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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.

Network238.128.0.0/11
Usable hosts2,097,150
Subnet mask255.224.0.0
Addresses2,097,152
Network address
238.128.0.0
Broadcast address
238.159.255.255
First usable
238.128.0.1
Last usable
238.159.255.254
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
Multicast 224.0.0.0/4
One-to-many traffic, such as IPTV and routing protocols
Old class
D (multicast)
As numbers
Hex EE800000 · Integer 4001366016 to 4003463167
Reverse DNS zones
128.238.in-addr.arpa
129.238.in-addr.arpa
130.238.in-addr.arpa
131.238.in-addr.arpa
132.238.in-addr.arpa
133.238.in-addr.arpa
134.238.in-addr.arpa
135.238.in-addr.arpa
136.238.in-addr.arpa
137.238.in-addr.arpa
138.238.in-addr.arpa
139.238.in-addr.arpa
140.238.in-addr.arpa
141.238.in-addr.arpa
142.238.in-addr.arpa
143.238.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
Address11101110.10000000.00000000.00000000238.128.0.0
Subnet mask11111111.11100000.00000000.00000000255.224.0.0
Network11101110.10000000.00000000.00000000238.128.0.0
Broadcast11101110.10011111.11111111.11111111238.159.255.255
Split into smaller subnets/22
/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)

238.128.0.0/11 makes 2,048 subnets of /22; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1238.128.0.0/22238.128.0.1 to 238.128.3.254238.128.3.2551,022
2238.128.4.0/22238.128.4.1 to 238.128.7.254238.128.7.2551,022
3238.128.8.0/22238.128.8.1 to 238.128.11.254238.128.11.2551,022
4238.128.12.0/22238.128.12.1 to 238.128.15.254238.128.15.2551,022
5238.128.16.0/22238.128.16.1 to 238.128.19.254238.128.19.2551,022
6238.128.20.0/22238.128.20.1 to 238.128.23.254238.128.23.2551,022
7238.128.24.0/22238.128.24.1 to 238.128.27.254238.128.27.2551,022
8238.128.28.0/22238.128.28.1 to 238.128.31.254238.128.31.2551,022
9238.128.32.0/22238.128.32.1 to 238.128.35.254238.128.35.2551,022
10238.128.36.0/22238.128.36.1 to 238.128.39.254238.128.39.2551,022
11238.128.40.0/22238.128.40.1 to 238.128.43.254238.128.43.2551,022
12238.128.44.0/22238.128.44.1 to 238.128.47.254238.128.47.2551,022
13238.128.48.0/22238.128.48.1 to 238.128.51.254238.128.51.2551,022
14238.128.52.0/22238.128.52.1 to 238.128.55.254238.128.55.2551,022
15238.128.56.0/22238.128.56.1 to 238.128.59.254238.128.59.2551,022
16238.128.60.0/22238.128.60.1 to 238.128.63.254238.128.63.2551,022
17238.128.64.0/22238.128.64.1 to 238.128.67.254238.128.67.2551,022
18238.128.68.0/22238.128.68.1 to 238.128.71.254238.128.71.2551,022
19238.128.72.0/22238.128.72.1 to 238.128.75.254238.128.75.2551,022
20238.128.76.0/22238.128.76.1 to 238.128.79.254238.128.79.2551,022
21238.128.80.0/22238.128.80.1 to 238.128.83.254238.128.83.2551,022
22238.128.84.0/22238.128.84.1 to 238.128.87.254238.128.87.2551,022
23238.128.88.0/22238.128.88.1 to 238.128.91.254238.128.91.2551,022
24238.128.92.0/22238.128.92.1 to 238.128.95.254238.128.95.2551,022
25238.128.96.0/22238.128.96.1 to 238.128.99.254238.128.99.2551,022
26238.128.100.0/22238.128.100.1 to 238.128.103.254238.128.103.2551,022
27238.128.104.0/22238.128.104.1 to 238.128.107.254238.128.107.2551,022
28238.128.108.0/22238.128.108.1 to 238.128.111.254238.128.111.2551,022
29238.128.112.0/22238.128.112.1 to 238.128.115.254238.128.115.2551,022
30238.128.116.0/22238.128.116.1 to 238.128.119.254238.128.119.2551,022
31238.128.120.0/22238.128.120.1 to 238.128.123.254238.128.123.2551,022
32238.128.124.0/22238.128.124.1 to 238.128.127.254238.128.127.2551,022
33238.128.128.0/22238.128.128.1 to 238.128.131.254238.128.131.2551,022
34238.128.132.0/22238.128.132.1 to 238.128.135.254238.128.135.2551,022
35238.128.136.0/22238.128.136.1 to 238.128.139.254238.128.139.2551,022
36238.128.140.0/22238.128.140.1 to 238.128.143.254238.128.143.2551,022
37238.128.144.0/22238.128.144.1 to 238.128.147.254238.128.147.2551,022
38238.128.148.0/22238.128.148.1 to 238.128.151.254238.128.151.2551,022
39238.128.152.0/22238.128.152.1 to 238.128.155.254238.128.155.2551,022
40238.128.156.0/22238.128.156.1 to 238.128.159.254238.128.159.2551,022
41238.128.160.0/22238.128.160.1 to 238.128.163.254238.128.163.2551,022
42238.128.164.0/22238.128.164.1 to 238.128.167.254238.128.167.2551,022
43238.128.168.0/22238.128.168.1 to 238.128.171.254238.128.171.2551,022
44238.128.172.0/22238.128.172.1 to 238.128.175.254238.128.175.2551,022
45238.128.176.0/22238.128.176.1 to 238.128.179.254238.128.179.2551,022
46238.128.180.0/22238.128.180.1 to 238.128.183.254238.128.183.2551,022
47238.128.184.0/22238.128.184.1 to 238.128.187.254238.128.187.2551,022
48238.128.188.0/22238.128.188.1 to 238.128.191.254238.128.191.2551,022
49238.128.192.0/22238.128.192.1 to 238.128.195.254238.128.195.2551,022
50238.128.196.0/22238.128.196.1 to 238.128.199.254238.128.199.2551,022
51238.128.200.0/22238.128.200.1 to 238.128.203.254238.128.203.2551,022
52238.128.204.0/22238.128.204.1 to 238.128.207.254238.128.207.2551,022
53238.128.208.0/22238.128.208.1 to 238.128.211.254238.128.211.2551,022
54238.128.212.0/22238.128.212.1 to 238.128.215.254238.128.215.2551,022
55238.128.216.0/22238.128.216.1 to 238.128.219.254238.128.219.2551,022
56238.128.220.0/22238.128.220.1 to 238.128.223.254238.128.223.2551,022
57238.128.224.0/22238.128.224.1 to 238.128.227.254238.128.227.2551,022
58238.128.228.0/22238.128.228.1 to 238.128.231.254238.128.231.2551,022
59238.128.232.0/22238.128.232.1 to 238.128.235.254238.128.235.2551,022
60238.128.236.0/22238.128.236.1 to 238.128.239.254238.128.239.2551,022
61238.128.240.0/22238.128.240.1 to 238.128.243.254238.128.243.2551,022
62238.128.244.0/22238.128.244.1 to 238.128.247.254238.128.247.2551,022
63238.128.248.0/22238.128.248.1 to 238.128.251.254238.128.251.2551,022
64238.128.252.0/22238.128.252.1 to 238.128.255.254238.128.255.2551,022
65238.129.0.0/22238.129.0.1 to 238.129.3.254238.129.3.2551,022
66238.129.4.0/22238.129.4.1 to 238.129.7.254238.129.7.2551,022
67238.129.8.0/22238.129.8.1 to 238.129.11.254238.129.11.2551,022
68238.129.12.0/22238.129.12.1 to 238.129.15.254238.129.15.2551,022
69238.129.16.0/22238.129.16.1 to 238.129.19.254238.129.19.2551,022
70238.129.20.0/22238.129.20.1 to 238.129.23.254238.129.23.2551,022
71238.129.24.0/22238.129.24.1 to 238.129.27.254238.129.27.2551,022
72238.129.28.0/22238.129.28.1 to 238.129.31.254238.129.31.2551,022
73238.129.32.0/22238.129.32.1 to 238.129.35.254238.129.35.2551,022
74238.129.36.0/22238.129.36.1 to 238.129.39.254238.129.39.2551,022
75238.129.40.0/22238.129.40.1 to 238.129.43.254238.129.43.2551,022
76238.129.44.0/22238.129.44.1 to 238.129.47.254238.129.47.2551,022
77238.129.48.0/22238.129.48.1 to 238.129.51.254238.129.51.2551,022
78238.129.52.0/22238.129.52.1 to 238.129.55.254238.129.55.2551,022
79238.129.56.0/22238.129.56.1 to 238.129.59.254238.129.59.2551,022
80238.129.60.0/22238.129.60.1 to 238.129.63.254238.129.63.2551,022
81238.129.64.0/22238.129.64.1 to 238.129.67.254238.129.67.2551,022
82238.129.68.0/22238.129.68.1 to 238.129.71.254238.129.71.2551,022
83238.129.72.0/22238.129.72.1 to 238.129.75.254238.129.75.2551,022
84238.129.76.0/22238.129.76.1 to 238.129.79.254238.129.79.2551,022
85238.129.80.0/22238.129.80.1 to 238.129.83.254238.129.83.2551,022
86238.129.84.0/22238.129.84.1 to 238.129.87.254238.129.87.2551,022
87238.129.88.0/22238.129.88.1 to 238.129.91.254238.129.91.2551,022
88238.129.92.0/22238.129.92.1 to 238.129.95.254238.129.95.2551,022
89238.129.96.0/22238.129.96.1 to 238.129.99.254238.129.99.2551,022
90238.129.100.0/22238.129.100.1 to 238.129.103.254238.129.103.2551,022
91238.129.104.0/22238.129.104.1 to 238.129.107.254238.129.107.2551,022
92238.129.108.0/22238.129.108.1 to 238.129.111.254238.129.111.2551,022
93238.129.112.0/22238.129.112.1 to 238.129.115.254238.129.115.2551,022
94238.129.116.0/22238.129.116.1 to 238.129.119.254238.129.119.2551,022
95238.129.120.0/22238.129.120.1 to 238.129.123.254238.129.123.2551,022
96238.129.124.0/22238.129.124.1 to 238.129.127.254238.129.127.2551,022
97238.129.128.0/22238.129.128.1 to 238.129.131.254238.129.131.2551,022
98238.129.132.0/22238.129.132.1 to 238.129.135.254238.129.135.2551,022
99238.129.136.0/22238.129.136.1 to 238.129.139.254238.129.139.2551,022
100238.129.140.0/22238.129.140.1 to 238.129.143.254238.129.143.2551,022
101238.129.144.0/22238.129.144.1 to 238.129.147.254238.129.147.2551,022
102238.129.148.0/22238.129.148.1 to 238.129.151.254238.129.151.2551,022
103238.129.152.0/22238.129.152.1 to 238.129.155.254238.129.155.2551,022
104238.129.156.0/22238.129.156.1 to 238.129.159.254238.129.159.2551,022
105238.129.160.0/22238.129.160.1 to 238.129.163.254238.129.163.2551,022
106238.129.164.0/22238.129.164.1 to 238.129.167.254238.129.167.2551,022
107238.129.168.0/22238.129.168.1 to 238.129.171.254238.129.171.2551,022
108238.129.172.0/22238.129.172.1 to 238.129.175.254238.129.175.2551,022
109238.129.176.0/22238.129.176.1 to 238.129.179.254238.129.179.2551,022
110238.129.180.0/22238.129.180.1 to 238.129.183.254238.129.183.2551,022
111238.129.184.0/22238.129.184.1 to 238.129.187.254238.129.187.2551,022
112238.129.188.0/22238.129.188.1 to 238.129.191.254238.129.191.2551,022
113238.129.192.0/22238.129.192.1 to 238.129.195.254238.129.195.2551,022
114238.129.196.0/22238.129.196.1 to 238.129.199.254238.129.199.2551,022
115238.129.200.0/22238.129.200.1 to 238.129.203.254238.129.203.2551,022
116238.129.204.0/22238.129.204.1 to 238.129.207.254238.129.207.2551,022
117238.129.208.0/22238.129.208.1 to 238.129.211.254238.129.211.2551,022
118238.129.212.0/22238.129.212.1 to 238.129.215.254238.129.215.2551,022
119238.129.216.0/22238.129.216.1 to 238.129.219.254238.129.219.2551,022
120238.129.220.0/22238.129.220.1 to 238.129.223.254238.129.223.2551,022
121238.129.224.0/22238.129.224.1 to 238.129.227.254238.129.227.2551,022
122238.129.228.0/22238.129.228.1 to 238.129.231.254238.129.231.2551,022
123238.129.232.0/22238.129.232.1 to 238.129.235.254238.129.235.2551,022
124238.129.236.0/22238.129.236.1 to 238.129.239.254238.129.239.2551,022
125238.129.240.0/22238.129.240.1 to 238.129.243.254238.129.243.2551,022
126238.129.244.0/22238.129.244.1 to 238.129.247.254238.129.247.2551,022
127238.129.248.0/22238.129.248.1 to 238.129.251.254238.129.251.2551,022
128238.129.252.0/22238.129.252.1 to 238.129.255.254238.129.255.2551,022
129238.130.0.0/22238.130.0.1 to 238.130.3.254238.130.3.2551,022
130238.130.4.0/22238.130.4.1 to 238.130.7.254238.130.7.2551,022
131238.130.8.0/22238.130.8.1 to 238.130.11.254238.130.11.2551,022
132238.130.12.0/22238.130.12.1 to 238.130.15.254238.130.15.2551,022
133238.130.16.0/22238.130.16.1 to 238.130.19.254238.130.19.2551,022
134238.130.20.0/22238.130.20.1 to 238.130.23.254238.130.23.2551,022
135238.130.24.0/22238.130.24.1 to 238.130.27.254238.130.27.2551,022
136238.130.28.0/22238.130.28.1 to 238.130.31.254238.130.31.2551,022
137238.130.32.0/22238.130.32.1 to 238.130.35.254238.130.35.2551,022
138238.130.36.0/22238.130.36.1 to 238.130.39.254238.130.39.2551,022
139238.130.40.0/22238.130.40.1 to 238.130.43.254238.130.43.2551,022
140238.130.44.0/22238.130.44.1 to 238.130.47.254238.130.47.2551,022
141238.130.48.0/22238.130.48.1 to 238.130.51.254238.130.51.2551,022
142238.130.52.0/22238.130.52.1 to 238.130.55.254238.130.55.2551,022
143238.130.56.0/22238.130.56.1 to 238.130.59.254238.130.59.2551,022
144238.130.60.0/22238.130.60.1 to 238.130.63.254238.130.63.2551,022
145238.130.64.0/22238.130.64.1 to 238.130.67.254238.130.67.2551,022
146238.130.68.0/22238.130.68.1 to 238.130.71.254238.130.71.2551,022
147238.130.72.0/22238.130.72.1 to 238.130.75.254238.130.75.2551,022
148238.130.76.0/22238.130.76.1 to 238.130.79.254238.130.79.2551,022
149238.130.80.0/22238.130.80.1 to 238.130.83.254238.130.83.2551,022
150238.130.84.0/22238.130.84.1 to 238.130.87.254238.130.87.2551,022
151238.130.88.0/22238.130.88.1 to 238.130.91.254238.130.91.2551,022
152238.130.92.0/22238.130.92.1 to 238.130.95.254238.130.95.2551,022
153238.130.96.0/22238.130.96.1 to 238.130.99.254238.130.99.2551,022
154238.130.100.0/22238.130.100.1 to 238.130.103.254238.130.103.2551,022
155238.130.104.0/22238.130.104.1 to 238.130.107.254238.130.107.2551,022
156238.130.108.0/22238.130.108.1 to 238.130.111.254238.130.111.2551,022
157238.130.112.0/22238.130.112.1 to 238.130.115.254238.130.115.2551,022
158238.130.116.0/22238.130.116.1 to 238.130.119.254238.130.119.2551,022
159238.130.120.0/22238.130.120.1 to 238.130.123.254238.130.123.2551,022
160238.130.124.0/22238.130.124.1 to 238.130.127.254238.130.127.2551,022
161238.130.128.0/22238.130.128.1 to 238.130.131.254238.130.131.2551,022
162238.130.132.0/22238.130.132.1 to 238.130.135.254238.130.135.2551,022
163238.130.136.0/22238.130.136.1 to 238.130.139.254238.130.139.2551,022
164238.130.140.0/22238.130.140.1 to 238.130.143.254238.130.143.2551,022
165238.130.144.0/22238.130.144.1 to 238.130.147.254238.130.147.2551,022
166238.130.148.0/22238.130.148.1 to 238.130.151.254238.130.151.2551,022
167238.130.152.0/22238.130.152.1 to 238.130.155.254238.130.155.2551,022
168238.130.156.0/22238.130.156.1 to 238.130.159.254238.130.159.2551,022
169238.130.160.0/22238.130.160.1 to 238.130.163.254238.130.163.2551,022
170238.130.164.0/22238.130.164.1 to 238.130.167.254238.130.167.2551,022
171238.130.168.0/22238.130.168.1 to 238.130.171.254238.130.171.2551,022
172238.130.172.0/22238.130.172.1 to 238.130.175.254238.130.175.2551,022
173238.130.176.0/22238.130.176.1 to 238.130.179.254238.130.179.2551,022
174238.130.180.0/22238.130.180.1 to 238.130.183.254238.130.183.2551,022
175238.130.184.0/22238.130.184.1 to 238.130.187.254238.130.187.2551,022
176238.130.188.0/22238.130.188.1 to 238.130.191.254238.130.191.2551,022
177238.130.192.0/22238.130.192.1 to 238.130.195.254238.130.195.2551,022
178238.130.196.0/22238.130.196.1 to 238.130.199.254238.130.199.2551,022
179238.130.200.0/22238.130.200.1 to 238.130.203.254238.130.203.2551,022
180238.130.204.0/22238.130.204.1 to 238.130.207.254238.130.207.2551,022
181238.130.208.0/22238.130.208.1 to 238.130.211.254238.130.211.2551,022
182238.130.212.0/22238.130.212.1 to 238.130.215.254238.130.215.2551,022
183238.130.216.0/22238.130.216.1 to 238.130.219.254238.130.219.2551,022
184238.130.220.0/22238.130.220.1 to 238.130.223.254238.130.223.2551,022
185238.130.224.0/22238.130.224.1 to 238.130.227.254238.130.227.2551,022
186238.130.228.0/22238.130.228.1 to 238.130.231.254238.130.231.2551,022
187238.130.232.0/22238.130.232.1 to 238.130.235.254238.130.235.2551,022
188238.130.236.0/22238.130.236.1 to 238.130.239.254238.130.239.2551,022
189238.130.240.0/22238.130.240.1 to 238.130.243.254238.130.243.2551,022
190238.130.244.0/22238.130.244.1 to 238.130.247.254238.130.247.2551,022
191238.130.248.0/22238.130.248.1 to 238.130.251.254238.130.251.2551,022
192238.130.252.0/22238.130.252.1 to 238.130.255.254238.130.255.2551,022
193238.131.0.0/22238.131.0.1 to 238.131.3.254238.131.3.2551,022
194238.131.4.0/22238.131.4.1 to 238.131.7.254238.131.7.2551,022
195238.131.8.0/22238.131.8.1 to 238.131.11.254238.131.11.2551,022
196238.131.12.0/22238.131.12.1 to 238.131.15.254238.131.15.2551,022
197238.131.16.0/22238.131.16.1 to 238.131.19.254238.131.19.2551,022
198238.131.20.0/22238.131.20.1 to 238.131.23.254238.131.23.2551,022
199238.131.24.0/22238.131.24.1 to 238.131.27.254238.131.27.2551,022
200238.131.28.0/22238.131.28.1 to 238.131.31.254238.131.31.2551,022
201238.131.32.0/22238.131.32.1 to 238.131.35.254238.131.35.2551,022
202238.131.36.0/22238.131.36.1 to 238.131.39.254238.131.39.2551,022
203238.131.40.0/22238.131.40.1 to 238.131.43.254238.131.43.2551,022
204238.131.44.0/22238.131.44.1 to 238.131.47.254238.131.47.2551,022
205238.131.48.0/22238.131.48.1 to 238.131.51.254238.131.51.2551,022
206238.131.52.0/22238.131.52.1 to 238.131.55.254238.131.55.2551,022
207238.131.56.0/22238.131.56.1 to 238.131.59.254238.131.59.2551,022
208238.131.60.0/22238.131.60.1 to 238.131.63.254238.131.63.2551,022
209238.131.64.0/22238.131.64.1 to 238.131.67.254238.131.67.2551,022
210238.131.68.0/22238.131.68.1 to 238.131.71.254238.131.71.2551,022
211238.131.72.0/22238.131.72.1 to 238.131.75.254238.131.75.2551,022
212238.131.76.0/22238.131.76.1 to 238.131.79.254238.131.79.2551,022
213238.131.80.0/22238.131.80.1 to 238.131.83.254238.131.83.2551,022
214238.131.84.0/22238.131.84.1 to 238.131.87.254238.131.87.2551,022
215238.131.88.0/22238.131.88.1 to 238.131.91.254238.131.91.2551,022
216238.131.92.0/22238.131.92.1 to 238.131.95.254238.131.95.2551,022
217238.131.96.0/22238.131.96.1 to 238.131.99.254238.131.99.2551,022
218238.131.100.0/22238.131.100.1 to 238.131.103.254238.131.103.2551,022
219238.131.104.0/22238.131.104.1 to 238.131.107.254238.131.107.2551,022
220238.131.108.0/22238.131.108.1 to 238.131.111.254238.131.111.2551,022
221238.131.112.0/22238.131.112.1 to 238.131.115.254238.131.115.2551,022
222238.131.116.0/22238.131.116.1 to 238.131.119.254238.131.119.2551,022
223238.131.120.0/22238.131.120.1 to 238.131.123.254238.131.123.2551,022
224238.131.124.0/22238.131.124.1 to 238.131.127.254238.131.127.2551,022
225238.131.128.0/22238.131.128.1 to 238.131.131.254238.131.131.2551,022
226238.131.132.0/22238.131.132.1 to 238.131.135.254238.131.135.2551,022
227238.131.136.0/22238.131.136.1 to 238.131.139.254238.131.139.2551,022
228238.131.140.0/22238.131.140.1 to 238.131.143.254238.131.143.2551,022
229238.131.144.0/22238.131.144.1 to 238.131.147.254238.131.147.2551,022
230238.131.148.0/22238.131.148.1 to 238.131.151.254238.131.151.2551,022
231238.131.152.0/22238.131.152.1 to 238.131.155.254238.131.155.2551,022
232238.131.156.0/22238.131.156.1 to 238.131.159.254238.131.159.2551,022
233238.131.160.0/22238.131.160.1 to 238.131.163.254238.131.163.2551,022
234238.131.164.0/22238.131.164.1 to 238.131.167.254238.131.167.2551,022
235238.131.168.0/22238.131.168.1 to 238.131.171.254238.131.171.2551,022
236238.131.172.0/22238.131.172.1 to 238.131.175.254238.131.175.2551,022
237238.131.176.0/22238.131.176.1 to 238.131.179.254238.131.179.2551,022
238238.131.180.0/22238.131.180.1 to 238.131.183.254238.131.183.2551,022
239238.131.184.0/22238.131.184.1 to 238.131.187.254238.131.187.2551,022
240238.131.188.0/22238.131.188.1 to 238.131.191.254238.131.191.2551,022
241238.131.192.0/22238.131.192.1 to 238.131.195.254238.131.195.2551,022
242238.131.196.0/22238.131.196.1 to 238.131.199.254238.131.199.2551,022
243238.131.200.0/22238.131.200.1 to 238.131.203.254238.131.203.2551,022
244238.131.204.0/22238.131.204.1 to 238.131.207.254238.131.207.2551,022
245238.131.208.0/22238.131.208.1 to 238.131.211.254238.131.211.2551,022
246238.131.212.0/22238.131.212.1 to 238.131.215.254238.131.215.2551,022
247238.131.216.0/22238.131.216.1 to 238.131.219.254238.131.219.2551,022
248238.131.220.0/22238.131.220.1 to 238.131.223.254238.131.223.2551,022
249238.131.224.0/22238.131.224.1 to 238.131.227.254238.131.227.2551,022
250238.131.228.0/22238.131.228.1 to 238.131.231.254238.131.231.2551,022
251238.131.232.0/22238.131.232.1 to 238.131.235.254238.131.235.2551,022
252238.131.236.0/22238.131.236.1 to 238.131.239.254238.131.239.2551,022
253238.131.240.0/22238.131.240.1 to 238.131.243.254238.131.243.2551,022
254238.131.244.0/22238.131.244.1 to 238.131.247.254238.131.247.2551,022
255238.131.248.0/22238.131.248.1 to 238.131.251.254238.131.251.2551,022
256238.131.252.0/22238.131.252.1 to 238.131.255.254238.131.255.2551,022

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.