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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.

Network44.78.0.0/17
Usable hosts32,766
Subnet mask255.255.128.0
Addresses32,768
Network address
44.78.0.0
Broadcast address
44.78.127.255
First usable
44.78.0.1
Last usable
44.78.127.254
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 2C4E0000 · Integer 743309312 to 743342079
Reverse DNS zones
0.78.44.in-addr.arpa
1.78.44.in-addr.arpa
2.78.44.in-addr.arpa
3.78.44.in-addr.arpa
4.78.44.in-addr.arpa
5.78.44.in-addr.arpa
6.78.44.in-addr.arpa
7.78.44.in-addr.arpa
8.78.44.in-addr.arpa
9.78.44.in-addr.arpa
10.78.44.in-addr.arpa
11.78.44.in-addr.arpa
12.78.44.in-addr.arpa
13.78.44.in-addr.arpa
14.78.44.in-addr.arpa
15.78.44.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
Address00101100.01001110.00000000.0000000044.78.0.0
Subnet mask11111111.11111111.10000000.00000000255.255.128.0
Network00101100.01001110.00000000.0000000044.78.0.0
Broadcast00101100.01001110.01111111.1111111144.78.127.255
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)

44.78.0.0/17 makes 1,024 subnets of /27; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
144.78.0.0/2744.78.0.1 to 44.78.0.3044.78.0.3130
244.78.0.32/2744.78.0.33 to 44.78.0.6244.78.0.6330
344.78.0.64/2744.78.0.65 to 44.78.0.9444.78.0.9530
444.78.0.96/2744.78.0.97 to 44.78.0.12644.78.0.12730
544.78.0.128/2744.78.0.129 to 44.78.0.15844.78.0.15930
644.78.0.160/2744.78.0.161 to 44.78.0.19044.78.0.19130
744.78.0.192/2744.78.0.193 to 44.78.0.22244.78.0.22330
844.78.0.224/2744.78.0.225 to 44.78.0.25444.78.0.25530
944.78.1.0/2744.78.1.1 to 44.78.1.3044.78.1.3130
1044.78.1.32/2744.78.1.33 to 44.78.1.6244.78.1.6330
1144.78.1.64/2744.78.1.65 to 44.78.1.9444.78.1.9530
1244.78.1.96/2744.78.1.97 to 44.78.1.12644.78.1.12730
1344.78.1.128/2744.78.1.129 to 44.78.1.15844.78.1.15930
1444.78.1.160/2744.78.1.161 to 44.78.1.19044.78.1.19130
1544.78.1.192/2744.78.1.193 to 44.78.1.22244.78.1.22330
1644.78.1.224/2744.78.1.225 to 44.78.1.25444.78.1.25530
1744.78.2.0/2744.78.2.1 to 44.78.2.3044.78.2.3130
1844.78.2.32/2744.78.2.33 to 44.78.2.6244.78.2.6330
1944.78.2.64/2744.78.2.65 to 44.78.2.9444.78.2.9530
2044.78.2.96/2744.78.2.97 to 44.78.2.12644.78.2.12730
2144.78.2.128/2744.78.2.129 to 44.78.2.15844.78.2.15930
2244.78.2.160/2744.78.2.161 to 44.78.2.19044.78.2.19130
2344.78.2.192/2744.78.2.193 to 44.78.2.22244.78.2.22330
2444.78.2.224/2744.78.2.225 to 44.78.2.25444.78.2.25530
2544.78.3.0/2744.78.3.1 to 44.78.3.3044.78.3.3130
2644.78.3.32/2744.78.3.33 to 44.78.3.6244.78.3.6330
2744.78.3.64/2744.78.3.65 to 44.78.3.9444.78.3.9530
2844.78.3.96/2744.78.3.97 to 44.78.3.12644.78.3.12730
2944.78.3.128/2744.78.3.129 to 44.78.3.15844.78.3.15930
3044.78.3.160/2744.78.3.161 to 44.78.3.19044.78.3.19130
3144.78.3.192/2744.78.3.193 to 44.78.3.22244.78.3.22330
3244.78.3.224/2744.78.3.225 to 44.78.3.25444.78.3.25530
3344.78.4.0/2744.78.4.1 to 44.78.4.3044.78.4.3130
3444.78.4.32/2744.78.4.33 to 44.78.4.6244.78.4.6330
3544.78.4.64/2744.78.4.65 to 44.78.4.9444.78.4.9530
3644.78.4.96/2744.78.4.97 to 44.78.4.12644.78.4.12730
3744.78.4.128/2744.78.4.129 to 44.78.4.15844.78.4.15930
3844.78.4.160/2744.78.4.161 to 44.78.4.19044.78.4.19130
3944.78.4.192/2744.78.4.193 to 44.78.4.22244.78.4.22330
4044.78.4.224/2744.78.4.225 to 44.78.4.25444.78.4.25530
4144.78.5.0/2744.78.5.1 to 44.78.5.3044.78.5.3130
4244.78.5.32/2744.78.5.33 to 44.78.5.6244.78.5.6330
4344.78.5.64/2744.78.5.65 to 44.78.5.9444.78.5.9530
4444.78.5.96/2744.78.5.97 to 44.78.5.12644.78.5.12730
4544.78.5.128/2744.78.5.129 to 44.78.5.15844.78.5.15930
4644.78.5.160/2744.78.5.161 to 44.78.5.19044.78.5.19130
4744.78.5.192/2744.78.5.193 to 44.78.5.22244.78.5.22330
4844.78.5.224/2744.78.5.225 to 44.78.5.25444.78.5.25530
4944.78.6.0/2744.78.6.1 to 44.78.6.3044.78.6.3130
5044.78.6.32/2744.78.6.33 to 44.78.6.6244.78.6.6330
5144.78.6.64/2744.78.6.65 to 44.78.6.9444.78.6.9530
5244.78.6.96/2744.78.6.97 to 44.78.6.12644.78.6.12730
5344.78.6.128/2744.78.6.129 to 44.78.6.15844.78.6.15930
5444.78.6.160/2744.78.6.161 to 44.78.6.19044.78.6.19130
5544.78.6.192/2744.78.6.193 to 44.78.6.22244.78.6.22330
5644.78.6.224/2744.78.6.225 to 44.78.6.25444.78.6.25530
5744.78.7.0/2744.78.7.1 to 44.78.7.3044.78.7.3130
5844.78.7.32/2744.78.7.33 to 44.78.7.6244.78.7.6330
5944.78.7.64/2744.78.7.65 to 44.78.7.9444.78.7.9530
6044.78.7.96/2744.78.7.97 to 44.78.7.12644.78.7.12730
6144.78.7.128/2744.78.7.129 to 44.78.7.15844.78.7.15930
6244.78.7.160/2744.78.7.161 to 44.78.7.19044.78.7.19130
6344.78.7.192/2744.78.7.193 to 44.78.7.22244.78.7.22330
6444.78.7.224/2744.78.7.225 to 44.78.7.25444.78.7.25530
6544.78.8.0/2744.78.8.1 to 44.78.8.3044.78.8.3130
6644.78.8.32/2744.78.8.33 to 44.78.8.6244.78.8.6330
6744.78.8.64/2744.78.8.65 to 44.78.8.9444.78.8.9530
6844.78.8.96/2744.78.8.97 to 44.78.8.12644.78.8.12730
6944.78.8.128/2744.78.8.129 to 44.78.8.15844.78.8.15930
7044.78.8.160/2744.78.8.161 to 44.78.8.19044.78.8.19130
7144.78.8.192/2744.78.8.193 to 44.78.8.22244.78.8.22330
7244.78.8.224/2744.78.8.225 to 44.78.8.25444.78.8.25530
7344.78.9.0/2744.78.9.1 to 44.78.9.3044.78.9.3130
7444.78.9.32/2744.78.9.33 to 44.78.9.6244.78.9.6330
7544.78.9.64/2744.78.9.65 to 44.78.9.9444.78.9.9530
7644.78.9.96/2744.78.9.97 to 44.78.9.12644.78.9.12730
7744.78.9.128/2744.78.9.129 to 44.78.9.15844.78.9.15930
7844.78.9.160/2744.78.9.161 to 44.78.9.19044.78.9.19130
7944.78.9.192/2744.78.9.193 to 44.78.9.22244.78.9.22330
8044.78.9.224/2744.78.9.225 to 44.78.9.25444.78.9.25530
8144.78.10.0/2744.78.10.1 to 44.78.10.3044.78.10.3130
8244.78.10.32/2744.78.10.33 to 44.78.10.6244.78.10.6330
8344.78.10.64/2744.78.10.65 to 44.78.10.9444.78.10.9530
8444.78.10.96/2744.78.10.97 to 44.78.10.12644.78.10.12730
8544.78.10.128/2744.78.10.129 to 44.78.10.15844.78.10.15930
8644.78.10.160/2744.78.10.161 to 44.78.10.19044.78.10.19130
8744.78.10.192/2744.78.10.193 to 44.78.10.22244.78.10.22330
8844.78.10.224/2744.78.10.225 to 44.78.10.25444.78.10.25530
8944.78.11.0/2744.78.11.1 to 44.78.11.3044.78.11.3130
9044.78.11.32/2744.78.11.33 to 44.78.11.6244.78.11.6330
9144.78.11.64/2744.78.11.65 to 44.78.11.9444.78.11.9530
9244.78.11.96/2744.78.11.97 to 44.78.11.12644.78.11.12730
9344.78.11.128/2744.78.11.129 to 44.78.11.15844.78.11.15930
9444.78.11.160/2744.78.11.161 to 44.78.11.19044.78.11.19130
9544.78.11.192/2744.78.11.193 to 44.78.11.22244.78.11.22330
9644.78.11.224/2744.78.11.225 to 44.78.11.25444.78.11.25530
9744.78.12.0/2744.78.12.1 to 44.78.12.3044.78.12.3130
9844.78.12.32/2744.78.12.33 to 44.78.12.6244.78.12.6330
9944.78.12.64/2744.78.12.65 to 44.78.12.9444.78.12.9530
10044.78.12.96/2744.78.12.97 to 44.78.12.12644.78.12.12730
10144.78.12.128/2744.78.12.129 to 44.78.12.15844.78.12.15930
10244.78.12.160/2744.78.12.161 to 44.78.12.19044.78.12.19130
10344.78.12.192/2744.78.12.193 to 44.78.12.22244.78.12.22330
10444.78.12.224/2744.78.12.225 to 44.78.12.25444.78.12.25530
10544.78.13.0/2744.78.13.1 to 44.78.13.3044.78.13.3130
10644.78.13.32/2744.78.13.33 to 44.78.13.6244.78.13.6330
10744.78.13.64/2744.78.13.65 to 44.78.13.9444.78.13.9530
10844.78.13.96/2744.78.13.97 to 44.78.13.12644.78.13.12730
10944.78.13.128/2744.78.13.129 to 44.78.13.15844.78.13.15930
11044.78.13.160/2744.78.13.161 to 44.78.13.19044.78.13.19130
11144.78.13.192/2744.78.13.193 to 44.78.13.22244.78.13.22330
11244.78.13.224/2744.78.13.225 to 44.78.13.25444.78.13.25530
11344.78.14.0/2744.78.14.1 to 44.78.14.3044.78.14.3130
11444.78.14.32/2744.78.14.33 to 44.78.14.6244.78.14.6330
11544.78.14.64/2744.78.14.65 to 44.78.14.9444.78.14.9530
11644.78.14.96/2744.78.14.97 to 44.78.14.12644.78.14.12730
11744.78.14.128/2744.78.14.129 to 44.78.14.15844.78.14.15930
11844.78.14.160/2744.78.14.161 to 44.78.14.19044.78.14.19130
11944.78.14.192/2744.78.14.193 to 44.78.14.22244.78.14.22330
12044.78.14.224/2744.78.14.225 to 44.78.14.25444.78.14.25530
12144.78.15.0/2744.78.15.1 to 44.78.15.3044.78.15.3130
12244.78.15.32/2744.78.15.33 to 44.78.15.6244.78.15.6330
12344.78.15.64/2744.78.15.65 to 44.78.15.9444.78.15.9530
12444.78.15.96/2744.78.15.97 to 44.78.15.12644.78.15.12730
12544.78.15.128/2744.78.15.129 to 44.78.15.15844.78.15.15930
12644.78.15.160/2744.78.15.161 to 44.78.15.19044.78.15.19130
12744.78.15.192/2744.78.15.193 to 44.78.15.22244.78.15.22330
12844.78.15.224/2744.78.15.225 to 44.78.15.25444.78.15.25530
12944.78.16.0/2744.78.16.1 to 44.78.16.3044.78.16.3130
13044.78.16.32/2744.78.16.33 to 44.78.16.6244.78.16.6330
13144.78.16.64/2744.78.16.65 to 44.78.16.9444.78.16.9530
13244.78.16.96/2744.78.16.97 to 44.78.16.12644.78.16.12730
13344.78.16.128/2744.78.16.129 to 44.78.16.15844.78.16.15930
13444.78.16.160/2744.78.16.161 to 44.78.16.19044.78.16.19130
13544.78.16.192/2744.78.16.193 to 44.78.16.22244.78.16.22330
13644.78.16.224/2744.78.16.225 to 44.78.16.25444.78.16.25530
13744.78.17.0/2744.78.17.1 to 44.78.17.3044.78.17.3130
13844.78.17.32/2744.78.17.33 to 44.78.17.6244.78.17.6330
13944.78.17.64/2744.78.17.65 to 44.78.17.9444.78.17.9530
14044.78.17.96/2744.78.17.97 to 44.78.17.12644.78.17.12730
14144.78.17.128/2744.78.17.129 to 44.78.17.15844.78.17.15930
14244.78.17.160/2744.78.17.161 to 44.78.17.19044.78.17.19130
14344.78.17.192/2744.78.17.193 to 44.78.17.22244.78.17.22330
14444.78.17.224/2744.78.17.225 to 44.78.17.25444.78.17.25530
14544.78.18.0/2744.78.18.1 to 44.78.18.3044.78.18.3130
14644.78.18.32/2744.78.18.33 to 44.78.18.6244.78.18.6330
14744.78.18.64/2744.78.18.65 to 44.78.18.9444.78.18.9530
14844.78.18.96/2744.78.18.97 to 44.78.18.12644.78.18.12730
14944.78.18.128/2744.78.18.129 to 44.78.18.15844.78.18.15930
15044.78.18.160/2744.78.18.161 to 44.78.18.19044.78.18.19130
15144.78.18.192/2744.78.18.193 to 44.78.18.22244.78.18.22330
15244.78.18.224/2744.78.18.225 to 44.78.18.25444.78.18.25530
15344.78.19.0/2744.78.19.1 to 44.78.19.3044.78.19.3130
15444.78.19.32/2744.78.19.33 to 44.78.19.6244.78.19.6330
15544.78.19.64/2744.78.19.65 to 44.78.19.9444.78.19.9530
15644.78.19.96/2744.78.19.97 to 44.78.19.12644.78.19.12730
15744.78.19.128/2744.78.19.129 to 44.78.19.15844.78.19.15930
15844.78.19.160/2744.78.19.161 to 44.78.19.19044.78.19.19130
15944.78.19.192/2744.78.19.193 to 44.78.19.22244.78.19.22330
16044.78.19.224/2744.78.19.225 to 44.78.19.25444.78.19.25530
16144.78.20.0/2744.78.20.1 to 44.78.20.3044.78.20.3130
16244.78.20.32/2744.78.20.33 to 44.78.20.6244.78.20.6330
16344.78.20.64/2744.78.20.65 to 44.78.20.9444.78.20.9530
16444.78.20.96/2744.78.20.97 to 44.78.20.12644.78.20.12730
16544.78.20.128/2744.78.20.129 to 44.78.20.15844.78.20.15930
16644.78.20.160/2744.78.20.161 to 44.78.20.19044.78.20.19130
16744.78.20.192/2744.78.20.193 to 44.78.20.22244.78.20.22330
16844.78.20.224/2744.78.20.225 to 44.78.20.25444.78.20.25530
16944.78.21.0/2744.78.21.1 to 44.78.21.3044.78.21.3130
17044.78.21.32/2744.78.21.33 to 44.78.21.6244.78.21.6330
17144.78.21.64/2744.78.21.65 to 44.78.21.9444.78.21.9530
17244.78.21.96/2744.78.21.97 to 44.78.21.12644.78.21.12730
17344.78.21.128/2744.78.21.129 to 44.78.21.15844.78.21.15930
17444.78.21.160/2744.78.21.161 to 44.78.21.19044.78.21.19130
17544.78.21.192/2744.78.21.193 to 44.78.21.22244.78.21.22330
17644.78.21.224/2744.78.21.225 to 44.78.21.25444.78.21.25530
17744.78.22.0/2744.78.22.1 to 44.78.22.3044.78.22.3130
17844.78.22.32/2744.78.22.33 to 44.78.22.6244.78.22.6330
17944.78.22.64/2744.78.22.65 to 44.78.22.9444.78.22.9530
18044.78.22.96/2744.78.22.97 to 44.78.22.12644.78.22.12730
18144.78.22.128/2744.78.22.129 to 44.78.22.15844.78.22.15930
18244.78.22.160/2744.78.22.161 to 44.78.22.19044.78.22.19130
18344.78.22.192/2744.78.22.193 to 44.78.22.22244.78.22.22330
18444.78.22.224/2744.78.22.225 to 44.78.22.25444.78.22.25530
18544.78.23.0/2744.78.23.1 to 44.78.23.3044.78.23.3130
18644.78.23.32/2744.78.23.33 to 44.78.23.6244.78.23.6330
18744.78.23.64/2744.78.23.65 to 44.78.23.9444.78.23.9530
18844.78.23.96/2744.78.23.97 to 44.78.23.12644.78.23.12730
18944.78.23.128/2744.78.23.129 to 44.78.23.15844.78.23.15930
19044.78.23.160/2744.78.23.161 to 44.78.23.19044.78.23.19130
19144.78.23.192/2744.78.23.193 to 44.78.23.22244.78.23.22330
19244.78.23.224/2744.78.23.225 to 44.78.23.25444.78.23.25530
19344.78.24.0/2744.78.24.1 to 44.78.24.3044.78.24.3130
19444.78.24.32/2744.78.24.33 to 44.78.24.6244.78.24.6330
19544.78.24.64/2744.78.24.65 to 44.78.24.9444.78.24.9530
19644.78.24.96/2744.78.24.97 to 44.78.24.12644.78.24.12730
19744.78.24.128/2744.78.24.129 to 44.78.24.15844.78.24.15930
19844.78.24.160/2744.78.24.161 to 44.78.24.19044.78.24.19130
19944.78.24.192/2744.78.24.193 to 44.78.24.22244.78.24.22330
20044.78.24.224/2744.78.24.225 to 44.78.24.25444.78.24.25530
20144.78.25.0/2744.78.25.1 to 44.78.25.3044.78.25.3130
20244.78.25.32/2744.78.25.33 to 44.78.25.6244.78.25.6330
20344.78.25.64/2744.78.25.65 to 44.78.25.9444.78.25.9530
20444.78.25.96/2744.78.25.97 to 44.78.25.12644.78.25.12730
20544.78.25.128/2744.78.25.129 to 44.78.25.15844.78.25.15930
20644.78.25.160/2744.78.25.161 to 44.78.25.19044.78.25.19130
20744.78.25.192/2744.78.25.193 to 44.78.25.22244.78.25.22330
20844.78.25.224/2744.78.25.225 to 44.78.25.25444.78.25.25530
20944.78.26.0/2744.78.26.1 to 44.78.26.3044.78.26.3130
21044.78.26.32/2744.78.26.33 to 44.78.26.6244.78.26.6330
21144.78.26.64/2744.78.26.65 to 44.78.26.9444.78.26.9530
21244.78.26.96/2744.78.26.97 to 44.78.26.12644.78.26.12730
21344.78.26.128/2744.78.26.129 to 44.78.26.15844.78.26.15930
21444.78.26.160/2744.78.26.161 to 44.78.26.19044.78.26.19130
21544.78.26.192/2744.78.26.193 to 44.78.26.22244.78.26.22330
21644.78.26.224/2744.78.26.225 to 44.78.26.25444.78.26.25530
21744.78.27.0/2744.78.27.1 to 44.78.27.3044.78.27.3130
21844.78.27.32/2744.78.27.33 to 44.78.27.6244.78.27.6330
21944.78.27.64/2744.78.27.65 to 44.78.27.9444.78.27.9530
22044.78.27.96/2744.78.27.97 to 44.78.27.12644.78.27.12730
22144.78.27.128/2744.78.27.129 to 44.78.27.15844.78.27.15930
22244.78.27.160/2744.78.27.161 to 44.78.27.19044.78.27.19130
22344.78.27.192/2744.78.27.193 to 44.78.27.22244.78.27.22330
22444.78.27.224/2744.78.27.225 to 44.78.27.25444.78.27.25530
22544.78.28.0/2744.78.28.1 to 44.78.28.3044.78.28.3130
22644.78.28.32/2744.78.28.33 to 44.78.28.6244.78.28.6330
22744.78.28.64/2744.78.28.65 to 44.78.28.9444.78.28.9530
22844.78.28.96/2744.78.28.97 to 44.78.28.12644.78.28.12730
22944.78.28.128/2744.78.28.129 to 44.78.28.15844.78.28.15930
23044.78.28.160/2744.78.28.161 to 44.78.28.19044.78.28.19130
23144.78.28.192/2744.78.28.193 to 44.78.28.22244.78.28.22330
23244.78.28.224/2744.78.28.225 to 44.78.28.25444.78.28.25530
23344.78.29.0/2744.78.29.1 to 44.78.29.3044.78.29.3130
23444.78.29.32/2744.78.29.33 to 44.78.29.6244.78.29.6330
23544.78.29.64/2744.78.29.65 to 44.78.29.9444.78.29.9530
23644.78.29.96/2744.78.29.97 to 44.78.29.12644.78.29.12730
23744.78.29.128/2744.78.29.129 to 44.78.29.15844.78.29.15930
23844.78.29.160/2744.78.29.161 to 44.78.29.19044.78.29.19130
23944.78.29.192/2744.78.29.193 to 44.78.29.22244.78.29.22330
24044.78.29.224/2744.78.29.225 to 44.78.29.25444.78.29.25530
24144.78.30.0/2744.78.30.1 to 44.78.30.3044.78.30.3130
24244.78.30.32/2744.78.30.33 to 44.78.30.6244.78.30.6330
24344.78.30.64/2744.78.30.65 to 44.78.30.9444.78.30.9530
24444.78.30.96/2744.78.30.97 to 44.78.30.12644.78.30.12730
24544.78.30.128/2744.78.30.129 to 44.78.30.15844.78.30.15930
24644.78.30.160/2744.78.30.161 to 44.78.30.19044.78.30.19130
24744.78.30.192/2744.78.30.193 to 44.78.30.22244.78.30.22330
24844.78.30.224/2744.78.30.225 to 44.78.30.25444.78.30.25530
24944.78.31.0/2744.78.31.1 to 44.78.31.3044.78.31.3130
25044.78.31.32/2744.78.31.33 to 44.78.31.6244.78.31.6330
25144.78.31.64/2744.78.31.65 to 44.78.31.9444.78.31.9530
25244.78.31.96/2744.78.31.97 to 44.78.31.12644.78.31.12730
25344.78.31.128/2744.78.31.129 to 44.78.31.15844.78.31.15930
25444.78.31.160/2744.78.31.161 to 44.78.31.19044.78.31.19130
25544.78.31.192/2744.78.31.193 to 44.78.31.22244.78.31.22330
25644.78.31.224/2744.78.31.225 to 44.78.31.25444.78.31.25530

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.