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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.

Network10.11.80.0/20
Usable hosts4,094
Subnet mask255.255.240.0
Addresses4,096
Network address
10.11.80.0
Broadcast address
10.11.95.255
First usable
10.11.80.1
Last usable
10.11.95.254
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
Private (RFC 1918) 10.0.0.0/8
Office and home networks; not routed on the internet
Old class
A (default /8)
As numbers
Hex 0A0B5000 · Integer 168513536 to 168517631
Reverse DNS zones
80.11.10.in-addr.arpa
81.11.10.in-addr.arpa
82.11.10.in-addr.arpa
83.11.10.in-addr.arpa
84.11.10.in-addr.arpa
85.11.10.in-addr.arpa
86.11.10.in-addr.arpa
87.11.10.in-addr.arpa
88.11.10.in-addr.arpa
89.11.10.in-addr.arpa
90.11.10.in-addr.arpa
91.11.10.in-addr.arpa
92.11.10.in-addr.arpa
93.11.10.in-addr.arpa
94.11.10.in-addr.arpa
95.11.10.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
Address00001010.00001011.01010000.0000000010.11.80.0
Subnet mask11111111.11111111.11110000.00000000255.255.240.0
Network00001010.00001011.01010000.0000000010.11.80.0
Broadcast00001010.00001011.01011111.1111111110.11.95.255
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)

10.11.80.0/20 makes 1,024 subnets of /30; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
110.11.80.0/3010.11.80.1 to 10.11.80.210.11.80.32
210.11.80.4/3010.11.80.5 to 10.11.80.610.11.80.72
310.11.80.8/3010.11.80.9 to 10.11.80.1010.11.80.112
410.11.80.12/3010.11.80.13 to 10.11.80.1410.11.80.152
510.11.80.16/3010.11.80.17 to 10.11.80.1810.11.80.192
610.11.80.20/3010.11.80.21 to 10.11.80.2210.11.80.232
710.11.80.24/3010.11.80.25 to 10.11.80.2610.11.80.272
810.11.80.28/3010.11.80.29 to 10.11.80.3010.11.80.312
910.11.80.32/3010.11.80.33 to 10.11.80.3410.11.80.352
1010.11.80.36/3010.11.80.37 to 10.11.80.3810.11.80.392
1110.11.80.40/3010.11.80.41 to 10.11.80.4210.11.80.432
1210.11.80.44/3010.11.80.45 to 10.11.80.4610.11.80.472
1310.11.80.48/3010.11.80.49 to 10.11.80.5010.11.80.512
1410.11.80.52/3010.11.80.53 to 10.11.80.5410.11.80.552
1510.11.80.56/3010.11.80.57 to 10.11.80.5810.11.80.592
1610.11.80.60/3010.11.80.61 to 10.11.80.6210.11.80.632
1710.11.80.64/3010.11.80.65 to 10.11.80.6610.11.80.672
1810.11.80.68/3010.11.80.69 to 10.11.80.7010.11.80.712
1910.11.80.72/3010.11.80.73 to 10.11.80.7410.11.80.752
2010.11.80.76/3010.11.80.77 to 10.11.80.7810.11.80.792
2110.11.80.80/3010.11.80.81 to 10.11.80.8210.11.80.832
2210.11.80.84/3010.11.80.85 to 10.11.80.8610.11.80.872
2310.11.80.88/3010.11.80.89 to 10.11.80.9010.11.80.912
2410.11.80.92/3010.11.80.93 to 10.11.80.9410.11.80.952
2510.11.80.96/3010.11.80.97 to 10.11.80.9810.11.80.992
2610.11.80.100/3010.11.80.101 to 10.11.80.10210.11.80.1032
2710.11.80.104/3010.11.80.105 to 10.11.80.10610.11.80.1072
2810.11.80.108/3010.11.80.109 to 10.11.80.11010.11.80.1112
2910.11.80.112/3010.11.80.113 to 10.11.80.11410.11.80.1152
3010.11.80.116/3010.11.80.117 to 10.11.80.11810.11.80.1192
3110.11.80.120/3010.11.80.121 to 10.11.80.12210.11.80.1232
3210.11.80.124/3010.11.80.125 to 10.11.80.12610.11.80.1272
3310.11.80.128/3010.11.80.129 to 10.11.80.13010.11.80.1312
3410.11.80.132/3010.11.80.133 to 10.11.80.13410.11.80.1352
3510.11.80.136/3010.11.80.137 to 10.11.80.13810.11.80.1392
3610.11.80.140/3010.11.80.141 to 10.11.80.14210.11.80.1432
3710.11.80.144/3010.11.80.145 to 10.11.80.14610.11.80.1472
3810.11.80.148/3010.11.80.149 to 10.11.80.15010.11.80.1512
3910.11.80.152/3010.11.80.153 to 10.11.80.15410.11.80.1552
4010.11.80.156/3010.11.80.157 to 10.11.80.15810.11.80.1592
4110.11.80.160/3010.11.80.161 to 10.11.80.16210.11.80.1632
4210.11.80.164/3010.11.80.165 to 10.11.80.16610.11.80.1672
4310.11.80.168/3010.11.80.169 to 10.11.80.17010.11.80.1712
4410.11.80.172/3010.11.80.173 to 10.11.80.17410.11.80.1752
4510.11.80.176/3010.11.80.177 to 10.11.80.17810.11.80.1792
4610.11.80.180/3010.11.80.181 to 10.11.80.18210.11.80.1832
4710.11.80.184/3010.11.80.185 to 10.11.80.18610.11.80.1872
4810.11.80.188/3010.11.80.189 to 10.11.80.19010.11.80.1912
4910.11.80.192/3010.11.80.193 to 10.11.80.19410.11.80.1952
5010.11.80.196/3010.11.80.197 to 10.11.80.19810.11.80.1992
5110.11.80.200/3010.11.80.201 to 10.11.80.20210.11.80.2032
5210.11.80.204/3010.11.80.205 to 10.11.80.20610.11.80.2072
5310.11.80.208/3010.11.80.209 to 10.11.80.21010.11.80.2112
5410.11.80.212/3010.11.80.213 to 10.11.80.21410.11.80.2152
5510.11.80.216/3010.11.80.217 to 10.11.80.21810.11.80.2192
5610.11.80.220/3010.11.80.221 to 10.11.80.22210.11.80.2232
5710.11.80.224/3010.11.80.225 to 10.11.80.22610.11.80.2272
5810.11.80.228/3010.11.80.229 to 10.11.80.23010.11.80.2312
5910.11.80.232/3010.11.80.233 to 10.11.80.23410.11.80.2352
6010.11.80.236/3010.11.80.237 to 10.11.80.23810.11.80.2392
6110.11.80.240/3010.11.80.241 to 10.11.80.24210.11.80.2432
6210.11.80.244/3010.11.80.245 to 10.11.80.24610.11.80.2472
6310.11.80.248/3010.11.80.249 to 10.11.80.25010.11.80.2512
6410.11.80.252/3010.11.80.253 to 10.11.80.25410.11.80.2552
6510.11.81.0/3010.11.81.1 to 10.11.81.210.11.81.32
6610.11.81.4/3010.11.81.5 to 10.11.81.610.11.81.72
6710.11.81.8/3010.11.81.9 to 10.11.81.1010.11.81.112
6810.11.81.12/3010.11.81.13 to 10.11.81.1410.11.81.152
6910.11.81.16/3010.11.81.17 to 10.11.81.1810.11.81.192
7010.11.81.20/3010.11.81.21 to 10.11.81.2210.11.81.232
7110.11.81.24/3010.11.81.25 to 10.11.81.2610.11.81.272
7210.11.81.28/3010.11.81.29 to 10.11.81.3010.11.81.312
7310.11.81.32/3010.11.81.33 to 10.11.81.3410.11.81.352
7410.11.81.36/3010.11.81.37 to 10.11.81.3810.11.81.392
7510.11.81.40/3010.11.81.41 to 10.11.81.4210.11.81.432
7610.11.81.44/3010.11.81.45 to 10.11.81.4610.11.81.472
7710.11.81.48/3010.11.81.49 to 10.11.81.5010.11.81.512
7810.11.81.52/3010.11.81.53 to 10.11.81.5410.11.81.552
7910.11.81.56/3010.11.81.57 to 10.11.81.5810.11.81.592
8010.11.81.60/3010.11.81.61 to 10.11.81.6210.11.81.632
8110.11.81.64/3010.11.81.65 to 10.11.81.6610.11.81.672
8210.11.81.68/3010.11.81.69 to 10.11.81.7010.11.81.712
8310.11.81.72/3010.11.81.73 to 10.11.81.7410.11.81.752
8410.11.81.76/3010.11.81.77 to 10.11.81.7810.11.81.792
8510.11.81.80/3010.11.81.81 to 10.11.81.8210.11.81.832
8610.11.81.84/3010.11.81.85 to 10.11.81.8610.11.81.872
8710.11.81.88/3010.11.81.89 to 10.11.81.9010.11.81.912
8810.11.81.92/3010.11.81.93 to 10.11.81.9410.11.81.952
8910.11.81.96/3010.11.81.97 to 10.11.81.9810.11.81.992
9010.11.81.100/3010.11.81.101 to 10.11.81.10210.11.81.1032
9110.11.81.104/3010.11.81.105 to 10.11.81.10610.11.81.1072
9210.11.81.108/3010.11.81.109 to 10.11.81.11010.11.81.1112
9310.11.81.112/3010.11.81.113 to 10.11.81.11410.11.81.1152
9410.11.81.116/3010.11.81.117 to 10.11.81.11810.11.81.1192
9510.11.81.120/3010.11.81.121 to 10.11.81.12210.11.81.1232
9610.11.81.124/3010.11.81.125 to 10.11.81.12610.11.81.1272
9710.11.81.128/3010.11.81.129 to 10.11.81.13010.11.81.1312
9810.11.81.132/3010.11.81.133 to 10.11.81.13410.11.81.1352
9910.11.81.136/3010.11.81.137 to 10.11.81.13810.11.81.1392
10010.11.81.140/3010.11.81.141 to 10.11.81.14210.11.81.1432
10110.11.81.144/3010.11.81.145 to 10.11.81.14610.11.81.1472
10210.11.81.148/3010.11.81.149 to 10.11.81.15010.11.81.1512
10310.11.81.152/3010.11.81.153 to 10.11.81.15410.11.81.1552
10410.11.81.156/3010.11.81.157 to 10.11.81.15810.11.81.1592
10510.11.81.160/3010.11.81.161 to 10.11.81.16210.11.81.1632
10610.11.81.164/3010.11.81.165 to 10.11.81.16610.11.81.1672
10710.11.81.168/3010.11.81.169 to 10.11.81.17010.11.81.1712
10810.11.81.172/3010.11.81.173 to 10.11.81.17410.11.81.1752
10910.11.81.176/3010.11.81.177 to 10.11.81.17810.11.81.1792
11010.11.81.180/3010.11.81.181 to 10.11.81.18210.11.81.1832
11110.11.81.184/3010.11.81.185 to 10.11.81.18610.11.81.1872
11210.11.81.188/3010.11.81.189 to 10.11.81.19010.11.81.1912
11310.11.81.192/3010.11.81.193 to 10.11.81.19410.11.81.1952
11410.11.81.196/3010.11.81.197 to 10.11.81.19810.11.81.1992
11510.11.81.200/3010.11.81.201 to 10.11.81.20210.11.81.2032
11610.11.81.204/3010.11.81.205 to 10.11.81.20610.11.81.2072
11710.11.81.208/3010.11.81.209 to 10.11.81.21010.11.81.2112
11810.11.81.212/3010.11.81.213 to 10.11.81.21410.11.81.2152
11910.11.81.216/3010.11.81.217 to 10.11.81.21810.11.81.2192
12010.11.81.220/3010.11.81.221 to 10.11.81.22210.11.81.2232
12110.11.81.224/3010.11.81.225 to 10.11.81.22610.11.81.2272
12210.11.81.228/3010.11.81.229 to 10.11.81.23010.11.81.2312
12310.11.81.232/3010.11.81.233 to 10.11.81.23410.11.81.2352
12410.11.81.236/3010.11.81.237 to 10.11.81.23810.11.81.2392
12510.11.81.240/3010.11.81.241 to 10.11.81.24210.11.81.2432
12610.11.81.244/3010.11.81.245 to 10.11.81.24610.11.81.2472
12710.11.81.248/3010.11.81.249 to 10.11.81.25010.11.81.2512
12810.11.81.252/3010.11.81.253 to 10.11.81.25410.11.81.2552
12910.11.82.0/3010.11.82.1 to 10.11.82.210.11.82.32
13010.11.82.4/3010.11.82.5 to 10.11.82.610.11.82.72
13110.11.82.8/3010.11.82.9 to 10.11.82.1010.11.82.112
13210.11.82.12/3010.11.82.13 to 10.11.82.1410.11.82.152
13310.11.82.16/3010.11.82.17 to 10.11.82.1810.11.82.192
13410.11.82.20/3010.11.82.21 to 10.11.82.2210.11.82.232
13510.11.82.24/3010.11.82.25 to 10.11.82.2610.11.82.272
13610.11.82.28/3010.11.82.29 to 10.11.82.3010.11.82.312
13710.11.82.32/3010.11.82.33 to 10.11.82.3410.11.82.352
13810.11.82.36/3010.11.82.37 to 10.11.82.3810.11.82.392
13910.11.82.40/3010.11.82.41 to 10.11.82.4210.11.82.432
14010.11.82.44/3010.11.82.45 to 10.11.82.4610.11.82.472
14110.11.82.48/3010.11.82.49 to 10.11.82.5010.11.82.512
14210.11.82.52/3010.11.82.53 to 10.11.82.5410.11.82.552
14310.11.82.56/3010.11.82.57 to 10.11.82.5810.11.82.592
14410.11.82.60/3010.11.82.61 to 10.11.82.6210.11.82.632
14510.11.82.64/3010.11.82.65 to 10.11.82.6610.11.82.672
14610.11.82.68/3010.11.82.69 to 10.11.82.7010.11.82.712
14710.11.82.72/3010.11.82.73 to 10.11.82.7410.11.82.752
14810.11.82.76/3010.11.82.77 to 10.11.82.7810.11.82.792
14910.11.82.80/3010.11.82.81 to 10.11.82.8210.11.82.832
15010.11.82.84/3010.11.82.85 to 10.11.82.8610.11.82.872
15110.11.82.88/3010.11.82.89 to 10.11.82.9010.11.82.912
15210.11.82.92/3010.11.82.93 to 10.11.82.9410.11.82.952
15310.11.82.96/3010.11.82.97 to 10.11.82.9810.11.82.992
15410.11.82.100/3010.11.82.101 to 10.11.82.10210.11.82.1032
15510.11.82.104/3010.11.82.105 to 10.11.82.10610.11.82.1072
15610.11.82.108/3010.11.82.109 to 10.11.82.11010.11.82.1112
15710.11.82.112/3010.11.82.113 to 10.11.82.11410.11.82.1152
15810.11.82.116/3010.11.82.117 to 10.11.82.11810.11.82.1192
15910.11.82.120/3010.11.82.121 to 10.11.82.12210.11.82.1232
16010.11.82.124/3010.11.82.125 to 10.11.82.12610.11.82.1272
16110.11.82.128/3010.11.82.129 to 10.11.82.13010.11.82.1312
16210.11.82.132/3010.11.82.133 to 10.11.82.13410.11.82.1352
16310.11.82.136/3010.11.82.137 to 10.11.82.13810.11.82.1392
16410.11.82.140/3010.11.82.141 to 10.11.82.14210.11.82.1432
16510.11.82.144/3010.11.82.145 to 10.11.82.14610.11.82.1472
16610.11.82.148/3010.11.82.149 to 10.11.82.15010.11.82.1512
16710.11.82.152/3010.11.82.153 to 10.11.82.15410.11.82.1552
16810.11.82.156/3010.11.82.157 to 10.11.82.15810.11.82.1592
16910.11.82.160/3010.11.82.161 to 10.11.82.16210.11.82.1632
17010.11.82.164/3010.11.82.165 to 10.11.82.16610.11.82.1672
17110.11.82.168/3010.11.82.169 to 10.11.82.17010.11.82.1712
17210.11.82.172/3010.11.82.173 to 10.11.82.17410.11.82.1752
17310.11.82.176/3010.11.82.177 to 10.11.82.17810.11.82.1792
17410.11.82.180/3010.11.82.181 to 10.11.82.18210.11.82.1832
17510.11.82.184/3010.11.82.185 to 10.11.82.18610.11.82.1872
17610.11.82.188/3010.11.82.189 to 10.11.82.19010.11.82.1912
17710.11.82.192/3010.11.82.193 to 10.11.82.19410.11.82.1952
17810.11.82.196/3010.11.82.197 to 10.11.82.19810.11.82.1992
17910.11.82.200/3010.11.82.201 to 10.11.82.20210.11.82.2032
18010.11.82.204/3010.11.82.205 to 10.11.82.20610.11.82.2072
18110.11.82.208/3010.11.82.209 to 10.11.82.21010.11.82.2112
18210.11.82.212/3010.11.82.213 to 10.11.82.21410.11.82.2152
18310.11.82.216/3010.11.82.217 to 10.11.82.21810.11.82.2192
18410.11.82.220/3010.11.82.221 to 10.11.82.22210.11.82.2232
18510.11.82.224/3010.11.82.225 to 10.11.82.22610.11.82.2272
18610.11.82.228/3010.11.82.229 to 10.11.82.23010.11.82.2312
18710.11.82.232/3010.11.82.233 to 10.11.82.23410.11.82.2352
18810.11.82.236/3010.11.82.237 to 10.11.82.23810.11.82.2392
18910.11.82.240/3010.11.82.241 to 10.11.82.24210.11.82.2432
19010.11.82.244/3010.11.82.245 to 10.11.82.24610.11.82.2472
19110.11.82.248/3010.11.82.249 to 10.11.82.25010.11.82.2512
19210.11.82.252/3010.11.82.253 to 10.11.82.25410.11.82.2552
19310.11.83.0/3010.11.83.1 to 10.11.83.210.11.83.32
19410.11.83.4/3010.11.83.5 to 10.11.83.610.11.83.72
19510.11.83.8/3010.11.83.9 to 10.11.83.1010.11.83.112
19610.11.83.12/3010.11.83.13 to 10.11.83.1410.11.83.152
19710.11.83.16/3010.11.83.17 to 10.11.83.1810.11.83.192
19810.11.83.20/3010.11.83.21 to 10.11.83.2210.11.83.232
19910.11.83.24/3010.11.83.25 to 10.11.83.2610.11.83.272
20010.11.83.28/3010.11.83.29 to 10.11.83.3010.11.83.312
20110.11.83.32/3010.11.83.33 to 10.11.83.3410.11.83.352
20210.11.83.36/3010.11.83.37 to 10.11.83.3810.11.83.392
20310.11.83.40/3010.11.83.41 to 10.11.83.4210.11.83.432
20410.11.83.44/3010.11.83.45 to 10.11.83.4610.11.83.472
20510.11.83.48/3010.11.83.49 to 10.11.83.5010.11.83.512
20610.11.83.52/3010.11.83.53 to 10.11.83.5410.11.83.552
20710.11.83.56/3010.11.83.57 to 10.11.83.5810.11.83.592
20810.11.83.60/3010.11.83.61 to 10.11.83.6210.11.83.632
20910.11.83.64/3010.11.83.65 to 10.11.83.6610.11.83.672
21010.11.83.68/3010.11.83.69 to 10.11.83.7010.11.83.712
21110.11.83.72/3010.11.83.73 to 10.11.83.7410.11.83.752
21210.11.83.76/3010.11.83.77 to 10.11.83.7810.11.83.792
21310.11.83.80/3010.11.83.81 to 10.11.83.8210.11.83.832
21410.11.83.84/3010.11.83.85 to 10.11.83.8610.11.83.872
21510.11.83.88/3010.11.83.89 to 10.11.83.9010.11.83.912
21610.11.83.92/3010.11.83.93 to 10.11.83.9410.11.83.952
21710.11.83.96/3010.11.83.97 to 10.11.83.9810.11.83.992
21810.11.83.100/3010.11.83.101 to 10.11.83.10210.11.83.1032
21910.11.83.104/3010.11.83.105 to 10.11.83.10610.11.83.1072
22010.11.83.108/3010.11.83.109 to 10.11.83.11010.11.83.1112
22110.11.83.112/3010.11.83.113 to 10.11.83.11410.11.83.1152
22210.11.83.116/3010.11.83.117 to 10.11.83.11810.11.83.1192
22310.11.83.120/3010.11.83.121 to 10.11.83.12210.11.83.1232
22410.11.83.124/3010.11.83.125 to 10.11.83.12610.11.83.1272
22510.11.83.128/3010.11.83.129 to 10.11.83.13010.11.83.1312
22610.11.83.132/3010.11.83.133 to 10.11.83.13410.11.83.1352
22710.11.83.136/3010.11.83.137 to 10.11.83.13810.11.83.1392
22810.11.83.140/3010.11.83.141 to 10.11.83.14210.11.83.1432
22910.11.83.144/3010.11.83.145 to 10.11.83.14610.11.83.1472
23010.11.83.148/3010.11.83.149 to 10.11.83.15010.11.83.1512
23110.11.83.152/3010.11.83.153 to 10.11.83.15410.11.83.1552
23210.11.83.156/3010.11.83.157 to 10.11.83.15810.11.83.1592
23310.11.83.160/3010.11.83.161 to 10.11.83.16210.11.83.1632
23410.11.83.164/3010.11.83.165 to 10.11.83.16610.11.83.1672
23510.11.83.168/3010.11.83.169 to 10.11.83.17010.11.83.1712
23610.11.83.172/3010.11.83.173 to 10.11.83.17410.11.83.1752
23710.11.83.176/3010.11.83.177 to 10.11.83.17810.11.83.1792
23810.11.83.180/3010.11.83.181 to 10.11.83.18210.11.83.1832
23910.11.83.184/3010.11.83.185 to 10.11.83.18610.11.83.1872
24010.11.83.188/3010.11.83.189 to 10.11.83.19010.11.83.1912
24110.11.83.192/3010.11.83.193 to 10.11.83.19410.11.83.1952
24210.11.83.196/3010.11.83.197 to 10.11.83.19810.11.83.1992
24310.11.83.200/3010.11.83.201 to 10.11.83.20210.11.83.2032
24410.11.83.204/3010.11.83.205 to 10.11.83.20610.11.83.2072
24510.11.83.208/3010.11.83.209 to 10.11.83.21010.11.83.2112
24610.11.83.212/3010.11.83.213 to 10.11.83.21410.11.83.2152
24710.11.83.216/3010.11.83.217 to 10.11.83.21810.11.83.2192
24810.11.83.220/3010.11.83.221 to 10.11.83.22210.11.83.2232
24910.11.83.224/3010.11.83.225 to 10.11.83.22610.11.83.2272
25010.11.83.228/3010.11.83.229 to 10.11.83.23010.11.83.2312
25110.11.83.232/3010.11.83.233 to 10.11.83.23410.11.83.2352
25210.11.83.236/3010.11.83.237 to 10.11.83.23810.11.83.2392
25310.11.83.240/3010.11.83.241 to 10.11.83.24210.11.83.2432
25410.11.83.244/3010.11.83.245 to 10.11.83.24610.11.83.2472
25510.11.83.248/3010.11.83.249 to 10.11.83.25010.11.83.2512
25610.11.83.252/3010.11.83.253 to 10.11.83.25410.11.83.2552

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.