143.6.64.0/1943.6.64.1 to 43.6.95.25443.6.95.2558,190
5243.6.96.0/1943.6.96.1 to 43.6.127.25443.6.127.2558,190
5343.6.128.0/1943.6.128.1 to 43.6.159.25443.6.159.2558,190
5443.6.160.0/1943.6.160.1 to 43.6.191.25443.6.191.2558,190
5543.6.192.0/1943.6.192.1 to 43.6.223.25443.6.223.2558,190
5643.6.224.0/1943.6.224.1 to 43.6.255.25443.6.255.2558,190
5743.7.0.0/1943.7.0.1 to 43.7.31.25443.7.31.2558,190
5843.7.32.0/1943.7.32.1 to 43.7.63.25443.7.63.2558,190
5943.7.64.0/1943.7.64.1 to 43.7.95.25443.7.95.2558,190
6043.7.96.0/1943.7.96.1 to 43.7.127.25443.7.127.2558,190
6143.7.128.0/1943.7.128.1 to 43.7.159.25443.7.159.2558,190
6243.7.160.0/1943.7.160.1 to 43.7.191.25443.7.191.2558,190
6343.7.192.0/1943.7.192.1 to 43.7.223.25443.7.223.2558,190
6443.7.224.0/1943.7.224.1 to 43.7.255.25443.7.255.2558,190
6543.8.0.0/1943.8.0.1 to 43.8.31.25443.8.31.2558,190
6643.8.32.0/1943.8.32.1 to 43.8.63.25443.8.63.2558,190
6743.8.64.0/1943.8.64.1 to 43.8.95.25443.8.95.2558,190
6843.8.96.0/1943.8.96.1 to 43.8.127.25443.8.127.2558,190
6943.8.128.0/1943.8.128.1 to 43.8.159.25443.8.159.2558,190
7043.8.160.0/1943.8.160.1 to 43.8.191.25443.8.191.2558,190
7143.8.192.0/1943.8.192.1 to 43.8.223.25443.8.223.2558,190
7243.8.224.0/1943.8.224.1 to 43.8.255.25443.8.255.2558,190
7343.9.0.0/1943.9.0.1 to 43.9.31.25443.9.31.2558,190
7443.9.32.0/1943.9.32.1 to 43.9.63.25443.9.63.2558,190
7543.9.64.0/1943.9.64.1 to 43.9.95.25443.9.95.2558,190
7643.9.96.0/1943.9.96.1 to 43.9.127.25443.9.127.2558,190
7743.9.128.0/1943.9.128.1 to 43.9.159.25443.9.159.2558,190
7843.9.160.0/1943.9.160.1 to 43.9.191.25443.9.191.2558,190
7943.9.192.0/1943.9.192.1 to 43.9.223.25443.9.223.2558,190
8043.9.224.0/1943.9.224.1 to 43.9.255.25443.9.255.2558,190
8143.10.0.0/1943.10.0.1 to 43.10.31.25443.10.31.2558,190
8243.10.32.0/1943.10.32.1 to 43.10.63.25443.10.63.2558,190
8343.10.64.0/1943.10.64.1 to 43.10.95.25443.10.95.2558,190
8443.10.96.0/1943.10.96.1 to 43.10.127.25443.10.127.2558,190
8543.10.128.0/1943.10.128.1 to 43.10.159.25443.10.159.2558,190
8643.10.160.0/1943.10.160.1 to 43.10.191.25443.10.191.2558,190
8743.10.192.0/1943.10.192.1 to 43.10.223.25443.10.223.2558,190
8843.10.224.0/1943.10.224.1 to 43.10.255.25443.10.255.2558,190
8943.11.0.0/1943.11.0.1 to 43.11.31.25443.11.31.2558,190
9043.11.32.0/1943.11.32.1 to 43.11.63.25443.11.63.2558,190
9143.11.64.0/1943.11.64.1 to 43.11.95.25443.11.95.2558,190
9243.11.96.0/1943.11.96.1 to 43.11.127.25443.11.127.2558,190
9343.11.128.0/1943.11.128.1 to 43.11.159.25443.11.159.2558,190
9443.11.160.0/1943.11.160.1 to 43.11.191.25443.11.191.2558,190
9543.11.192.0/1943.11.192.1 to 43.11.223.25443.11.223.2558,190
9643.11.224.0/1943.11.224.1 to 43.11.255.25443.11.255.2558,190
9743.12.0.0/1943.12.0.1 to 43.12.31.25443.12.31.2558,190
9843.12.32.0/1943.12.32.1 to 43.12.63.25443.12.63.2558,190
9943.12.64.0/1943.12.64.1 to 43.12.95.25443.12.95.2558,190
10043.12.96.0/1943.12.96.1 to 43.12.127.25443.12.127.2558,190
10143.12.128.0/1943.12.128.1 to 43.12.159.25443.12.159.2558,190
10243.12.160.0/1943.12.160.1 to 43.12.191.25443.12.191.2558,190
10343.12.192.0/1943.12.192.1 to 43.12.223.25443.12.223.2558,190
10443.12.224.0/1943.12.224.1 to 43.12.255.25443.12.255.2558,190
10543.13.0.0/1943.13.0.1 to 43.13.31.25443.13.31.2558,190
10643.13.32.0/1943.13.32.1 to 43.13.63.25443.13.63.2558,190
10743.13.64.0/1943.13.64.1 to 43.13.95.25443.13.95.2558,190
10843.13.96.0/1943.13.96.1 to 43.13.127.25443.13.127.2558,190
10943.13.128.0/1943.13.128.1 to 43.13.159.25443.13.159.2558,190
11043.13.160.0/1943.13.160.1 to 43.13.191.25443.13.191.2558,190
11143.13.192.0/1943.13.192.1 to 43.13.223.25443.13.223.2558,190
11243.13.224.0/1943.13.224.1 to 43.13.255.25443.13.255.2558,190
11343.14.0.0/1943.14.0.1 to 43.14.31.25443.14.31.2558,190
11443.14.32.0/1943.14.32.1 to 43.14.63.25443.14.63.2558,190
11543.14.64.0/1943.14.64.1 to 43.14.95.25443.14.95.2558,190
11643.14.96.0/1943.14.96.1 to 43.14.127.25443.14.127.2558,190
11743.14.128.0/1943.14.128.1 to 43.14.159.25443.14.159.2558,190
11843.14.160.0/1943.14.160.1 to 43.14.191.25443.14.191.2558,190
11943.14.192.0/1943.14.192.1 to 43.14.223.25443.14.223.2558,190
12043.14.224.0/1943.14.224.1 to 43.14.255.25443.14.255.2558,190
12143.15.0.0/1943.15.0.1 to 43.15.31.25443.15.31.2558,190
12243.15.32.0/1943.15.32.1 to 43.15.63.25443.15.63.2558,190
12343.15.64.0/1943.15.64.1 to 43.15.95.25443.15.95.2558,190
12443.15.96.0/1943.15.96.1 to 43.15.127.25443.15.127.2558,190
12543.15.128.0/1943.15.128.1 to 43.15.159.25443.15.159.2558,190
12643.15.160.0/1943.15.160.1 to 43.15.191.25443.15.191.2558,190
12743.15.192.0/1943.15.192.1 to 43.15.223.25443.15.223.2558,190
12843.15.224.0/1943.15.224.1 to 43.15.255.25443.15.255.2558,190
12943.16.0.0/1943.16.0.1 to 43.16.31.25443.16.31.2558,190
13043.16.32.0/1943.16.32.1 to 43.16.63.25443.16.63.2558,190
13143.16.64.0/1943.16.64.1 to 43.16.95.25443.16.95.2558,190
13243.16.96.0/1943.16.96.1 to 43.16.127.25443.16.127.2558,190
13343.16.128.0/1943.16.128.1 to 43.16.159.25443.16.159.2558,190
13443.16.160.0/1943.16.160.1 to 43.16.191.25443.16.191.2558,190
13543.16.192.0/1943.16.192.1 to 43.16.223.25443.16.223.2558,190
13643.16.224.0/1943.16.224.1 to 43.16.255.25443.16.255.2558,190
13743.17.0.0/1943.17.0.1 to 43.17.31.25443.17.31.2558,190
13843.17.32.0/1943.17.32.1 to 43.17.63.25443.17.63.2558,190
13943.17.64.0/1943.17.64.1 to 43.17.95.25443.17.95.2558,190
14043.17.96.0/1943.17.96.1 to 43.17.127.25443.17.127.2558,190
14143.17.128.0/1943.17.128.1 to 43.17.159.25443.17.159.2558,190
14243.17.160.0/1943.17.160.1 to 43.17.191.25443.17.191.2558,190
14343.17.192.0/1943.17.192.1 to 43.17.223.25443.17.223.2558,190
14443.17.224.0/1943.17.224.1 to 43.17.255.25443.17.255.2558,190
14543.18.0.0/1943.18.0.1 to 43.18.31.25443.18.31.2558,190
14643.18.32.0/1943.18.32.1 to 43.18.63.25443.18.63.2558,190
14743.18.64.0/1943.18.64.1 to 43.18.95.25443.18.95.2558,190
14843.18.96.0/1943.18.96.1 to 43.18.127.25443.18.127.2558,190
14943.18.128.0/1943.18.128.1 to 43.18.159.25443.18.159.2558,190
15043.18.160.0/1943.18.160.1 to 43.18.191.25443.18.191.2558,190
15143.18.192.0/1943.18.192.1 to 43.18.223.25443.18.223.2558,190
15243.18.224.0/1943.18.224.1 to 43.18.255.25443.18.255.2558,190
15343.19.0.0/1943.19.0.1 to 43.19.31.25443.19.31.2558,190
15443.19.32.0/1943.19.32.1 to 43.19.63.25443.19.63.2558,190
15543.19.64.0/1943.19.64.1 to 43.19.95.25443.19.95.2558,190
15643.19.96.0/1943.19.96.1 to 43.19.127.25443.19.127.2558,190
15743.19.128.0/1943.19.128.1 to 43.19.159.25443.19.159.2558,190
15843.19.160.0/1943.19.160.1 to 43.19.191.25443.19.191.2558,190
15943.19.192.0/1943.19.192.1 to 43.19.223.25443.19.223.2558,190
16043.19.224.0/1943.19.224.1 to 43.19.255.25443.19.255.2558,190
16143.20.0.0/1943.20.0.1 to 43.20.31.25443.20.31.2558,190
16243.20.32.0/1943.20.32.1 to 43.20.63.25443.20.63.2558,190
16343.20.64.0/1943.20.64.1 to 43.20.95.25443.20.95.2558,190
16443.20.96.0/1943.20.96.1 to 43.20.127.25443.20.127.2558,190
16543.20.128.0/1943.20.128.1 to 43.20.159.25443.20.159.2558,190
16643.20.160.0/1943.20.160.1 to 43.20.191.25443.20.191.2558,190
16743.20.192.0/1943.20.192.1 to 43.20.223.25443.20.223.2558,190
16843.20.224.0/1943.20.224.1 to 43.20.255.25443.20.255.2558,190
16943.21.0.0/1943.21.0.1 to 43.21.31.25443.21.31.2558,190
17043.21.32.0/1943.21.32.1 to 43.21.63.25443.21.63.2558,190
17143.21.64.0/1943.21.64.1 to 43.21.95.25443.21.95.2558,190
17243.21.96.0/1943.21.96.1 to 43.21.127.25443.21.127.2558,190
17343.21.128.0/1943.21.128.1 to 43.21.159.25443.21.159.2558,190
17443.21.160.0/1943.21.160.1 to 43.21.191.25443.21.191.2558,190
17543.21.192.0/1943.21.192.1 to 43.21.223.25443.21.223.2558,190
17643.21.224.0/1943.21.224.1 to 43.21.255.25443.21.255.2558,190
17743.22.0.0/1943.22.0.1 to 43.22.31.25443.22.31.2558,190
17843.22.32.0/1943.22.32.1 to 43.22.63.25443.22.63.2558,190
17943.22.64.0/1943.22.64.1 to 43.22.95.25443.22.95.2558,190
18043.22.96.0/1943.22.96.1 to 43.22.127.25443.22.127.2558,190
18143.22.128.0/1943.22.128.1 to 43.22.159.25443.22.159.2558,190
18243.22.160.0/1943.22.160.1 to 43.22.191.25443.22.191.2558,190
18343.22.192.0/1943.22.192.1 to 43.22.223.25443.22.223.2558,190
18443.22.224.0/1943.22.224.1 to 43.22.255.25443.22.255.2558,190
18543.23.0.0/1943.23.0.1 to 43.23.31.25443.23.31.2558,190
18643.23.32.0/1943.23.32.1 to 43.23.63.25443.23.63.2558,190
18743.23.64.0/1943.23.64.1 to 43.23.95.25443.23.95.2558,190
18843.23.96.0/1943.23.96.1 to 43.23.127.25443.23.127.2558,190
18943.23.128.0/1943.23.128.1 to 43.23.159.25443.23.159.2558,190
19043.23.160.0/1943.23.160.1 to 43.23.191.25443.23.191.2558,190
19143.23.192.0/1943.23.192.1 to 43.23.223.25443.23.223.2558,190
19243.23.224.0/1943.23.224.1 to 43.23.255.25443.23.255.2558,190
19343.24.0.0/1943.24.0.1 to 43.24.31.25443.24.31.2558,190
19443.24.32.0/1943.24.32.1 to 43.24.63.25443.24.63.2558,190
19543.24.64.0/1943.24.64.1 to 43.24.95.25443.24.95.2558,190
19643.24.96.0/1943.24.96.1 to 43.24.127.25443.24.127.2558,190
19743.24.128.0/1943.24.128.1 to 43.24.159.25443.24.159.2558,190
19843.24.160.0/1943.24.160.1 to 43.24.191.25443.24.191.2558,190
19943.24.192.0/1943.24.192.1 to 43.24.223.25443.24.223.2558,190
20043.24.224.0/1943.24.224.1 to 43.24.255.25443.24.255.2558,190
20143.25.0.0/1943.25.0.1 to 43.25.31.25443.25.31.2558,190
20243.25.32.0/1943.25.32.1 to 43.25.63.25443.25.63.2558,190
20343.25.64.0/1943.25.64.1 to 43.25.95.25443.25.95.2558,190
20443.25.96.0/1943.25.96.1 to 43.25.127.25443.25.127.2558,190
20543.25.128.0/1943.25.128.1 to 43.25.159.25443.25.159.2558,190
20643.25.160.0/1943.25.160.1 to 43.25.191.25443.25.191.2558,190
20743.25.192.0/1943.25.192.1 to 43.25.223.25443.25.223.2558,190
20843.25.224.0/1943.25.224.1 to 43.25.255.25443.25.255.2558,190
20943.26.0.0/1943.26.0.1 to 43.26.31.25443.26.31.2558,190
21043.26.32.0/1943.26.32.1 to 43.26.63.25443.26.63.2558,190
21143.26.64.0/1943.26.64.1 to 43.26.95.25443.26.95.2558,190
21243.26.96.0/1943.26.96.1 to 43.26.127.25443.26.127.2558,190
21343.26.128.0/1943.26.128.1 to 43.26.159.25443.26.159.2558,190
21443.26.160.0/1943.26.160.1 to 43.26.191.25443.26.191.2558,190
21543.26.192.0/1943.26.192.1 to 43.26.223.25443.26.223.2558,190
21643.26.224.0/1943.26.224.1 to 43.26.255.25443.26.255.2558,190
21743.27.0.0/1943.27.0.1 to 43.27.31.25443.27.31.2558,190
21843.27.32.0/1943.27.32.1 to 43.27.63.25443.27.63.2558,190
21943.27.64.0/1943.27.64.1 to 43.27.95.25443.27.95.2558,190
22043.27.96.0/1943.27.96.1 to 43.27.127.25443.27.127.2558,190
22143.27.128.0/1943.27.128.1 to 43.27.159.25443.27.159.2558,190
22243.27.160.0/1943.27.160.1 to 43.27.191.25443.27.191.2558,190
22343.27.192.0/1943.27.192.1 to 43.27.223.25443.27.223.2558,190
22443.27.224.0/1943.27.224.1 to 43.27.255.25443.27.255.2558,190
22543.28.0.0/1943.28.0.1 to 43.28.31.25443.28.31.2558,190
22643.28.32.0/1943.28.32.1 to 43.28.63.25443.28.63.2558,190
22743.28.64.0/1943.28.64.1 to 43.28.95.25443.28.95.2558,190
22843.28.96.0/1943.28.96.1 to 43.28.127.25443.28.127.2558,190
22943.28.128.0/1943.28.128.1 to 43.28.159.25443.28.159.2558,190
23043.28.160.0/1943.28.160.1 to 43.28.191.25443.28.191.2558,190
23143.28.192.0/1943.28.192.1 to 43.28.223.25443.28.223.2558,190
23243.28.224.0/1943.28.224.1 to 43.28.255.25443.28.255.2558,190
23343.29.0.0/1943.29.0.1 to 43.29.31.25443.29.31.2558,190
23443.29.32.0/1943.29.32.1 to 43.29.63.25443.29.63.2558,190
23543.29.64.0/1943.29.64.1 to 43.29.95.25443.29.95.2558,190
23643.29.96.0/1943.29.96.1 to 43.29.127.25443.29.127.2558,190
23743.29.128.0/1943.29.128.1 to 43.29.159.25443.29.159.2558,190
23843.29.160.0/1943.29.160.1 to 43.29.191.25443.29.191.2558,190
23943.29.192.0/1943.29.192.1 to 43.29.223.25443.29.223.2558,190
24043.29.224.0/1943.29.224.1 to 43.29.255.25443.29.255.2558,190
24143.30.0.0/1943.30.0.1 to 43.30.31.25443.30.31.2558,190
24243.30.32.0/1943.30.32.1 to 43.30.63.25443.30.63.2558,190
24343.30.64.0/1943.30.64.1 to 43.30.95.25443.30.95.2558,190
24443.30.96.0/1943.30.96.1 to 43.30.127.25443.30.127.2558,190
24543.30.128.0/1943.30.128.1 to 43.30.159.25443.30.159.2558,190
24643.30.160.0/1943.30.160.1 to 43.30.191.25443.30.191.2558,190
24743.30.192.0/1943.30.192.1 to 43.30.223.25443.30.223.2558,190
24843.30.224.0/1943.30.224.1 to 43.30.255.25443.30.255.2558,190
24943.31.0.0/1943.31.0.1 to 43.31.31.25443.31.31.2558,190
25043.31.32.0/1943.31.32.1 to 43.31.63.25443.31.63.2558,190
25143.31.64.0/1943.31.64.1 to 43.31.95.25443.31.95.2558,190
25243.31.96.0/1943.31.96.1 to 43.31.127.25443.31.127.2558,190
25343.31.128.0/1943.31.128.1 to 43.31.159.25443.31.159.2558,190
25443.31.160.0/1943.31.160.1 to 43.31.191.25443.31.191.2558,190
25543.31.192.0/1943.31.192.1 to 43.31.223.25443.31.223.2558,190
25643.31.224.0/1943.31.224.1 to 43.31.255.25443.31.255.2558,190

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.