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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.

Network12.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
12.0.0.0
Broadcast address
12.255.255.255
First usable
12.0.0.1
Last usable
12.255.255.254
Usable hosts
16,777,214 (16,777,216 less the network and broadcast addresses)
Subnet mask
255.0.0.0
Wildcard mask
0.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/8
Type
Public public
Old class
A (default /8)
As numbers
Hex 0C000000 · Integer 201326592 to 218103807
Reverse DNS zone
12.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00001100..00000000.00000000.0000000012.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network00001100..00000000.00000000.0000000012.0.0.0
Broadcast00001100..11111111.11111111.1111111112.255.255.255
Split into smaller subnets/18
/9 (2)/10 (4)/11 (8)/12 (16)/13 (32)/14 (64)/15 (128)/16 (256)/17 (512)/18 (1,024)/19 (2,048)/20 (4,096)

12.0.0.0/8 makes 1,024 subnets of /18; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
112.0.0.0/1812.0.0.1 to 12.0.63.25412.0.63.25516,382
212.0.64.0/1812.0.64.1 to 12.0.127.25412.0.127.25516,382
312.0.128.0/1812.0.128.1 to 12.0.191.25412.0.191.25516,382
412.0.192.0/1812.0.192.1 to 12.0.255.25412.0.255.25516,382
512.1.0.0/1812.1.0.1 to 12.1.63.25412.1.63.25516,382
612.1.64.0/1812.1.64.1 to 12.1.127.25412.1.127.25516,382
712.1.128.0/1812.1.128.1 to 12.1.191.25412.1.191.25516,382
812.1.192.0/1812.1.192.1 to 12.1.255.25412.1.255.25516,382
912.2.0.0/1812.2.0.1 to 12.2.63.25412.2.63.25516,382
1012.2.64.0/1812.2.64.1 to 12.2.127.25412.2.127.25516,382
1112.2.128.0/1812.2.128.1 to 12.2.191.25412.2.191.25516,382
1212.2.192.0/1812.2.192.1 to 12.2.255.25412.2.255.25516,382
1312.3.0.0/1812.3.0.1 to 12.3.63.25412.3.63.25516,382
1412.3.64.0/1812.3.64.1 to 12.3.127.25412.3.127.25516,382
1512.3.128.0/1812.3.128.1 to 12.3.191.25412.3.191.25516,382
1612.3.192.0/1812.3.192.1 to 12.3.255.25412.3.255.25516,382
1712.4.0.0/1812.4.0.1 to 12.4.63.25412.4.63.25516,382
1812.4.64.0/1812.4.64.1 to 12.4.127.25412.4.127.25516,382
1912.4.128.0/1812.4.128.1 to 12.4.191.25412.4.191.25516,382
2012.4.192.0/1812.4.192.1 to 12.4.255.25412.4.255.25516,382
2112.5.0.0/1812.5.0.1 to 12.5.63.25412.5.63.25516,382
2212.5.64.0/1812.5.64.1 to 12.5.127.25412.5.127.25516,382
2312.5.128.0/1812.5.128.1 to 12.5.191.25412.5.191.25516,382
2412.5.192.0/1812.5.192.1 to 12.5.255.25412.5.255.25516,382
2512.6.0.0/1812.6.0.1 to 12.6.63.25412.6.63.25516,382
2612.6.64.0/1812.6.64.1 to 12.6.127.25412.6.127.25516,382
2712.6.128.0/1812.6.128.1 to 12.6.191.25412.6.191.25516,382
2812.6.192.0/1812.6.192.1 to 12.6.255.25412.6.255.25516,382
2912.7.0.0/1812.7.0.1 to 12.7.63.25412.7.63.25516,382
3012.7.64.0/1812.7.64.1 to 12.7.127.25412.7.127.25516,382
3112.7.128.0/1812.7.128.1 to 12.7.191.25412.7.191.25516,382
3212.7.192.0/1812.7.192.1 to 12.7.255.25412.7.255.25516,382
3312.8.0.0/1812.8.0.1 to 12.8.63.25412.8.63.25516,382
3412.8.64.0/1812.8.64.1 to 12.8.127.25412.8.127.25516,382
3512.8.128.0/1812.8.128.1 to 12.8.191.25412.8.191.25516,382
3612.8.192.0/1812.8.192.1 to 12.8.255.25412.8.255.25516,382
3712.9.0.0/1812.9.0.1 to 12.9.63.25412.9.63.25516,382
3812.9.64.0/1812.9.64.1 to 12.9.127.25412.9.127.25516,382
3912.9.128.0/1812.9.128.1 to 12.9.191.25412.9.191.25516,382
4012.9.192.0/1812.9.192.1 to 12.9.255.25412.9.255.25516,382
4112.10.0.0/1812.10.0.1 to 12.10.63.25412.10.63.25516,382
4212.10.64.0/1812.10.64.1 to 12.10.127.25412.10.127.25516,382
4312.10.128.0/1812.10.128.1 to 12.10.191.25412.10.191.25516,382
4412.10.192.0/1812.10.192.1 to 12.10.255.25412.10.255.25516,382
4512.11.0.0/1812.11.0.1 to 12.11.63.25412.11.63.25516,382
4612.11.64.0/1812.11.64.1 to 12.11.127.25412.11.127.25516,382
4712.11.128.0/1812.11.128.1 to 12.11.191.25412.11.191.25516,382
4812.11.192.0/1812.11.192.1 to 12.11.255.25412.11.255.25516,382
4912.12.0.0/1812.12.0.1 to 12.12.63.25412.12.63.25516,382
5012.12.64.0/1812.12.64.1 to 12.12.127.25412.12.127.25516,382
5112.12.128.0/1812.12.128.1 to 12.12.191.25412.12.191.25516,382
5212.12.192.0/1812.12.192.1 to 12.12.255.25412.12.255.25516,382
5312.13.0.0/1812.13.0.1 to 12.13.63.25412.13.63.25516,382
5412.13.64.0/1812.13.64.1 to 12.13.127.25412.13.127.25516,382
5512.13.128.0/1812.13.128.1 to 12.13.191.25412.13.191.25516,382
5612.13.192.0/1812.13.192.1 to 12.13.255.25412.13.255.25516,382
5712.14.0.0/1812.14.0.1 to 12.14.63.25412.14.63.25516,382
5812.14.64.0/1812.14.64.1 to 12.14.127.25412.14.127.25516,382
5912.14.128.0/1812.14.128.1 to 12.14.191.25412.14.191.25516,382
6012.14.192.0/1812.14.192.1 to 12.14.255.25412.14.255.25516,382
6112.15.0.0/1812.15.0.1 to 12.15.63.25412.15.63.25516,382
6212.15.64.0/1812.15.64.1 to 12.15.127.25412.15.127.25516,382
6312.15.128.0/1812.15.128.1 to 12.15.191.25412.15.191.25516,382
6412.15.192.0/1812.15.192.1 to 12.15.255.25412.15.255.25516,382
6512.16.0.0/1812.16.0.1 to 12.16.63.25412.16.63.25516,382
6612.16.64.0/1812.16.64.1 to 12.16.127.25412.16.127.25516,382
6712.16.128.0/1812.16.128.1 to 12.16.191.25412.16.191.25516,382
6812.16.192.0/1812.16.192.1 to 12.16.255.25412.16.255.25516,382
6912.17.0.0/1812.17.0.1 to 12.17.63.25412.17.63.25516,382
7012.17.64.0/1812.17.64.1 to 12.17.127.25412.17.127.25516,382
7112.17.128.0/1812.17.128.1 to 12.17.191.25412.17.191.25516,382
7212.17.192.0/1812.17.192.1 to 12.17.255.25412.17.255.25516,382
7312.18.0.0/1812.18.0.1 to 12.18.63.25412.18.63.25516,382
7412.18.64.0/1812.18.64.1 to 12.18.127.25412.18.127.25516,382
7512.18.128.0/1812.18.128.1 to 12.18.191.25412.18.191.25516,382
7612.18.192.0/1812.18.192.1 to 12.18.255.25412.18.255.25516,382
7712.19.0.0/1812.19.0.1 to 12.19.63.25412.19.63.25516,382
7812.19.64.0/1812.19.64.1 to 12.19.127.25412.19.127.25516,382
7912.19.128.0/1812.19.128.1 to 12.19.191.25412.19.191.25516,382
8012.19.192.0/1812.19.192.1 to 12.19.255.25412.19.255.25516,382
8112.20.0.0/1812.20.0.1 to 12.20.63.25412.20.63.25516,382
8212.20.64.0/1812.20.64.1 to 12.20.127.25412.20.127.25516,382
8312.20.128.0/1812.20.128.1 to 12.20.191.25412.20.191.25516,382
8412.20.192.0/1812.20.192.1 to 12.20.255.25412.20.255.25516,382
8512.21.0.0/1812.21.0.1 to 12.21.63.25412.21.63.25516,382
8612.21.64.0/1812.21.64.1 to 12.21.127.25412.21.127.25516,382
8712.21.128.0/1812.21.128.1 to 12.21.191.25412.21.191.25516,382
8812.21.192.0/1812.21.192.1 to 12.21.255.25412.21.255.25516,382
8912.22.0.0/1812.22.0.1 to 12.22.63.25412.22.63.25516,382
9012.22.64.0/1812.22.64.1 to 12.22.127.25412.22.127.25516,382
9112.22.128.0/1812.22.128.1 to 12.22.191.25412.22.191.25516,382
9212.22.192.0/1812.22.192.1 to 12.22.255.25412.22.255.25516,382
9312.23.0.0/1812.23.0.1 to 12.23.63.25412.23.63.25516,382
9412.23.64.0/1812.23.64.1 to 12.23.127.25412.23.127.25516,382
9512.23.128.0/1812.23.128.1 to 12.23.191.25412.23.191.25516,382
9612.23.192.0/1812.23.192.1 to 12.23.255.25412.23.255.25516,382
9712.24.0.0/1812.24.0.1 to 12.24.63.25412.24.63.25516,382
9812.24.64.0/1812.24.64.1 to 12.24.127.25412.24.127.25516,382
9912.24.128.0/1812.24.128.1 to 12.24.191.25412.24.191.25516,382
10012.24.192.0/1812.24.192.1 to 12.24.255.25412.24.255.25516,382
10112.25.0.0/1812.25.0.1 to 12.25.63.25412.25.63.25516,382
10212.25.64.0/1812.25.64.1 to 12.25.127.25412.25.127.25516,382
10312.25.128.0/1812.25.128.1 to 12.25.191.25412.25.191.25516,382
10412.25.192.0/1812.25.192.1 to 12.25.255.25412.25.255.25516,382
10512.26.0.0/1812.26.0.1 to 12.26.63.25412.26.63.25516,382
10612.26.64.0/1812.26.64.1 to 12.26.127.25412.26.127.25516,382
10712.26.128.0/1812.26.128.1 to 12.26.191.25412.26.191.25516,382
10812.26.192.0/1812.26.192.1 to 12.26.255.25412.26.255.25516,382
10912.27.0.0/1812.27.0.1 to 12.27.63.25412.27.63.25516,382
11012.27.64.0/1812.27.64.1 to 12.27.127.25412.27.127.25516,382
11112.27.128.0/1812.27.128.1 to 12.27.191.25412.27.191.25516,382
11212.27.192.0/1812.27.192.1 to 12.27.255.25412.27.255.25516,382
11312.28.0.0/1812.28.0.1 to 12.28.63.25412.28.63.25516,382
11412.28.64.0/1812.28.64.1 to 12.28.127.25412.28.127.25516,382
11512.28.128.0/1812.28.128.1 to 12.28.191.25412.28.191.25516,382
11612.28.192.0/1812.28.192.1 to 12.28.255.25412.28.255.25516,382
11712.29.0.0/1812.29.0.1 to 12.29.63.25412.29.63.25516,382
11812.29.64.0/1812.29.64.1 to 12.29.127.25412.29.127.25516,382
11912.29.128.0/1812.29.128.1 to 12.29.191.25412.29.191.25516,382
12012.29.192.0/1812.29.192.1 to 12.29.255.25412.29.255.25516,382
12112.30.0.0/1812.30.0.1 to 12.30.63.25412.30.63.25516,382
12212.30.64.0/1812.30.64.1 to 12.30.127.25412.30.127.25516,382
12312.30.128.0/1812.30.128.1 to 12.30.191.25412.30.191.25516,382
12412.30.192.0/1812.30.192.1 to 12.30.255.25412.30.255.25516,382
12512.31.0.0/1812.31.0.1 to 12.31.63.25412.31.63.25516,382
12612.31.64.0/1812.31.64.1 to 12.31.127.25412.31.127.25516,382
12712.31.128.0/1812.31.128.1 to 12.31.191.25412.31.191.25516,382
12812.31.192.0/1812.31.192.1 to 12.31.255.25412.31.255.25516,382
12912.32.0.0/1812.32.0.1 to 12.32.63.25412.32.63.25516,382
13012.32.64.0/1812.32.64.1 to 12.32.127.25412.32.127.25516,382
13112.32.128.0/1812.32.128.1 to 12.32.191.25412.32.191.25516,382
13212.32.192.0/1812.32.192.1 to 12.32.255.25412.32.255.25516,382
13312.33.0.0/1812.33.0.1 to 12.33.63.25412.33.63.25516,382
13412.33.64.0/1812.33.64.1 to 12.33.127.25412.33.127.25516,382
13512.33.128.0/1812.33.128.1 to 12.33.191.25412.33.191.25516,382
13612.33.192.0/1812.33.192.1 to 12.33.255.25412.33.255.25516,382
13712.34.0.0/1812.34.0.1 to 12.34.63.25412.34.63.25516,382
13812.34.64.0/1812.34.64.1 to 12.34.127.25412.34.127.25516,382
13912.34.128.0/1812.34.128.1 to 12.34.191.25412.34.191.25516,382
14012.34.192.0/1812.34.192.1 to 12.34.255.25412.34.255.25516,382
14112.35.0.0/1812.35.0.1 to 12.35.63.25412.35.63.25516,382
14212.35.64.0/1812.35.64.1 to 12.35.127.25412.35.127.25516,382
14312.35.128.0/1812.35.128.1 to 12.35.191.25412.35.191.25516,382
14412.35.192.0/1812.35.192.1 to 12.35.255.25412.35.255.25516,382
14512.36.0.0/1812.36.0.1 to 12.36.63.25412.36.63.25516,382
14612.36.64.0/1812.36.64.1 to 12.36.127.25412.36.127.25516,382
14712.36.128.0/1812.36.128.1 to 12.36.191.25412.36.191.25516,382
14812.36.192.0/1812.36.192.1 to 12.36.255.25412.36.255.25516,382
14912.37.0.0/1812.37.0.1 to 12.37.63.25412.37.63.25516,382
15012.37.64.0/1812.37.64.1 to 12.37.127.25412.37.127.25516,382
15112.37.128.0/1812.37.128.1 to 12.37.191.25412.37.191.25516,382
15212.37.192.0/1812.37.192.1 to 12.37.255.25412.37.255.25516,382
15312.38.0.0/1812.38.0.1 to 12.38.63.25412.38.63.25516,382
15412.38.64.0/1812.38.64.1 to 12.38.127.25412.38.127.25516,382
15512.38.128.0/1812.38.128.1 to 12.38.191.25412.38.191.25516,382
15612.38.192.0/1812.38.192.1 to 12.38.255.25412.38.255.25516,382
15712.39.0.0/1812.39.0.1 to 12.39.63.25412.39.63.25516,382
15812.39.64.0/1812.39.64.1 to 12.39.127.25412.39.127.25516,382
15912.39.128.0/1812.39.128.1 to 12.39.191.25412.39.191.25516,382
16012.39.192.0/1812.39.192.1 to 12.39.255.25412.39.255.25516,382
16112.40.0.0/1812.40.0.1 to 12.40.63.25412.40.63.25516,382
16212.40.64.0/1812.40.64.1 to 12.40.127.25412.40.127.25516,382
16312.40.128.0/1812.40.128.1 to 12.40.191.25412.40.191.25516,382
16412.40.192.0/1812.40.192.1 to 12.40.255.25412.40.255.25516,382
16512.41.0.0/1812.41.0.1 to 12.41.63.25412.41.63.25516,382
16612.41.64.0/1812.41.64.1 to 12.41.127.25412.41.127.25516,382
16712.41.128.0/1812.41.128.1 to 12.41.191.25412.41.191.25516,382
16812.41.192.0/1812.41.192.1 to 12.41.255.25412.41.255.25516,382
16912.42.0.0/1812.42.0.1 to 12.42.63.25412.42.63.25516,382
17012.42.64.0/1812.42.64.1 to 12.42.127.25412.42.127.25516,382
17112.42.128.0/1812.42.128.1 to 12.42.191.25412.42.191.25516,382
17212.42.192.0/1812.42.192.1 to 12.42.255.25412.42.255.25516,382
17312.43.0.0/1812.43.0.1 to 12.43.63.25412.43.63.25516,382
17412.43.64.0/1812.43.64.1 to 12.43.127.25412.43.127.25516,382
17512.43.128.0/1812.43.128.1 to 12.43.191.25412.43.191.25516,382
17612.43.192.0/1812.43.192.1 to 12.43.255.25412.43.255.25516,382
17712.44.0.0/1812.44.0.1 to 12.44.63.25412.44.63.25516,382
17812.44.64.0/1812.44.64.1 to 12.44.127.25412.44.127.25516,382
17912.44.128.0/1812.44.128.1 to 12.44.191.25412.44.191.25516,382
18012.44.192.0/1812.44.192.1 to 12.44.255.25412.44.255.25516,382
18112.45.0.0/1812.45.0.1 to 12.45.63.25412.45.63.25516,382
18212.45.64.0/1812.45.64.1 to 12.45.127.25412.45.127.25516,382
18312.45.128.0/1812.45.128.1 to 12.45.191.25412.45.191.25516,382
18412.45.192.0/1812.45.192.1 to 12.45.255.25412.45.255.25516,382
18512.46.0.0/1812.46.0.1 to 12.46.63.25412.46.63.25516,382
18612.46.64.0/1812.46.64.1 to 12.46.127.25412.46.127.25516,382
18712.46.128.0/1812.46.128.1 to 12.46.191.25412.46.191.25516,382
18812.46.192.0/1812.46.192.1 to 12.46.255.25412.46.255.25516,382
18912.47.0.0/1812.47.0.1 to 12.47.63.25412.47.63.25516,382
19012.47.64.0/1812.47.64.1 to 12.47.127.25412.47.127.25516,382
19112.47.128.0/1812.47.128.1 to 12.47.191.25412.47.191.25516,382
19212.47.192.0/1812.47.192.1 to 12.47.255.25412.47.255.25516,382
19312.48.0.0/1812.48.0.1 to 12.48.63.25412.48.63.25516,382
19412.48.64.0/1812.48.64.1 to 12.48.127.25412.48.127.25516,382
19512.48.128.0/1812.48.128.1 to 12.48.191.25412.48.191.25516,382
19612.48.192.0/1812.48.192.1 to 12.48.255.25412.48.255.25516,382
19712.49.0.0/1812.49.0.1 to 12.49.63.25412.49.63.25516,382
19812.49.64.0/1812.49.64.1 to 12.49.127.25412.49.127.25516,382
19912.49.128.0/1812.49.128.1 to 12.49.191.25412.49.191.25516,382
20012.49.192.0/1812.49.192.1 to 12.49.255.25412.49.255.25516,382
20112.50.0.0/1812.50.0.1 to 12.50.63.25412.50.63.25516,382
20212.50.64.0/1812.50.64.1 to 12.50.127.25412.50.127.25516,382
20312.50.128.0/1812.50.128.1 to 12.50.191.25412.50.191.25516,382
20412.50.192.0/1812.50.192.1 to 12.50.255.25412.50.255.25516,382
20512.51.0.0/1812.51.0.1 to 12.51.63.25412.51.63.25516,382
20612.51.64.0/1812.51.64.1 to 12.51.127.25412.51.127.25516,382
20712.51.128.0/1812.51.128.1 to 12.51.191.25412.51.191.25516,382
20812.51.192.0/1812.51.192.1 to 12.51.255.25412.51.255.25516,382
20912.52.0.0/1812.52.0.1 to 12.52.63.25412.52.63.25516,382
21012.52.64.0/1812.52.64.1 to 12.52.127.25412.52.127.25516,382
21112.52.128.0/1812.52.128.1 to 12.52.191.25412.52.191.25516,382
21212.52.192.0/1812.52.192.1 to 12.52.255.25412.52.255.25516,382
21312.53.0.0/1812.53.0.1 to 12.53.63.25412.53.63.25516,382
21412.53.64.0/1812.53.64.1 to 12.53.127.25412.53.127.25516,382
21512.53.128.0/1812.53.128.1 to 12.53.191.25412.53.191.25516,382
21612.53.192.0/1812.53.192.1 to 12.53.255.25412.53.255.25516,382
21712.54.0.0/1812.54.0.1 to 12.54.63.25412.54.63.25516,382
21812.54.64.0/1812.54.64.1 to 12.54.127.25412.54.127.25516,382
21912.54.128.0/1812.54.128.1 to 12.54.191.25412.54.191.25516,382
22012.54.192.0/1812.54.192.1 to 12.54.255.25412.54.255.25516,382
22112.55.0.0/1812.55.0.1 to 12.55.63.25412.55.63.25516,382
22212.55.64.0/1812.55.64.1 to 12.55.127.25412.55.127.25516,382
22312.55.128.0/1812.55.128.1 to 12.55.191.25412.55.191.25516,382
22412.55.192.0/1812.55.192.1 to 12.55.255.25412.55.255.25516,382
22512.56.0.0/1812.56.0.1 to 12.56.63.25412.56.63.25516,382
22612.56.64.0/1812.56.64.1 to 12.56.127.25412.56.127.25516,382
22712.56.128.0/1812.56.128.1 to 12.56.191.25412.56.191.25516,382
22812.56.192.0/1812.56.192.1 to 12.56.255.25412.56.255.25516,382
22912.57.0.0/1812.57.0.1 to 12.57.63.25412.57.63.25516,382
23012.57.64.0/1812.57.64.1 to 12.57.127.25412.57.127.25516,382
23112.57.128.0/1812.57.128.1 to 12.57.191.25412.57.191.25516,382
23212.57.192.0/1812.57.192.1 to 12.57.255.25412.57.255.25516,382
23312.58.0.0/1812.58.0.1 to 12.58.63.25412.58.63.25516,382
23412.58.64.0/1812.58.64.1 to 12.58.127.25412.58.127.25516,382
23512.58.128.0/1812.58.128.1 to 12.58.191.25412.58.191.25516,382
23612.58.192.0/1812.58.192.1 to 12.58.255.25412.58.255.25516,382
23712.59.0.0/1812.59.0.1 to 12.59.63.25412.59.63.25516,382
23812.59.64.0/1812.59.64.1 to 12.59.127.25412.59.127.25516,382
23912.59.128.0/1812.59.128.1 to 12.59.191.25412.59.191.25516,382
24012.59.192.0/1812.59.192.1 to 12.59.255.25412.59.255.25516,382
24112.60.0.0/1812.60.0.1 to 12.60.63.25412.60.63.25516,382
24212.60.64.0/1812.60.64.1 to 12.60.127.25412.60.127.25516,382
24312.60.128.0/1812.60.128.1 to 12.60.191.25412.60.191.25516,382
24412.60.192.0/1812.60.192.1 to 12.60.255.25412.60.255.25516,382
24512.61.0.0/1812.61.0.1 to 12.61.63.25412.61.63.25516,382
24612.61.64.0/1812.61.64.1 to 12.61.127.25412.61.127.25516,382
24712.61.128.0/1812.61.128.1 to 12.61.191.25412.61.191.25516,382
24812.61.192.0/1812.61.192.1 to 12.61.255.25412.61.255.25516,382
24912.62.0.0/1812.62.0.1 to 12.62.63.25412.62.63.25516,382
25012.62.64.0/1812.62.64.1 to 12.62.127.25412.62.127.25516,382
25112.62.128.0/1812.62.128.1 to 12.62.191.25412.62.191.25516,382
25212.62.192.0/1812.62.192.1 to 12.62.255.25412.62.255.25516,382
25312.63.0.0/1812.63.0.1 to 12.63.63.25412.63.63.25516,382
25412.63.64.0/1812.63.64.1 to 12.63.127.25412.63.127.25516,382
25512.63.128.0/1812.63.128.1 to 12.63.191.25412.63.191.25516,382
25612.63.192.0/1812.63.192.1 to 12.63.255.25412.63.255.25516,382

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.