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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.

Network81.95.0.0/16
Usable hosts65,534
Subnet mask255.255.0.0
Addresses65,536
Network address
81.95.0.0
Broadcast address
81.95.255.255
First usable
81.95.0.1
Last usable
81.95.255.254
Usable hosts
65,534 (65,536 less the network and broadcast addresses)
Subnet mask
255.255.0.0
Wildcard mask
0.0.255.255 (Cisco ACLs, OSPF)
Prefix length
/16
Type
Public public
Old class
A (default /8)
As numbers
Hex 515F0000 · Integer 1365180416 to 1365245951
Reverse DNS zone
95.81.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01010001.01011111..00000000.0000000081.95.0.0
Subnet mask11111111.11111111..00000000.00000000255.255.0.0
Network01010001.01011111..00000000.0000000081.95.0.0
Broadcast01010001.01011111..11111111.1111111181.95.255.255
Split into smaller subnets/26
/17 (2)/18 (4)/19 (8)/20 (16)/21 (32)/22 (64)/23 (128)/24 (256)/25 (512)/26 (1,024)/27 (2,048)/28 (4,096)

81.95.0.0/16 makes 1,024 subnets of /26; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
181.95.0.0/2681.95.0.1 to 81.95.0.6281.95.0.6362
281.95.0.64/2681.95.0.65 to 81.95.0.12681.95.0.12762
381.95.0.128/2681.95.0.129 to 81.95.0.19081.95.0.19162
481.95.0.192/2681.95.0.193 to 81.95.0.25481.95.0.25562
581.95.1.0/2681.95.1.1 to 81.95.1.6281.95.1.6362
681.95.1.64/2681.95.1.65 to 81.95.1.12681.95.1.12762
781.95.1.128/2681.95.1.129 to 81.95.1.19081.95.1.19162
881.95.1.192/2681.95.1.193 to 81.95.1.25481.95.1.25562
981.95.2.0/2681.95.2.1 to 81.95.2.6281.95.2.6362
1081.95.2.64/2681.95.2.65 to 81.95.2.12681.95.2.12762
1181.95.2.128/2681.95.2.129 to 81.95.2.19081.95.2.19162
1281.95.2.192/2681.95.2.193 to 81.95.2.25481.95.2.25562
1381.95.3.0/2681.95.3.1 to 81.95.3.6281.95.3.6362
1481.95.3.64/2681.95.3.65 to 81.95.3.12681.95.3.12762
1581.95.3.128/2681.95.3.129 to 81.95.3.19081.95.3.19162
1681.95.3.192/2681.95.3.193 to 81.95.3.25481.95.3.25562
1781.95.4.0/2681.95.4.1 to 81.95.4.6281.95.4.6362
1881.95.4.64/2681.95.4.65 to 81.95.4.12681.95.4.12762
1981.95.4.128/2681.95.4.129 to 81.95.4.19081.95.4.19162
2081.95.4.192/2681.95.4.193 to 81.95.4.25481.95.4.25562
2181.95.5.0/2681.95.5.1 to 81.95.5.6281.95.5.6362
2281.95.5.64/2681.95.5.65 to 81.95.5.12681.95.5.12762
2381.95.5.128/2681.95.5.129 to 81.95.5.19081.95.5.19162
2481.95.5.192/2681.95.5.193 to 81.95.5.25481.95.5.25562
2581.95.6.0/2681.95.6.1 to 81.95.6.6281.95.6.6362
2681.95.6.64/2681.95.6.65 to 81.95.6.12681.95.6.12762
2781.95.6.128/2681.95.6.129 to 81.95.6.19081.95.6.19162
2881.95.6.192/2681.95.6.193 to 81.95.6.25481.95.6.25562
2981.95.7.0/2681.95.7.1 to 81.95.7.6281.95.7.6362
3081.95.7.64/2681.95.7.65 to 81.95.7.12681.95.7.12762
3181.95.7.128/2681.95.7.129 to 81.95.7.19081.95.7.19162
3281.95.7.192/2681.95.7.193 to 81.95.7.25481.95.7.25562
3381.95.8.0/2681.95.8.1 to 81.95.8.6281.95.8.6362
3481.95.8.64/2681.95.8.65 to 81.95.8.12681.95.8.12762
3581.95.8.128/2681.95.8.129 to 81.95.8.19081.95.8.19162
3681.95.8.192/2681.95.8.193 to 81.95.8.25481.95.8.25562
3781.95.9.0/2681.95.9.1 to 81.95.9.6281.95.9.6362
3881.95.9.64/2681.95.9.65 to 81.95.9.12681.95.9.12762
3981.95.9.128/2681.95.9.129 to 81.95.9.19081.95.9.19162
4081.95.9.192/2681.95.9.193 to 81.95.9.25481.95.9.25562
4181.95.10.0/2681.95.10.1 to 81.95.10.6281.95.10.6362
4281.95.10.64/2681.95.10.65 to 81.95.10.12681.95.10.12762
4381.95.10.128/2681.95.10.129 to 81.95.10.19081.95.10.19162
4481.95.10.192/2681.95.10.193 to 81.95.10.25481.95.10.25562
4581.95.11.0/2681.95.11.1 to 81.95.11.6281.95.11.6362
4681.95.11.64/2681.95.11.65 to 81.95.11.12681.95.11.12762
4781.95.11.128/2681.95.11.129 to 81.95.11.19081.95.11.19162
4881.95.11.192/2681.95.11.193 to 81.95.11.25481.95.11.25562
4981.95.12.0/2681.95.12.1 to 81.95.12.6281.95.12.6362
5081.95.12.64/2681.95.12.65 to 81.95.12.12681.95.12.12762
5181.95.12.128/2681.95.12.129 to 81.95.12.19081.95.12.19162
5281.95.12.192/2681.95.12.193 to 81.95.12.25481.95.12.25562
5381.95.13.0/2681.95.13.1 to 81.95.13.6281.95.13.6362
5481.95.13.64/2681.95.13.65 to 81.95.13.12681.95.13.12762
5581.95.13.128/2681.95.13.129 to 81.95.13.19081.95.13.19162
5681.95.13.192/2681.95.13.193 to 81.95.13.25481.95.13.25562
5781.95.14.0/2681.95.14.1 to 81.95.14.6281.95.14.6362
5881.95.14.64/2681.95.14.65 to 81.95.14.12681.95.14.12762
5981.95.14.128/2681.95.14.129 to 81.95.14.19081.95.14.19162
6081.95.14.192/2681.95.14.193 to 81.95.14.25481.95.14.25562
6181.95.15.0/2681.95.15.1 to 81.95.15.6281.95.15.6362
6281.95.15.64/2681.95.15.65 to 81.95.15.12681.95.15.12762
6381.95.15.128/2681.95.15.129 to 81.95.15.19081.95.15.19162
6481.95.15.192/2681.95.15.193 to 81.95.15.25481.95.15.25562
6581.95.16.0/2681.95.16.1 to 81.95.16.6281.95.16.6362
6681.95.16.64/2681.95.16.65 to 81.95.16.12681.95.16.12762
6781.95.16.128/2681.95.16.129 to 81.95.16.19081.95.16.19162
6881.95.16.192/2681.95.16.193 to 81.95.16.25481.95.16.25562
6981.95.17.0/2681.95.17.1 to 81.95.17.6281.95.17.6362
7081.95.17.64/2681.95.17.65 to 81.95.17.12681.95.17.12762
7181.95.17.128/2681.95.17.129 to 81.95.17.19081.95.17.19162
7281.95.17.192/2681.95.17.193 to 81.95.17.25481.95.17.25562
7381.95.18.0/2681.95.18.1 to 81.95.18.6281.95.18.6362
7481.95.18.64/2681.95.18.65 to 81.95.18.12681.95.18.12762
7581.95.18.128/2681.95.18.129 to 81.95.18.19081.95.18.19162
7681.95.18.192/2681.95.18.193 to 81.95.18.25481.95.18.25562
7781.95.19.0/2681.95.19.1 to 81.95.19.6281.95.19.6362
7881.95.19.64/2681.95.19.65 to 81.95.19.12681.95.19.12762
7981.95.19.128/2681.95.19.129 to 81.95.19.19081.95.19.19162
8081.95.19.192/2681.95.19.193 to 81.95.19.25481.95.19.25562
8181.95.20.0/2681.95.20.1 to 81.95.20.6281.95.20.6362
8281.95.20.64/2681.95.20.65 to 81.95.20.12681.95.20.12762
8381.95.20.128/2681.95.20.129 to 81.95.20.19081.95.20.19162
8481.95.20.192/2681.95.20.193 to 81.95.20.25481.95.20.25562
8581.95.21.0/2681.95.21.1 to 81.95.21.6281.95.21.6362
8681.95.21.64/2681.95.21.65 to 81.95.21.12681.95.21.12762
8781.95.21.128/2681.95.21.129 to 81.95.21.19081.95.21.19162
8881.95.21.192/2681.95.21.193 to 81.95.21.25481.95.21.25562
8981.95.22.0/2681.95.22.1 to 81.95.22.6281.95.22.6362
9081.95.22.64/2681.95.22.65 to 81.95.22.12681.95.22.12762
9181.95.22.128/2681.95.22.129 to 81.95.22.19081.95.22.19162
9281.95.22.192/2681.95.22.193 to 81.95.22.25481.95.22.25562
9381.95.23.0/2681.95.23.1 to 81.95.23.6281.95.23.6362
9481.95.23.64/2681.95.23.65 to 81.95.23.12681.95.23.12762
9581.95.23.128/2681.95.23.129 to 81.95.23.19081.95.23.19162
9681.95.23.192/2681.95.23.193 to 81.95.23.25481.95.23.25562
9781.95.24.0/2681.95.24.1 to 81.95.24.6281.95.24.6362
9881.95.24.64/2681.95.24.65 to 81.95.24.12681.95.24.12762
9981.95.24.128/2681.95.24.129 to 81.95.24.19081.95.24.19162
10081.95.24.192/2681.95.24.193 to 81.95.24.25481.95.24.25562
10181.95.25.0/2681.95.25.1 to 81.95.25.6281.95.25.6362
10281.95.25.64/2681.95.25.65 to 81.95.25.12681.95.25.12762
10381.95.25.128/2681.95.25.129 to 81.95.25.19081.95.25.19162
10481.95.25.192/2681.95.25.193 to 81.95.25.25481.95.25.25562
10581.95.26.0/2681.95.26.1 to 81.95.26.6281.95.26.6362
10681.95.26.64/2681.95.26.65 to 81.95.26.12681.95.26.12762
10781.95.26.128/2681.95.26.129 to 81.95.26.19081.95.26.19162
10881.95.26.192/2681.95.26.193 to 81.95.26.25481.95.26.25562
10981.95.27.0/2681.95.27.1 to 81.95.27.6281.95.27.6362
11081.95.27.64/2681.95.27.65 to 81.95.27.12681.95.27.12762
11181.95.27.128/2681.95.27.129 to 81.95.27.19081.95.27.19162
11281.95.27.192/2681.95.27.193 to 81.95.27.25481.95.27.25562
11381.95.28.0/2681.95.28.1 to 81.95.28.6281.95.28.6362
11481.95.28.64/2681.95.28.65 to 81.95.28.12681.95.28.12762
11581.95.28.128/2681.95.28.129 to 81.95.28.19081.95.28.19162
11681.95.28.192/2681.95.28.193 to 81.95.28.25481.95.28.25562
11781.95.29.0/2681.95.29.1 to 81.95.29.6281.95.29.6362
11881.95.29.64/2681.95.29.65 to 81.95.29.12681.95.29.12762
11981.95.29.128/2681.95.29.129 to 81.95.29.19081.95.29.19162
12081.95.29.192/2681.95.29.193 to 81.95.29.25481.95.29.25562
12181.95.30.0/2681.95.30.1 to 81.95.30.6281.95.30.6362
12281.95.30.64/2681.95.30.65 to 81.95.30.12681.95.30.12762
12381.95.30.128/2681.95.30.129 to 81.95.30.19081.95.30.19162
12481.95.30.192/2681.95.30.193 to 81.95.30.25481.95.30.25562
12581.95.31.0/2681.95.31.1 to 81.95.31.6281.95.31.6362
12681.95.31.64/2681.95.31.65 to 81.95.31.12681.95.31.12762
12781.95.31.128/2681.95.31.129 to 81.95.31.19081.95.31.19162
12881.95.31.192/2681.95.31.193 to 81.95.31.25481.95.31.25562
12981.95.32.0/2681.95.32.1 to 81.95.32.6281.95.32.6362
13081.95.32.64/2681.95.32.65 to 81.95.32.12681.95.32.12762
13181.95.32.128/2681.95.32.129 to 81.95.32.19081.95.32.19162
13281.95.32.192/2681.95.32.193 to 81.95.32.25481.95.32.25562
13381.95.33.0/2681.95.33.1 to 81.95.33.6281.95.33.6362
13481.95.33.64/2681.95.33.65 to 81.95.33.12681.95.33.12762
13581.95.33.128/2681.95.33.129 to 81.95.33.19081.95.33.19162
13681.95.33.192/2681.95.33.193 to 81.95.33.25481.95.33.25562
13781.95.34.0/2681.95.34.1 to 81.95.34.6281.95.34.6362
13881.95.34.64/2681.95.34.65 to 81.95.34.12681.95.34.12762
13981.95.34.128/2681.95.34.129 to 81.95.34.19081.95.34.19162
14081.95.34.192/2681.95.34.193 to 81.95.34.25481.95.34.25562
14181.95.35.0/2681.95.35.1 to 81.95.35.6281.95.35.6362
14281.95.35.64/2681.95.35.65 to 81.95.35.12681.95.35.12762
14381.95.35.128/2681.95.35.129 to 81.95.35.19081.95.35.19162
14481.95.35.192/2681.95.35.193 to 81.95.35.25481.95.35.25562
14581.95.36.0/2681.95.36.1 to 81.95.36.6281.95.36.6362
14681.95.36.64/2681.95.36.65 to 81.95.36.12681.95.36.12762
14781.95.36.128/2681.95.36.129 to 81.95.36.19081.95.36.19162
14881.95.36.192/2681.95.36.193 to 81.95.36.25481.95.36.25562
14981.95.37.0/2681.95.37.1 to 81.95.37.6281.95.37.6362
15081.95.37.64/2681.95.37.65 to 81.95.37.12681.95.37.12762
15181.95.37.128/2681.95.37.129 to 81.95.37.19081.95.37.19162
15281.95.37.192/2681.95.37.193 to 81.95.37.25481.95.37.25562
15381.95.38.0/2681.95.38.1 to 81.95.38.6281.95.38.6362
15481.95.38.64/2681.95.38.65 to 81.95.38.12681.95.38.12762
15581.95.38.128/2681.95.38.129 to 81.95.38.19081.95.38.19162
15681.95.38.192/2681.95.38.193 to 81.95.38.25481.95.38.25562
15781.95.39.0/2681.95.39.1 to 81.95.39.6281.95.39.6362
15881.95.39.64/2681.95.39.65 to 81.95.39.12681.95.39.12762
15981.95.39.128/2681.95.39.129 to 81.95.39.19081.95.39.19162
16081.95.39.192/2681.95.39.193 to 81.95.39.25481.95.39.25562
16181.95.40.0/2681.95.40.1 to 81.95.40.6281.95.40.6362
16281.95.40.64/2681.95.40.65 to 81.95.40.12681.95.40.12762
16381.95.40.128/2681.95.40.129 to 81.95.40.19081.95.40.19162
16481.95.40.192/2681.95.40.193 to 81.95.40.25481.95.40.25562
16581.95.41.0/2681.95.41.1 to 81.95.41.6281.95.41.6362
16681.95.41.64/2681.95.41.65 to 81.95.41.12681.95.41.12762
16781.95.41.128/2681.95.41.129 to 81.95.41.19081.95.41.19162
16881.95.41.192/2681.95.41.193 to 81.95.41.25481.95.41.25562
16981.95.42.0/2681.95.42.1 to 81.95.42.6281.95.42.6362
17081.95.42.64/2681.95.42.65 to 81.95.42.12681.95.42.12762
17181.95.42.128/2681.95.42.129 to 81.95.42.19081.95.42.19162
17281.95.42.192/2681.95.42.193 to 81.95.42.25481.95.42.25562
17381.95.43.0/2681.95.43.1 to 81.95.43.6281.95.43.6362
17481.95.43.64/2681.95.43.65 to 81.95.43.12681.95.43.12762
17581.95.43.128/2681.95.43.129 to 81.95.43.19081.95.43.19162
17681.95.43.192/2681.95.43.193 to 81.95.43.25481.95.43.25562
17781.95.44.0/2681.95.44.1 to 81.95.44.6281.95.44.6362
17881.95.44.64/2681.95.44.65 to 81.95.44.12681.95.44.12762
17981.95.44.128/2681.95.44.129 to 81.95.44.19081.95.44.19162
18081.95.44.192/2681.95.44.193 to 81.95.44.25481.95.44.25562
18181.95.45.0/2681.95.45.1 to 81.95.45.6281.95.45.6362
18281.95.45.64/2681.95.45.65 to 81.95.45.12681.95.45.12762
18381.95.45.128/2681.95.45.129 to 81.95.45.19081.95.45.19162
18481.95.45.192/2681.95.45.193 to 81.95.45.25481.95.45.25562
18581.95.46.0/2681.95.46.1 to 81.95.46.6281.95.46.6362
18681.95.46.64/2681.95.46.65 to 81.95.46.12681.95.46.12762
18781.95.46.128/2681.95.46.129 to 81.95.46.19081.95.46.19162
18881.95.46.192/2681.95.46.193 to 81.95.46.25481.95.46.25562
18981.95.47.0/2681.95.47.1 to 81.95.47.6281.95.47.6362
19081.95.47.64/2681.95.47.65 to 81.95.47.12681.95.47.12762
19181.95.47.128/2681.95.47.129 to 81.95.47.19081.95.47.19162
19281.95.47.192/2681.95.47.193 to 81.95.47.25481.95.47.25562
19381.95.48.0/2681.95.48.1 to 81.95.48.6281.95.48.6362
19481.95.48.64/2681.95.48.65 to 81.95.48.12681.95.48.12762
19581.95.48.128/2681.95.48.129 to 81.95.48.19081.95.48.19162
19681.95.48.192/2681.95.48.193 to 81.95.48.25481.95.48.25562
19781.95.49.0/2681.95.49.1 to 81.95.49.6281.95.49.6362
19881.95.49.64/2681.95.49.65 to 81.95.49.12681.95.49.12762
19981.95.49.128/2681.95.49.129 to 81.95.49.19081.95.49.19162
20081.95.49.192/2681.95.49.193 to 81.95.49.25481.95.49.25562
20181.95.50.0/2681.95.50.1 to 81.95.50.6281.95.50.6362
20281.95.50.64/2681.95.50.65 to 81.95.50.12681.95.50.12762
20381.95.50.128/2681.95.50.129 to 81.95.50.19081.95.50.19162
20481.95.50.192/2681.95.50.193 to 81.95.50.25481.95.50.25562
20581.95.51.0/2681.95.51.1 to 81.95.51.6281.95.51.6362
20681.95.51.64/2681.95.51.65 to 81.95.51.12681.95.51.12762
20781.95.51.128/2681.95.51.129 to 81.95.51.19081.95.51.19162
20881.95.51.192/2681.95.51.193 to 81.95.51.25481.95.51.25562
20981.95.52.0/2681.95.52.1 to 81.95.52.6281.95.52.6362
21081.95.52.64/2681.95.52.65 to 81.95.52.12681.95.52.12762
21181.95.52.128/2681.95.52.129 to 81.95.52.19081.95.52.19162
21281.95.52.192/2681.95.52.193 to 81.95.52.25481.95.52.25562
21381.95.53.0/2681.95.53.1 to 81.95.53.6281.95.53.6362
21481.95.53.64/2681.95.53.65 to 81.95.53.12681.95.53.12762
21581.95.53.128/2681.95.53.129 to 81.95.53.19081.95.53.19162
21681.95.53.192/2681.95.53.193 to 81.95.53.25481.95.53.25562
21781.95.54.0/2681.95.54.1 to 81.95.54.6281.95.54.6362
21881.95.54.64/2681.95.54.65 to 81.95.54.12681.95.54.12762
21981.95.54.128/2681.95.54.129 to 81.95.54.19081.95.54.19162
22081.95.54.192/2681.95.54.193 to 81.95.54.25481.95.54.25562
22181.95.55.0/2681.95.55.1 to 81.95.55.6281.95.55.6362
22281.95.55.64/2681.95.55.65 to 81.95.55.12681.95.55.12762
22381.95.55.128/2681.95.55.129 to 81.95.55.19081.95.55.19162
22481.95.55.192/2681.95.55.193 to 81.95.55.25481.95.55.25562
22581.95.56.0/2681.95.56.1 to 81.95.56.6281.95.56.6362
22681.95.56.64/2681.95.56.65 to 81.95.56.12681.95.56.12762
22781.95.56.128/2681.95.56.129 to 81.95.56.19081.95.56.19162
22881.95.56.192/2681.95.56.193 to 81.95.56.25481.95.56.25562
22981.95.57.0/2681.95.57.1 to 81.95.57.6281.95.57.6362
23081.95.57.64/2681.95.57.65 to 81.95.57.12681.95.57.12762
23181.95.57.128/2681.95.57.129 to 81.95.57.19081.95.57.19162
23281.95.57.192/2681.95.57.193 to 81.95.57.25481.95.57.25562
23381.95.58.0/2681.95.58.1 to 81.95.58.6281.95.58.6362
23481.95.58.64/2681.95.58.65 to 81.95.58.12681.95.58.12762
23581.95.58.128/2681.95.58.129 to 81.95.58.19081.95.58.19162
23681.95.58.192/2681.95.58.193 to 81.95.58.25481.95.58.25562
23781.95.59.0/2681.95.59.1 to 81.95.59.6281.95.59.6362
23881.95.59.64/2681.95.59.65 to 81.95.59.12681.95.59.12762
23981.95.59.128/2681.95.59.129 to 81.95.59.19081.95.59.19162
24081.95.59.192/2681.95.59.193 to 81.95.59.25481.95.59.25562
24181.95.60.0/2681.95.60.1 to 81.95.60.6281.95.60.6362
24281.95.60.64/2681.95.60.65 to 81.95.60.12681.95.60.12762
24381.95.60.128/2681.95.60.129 to 81.95.60.19081.95.60.19162
24481.95.60.192/2681.95.60.193 to 81.95.60.25481.95.60.25562
24581.95.61.0/2681.95.61.1 to 81.95.61.6281.95.61.6362
24681.95.61.64/2681.95.61.65 to 81.95.61.12681.95.61.12762
24781.95.61.128/2681.95.61.129 to 81.95.61.19081.95.61.19162
24881.95.61.192/2681.95.61.193 to 81.95.61.25481.95.61.25562
24981.95.62.0/2681.95.62.1 to 81.95.62.6281.95.62.6362
25081.95.62.64/2681.95.62.65 to 81.95.62.12681.95.62.12762
25181.95.62.128/2681.95.62.129 to 81.95.62.19081.95.62.19162
25281.95.62.192/2681.95.62.193 to 81.95.62.25481.95.62.25562
25381.95.63.0/2681.95.63.1 to 81.95.63.6281.95.63.6362
25481.95.63.64/2681.95.63.65 to 81.95.63.12681.95.63.12762
25581.95.63.128/2681.95.63.129 to 81.95.63.19081.95.63.19162
25681.95.63.192/2681.95.63.193 to 81.95.63.25481.95.63.25562

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.