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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.

Network87.30.64.0/19
Usable hosts8,190
Subnet mask255.255.224.0
Addresses8,192
Network address
87.30.64.0
Broadcast address
87.30.95.255
First usable
87.30.64.1
Last usable
87.30.95.254
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 571E4000 · Integer 1461600256 to 1461608447
Reverse DNS zones
64.30.87.in-addr.arpa
65.30.87.in-addr.arpa
66.30.87.in-addr.arpa
67.30.87.in-addr.arpa
68.30.87.in-addr.arpa
69.30.87.in-addr.arpa
70.30.87.in-addr.arpa
71.30.87.in-addr.arpa
72.30.87.in-addr.arpa
73.30.87.in-addr.arpa
74.30.87.in-addr.arpa
75.30.87.in-addr.arpa
76.30.87.in-addr.arpa
77.30.87.in-addr.arpa
78.30.87.in-addr.arpa
79.30.87.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
Address01010111.00011110.01000000.0000000087.30.64.0
Subnet mask11111111.11111111.11100000.00000000255.255.224.0
Network01010111.00011110.01000000.0000000087.30.64.0
Broadcast01010111.00011110.01011111.1111111187.30.95.255
Split into smaller subnets/27
/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)

87.30.64.0/19 makes 256 subnets of /27.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
187.30.64.0/2787.30.64.1 to 87.30.64.3087.30.64.3130
287.30.64.32/2787.30.64.33 to 87.30.64.6287.30.64.6330
387.30.64.64/2787.30.64.65 to 87.30.64.9487.30.64.9530
487.30.64.96/2787.30.64.97 to 87.30.64.12687.30.64.12730
587.30.64.128/2787.30.64.129 to 87.30.64.15887.30.64.15930
687.30.64.160/2787.30.64.161 to 87.30.64.19087.30.64.19130
787.30.64.192/2787.30.64.193 to 87.30.64.22287.30.64.22330
887.30.64.224/2787.30.64.225 to 87.30.64.25487.30.64.25530
987.30.65.0/2787.30.65.1 to 87.30.65.3087.30.65.3130
1087.30.65.32/2787.30.65.33 to 87.30.65.6287.30.65.6330
1187.30.65.64/2787.30.65.65 to 87.30.65.9487.30.65.9530
1287.30.65.96/2787.30.65.97 to 87.30.65.12687.30.65.12730
1387.30.65.128/2787.30.65.129 to 87.30.65.15887.30.65.15930
1487.30.65.160/2787.30.65.161 to 87.30.65.19087.30.65.19130
1587.30.65.192/2787.30.65.193 to 87.30.65.22287.30.65.22330
1687.30.65.224/2787.30.65.225 to 87.30.65.25487.30.65.25530
1787.30.66.0/2787.30.66.1 to 87.30.66.3087.30.66.3130
1887.30.66.32/2787.30.66.33 to 87.30.66.6287.30.66.6330
1987.30.66.64/2787.30.66.65 to 87.30.66.9487.30.66.9530
2087.30.66.96/2787.30.66.97 to 87.30.66.12687.30.66.12730
2187.30.66.128/2787.30.66.129 to 87.30.66.15887.30.66.15930
2287.30.66.160/2787.30.66.161 to 87.30.66.19087.30.66.19130
2387.30.66.192/2787.30.66.193 to 87.30.66.22287.30.66.22330
2487.30.66.224/2787.30.66.225 to 87.30.66.25487.30.66.25530
2587.30.67.0/2787.30.67.1 to 87.30.67.3087.30.67.3130
2687.30.67.32/2787.30.67.33 to 87.30.67.6287.30.67.6330
2787.30.67.64/2787.30.67.65 to 87.30.67.9487.30.67.9530
2887.30.67.96/2787.30.67.97 to 87.30.67.12687.30.67.12730
2987.30.67.128/2787.30.67.129 to 87.30.67.15887.30.67.15930
3087.30.67.160/2787.30.67.161 to 87.30.67.19087.30.67.19130
3187.30.67.192/2787.30.67.193 to 87.30.67.22287.30.67.22330
3287.30.67.224/2787.30.67.225 to 87.30.67.25487.30.67.25530
3387.30.68.0/2787.30.68.1 to 87.30.68.3087.30.68.3130
3487.30.68.32/2787.30.68.33 to 87.30.68.6287.30.68.6330
3587.30.68.64/2787.30.68.65 to 87.30.68.9487.30.68.9530
3687.30.68.96/2787.30.68.97 to 87.30.68.12687.30.68.12730
3787.30.68.128/2787.30.68.129 to 87.30.68.15887.30.68.15930
3887.30.68.160/2787.30.68.161 to 87.30.68.19087.30.68.19130
3987.30.68.192/2787.30.68.193 to 87.30.68.22287.30.68.22330
4087.30.68.224/2787.30.68.225 to 87.30.68.25487.30.68.25530
4187.30.69.0/2787.30.69.1 to 87.30.69.3087.30.69.3130
4287.30.69.32/2787.30.69.33 to 87.30.69.6287.30.69.6330
4387.30.69.64/2787.30.69.65 to 87.30.69.9487.30.69.9530
4487.30.69.96/2787.30.69.97 to 87.30.69.12687.30.69.12730
4587.30.69.128/2787.30.69.129 to 87.30.69.15887.30.69.15930
4687.30.69.160/2787.30.69.161 to 87.30.69.19087.30.69.19130
4787.30.69.192/2787.30.69.193 to 87.30.69.22287.30.69.22330
4887.30.69.224/2787.30.69.225 to 87.30.69.25487.30.69.25530
4987.30.70.0/2787.30.70.1 to 87.30.70.3087.30.70.3130
5087.30.70.32/2787.30.70.33 to 87.30.70.6287.30.70.6330
5187.30.70.64/2787.30.70.65 to 87.30.70.9487.30.70.9530
5287.30.70.96/2787.30.70.97 to 87.30.70.12687.30.70.12730
5387.30.70.128/2787.30.70.129 to 87.30.70.15887.30.70.15930
5487.30.70.160/2787.30.70.161 to 87.30.70.19087.30.70.19130
5587.30.70.192/2787.30.70.193 to 87.30.70.22287.30.70.22330
5687.30.70.224/2787.30.70.225 to 87.30.70.25487.30.70.25530
5787.30.71.0/2787.30.71.1 to 87.30.71.3087.30.71.3130
5887.30.71.32/2787.30.71.33 to 87.30.71.6287.30.71.6330
5987.30.71.64/2787.30.71.65 to 87.30.71.9487.30.71.9530
6087.30.71.96/2787.30.71.97 to 87.30.71.12687.30.71.12730
6187.30.71.128/2787.30.71.129 to 87.30.71.15887.30.71.15930
6287.30.71.160/2787.30.71.161 to 87.30.71.19087.30.71.19130
6387.30.71.192/2787.30.71.193 to 87.30.71.22287.30.71.22330
6487.30.71.224/2787.30.71.225 to 87.30.71.25487.30.71.25530
6587.30.72.0/2787.30.72.1 to 87.30.72.3087.30.72.3130
6687.30.72.32/2787.30.72.33 to 87.30.72.6287.30.72.6330
6787.30.72.64/2787.30.72.65 to 87.30.72.9487.30.72.9530
6887.30.72.96/2787.30.72.97 to 87.30.72.12687.30.72.12730
6987.30.72.128/2787.30.72.129 to 87.30.72.15887.30.72.15930
7087.30.72.160/2787.30.72.161 to 87.30.72.19087.30.72.19130
7187.30.72.192/2787.30.72.193 to 87.30.72.22287.30.72.22330
7287.30.72.224/2787.30.72.225 to 87.30.72.25487.30.72.25530
7387.30.73.0/2787.30.73.1 to 87.30.73.3087.30.73.3130
7487.30.73.32/2787.30.73.33 to 87.30.73.6287.30.73.6330
7587.30.73.64/2787.30.73.65 to 87.30.73.9487.30.73.9530
7687.30.73.96/2787.30.73.97 to 87.30.73.12687.30.73.12730
7787.30.73.128/2787.30.73.129 to 87.30.73.15887.30.73.15930
7887.30.73.160/2787.30.73.161 to 87.30.73.19087.30.73.19130
7987.30.73.192/2787.30.73.193 to 87.30.73.22287.30.73.22330
8087.30.73.224/2787.30.73.225 to 87.30.73.25487.30.73.25530
8187.30.74.0/2787.30.74.1 to 87.30.74.3087.30.74.3130
8287.30.74.32/2787.30.74.33 to 87.30.74.6287.30.74.6330
8387.30.74.64/2787.30.74.65 to 87.30.74.9487.30.74.9530
8487.30.74.96/2787.30.74.97 to 87.30.74.12687.30.74.12730
8587.30.74.128/2787.30.74.129 to 87.30.74.15887.30.74.15930
8687.30.74.160/2787.30.74.161 to 87.30.74.19087.30.74.19130
8787.30.74.192/2787.30.74.193 to 87.30.74.22287.30.74.22330
8887.30.74.224/2787.30.74.225 to 87.30.74.25487.30.74.25530
8987.30.75.0/2787.30.75.1 to 87.30.75.3087.30.75.3130
9087.30.75.32/2787.30.75.33 to 87.30.75.6287.30.75.6330
9187.30.75.64/2787.30.75.65 to 87.30.75.9487.30.75.9530
9287.30.75.96/2787.30.75.97 to 87.30.75.12687.30.75.12730
9387.30.75.128/2787.30.75.129 to 87.30.75.15887.30.75.15930
9487.30.75.160/2787.30.75.161 to 87.30.75.19087.30.75.19130
9587.30.75.192/2787.30.75.193 to 87.30.75.22287.30.75.22330
9687.30.75.224/2787.30.75.225 to 87.30.75.25487.30.75.25530
9787.30.76.0/2787.30.76.1 to 87.30.76.3087.30.76.3130
9887.30.76.32/2787.30.76.33 to 87.30.76.6287.30.76.6330
9987.30.76.64/2787.30.76.65 to 87.30.76.9487.30.76.9530
10087.30.76.96/2787.30.76.97 to 87.30.76.12687.30.76.12730
10187.30.76.128/2787.30.76.129 to 87.30.76.15887.30.76.15930
10287.30.76.160/2787.30.76.161 to 87.30.76.19087.30.76.19130
10387.30.76.192/2787.30.76.193 to 87.30.76.22287.30.76.22330
10487.30.76.224/2787.30.76.225 to 87.30.76.25487.30.76.25530
10587.30.77.0/2787.30.77.1 to 87.30.77.3087.30.77.3130
10687.30.77.32/2787.30.77.33 to 87.30.77.6287.30.77.6330
10787.30.77.64/2787.30.77.65 to 87.30.77.9487.30.77.9530
10887.30.77.96/2787.30.77.97 to 87.30.77.12687.30.77.12730
10987.30.77.128/2787.30.77.129 to 87.30.77.15887.30.77.15930
11087.30.77.160/2787.30.77.161 to 87.30.77.19087.30.77.19130
11187.30.77.192/2787.30.77.193 to 87.30.77.22287.30.77.22330
11287.30.77.224/2787.30.77.225 to 87.30.77.25487.30.77.25530
11387.30.78.0/2787.30.78.1 to 87.30.78.3087.30.78.3130
11487.30.78.32/2787.30.78.33 to 87.30.78.6287.30.78.6330
11587.30.78.64/2787.30.78.65 to 87.30.78.9487.30.78.9530
11687.30.78.96/2787.30.78.97 to 87.30.78.12687.30.78.12730
11787.30.78.128/2787.30.78.129 to 87.30.78.15887.30.78.15930
11887.30.78.160/2787.30.78.161 to 87.30.78.19087.30.78.19130
11987.30.78.192/2787.30.78.193 to 87.30.78.22287.30.78.22330
12087.30.78.224/2787.30.78.225 to 87.30.78.25487.30.78.25530
12187.30.79.0/2787.30.79.1 to 87.30.79.3087.30.79.3130
12287.30.79.32/2787.30.79.33 to 87.30.79.6287.30.79.6330
12387.30.79.64/2787.30.79.65 to 87.30.79.9487.30.79.9530
12487.30.79.96/2787.30.79.97 to 87.30.79.12687.30.79.12730
12587.30.79.128/2787.30.79.129 to 87.30.79.15887.30.79.15930
12687.30.79.160/2787.30.79.161 to 87.30.79.19087.30.79.19130
12787.30.79.192/2787.30.79.193 to 87.30.79.22287.30.79.22330
12887.30.79.224/2787.30.79.225 to 87.30.79.25487.30.79.25530
12987.30.80.0/2787.30.80.1 to 87.30.80.3087.30.80.3130
13087.30.80.32/2787.30.80.33 to 87.30.80.6287.30.80.6330
13187.30.80.64/2787.30.80.65 to 87.30.80.9487.30.80.9530
13287.30.80.96/2787.30.80.97 to 87.30.80.12687.30.80.12730
13387.30.80.128/2787.30.80.129 to 87.30.80.15887.30.80.15930
13487.30.80.160/2787.30.80.161 to 87.30.80.19087.30.80.19130
13587.30.80.192/2787.30.80.193 to 87.30.80.22287.30.80.22330
13687.30.80.224/2787.30.80.225 to 87.30.80.25487.30.80.25530
13787.30.81.0/2787.30.81.1 to 87.30.81.3087.30.81.3130
13887.30.81.32/2787.30.81.33 to 87.30.81.6287.30.81.6330
13987.30.81.64/2787.30.81.65 to 87.30.81.9487.30.81.9530
14087.30.81.96/2787.30.81.97 to 87.30.81.12687.30.81.12730
14187.30.81.128/2787.30.81.129 to 87.30.81.15887.30.81.15930
14287.30.81.160/2787.30.81.161 to 87.30.81.19087.30.81.19130
14387.30.81.192/2787.30.81.193 to 87.30.81.22287.30.81.22330
14487.30.81.224/2787.30.81.225 to 87.30.81.25487.30.81.25530
14587.30.82.0/2787.30.82.1 to 87.30.82.3087.30.82.3130
14687.30.82.32/2787.30.82.33 to 87.30.82.6287.30.82.6330
14787.30.82.64/2787.30.82.65 to 87.30.82.9487.30.82.9530
14887.30.82.96/2787.30.82.97 to 87.30.82.12687.30.82.12730
14987.30.82.128/2787.30.82.129 to 87.30.82.15887.30.82.15930
15087.30.82.160/2787.30.82.161 to 87.30.82.19087.30.82.19130
15187.30.82.192/2787.30.82.193 to 87.30.82.22287.30.82.22330
15287.30.82.224/2787.30.82.225 to 87.30.82.25487.30.82.25530
15387.30.83.0/2787.30.83.1 to 87.30.83.3087.30.83.3130
15487.30.83.32/2787.30.83.33 to 87.30.83.6287.30.83.6330
15587.30.83.64/2787.30.83.65 to 87.30.83.9487.30.83.9530
15687.30.83.96/2787.30.83.97 to 87.30.83.12687.30.83.12730
15787.30.83.128/2787.30.83.129 to 87.30.83.15887.30.83.15930
15887.30.83.160/2787.30.83.161 to 87.30.83.19087.30.83.19130
15987.30.83.192/2787.30.83.193 to 87.30.83.22287.30.83.22330
16087.30.83.224/2787.30.83.225 to 87.30.83.25487.30.83.25530
16187.30.84.0/2787.30.84.1 to 87.30.84.3087.30.84.3130
16287.30.84.32/2787.30.84.33 to 87.30.84.6287.30.84.6330
16387.30.84.64/2787.30.84.65 to 87.30.84.9487.30.84.9530
16487.30.84.96/2787.30.84.97 to 87.30.84.12687.30.84.12730
16587.30.84.128/2787.30.84.129 to 87.30.84.15887.30.84.15930
16687.30.84.160/2787.30.84.161 to 87.30.84.19087.30.84.19130
16787.30.84.192/2787.30.84.193 to 87.30.84.22287.30.84.22330
16887.30.84.224/2787.30.84.225 to 87.30.84.25487.30.84.25530
16987.30.85.0/2787.30.85.1 to 87.30.85.3087.30.85.3130
17087.30.85.32/2787.30.85.33 to 87.30.85.6287.30.85.6330
17187.30.85.64/2787.30.85.65 to 87.30.85.9487.30.85.9530
17287.30.85.96/2787.30.85.97 to 87.30.85.12687.30.85.12730
17387.30.85.128/2787.30.85.129 to 87.30.85.15887.30.85.15930
17487.30.85.160/2787.30.85.161 to 87.30.85.19087.30.85.19130
17587.30.85.192/2787.30.85.193 to 87.30.85.22287.30.85.22330
17687.30.85.224/2787.30.85.225 to 87.30.85.25487.30.85.25530
17787.30.86.0/2787.30.86.1 to 87.30.86.3087.30.86.3130
17887.30.86.32/2787.30.86.33 to 87.30.86.6287.30.86.6330
17987.30.86.64/2787.30.86.65 to 87.30.86.9487.30.86.9530
18087.30.86.96/2787.30.86.97 to 87.30.86.12687.30.86.12730
18187.30.86.128/2787.30.86.129 to 87.30.86.15887.30.86.15930
18287.30.86.160/2787.30.86.161 to 87.30.86.19087.30.86.19130
18387.30.86.192/2787.30.86.193 to 87.30.86.22287.30.86.22330
18487.30.86.224/2787.30.86.225 to 87.30.86.25487.30.86.25530
18587.30.87.0/2787.30.87.1 to 87.30.87.3087.30.87.3130
18687.30.87.32/2787.30.87.33 to 87.30.87.6287.30.87.6330
18787.30.87.64/2787.30.87.65 to 87.30.87.9487.30.87.9530
18887.30.87.96/2787.30.87.97 to 87.30.87.12687.30.87.12730
18987.30.87.128/2787.30.87.129 to 87.30.87.15887.30.87.15930
19087.30.87.160/2787.30.87.161 to 87.30.87.19087.30.87.19130
19187.30.87.192/2787.30.87.193 to 87.30.87.22287.30.87.22330
19287.30.87.224/2787.30.87.225 to 87.30.87.25487.30.87.25530
19387.30.88.0/2787.30.88.1 to 87.30.88.3087.30.88.3130
19487.30.88.32/2787.30.88.33 to 87.30.88.6287.30.88.6330
19587.30.88.64/2787.30.88.65 to 87.30.88.9487.30.88.9530
19687.30.88.96/2787.30.88.97 to 87.30.88.12687.30.88.12730
19787.30.88.128/2787.30.88.129 to 87.30.88.15887.30.88.15930
19887.30.88.160/2787.30.88.161 to 87.30.88.19087.30.88.19130
19987.30.88.192/2787.30.88.193 to 87.30.88.22287.30.88.22330
20087.30.88.224/2787.30.88.225 to 87.30.88.25487.30.88.25530
20187.30.89.0/2787.30.89.1 to 87.30.89.3087.30.89.3130
20287.30.89.32/2787.30.89.33 to 87.30.89.6287.30.89.6330
20387.30.89.64/2787.30.89.65 to 87.30.89.9487.30.89.9530
20487.30.89.96/2787.30.89.97 to 87.30.89.12687.30.89.12730
20587.30.89.128/2787.30.89.129 to 87.30.89.15887.30.89.15930
20687.30.89.160/2787.30.89.161 to 87.30.89.19087.30.89.19130
20787.30.89.192/2787.30.89.193 to 87.30.89.22287.30.89.22330
20887.30.89.224/2787.30.89.225 to 87.30.89.25487.30.89.25530
20987.30.90.0/2787.30.90.1 to 87.30.90.3087.30.90.3130
21087.30.90.32/2787.30.90.33 to 87.30.90.6287.30.90.6330
21187.30.90.64/2787.30.90.65 to 87.30.90.9487.30.90.9530
21287.30.90.96/2787.30.90.97 to 87.30.90.12687.30.90.12730
21387.30.90.128/2787.30.90.129 to 87.30.90.15887.30.90.15930
21487.30.90.160/2787.30.90.161 to 87.30.90.19087.30.90.19130
21587.30.90.192/2787.30.90.193 to 87.30.90.22287.30.90.22330
21687.30.90.224/2787.30.90.225 to 87.30.90.25487.30.90.25530
21787.30.91.0/2787.30.91.1 to 87.30.91.3087.30.91.3130
21887.30.91.32/2787.30.91.33 to 87.30.91.6287.30.91.6330
21987.30.91.64/2787.30.91.65 to 87.30.91.9487.30.91.9530
22087.30.91.96/2787.30.91.97 to 87.30.91.12687.30.91.12730
22187.30.91.128/2787.30.91.129 to 87.30.91.15887.30.91.15930
22287.30.91.160/2787.30.91.161 to 87.30.91.19087.30.91.19130
22387.30.91.192/2787.30.91.193 to 87.30.91.22287.30.91.22330
22487.30.91.224/2787.30.91.225 to 87.30.91.25487.30.91.25530
22587.30.92.0/2787.30.92.1 to 87.30.92.3087.30.92.3130
22687.30.92.32/2787.30.92.33 to 87.30.92.6287.30.92.6330
22787.30.92.64/2787.30.92.65 to 87.30.92.9487.30.92.9530
22887.30.92.96/2787.30.92.97 to 87.30.92.12687.30.92.12730
22987.30.92.128/2787.30.92.129 to 87.30.92.15887.30.92.15930
23087.30.92.160/2787.30.92.161 to 87.30.92.19087.30.92.19130
23187.30.92.192/2787.30.92.193 to 87.30.92.22287.30.92.22330
23287.30.92.224/2787.30.92.225 to 87.30.92.25487.30.92.25530
23387.30.93.0/2787.30.93.1 to 87.30.93.3087.30.93.3130
23487.30.93.32/2787.30.93.33 to 87.30.93.6287.30.93.6330
23587.30.93.64/2787.30.93.65 to 87.30.93.9487.30.93.9530
23687.30.93.96/2787.30.93.97 to 87.30.93.12687.30.93.12730
23787.30.93.128/2787.30.93.129 to 87.30.93.15887.30.93.15930
23887.30.93.160/2787.30.93.161 to 87.30.93.19087.30.93.19130
23987.30.93.192/2787.30.93.193 to 87.30.93.22287.30.93.22330
24087.30.93.224/2787.30.93.225 to 87.30.93.25487.30.93.25530
24187.30.94.0/2787.30.94.1 to 87.30.94.3087.30.94.3130
24287.30.94.32/2787.30.94.33 to 87.30.94.6287.30.94.6330
24387.30.94.64/2787.30.94.65 to 87.30.94.9487.30.94.9530
24487.30.94.96/2787.30.94.97 to 87.30.94.12687.30.94.12730
24587.30.94.128/2787.30.94.129 to 87.30.94.15887.30.94.15930
24687.30.94.160/2787.30.94.161 to 87.30.94.19087.30.94.19130
24787.30.94.192/2787.30.94.193 to 87.30.94.22287.30.94.22330
24887.30.94.224/2787.30.94.225 to 87.30.94.25487.30.94.25530
24987.30.95.0/2787.30.95.1 to 87.30.95.3087.30.95.3130
25087.30.95.32/2787.30.95.33 to 87.30.95.6287.30.95.6330
25187.30.95.64/2787.30.95.65 to 87.30.95.9487.30.95.9530
25287.30.95.96/2787.30.95.97 to 87.30.95.12687.30.95.12730
25387.30.95.128/2787.30.95.129 to 87.30.95.15887.30.95.15930
25487.30.95.160/2787.30.95.161 to 87.30.95.19087.30.95.19130
25587.30.95.192/2787.30.95.193 to 87.30.95.22287.30.95.22330
25687.30.95.224/2787.30.95.225 to 87.30.95.25487.30.95.25530

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.