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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.

Network212.0.0.0/6
Usable hosts67,108,862
Subnet mask252.0.0.0
Addresses67,108,864
Network address
212.0.0.0
Broadcast address
215.255.255.255
First usable
212.0.0.1
Last usable
215.255.255.254
Usable hosts
67,108,862 (67,108,864 less the network and broadcast addresses)
Subnet mask
252.0.0.0
Wildcard mask
3.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/6
Type
Public public
Old class
C (default /24)
As numbers
Hex D4000000 · Integer 3556769792 to 3623878655
Reverse DNS zones
212.in-addr.arpa
213.in-addr.arpa
214.in-addr.arpa
215.in-addr.arpa
/6 is not on a 8-bit boundary, so it takes 4 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11010100.00000000.00000000.00000000212.0.0.0
Subnet mask11111100.00000000.00000000.00000000252.0.0.0
Network11010100.00000000.00000000.00000000212.0.0.0
Broadcast11010111.11111111.11111111.11111111215.255.255.255
Split into smaller subnets/16
/7 (2)/8 (4)/9 (8)/10 (16)/11 (32)/12 (64)/13 (128)/14 (256)/15 (512)/16 (1,024)/17 (2,048)/18 (4,096)

212.0.0.0/6 makes 1,024 subnets of /16; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1212.0.0.0/16212.0.0.1 to 212.0.255.254212.0.255.25565,534
2212.1.0.0/16212.1.0.1 to 212.1.255.254212.1.255.25565,534
3212.2.0.0/16212.2.0.1 to 212.2.255.254212.2.255.25565,534
4212.3.0.0/16212.3.0.1 to 212.3.255.254212.3.255.25565,534
5212.4.0.0/16212.4.0.1 to 212.4.255.254212.4.255.25565,534
6212.5.0.0/16212.5.0.1 to 212.5.255.254212.5.255.25565,534
7212.6.0.0/16212.6.0.1 to 212.6.255.254212.6.255.25565,534
8212.7.0.0/16212.7.0.1 to 212.7.255.254212.7.255.25565,534
9212.8.0.0/16212.8.0.1 to 212.8.255.254212.8.255.25565,534
10212.9.0.0/16212.9.0.1 to 212.9.255.254212.9.255.25565,534
11212.10.0.0/16212.10.0.1 to 212.10.255.254212.10.255.25565,534
12212.11.0.0/16212.11.0.1 to 212.11.255.254212.11.255.25565,534
13212.12.0.0/16212.12.0.1 to 212.12.255.254212.12.255.25565,534
14212.13.0.0/16212.13.0.1 to 212.13.255.254212.13.255.25565,534
15212.14.0.0/16212.14.0.1 to 212.14.255.254212.14.255.25565,534
16212.15.0.0/16212.15.0.1 to 212.15.255.254212.15.255.25565,534
17212.16.0.0/16212.16.0.1 to 212.16.255.254212.16.255.25565,534
18212.17.0.0/16212.17.0.1 to 212.17.255.254212.17.255.25565,534
19212.18.0.0/16212.18.0.1 to 212.18.255.254212.18.255.25565,534
20212.19.0.0/16212.19.0.1 to 212.19.255.254212.19.255.25565,534
21212.20.0.0/16212.20.0.1 to 212.20.255.254212.20.255.25565,534
22212.21.0.0/16212.21.0.1 to 212.21.255.254212.21.255.25565,534
23212.22.0.0/16212.22.0.1 to 212.22.255.254212.22.255.25565,534
24212.23.0.0/16212.23.0.1 to 212.23.255.254212.23.255.25565,534
25212.24.0.0/16212.24.0.1 to 212.24.255.254212.24.255.25565,534
26212.25.0.0/16212.25.0.1 to 212.25.255.254212.25.255.25565,534
27212.26.0.0/16212.26.0.1 to 212.26.255.254212.26.255.25565,534
28212.27.0.0/16212.27.0.1 to 212.27.255.254212.27.255.25565,534
29212.28.0.0/16212.28.0.1 to 212.28.255.254212.28.255.25565,534
30212.29.0.0/16212.29.0.1 to 212.29.255.254212.29.255.25565,534
31212.30.0.0/16212.30.0.1 to 212.30.255.254212.30.255.25565,534
32212.31.0.0/16212.31.0.1 to 212.31.255.254212.31.255.25565,534
33212.32.0.0/16212.32.0.1 to 212.32.255.254212.32.255.25565,534
34212.33.0.0/16212.33.0.1 to 212.33.255.254212.33.255.25565,534
35212.34.0.0/16212.34.0.1 to 212.34.255.254212.34.255.25565,534
36212.35.0.0/16212.35.0.1 to 212.35.255.254212.35.255.25565,534
37212.36.0.0/16212.36.0.1 to 212.36.255.254212.36.255.25565,534
38212.37.0.0/16212.37.0.1 to 212.37.255.254212.37.255.25565,534
39212.38.0.0/16212.38.0.1 to 212.38.255.254212.38.255.25565,534
40212.39.0.0/16212.39.0.1 to 212.39.255.254212.39.255.25565,534
41212.40.0.0/16212.40.0.1 to 212.40.255.254212.40.255.25565,534
42212.41.0.0/16212.41.0.1 to 212.41.255.254212.41.255.25565,534
43212.42.0.0/16212.42.0.1 to 212.42.255.254212.42.255.25565,534
44212.43.0.0/16212.43.0.1 to 212.43.255.254212.43.255.25565,534
45212.44.0.0/16212.44.0.1 to 212.44.255.254212.44.255.25565,534
46212.45.0.0/16212.45.0.1 to 212.45.255.254212.45.255.25565,534
47212.46.0.0/16212.46.0.1 to 212.46.255.254212.46.255.25565,534
48212.47.0.0/16212.47.0.1 to 212.47.255.254212.47.255.25565,534
49212.48.0.0/16212.48.0.1 to 212.48.255.254212.48.255.25565,534
50212.49.0.0/16212.49.0.1 to 212.49.255.254212.49.255.25565,534
51212.50.0.0/16212.50.0.1 to 212.50.255.254212.50.255.25565,534
52212.51.0.0/16212.51.0.1 to 212.51.255.254212.51.255.25565,534
53212.52.0.0/16212.52.0.1 to 212.52.255.254212.52.255.25565,534
54212.53.0.0/16212.53.0.1 to 212.53.255.254212.53.255.25565,534
55212.54.0.0/16212.54.0.1 to 212.54.255.254212.54.255.25565,534
56212.55.0.0/16212.55.0.1 to 212.55.255.254212.55.255.25565,534
57212.56.0.0/16212.56.0.1 to 212.56.255.254212.56.255.25565,534
58212.57.0.0/16212.57.0.1 to 212.57.255.254212.57.255.25565,534
59212.58.0.0/16212.58.0.1 to 212.58.255.254212.58.255.25565,534
60212.59.0.0/16212.59.0.1 to 212.59.255.254212.59.255.25565,534
61212.60.0.0/16212.60.0.1 to 212.60.255.254212.60.255.25565,534
62212.61.0.0/16212.61.0.1 to 212.61.255.254212.61.255.25565,534
63212.62.0.0/16212.62.0.1 to 212.62.255.254212.62.255.25565,534
64212.63.0.0/16212.63.0.1 to 212.63.255.254212.63.255.25565,534
65212.64.0.0/16212.64.0.1 to 212.64.255.254212.64.255.25565,534
66212.65.0.0/16212.65.0.1 to 212.65.255.254212.65.255.25565,534
67212.66.0.0/16212.66.0.1 to 212.66.255.254212.66.255.25565,534
68212.67.0.0/16212.67.0.1 to 212.67.255.254212.67.255.25565,534
69212.68.0.0/16212.68.0.1 to 212.68.255.254212.68.255.25565,534
70212.69.0.0/16212.69.0.1 to 212.69.255.254212.69.255.25565,534
71212.70.0.0/16212.70.0.1 to 212.70.255.254212.70.255.25565,534
72212.71.0.0/16212.71.0.1 to 212.71.255.254212.71.255.25565,534
73212.72.0.0/16212.72.0.1 to 212.72.255.254212.72.255.25565,534
74212.73.0.0/16212.73.0.1 to 212.73.255.254212.73.255.25565,534
75212.74.0.0/16212.74.0.1 to 212.74.255.254212.74.255.25565,534
76212.75.0.0/16212.75.0.1 to 212.75.255.254212.75.255.25565,534
77212.76.0.0/16212.76.0.1 to 212.76.255.254212.76.255.25565,534
78212.77.0.0/16212.77.0.1 to 212.77.255.254212.77.255.25565,534
79212.78.0.0/16212.78.0.1 to 212.78.255.254212.78.255.25565,534
80212.79.0.0/16212.79.0.1 to 212.79.255.254212.79.255.25565,534
81212.80.0.0/16212.80.0.1 to 212.80.255.254212.80.255.25565,534
82212.81.0.0/16212.81.0.1 to 212.81.255.254212.81.255.25565,534
83212.82.0.0/16212.82.0.1 to 212.82.255.254212.82.255.25565,534
84212.83.0.0/16212.83.0.1 to 212.83.255.254212.83.255.25565,534
85212.84.0.0/16212.84.0.1 to 212.84.255.254212.84.255.25565,534
86212.85.0.0/16212.85.0.1 to 212.85.255.254212.85.255.25565,534
87212.86.0.0/16212.86.0.1 to 212.86.255.254212.86.255.25565,534
88212.87.0.0/16212.87.0.1 to 212.87.255.254212.87.255.25565,534
89212.88.0.0/16212.88.0.1 to 212.88.255.254212.88.255.25565,534
90212.89.0.0/16212.89.0.1 to 212.89.255.254212.89.255.25565,534
91212.90.0.0/16212.90.0.1 to 212.90.255.254212.90.255.25565,534
92212.91.0.0/16212.91.0.1 to 212.91.255.254212.91.255.25565,534
93212.92.0.0/16212.92.0.1 to 212.92.255.254212.92.255.25565,534
94212.93.0.0/16212.93.0.1 to 212.93.255.254212.93.255.25565,534
95212.94.0.0/16212.94.0.1 to 212.94.255.254212.94.255.25565,534
96212.95.0.0/16212.95.0.1 to 212.95.255.254212.95.255.25565,534
97212.96.0.0/16212.96.0.1 to 212.96.255.254212.96.255.25565,534
98212.97.0.0/16212.97.0.1 to 212.97.255.254212.97.255.25565,534
99212.98.0.0/16212.98.0.1 to 212.98.255.254212.98.255.25565,534
100212.99.0.0/16212.99.0.1 to 212.99.255.254212.99.255.25565,534
101212.100.0.0/16212.100.0.1 to 212.100.255.254212.100.255.25565,534
102212.101.0.0/16212.101.0.1 to 212.101.255.254212.101.255.25565,534
103212.102.0.0/16212.102.0.1 to 212.102.255.254212.102.255.25565,534
104212.103.0.0/16212.103.0.1 to 212.103.255.254212.103.255.25565,534
105212.104.0.0/16212.104.0.1 to 212.104.255.254212.104.255.25565,534
106212.105.0.0/16212.105.0.1 to 212.105.255.254212.105.255.25565,534
107212.106.0.0/16212.106.0.1 to 212.106.255.254212.106.255.25565,534
108212.107.0.0/16212.107.0.1 to 212.107.255.254212.107.255.25565,534
109212.108.0.0/16212.108.0.1 to 212.108.255.254212.108.255.25565,534
110212.109.0.0/16212.109.0.1 to 212.109.255.254212.109.255.25565,534
111212.110.0.0/16212.110.0.1 to 212.110.255.254212.110.255.25565,534
112212.111.0.0/16212.111.0.1 to 212.111.255.254212.111.255.25565,534
113212.112.0.0/16212.112.0.1 to 212.112.255.254212.112.255.25565,534
114212.113.0.0/16212.113.0.1 to 212.113.255.254212.113.255.25565,534
115212.114.0.0/16212.114.0.1 to 212.114.255.254212.114.255.25565,534
116212.115.0.0/16212.115.0.1 to 212.115.255.254212.115.255.25565,534
117212.116.0.0/16212.116.0.1 to 212.116.255.254212.116.255.25565,534
118212.117.0.0/16212.117.0.1 to 212.117.255.254212.117.255.25565,534
119212.118.0.0/16212.118.0.1 to 212.118.255.254212.118.255.25565,534
120212.119.0.0/16212.119.0.1 to 212.119.255.254212.119.255.25565,534
121212.120.0.0/16212.120.0.1 to 212.120.255.254212.120.255.25565,534
122212.121.0.0/16212.121.0.1 to 212.121.255.254212.121.255.25565,534
123212.122.0.0/16212.122.0.1 to 212.122.255.254212.122.255.25565,534
124212.123.0.0/16212.123.0.1 to 212.123.255.254212.123.255.25565,534
125212.124.0.0/16212.124.0.1 to 212.124.255.254212.124.255.25565,534
126212.125.0.0/16212.125.0.1 to 212.125.255.254212.125.255.25565,534
127212.126.0.0/16212.126.0.1 to 212.126.255.254212.126.255.25565,534
128212.127.0.0/16212.127.0.1 to 212.127.255.254212.127.255.25565,534
129212.128.0.0/16212.128.0.1 to 212.128.255.254212.128.255.25565,534
130212.129.0.0/16212.129.0.1 to 212.129.255.254212.129.255.25565,534
131212.130.0.0/16212.130.0.1 to 212.130.255.254212.130.255.25565,534
132212.131.0.0/16212.131.0.1 to 212.131.255.254212.131.255.25565,534
133212.132.0.0/16212.132.0.1 to 212.132.255.254212.132.255.25565,534
134212.133.0.0/16212.133.0.1 to 212.133.255.254212.133.255.25565,534
135212.134.0.0/16212.134.0.1 to 212.134.255.254212.134.255.25565,534
136212.135.0.0/16212.135.0.1 to 212.135.255.254212.135.255.25565,534
137212.136.0.0/16212.136.0.1 to 212.136.255.254212.136.255.25565,534
138212.137.0.0/16212.137.0.1 to 212.137.255.254212.137.255.25565,534
139212.138.0.0/16212.138.0.1 to 212.138.255.254212.138.255.25565,534
140212.139.0.0/16212.139.0.1 to 212.139.255.254212.139.255.25565,534
141212.140.0.0/16212.140.0.1 to 212.140.255.254212.140.255.25565,534
142212.141.0.0/16212.141.0.1 to 212.141.255.254212.141.255.25565,534
143212.142.0.0/16212.142.0.1 to 212.142.255.254212.142.255.25565,534
144212.143.0.0/16212.143.0.1 to 212.143.255.254212.143.255.25565,534
145212.144.0.0/16212.144.0.1 to 212.144.255.254212.144.255.25565,534
146212.145.0.0/16212.145.0.1 to 212.145.255.254212.145.255.25565,534
147212.146.0.0/16212.146.0.1 to 212.146.255.254212.146.255.25565,534
148212.147.0.0/16212.147.0.1 to 212.147.255.254212.147.255.25565,534
149212.148.0.0/16212.148.0.1 to 212.148.255.254212.148.255.25565,534
150212.149.0.0/16212.149.0.1 to 212.149.255.254212.149.255.25565,534
151212.150.0.0/16212.150.0.1 to 212.150.255.254212.150.255.25565,534
152212.151.0.0/16212.151.0.1 to 212.151.255.254212.151.255.25565,534
153212.152.0.0/16212.152.0.1 to 212.152.255.254212.152.255.25565,534
154212.153.0.0/16212.153.0.1 to 212.153.255.254212.153.255.25565,534
155212.154.0.0/16212.154.0.1 to 212.154.255.254212.154.255.25565,534
156212.155.0.0/16212.155.0.1 to 212.155.255.254212.155.255.25565,534
157212.156.0.0/16212.156.0.1 to 212.156.255.254212.156.255.25565,534
158212.157.0.0/16212.157.0.1 to 212.157.255.254212.157.255.25565,534
159212.158.0.0/16212.158.0.1 to 212.158.255.254212.158.255.25565,534
160212.159.0.0/16212.159.0.1 to 212.159.255.254212.159.255.25565,534
161212.160.0.0/16212.160.0.1 to 212.160.255.254212.160.255.25565,534
162212.161.0.0/16212.161.0.1 to 212.161.255.254212.161.255.25565,534
163212.162.0.0/16212.162.0.1 to 212.162.255.254212.162.255.25565,534
164212.163.0.0/16212.163.0.1 to 212.163.255.254212.163.255.25565,534
165212.164.0.0/16212.164.0.1 to 212.164.255.254212.164.255.25565,534
166212.165.0.0/16212.165.0.1 to 212.165.255.254212.165.255.25565,534
167212.166.0.0/16212.166.0.1 to 212.166.255.254212.166.255.25565,534
168212.167.0.0/16212.167.0.1 to 212.167.255.254212.167.255.25565,534
169212.168.0.0/16212.168.0.1 to 212.168.255.254212.168.255.25565,534
170212.169.0.0/16212.169.0.1 to 212.169.255.254212.169.255.25565,534
171212.170.0.0/16212.170.0.1 to 212.170.255.254212.170.255.25565,534
172212.171.0.0/16212.171.0.1 to 212.171.255.254212.171.255.25565,534
173212.172.0.0/16212.172.0.1 to 212.172.255.254212.172.255.25565,534
174212.173.0.0/16212.173.0.1 to 212.173.255.254212.173.255.25565,534
175212.174.0.0/16212.174.0.1 to 212.174.255.254212.174.255.25565,534
176212.175.0.0/16212.175.0.1 to 212.175.255.254212.175.255.25565,534
177212.176.0.0/16212.176.0.1 to 212.176.255.254212.176.255.25565,534
178212.177.0.0/16212.177.0.1 to 212.177.255.254212.177.255.25565,534
179212.178.0.0/16212.178.0.1 to 212.178.255.254212.178.255.25565,534
180212.179.0.0/16212.179.0.1 to 212.179.255.254212.179.255.25565,534
181212.180.0.0/16212.180.0.1 to 212.180.255.254212.180.255.25565,534
182212.181.0.0/16212.181.0.1 to 212.181.255.254212.181.255.25565,534
183212.182.0.0/16212.182.0.1 to 212.182.255.254212.182.255.25565,534
184212.183.0.0/16212.183.0.1 to 212.183.255.254212.183.255.25565,534
185212.184.0.0/16212.184.0.1 to 212.184.255.254212.184.255.25565,534
186212.185.0.0/16212.185.0.1 to 212.185.255.254212.185.255.25565,534
187212.186.0.0/16212.186.0.1 to 212.186.255.254212.186.255.25565,534
188212.187.0.0/16212.187.0.1 to 212.187.255.254212.187.255.25565,534
189212.188.0.0/16212.188.0.1 to 212.188.255.254212.188.255.25565,534
190212.189.0.0/16212.189.0.1 to 212.189.255.254212.189.255.25565,534
191212.190.0.0/16212.190.0.1 to 212.190.255.254212.190.255.25565,534
192212.191.0.0/16212.191.0.1 to 212.191.255.254212.191.255.25565,534
193212.192.0.0/16212.192.0.1 to 212.192.255.254212.192.255.25565,534
194212.193.0.0/16212.193.0.1 to 212.193.255.254212.193.255.25565,534
195212.194.0.0/16212.194.0.1 to 212.194.255.254212.194.255.25565,534
196212.195.0.0/16212.195.0.1 to 212.195.255.254212.195.255.25565,534
197212.196.0.0/16212.196.0.1 to 212.196.255.254212.196.255.25565,534
198212.197.0.0/16212.197.0.1 to 212.197.255.254212.197.255.25565,534
199212.198.0.0/16212.198.0.1 to 212.198.255.254212.198.255.25565,534
200212.199.0.0/16212.199.0.1 to 212.199.255.254212.199.255.25565,534
201212.200.0.0/16212.200.0.1 to 212.200.255.254212.200.255.25565,534
202212.201.0.0/16212.201.0.1 to 212.201.255.254212.201.255.25565,534
203212.202.0.0/16212.202.0.1 to 212.202.255.254212.202.255.25565,534
204212.203.0.0/16212.203.0.1 to 212.203.255.254212.203.255.25565,534
205212.204.0.0/16212.204.0.1 to 212.204.255.254212.204.255.25565,534
206212.205.0.0/16212.205.0.1 to 212.205.255.254212.205.255.25565,534
207212.206.0.0/16212.206.0.1 to 212.206.255.254212.206.255.25565,534
208212.207.0.0/16212.207.0.1 to 212.207.255.254212.207.255.25565,534
209212.208.0.0/16212.208.0.1 to 212.208.255.254212.208.255.25565,534
210212.209.0.0/16212.209.0.1 to 212.209.255.254212.209.255.25565,534
211212.210.0.0/16212.210.0.1 to 212.210.255.254212.210.255.25565,534
212212.211.0.0/16212.211.0.1 to 212.211.255.254212.211.255.25565,534
213212.212.0.0/16212.212.0.1 to 212.212.255.254212.212.255.25565,534
214212.213.0.0/16212.213.0.1 to 212.213.255.254212.213.255.25565,534
215212.214.0.0/16212.214.0.1 to 212.214.255.254212.214.255.25565,534
216212.215.0.0/16212.215.0.1 to 212.215.255.254212.215.255.25565,534
217212.216.0.0/16212.216.0.1 to 212.216.255.254212.216.255.25565,534
218212.217.0.0/16212.217.0.1 to 212.217.255.254212.217.255.25565,534
219212.218.0.0/16212.218.0.1 to 212.218.255.254212.218.255.25565,534
220212.219.0.0/16212.219.0.1 to 212.219.255.254212.219.255.25565,534
221212.220.0.0/16212.220.0.1 to 212.220.255.254212.220.255.25565,534
222212.221.0.0/16212.221.0.1 to 212.221.255.254212.221.255.25565,534
223212.222.0.0/16212.222.0.1 to 212.222.255.254212.222.255.25565,534
224212.223.0.0/16212.223.0.1 to 212.223.255.254212.223.255.25565,534
225212.224.0.0/16212.224.0.1 to 212.224.255.254212.224.255.25565,534
226212.225.0.0/16212.225.0.1 to 212.225.255.254212.225.255.25565,534
227212.226.0.0/16212.226.0.1 to 212.226.255.254212.226.255.25565,534
228212.227.0.0/16212.227.0.1 to 212.227.255.254212.227.255.25565,534
229212.228.0.0/16212.228.0.1 to 212.228.255.254212.228.255.25565,534
230212.229.0.0/16212.229.0.1 to 212.229.255.254212.229.255.25565,534
231212.230.0.0/16212.230.0.1 to 212.230.255.254212.230.255.25565,534
232212.231.0.0/16212.231.0.1 to 212.231.255.254212.231.255.25565,534
233212.232.0.0/16212.232.0.1 to 212.232.255.254212.232.255.25565,534
234212.233.0.0/16212.233.0.1 to 212.233.255.254212.233.255.25565,534
235212.234.0.0/16212.234.0.1 to 212.234.255.254212.234.255.25565,534
236212.235.0.0/16212.235.0.1 to 212.235.255.254212.235.255.25565,534
237212.236.0.0/16212.236.0.1 to 212.236.255.254212.236.255.25565,534
238212.237.0.0/16212.237.0.1 to 212.237.255.254212.237.255.25565,534
239212.238.0.0/16212.238.0.1 to 212.238.255.254212.238.255.25565,534
240212.239.0.0/16212.239.0.1 to 212.239.255.254212.239.255.25565,534
241212.240.0.0/16212.240.0.1 to 212.240.255.254212.240.255.25565,534
242212.241.0.0/16212.241.0.1 to 212.241.255.254212.241.255.25565,534
243212.242.0.0/16212.242.0.1 to 212.242.255.254212.242.255.25565,534
244212.243.0.0/16212.243.0.1 to 212.243.255.254212.243.255.25565,534
245212.244.0.0/16212.244.0.1 to 212.244.255.254212.244.255.25565,534
246212.245.0.0/16212.245.0.1 to 212.245.255.254212.245.255.25565,534
247212.246.0.0/16212.246.0.1 to 212.246.255.254212.246.255.25565,534
248212.247.0.0/16212.247.0.1 to 212.247.255.254212.247.255.25565,534
249212.248.0.0/16212.248.0.1 to 212.248.255.254212.248.255.25565,534
250212.249.0.0/16212.249.0.1 to 212.249.255.254212.249.255.25565,534
251212.250.0.0/16212.250.0.1 to 212.250.255.254212.250.255.25565,534
252212.251.0.0/16212.251.0.1 to 212.251.255.254212.251.255.25565,534
253212.252.0.0/16212.252.0.1 to 212.252.255.254212.252.255.25565,534
254212.253.0.0/16212.253.0.1 to 212.253.255.254212.253.255.25565,534
255212.254.0.0/16212.254.0.1 to 212.254.255.254212.254.255.25565,534
256212.255.0.0/16212.255.0.1 to 212.255.255.254212.255.255.25565,534

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.