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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.

Network97.2.64.0/19
Usable hosts8,190
Subnet mask255.255.224.0
Addresses8,192
Network address
97.2.64.0
Broadcast address
97.2.95.255
First usable
97.2.64.1
Last usable
97.2.95.254
Usable hosts
8,190 (8,192 less the network and broadcast addresses)
Subnet mask
255.255.224.0
Wildcard mask
0.0.31.255 (Cisco ACLs, OSPF)
Prefix length
/19
Type
Public public
Old class
A (default /8)
As numbers
Hex 61024000 · Integer 1627537408 to 1627545599
Reverse DNS zones
64.2.97.in-addr.arpa
65.2.97.in-addr.arpa
66.2.97.in-addr.arpa
67.2.97.in-addr.arpa
68.2.97.in-addr.arpa
69.2.97.in-addr.arpa
70.2.97.in-addr.arpa
71.2.97.in-addr.arpa
72.2.97.in-addr.arpa
73.2.97.in-addr.arpa
74.2.97.in-addr.arpa
75.2.97.in-addr.arpa
76.2.97.in-addr.arpa
77.2.97.in-addr.arpa
78.2.97.in-addr.arpa
79.2.97.in-addr.arpa
and 16 more
/19 is not on a 8-bit boundary, so it takes 32 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01100001.00000010.01000000.0000000097.2.64.0
Subnet mask11111111.11111111.11100000.00000000255.255.224.0
Network01100001.00000010.01000000.0000000097.2.64.0
Broadcast01100001.00000010.01011111.1111111197.2.95.255
Split into smaller subnets/28
/20 (2)/21 (4)/22 (8)/23 (16)/24 (32)/25 (64)/26 (128)/27 (256)/28 (512)/29 (1,024)/30 (2,048)/31 (4,096)

97.2.64.0/19 makes 512 subnets of /28; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
197.2.64.0/2897.2.64.1 to 97.2.64.1497.2.64.1514
297.2.64.16/2897.2.64.17 to 97.2.64.3097.2.64.3114
397.2.64.32/2897.2.64.33 to 97.2.64.4697.2.64.4714
497.2.64.48/2897.2.64.49 to 97.2.64.6297.2.64.6314
597.2.64.64/2897.2.64.65 to 97.2.64.7897.2.64.7914
697.2.64.80/2897.2.64.81 to 97.2.64.9497.2.64.9514
797.2.64.96/2897.2.64.97 to 97.2.64.11097.2.64.11114
897.2.64.112/2897.2.64.113 to 97.2.64.12697.2.64.12714
997.2.64.128/2897.2.64.129 to 97.2.64.14297.2.64.14314
1097.2.64.144/2897.2.64.145 to 97.2.64.15897.2.64.15914
1197.2.64.160/2897.2.64.161 to 97.2.64.17497.2.64.17514
1297.2.64.176/2897.2.64.177 to 97.2.64.19097.2.64.19114
1397.2.64.192/2897.2.64.193 to 97.2.64.20697.2.64.20714
1497.2.64.208/2897.2.64.209 to 97.2.64.22297.2.64.22314
1597.2.64.224/2897.2.64.225 to 97.2.64.23897.2.64.23914
1697.2.64.240/2897.2.64.241 to 97.2.64.25497.2.64.25514
1797.2.65.0/2897.2.65.1 to 97.2.65.1497.2.65.1514
1897.2.65.16/2897.2.65.17 to 97.2.65.3097.2.65.3114
1997.2.65.32/2897.2.65.33 to 97.2.65.4697.2.65.4714
2097.2.65.48/2897.2.65.49 to 97.2.65.6297.2.65.6314
2197.2.65.64/2897.2.65.65 to 97.2.65.7897.2.65.7914
2297.2.65.80/2897.2.65.81 to 97.2.65.9497.2.65.9514
2397.2.65.96/2897.2.65.97 to 97.2.65.11097.2.65.11114
2497.2.65.112/2897.2.65.113 to 97.2.65.12697.2.65.12714
2597.2.65.128/2897.2.65.129 to 97.2.65.14297.2.65.14314
2697.2.65.144/2897.2.65.145 to 97.2.65.15897.2.65.15914
2797.2.65.160/2897.2.65.161 to 97.2.65.17497.2.65.17514
2897.2.65.176/2897.2.65.177 to 97.2.65.19097.2.65.19114
2997.2.65.192/2897.2.65.193 to 97.2.65.20697.2.65.20714
3097.2.65.208/2897.2.65.209 to 97.2.65.22297.2.65.22314
3197.2.65.224/2897.2.65.225 to 97.2.65.23897.2.65.23914
3297.2.65.240/2897.2.65.241 to 97.2.65.25497.2.65.25514
3397.2.66.0/2897.2.66.1 to 97.2.66.1497.2.66.1514
3497.2.66.16/2897.2.66.17 to 97.2.66.3097.2.66.3114
3597.2.66.32/2897.2.66.33 to 97.2.66.4697.2.66.4714
3697.2.66.48/2897.2.66.49 to 97.2.66.6297.2.66.6314
3797.2.66.64/2897.2.66.65 to 97.2.66.7897.2.66.7914
3897.2.66.80/2897.2.66.81 to 97.2.66.9497.2.66.9514
3997.2.66.96/2897.2.66.97 to 97.2.66.11097.2.66.11114
4097.2.66.112/2897.2.66.113 to 97.2.66.12697.2.66.12714
4197.2.66.128/2897.2.66.129 to 97.2.66.14297.2.66.14314
4297.2.66.144/2897.2.66.145 to 97.2.66.15897.2.66.15914
4397.2.66.160/2897.2.66.161 to 97.2.66.17497.2.66.17514
4497.2.66.176/2897.2.66.177 to 97.2.66.19097.2.66.19114
4597.2.66.192/2897.2.66.193 to 97.2.66.20697.2.66.20714
4697.2.66.208/2897.2.66.209 to 97.2.66.22297.2.66.22314
4797.2.66.224/2897.2.66.225 to 97.2.66.23897.2.66.23914
4897.2.66.240/2897.2.66.241 to 97.2.66.25497.2.66.25514
4997.2.67.0/2897.2.67.1 to 97.2.67.1497.2.67.1514
5097.2.67.16/2897.2.67.17 to 97.2.67.3097.2.67.3114
5197.2.67.32/2897.2.67.33 to 97.2.67.4697.2.67.4714
5297.2.67.48/2897.2.67.49 to 97.2.67.6297.2.67.6314
5397.2.67.64/2897.2.67.65 to 97.2.67.7897.2.67.7914
5497.2.67.80/2897.2.67.81 to 97.2.67.9497.2.67.9514
5597.2.67.96/2897.2.67.97 to 97.2.67.11097.2.67.11114
5697.2.67.112/2897.2.67.113 to 97.2.67.12697.2.67.12714
5797.2.67.128/2897.2.67.129 to 97.2.67.14297.2.67.14314
5897.2.67.144/2897.2.67.145 to 97.2.67.15897.2.67.15914
5997.2.67.160/2897.2.67.161 to 97.2.67.17497.2.67.17514
6097.2.67.176/2897.2.67.177 to 97.2.67.19097.2.67.19114
6197.2.67.192/2897.2.67.193 to 97.2.67.20697.2.67.20714
6297.2.67.208/2897.2.67.209 to 97.2.67.22297.2.67.22314
6397.2.67.224/2897.2.67.225 to 97.2.67.23897.2.67.23914
6497.2.67.240/2897.2.67.241 to 97.2.67.25497.2.67.25514
6597.2.68.0/2897.2.68.1 to 97.2.68.1497.2.68.1514
6697.2.68.16/2897.2.68.17 to 97.2.68.3097.2.68.3114
6797.2.68.32/2897.2.68.33 to 97.2.68.4697.2.68.4714
6897.2.68.48/2897.2.68.49 to 97.2.68.6297.2.68.6314
6997.2.68.64/2897.2.68.65 to 97.2.68.7897.2.68.7914
7097.2.68.80/2897.2.68.81 to 97.2.68.9497.2.68.9514
7197.2.68.96/2897.2.68.97 to 97.2.68.11097.2.68.11114
7297.2.68.112/2897.2.68.113 to 97.2.68.12697.2.68.12714
7397.2.68.128/2897.2.68.129 to 97.2.68.14297.2.68.14314
7497.2.68.144/2897.2.68.145 to 97.2.68.15897.2.68.15914
7597.2.68.160/2897.2.68.161 to 97.2.68.17497.2.68.17514
7697.2.68.176/2897.2.68.177 to 97.2.68.19097.2.68.19114
7797.2.68.192/2897.2.68.193 to 97.2.68.20697.2.68.20714
7897.2.68.208/2897.2.68.209 to 97.2.68.22297.2.68.22314
7997.2.68.224/2897.2.68.225 to 97.2.68.23897.2.68.23914
8097.2.68.240/2897.2.68.241 to 97.2.68.25497.2.68.25514
8197.2.69.0/2897.2.69.1 to 97.2.69.1497.2.69.1514
8297.2.69.16/2897.2.69.17 to 97.2.69.3097.2.69.3114
8397.2.69.32/2897.2.69.33 to 97.2.69.4697.2.69.4714
8497.2.69.48/2897.2.69.49 to 97.2.69.6297.2.69.6314
8597.2.69.64/2897.2.69.65 to 97.2.69.7897.2.69.7914
8697.2.69.80/2897.2.69.81 to 97.2.69.9497.2.69.9514
8797.2.69.96/2897.2.69.97 to 97.2.69.11097.2.69.11114
8897.2.69.112/2897.2.69.113 to 97.2.69.12697.2.69.12714
8997.2.69.128/2897.2.69.129 to 97.2.69.14297.2.69.14314
9097.2.69.144/2897.2.69.145 to 97.2.69.15897.2.69.15914
9197.2.69.160/2897.2.69.161 to 97.2.69.17497.2.69.17514
9297.2.69.176/2897.2.69.177 to 97.2.69.19097.2.69.19114
9397.2.69.192/2897.2.69.193 to 97.2.69.20697.2.69.20714
9497.2.69.208/2897.2.69.209 to 97.2.69.22297.2.69.22314
9597.2.69.224/2897.2.69.225 to 97.2.69.23897.2.69.23914
9697.2.69.240/2897.2.69.241 to 97.2.69.25497.2.69.25514
9797.2.70.0/2897.2.70.1 to 97.2.70.1497.2.70.1514
9897.2.70.16/2897.2.70.17 to 97.2.70.3097.2.70.3114
9997.2.70.32/2897.2.70.33 to 97.2.70.4697.2.70.4714
10097.2.70.48/2897.2.70.49 to 97.2.70.6297.2.70.6314
10197.2.70.64/2897.2.70.65 to 97.2.70.7897.2.70.7914
10297.2.70.80/2897.2.70.81 to 97.2.70.9497.2.70.9514
10397.2.70.96/2897.2.70.97 to 97.2.70.11097.2.70.11114
10497.2.70.112/2897.2.70.113 to 97.2.70.12697.2.70.12714
10597.2.70.128/2897.2.70.129 to 97.2.70.14297.2.70.14314
10697.2.70.144/2897.2.70.145 to 97.2.70.15897.2.70.15914
10797.2.70.160/2897.2.70.161 to 97.2.70.17497.2.70.17514
10897.2.70.176/2897.2.70.177 to 97.2.70.19097.2.70.19114
10997.2.70.192/2897.2.70.193 to 97.2.70.20697.2.70.20714
11097.2.70.208/2897.2.70.209 to 97.2.70.22297.2.70.22314
11197.2.70.224/2897.2.70.225 to 97.2.70.23897.2.70.23914
11297.2.70.240/2897.2.70.241 to 97.2.70.25497.2.70.25514
11397.2.71.0/2897.2.71.1 to 97.2.71.1497.2.71.1514
11497.2.71.16/2897.2.71.17 to 97.2.71.3097.2.71.3114
11597.2.71.32/2897.2.71.33 to 97.2.71.4697.2.71.4714
11697.2.71.48/2897.2.71.49 to 97.2.71.6297.2.71.6314
11797.2.71.64/2897.2.71.65 to 97.2.71.7897.2.71.7914
11897.2.71.80/2897.2.71.81 to 97.2.71.9497.2.71.9514
11997.2.71.96/2897.2.71.97 to 97.2.71.11097.2.71.11114
12097.2.71.112/2897.2.71.113 to 97.2.71.12697.2.71.12714
12197.2.71.128/2897.2.71.129 to 97.2.71.14297.2.71.14314
12297.2.71.144/2897.2.71.145 to 97.2.71.15897.2.71.15914
12397.2.71.160/2897.2.71.161 to 97.2.71.17497.2.71.17514
12497.2.71.176/2897.2.71.177 to 97.2.71.19097.2.71.19114
12597.2.71.192/2897.2.71.193 to 97.2.71.20697.2.71.20714
12697.2.71.208/2897.2.71.209 to 97.2.71.22297.2.71.22314
12797.2.71.224/2897.2.71.225 to 97.2.71.23897.2.71.23914
12897.2.71.240/2897.2.71.241 to 97.2.71.25497.2.71.25514
12997.2.72.0/2897.2.72.1 to 97.2.72.1497.2.72.1514
13097.2.72.16/2897.2.72.17 to 97.2.72.3097.2.72.3114
13197.2.72.32/2897.2.72.33 to 97.2.72.4697.2.72.4714
13297.2.72.48/2897.2.72.49 to 97.2.72.6297.2.72.6314
13397.2.72.64/2897.2.72.65 to 97.2.72.7897.2.72.7914
13497.2.72.80/2897.2.72.81 to 97.2.72.9497.2.72.9514
13597.2.72.96/2897.2.72.97 to 97.2.72.11097.2.72.11114
13697.2.72.112/2897.2.72.113 to 97.2.72.12697.2.72.12714
13797.2.72.128/2897.2.72.129 to 97.2.72.14297.2.72.14314
13897.2.72.144/2897.2.72.145 to 97.2.72.15897.2.72.15914
13997.2.72.160/2897.2.72.161 to 97.2.72.17497.2.72.17514
14097.2.72.176/2897.2.72.177 to 97.2.72.19097.2.72.19114
14197.2.72.192/2897.2.72.193 to 97.2.72.20697.2.72.20714
14297.2.72.208/2897.2.72.209 to 97.2.72.22297.2.72.22314
14397.2.72.224/2897.2.72.225 to 97.2.72.23897.2.72.23914
14497.2.72.240/2897.2.72.241 to 97.2.72.25497.2.72.25514
14597.2.73.0/2897.2.73.1 to 97.2.73.1497.2.73.1514
14697.2.73.16/2897.2.73.17 to 97.2.73.3097.2.73.3114
14797.2.73.32/2897.2.73.33 to 97.2.73.4697.2.73.4714
14897.2.73.48/2897.2.73.49 to 97.2.73.6297.2.73.6314
14997.2.73.64/2897.2.73.65 to 97.2.73.7897.2.73.7914
15097.2.73.80/2897.2.73.81 to 97.2.73.9497.2.73.9514
15197.2.73.96/2897.2.73.97 to 97.2.73.11097.2.73.11114
15297.2.73.112/2897.2.73.113 to 97.2.73.12697.2.73.12714
15397.2.73.128/2897.2.73.129 to 97.2.73.14297.2.73.14314
15497.2.73.144/2897.2.73.145 to 97.2.73.15897.2.73.15914
15597.2.73.160/2897.2.73.161 to 97.2.73.17497.2.73.17514
15697.2.73.176/2897.2.73.177 to 97.2.73.19097.2.73.19114
15797.2.73.192/2897.2.73.193 to 97.2.73.20697.2.73.20714
15897.2.73.208/2897.2.73.209 to 97.2.73.22297.2.73.22314
15997.2.73.224/2897.2.73.225 to 97.2.73.23897.2.73.23914
16097.2.73.240/2897.2.73.241 to 97.2.73.25497.2.73.25514
16197.2.74.0/2897.2.74.1 to 97.2.74.1497.2.74.1514
16297.2.74.16/2897.2.74.17 to 97.2.74.3097.2.74.3114
16397.2.74.32/2897.2.74.33 to 97.2.74.4697.2.74.4714
16497.2.74.48/2897.2.74.49 to 97.2.74.6297.2.74.6314
16597.2.74.64/2897.2.74.65 to 97.2.74.7897.2.74.7914
16697.2.74.80/2897.2.74.81 to 97.2.74.9497.2.74.9514
16797.2.74.96/2897.2.74.97 to 97.2.74.11097.2.74.11114
16897.2.74.112/2897.2.74.113 to 97.2.74.12697.2.74.12714
16997.2.74.128/2897.2.74.129 to 97.2.74.14297.2.74.14314
17097.2.74.144/2897.2.74.145 to 97.2.74.15897.2.74.15914
17197.2.74.160/2897.2.74.161 to 97.2.74.17497.2.74.17514
17297.2.74.176/2897.2.74.177 to 97.2.74.19097.2.74.19114
17397.2.74.192/2897.2.74.193 to 97.2.74.20697.2.74.20714
17497.2.74.208/2897.2.74.209 to 97.2.74.22297.2.74.22314
17597.2.74.224/2897.2.74.225 to 97.2.74.23897.2.74.23914
17697.2.74.240/2897.2.74.241 to 97.2.74.25497.2.74.25514
17797.2.75.0/2897.2.75.1 to 97.2.75.1497.2.75.1514
17897.2.75.16/2897.2.75.17 to 97.2.75.3097.2.75.3114
17997.2.75.32/2897.2.75.33 to 97.2.75.4697.2.75.4714
18097.2.75.48/2897.2.75.49 to 97.2.75.6297.2.75.6314
18197.2.75.64/2897.2.75.65 to 97.2.75.7897.2.75.7914
18297.2.75.80/2897.2.75.81 to 97.2.75.9497.2.75.9514
18397.2.75.96/2897.2.75.97 to 97.2.75.11097.2.75.11114
18497.2.75.112/2897.2.75.113 to 97.2.75.12697.2.75.12714
18597.2.75.128/2897.2.75.129 to 97.2.75.14297.2.75.14314
18697.2.75.144/2897.2.75.145 to 97.2.75.15897.2.75.15914
18797.2.75.160/2897.2.75.161 to 97.2.75.17497.2.75.17514
18897.2.75.176/2897.2.75.177 to 97.2.75.19097.2.75.19114
18997.2.75.192/2897.2.75.193 to 97.2.75.20697.2.75.20714
19097.2.75.208/2897.2.75.209 to 97.2.75.22297.2.75.22314
19197.2.75.224/2897.2.75.225 to 97.2.75.23897.2.75.23914
19297.2.75.240/2897.2.75.241 to 97.2.75.25497.2.75.25514
19397.2.76.0/2897.2.76.1 to 97.2.76.1497.2.76.1514
19497.2.76.16/2897.2.76.17 to 97.2.76.3097.2.76.3114
19597.2.76.32/2897.2.76.33 to 97.2.76.4697.2.76.4714
19697.2.76.48/2897.2.76.49 to 97.2.76.6297.2.76.6314
19797.2.76.64/2897.2.76.65 to 97.2.76.7897.2.76.7914
19897.2.76.80/2897.2.76.81 to 97.2.76.9497.2.76.9514
19997.2.76.96/2897.2.76.97 to 97.2.76.11097.2.76.11114
20097.2.76.112/2897.2.76.113 to 97.2.76.12697.2.76.12714
20197.2.76.128/2897.2.76.129 to 97.2.76.14297.2.76.14314
20297.2.76.144/2897.2.76.145 to 97.2.76.15897.2.76.15914
20397.2.76.160/2897.2.76.161 to 97.2.76.17497.2.76.17514
20497.2.76.176/2897.2.76.177 to 97.2.76.19097.2.76.19114
20597.2.76.192/2897.2.76.193 to 97.2.76.20697.2.76.20714
20697.2.76.208/2897.2.76.209 to 97.2.76.22297.2.76.22314
20797.2.76.224/2897.2.76.225 to 97.2.76.23897.2.76.23914
20897.2.76.240/2897.2.76.241 to 97.2.76.25497.2.76.25514
20997.2.77.0/2897.2.77.1 to 97.2.77.1497.2.77.1514
21097.2.77.16/2897.2.77.17 to 97.2.77.3097.2.77.3114
21197.2.77.32/2897.2.77.33 to 97.2.77.4697.2.77.4714
21297.2.77.48/2897.2.77.49 to 97.2.77.6297.2.77.6314
21397.2.77.64/2897.2.77.65 to 97.2.77.7897.2.77.7914
21497.2.77.80/2897.2.77.81 to 97.2.77.9497.2.77.9514
21597.2.77.96/2897.2.77.97 to 97.2.77.11097.2.77.11114
21697.2.77.112/2897.2.77.113 to 97.2.77.12697.2.77.12714
21797.2.77.128/2897.2.77.129 to 97.2.77.14297.2.77.14314
21897.2.77.144/2897.2.77.145 to 97.2.77.15897.2.77.15914
21997.2.77.160/2897.2.77.161 to 97.2.77.17497.2.77.17514
22097.2.77.176/2897.2.77.177 to 97.2.77.19097.2.77.19114
22197.2.77.192/2897.2.77.193 to 97.2.77.20697.2.77.20714
22297.2.77.208/2897.2.77.209 to 97.2.77.22297.2.77.22314
22397.2.77.224/2897.2.77.225 to 97.2.77.23897.2.77.23914
22497.2.77.240/2897.2.77.241 to 97.2.77.25497.2.77.25514
22597.2.78.0/2897.2.78.1 to 97.2.78.1497.2.78.1514
22697.2.78.16/2897.2.78.17 to 97.2.78.3097.2.78.3114
22797.2.78.32/2897.2.78.33 to 97.2.78.4697.2.78.4714
22897.2.78.48/2897.2.78.49 to 97.2.78.6297.2.78.6314
22997.2.78.64/2897.2.78.65 to 97.2.78.7897.2.78.7914
23097.2.78.80/2897.2.78.81 to 97.2.78.9497.2.78.9514
23197.2.78.96/2897.2.78.97 to 97.2.78.11097.2.78.11114
23297.2.78.112/2897.2.78.113 to 97.2.78.12697.2.78.12714
23397.2.78.128/2897.2.78.129 to 97.2.78.14297.2.78.14314
23497.2.78.144/2897.2.78.145 to 97.2.78.15897.2.78.15914
23597.2.78.160/2897.2.78.161 to 97.2.78.17497.2.78.17514
23697.2.78.176/2897.2.78.177 to 97.2.78.19097.2.78.19114
23797.2.78.192/2897.2.78.193 to 97.2.78.20697.2.78.20714
23897.2.78.208/2897.2.78.209 to 97.2.78.22297.2.78.22314
23997.2.78.224/2897.2.78.225 to 97.2.78.23897.2.78.23914
24097.2.78.240/2897.2.78.241 to 97.2.78.25497.2.78.25514
24197.2.79.0/2897.2.79.1 to 97.2.79.1497.2.79.1514
24297.2.79.16/2897.2.79.17 to 97.2.79.3097.2.79.3114
24397.2.79.32/2897.2.79.33 to 97.2.79.4697.2.79.4714
24497.2.79.48/2897.2.79.49 to 97.2.79.6297.2.79.6314
24597.2.79.64/2897.2.79.65 to 97.2.79.7897.2.79.7914
24697.2.79.80/2897.2.79.81 to 97.2.79.9497.2.79.9514
24797.2.79.96/2897.2.79.97 to 97.2.79.11097.2.79.11114
24897.2.79.112/2897.2.79.113 to 97.2.79.12697.2.79.12714
24997.2.79.128/2897.2.79.129 to 97.2.79.14297.2.79.14314
25097.2.79.144/2897.2.79.145 to 97.2.79.15897.2.79.15914
25197.2.79.160/2897.2.79.161 to 97.2.79.17497.2.79.17514
25297.2.79.176/2897.2.79.177 to 97.2.79.19097.2.79.19114
25397.2.79.192/2897.2.79.193 to 97.2.79.20697.2.79.20714
25497.2.79.208/2897.2.79.209 to 97.2.79.22297.2.79.22314
25597.2.79.224/2897.2.79.225 to 97.2.79.23897.2.79.23914
25697.2.79.240/2897.2.79.241 to 97.2.79.25497.2.79.25514

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.