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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.

Network212.0.0.0/13
Usable hosts524,286
Subnet mask255.248.0.0
Addresses524,288
Network address
212.0.0.0
Broadcast address
212.7.255.255
First usable
212.0.0.1
Last usable
212.7.255.254
Usable hosts
524,286 (524,288 less the network and broadcast addresses)
Subnet mask
255.248.0.0
Wildcard mask
0.7.255.255 (Cisco ACLs, OSPF)
Prefix length
/13
Type
Public public
Old class
C (default /24)
As numbers
Hex D4000000 · Integer 3556769792 to 3557294079
Reverse DNS zones
0.212.in-addr.arpa
1.212.in-addr.arpa
2.212.in-addr.arpa
3.212.in-addr.arpa
4.212.in-addr.arpa
5.212.in-addr.arpa
6.212.in-addr.arpa
7.212.in-addr.arpa
/13 is not on a 8-bit boundary, so it takes 8 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11010100.00000000.00000000.00000000212.0.0.0
Subnet mask11111111.11111000.00000000.00000000255.248.0.0
Network11010100.00000000.00000000.00000000212.0.0.0
Broadcast11010100.00000111.11111111.11111111212.7.255.255
Split into smaller subnets/23
/14 (2)/15 (4)/16 (8)/17 (16)/18 (32)/19 (64)/20 (128)/21 (256)/22 (512)/23 (1,024)/24 (2,048)/25 (4,096)

212.0.0.0/13 makes 1,024 subnets of /23; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1212.0.0.0/23212.0.0.1 to 212.0.1.254212.0.1.255510
2212.0.2.0/23212.0.2.1 to 212.0.3.254212.0.3.255510
3212.0.4.0/23212.0.4.1 to 212.0.5.254212.0.5.255510
4212.0.6.0/23212.0.6.1 to 212.0.7.254212.0.7.255510
5212.0.8.0/23212.0.8.1 to 212.0.9.254212.0.9.255510
6212.0.10.0/23212.0.10.1 to 212.0.11.254212.0.11.255510
7212.0.12.0/23212.0.12.1 to 212.0.13.254212.0.13.255510
8212.0.14.0/23212.0.14.1 to 212.0.15.254212.0.15.255510
9212.0.16.0/23212.0.16.1 to 212.0.17.254212.0.17.255510
10212.0.18.0/23212.0.18.1 to 212.0.19.254212.0.19.255510
11212.0.20.0/23212.0.20.1 to 212.0.21.254212.0.21.255510
12212.0.22.0/23212.0.22.1 to 212.0.23.254212.0.23.255510
13212.0.24.0/23212.0.24.1 to 212.0.25.254212.0.25.255510
14212.0.26.0/23212.0.26.1 to 212.0.27.254212.0.27.255510
15212.0.28.0/23212.0.28.1 to 212.0.29.254212.0.29.255510
16212.0.30.0/23212.0.30.1 to 212.0.31.254212.0.31.255510
17212.0.32.0/23212.0.32.1 to 212.0.33.254212.0.33.255510
18212.0.34.0/23212.0.34.1 to 212.0.35.254212.0.35.255510
19212.0.36.0/23212.0.36.1 to 212.0.37.254212.0.37.255510
20212.0.38.0/23212.0.38.1 to 212.0.39.254212.0.39.255510
21212.0.40.0/23212.0.40.1 to 212.0.41.254212.0.41.255510
22212.0.42.0/23212.0.42.1 to 212.0.43.254212.0.43.255510
23212.0.44.0/23212.0.44.1 to 212.0.45.254212.0.45.255510
24212.0.46.0/23212.0.46.1 to 212.0.47.254212.0.47.255510
25212.0.48.0/23212.0.48.1 to 212.0.49.254212.0.49.255510
26212.0.50.0/23212.0.50.1 to 212.0.51.254212.0.51.255510
27212.0.52.0/23212.0.52.1 to 212.0.53.254212.0.53.255510
28212.0.54.0/23212.0.54.1 to 212.0.55.254212.0.55.255510
29212.0.56.0/23212.0.56.1 to 212.0.57.254212.0.57.255510
30212.0.58.0/23212.0.58.1 to 212.0.59.254212.0.59.255510
31212.0.60.0/23212.0.60.1 to 212.0.61.254212.0.61.255510
32212.0.62.0/23212.0.62.1 to 212.0.63.254212.0.63.255510
33212.0.64.0/23212.0.64.1 to 212.0.65.254212.0.65.255510
34212.0.66.0/23212.0.66.1 to 212.0.67.254212.0.67.255510
35212.0.68.0/23212.0.68.1 to 212.0.69.254212.0.69.255510
36212.0.70.0/23212.0.70.1 to 212.0.71.254212.0.71.255510
37212.0.72.0/23212.0.72.1 to 212.0.73.254212.0.73.255510
38212.0.74.0/23212.0.74.1 to 212.0.75.254212.0.75.255510
39212.0.76.0/23212.0.76.1 to 212.0.77.254212.0.77.255510
40212.0.78.0/23212.0.78.1 to 212.0.79.254212.0.79.255510
41212.0.80.0/23212.0.80.1 to 212.0.81.254212.0.81.255510
42212.0.82.0/23212.0.82.1 to 212.0.83.254212.0.83.255510
43212.0.84.0/23212.0.84.1 to 212.0.85.254212.0.85.255510
44212.0.86.0/23212.0.86.1 to 212.0.87.254212.0.87.255510
45212.0.88.0/23212.0.88.1 to 212.0.89.254212.0.89.255510
46212.0.90.0/23212.0.90.1 to 212.0.91.254212.0.91.255510
47212.0.92.0/23212.0.92.1 to 212.0.93.254212.0.93.255510
48212.0.94.0/23212.0.94.1 to 212.0.95.254212.0.95.255510
49212.0.96.0/23212.0.96.1 to 212.0.97.254212.0.97.255510
50212.0.98.0/23212.0.98.1 to 212.0.99.254212.0.99.255510
51212.0.100.0/23212.0.100.1 to 212.0.101.254212.0.101.255510
52212.0.102.0/23212.0.102.1 to 212.0.103.254212.0.103.255510
53212.0.104.0/23212.0.104.1 to 212.0.105.254212.0.105.255510
54212.0.106.0/23212.0.106.1 to 212.0.107.254212.0.107.255510
55212.0.108.0/23212.0.108.1 to 212.0.109.254212.0.109.255510
56212.0.110.0/23212.0.110.1 to 212.0.111.254212.0.111.255510
57212.0.112.0/23212.0.112.1 to 212.0.113.254212.0.113.255510
58212.0.114.0/23212.0.114.1 to 212.0.115.254212.0.115.255510
59212.0.116.0/23212.0.116.1 to 212.0.117.254212.0.117.255510
60212.0.118.0/23212.0.118.1 to 212.0.119.254212.0.119.255510
61212.0.120.0/23212.0.120.1 to 212.0.121.254212.0.121.255510
62212.0.122.0/23212.0.122.1 to 212.0.123.254212.0.123.255510
63212.0.124.0/23212.0.124.1 to 212.0.125.254212.0.125.255510
64212.0.126.0/23212.0.126.1 to 212.0.127.254212.0.127.255510
65212.0.128.0/23212.0.128.1 to 212.0.129.254212.0.129.255510
66212.0.130.0/23212.0.130.1 to 212.0.131.254212.0.131.255510
67212.0.132.0/23212.0.132.1 to 212.0.133.254212.0.133.255510
68212.0.134.0/23212.0.134.1 to 212.0.135.254212.0.135.255510
69212.0.136.0/23212.0.136.1 to 212.0.137.254212.0.137.255510
70212.0.138.0/23212.0.138.1 to 212.0.139.254212.0.139.255510
71212.0.140.0/23212.0.140.1 to 212.0.141.254212.0.141.255510
72212.0.142.0/23212.0.142.1 to 212.0.143.254212.0.143.255510
73212.0.144.0/23212.0.144.1 to 212.0.145.254212.0.145.255510
74212.0.146.0/23212.0.146.1 to 212.0.147.254212.0.147.255510
75212.0.148.0/23212.0.148.1 to 212.0.149.254212.0.149.255510
76212.0.150.0/23212.0.150.1 to 212.0.151.254212.0.151.255510
77212.0.152.0/23212.0.152.1 to 212.0.153.254212.0.153.255510
78212.0.154.0/23212.0.154.1 to 212.0.155.254212.0.155.255510
79212.0.156.0/23212.0.156.1 to 212.0.157.254212.0.157.255510
80212.0.158.0/23212.0.158.1 to 212.0.159.254212.0.159.255510
81212.0.160.0/23212.0.160.1 to 212.0.161.254212.0.161.255510
82212.0.162.0/23212.0.162.1 to 212.0.163.254212.0.163.255510
83212.0.164.0/23212.0.164.1 to 212.0.165.254212.0.165.255510
84212.0.166.0/23212.0.166.1 to 212.0.167.254212.0.167.255510
85212.0.168.0/23212.0.168.1 to 212.0.169.254212.0.169.255510
86212.0.170.0/23212.0.170.1 to 212.0.171.254212.0.171.255510
87212.0.172.0/23212.0.172.1 to 212.0.173.254212.0.173.255510
88212.0.174.0/23212.0.174.1 to 212.0.175.254212.0.175.255510
89212.0.176.0/23212.0.176.1 to 212.0.177.254212.0.177.255510
90212.0.178.0/23212.0.178.1 to 212.0.179.254212.0.179.255510
91212.0.180.0/23212.0.180.1 to 212.0.181.254212.0.181.255510
92212.0.182.0/23212.0.182.1 to 212.0.183.254212.0.183.255510
93212.0.184.0/23212.0.184.1 to 212.0.185.254212.0.185.255510
94212.0.186.0/23212.0.186.1 to 212.0.187.254212.0.187.255510
95212.0.188.0/23212.0.188.1 to 212.0.189.254212.0.189.255510
96212.0.190.0/23212.0.190.1 to 212.0.191.254212.0.191.255510
97212.0.192.0/23212.0.192.1 to 212.0.193.254212.0.193.255510
98212.0.194.0/23212.0.194.1 to 212.0.195.254212.0.195.255510
99212.0.196.0/23212.0.196.1 to 212.0.197.254212.0.197.255510
100212.0.198.0/23212.0.198.1 to 212.0.199.254212.0.199.255510
101212.0.200.0/23212.0.200.1 to 212.0.201.254212.0.201.255510
102212.0.202.0/23212.0.202.1 to 212.0.203.254212.0.203.255510
103212.0.204.0/23212.0.204.1 to 212.0.205.254212.0.205.255510
104212.0.206.0/23212.0.206.1 to 212.0.207.254212.0.207.255510
105212.0.208.0/23212.0.208.1 to 212.0.209.254212.0.209.255510
106212.0.210.0/23212.0.210.1 to 212.0.211.254212.0.211.255510
107212.0.212.0/23212.0.212.1 to 212.0.213.254212.0.213.255510
108212.0.214.0/23212.0.214.1 to 212.0.215.254212.0.215.255510
109212.0.216.0/23212.0.216.1 to 212.0.217.254212.0.217.255510
110212.0.218.0/23212.0.218.1 to 212.0.219.254212.0.219.255510
111212.0.220.0/23212.0.220.1 to 212.0.221.254212.0.221.255510
112212.0.222.0/23212.0.222.1 to 212.0.223.254212.0.223.255510
113212.0.224.0/23212.0.224.1 to 212.0.225.254212.0.225.255510
114212.0.226.0/23212.0.226.1 to 212.0.227.254212.0.227.255510
115212.0.228.0/23212.0.228.1 to 212.0.229.254212.0.229.255510
116212.0.230.0/23212.0.230.1 to 212.0.231.254212.0.231.255510
117212.0.232.0/23212.0.232.1 to 212.0.233.254212.0.233.255510
118212.0.234.0/23212.0.234.1 to 212.0.235.254212.0.235.255510
119212.0.236.0/23212.0.236.1 to 212.0.237.254212.0.237.255510
120212.0.238.0/23212.0.238.1 to 212.0.239.254212.0.239.255510
121212.0.240.0/23212.0.240.1 to 212.0.241.254212.0.241.255510
122212.0.242.0/23212.0.242.1 to 212.0.243.254212.0.243.255510
123212.0.244.0/23212.0.244.1 to 212.0.245.254212.0.245.255510
124212.0.246.0/23212.0.246.1 to 212.0.247.254212.0.247.255510
125212.0.248.0/23212.0.248.1 to 212.0.249.254212.0.249.255510
126212.0.250.0/23212.0.250.1 to 212.0.251.254212.0.251.255510
127212.0.252.0/23212.0.252.1 to 212.0.253.254212.0.253.255510
128212.0.254.0/23212.0.254.1 to 212.0.255.254212.0.255.255510
129212.1.0.0/23212.1.0.1 to 212.1.1.254212.1.1.255510
130212.1.2.0/23212.1.2.1 to 212.1.3.254212.1.3.255510
131212.1.4.0/23212.1.4.1 to 212.1.5.254212.1.5.255510
132212.1.6.0/23212.1.6.1 to 212.1.7.254212.1.7.255510
133212.1.8.0/23212.1.8.1 to 212.1.9.254212.1.9.255510
134212.1.10.0/23212.1.10.1 to 212.1.11.254212.1.11.255510
135212.1.12.0/23212.1.12.1 to 212.1.13.254212.1.13.255510
136212.1.14.0/23212.1.14.1 to 212.1.15.254212.1.15.255510
137212.1.16.0/23212.1.16.1 to 212.1.17.254212.1.17.255510
138212.1.18.0/23212.1.18.1 to 212.1.19.254212.1.19.255510
139212.1.20.0/23212.1.20.1 to 212.1.21.254212.1.21.255510
140212.1.22.0/23212.1.22.1 to 212.1.23.254212.1.23.255510
141212.1.24.0/23212.1.24.1 to 212.1.25.254212.1.25.255510
142212.1.26.0/23212.1.26.1 to 212.1.27.254212.1.27.255510
143212.1.28.0/23212.1.28.1 to 212.1.29.254212.1.29.255510
144212.1.30.0/23212.1.30.1 to 212.1.31.254212.1.31.255510
145212.1.32.0/23212.1.32.1 to 212.1.33.254212.1.33.255510
146212.1.34.0/23212.1.34.1 to 212.1.35.254212.1.35.255510
147212.1.36.0/23212.1.36.1 to 212.1.37.254212.1.37.255510
148212.1.38.0/23212.1.38.1 to 212.1.39.254212.1.39.255510
149212.1.40.0/23212.1.40.1 to 212.1.41.254212.1.41.255510
150212.1.42.0/23212.1.42.1 to 212.1.43.254212.1.43.255510
151212.1.44.0/23212.1.44.1 to 212.1.45.254212.1.45.255510
152212.1.46.0/23212.1.46.1 to 212.1.47.254212.1.47.255510
153212.1.48.0/23212.1.48.1 to 212.1.49.254212.1.49.255510
154212.1.50.0/23212.1.50.1 to 212.1.51.254212.1.51.255510
155212.1.52.0/23212.1.52.1 to 212.1.53.254212.1.53.255510
156212.1.54.0/23212.1.54.1 to 212.1.55.254212.1.55.255510
157212.1.56.0/23212.1.56.1 to 212.1.57.254212.1.57.255510
158212.1.58.0/23212.1.58.1 to 212.1.59.254212.1.59.255510
159212.1.60.0/23212.1.60.1 to 212.1.61.254212.1.61.255510
160212.1.62.0/23212.1.62.1 to 212.1.63.254212.1.63.255510
161212.1.64.0/23212.1.64.1 to 212.1.65.254212.1.65.255510
162212.1.66.0/23212.1.66.1 to 212.1.67.254212.1.67.255510
163212.1.68.0/23212.1.68.1 to 212.1.69.254212.1.69.255510
164212.1.70.0/23212.1.70.1 to 212.1.71.254212.1.71.255510
165212.1.72.0/23212.1.72.1 to 212.1.73.254212.1.73.255510
166212.1.74.0/23212.1.74.1 to 212.1.75.254212.1.75.255510
167212.1.76.0/23212.1.76.1 to 212.1.77.254212.1.77.255510
168212.1.78.0/23212.1.78.1 to 212.1.79.254212.1.79.255510
169212.1.80.0/23212.1.80.1 to 212.1.81.254212.1.81.255510
170212.1.82.0/23212.1.82.1 to 212.1.83.254212.1.83.255510
171212.1.84.0/23212.1.84.1 to 212.1.85.254212.1.85.255510
172212.1.86.0/23212.1.86.1 to 212.1.87.254212.1.87.255510
173212.1.88.0/23212.1.88.1 to 212.1.89.254212.1.89.255510
174212.1.90.0/23212.1.90.1 to 212.1.91.254212.1.91.255510
175212.1.92.0/23212.1.92.1 to 212.1.93.254212.1.93.255510
176212.1.94.0/23212.1.94.1 to 212.1.95.254212.1.95.255510
177212.1.96.0/23212.1.96.1 to 212.1.97.254212.1.97.255510
178212.1.98.0/23212.1.98.1 to 212.1.99.254212.1.99.255510
179212.1.100.0/23212.1.100.1 to 212.1.101.254212.1.101.255510
180212.1.102.0/23212.1.102.1 to 212.1.103.254212.1.103.255510
181212.1.104.0/23212.1.104.1 to 212.1.105.254212.1.105.255510
182212.1.106.0/23212.1.106.1 to 212.1.107.254212.1.107.255510
183212.1.108.0/23212.1.108.1 to 212.1.109.254212.1.109.255510
184212.1.110.0/23212.1.110.1 to 212.1.111.254212.1.111.255510
185212.1.112.0/23212.1.112.1 to 212.1.113.254212.1.113.255510
186212.1.114.0/23212.1.114.1 to 212.1.115.254212.1.115.255510
187212.1.116.0/23212.1.116.1 to 212.1.117.254212.1.117.255510
188212.1.118.0/23212.1.118.1 to 212.1.119.254212.1.119.255510
189212.1.120.0/23212.1.120.1 to 212.1.121.254212.1.121.255510
190212.1.122.0/23212.1.122.1 to 212.1.123.254212.1.123.255510
191212.1.124.0/23212.1.124.1 to 212.1.125.254212.1.125.255510
192212.1.126.0/23212.1.126.1 to 212.1.127.254212.1.127.255510
193212.1.128.0/23212.1.128.1 to 212.1.129.254212.1.129.255510
194212.1.130.0/23212.1.130.1 to 212.1.131.254212.1.131.255510
195212.1.132.0/23212.1.132.1 to 212.1.133.254212.1.133.255510
196212.1.134.0/23212.1.134.1 to 212.1.135.254212.1.135.255510
197212.1.136.0/23212.1.136.1 to 212.1.137.254212.1.137.255510
198212.1.138.0/23212.1.138.1 to 212.1.139.254212.1.139.255510
199212.1.140.0/23212.1.140.1 to 212.1.141.254212.1.141.255510
200212.1.142.0/23212.1.142.1 to 212.1.143.254212.1.143.255510
201212.1.144.0/23212.1.144.1 to 212.1.145.254212.1.145.255510
202212.1.146.0/23212.1.146.1 to 212.1.147.254212.1.147.255510
203212.1.148.0/23212.1.148.1 to 212.1.149.254212.1.149.255510
204212.1.150.0/23212.1.150.1 to 212.1.151.254212.1.151.255510
205212.1.152.0/23212.1.152.1 to 212.1.153.254212.1.153.255510
206212.1.154.0/23212.1.154.1 to 212.1.155.254212.1.155.255510
207212.1.156.0/23212.1.156.1 to 212.1.157.254212.1.157.255510
208212.1.158.0/23212.1.158.1 to 212.1.159.254212.1.159.255510
209212.1.160.0/23212.1.160.1 to 212.1.161.254212.1.161.255510
210212.1.162.0/23212.1.162.1 to 212.1.163.254212.1.163.255510
211212.1.164.0/23212.1.164.1 to 212.1.165.254212.1.165.255510
212212.1.166.0/23212.1.166.1 to 212.1.167.254212.1.167.255510
213212.1.168.0/23212.1.168.1 to 212.1.169.254212.1.169.255510
214212.1.170.0/23212.1.170.1 to 212.1.171.254212.1.171.255510
215212.1.172.0/23212.1.172.1 to 212.1.173.254212.1.173.255510
216212.1.174.0/23212.1.174.1 to 212.1.175.254212.1.175.255510
217212.1.176.0/23212.1.176.1 to 212.1.177.254212.1.177.255510
218212.1.178.0/23212.1.178.1 to 212.1.179.254212.1.179.255510
219212.1.180.0/23212.1.180.1 to 212.1.181.254212.1.181.255510
220212.1.182.0/23212.1.182.1 to 212.1.183.254212.1.183.255510
221212.1.184.0/23212.1.184.1 to 212.1.185.254212.1.185.255510
222212.1.186.0/23212.1.186.1 to 212.1.187.254212.1.187.255510
223212.1.188.0/23212.1.188.1 to 212.1.189.254212.1.189.255510
224212.1.190.0/23212.1.190.1 to 212.1.191.254212.1.191.255510
225212.1.192.0/23212.1.192.1 to 212.1.193.254212.1.193.255510
226212.1.194.0/23212.1.194.1 to 212.1.195.254212.1.195.255510
227212.1.196.0/23212.1.196.1 to 212.1.197.254212.1.197.255510
228212.1.198.0/23212.1.198.1 to 212.1.199.254212.1.199.255510
229212.1.200.0/23212.1.200.1 to 212.1.201.254212.1.201.255510
230212.1.202.0/23212.1.202.1 to 212.1.203.254212.1.203.255510
231212.1.204.0/23212.1.204.1 to 212.1.205.254212.1.205.255510
232212.1.206.0/23212.1.206.1 to 212.1.207.254212.1.207.255510
233212.1.208.0/23212.1.208.1 to 212.1.209.254212.1.209.255510
234212.1.210.0/23212.1.210.1 to 212.1.211.254212.1.211.255510
235212.1.212.0/23212.1.212.1 to 212.1.213.254212.1.213.255510
236212.1.214.0/23212.1.214.1 to 212.1.215.254212.1.215.255510
237212.1.216.0/23212.1.216.1 to 212.1.217.254212.1.217.255510
238212.1.218.0/23212.1.218.1 to 212.1.219.254212.1.219.255510
239212.1.220.0/23212.1.220.1 to 212.1.221.254212.1.221.255510
240212.1.222.0/23212.1.222.1 to 212.1.223.254212.1.223.255510
241212.1.224.0/23212.1.224.1 to 212.1.225.254212.1.225.255510
242212.1.226.0/23212.1.226.1 to 212.1.227.254212.1.227.255510
243212.1.228.0/23212.1.228.1 to 212.1.229.254212.1.229.255510
244212.1.230.0/23212.1.230.1 to 212.1.231.254212.1.231.255510
245212.1.232.0/23212.1.232.1 to 212.1.233.254212.1.233.255510
246212.1.234.0/23212.1.234.1 to 212.1.235.254212.1.235.255510
247212.1.236.0/23212.1.236.1 to 212.1.237.254212.1.237.255510
248212.1.238.0/23212.1.238.1 to 212.1.239.254212.1.239.255510
249212.1.240.0/23212.1.240.1 to 212.1.241.254212.1.241.255510
250212.1.242.0/23212.1.242.1 to 212.1.243.254212.1.243.255510
251212.1.244.0/23212.1.244.1 to 212.1.245.254212.1.245.255510
252212.1.246.0/23212.1.246.1 to 212.1.247.254212.1.247.255510
253212.1.248.0/23212.1.248.1 to 212.1.249.254212.1.249.255510
254212.1.250.0/23212.1.250.1 to 212.1.251.254212.1.251.255510
255212.1.252.0/23212.1.252.1 to 212.1.253.254212.1.253.255510
256212.1.254.0/23212.1.254.1 to 212.1.255.254212.1.255.255510

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.