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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.

Network34.45.0.0/18
Usable hosts16,382
Subnet mask255.255.192.0
Addresses16,384
Network address
34.45.0.0
Broadcast address
34.45.63.255
First usable
34.45.0.1
Last usable
34.45.63.254
Usable hosts
16,382 (16,384 less the network and broadcast addresses)
Subnet mask
255.255.192.0
Wildcard mask
0.0.63.255 (Cisco ACLs, OSPF)
Prefix length
/18
Type
Public public
Old class
A (default /8)
As numbers
Hex 222D0000 · Integer 573374464 to 573390847
Reverse DNS zones
0.45.34.in-addr.arpa
1.45.34.in-addr.arpa
2.45.34.in-addr.arpa
3.45.34.in-addr.arpa
4.45.34.in-addr.arpa
5.45.34.in-addr.arpa
6.45.34.in-addr.arpa
7.45.34.in-addr.arpa
8.45.34.in-addr.arpa
9.45.34.in-addr.arpa
10.45.34.in-addr.arpa
11.45.34.in-addr.arpa
12.45.34.in-addr.arpa
13.45.34.in-addr.arpa
14.45.34.in-addr.arpa
15.45.34.in-addr.arpa
and 48 more
/18 is not on a 8-bit boundary, so it takes 64 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00100010.00101101.00000000.0000000034.45.0.0
Subnet mask11111111.11111111.11000000.00000000255.255.192.0
Network00100010.00101101.00000000.0000000034.45.0.0
Broadcast00100010.00101101.00111111.1111111134.45.63.255
Split into smaller subnets/30
/19 (2)/20 (4)/21 (8)/22 (16)/23 (32)/24 (64)/25 (128)/26 (256)/27 (512)/28 (1,024)/29 (2,048)/30 (4,096)

34.45.0.0/18 makes 4,096 subnets of /30; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
134.45.0.0/3034.45.0.1 to 34.45.0.234.45.0.32
234.45.0.4/3034.45.0.5 to 34.45.0.634.45.0.72
334.45.0.8/3034.45.0.9 to 34.45.0.1034.45.0.112
434.45.0.12/3034.45.0.13 to 34.45.0.1434.45.0.152
534.45.0.16/3034.45.0.17 to 34.45.0.1834.45.0.192
634.45.0.20/3034.45.0.21 to 34.45.0.2234.45.0.232
734.45.0.24/3034.45.0.25 to 34.45.0.2634.45.0.272
834.45.0.28/3034.45.0.29 to 34.45.0.3034.45.0.312
934.45.0.32/3034.45.0.33 to 34.45.0.3434.45.0.352
1034.45.0.36/3034.45.0.37 to 34.45.0.3834.45.0.392
1134.45.0.40/3034.45.0.41 to 34.45.0.4234.45.0.432
1234.45.0.44/3034.45.0.45 to 34.45.0.4634.45.0.472
1334.45.0.48/3034.45.0.49 to 34.45.0.5034.45.0.512
1434.45.0.52/3034.45.0.53 to 34.45.0.5434.45.0.552
1534.45.0.56/3034.45.0.57 to 34.45.0.5834.45.0.592
1634.45.0.60/3034.45.0.61 to 34.45.0.6234.45.0.632
1734.45.0.64/3034.45.0.65 to 34.45.0.6634.45.0.672
1834.45.0.68/3034.45.0.69 to 34.45.0.7034.45.0.712
1934.45.0.72/3034.45.0.73 to 34.45.0.7434.45.0.752
2034.45.0.76/3034.45.0.77 to 34.45.0.7834.45.0.792
2134.45.0.80/3034.45.0.81 to 34.45.0.8234.45.0.832
2234.45.0.84/3034.45.0.85 to 34.45.0.8634.45.0.872
2334.45.0.88/3034.45.0.89 to 34.45.0.9034.45.0.912
2434.45.0.92/3034.45.0.93 to 34.45.0.9434.45.0.952
2534.45.0.96/3034.45.0.97 to 34.45.0.9834.45.0.992
2634.45.0.100/3034.45.0.101 to 34.45.0.10234.45.0.1032
2734.45.0.104/3034.45.0.105 to 34.45.0.10634.45.0.1072
2834.45.0.108/3034.45.0.109 to 34.45.0.11034.45.0.1112
2934.45.0.112/3034.45.0.113 to 34.45.0.11434.45.0.1152
3034.45.0.116/3034.45.0.117 to 34.45.0.11834.45.0.1192
3134.45.0.120/3034.45.0.121 to 34.45.0.12234.45.0.1232
3234.45.0.124/3034.45.0.125 to 34.45.0.12634.45.0.1272
3334.45.0.128/3034.45.0.129 to 34.45.0.13034.45.0.1312
3434.45.0.132/3034.45.0.133 to 34.45.0.13434.45.0.1352
3534.45.0.136/3034.45.0.137 to 34.45.0.13834.45.0.1392
3634.45.0.140/3034.45.0.141 to 34.45.0.14234.45.0.1432
3734.45.0.144/3034.45.0.145 to 34.45.0.14634.45.0.1472
3834.45.0.148/3034.45.0.149 to 34.45.0.15034.45.0.1512
3934.45.0.152/3034.45.0.153 to 34.45.0.15434.45.0.1552
4034.45.0.156/3034.45.0.157 to 34.45.0.15834.45.0.1592
4134.45.0.160/3034.45.0.161 to 34.45.0.16234.45.0.1632
4234.45.0.164/3034.45.0.165 to 34.45.0.16634.45.0.1672
4334.45.0.168/3034.45.0.169 to 34.45.0.17034.45.0.1712
4434.45.0.172/3034.45.0.173 to 34.45.0.17434.45.0.1752
4534.45.0.176/3034.45.0.177 to 34.45.0.17834.45.0.1792
4634.45.0.180/3034.45.0.181 to 34.45.0.18234.45.0.1832
4734.45.0.184/3034.45.0.185 to 34.45.0.18634.45.0.1872
4834.45.0.188/3034.45.0.189 to 34.45.0.19034.45.0.1912
4934.45.0.192/3034.45.0.193 to 34.45.0.19434.45.0.1952
5034.45.0.196/3034.45.0.197 to 34.45.0.19834.45.0.1992
5134.45.0.200/3034.45.0.201 to 34.45.0.20234.45.0.2032
5234.45.0.204/3034.45.0.205 to 34.45.0.20634.45.0.2072
5334.45.0.208/3034.45.0.209 to 34.45.0.21034.45.0.2112
5434.45.0.212/3034.45.0.213 to 34.45.0.21434.45.0.2152
5534.45.0.216/3034.45.0.217 to 34.45.0.21834.45.0.2192
5634.45.0.220/3034.45.0.221 to 34.45.0.22234.45.0.2232
5734.45.0.224/3034.45.0.225 to 34.45.0.22634.45.0.2272
5834.45.0.228/3034.45.0.229 to 34.45.0.23034.45.0.2312
5934.45.0.232/3034.45.0.233 to 34.45.0.23434.45.0.2352
6034.45.0.236/3034.45.0.237 to 34.45.0.23834.45.0.2392
6134.45.0.240/3034.45.0.241 to 34.45.0.24234.45.0.2432
6234.45.0.244/3034.45.0.245 to 34.45.0.24634.45.0.2472
6334.45.0.248/3034.45.0.249 to 34.45.0.25034.45.0.2512
6434.45.0.252/3034.45.0.253 to 34.45.0.25434.45.0.2552
6534.45.1.0/3034.45.1.1 to 34.45.1.234.45.1.32
6634.45.1.4/3034.45.1.5 to 34.45.1.634.45.1.72
6734.45.1.8/3034.45.1.9 to 34.45.1.1034.45.1.112
6834.45.1.12/3034.45.1.13 to 34.45.1.1434.45.1.152
6934.45.1.16/3034.45.1.17 to 34.45.1.1834.45.1.192
7034.45.1.20/3034.45.1.21 to 34.45.1.2234.45.1.232
7134.45.1.24/3034.45.1.25 to 34.45.1.2634.45.1.272
7234.45.1.28/3034.45.1.29 to 34.45.1.3034.45.1.312
7334.45.1.32/3034.45.1.33 to 34.45.1.3434.45.1.352
7434.45.1.36/3034.45.1.37 to 34.45.1.3834.45.1.392
7534.45.1.40/3034.45.1.41 to 34.45.1.4234.45.1.432
7634.45.1.44/3034.45.1.45 to 34.45.1.4634.45.1.472
7734.45.1.48/3034.45.1.49 to 34.45.1.5034.45.1.512
7834.45.1.52/3034.45.1.53 to 34.45.1.5434.45.1.552
7934.45.1.56/3034.45.1.57 to 34.45.1.5834.45.1.592
8034.45.1.60/3034.45.1.61 to 34.45.1.6234.45.1.632
8134.45.1.64/3034.45.1.65 to 34.45.1.6634.45.1.672
8234.45.1.68/3034.45.1.69 to 34.45.1.7034.45.1.712
8334.45.1.72/3034.45.1.73 to 34.45.1.7434.45.1.752
8434.45.1.76/3034.45.1.77 to 34.45.1.7834.45.1.792
8534.45.1.80/3034.45.1.81 to 34.45.1.8234.45.1.832
8634.45.1.84/3034.45.1.85 to 34.45.1.8634.45.1.872
8734.45.1.88/3034.45.1.89 to 34.45.1.9034.45.1.912
8834.45.1.92/3034.45.1.93 to 34.45.1.9434.45.1.952
8934.45.1.96/3034.45.1.97 to 34.45.1.9834.45.1.992
9034.45.1.100/3034.45.1.101 to 34.45.1.10234.45.1.1032
9134.45.1.104/3034.45.1.105 to 34.45.1.10634.45.1.1072
9234.45.1.108/3034.45.1.109 to 34.45.1.11034.45.1.1112
9334.45.1.112/3034.45.1.113 to 34.45.1.11434.45.1.1152
9434.45.1.116/3034.45.1.117 to 34.45.1.11834.45.1.1192
9534.45.1.120/3034.45.1.121 to 34.45.1.12234.45.1.1232
9634.45.1.124/3034.45.1.125 to 34.45.1.12634.45.1.1272
9734.45.1.128/3034.45.1.129 to 34.45.1.13034.45.1.1312
9834.45.1.132/3034.45.1.133 to 34.45.1.13434.45.1.1352
9934.45.1.136/3034.45.1.137 to 34.45.1.13834.45.1.1392
10034.45.1.140/3034.45.1.141 to 34.45.1.14234.45.1.1432
10134.45.1.144/3034.45.1.145 to 34.45.1.14634.45.1.1472
10234.45.1.148/3034.45.1.149 to 34.45.1.15034.45.1.1512
10334.45.1.152/3034.45.1.153 to 34.45.1.15434.45.1.1552
10434.45.1.156/3034.45.1.157 to 34.45.1.15834.45.1.1592
10534.45.1.160/3034.45.1.161 to 34.45.1.16234.45.1.1632
10634.45.1.164/3034.45.1.165 to 34.45.1.16634.45.1.1672
10734.45.1.168/3034.45.1.169 to 34.45.1.17034.45.1.1712
10834.45.1.172/3034.45.1.173 to 34.45.1.17434.45.1.1752
10934.45.1.176/3034.45.1.177 to 34.45.1.17834.45.1.1792
11034.45.1.180/3034.45.1.181 to 34.45.1.18234.45.1.1832
11134.45.1.184/3034.45.1.185 to 34.45.1.18634.45.1.1872
11234.45.1.188/3034.45.1.189 to 34.45.1.19034.45.1.1912
11334.45.1.192/3034.45.1.193 to 34.45.1.19434.45.1.1952
11434.45.1.196/3034.45.1.197 to 34.45.1.19834.45.1.1992
11534.45.1.200/3034.45.1.201 to 34.45.1.20234.45.1.2032
11634.45.1.204/3034.45.1.205 to 34.45.1.20634.45.1.2072
11734.45.1.208/3034.45.1.209 to 34.45.1.21034.45.1.2112
11834.45.1.212/3034.45.1.213 to 34.45.1.21434.45.1.2152
11934.45.1.216/3034.45.1.217 to 34.45.1.21834.45.1.2192
12034.45.1.220/3034.45.1.221 to 34.45.1.22234.45.1.2232
12134.45.1.224/3034.45.1.225 to 34.45.1.22634.45.1.2272
12234.45.1.228/3034.45.1.229 to 34.45.1.23034.45.1.2312
12334.45.1.232/3034.45.1.233 to 34.45.1.23434.45.1.2352
12434.45.1.236/3034.45.1.237 to 34.45.1.23834.45.1.2392
12534.45.1.240/3034.45.1.241 to 34.45.1.24234.45.1.2432
12634.45.1.244/3034.45.1.245 to 34.45.1.24634.45.1.2472
12734.45.1.248/3034.45.1.249 to 34.45.1.25034.45.1.2512
12834.45.1.252/3034.45.1.253 to 34.45.1.25434.45.1.2552
12934.45.2.0/3034.45.2.1 to 34.45.2.234.45.2.32
13034.45.2.4/3034.45.2.5 to 34.45.2.634.45.2.72
13134.45.2.8/3034.45.2.9 to 34.45.2.1034.45.2.112
13234.45.2.12/3034.45.2.13 to 34.45.2.1434.45.2.152
13334.45.2.16/3034.45.2.17 to 34.45.2.1834.45.2.192
13434.45.2.20/3034.45.2.21 to 34.45.2.2234.45.2.232
13534.45.2.24/3034.45.2.25 to 34.45.2.2634.45.2.272
13634.45.2.28/3034.45.2.29 to 34.45.2.3034.45.2.312
13734.45.2.32/3034.45.2.33 to 34.45.2.3434.45.2.352
13834.45.2.36/3034.45.2.37 to 34.45.2.3834.45.2.392
13934.45.2.40/3034.45.2.41 to 34.45.2.4234.45.2.432
14034.45.2.44/3034.45.2.45 to 34.45.2.4634.45.2.472
14134.45.2.48/3034.45.2.49 to 34.45.2.5034.45.2.512
14234.45.2.52/3034.45.2.53 to 34.45.2.5434.45.2.552
14334.45.2.56/3034.45.2.57 to 34.45.2.5834.45.2.592
14434.45.2.60/3034.45.2.61 to 34.45.2.6234.45.2.632
14534.45.2.64/3034.45.2.65 to 34.45.2.6634.45.2.672
14634.45.2.68/3034.45.2.69 to 34.45.2.7034.45.2.712
14734.45.2.72/3034.45.2.73 to 34.45.2.7434.45.2.752
14834.45.2.76/3034.45.2.77 to 34.45.2.7834.45.2.792
14934.45.2.80/3034.45.2.81 to 34.45.2.8234.45.2.832
15034.45.2.84/3034.45.2.85 to 34.45.2.8634.45.2.872
15134.45.2.88/3034.45.2.89 to 34.45.2.9034.45.2.912
15234.45.2.92/3034.45.2.93 to 34.45.2.9434.45.2.952
15334.45.2.96/3034.45.2.97 to 34.45.2.9834.45.2.992
15434.45.2.100/3034.45.2.101 to 34.45.2.10234.45.2.1032
15534.45.2.104/3034.45.2.105 to 34.45.2.10634.45.2.1072
15634.45.2.108/3034.45.2.109 to 34.45.2.11034.45.2.1112
15734.45.2.112/3034.45.2.113 to 34.45.2.11434.45.2.1152
15834.45.2.116/3034.45.2.117 to 34.45.2.11834.45.2.1192
15934.45.2.120/3034.45.2.121 to 34.45.2.12234.45.2.1232
16034.45.2.124/3034.45.2.125 to 34.45.2.12634.45.2.1272
16134.45.2.128/3034.45.2.129 to 34.45.2.13034.45.2.1312
16234.45.2.132/3034.45.2.133 to 34.45.2.13434.45.2.1352
16334.45.2.136/3034.45.2.137 to 34.45.2.13834.45.2.1392
16434.45.2.140/3034.45.2.141 to 34.45.2.14234.45.2.1432
16534.45.2.144/3034.45.2.145 to 34.45.2.14634.45.2.1472
16634.45.2.148/3034.45.2.149 to 34.45.2.15034.45.2.1512
16734.45.2.152/3034.45.2.153 to 34.45.2.15434.45.2.1552
16834.45.2.156/3034.45.2.157 to 34.45.2.15834.45.2.1592
16934.45.2.160/3034.45.2.161 to 34.45.2.16234.45.2.1632
17034.45.2.164/3034.45.2.165 to 34.45.2.16634.45.2.1672
17134.45.2.168/3034.45.2.169 to 34.45.2.17034.45.2.1712
17234.45.2.172/3034.45.2.173 to 34.45.2.17434.45.2.1752
17334.45.2.176/3034.45.2.177 to 34.45.2.17834.45.2.1792
17434.45.2.180/3034.45.2.181 to 34.45.2.18234.45.2.1832
17534.45.2.184/3034.45.2.185 to 34.45.2.18634.45.2.1872
17634.45.2.188/3034.45.2.189 to 34.45.2.19034.45.2.1912
17734.45.2.192/3034.45.2.193 to 34.45.2.19434.45.2.1952
17834.45.2.196/3034.45.2.197 to 34.45.2.19834.45.2.1992
17934.45.2.200/3034.45.2.201 to 34.45.2.20234.45.2.2032
18034.45.2.204/3034.45.2.205 to 34.45.2.20634.45.2.2072
18134.45.2.208/3034.45.2.209 to 34.45.2.21034.45.2.2112
18234.45.2.212/3034.45.2.213 to 34.45.2.21434.45.2.2152
18334.45.2.216/3034.45.2.217 to 34.45.2.21834.45.2.2192
18434.45.2.220/3034.45.2.221 to 34.45.2.22234.45.2.2232
18534.45.2.224/3034.45.2.225 to 34.45.2.22634.45.2.2272
18634.45.2.228/3034.45.2.229 to 34.45.2.23034.45.2.2312
18734.45.2.232/3034.45.2.233 to 34.45.2.23434.45.2.2352
18834.45.2.236/3034.45.2.237 to 34.45.2.23834.45.2.2392
18934.45.2.240/3034.45.2.241 to 34.45.2.24234.45.2.2432
19034.45.2.244/3034.45.2.245 to 34.45.2.24634.45.2.2472
19134.45.2.248/3034.45.2.249 to 34.45.2.25034.45.2.2512
19234.45.2.252/3034.45.2.253 to 34.45.2.25434.45.2.2552
19334.45.3.0/3034.45.3.1 to 34.45.3.234.45.3.32
19434.45.3.4/3034.45.3.5 to 34.45.3.634.45.3.72
19534.45.3.8/3034.45.3.9 to 34.45.3.1034.45.3.112
19634.45.3.12/3034.45.3.13 to 34.45.3.1434.45.3.152
19734.45.3.16/3034.45.3.17 to 34.45.3.1834.45.3.192
19834.45.3.20/3034.45.3.21 to 34.45.3.2234.45.3.232
19934.45.3.24/3034.45.3.25 to 34.45.3.2634.45.3.272
20034.45.3.28/3034.45.3.29 to 34.45.3.3034.45.3.312
20134.45.3.32/3034.45.3.33 to 34.45.3.3434.45.3.352
20234.45.3.36/3034.45.3.37 to 34.45.3.3834.45.3.392
20334.45.3.40/3034.45.3.41 to 34.45.3.4234.45.3.432
20434.45.3.44/3034.45.3.45 to 34.45.3.4634.45.3.472
20534.45.3.48/3034.45.3.49 to 34.45.3.5034.45.3.512
20634.45.3.52/3034.45.3.53 to 34.45.3.5434.45.3.552
20734.45.3.56/3034.45.3.57 to 34.45.3.5834.45.3.592
20834.45.3.60/3034.45.3.61 to 34.45.3.6234.45.3.632
20934.45.3.64/3034.45.3.65 to 34.45.3.6634.45.3.672
21034.45.3.68/3034.45.3.69 to 34.45.3.7034.45.3.712
21134.45.3.72/3034.45.3.73 to 34.45.3.7434.45.3.752
21234.45.3.76/3034.45.3.77 to 34.45.3.7834.45.3.792
21334.45.3.80/3034.45.3.81 to 34.45.3.8234.45.3.832
21434.45.3.84/3034.45.3.85 to 34.45.3.8634.45.3.872
21534.45.3.88/3034.45.3.89 to 34.45.3.9034.45.3.912
21634.45.3.92/3034.45.3.93 to 34.45.3.9434.45.3.952
21734.45.3.96/3034.45.3.97 to 34.45.3.9834.45.3.992
21834.45.3.100/3034.45.3.101 to 34.45.3.10234.45.3.1032
21934.45.3.104/3034.45.3.105 to 34.45.3.10634.45.3.1072
22034.45.3.108/3034.45.3.109 to 34.45.3.11034.45.3.1112
22134.45.3.112/3034.45.3.113 to 34.45.3.11434.45.3.1152
22234.45.3.116/3034.45.3.117 to 34.45.3.11834.45.3.1192
22334.45.3.120/3034.45.3.121 to 34.45.3.12234.45.3.1232
22434.45.3.124/3034.45.3.125 to 34.45.3.12634.45.3.1272
22534.45.3.128/3034.45.3.129 to 34.45.3.13034.45.3.1312
22634.45.3.132/3034.45.3.133 to 34.45.3.13434.45.3.1352
22734.45.3.136/3034.45.3.137 to 34.45.3.13834.45.3.1392
22834.45.3.140/3034.45.3.141 to 34.45.3.14234.45.3.1432
22934.45.3.144/3034.45.3.145 to 34.45.3.14634.45.3.1472
23034.45.3.148/3034.45.3.149 to 34.45.3.15034.45.3.1512
23134.45.3.152/3034.45.3.153 to 34.45.3.15434.45.3.1552
23234.45.3.156/3034.45.3.157 to 34.45.3.15834.45.3.1592
23334.45.3.160/3034.45.3.161 to 34.45.3.16234.45.3.1632
23434.45.3.164/3034.45.3.165 to 34.45.3.16634.45.3.1672
23534.45.3.168/3034.45.3.169 to 34.45.3.17034.45.3.1712
23634.45.3.172/3034.45.3.173 to 34.45.3.17434.45.3.1752
23734.45.3.176/3034.45.3.177 to 34.45.3.17834.45.3.1792
23834.45.3.180/3034.45.3.181 to 34.45.3.18234.45.3.1832
23934.45.3.184/3034.45.3.185 to 34.45.3.18634.45.3.1872
24034.45.3.188/3034.45.3.189 to 34.45.3.19034.45.3.1912
24134.45.3.192/3034.45.3.193 to 34.45.3.19434.45.3.1952
24234.45.3.196/3034.45.3.197 to 34.45.3.19834.45.3.1992
24334.45.3.200/3034.45.3.201 to 34.45.3.20234.45.3.2032
24434.45.3.204/3034.45.3.205 to 34.45.3.20634.45.3.2072
24534.45.3.208/3034.45.3.209 to 34.45.3.21034.45.3.2112
24634.45.3.212/3034.45.3.213 to 34.45.3.21434.45.3.2152
24734.45.3.216/3034.45.3.217 to 34.45.3.21834.45.3.2192
24834.45.3.220/3034.45.3.221 to 34.45.3.22234.45.3.2232
24934.45.3.224/3034.45.3.225 to 34.45.3.22634.45.3.2272
25034.45.3.228/3034.45.3.229 to 34.45.3.23034.45.3.2312
25134.45.3.232/3034.45.3.233 to 34.45.3.23434.45.3.2352
25234.45.3.236/3034.45.3.237 to 34.45.3.23834.45.3.2392
25334.45.3.240/3034.45.3.241 to 34.45.3.24234.45.3.2432
25434.45.3.244/3034.45.3.245 to 34.45.3.24634.45.3.2472
25534.45.3.248/3034.45.3.249 to 34.45.3.25034.45.3.2512
25634.45.3.252/3034.45.3.253 to 34.45.3.25434.45.3.2552

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.