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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.

Network27.128.0.0/11
Usable hosts2,097,150
Subnet mask255.224.0.0
Addresses2,097,152
Network address
27.128.0.0
Broadcast address
27.159.255.255
First usable
27.128.0.1
Last usable
27.159.255.254
Usable hosts
2,097,150 (2,097,152 less the network and broadcast addresses)
Subnet mask
255.224.0.0
Wildcard mask
0.31.255.255 (Cisco ACLs, OSPF)
Prefix length
/11
Type
Public public
Old class
A (default /8)
As numbers
Hex 1B800000 · Integer 461373440 to 463470591
Reverse DNS zones
128.27.in-addr.arpa
129.27.in-addr.arpa
130.27.in-addr.arpa
131.27.in-addr.arpa
132.27.in-addr.arpa
133.27.in-addr.arpa
134.27.in-addr.arpa
135.27.in-addr.arpa
136.27.in-addr.arpa
137.27.in-addr.arpa
138.27.in-addr.arpa
139.27.in-addr.arpa
140.27.in-addr.arpa
141.27.in-addr.arpa
142.27.in-addr.arpa
143.27.in-addr.arpa
and 16 more
/11 is not on a 8-bit boundary, so it takes 32 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00011011.10000000.00000000.0000000027.128.0.0
Subnet mask11111111.11100000.00000000.00000000255.224.0.0
Network00011011.10000000.00000000.0000000027.128.0.0
Broadcast00011011.10011111.11111111.1111111127.159.255.255
Split into smaller subnets/21
/12 (2)/13 (4)/14 (8)/15 (16)/16 (32)/17 (64)/18 (128)/19 (256)/20 (512)/21 (1,024)/22 (2,048)/23 (4,096)

27.128.0.0/11 makes 1,024 subnets of /21; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
127.128.0.0/2127.128.0.1 to 27.128.7.25427.128.7.2552,046
227.128.8.0/2127.128.8.1 to 27.128.15.25427.128.15.2552,046
327.128.16.0/2127.128.16.1 to 27.128.23.25427.128.23.2552,046
427.128.24.0/2127.128.24.1 to 27.128.31.25427.128.31.2552,046
527.128.32.0/2127.128.32.1 to 27.128.39.25427.128.39.2552,046
627.128.40.0/2127.128.40.1 to 27.128.47.25427.128.47.2552,046
727.128.48.0/2127.128.48.1 to 27.128.55.25427.128.55.2552,046
827.128.56.0/2127.128.56.1 to 27.128.63.25427.128.63.2552,046
927.128.64.0/2127.128.64.1 to 27.128.71.25427.128.71.2552,046
1027.128.72.0/2127.128.72.1 to 27.128.79.25427.128.79.2552,046
1127.128.80.0/2127.128.80.1 to 27.128.87.25427.128.87.2552,046
1227.128.88.0/2127.128.88.1 to 27.128.95.25427.128.95.2552,046
1327.128.96.0/2127.128.96.1 to 27.128.103.25427.128.103.2552,046
1427.128.104.0/2127.128.104.1 to 27.128.111.25427.128.111.2552,046
1527.128.112.0/2127.128.112.1 to 27.128.119.25427.128.119.2552,046
1627.128.120.0/2127.128.120.1 to 27.128.127.25427.128.127.2552,046
1727.128.128.0/2127.128.128.1 to 27.128.135.25427.128.135.2552,046
1827.128.136.0/2127.128.136.1 to 27.128.143.25427.128.143.2552,046
1927.128.144.0/2127.128.144.1 to 27.128.151.25427.128.151.2552,046
2027.128.152.0/2127.128.152.1 to 27.128.159.25427.128.159.2552,046
2127.128.160.0/2127.128.160.1 to 27.128.167.25427.128.167.2552,046
2227.128.168.0/2127.128.168.1 to 27.128.175.25427.128.175.2552,046
2327.128.176.0/2127.128.176.1 to 27.128.183.25427.128.183.2552,046
2427.128.184.0/2127.128.184.1 to 27.128.191.25427.128.191.2552,046
2527.128.192.0/2127.128.192.1 to 27.128.199.25427.128.199.2552,046
2627.128.200.0/2127.128.200.1 to 27.128.207.25427.128.207.2552,046
2727.128.208.0/2127.128.208.1 to 27.128.215.25427.128.215.2552,046
2827.128.216.0/2127.128.216.1 to 27.128.223.25427.128.223.2552,046
2927.128.224.0/2127.128.224.1 to 27.128.231.25427.128.231.2552,046
3027.128.232.0/2127.128.232.1 to 27.128.239.25427.128.239.2552,046
3127.128.240.0/2127.128.240.1 to 27.128.247.25427.128.247.2552,046
3227.128.248.0/2127.128.248.1 to 27.128.255.25427.128.255.2552,046
3327.129.0.0/2127.129.0.1 to 27.129.7.25427.129.7.2552,046
3427.129.8.0/2127.129.8.1 to 27.129.15.25427.129.15.2552,046
3527.129.16.0/2127.129.16.1 to 27.129.23.25427.129.23.2552,046
3627.129.24.0/2127.129.24.1 to 27.129.31.25427.129.31.2552,046
3727.129.32.0/2127.129.32.1 to 27.129.39.25427.129.39.2552,046
3827.129.40.0/2127.129.40.1 to 27.129.47.25427.129.47.2552,046
3927.129.48.0/2127.129.48.1 to 27.129.55.25427.129.55.2552,046
4027.129.56.0/2127.129.56.1 to 27.129.63.25427.129.63.2552,046
4127.129.64.0/2127.129.64.1 to 27.129.71.25427.129.71.2552,046
4227.129.72.0/2127.129.72.1 to 27.129.79.25427.129.79.2552,046
4327.129.80.0/2127.129.80.1 to 27.129.87.25427.129.87.2552,046
4427.129.88.0/2127.129.88.1 to 27.129.95.25427.129.95.2552,046
4527.129.96.0/2127.129.96.1 to 27.129.103.25427.129.103.2552,046
4627.129.104.0/2127.129.104.1 to 27.129.111.25427.129.111.2552,046
4727.129.112.0/2127.129.112.1 to 27.129.119.25427.129.119.2552,046
4827.129.120.0/2127.129.120.1 to 27.129.127.25427.129.127.2552,046
4927.129.128.0/2127.129.128.1 to 27.129.135.25427.129.135.2552,046
5027.129.136.0/2127.129.136.1 to 27.129.143.25427.129.143.2552,046
5127.129.144.0/2127.129.144.1 to 27.129.151.25427.129.151.2552,046
5227.129.152.0/2127.129.152.1 to 27.129.159.25427.129.159.2552,046
5327.129.160.0/2127.129.160.1 to 27.129.167.25427.129.167.2552,046
5427.129.168.0/2127.129.168.1 to 27.129.175.25427.129.175.2552,046
5527.129.176.0/2127.129.176.1 to 27.129.183.25427.129.183.2552,046
5627.129.184.0/2127.129.184.1 to 27.129.191.25427.129.191.2552,046
5727.129.192.0/2127.129.192.1 to 27.129.199.25427.129.199.2552,046
5827.129.200.0/2127.129.200.1 to 27.129.207.25427.129.207.2552,046
5927.129.208.0/2127.129.208.1 to 27.129.215.25427.129.215.2552,046
6027.129.216.0/2127.129.216.1 to 27.129.223.25427.129.223.2552,046
6127.129.224.0/2127.129.224.1 to 27.129.231.25427.129.231.2552,046
6227.129.232.0/2127.129.232.1 to 27.129.239.25427.129.239.2552,046
6327.129.240.0/2127.129.240.1 to 27.129.247.25427.129.247.2552,046
6427.129.248.0/2127.129.248.1 to 27.129.255.25427.129.255.2552,046
6527.130.0.0/2127.130.0.1 to 27.130.7.25427.130.7.2552,046
6627.130.8.0/2127.130.8.1 to 27.130.15.25427.130.15.2552,046
6727.130.16.0/2127.130.16.1 to 27.130.23.25427.130.23.2552,046
6827.130.24.0/2127.130.24.1 to 27.130.31.25427.130.31.2552,046
6927.130.32.0/2127.130.32.1 to 27.130.39.25427.130.39.2552,046
7027.130.40.0/2127.130.40.1 to 27.130.47.25427.130.47.2552,046
7127.130.48.0/2127.130.48.1 to 27.130.55.25427.130.55.2552,046
7227.130.56.0/2127.130.56.1 to 27.130.63.25427.130.63.2552,046
7327.130.64.0/2127.130.64.1 to 27.130.71.25427.130.71.2552,046
7427.130.72.0/2127.130.72.1 to 27.130.79.25427.130.79.2552,046
7527.130.80.0/2127.130.80.1 to 27.130.87.25427.130.87.2552,046
7627.130.88.0/2127.130.88.1 to 27.130.95.25427.130.95.2552,046
7727.130.96.0/2127.130.96.1 to 27.130.103.25427.130.103.2552,046
7827.130.104.0/2127.130.104.1 to 27.130.111.25427.130.111.2552,046
7927.130.112.0/2127.130.112.1 to 27.130.119.25427.130.119.2552,046
8027.130.120.0/2127.130.120.1 to 27.130.127.25427.130.127.2552,046
8127.130.128.0/2127.130.128.1 to 27.130.135.25427.130.135.2552,046
8227.130.136.0/2127.130.136.1 to 27.130.143.25427.130.143.2552,046
8327.130.144.0/2127.130.144.1 to 27.130.151.25427.130.151.2552,046
8427.130.152.0/2127.130.152.1 to 27.130.159.25427.130.159.2552,046
8527.130.160.0/2127.130.160.1 to 27.130.167.25427.130.167.2552,046
8627.130.168.0/2127.130.168.1 to 27.130.175.25427.130.175.2552,046
8727.130.176.0/2127.130.176.1 to 27.130.183.25427.130.183.2552,046
8827.130.184.0/2127.130.184.1 to 27.130.191.25427.130.191.2552,046
8927.130.192.0/2127.130.192.1 to 27.130.199.25427.130.199.2552,046
9027.130.200.0/2127.130.200.1 to 27.130.207.25427.130.207.2552,046
9127.130.208.0/2127.130.208.1 to 27.130.215.25427.130.215.2552,046
9227.130.216.0/2127.130.216.1 to 27.130.223.25427.130.223.2552,046
9327.130.224.0/2127.130.224.1 to 27.130.231.25427.130.231.2552,046
9427.130.232.0/2127.130.232.1 to 27.130.239.25427.130.239.2552,046
9527.130.240.0/2127.130.240.1 to 27.130.247.25427.130.247.2552,046
9627.130.248.0/2127.130.248.1 to 27.130.255.25427.130.255.2552,046
9727.131.0.0/2127.131.0.1 to 27.131.7.25427.131.7.2552,046
9827.131.8.0/2127.131.8.1 to 27.131.15.25427.131.15.2552,046
9927.131.16.0/2127.131.16.1 to 27.131.23.25427.131.23.2552,046
10027.131.24.0/2127.131.24.1 to 27.131.31.25427.131.31.2552,046
10127.131.32.0/2127.131.32.1 to 27.131.39.25427.131.39.2552,046
10227.131.40.0/2127.131.40.1 to 27.131.47.25427.131.47.2552,046
10327.131.48.0/2127.131.48.1 to 27.131.55.25427.131.55.2552,046
10427.131.56.0/2127.131.56.1 to 27.131.63.25427.131.63.2552,046
10527.131.64.0/2127.131.64.1 to 27.131.71.25427.131.71.2552,046
10627.131.72.0/2127.131.72.1 to 27.131.79.25427.131.79.2552,046
10727.131.80.0/2127.131.80.1 to 27.131.87.25427.131.87.2552,046
10827.131.88.0/2127.131.88.1 to 27.131.95.25427.131.95.2552,046
10927.131.96.0/2127.131.96.1 to 27.131.103.25427.131.103.2552,046
11027.131.104.0/2127.131.104.1 to 27.131.111.25427.131.111.2552,046
11127.131.112.0/2127.131.112.1 to 27.131.119.25427.131.119.2552,046
11227.131.120.0/2127.131.120.1 to 27.131.127.25427.131.127.2552,046
11327.131.128.0/2127.131.128.1 to 27.131.135.25427.131.135.2552,046
11427.131.136.0/2127.131.136.1 to 27.131.143.25427.131.143.2552,046
11527.131.144.0/2127.131.144.1 to 27.131.151.25427.131.151.2552,046
11627.131.152.0/2127.131.152.1 to 27.131.159.25427.131.159.2552,046
11727.131.160.0/2127.131.160.1 to 27.131.167.25427.131.167.2552,046
11827.131.168.0/2127.131.168.1 to 27.131.175.25427.131.175.2552,046
11927.131.176.0/2127.131.176.1 to 27.131.183.25427.131.183.2552,046
12027.131.184.0/2127.131.184.1 to 27.131.191.25427.131.191.2552,046
12127.131.192.0/2127.131.192.1 to 27.131.199.25427.131.199.2552,046
12227.131.200.0/2127.131.200.1 to 27.131.207.25427.131.207.2552,046
12327.131.208.0/2127.131.208.1 to 27.131.215.25427.131.215.2552,046
12427.131.216.0/2127.131.216.1 to 27.131.223.25427.131.223.2552,046
12527.131.224.0/2127.131.224.1 to 27.131.231.25427.131.231.2552,046
12627.131.232.0/2127.131.232.1 to 27.131.239.25427.131.239.2552,046
12727.131.240.0/2127.131.240.1 to 27.131.247.25427.131.247.2552,046
12827.131.248.0/2127.131.248.1 to 27.131.255.25427.131.255.2552,046
12927.132.0.0/2127.132.0.1 to 27.132.7.25427.132.7.2552,046
13027.132.8.0/2127.132.8.1 to 27.132.15.25427.132.15.2552,046
13127.132.16.0/2127.132.16.1 to 27.132.23.25427.132.23.2552,046
13227.132.24.0/2127.132.24.1 to 27.132.31.25427.132.31.2552,046
13327.132.32.0/2127.132.32.1 to 27.132.39.25427.132.39.2552,046
13427.132.40.0/2127.132.40.1 to 27.132.47.25427.132.47.2552,046
13527.132.48.0/2127.132.48.1 to 27.132.55.25427.132.55.2552,046
13627.132.56.0/2127.132.56.1 to 27.132.63.25427.132.63.2552,046
13727.132.64.0/2127.132.64.1 to 27.132.71.25427.132.71.2552,046
13827.132.72.0/2127.132.72.1 to 27.132.79.25427.132.79.2552,046
13927.132.80.0/2127.132.80.1 to 27.132.87.25427.132.87.2552,046
14027.132.88.0/2127.132.88.1 to 27.132.95.25427.132.95.2552,046
14127.132.96.0/2127.132.96.1 to 27.132.103.25427.132.103.2552,046
14227.132.104.0/2127.132.104.1 to 27.132.111.25427.132.111.2552,046
14327.132.112.0/2127.132.112.1 to 27.132.119.25427.132.119.2552,046
14427.132.120.0/2127.132.120.1 to 27.132.127.25427.132.127.2552,046
14527.132.128.0/2127.132.128.1 to 27.132.135.25427.132.135.2552,046
14627.132.136.0/2127.132.136.1 to 27.132.143.25427.132.143.2552,046
14727.132.144.0/2127.132.144.1 to 27.132.151.25427.132.151.2552,046
14827.132.152.0/2127.132.152.1 to 27.132.159.25427.132.159.2552,046
14927.132.160.0/2127.132.160.1 to 27.132.167.25427.132.167.2552,046
15027.132.168.0/2127.132.168.1 to 27.132.175.25427.132.175.2552,046
15127.132.176.0/2127.132.176.1 to 27.132.183.25427.132.183.2552,046
15227.132.184.0/2127.132.184.1 to 27.132.191.25427.132.191.2552,046
15327.132.192.0/2127.132.192.1 to 27.132.199.25427.132.199.2552,046
15427.132.200.0/2127.132.200.1 to 27.132.207.25427.132.207.2552,046
15527.132.208.0/2127.132.208.1 to 27.132.215.25427.132.215.2552,046
15627.132.216.0/2127.132.216.1 to 27.132.223.25427.132.223.2552,046
15727.132.224.0/2127.132.224.1 to 27.132.231.25427.132.231.2552,046
15827.132.232.0/2127.132.232.1 to 27.132.239.25427.132.239.2552,046
15927.132.240.0/2127.132.240.1 to 27.132.247.25427.132.247.2552,046
16027.132.248.0/2127.132.248.1 to 27.132.255.25427.132.255.2552,046
16127.133.0.0/2127.133.0.1 to 27.133.7.25427.133.7.2552,046
16227.133.8.0/2127.133.8.1 to 27.133.15.25427.133.15.2552,046
16327.133.16.0/2127.133.16.1 to 27.133.23.25427.133.23.2552,046
16427.133.24.0/2127.133.24.1 to 27.133.31.25427.133.31.2552,046
16527.133.32.0/2127.133.32.1 to 27.133.39.25427.133.39.2552,046
16627.133.40.0/2127.133.40.1 to 27.133.47.25427.133.47.2552,046
16727.133.48.0/2127.133.48.1 to 27.133.55.25427.133.55.2552,046
16827.133.56.0/2127.133.56.1 to 27.133.63.25427.133.63.2552,046
16927.133.64.0/2127.133.64.1 to 27.133.71.25427.133.71.2552,046
17027.133.72.0/2127.133.72.1 to 27.133.79.25427.133.79.2552,046
17127.133.80.0/2127.133.80.1 to 27.133.87.25427.133.87.2552,046
17227.133.88.0/2127.133.88.1 to 27.133.95.25427.133.95.2552,046
17327.133.96.0/2127.133.96.1 to 27.133.103.25427.133.103.2552,046
17427.133.104.0/2127.133.104.1 to 27.133.111.25427.133.111.2552,046
17527.133.112.0/2127.133.112.1 to 27.133.119.25427.133.119.2552,046
17627.133.120.0/2127.133.120.1 to 27.133.127.25427.133.127.2552,046
17727.133.128.0/2127.133.128.1 to 27.133.135.25427.133.135.2552,046
17827.133.136.0/2127.133.136.1 to 27.133.143.25427.133.143.2552,046
17927.133.144.0/2127.133.144.1 to 27.133.151.25427.133.151.2552,046
18027.133.152.0/2127.133.152.1 to 27.133.159.25427.133.159.2552,046
18127.133.160.0/2127.133.160.1 to 27.133.167.25427.133.167.2552,046
18227.133.168.0/2127.133.168.1 to 27.133.175.25427.133.175.2552,046
18327.133.176.0/2127.133.176.1 to 27.133.183.25427.133.183.2552,046
18427.133.184.0/2127.133.184.1 to 27.133.191.25427.133.191.2552,046
18527.133.192.0/2127.133.192.1 to 27.133.199.25427.133.199.2552,046
18627.133.200.0/2127.133.200.1 to 27.133.207.25427.133.207.2552,046
18727.133.208.0/2127.133.208.1 to 27.133.215.25427.133.215.2552,046
18827.133.216.0/2127.133.216.1 to 27.133.223.25427.133.223.2552,046
18927.133.224.0/2127.133.224.1 to 27.133.231.25427.133.231.2552,046
19027.133.232.0/2127.133.232.1 to 27.133.239.25427.133.239.2552,046
19127.133.240.0/2127.133.240.1 to 27.133.247.25427.133.247.2552,046
19227.133.248.0/2127.133.248.1 to 27.133.255.25427.133.255.2552,046
19327.134.0.0/2127.134.0.1 to 27.134.7.25427.134.7.2552,046
19427.134.8.0/2127.134.8.1 to 27.134.15.25427.134.15.2552,046
19527.134.16.0/2127.134.16.1 to 27.134.23.25427.134.23.2552,046
19627.134.24.0/2127.134.24.1 to 27.134.31.25427.134.31.2552,046
19727.134.32.0/2127.134.32.1 to 27.134.39.25427.134.39.2552,046
19827.134.40.0/2127.134.40.1 to 27.134.47.25427.134.47.2552,046
19927.134.48.0/2127.134.48.1 to 27.134.55.25427.134.55.2552,046
20027.134.56.0/2127.134.56.1 to 27.134.63.25427.134.63.2552,046
20127.134.64.0/2127.134.64.1 to 27.134.71.25427.134.71.2552,046
20227.134.72.0/2127.134.72.1 to 27.134.79.25427.134.79.2552,046
20327.134.80.0/2127.134.80.1 to 27.134.87.25427.134.87.2552,046
20427.134.88.0/2127.134.88.1 to 27.134.95.25427.134.95.2552,046
20527.134.96.0/2127.134.96.1 to 27.134.103.25427.134.103.2552,046
20627.134.104.0/2127.134.104.1 to 27.134.111.25427.134.111.2552,046
20727.134.112.0/2127.134.112.1 to 27.134.119.25427.134.119.2552,046
20827.134.120.0/2127.134.120.1 to 27.134.127.25427.134.127.2552,046
20927.134.128.0/2127.134.128.1 to 27.134.135.25427.134.135.2552,046
21027.134.136.0/2127.134.136.1 to 27.134.143.25427.134.143.2552,046
21127.134.144.0/2127.134.144.1 to 27.134.151.25427.134.151.2552,046
21227.134.152.0/2127.134.152.1 to 27.134.159.25427.134.159.2552,046
21327.134.160.0/2127.134.160.1 to 27.134.167.25427.134.167.2552,046
21427.134.168.0/2127.134.168.1 to 27.134.175.25427.134.175.2552,046
21527.134.176.0/2127.134.176.1 to 27.134.183.25427.134.183.2552,046
21627.134.184.0/2127.134.184.1 to 27.134.191.25427.134.191.2552,046
21727.134.192.0/2127.134.192.1 to 27.134.199.25427.134.199.2552,046
21827.134.200.0/2127.134.200.1 to 27.134.207.25427.134.207.2552,046
21927.134.208.0/2127.134.208.1 to 27.134.215.25427.134.215.2552,046
22027.134.216.0/2127.134.216.1 to 27.134.223.25427.134.223.2552,046
22127.134.224.0/2127.134.224.1 to 27.134.231.25427.134.231.2552,046
22227.134.232.0/2127.134.232.1 to 27.134.239.25427.134.239.2552,046
22327.134.240.0/2127.134.240.1 to 27.134.247.25427.134.247.2552,046
22427.134.248.0/2127.134.248.1 to 27.134.255.25427.134.255.2552,046
22527.135.0.0/2127.135.0.1 to 27.135.7.25427.135.7.2552,046
22627.135.8.0/2127.135.8.1 to 27.135.15.25427.135.15.2552,046
22727.135.16.0/2127.135.16.1 to 27.135.23.25427.135.23.2552,046
22827.135.24.0/2127.135.24.1 to 27.135.31.25427.135.31.2552,046
22927.135.32.0/2127.135.32.1 to 27.135.39.25427.135.39.2552,046
23027.135.40.0/2127.135.40.1 to 27.135.47.25427.135.47.2552,046
23127.135.48.0/2127.135.48.1 to 27.135.55.25427.135.55.2552,046
23227.135.56.0/2127.135.56.1 to 27.135.63.25427.135.63.2552,046
23327.135.64.0/2127.135.64.1 to 27.135.71.25427.135.71.2552,046
23427.135.72.0/2127.135.72.1 to 27.135.79.25427.135.79.2552,046
23527.135.80.0/2127.135.80.1 to 27.135.87.25427.135.87.2552,046
23627.135.88.0/2127.135.88.1 to 27.135.95.25427.135.95.2552,046
23727.135.96.0/2127.135.96.1 to 27.135.103.25427.135.103.2552,046
23827.135.104.0/2127.135.104.1 to 27.135.111.25427.135.111.2552,046
23927.135.112.0/2127.135.112.1 to 27.135.119.25427.135.119.2552,046
24027.135.120.0/2127.135.120.1 to 27.135.127.25427.135.127.2552,046
24127.135.128.0/2127.135.128.1 to 27.135.135.25427.135.135.2552,046
24227.135.136.0/2127.135.136.1 to 27.135.143.25427.135.143.2552,046
24327.135.144.0/2127.135.144.1 to 27.135.151.25427.135.151.2552,046
24427.135.152.0/2127.135.152.1 to 27.135.159.25427.135.159.2552,046
24527.135.160.0/2127.135.160.1 to 27.135.167.25427.135.167.2552,046
24627.135.168.0/2127.135.168.1 to 27.135.175.25427.135.175.2552,046
24727.135.176.0/2127.135.176.1 to 27.135.183.25427.135.183.2552,046
24827.135.184.0/2127.135.184.1 to 27.135.191.25427.135.191.2552,046
24927.135.192.0/2127.135.192.1 to 27.135.199.25427.135.199.2552,046
25027.135.200.0/2127.135.200.1 to 27.135.207.25427.135.207.2552,046
25127.135.208.0/2127.135.208.1 to 27.135.215.25427.135.215.2552,046
25227.135.216.0/2127.135.216.1 to 27.135.223.25427.135.223.2552,046
25327.135.224.0/2127.135.224.1 to 27.135.231.25427.135.231.2552,046
25427.135.232.0/2127.135.232.1 to 27.135.239.25427.135.239.2552,046
25527.135.240.0/2127.135.240.1 to 27.135.247.25427.135.247.2552,046
25627.135.248.0/2127.135.248.1 to 27.135.255.25427.135.255.2552,046

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.