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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.

Network26.3.48.0/20
Usable hosts4,094
Subnet mask255.255.240.0
Addresses4,096
Network address
26.3.48.0
Broadcast address
26.3.63.255
First usable
26.3.48.1
Last usable
26.3.63.254
Usable hosts
4,094 (4,096 less the network and broadcast addresses)
Subnet mask
255.255.240.0
Wildcard mask
0.0.15.255 (Cisco ACLs, OSPF)
Prefix length
/20
Type
Public public
Old class
A (default /8)
As numbers
Hex 1A033000 · Integer 436416512 to 436420607
Reverse DNS zones
48.3.26.in-addr.arpa
49.3.26.in-addr.arpa
50.3.26.in-addr.arpa
51.3.26.in-addr.arpa
52.3.26.in-addr.arpa
53.3.26.in-addr.arpa
54.3.26.in-addr.arpa
55.3.26.in-addr.arpa
56.3.26.in-addr.arpa
57.3.26.in-addr.arpa
58.3.26.in-addr.arpa
59.3.26.in-addr.arpa
60.3.26.in-addr.arpa
61.3.26.in-addr.arpa
62.3.26.in-addr.arpa
63.3.26.in-addr.arpa
/20 is not on a 8-bit boundary, so it takes 16 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00011010.00000011.00110000.0000000026.3.48.0
Subnet mask11111111.11111111.11110000.00000000255.255.240.0
Network00011010.00000011.00110000.0000000026.3.48.0
Broadcast00011010.00000011.00111111.1111111126.3.63.255
Split into smaller subnets/30
/21 (2)/22 (4)/23 (8)/24 (16)/25 (32)/26 (64)/27 (128)/28 (256)/29 (512)/30 (1,024)/31 (2,048)/32 (4,096)

26.3.48.0/20 makes 1,024 subnets of /30; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
126.3.48.0/3026.3.48.1 to 26.3.48.226.3.48.32
226.3.48.4/3026.3.48.5 to 26.3.48.626.3.48.72
326.3.48.8/3026.3.48.9 to 26.3.48.1026.3.48.112
426.3.48.12/3026.3.48.13 to 26.3.48.1426.3.48.152
526.3.48.16/3026.3.48.17 to 26.3.48.1826.3.48.192
626.3.48.20/3026.3.48.21 to 26.3.48.2226.3.48.232
726.3.48.24/3026.3.48.25 to 26.3.48.2626.3.48.272
826.3.48.28/3026.3.48.29 to 26.3.48.3026.3.48.312
926.3.48.32/3026.3.48.33 to 26.3.48.3426.3.48.352
1026.3.48.36/3026.3.48.37 to 26.3.48.3826.3.48.392
1126.3.48.40/3026.3.48.41 to 26.3.48.4226.3.48.432
1226.3.48.44/3026.3.48.45 to 26.3.48.4626.3.48.472
1326.3.48.48/3026.3.48.49 to 26.3.48.5026.3.48.512
1426.3.48.52/3026.3.48.53 to 26.3.48.5426.3.48.552
1526.3.48.56/3026.3.48.57 to 26.3.48.5826.3.48.592
1626.3.48.60/3026.3.48.61 to 26.3.48.6226.3.48.632
1726.3.48.64/3026.3.48.65 to 26.3.48.6626.3.48.672
1826.3.48.68/3026.3.48.69 to 26.3.48.7026.3.48.712
1926.3.48.72/3026.3.48.73 to 26.3.48.7426.3.48.752
2026.3.48.76/3026.3.48.77 to 26.3.48.7826.3.48.792
2126.3.48.80/3026.3.48.81 to 26.3.48.8226.3.48.832
2226.3.48.84/3026.3.48.85 to 26.3.48.8626.3.48.872
2326.3.48.88/3026.3.48.89 to 26.3.48.9026.3.48.912
2426.3.48.92/3026.3.48.93 to 26.3.48.9426.3.48.952
2526.3.48.96/3026.3.48.97 to 26.3.48.9826.3.48.992
2626.3.48.100/3026.3.48.101 to 26.3.48.10226.3.48.1032
2726.3.48.104/3026.3.48.105 to 26.3.48.10626.3.48.1072
2826.3.48.108/3026.3.48.109 to 26.3.48.11026.3.48.1112
2926.3.48.112/3026.3.48.113 to 26.3.48.11426.3.48.1152
3026.3.48.116/3026.3.48.117 to 26.3.48.11826.3.48.1192
3126.3.48.120/3026.3.48.121 to 26.3.48.12226.3.48.1232
3226.3.48.124/3026.3.48.125 to 26.3.48.12626.3.48.1272
3326.3.48.128/3026.3.48.129 to 26.3.48.13026.3.48.1312
3426.3.48.132/3026.3.48.133 to 26.3.48.13426.3.48.1352
3526.3.48.136/3026.3.48.137 to 26.3.48.13826.3.48.1392
3626.3.48.140/3026.3.48.141 to 26.3.48.14226.3.48.1432
3726.3.48.144/3026.3.48.145 to 26.3.48.14626.3.48.1472
3826.3.48.148/3026.3.48.149 to 26.3.48.15026.3.48.1512
3926.3.48.152/3026.3.48.153 to 26.3.48.15426.3.48.1552
4026.3.48.156/3026.3.48.157 to 26.3.48.15826.3.48.1592
4126.3.48.160/3026.3.48.161 to 26.3.48.16226.3.48.1632
4226.3.48.164/3026.3.48.165 to 26.3.48.16626.3.48.1672
4326.3.48.168/3026.3.48.169 to 26.3.48.17026.3.48.1712
4426.3.48.172/3026.3.48.173 to 26.3.48.17426.3.48.1752
4526.3.48.176/3026.3.48.177 to 26.3.48.17826.3.48.1792
4626.3.48.180/3026.3.48.181 to 26.3.48.18226.3.48.1832
4726.3.48.184/3026.3.48.185 to 26.3.48.18626.3.48.1872
4826.3.48.188/3026.3.48.189 to 26.3.48.19026.3.48.1912
4926.3.48.192/3026.3.48.193 to 26.3.48.19426.3.48.1952
5026.3.48.196/3026.3.48.197 to 26.3.48.19826.3.48.1992
5126.3.48.200/3026.3.48.201 to 26.3.48.20226.3.48.2032
5226.3.48.204/3026.3.48.205 to 26.3.48.20626.3.48.2072
5326.3.48.208/3026.3.48.209 to 26.3.48.21026.3.48.2112
5426.3.48.212/3026.3.48.213 to 26.3.48.21426.3.48.2152
5526.3.48.216/3026.3.48.217 to 26.3.48.21826.3.48.2192
5626.3.48.220/3026.3.48.221 to 26.3.48.22226.3.48.2232
5726.3.48.224/3026.3.48.225 to 26.3.48.22626.3.48.2272
5826.3.48.228/3026.3.48.229 to 26.3.48.23026.3.48.2312
5926.3.48.232/3026.3.48.233 to 26.3.48.23426.3.48.2352
6026.3.48.236/3026.3.48.237 to 26.3.48.23826.3.48.2392
6126.3.48.240/3026.3.48.241 to 26.3.48.24226.3.48.2432
6226.3.48.244/3026.3.48.245 to 26.3.48.24626.3.48.2472
6326.3.48.248/3026.3.48.249 to 26.3.48.25026.3.48.2512
6426.3.48.252/3026.3.48.253 to 26.3.48.25426.3.48.2552
6526.3.49.0/3026.3.49.1 to 26.3.49.226.3.49.32
6626.3.49.4/3026.3.49.5 to 26.3.49.626.3.49.72
6726.3.49.8/3026.3.49.9 to 26.3.49.1026.3.49.112
6826.3.49.12/3026.3.49.13 to 26.3.49.1426.3.49.152
6926.3.49.16/3026.3.49.17 to 26.3.49.1826.3.49.192
7026.3.49.20/3026.3.49.21 to 26.3.49.2226.3.49.232
7126.3.49.24/3026.3.49.25 to 26.3.49.2626.3.49.272
7226.3.49.28/3026.3.49.29 to 26.3.49.3026.3.49.312
7326.3.49.32/3026.3.49.33 to 26.3.49.3426.3.49.352
7426.3.49.36/3026.3.49.37 to 26.3.49.3826.3.49.392
7526.3.49.40/3026.3.49.41 to 26.3.49.4226.3.49.432
7626.3.49.44/3026.3.49.45 to 26.3.49.4626.3.49.472
7726.3.49.48/3026.3.49.49 to 26.3.49.5026.3.49.512
7826.3.49.52/3026.3.49.53 to 26.3.49.5426.3.49.552
7926.3.49.56/3026.3.49.57 to 26.3.49.5826.3.49.592
8026.3.49.60/3026.3.49.61 to 26.3.49.6226.3.49.632
8126.3.49.64/3026.3.49.65 to 26.3.49.6626.3.49.672
8226.3.49.68/3026.3.49.69 to 26.3.49.7026.3.49.712
8326.3.49.72/3026.3.49.73 to 26.3.49.7426.3.49.752
8426.3.49.76/3026.3.49.77 to 26.3.49.7826.3.49.792
8526.3.49.80/3026.3.49.81 to 26.3.49.8226.3.49.832
8626.3.49.84/3026.3.49.85 to 26.3.49.8626.3.49.872
8726.3.49.88/3026.3.49.89 to 26.3.49.9026.3.49.912
8826.3.49.92/3026.3.49.93 to 26.3.49.9426.3.49.952
8926.3.49.96/3026.3.49.97 to 26.3.49.9826.3.49.992
9026.3.49.100/3026.3.49.101 to 26.3.49.10226.3.49.1032
9126.3.49.104/3026.3.49.105 to 26.3.49.10626.3.49.1072
9226.3.49.108/3026.3.49.109 to 26.3.49.11026.3.49.1112
9326.3.49.112/3026.3.49.113 to 26.3.49.11426.3.49.1152
9426.3.49.116/3026.3.49.117 to 26.3.49.11826.3.49.1192
9526.3.49.120/3026.3.49.121 to 26.3.49.12226.3.49.1232
9626.3.49.124/3026.3.49.125 to 26.3.49.12626.3.49.1272
9726.3.49.128/3026.3.49.129 to 26.3.49.13026.3.49.1312
9826.3.49.132/3026.3.49.133 to 26.3.49.13426.3.49.1352
9926.3.49.136/3026.3.49.137 to 26.3.49.13826.3.49.1392
10026.3.49.140/3026.3.49.141 to 26.3.49.14226.3.49.1432
10126.3.49.144/3026.3.49.145 to 26.3.49.14626.3.49.1472
10226.3.49.148/3026.3.49.149 to 26.3.49.15026.3.49.1512
10326.3.49.152/3026.3.49.153 to 26.3.49.15426.3.49.1552
10426.3.49.156/3026.3.49.157 to 26.3.49.15826.3.49.1592
10526.3.49.160/3026.3.49.161 to 26.3.49.16226.3.49.1632
10626.3.49.164/3026.3.49.165 to 26.3.49.16626.3.49.1672
10726.3.49.168/3026.3.49.169 to 26.3.49.17026.3.49.1712
10826.3.49.172/3026.3.49.173 to 26.3.49.17426.3.49.1752
10926.3.49.176/3026.3.49.177 to 26.3.49.17826.3.49.1792
11026.3.49.180/3026.3.49.181 to 26.3.49.18226.3.49.1832
11126.3.49.184/3026.3.49.185 to 26.3.49.18626.3.49.1872
11226.3.49.188/3026.3.49.189 to 26.3.49.19026.3.49.1912
11326.3.49.192/3026.3.49.193 to 26.3.49.19426.3.49.1952
11426.3.49.196/3026.3.49.197 to 26.3.49.19826.3.49.1992
11526.3.49.200/3026.3.49.201 to 26.3.49.20226.3.49.2032
11626.3.49.204/3026.3.49.205 to 26.3.49.20626.3.49.2072
11726.3.49.208/3026.3.49.209 to 26.3.49.21026.3.49.2112
11826.3.49.212/3026.3.49.213 to 26.3.49.21426.3.49.2152
11926.3.49.216/3026.3.49.217 to 26.3.49.21826.3.49.2192
12026.3.49.220/3026.3.49.221 to 26.3.49.22226.3.49.2232
12126.3.49.224/3026.3.49.225 to 26.3.49.22626.3.49.2272
12226.3.49.228/3026.3.49.229 to 26.3.49.23026.3.49.2312
12326.3.49.232/3026.3.49.233 to 26.3.49.23426.3.49.2352
12426.3.49.236/3026.3.49.237 to 26.3.49.23826.3.49.2392
12526.3.49.240/3026.3.49.241 to 26.3.49.24226.3.49.2432
12626.3.49.244/3026.3.49.245 to 26.3.49.24626.3.49.2472
12726.3.49.248/3026.3.49.249 to 26.3.49.25026.3.49.2512
12826.3.49.252/3026.3.49.253 to 26.3.49.25426.3.49.2552
12926.3.50.0/3026.3.50.1 to 26.3.50.226.3.50.32
13026.3.50.4/3026.3.50.5 to 26.3.50.626.3.50.72
13126.3.50.8/3026.3.50.9 to 26.3.50.1026.3.50.112
13226.3.50.12/3026.3.50.13 to 26.3.50.1426.3.50.152
13326.3.50.16/3026.3.50.17 to 26.3.50.1826.3.50.192
13426.3.50.20/3026.3.50.21 to 26.3.50.2226.3.50.232
13526.3.50.24/3026.3.50.25 to 26.3.50.2626.3.50.272
13626.3.50.28/3026.3.50.29 to 26.3.50.3026.3.50.312
13726.3.50.32/3026.3.50.33 to 26.3.50.3426.3.50.352
13826.3.50.36/3026.3.50.37 to 26.3.50.3826.3.50.392
13926.3.50.40/3026.3.50.41 to 26.3.50.4226.3.50.432
14026.3.50.44/3026.3.50.45 to 26.3.50.4626.3.50.472
14126.3.50.48/3026.3.50.49 to 26.3.50.5026.3.50.512
14226.3.50.52/3026.3.50.53 to 26.3.50.5426.3.50.552
14326.3.50.56/3026.3.50.57 to 26.3.50.5826.3.50.592
14426.3.50.60/3026.3.50.61 to 26.3.50.6226.3.50.632
14526.3.50.64/3026.3.50.65 to 26.3.50.6626.3.50.672
14626.3.50.68/3026.3.50.69 to 26.3.50.7026.3.50.712
14726.3.50.72/3026.3.50.73 to 26.3.50.7426.3.50.752
14826.3.50.76/3026.3.50.77 to 26.3.50.7826.3.50.792
14926.3.50.80/3026.3.50.81 to 26.3.50.8226.3.50.832
15026.3.50.84/3026.3.50.85 to 26.3.50.8626.3.50.872
15126.3.50.88/3026.3.50.89 to 26.3.50.9026.3.50.912
15226.3.50.92/3026.3.50.93 to 26.3.50.9426.3.50.952
15326.3.50.96/3026.3.50.97 to 26.3.50.9826.3.50.992
15426.3.50.100/3026.3.50.101 to 26.3.50.10226.3.50.1032
15526.3.50.104/3026.3.50.105 to 26.3.50.10626.3.50.1072
15626.3.50.108/3026.3.50.109 to 26.3.50.11026.3.50.1112
15726.3.50.112/3026.3.50.113 to 26.3.50.11426.3.50.1152
15826.3.50.116/3026.3.50.117 to 26.3.50.11826.3.50.1192
15926.3.50.120/3026.3.50.121 to 26.3.50.12226.3.50.1232
16026.3.50.124/3026.3.50.125 to 26.3.50.12626.3.50.1272
16126.3.50.128/3026.3.50.129 to 26.3.50.13026.3.50.1312
16226.3.50.132/3026.3.50.133 to 26.3.50.13426.3.50.1352
16326.3.50.136/3026.3.50.137 to 26.3.50.13826.3.50.1392
16426.3.50.140/3026.3.50.141 to 26.3.50.14226.3.50.1432
16526.3.50.144/3026.3.50.145 to 26.3.50.14626.3.50.1472
16626.3.50.148/3026.3.50.149 to 26.3.50.15026.3.50.1512
16726.3.50.152/3026.3.50.153 to 26.3.50.15426.3.50.1552
16826.3.50.156/3026.3.50.157 to 26.3.50.15826.3.50.1592
16926.3.50.160/3026.3.50.161 to 26.3.50.16226.3.50.1632
17026.3.50.164/3026.3.50.165 to 26.3.50.16626.3.50.1672
17126.3.50.168/3026.3.50.169 to 26.3.50.17026.3.50.1712
17226.3.50.172/3026.3.50.173 to 26.3.50.17426.3.50.1752
17326.3.50.176/3026.3.50.177 to 26.3.50.17826.3.50.1792
17426.3.50.180/3026.3.50.181 to 26.3.50.18226.3.50.1832
17526.3.50.184/3026.3.50.185 to 26.3.50.18626.3.50.1872
17626.3.50.188/3026.3.50.189 to 26.3.50.19026.3.50.1912
17726.3.50.192/3026.3.50.193 to 26.3.50.19426.3.50.1952
17826.3.50.196/3026.3.50.197 to 26.3.50.19826.3.50.1992
17926.3.50.200/3026.3.50.201 to 26.3.50.20226.3.50.2032
18026.3.50.204/3026.3.50.205 to 26.3.50.20626.3.50.2072
18126.3.50.208/3026.3.50.209 to 26.3.50.21026.3.50.2112
18226.3.50.212/3026.3.50.213 to 26.3.50.21426.3.50.2152
18326.3.50.216/3026.3.50.217 to 26.3.50.21826.3.50.2192
18426.3.50.220/3026.3.50.221 to 26.3.50.22226.3.50.2232
18526.3.50.224/3026.3.50.225 to 26.3.50.22626.3.50.2272
18626.3.50.228/3026.3.50.229 to 26.3.50.23026.3.50.2312
18726.3.50.232/3026.3.50.233 to 26.3.50.23426.3.50.2352
18826.3.50.236/3026.3.50.237 to 26.3.50.23826.3.50.2392
18926.3.50.240/3026.3.50.241 to 26.3.50.24226.3.50.2432
19026.3.50.244/3026.3.50.245 to 26.3.50.24626.3.50.2472
19126.3.50.248/3026.3.50.249 to 26.3.50.25026.3.50.2512
19226.3.50.252/3026.3.50.253 to 26.3.50.25426.3.50.2552
19326.3.51.0/3026.3.51.1 to 26.3.51.226.3.51.32
19426.3.51.4/3026.3.51.5 to 26.3.51.626.3.51.72
19526.3.51.8/3026.3.51.9 to 26.3.51.1026.3.51.112
19626.3.51.12/3026.3.51.13 to 26.3.51.1426.3.51.152
19726.3.51.16/3026.3.51.17 to 26.3.51.1826.3.51.192
19826.3.51.20/3026.3.51.21 to 26.3.51.2226.3.51.232
19926.3.51.24/3026.3.51.25 to 26.3.51.2626.3.51.272
20026.3.51.28/3026.3.51.29 to 26.3.51.3026.3.51.312
20126.3.51.32/3026.3.51.33 to 26.3.51.3426.3.51.352
20226.3.51.36/3026.3.51.37 to 26.3.51.3826.3.51.392
20326.3.51.40/3026.3.51.41 to 26.3.51.4226.3.51.432
20426.3.51.44/3026.3.51.45 to 26.3.51.4626.3.51.472
20526.3.51.48/3026.3.51.49 to 26.3.51.5026.3.51.512
20626.3.51.52/3026.3.51.53 to 26.3.51.5426.3.51.552
20726.3.51.56/3026.3.51.57 to 26.3.51.5826.3.51.592
20826.3.51.60/3026.3.51.61 to 26.3.51.6226.3.51.632
20926.3.51.64/3026.3.51.65 to 26.3.51.6626.3.51.672
21026.3.51.68/3026.3.51.69 to 26.3.51.7026.3.51.712
21126.3.51.72/3026.3.51.73 to 26.3.51.7426.3.51.752
21226.3.51.76/3026.3.51.77 to 26.3.51.7826.3.51.792
21326.3.51.80/3026.3.51.81 to 26.3.51.8226.3.51.832
21426.3.51.84/3026.3.51.85 to 26.3.51.8626.3.51.872
21526.3.51.88/3026.3.51.89 to 26.3.51.9026.3.51.912
21626.3.51.92/3026.3.51.93 to 26.3.51.9426.3.51.952
21726.3.51.96/3026.3.51.97 to 26.3.51.9826.3.51.992
21826.3.51.100/3026.3.51.101 to 26.3.51.10226.3.51.1032
21926.3.51.104/3026.3.51.105 to 26.3.51.10626.3.51.1072
22026.3.51.108/3026.3.51.109 to 26.3.51.11026.3.51.1112
22126.3.51.112/3026.3.51.113 to 26.3.51.11426.3.51.1152
22226.3.51.116/3026.3.51.117 to 26.3.51.11826.3.51.1192
22326.3.51.120/3026.3.51.121 to 26.3.51.12226.3.51.1232
22426.3.51.124/3026.3.51.125 to 26.3.51.12626.3.51.1272
22526.3.51.128/3026.3.51.129 to 26.3.51.13026.3.51.1312
22626.3.51.132/3026.3.51.133 to 26.3.51.13426.3.51.1352
22726.3.51.136/3026.3.51.137 to 26.3.51.13826.3.51.1392
22826.3.51.140/3026.3.51.141 to 26.3.51.14226.3.51.1432
22926.3.51.144/3026.3.51.145 to 26.3.51.14626.3.51.1472
23026.3.51.148/3026.3.51.149 to 26.3.51.15026.3.51.1512
23126.3.51.152/3026.3.51.153 to 26.3.51.15426.3.51.1552
23226.3.51.156/3026.3.51.157 to 26.3.51.15826.3.51.1592
23326.3.51.160/3026.3.51.161 to 26.3.51.16226.3.51.1632
23426.3.51.164/3026.3.51.165 to 26.3.51.16626.3.51.1672
23526.3.51.168/3026.3.51.169 to 26.3.51.17026.3.51.1712
23626.3.51.172/3026.3.51.173 to 26.3.51.17426.3.51.1752
23726.3.51.176/3026.3.51.177 to 26.3.51.17826.3.51.1792
23826.3.51.180/3026.3.51.181 to 26.3.51.18226.3.51.1832
23926.3.51.184/3026.3.51.185 to 26.3.51.18626.3.51.1872
24026.3.51.188/3026.3.51.189 to 26.3.51.19026.3.51.1912
24126.3.51.192/3026.3.51.193 to 26.3.51.19426.3.51.1952
24226.3.51.196/3026.3.51.197 to 26.3.51.19826.3.51.1992
24326.3.51.200/3026.3.51.201 to 26.3.51.20226.3.51.2032
24426.3.51.204/3026.3.51.205 to 26.3.51.20626.3.51.2072
24526.3.51.208/3026.3.51.209 to 26.3.51.21026.3.51.2112
24626.3.51.212/3026.3.51.213 to 26.3.51.21426.3.51.2152
24726.3.51.216/3026.3.51.217 to 26.3.51.21826.3.51.2192
24826.3.51.220/3026.3.51.221 to 26.3.51.22226.3.51.2232
24926.3.51.224/3026.3.51.225 to 26.3.51.22626.3.51.2272
25026.3.51.228/3026.3.51.229 to 26.3.51.23026.3.51.2312
25126.3.51.232/3026.3.51.233 to 26.3.51.23426.3.51.2352
25226.3.51.236/3026.3.51.237 to 26.3.51.23826.3.51.2392
25326.3.51.240/3026.3.51.241 to 26.3.51.24226.3.51.2432
25426.3.51.244/3026.3.51.245 to 26.3.51.24626.3.51.2472
25526.3.51.248/3026.3.51.249 to 26.3.51.25026.3.51.2512
25626.3.51.252/3026.3.51.253 to 26.3.51.25426.3.51.2552

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.