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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.

Network12.44.0.0/17
Usable hosts32,766
Subnet mask255.255.128.0
Addresses32,768
Network address
12.44.0.0
Broadcast address
12.44.127.255
First usable
12.44.0.1
Last usable
12.44.127.254
Usable hosts
32,766 (32,768 less the network and broadcast addresses)
Subnet mask
255.255.128.0
Wildcard mask
0.0.127.255 (Cisco ACLs, OSPF)
Prefix length
/17
Type
Public public
Old class
A (default /8)
As numbers
Hex 0C2C0000 · Integer 204210176 to 204242943
Reverse DNS zones
0.44.12.in-addr.arpa
1.44.12.in-addr.arpa
2.44.12.in-addr.arpa
3.44.12.in-addr.arpa
4.44.12.in-addr.arpa
5.44.12.in-addr.arpa
6.44.12.in-addr.arpa
7.44.12.in-addr.arpa
8.44.12.in-addr.arpa
9.44.12.in-addr.arpa
10.44.12.in-addr.arpa
11.44.12.in-addr.arpa
12.44.12.in-addr.arpa
13.44.12.in-addr.arpa
14.44.12.in-addr.arpa
15.44.12.in-addr.arpa
and 112 more
/17 is not on a 8-bit boundary, so it takes 128 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00001100.00101100.00000000.0000000012.44.0.0
Subnet mask11111111.11111111.10000000.00000000255.255.128.0
Network00001100.00101100.00000000.0000000012.44.0.0
Broadcast00001100.00101100.01111111.1111111112.44.127.255
Split into smaller subnets/27
/18 (2)/19 (4)/20 (8)/21 (16)/22 (32)/23 (64)/24 (128)/25 (256)/26 (512)/27 (1,024)/28 (2,048)/29 (4,096)

12.44.0.0/17 makes 1,024 subnets of /27; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
112.44.0.0/2712.44.0.1 to 12.44.0.3012.44.0.3130
212.44.0.32/2712.44.0.33 to 12.44.0.6212.44.0.6330
312.44.0.64/2712.44.0.65 to 12.44.0.9412.44.0.9530
412.44.0.96/2712.44.0.97 to 12.44.0.12612.44.0.12730
512.44.0.128/2712.44.0.129 to 12.44.0.15812.44.0.15930
612.44.0.160/2712.44.0.161 to 12.44.0.19012.44.0.19130
712.44.0.192/2712.44.0.193 to 12.44.0.22212.44.0.22330
812.44.0.224/2712.44.0.225 to 12.44.0.25412.44.0.25530
912.44.1.0/2712.44.1.1 to 12.44.1.3012.44.1.3130
1012.44.1.32/2712.44.1.33 to 12.44.1.6212.44.1.6330
1112.44.1.64/2712.44.1.65 to 12.44.1.9412.44.1.9530
1212.44.1.96/2712.44.1.97 to 12.44.1.12612.44.1.12730
1312.44.1.128/2712.44.1.129 to 12.44.1.15812.44.1.15930
1412.44.1.160/2712.44.1.161 to 12.44.1.19012.44.1.19130
1512.44.1.192/2712.44.1.193 to 12.44.1.22212.44.1.22330
1612.44.1.224/2712.44.1.225 to 12.44.1.25412.44.1.25530
1712.44.2.0/2712.44.2.1 to 12.44.2.3012.44.2.3130
1812.44.2.32/2712.44.2.33 to 12.44.2.6212.44.2.6330
1912.44.2.64/2712.44.2.65 to 12.44.2.9412.44.2.9530
2012.44.2.96/2712.44.2.97 to 12.44.2.12612.44.2.12730
2112.44.2.128/2712.44.2.129 to 12.44.2.15812.44.2.15930
2212.44.2.160/2712.44.2.161 to 12.44.2.19012.44.2.19130
2312.44.2.192/2712.44.2.193 to 12.44.2.22212.44.2.22330
2412.44.2.224/2712.44.2.225 to 12.44.2.25412.44.2.25530
2512.44.3.0/2712.44.3.1 to 12.44.3.3012.44.3.3130
2612.44.3.32/2712.44.3.33 to 12.44.3.6212.44.3.6330
2712.44.3.64/2712.44.3.65 to 12.44.3.9412.44.3.9530
2812.44.3.96/2712.44.3.97 to 12.44.3.12612.44.3.12730
2912.44.3.128/2712.44.3.129 to 12.44.3.15812.44.3.15930
3012.44.3.160/2712.44.3.161 to 12.44.3.19012.44.3.19130
3112.44.3.192/2712.44.3.193 to 12.44.3.22212.44.3.22330
3212.44.3.224/2712.44.3.225 to 12.44.3.25412.44.3.25530
3312.44.4.0/2712.44.4.1 to 12.44.4.3012.44.4.3130
3412.44.4.32/2712.44.4.33 to 12.44.4.6212.44.4.6330
3512.44.4.64/2712.44.4.65 to 12.44.4.9412.44.4.9530
3612.44.4.96/2712.44.4.97 to 12.44.4.12612.44.4.12730
3712.44.4.128/2712.44.4.129 to 12.44.4.15812.44.4.15930
3812.44.4.160/2712.44.4.161 to 12.44.4.19012.44.4.19130
3912.44.4.192/2712.44.4.193 to 12.44.4.22212.44.4.22330
4012.44.4.224/2712.44.4.225 to 12.44.4.25412.44.4.25530
4112.44.5.0/2712.44.5.1 to 12.44.5.3012.44.5.3130
4212.44.5.32/2712.44.5.33 to 12.44.5.6212.44.5.6330
4312.44.5.64/2712.44.5.65 to 12.44.5.9412.44.5.9530
4412.44.5.96/2712.44.5.97 to 12.44.5.12612.44.5.12730
4512.44.5.128/2712.44.5.129 to 12.44.5.15812.44.5.15930
4612.44.5.160/2712.44.5.161 to 12.44.5.19012.44.5.19130
4712.44.5.192/2712.44.5.193 to 12.44.5.22212.44.5.22330
4812.44.5.224/2712.44.5.225 to 12.44.5.25412.44.5.25530
4912.44.6.0/2712.44.6.1 to 12.44.6.3012.44.6.3130
5012.44.6.32/2712.44.6.33 to 12.44.6.6212.44.6.6330
5112.44.6.64/2712.44.6.65 to 12.44.6.9412.44.6.9530
5212.44.6.96/2712.44.6.97 to 12.44.6.12612.44.6.12730
5312.44.6.128/2712.44.6.129 to 12.44.6.15812.44.6.15930
5412.44.6.160/2712.44.6.161 to 12.44.6.19012.44.6.19130
5512.44.6.192/2712.44.6.193 to 12.44.6.22212.44.6.22330
5612.44.6.224/2712.44.6.225 to 12.44.6.25412.44.6.25530
5712.44.7.0/2712.44.7.1 to 12.44.7.3012.44.7.3130
5812.44.7.32/2712.44.7.33 to 12.44.7.6212.44.7.6330
5912.44.7.64/2712.44.7.65 to 12.44.7.9412.44.7.9530
6012.44.7.96/2712.44.7.97 to 12.44.7.12612.44.7.12730
6112.44.7.128/2712.44.7.129 to 12.44.7.15812.44.7.15930
6212.44.7.160/2712.44.7.161 to 12.44.7.19012.44.7.19130
6312.44.7.192/2712.44.7.193 to 12.44.7.22212.44.7.22330
6412.44.7.224/2712.44.7.225 to 12.44.7.25412.44.7.25530
6512.44.8.0/2712.44.8.1 to 12.44.8.3012.44.8.3130
6612.44.8.32/2712.44.8.33 to 12.44.8.6212.44.8.6330
6712.44.8.64/2712.44.8.65 to 12.44.8.9412.44.8.9530
6812.44.8.96/2712.44.8.97 to 12.44.8.12612.44.8.12730
6912.44.8.128/2712.44.8.129 to 12.44.8.15812.44.8.15930
7012.44.8.160/2712.44.8.161 to 12.44.8.19012.44.8.19130
7112.44.8.192/2712.44.8.193 to 12.44.8.22212.44.8.22330
7212.44.8.224/2712.44.8.225 to 12.44.8.25412.44.8.25530
7312.44.9.0/2712.44.9.1 to 12.44.9.3012.44.9.3130
7412.44.9.32/2712.44.9.33 to 12.44.9.6212.44.9.6330
7512.44.9.64/2712.44.9.65 to 12.44.9.9412.44.9.9530
7612.44.9.96/2712.44.9.97 to 12.44.9.12612.44.9.12730
7712.44.9.128/2712.44.9.129 to 12.44.9.15812.44.9.15930
7812.44.9.160/2712.44.9.161 to 12.44.9.19012.44.9.19130
7912.44.9.192/2712.44.9.193 to 12.44.9.22212.44.9.22330
8012.44.9.224/2712.44.9.225 to 12.44.9.25412.44.9.25530
8112.44.10.0/2712.44.10.1 to 12.44.10.3012.44.10.3130
8212.44.10.32/2712.44.10.33 to 12.44.10.6212.44.10.6330
8312.44.10.64/2712.44.10.65 to 12.44.10.9412.44.10.9530
8412.44.10.96/2712.44.10.97 to 12.44.10.12612.44.10.12730
8512.44.10.128/2712.44.10.129 to 12.44.10.15812.44.10.15930
8612.44.10.160/2712.44.10.161 to 12.44.10.19012.44.10.19130
8712.44.10.192/2712.44.10.193 to 12.44.10.22212.44.10.22330
8812.44.10.224/2712.44.10.225 to 12.44.10.25412.44.10.25530
8912.44.11.0/2712.44.11.1 to 12.44.11.3012.44.11.3130
9012.44.11.32/2712.44.11.33 to 12.44.11.6212.44.11.6330
9112.44.11.64/2712.44.11.65 to 12.44.11.9412.44.11.9530
9212.44.11.96/2712.44.11.97 to 12.44.11.12612.44.11.12730
9312.44.11.128/2712.44.11.129 to 12.44.11.15812.44.11.15930
9412.44.11.160/2712.44.11.161 to 12.44.11.19012.44.11.19130
9512.44.11.192/2712.44.11.193 to 12.44.11.22212.44.11.22330
9612.44.11.224/2712.44.11.225 to 12.44.11.25412.44.11.25530
9712.44.12.0/2712.44.12.1 to 12.44.12.3012.44.12.3130
9812.44.12.32/2712.44.12.33 to 12.44.12.6212.44.12.6330
9912.44.12.64/2712.44.12.65 to 12.44.12.9412.44.12.9530
10012.44.12.96/2712.44.12.97 to 12.44.12.12612.44.12.12730
10112.44.12.128/2712.44.12.129 to 12.44.12.15812.44.12.15930
10212.44.12.160/2712.44.12.161 to 12.44.12.19012.44.12.19130
10312.44.12.192/2712.44.12.193 to 12.44.12.22212.44.12.22330
10412.44.12.224/2712.44.12.225 to 12.44.12.25412.44.12.25530
10512.44.13.0/2712.44.13.1 to 12.44.13.3012.44.13.3130
10612.44.13.32/2712.44.13.33 to 12.44.13.6212.44.13.6330
10712.44.13.64/2712.44.13.65 to 12.44.13.9412.44.13.9530
10812.44.13.96/2712.44.13.97 to 12.44.13.12612.44.13.12730
10912.44.13.128/2712.44.13.129 to 12.44.13.15812.44.13.15930
11012.44.13.160/2712.44.13.161 to 12.44.13.19012.44.13.19130
11112.44.13.192/2712.44.13.193 to 12.44.13.22212.44.13.22330
11212.44.13.224/2712.44.13.225 to 12.44.13.25412.44.13.25530
11312.44.14.0/2712.44.14.1 to 12.44.14.3012.44.14.3130
11412.44.14.32/2712.44.14.33 to 12.44.14.6212.44.14.6330
11512.44.14.64/2712.44.14.65 to 12.44.14.9412.44.14.9530
11612.44.14.96/2712.44.14.97 to 12.44.14.12612.44.14.12730
11712.44.14.128/2712.44.14.129 to 12.44.14.15812.44.14.15930
11812.44.14.160/2712.44.14.161 to 12.44.14.19012.44.14.19130
11912.44.14.192/2712.44.14.193 to 12.44.14.22212.44.14.22330
12012.44.14.224/2712.44.14.225 to 12.44.14.25412.44.14.25530
12112.44.15.0/2712.44.15.1 to 12.44.15.3012.44.15.3130
12212.44.15.32/2712.44.15.33 to 12.44.15.6212.44.15.6330
12312.44.15.64/2712.44.15.65 to 12.44.15.9412.44.15.9530
12412.44.15.96/2712.44.15.97 to 12.44.15.12612.44.15.12730
12512.44.15.128/2712.44.15.129 to 12.44.15.15812.44.15.15930
12612.44.15.160/2712.44.15.161 to 12.44.15.19012.44.15.19130
12712.44.15.192/2712.44.15.193 to 12.44.15.22212.44.15.22330
12812.44.15.224/2712.44.15.225 to 12.44.15.25412.44.15.25530
12912.44.16.0/2712.44.16.1 to 12.44.16.3012.44.16.3130
13012.44.16.32/2712.44.16.33 to 12.44.16.6212.44.16.6330
13112.44.16.64/2712.44.16.65 to 12.44.16.9412.44.16.9530
13212.44.16.96/2712.44.16.97 to 12.44.16.12612.44.16.12730
13312.44.16.128/2712.44.16.129 to 12.44.16.15812.44.16.15930
13412.44.16.160/2712.44.16.161 to 12.44.16.19012.44.16.19130
13512.44.16.192/2712.44.16.193 to 12.44.16.22212.44.16.22330
13612.44.16.224/2712.44.16.225 to 12.44.16.25412.44.16.25530
13712.44.17.0/2712.44.17.1 to 12.44.17.3012.44.17.3130
13812.44.17.32/2712.44.17.33 to 12.44.17.6212.44.17.6330
13912.44.17.64/2712.44.17.65 to 12.44.17.9412.44.17.9530
14012.44.17.96/2712.44.17.97 to 12.44.17.12612.44.17.12730
14112.44.17.128/2712.44.17.129 to 12.44.17.15812.44.17.15930
14212.44.17.160/2712.44.17.161 to 12.44.17.19012.44.17.19130
14312.44.17.192/2712.44.17.193 to 12.44.17.22212.44.17.22330
14412.44.17.224/2712.44.17.225 to 12.44.17.25412.44.17.25530
14512.44.18.0/2712.44.18.1 to 12.44.18.3012.44.18.3130
14612.44.18.32/2712.44.18.33 to 12.44.18.6212.44.18.6330
14712.44.18.64/2712.44.18.65 to 12.44.18.9412.44.18.9530
14812.44.18.96/2712.44.18.97 to 12.44.18.12612.44.18.12730
14912.44.18.128/2712.44.18.129 to 12.44.18.15812.44.18.15930
15012.44.18.160/2712.44.18.161 to 12.44.18.19012.44.18.19130
15112.44.18.192/2712.44.18.193 to 12.44.18.22212.44.18.22330
15212.44.18.224/2712.44.18.225 to 12.44.18.25412.44.18.25530
15312.44.19.0/2712.44.19.1 to 12.44.19.3012.44.19.3130
15412.44.19.32/2712.44.19.33 to 12.44.19.6212.44.19.6330
15512.44.19.64/2712.44.19.65 to 12.44.19.9412.44.19.9530
15612.44.19.96/2712.44.19.97 to 12.44.19.12612.44.19.12730
15712.44.19.128/2712.44.19.129 to 12.44.19.15812.44.19.15930
15812.44.19.160/2712.44.19.161 to 12.44.19.19012.44.19.19130
15912.44.19.192/2712.44.19.193 to 12.44.19.22212.44.19.22330
16012.44.19.224/2712.44.19.225 to 12.44.19.25412.44.19.25530
16112.44.20.0/2712.44.20.1 to 12.44.20.3012.44.20.3130
16212.44.20.32/2712.44.20.33 to 12.44.20.6212.44.20.6330
16312.44.20.64/2712.44.20.65 to 12.44.20.9412.44.20.9530
16412.44.20.96/2712.44.20.97 to 12.44.20.12612.44.20.12730
16512.44.20.128/2712.44.20.129 to 12.44.20.15812.44.20.15930
16612.44.20.160/2712.44.20.161 to 12.44.20.19012.44.20.19130
16712.44.20.192/2712.44.20.193 to 12.44.20.22212.44.20.22330
16812.44.20.224/2712.44.20.225 to 12.44.20.25412.44.20.25530
16912.44.21.0/2712.44.21.1 to 12.44.21.3012.44.21.3130
17012.44.21.32/2712.44.21.33 to 12.44.21.6212.44.21.6330
17112.44.21.64/2712.44.21.65 to 12.44.21.9412.44.21.9530
17212.44.21.96/2712.44.21.97 to 12.44.21.12612.44.21.12730
17312.44.21.128/2712.44.21.129 to 12.44.21.15812.44.21.15930
17412.44.21.160/2712.44.21.161 to 12.44.21.19012.44.21.19130
17512.44.21.192/2712.44.21.193 to 12.44.21.22212.44.21.22330
17612.44.21.224/2712.44.21.225 to 12.44.21.25412.44.21.25530
17712.44.22.0/2712.44.22.1 to 12.44.22.3012.44.22.3130
17812.44.22.32/2712.44.22.33 to 12.44.22.6212.44.22.6330
17912.44.22.64/2712.44.22.65 to 12.44.22.9412.44.22.9530
18012.44.22.96/2712.44.22.97 to 12.44.22.12612.44.22.12730
18112.44.22.128/2712.44.22.129 to 12.44.22.15812.44.22.15930
18212.44.22.160/2712.44.22.161 to 12.44.22.19012.44.22.19130
18312.44.22.192/2712.44.22.193 to 12.44.22.22212.44.22.22330
18412.44.22.224/2712.44.22.225 to 12.44.22.25412.44.22.25530
18512.44.23.0/2712.44.23.1 to 12.44.23.3012.44.23.3130
18612.44.23.32/2712.44.23.33 to 12.44.23.6212.44.23.6330
18712.44.23.64/2712.44.23.65 to 12.44.23.9412.44.23.9530
18812.44.23.96/2712.44.23.97 to 12.44.23.12612.44.23.12730
18912.44.23.128/2712.44.23.129 to 12.44.23.15812.44.23.15930
19012.44.23.160/2712.44.23.161 to 12.44.23.19012.44.23.19130
19112.44.23.192/2712.44.23.193 to 12.44.23.22212.44.23.22330
19212.44.23.224/2712.44.23.225 to 12.44.23.25412.44.23.25530
19312.44.24.0/2712.44.24.1 to 12.44.24.3012.44.24.3130
19412.44.24.32/2712.44.24.33 to 12.44.24.6212.44.24.6330
19512.44.24.64/2712.44.24.65 to 12.44.24.9412.44.24.9530
19612.44.24.96/2712.44.24.97 to 12.44.24.12612.44.24.12730
19712.44.24.128/2712.44.24.129 to 12.44.24.15812.44.24.15930
19812.44.24.160/2712.44.24.161 to 12.44.24.19012.44.24.19130
19912.44.24.192/2712.44.24.193 to 12.44.24.22212.44.24.22330
20012.44.24.224/2712.44.24.225 to 12.44.24.25412.44.24.25530
20112.44.25.0/2712.44.25.1 to 12.44.25.3012.44.25.3130
20212.44.25.32/2712.44.25.33 to 12.44.25.6212.44.25.6330
20312.44.25.64/2712.44.25.65 to 12.44.25.9412.44.25.9530
20412.44.25.96/2712.44.25.97 to 12.44.25.12612.44.25.12730
20512.44.25.128/2712.44.25.129 to 12.44.25.15812.44.25.15930
20612.44.25.160/2712.44.25.161 to 12.44.25.19012.44.25.19130
20712.44.25.192/2712.44.25.193 to 12.44.25.22212.44.25.22330
20812.44.25.224/2712.44.25.225 to 12.44.25.25412.44.25.25530
20912.44.26.0/2712.44.26.1 to 12.44.26.3012.44.26.3130
21012.44.26.32/2712.44.26.33 to 12.44.26.6212.44.26.6330
21112.44.26.64/2712.44.26.65 to 12.44.26.9412.44.26.9530
21212.44.26.96/2712.44.26.97 to 12.44.26.12612.44.26.12730
21312.44.26.128/2712.44.26.129 to 12.44.26.15812.44.26.15930
21412.44.26.160/2712.44.26.161 to 12.44.26.19012.44.26.19130
21512.44.26.192/2712.44.26.193 to 12.44.26.22212.44.26.22330
21612.44.26.224/2712.44.26.225 to 12.44.26.25412.44.26.25530
21712.44.27.0/2712.44.27.1 to 12.44.27.3012.44.27.3130
21812.44.27.32/2712.44.27.33 to 12.44.27.6212.44.27.6330
21912.44.27.64/2712.44.27.65 to 12.44.27.9412.44.27.9530
22012.44.27.96/2712.44.27.97 to 12.44.27.12612.44.27.12730
22112.44.27.128/2712.44.27.129 to 12.44.27.15812.44.27.15930
22212.44.27.160/2712.44.27.161 to 12.44.27.19012.44.27.19130
22312.44.27.192/2712.44.27.193 to 12.44.27.22212.44.27.22330
22412.44.27.224/2712.44.27.225 to 12.44.27.25412.44.27.25530
22512.44.28.0/2712.44.28.1 to 12.44.28.3012.44.28.3130
22612.44.28.32/2712.44.28.33 to 12.44.28.6212.44.28.6330
22712.44.28.64/2712.44.28.65 to 12.44.28.9412.44.28.9530
22812.44.28.96/2712.44.28.97 to 12.44.28.12612.44.28.12730
22912.44.28.128/2712.44.28.129 to 12.44.28.15812.44.28.15930
23012.44.28.160/2712.44.28.161 to 12.44.28.19012.44.28.19130
23112.44.28.192/2712.44.28.193 to 12.44.28.22212.44.28.22330
23212.44.28.224/2712.44.28.225 to 12.44.28.25412.44.28.25530
23312.44.29.0/2712.44.29.1 to 12.44.29.3012.44.29.3130
23412.44.29.32/2712.44.29.33 to 12.44.29.6212.44.29.6330
23512.44.29.64/2712.44.29.65 to 12.44.29.9412.44.29.9530
23612.44.29.96/2712.44.29.97 to 12.44.29.12612.44.29.12730
23712.44.29.128/2712.44.29.129 to 12.44.29.15812.44.29.15930
23812.44.29.160/2712.44.29.161 to 12.44.29.19012.44.29.19130
23912.44.29.192/2712.44.29.193 to 12.44.29.22212.44.29.22330
24012.44.29.224/2712.44.29.225 to 12.44.29.25412.44.29.25530
24112.44.30.0/2712.44.30.1 to 12.44.30.3012.44.30.3130
24212.44.30.32/2712.44.30.33 to 12.44.30.6212.44.30.6330
24312.44.30.64/2712.44.30.65 to 12.44.30.9412.44.30.9530
24412.44.30.96/2712.44.30.97 to 12.44.30.12612.44.30.12730
24512.44.30.128/2712.44.30.129 to 12.44.30.15812.44.30.15930
24612.44.30.160/2712.44.30.161 to 12.44.30.19012.44.30.19130
24712.44.30.192/2712.44.30.193 to 12.44.30.22212.44.30.22330
24812.44.30.224/2712.44.30.225 to 12.44.30.25412.44.30.25530
24912.44.31.0/2712.44.31.1 to 12.44.31.3012.44.31.3130
25012.44.31.32/2712.44.31.33 to 12.44.31.6212.44.31.6330
25112.44.31.64/2712.44.31.65 to 12.44.31.9412.44.31.9530
25212.44.31.96/2712.44.31.97 to 12.44.31.12612.44.31.12730
25312.44.31.128/2712.44.31.129 to 12.44.31.15812.44.31.15930
25412.44.31.160/2712.44.31.161 to 12.44.31.19012.44.31.19130
25512.44.31.192/2712.44.31.193 to 12.44.31.22212.44.31.22330
25612.44.31.224/2712.44.31.225 to 12.44.31.25412.44.31.25530

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.