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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.

Network56.0.0.0/7
Usable hosts33,554,430
Subnet mask254.0.0.0
Addresses33,554,432
Network address
56.0.0.0
Broadcast address
57.255.255.255
First usable
56.0.0.1
Last usable
57.255.255.254
Usable hosts
33,554,430 (33,554,432 less the network and broadcast addresses)
Subnet mask
254.0.0.0
Wildcard mask
1.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/7
Type
Public public
Old class
A (default /8)
As numbers
Hex 38000000 · Integer 939524096 to 973078527
Reverse DNS zones
56.in-addr.arpa
57.in-addr.arpa
/7 is not on a 8-bit boundary, so it takes 2 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00111000.00000000.00000000.0000000056.0.0.0
Subnet mask11111110.00000000.00000000.00000000254.0.0.0
Network00111000.00000000.00000000.0000000056.0.0.0
Broadcast00111001.11111111.11111111.1111111157.255.255.255
Split into smaller subnets/18
/8 (2)/9 (4)/10 (8)/11 (16)/12 (32)/13 (64)/14 (128)/15 (256)/16 (512)/17 (1,024)/18 (2,048)/19 (4,096)

56.0.0.0/7 makes 2,048 subnets of /18; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
156.0.0.0/1856.0.0.1 to 56.0.63.25456.0.63.25516,382
256.0.64.0/1856.0.64.1 to 56.0.127.25456.0.127.25516,382
356.0.128.0/1856.0.128.1 to 56.0.191.25456.0.191.25516,382
456.0.192.0/1856.0.192.1 to 56.0.255.25456.0.255.25516,382
556.1.0.0/1856.1.0.1 to 56.1.63.25456.1.63.25516,382
656.1.64.0/1856.1.64.1 to 56.1.127.25456.1.127.25516,382
756.1.128.0/1856.1.128.1 to 56.1.191.25456.1.191.25516,382
856.1.192.0/1856.1.192.1 to 56.1.255.25456.1.255.25516,382
956.2.0.0/1856.2.0.1 to 56.2.63.25456.2.63.25516,382
1056.2.64.0/1856.2.64.1 to 56.2.127.25456.2.127.25516,382
1156.2.128.0/1856.2.128.1 to 56.2.191.25456.2.191.25516,382
1256.2.192.0/1856.2.192.1 to 56.2.255.25456.2.255.25516,382
1356.3.0.0/1856.3.0.1 to 56.3.63.25456.3.63.25516,382
1456.3.64.0/1856.3.64.1 to 56.3.127.25456.3.127.25516,382
1556.3.128.0/1856.3.128.1 to 56.3.191.25456.3.191.25516,382
1656.3.192.0/1856.3.192.1 to 56.3.255.25456.3.255.25516,382
1756.4.0.0/1856.4.0.1 to 56.4.63.25456.4.63.25516,382
1856.4.64.0/1856.4.64.1 to 56.4.127.25456.4.127.25516,382
1956.4.128.0/1856.4.128.1 to 56.4.191.25456.4.191.25516,382
2056.4.192.0/1856.4.192.1 to 56.4.255.25456.4.255.25516,382
2156.5.0.0/1856.5.0.1 to 56.5.63.25456.5.63.25516,382
2256.5.64.0/1856.5.64.1 to 56.5.127.25456.5.127.25516,382
2356.5.128.0/1856.5.128.1 to 56.5.191.25456.5.191.25516,382
2456.5.192.0/1856.5.192.1 to 56.5.255.25456.5.255.25516,382
2556.6.0.0/1856.6.0.1 to 56.6.63.25456.6.63.25516,382
2656.6.64.0/1856.6.64.1 to 56.6.127.25456.6.127.25516,382
2756.6.128.0/1856.6.128.1 to 56.6.191.25456.6.191.25516,382
2856.6.192.0/1856.6.192.1 to 56.6.255.25456.6.255.25516,382
2956.7.0.0/1856.7.0.1 to 56.7.63.25456.7.63.25516,382
3056.7.64.0/1856.7.64.1 to 56.7.127.25456.7.127.25516,382
3156.7.128.0/1856.7.128.1 to 56.7.191.25456.7.191.25516,382
3256.7.192.0/1856.7.192.1 to 56.7.255.25456.7.255.25516,382
3356.8.0.0/1856.8.0.1 to 56.8.63.25456.8.63.25516,382
3456.8.64.0/1856.8.64.1 to 56.8.127.25456.8.127.25516,382
3556.8.128.0/1856.8.128.1 to 56.8.191.25456.8.191.25516,382
3656.8.192.0/1856.8.192.1 to 56.8.255.25456.8.255.25516,382
3756.9.0.0/1856.9.0.1 to 56.9.63.25456.9.63.25516,382
3856.9.64.0/1856.9.64.1 to 56.9.127.25456.9.127.25516,382
3956.9.128.0/1856.9.128.1 to 56.9.191.25456.9.191.25516,382
4056.9.192.0/1856.9.192.1 to 56.9.255.25456.9.255.25516,382
4156.10.0.0/1856.10.0.1 to 56.10.63.25456.10.63.25516,382
4256.10.64.0/1856.10.64.1 to 56.10.127.25456.10.127.25516,382
4356.10.128.0/1856.10.128.1 to 56.10.191.25456.10.191.25516,382
4456.10.192.0/1856.10.192.1 to 56.10.255.25456.10.255.25516,382
4556.11.0.0/1856.11.0.1 to 56.11.63.25456.11.63.25516,382
4656.11.64.0/1856.11.64.1 to 56.11.127.25456.11.127.25516,382
4756.11.128.0/1856.11.128.1 to 56.11.191.25456.11.191.25516,382
4856.11.192.0/1856.11.192.1 to 56.11.255.25456.11.255.25516,382
4956.12.0.0/1856.12.0.1 to 56.12.63.25456.12.63.25516,382
5056.12.64.0/1856.12.64.1 to 56.12.127.25456.12.127.25516,382
5156.12.128.0/1856.12.128.1 to 56.12.191.25456.12.191.25516,382
5256.12.192.0/1856.12.192.1 to 56.12.255.25456.12.255.25516,382
5356.13.0.0/1856.13.0.1 to 56.13.63.25456.13.63.25516,382
5456.13.64.0/1856.13.64.1 to 56.13.127.25456.13.127.25516,382
5556.13.128.0/1856.13.128.1 to 56.13.191.25456.13.191.25516,382
5656.13.192.0/1856.13.192.1 to 56.13.255.25456.13.255.25516,382
5756.14.0.0/1856.14.0.1 to 56.14.63.25456.14.63.25516,382
5856.14.64.0/1856.14.64.1 to 56.14.127.25456.14.127.25516,382
5956.14.128.0/1856.14.128.1 to 56.14.191.25456.14.191.25516,382
6056.14.192.0/1856.14.192.1 to 56.14.255.25456.14.255.25516,382
6156.15.0.0/1856.15.0.1 to 56.15.63.25456.15.63.25516,382
6256.15.64.0/1856.15.64.1 to 56.15.127.25456.15.127.25516,382
6356.15.128.0/1856.15.128.1 to 56.15.191.25456.15.191.25516,382
6456.15.192.0/1856.15.192.1 to 56.15.255.25456.15.255.25516,382
6556.16.0.0/1856.16.0.1 to 56.16.63.25456.16.63.25516,382
6656.16.64.0/1856.16.64.1 to 56.16.127.25456.16.127.25516,382
6756.16.128.0/1856.16.128.1 to 56.16.191.25456.16.191.25516,382
6856.16.192.0/1856.16.192.1 to 56.16.255.25456.16.255.25516,382
6956.17.0.0/1856.17.0.1 to 56.17.63.25456.17.63.25516,382
7056.17.64.0/1856.17.64.1 to 56.17.127.25456.17.127.25516,382
7156.17.128.0/1856.17.128.1 to 56.17.191.25456.17.191.25516,382
7256.17.192.0/1856.17.192.1 to 56.17.255.25456.17.255.25516,382
7356.18.0.0/1856.18.0.1 to 56.18.63.25456.18.63.25516,382
7456.18.64.0/1856.18.64.1 to 56.18.127.25456.18.127.25516,382
7556.18.128.0/1856.18.128.1 to 56.18.191.25456.18.191.25516,382
7656.18.192.0/1856.18.192.1 to 56.18.255.25456.18.255.25516,382
7756.19.0.0/1856.19.0.1 to 56.19.63.25456.19.63.25516,382
7856.19.64.0/1856.19.64.1 to 56.19.127.25456.19.127.25516,382
7956.19.128.0/1856.19.128.1 to 56.19.191.25456.19.191.25516,382
8056.19.192.0/1856.19.192.1 to 56.19.255.25456.19.255.25516,382
8156.20.0.0/1856.20.0.1 to 56.20.63.25456.20.63.25516,382
8256.20.64.0/1856.20.64.1 to 56.20.127.25456.20.127.25516,382
8356.20.128.0/1856.20.128.1 to 56.20.191.25456.20.191.25516,382
8456.20.192.0/1856.20.192.1 to 56.20.255.25456.20.255.25516,382
8556.21.0.0/1856.21.0.1 to 56.21.63.25456.21.63.25516,382
8656.21.64.0/1856.21.64.1 to 56.21.127.25456.21.127.25516,382
8756.21.128.0/1856.21.128.1 to 56.21.191.25456.21.191.25516,382
8856.21.192.0/1856.21.192.1 to 56.21.255.25456.21.255.25516,382
8956.22.0.0/1856.22.0.1 to 56.22.63.25456.22.63.25516,382
9056.22.64.0/1856.22.64.1 to 56.22.127.25456.22.127.25516,382
9156.22.128.0/1856.22.128.1 to 56.22.191.25456.22.191.25516,382
9256.22.192.0/1856.22.192.1 to 56.22.255.25456.22.255.25516,382
9356.23.0.0/1856.23.0.1 to 56.23.63.25456.23.63.25516,382
9456.23.64.0/1856.23.64.1 to 56.23.127.25456.23.127.25516,382
9556.23.128.0/1856.23.128.1 to 56.23.191.25456.23.191.25516,382
9656.23.192.0/1856.23.192.1 to 56.23.255.25456.23.255.25516,382
9756.24.0.0/1856.24.0.1 to 56.24.63.25456.24.63.25516,382
9856.24.64.0/1856.24.64.1 to 56.24.127.25456.24.127.25516,382
9956.24.128.0/1856.24.128.1 to 56.24.191.25456.24.191.25516,382
10056.24.192.0/1856.24.192.1 to 56.24.255.25456.24.255.25516,382
10156.25.0.0/1856.25.0.1 to 56.25.63.25456.25.63.25516,382
10256.25.64.0/1856.25.64.1 to 56.25.127.25456.25.127.25516,382
10356.25.128.0/1856.25.128.1 to 56.25.191.25456.25.191.25516,382
10456.25.192.0/1856.25.192.1 to 56.25.255.25456.25.255.25516,382
10556.26.0.0/1856.26.0.1 to 56.26.63.25456.26.63.25516,382
10656.26.64.0/1856.26.64.1 to 56.26.127.25456.26.127.25516,382
10756.26.128.0/1856.26.128.1 to 56.26.191.25456.26.191.25516,382
10856.26.192.0/1856.26.192.1 to 56.26.255.25456.26.255.25516,382
10956.27.0.0/1856.27.0.1 to 56.27.63.25456.27.63.25516,382
11056.27.64.0/1856.27.64.1 to 56.27.127.25456.27.127.25516,382
11156.27.128.0/1856.27.128.1 to 56.27.191.25456.27.191.25516,382
11256.27.192.0/1856.27.192.1 to 56.27.255.25456.27.255.25516,382
11356.28.0.0/1856.28.0.1 to 56.28.63.25456.28.63.25516,382
11456.28.64.0/1856.28.64.1 to 56.28.127.25456.28.127.25516,382
11556.28.128.0/1856.28.128.1 to 56.28.191.25456.28.191.25516,382
11656.28.192.0/1856.28.192.1 to 56.28.255.25456.28.255.25516,382
11756.29.0.0/1856.29.0.1 to 56.29.63.25456.29.63.25516,382
11856.29.64.0/1856.29.64.1 to 56.29.127.25456.29.127.25516,382
11956.29.128.0/1856.29.128.1 to 56.29.191.25456.29.191.25516,382
12056.29.192.0/1856.29.192.1 to 56.29.255.25456.29.255.25516,382
12156.30.0.0/1856.30.0.1 to 56.30.63.25456.30.63.25516,382
12256.30.64.0/1856.30.64.1 to 56.30.127.25456.30.127.25516,382
12356.30.128.0/1856.30.128.1 to 56.30.191.25456.30.191.25516,382
12456.30.192.0/1856.30.192.1 to 56.30.255.25456.30.255.25516,382
12556.31.0.0/1856.31.0.1 to 56.31.63.25456.31.63.25516,382
12656.31.64.0/1856.31.64.1 to 56.31.127.25456.31.127.25516,382
12756.31.128.0/1856.31.128.1 to 56.31.191.25456.31.191.25516,382
12856.31.192.0/1856.31.192.1 to 56.31.255.25456.31.255.25516,382
12956.32.0.0/1856.32.0.1 to 56.32.63.25456.32.63.25516,382
13056.32.64.0/1856.32.64.1 to 56.32.127.25456.32.127.25516,382
13156.32.128.0/1856.32.128.1 to 56.32.191.25456.32.191.25516,382
13256.32.192.0/1856.32.192.1 to 56.32.255.25456.32.255.25516,382
13356.33.0.0/1856.33.0.1 to 56.33.63.25456.33.63.25516,382
13456.33.64.0/1856.33.64.1 to 56.33.127.25456.33.127.25516,382
13556.33.128.0/1856.33.128.1 to 56.33.191.25456.33.191.25516,382
13656.33.192.0/1856.33.192.1 to 56.33.255.25456.33.255.25516,382
13756.34.0.0/1856.34.0.1 to 56.34.63.25456.34.63.25516,382
13856.34.64.0/1856.34.64.1 to 56.34.127.25456.34.127.25516,382
13956.34.128.0/1856.34.128.1 to 56.34.191.25456.34.191.25516,382
14056.34.192.0/1856.34.192.1 to 56.34.255.25456.34.255.25516,382
14156.35.0.0/1856.35.0.1 to 56.35.63.25456.35.63.25516,382
14256.35.64.0/1856.35.64.1 to 56.35.127.25456.35.127.25516,382
14356.35.128.0/1856.35.128.1 to 56.35.191.25456.35.191.25516,382
14456.35.192.0/1856.35.192.1 to 56.35.255.25456.35.255.25516,382
14556.36.0.0/1856.36.0.1 to 56.36.63.25456.36.63.25516,382
14656.36.64.0/1856.36.64.1 to 56.36.127.25456.36.127.25516,382
14756.36.128.0/1856.36.128.1 to 56.36.191.25456.36.191.25516,382
14856.36.192.0/1856.36.192.1 to 56.36.255.25456.36.255.25516,382
14956.37.0.0/1856.37.0.1 to 56.37.63.25456.37.63.25516,382
15056.37.64.0/1856.37.64.1 to 56.37.127.25456.37.127.25516,382
15156.37.128.0/1856.37.128.1 to 56.37.191.25456.37.191.25516,382
15256.37.192.0/1856.37.192.1 to 56.37.255.25456.37.255.25516,382
15356.38.0.0/1856.38.0.1 to 56.38.63.25456.38.63.25516,382
15456.38.64.0/1856.38.64.1 to 56.38.127.25456.38.127.25516,382
15556.38.128.0/1856.38.128.1 to 56.38.191.25456.38.191.25516,382
15656.38.192.0/1856.38.192.1 to 56.38.255.25456.38.255.25516,382
15756.39.0.0/1856.39.0.1 to 56.39.63.25456.39.63.25516,382
15856.39.64.0/1856.39.64.1 to 56.39.127.25456.39.127.25516,382
15956.39.128.0/1856.39.128.1 to 56.39.191.25456.39.191.25516,382
16056.39.192.0/1856.39.192.1 to 56.39.255.25456.39.255.25516,382
16156.40.0.0/1856.40.0.1 to 56.40.63.25456.40.63.25516,382
16256.40.64.0/1856.40.64.1 to 56.40.127.25456.40.127.25516,382
16356.40.128.0/1856.40.128.1 to 56.40.191.25456.40.191.25516,382
16456.40.192.0/1856.40.192.1 to 56.40.255.25456.40.255.25516,382
16556.41.0.0/1856.41.0.1 to 56.41.63.25456.41.63.25516,382
16656.41.64.0/1856.41.64.1 to 56.41.127.25456.41.127.25516,382
16756.41.128.0/1856.41.128.1 to 56.41.191.25456.41.191.25516,382
16856.41.192.0/1856.41.192.1 to 56.41.255.25456.41.255.25516,382
16956.42.0.0/1856.42.0.1 to 56.42.63.25456.42.63.25516,382
17056.42.64.0/1856.42.64.1 to 56.42.127.25456.42.127.25516,382
17156.42.128.0/1856.42.128.1 to 56.42.191.25456.42.191.25516,382
17256.42.192.0/1856.42.192.1 to 56.42.255.25456.42.255.25516,382
17356.43.0.0/1856.43.0.1 to 56.43.63.25456.43.63.25516,382
17456.43.64.0/1856.43.64.1 to 56.43.127.25456.43.127.25516,382
17556.43.128.0/1856.43.128.1 to 56.43.191.25456.43.191.25516,382
17656.43.192.0/1856.43.192.1 to 56.43.255.25456.43.255.25516,382
17756.44.0.0/1856.44.0.1 to 56.44.63.25456.44.63.25516,382
17856.44.64.0/1856.44.64.1 to 56.44.127.25456.44.127.25516,382
17956.44.128.0/1856.44.128.1 to 56.44.191.25456.44.191.25516,382
18056.44.192.0/1856.44.192.1 to 56.44.255.25456.44.255.25516,382
18156.45.0.0/1856.45.0.1 to 56.45.63.25456.45.63.25516,382
18256.45.64.0/1856.45.64.1 to 56.45.127.25456.45.127.25516,382
18356.45.128.0/1856.45.128.1 to 56.45.191.25456.45.191.25516,382
18456.45.192.0/1856.45.192.1 to 56.45.255.25456.45.255.25516,382
18556.46.0.0/1856.46.0.1 to 56.46.63.25456.46.63.25516,382
18656.46.64.0/1856.46.64.1 to 56.46.127.25456.46.127.25516,382
18756.46.128.0/1856.46.128.1 to 56.46.191.25456.46.191.25516,382
18856.46.192.0/1856.46.192.1 to 56.46.255.25456.46.255.25516,382
18956.47.0.0/1856.47.0.1 to 56.47.63.25456.47.63.25516,382
19056.47.64.0/1856.47.64.1 to 56.47.127.25456.47.127.25516,382
19156.47.128.0/1856.47.128.1 to 56.47.191.25456.47.191.25516,382
19256.47.192.0/1856.47.192.1 to 56.47.255.25456.47.255.25516,382
19356.48.0.0/1856.48.0.1 to 56.48.63.25456.48.63.25516,382
19456.48.64.0/1856.48.64.1 to 56.48.127.25456.48.127.25516,382
19556.48.128.0/1856.48.128.1 to 56.48.191.25456.48.191.25516,382
19656.48.192.0/1856.48.192.1 to 56.48.255.25456.48.255.25516,382
19756.49.0.0/1856.49.0.1 to 56.49.63.25456.49.63.25516,382
19856.49.64.0/1856.49.64.1 to 56.49.127.25456.49.127.25516,382
19956.49.128.0/1856.49.128.1 to 56.49.191.25456.49.191.25516,382
20056.49.192.0/1856.49.192.1 to 56.49.255.25456.49.255.25516,382
20156.50.0.0/1856.50.0.1 to 56.50.63.25456.50.63.25516,382
20256.50.64.0/1856.50.64.1 to 56.50.127.25456.50.127.25516,382
20356.50.128.0/1856.50.128.1 to 56.50.191.25456.50.191.25516,382
20456.50.192.0/1856.50.192.1 to 56.50.255.25456.50.255.25516,382
20556.51.0.0/1856.51.0.1 to 56.51.63.25456.51.63.25516,382
20656.51.64.0/1856.51.64.1 to 56.51.127.25456.51.127.25516,382
20756.51.128.0/1856.51.128.1 to 56.51.191.25456.51.191.25516,382
20856.51.192.0/1856.51.192.1 to 56.51.255.25456.51.255.25516,382
20956.52.0.0/1856.52.0.1 to 56.52.63.25456.52.63.25516,382
21056.52.64.0/1856.52.64.1 to 56.52.127.25456.52.127.25516,382
21156.52.128.0/1856.52.128.1 to 56.52.191.25456.52.191.25516,382
21256.52.192.0/1856.52.192.1 to 56.52.255.25456.52.255.25516,382
21356.53.0.0/1856.53.0.1 to 56.53.63.25456.53.63.25516,382
21456.53.64.0/1856.53.64.1 to 56.53.127.25456.53.127.25516,382
21556.53.128.0/1856.53.128.1 to 56.53.191.25456.53.191.25516,382
21656.53.192.0/1856.53.192.1 to 56.53.255.25456.53.255.25516,382
21756.54.0.0/1856.54.0.1 to 56.54.63.25456.54.63.25516,382
21856.54.64.0/1856.54.64.1 to 56.54.127.25456.54.127.25516,382
21956.54.128.0/1856.54.128.1 to 56.54.191.25456.54.191.25516,382
22056.54.192.0/1856.54.192.1 to 56.54.255.25456.54.255.25516,382
22156.55.0.0/1856.55.0.1 to 56.55.63.25456.55.63.25516,382
22256.55.64.0/1856.55.64.1 to 56.55.127.25456.55.127.25516,382
22356.55.128.0/1856.55.128.1 to 56.55.191.25456.55.191.25516,382
22456.55.192.0/1856.55.192.1 to 56.55.255.25456.55.255.25516,382
22556.56.0.0/1856.56.0.1 to 56.56.63.25456.56.63.25516,382
22656.56.64.0/1856.56.64.1 to 56.56.127.25456.56.127.25516,382
22756.56.128.0/1856.56.128.1 to 56.56.191.25456.56.191.25516,382
22856.56.192.0/1856.56.192.1 to 56.56.255.25456.56.255.25516,382
22956.57.0.0/1856.57.0.1 to 56.57.63.25456.57.63.25516,382
23056.57.64.0/1856.57.64.1 to 56.57.127.25456.57.127.25516,382
23156.57.128.0/1856.57.128.1 to 56.57.191.25456.57.191.25516,382
23256.57.192.0/1856.57.192.1 to 56.57.255.25456.57.255.25516,382
23356.58.0.0/1856.58.0.1 to 56.58.63.25456.58.63.25516,382
23456.58.64.0/1856.58.64.1 to 56.58.127.25456.58.127.25516,382
23556.58.128.0/1856.58.128.1 to 56.58.191.25456.58.191.25516,382
23656.58.192.0/1856.58.192.1 to 56.58.255.25456.58.255.25516,382
23756.59.0.0/1856.59.0.1 to 56.59.63.25456.59.63.25516,382
23856.59.64.0/1856.59.64.1 to 56.59.127.25456.59.127.25516,382
23956.59.128.0/1856.59.128.1 to 56.59.191.25456.59.191.25516,382
24056.59.192.0/1856.59.192.1 to 56.59.255.25456.59.255.25516,382
24156.60.0.0/1856.60.0.1 to 56.60.63.25456.60.63.25516,382
24256.60.64.0/1856.60.64.1 to 56.60.127.25456.60.127.25516,382
24356.60.128.0/1856.60.128.1 to 56.60.191.25456.60.191.25516,382
24456.60.192.0/1856.60.192.1 to 56.60.255.25456.60.255.25516,382
24556.61.0.0/1856.61.0.1 to 56.61.63.25456.61.63.25516,382
24656.61.64.0/1856.61.64.1 to 56.61.127.25456.61.127.25516,382
24756.61.128.0/1856.61.128.1 to 56.61.191.25456.61.191.25516,382
24856.61.192.0/1856.61.192.1 to 56.61.255.25456.61.255.25516,382
24956.62.0.0/1856.62.0.1 to 56.62.63.25456.62.63.25516,382
25056.62.64.0/1856.62.64.1 to 56.62.127.25456.62.127.25516,382
25156.62.128.0/1856.62.128.1 to 56.62.191.25456.62.191.25516,382
25256.62.192.0/1856.62.192.1 to 56.62.255.25456.62.255.25516,382
25356.63.0.0/1856.63.0.1 to 56.63.63.25456.63.63.25516,382
25456.63.64.0/1856.63.64.1 to 56.63.127.25456.63.127.25516,382
25556.63.128.0/1856.63.128.1 to 56.63.191.25456.63.191.25516,382
25656.63.192.0/1856.63.192.1 to 56.63.255.25456.63.255.25516,382

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.