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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/18
/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 4,096 subnets of /18; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1212.0.0.0/18212.0.0.1 to 212.0.63.254212.0.63.25516,382
2212.0.64.0/18212.0.64.1 to 212.0.127.254212.0.127.25516,382
3212.0.128.0/18212.0.128.1 to 212.0.191.254212.0.191.25516,382
4212.0.192.0/18212.0.192.1 to 212.0.255.254212.0.255.25516,382
5212.1.0.0/18212.1.0.1 to 212.1.63.254212.1.63.25516,382
6212.1.64.0/18212.1.64.1 to 212.1.127.254212.1.127.25516,382
7212.1.128.0/18212.1.128.1 to 212.1.191.254212.1.191.25516,382
8212.1.192.0/18212.1.192.1 to 212.1.255.254212.1.255.25516,382
9212.2.0.0/18212.2.0.1 to 212.2.63.254212.2.63.25516,382
10212.2.64.0/18212.2.64.1 to 212.2.127.254212.2.127.25516,382
11212.2.128.0/18212.2.128.1 to 212.2.191.254212.2.191.25516,382
12212.2.192.0/18212.2.192.1 to 212.2.255.254212.2.255.25516,382
13212.3.0.0/18212.3.0.1 to 212.3.63.254212.3.63.25516,382
14212.3.64.0/18212.3.64.1 to 212.3.127.254212.3.127.25516,382
15212.3.128.0/18212.3.128.1 to 212.3.191.254212.3.191.25516,382
16212.3.192.0/18212.3.192.1 to 212.3.255.254212.3.255.25516,382
17212.4.0.0/18212.4.0.1 to 212.4.63.254212.4.63.25516,382
18212.4.64.0/18212.4.64.1 to 212.4.127.254212.4.127.25516,382
19212.4.128.0/18212.4.128.1 to 212.4.191.254212.4.191.25516,382
20212.4.192.0/18212.4.192.1 to 212.4.255.254212.4.255.25516,382
21212.5.0.0/18212.5.0.1 to 212.5.63.254212.5.63.25516,382
22212.5.64.0/18212.5.64.1 to 212.5.127.254212.5.127.25516,382
23212.5.128.0/18212.5.128.1 to 212.5.191.254212.5.191.25516,382
24212.5.192.0/18212.5.192.1 to 212.5.255.254212.5.255.25516,382
25212.6.0.0/18212.6.0.1 to 212.6.63.254212.6.63.25516,382
26212.6.64.0/18212.6.64.1 to 212.6.127.254212.6.127.25516,382
27212.6.128.0/18212.6.128.1 to 212.6.191.254212.6.191.25516,382
28212.6.192.0/18212.6.192.1 to 212.6.255.254212.6.255.25516,382
29212.7.0.0/18212.7.0.1 to 212.7.63.254212.7.63.25516,382
30212.7.64.0/18212.7.64.1 to 212.7.127.254212.7.127.25516,382
31212.7.128.0/18212.7.128.1 to 212.7.191.254212.7.191.25516,382
32212.7.192.0/18212.7.192.1 to 212.7.255.254212.7.255.25516,382
33212.8.0.0/18212.8.0.1 to 212.8.63.254212.8.63.25516,382
34212.8.64.0/18212.8.64.1 to 212.8.127.254212.8.127.25516,382
35212.8.128.0/18212.8.128.1 to 212.8.191.254212.8.191.25516,382
36212.8.192.0/18212.8.192.1 to 212.8.255.254212.8.255.25516,382
37212.9.0.0/18212.9.0.1 to 212.9.63.254212.9.63.25516,382
38212.9.64.0/18212.9.64.1 to 212.9.127.254212.9.127.25516,382
39212.9.128.0/18212.9.128.1 to 212.9.191.254212.9.191.25516,382
40212.9.192.0/18212.9.192.1 to 212.9.255.254212.9.255.25516,382
41212.10.0.0/18212.10.0.1 to 212.10.63.254212.10.63.25516,382
42212.10.64.0/18212.10.64.1 to 212.10.127.254212.10.127.25516,382
43212.10.128.0/18212.10.128.1 to 212.10.191.254212.10.191.25516,382
44212.10.192.0/18212.10.192.1 to 212.10.255.254212.10.255.25516,382
45212.11.0.0/18212.11.0.1 to 212.11.63.254212.11.63.25516,382
46212.11.64.0/18212.11.64.1 to 212.11.127.254212.11.127.25516,382
47212.11.128.0/18212.11.128.1 to 212.11.191.254212.11.191.25516,382
48212.11.192.0/18212.11.192.1 to 212.11.255.254212.11.255.25516,382
49212.12.0.0/18212.12.0.1 to 212.12.63.254212.12.63.25516,382
50212.12.64.0/18212.12.64.1 to 212.12.127.254212.12.127.25516,382
51212.12.128.0/18212.12.128.1 to 212.12.191.254212.12.191.25516,382
52212.12.192.0/18212.12.192.1 to 212.12.255.254212.12.255.25516,382
53212.13.0.0/18212.13.0.1 to 212.13.63.254212.13.63.25516,382
54212.13.64.0/18212.13.64.1 to 212.13.127.254212.13.127.25516,382
55212.13.128.0/18212.13.128.1 to 212.13.191.254212.13.191.25516,382
56212.13.192.0/18212.13.192.1 to 212.13.255.254212.13.255.25516,382
57212.14.0.0/18212.14.0.1 to 212.14.63.254212.14.63.25516,382
58212.14.64.0/18212.14.64.1 to 212.14.127.254212.14.127.25516,382
59212.14.128.0/18212.14.128.1 to 212.14.191.254212.14.191.25516,382
60212.14.192.0/18212.14.192.1 to 212.14.255.254212.14.255.25516,382
61212.15.0.0/18212.15.0.1 to 212.15.63.254212.15.63.25516,382
62212.15.64.0/18212.15.64.1 to 212.15.127.254212.15.127.25516,382
63212.15.128.0/18212.15.128.1 to 212.15.191.254212.15.191.25516,382
64212.15.192.0/18212.15.192.1 to 212.15.255.254212.15.255.25516,382
65212.16.0.0/18212.16.0.1 to 212.16.63.254212.16.63.25516,382
66212.16.64.0/18212.16.64.1 to 212.16.127.254212.16.127.25516,382
67212.16.128.0/18212.16.128.1 to 212.16.191.254212.16.191.25516,382
68212.16.192.0/18212.16.192.1 to 212.16.255.254212.16.255.25516,382
69212.17.0.0/18212.17.0.1 to 212.17.63.254212.17.63.25516,382
70212.17.64.0/18212.17.64.1 to 212.17.127.254212.17.127.25516,382
71212.17.128.0/18212.17.128.1 to 212.17.191.254212.17.191.25516,382
72212.17.192.0/18212.17.192.1 to 212.17.255.254212.17.255.25516,382
73212.18.0.0/18212.18.0.1 to 212.18.63.254212.18.63.25516,382
74212.18.64.0/18212.18.64.1 to 212.18.127.254212.18.127.25516,382
75212.18.128.0/18212.18.128.1 to 212.18.191.254212.18.191.25516,382
76212.18.192.0/18212.18.192.1 to 212.18.255.254212.18.255.25516,382
77212.19.0.0/18212.19.0.1 to 212.19.63.254212.19.63.25516,382
78212.19.64.0/18212.19.64.1 to 212.19.127.254212.19.127.25516,382
79212.19.128.0/18212.19.128.1 to 212.19.191.254212.19.191.25516,382
80212.19.192.0/18212.19.192.1 to 212.19.255.254212.19.255.25516,382
81212.20.0.0/18212.20.0.1 to 212.20.63.254212.20.63.25516,382
82212.20.64.0/18212.20.64.1 to 212.20.127.254212.20.127.25516,382
83212.20.128.0/18212.20.128.1 to 212.20.191.254212.20.191.25516,382
84212.20.192.0/18212.20.192.1 to 212.20.255.254212.20.255.25516,382
85212.21.0.0/18212.21.0.1 to 212.21.63.254212.21.63.25516,382
86212.21.64.0/18212.21.64.1 to 212.21.127.254212.21.127.25516,382
87212.21.128.0/18212.21.128.1 to 212.21.191.254212.21.191.25516,382
88212.21.192.0/18212.21.192.1 to 212.21.255.254212.21.255.25516,382
89212.22.0.0/18212.22.0.1 to 212.22.63.254212.22.63.25516,382
90212.22.64.0/18212.22.64.1 to 212.22.127.254212.22.127.25516,382
91212.22.128.0/18212.22.128.1 to 212.22.191.254212.22.191.25516,382
92212.22.192.0/18212.22.192.1 to 212.22.255.254212.22.255.25516,382
93212.23.0.0/18212.23.0.1 to 212.23.63.254212.23.63.25516,382
94212.23.64.0/18212.23.64.1 to 212.23.127.254212.23.127.25516,382
95212.23.128.0/18212.23.128.1 to 212.23.191.254212.23.191.25516,382
96212.23.192.0/18212.23.192.1 to 212.23.255.254212.23.255.25516,382
97212.24.0.0/18212.24.0.1 to 212.24.63.254212.24.63.25516,382
98212.24.64.0/18212.24.64.1 to 212.24.127.254212.24.127.25516,382
99212.24.128.0/18212.24.128.1 to 212.24.191.254212.24.191.25516,382
100212.24.192.0/18212.24.192.1 to 212.24.255.254212.24.255.25516,382
101212.25.0.0/18212.25.0.1 to 212.25.63.254212.25.63.25516,382
102212.25.64.0/18212.25.64.1 to 212.25.127.254212.25.127.25516,382
103212.25.128.0/18212.25.128.1 to 212.25.191.254212.25.191.25516,382
104212.25.192.0/18212.25.192.1 to 212.25.255.254212.25.255.25516,382
105212.26.0.0/18212.26.0.1 to 212.26.63.254212.26.63.25516,382
106212.26.64.0/18212.26.64.1 to 212.26.127.254212.26.127.25516,382
107212.26.128.0/18212.26.128.1 to 212.26.191.254212.26.191.25516,382
108212.26.192.0/18212.26.192.1 to 212.26.255.254212.26.255.25516,382
109212.27.0.0/18212.27.0.1 to 212.27.63.254212.27.63.25516,382
110212.27.64.0/18212.27.64.1 to 212.27.127.254212.27.127.25516,382
111212.27.128.0/18212.27.128.1 to 212.27.191.254212.27.191.25516,382
112212.27.192.0/18212.27.192.1 to 212.27.255.254212.27.255.25516,382
113212.28.0.0/18212.28.0.1 to 212.28.63.254212.28.63.25516,382
114212.28.64.0/18212.28.64.1 to 212.28.127.254212.28.127.25516,382
115212.28.128.0/18212.28.128.1 to 212.28.191.254212.28.191.25516,382
116212.28.192.0/18212.28.192.1 to 212.28.255.254212.28.255.25516,382
117212.29.0.0/18212.29.0.1 to 212.29.63.254212.29.63.25516,382
118212.29.64.0/18212.29.64.1 to 212.29.127.254212.29.127.25516,382
119212.29.128.0/18212.29.128.1 to 212.29.191.254212.29.191.25516,382
120212.29.192.0/18212.29.192.1 to 212.29.255.254212.29.255.25516,382
121212.30.0.0/18212.30.0.1 to 212.30.63.254212.30.63.25516,382
122212.30.64.0/18212.30.64.1 to 212.30.127.254212.30.127.25516,382
123212.30.128.0/18212.30.128.1 to 212.30.191.254212.30.191.25516,382
124212.30.192.0/18212.30.192.1 to 212.30.255.254212.30.255.25516,382
125212.31.0.0/18212.31.0.1 to 212.31.63.254212.31.63.25516,382
126212.31.64.0/18212.31.64.1 to 212.31.127.254212.31.127.25516,382
127212.31.128.0/18212.31.128.1 to 212.31.191.254212.31.191.25516,382
128212.31.192.0/18212.31.192.1 to 212.31.255.254212.31.255.25516,382
129212.32.0.0/18212.32.0.1 to 212.32.63.254212.32.63.25516,382
130212.32.64.0/18212.32.64.1 to 212.32.127.254212.32.127.25516,382
131212.32.128.0/18212.32.128.1 to 212.32.191.254212.32.191.25516,382
132212.32.192.0/18212.32.192.1 to 212.32.255.254212.32.255.25516,382
133212.33.0.0/18212.33.0.1 to 212.33.63.254212.33.63.25516,382
134212.33.64.0/18212.33.64.1 to 212.33.127.254212.33.127.25516,382
135212.33.128.0/18212.33.128.1 to 212.33.191.254212.33.191.25516,382
136212.33.192.0/18212.33.192.1 to 212.33.255.254212.33.255.25516,382
137212.34.0.0/18212.34.0.1 to 212.34.63.254212.34.63.25516,382
138212.34.64.0/18212.34.64.1 to 212.34.127.254212.34.127.25516,382
139212.34.128.0/18212.34.128.1 to 212.34.191.254212.34.191.25516,382
140212.34.192.0/18212.34.192.1 to 212.34.255.254212.34.255.25516,382
141212.35.0.0/18212.35.0.1 to 212.35.63.254212.35.63.25516,382
142212.35.64.0/18212.35.64.1 to 212.35.127.254212.35.127.25516,382
143212.35.128.0/18212.35.128.1 to 212.35.191.254212.35.191.25516,382
144212.35.192.0/18212.35.192.1 to 212.35.255.254212.35.255.25516,382
145212.36.0.0/18212.36.0.1 to 212.36.63.254212.36.63.25516,382
146212.36.64.0/18212.36.64.1 to 212.36.127.254212.36.127.25516,382
147212.36.128.0/18212.36.128.1 to 212.36.191.254212.36.191.25516,382
148212.36.192.0/18212.36.192.1 to 212.36.255.254212.36.255.25516,382
149212.37.0.0/18212.37.0.1 to 212.37.63.254212.37.63.25516,382
150212.37.64.0/18212.37.64.1 to 212.37.127.254212.37.127.25516,382
151212.37.128.0/18212.37.128.1 to 212.37.191.254212.37.191.25516,382
152212.37.192.0/18212.37.192.1 to 212.37.255.254212.37.255.25516,382
153212.38.0.0/18212.38.0.1 to 212.38.63.254212.38.63.25516,382
154212.38.64.0/18212.38.64.1 to 212.38.127.254212.38.127.25516,382
155212.38.128.0/18212.38.128.1 to 212.38.191.254212.38.191.25516,382
156212.38.192.0/18212.38.192.1 to 212.38.255.254212.38.255.25516,382
157212.39.0.0/18212.39.0.1 to 212.39.63.254212.39.63.25516,382
158212.39.64.0/18212.39.64.1 to 212.39.127.254212.39.127.25516,382
159212.39.128.0/18212.39.128.1 to 212.39.191.254212.39.191.25516,382
160212.39.192.0/18212.39.192.1 to 212.39.255.254212.39.255.25516,382
161212.40.0.0/18212.40.0.1 to 212.40.63.254212.40.63.25516,382
162212.40.64.0/18212.40.64.1 to 212.40.127.254212.40.127.25516,382
163212.40.128.0/18212.40.128.1 to 212.40.191.254212.40.191.25516,382
164212.40.192.0/18212.40.192.1 to 212.40.255.254212.40.255.25516,382
165212.41.0.0/18212.41.0.1 to 212.41.63.254212.41.63.25516,382
166212.41.64.0/18212.41.64.1 to 212.41.127.254212.41.127.25516,382
167212.41.128.0/18212.41.128.1 to 212.41.191.254212.41.191.25516,382
168212.41.192.0/18212.41.192.1 to 212.41.255.254212.41.255.25516,382
169212.42.0.0/18212.42.0.1 to 212.42.63.254212.42.63.25516,382
170212.42.64.0/18212.42.64.1 to 212.42.127.254212.42.127.25516,382
171212.42.128.0/18212.42.128.1 to 212.42.191.254212.42.191.25516,382
172212.42.192.0/18212.42.192.1 to 212.42.255.254212.42.255.25516,382
173212.43.0.0/18212.43.0.1 to 212.43.63.254212.43.63.25516,382
174212.43.64.0/18212.43.64.1 to 212.43.127.254212.43.127.25516,382
175212.43.128.0/18212.43.128.1 to 212.43.191.254212.43.191.25516,382
176212.43.192.0/18212.43.192.1 to 212.43.255.254212.43.255.25516,382
177212.44.0.0/18212.44.0.1 to 212.44.63.254212.44.63.25516,382
178212.44.64.0/18212.44.64.1 to 212.44.127.254212.44.127.25516,382
179212.44.128.0/18212.44.128.1 to 212.44.191.254212.44.191.25516,382
180212.44.192.0/18212.44.192.1 to 212.44.255.254212.44.255.25516,382
181212.45.0.0/18212.45.0.1 to 212.45.63.254212.45.63.25516,382
182212.45.64.0/18212.45.64.1 to 212.45.127.254212.45.127.25516,382
183212.45.128.0/18212.45.128.1 to 212.45.191.254212.45.191.25516,382
184212.45.192.0/18212.45.192.1 to 212.45.255.254212.45.255.25516,382
185212.46.0.0/18212.46.0.1 to 212.46.63.254212.46.63.25516,382
186212.46.64.0/18212.46.64.1 to 212.46.127.254212.46.127.25516,382
187212.46.128.0/18212.46.128.1 to 212.46.191.254212.46.191.25516,382
188212.46.192.0/18212.46.192.1 to 212.46.255.254212.46.255.25516,382
189212.47.0.0/18212.47.0.1 to 212.47.63.254212.47.63.25516,382
190212.47.64.0/18212.47.64.1 to 212.47.127.254212.47.127.25516,382
191212.47.128.0/18212.47.128.1 to 212.47.191.254212.47.191.25516,382
192212.47.192.0/18212.47.192.1 to 212.47.255.254212.47.255.25516,382
193212.48.0.0/18212.48.0.1 to 212.48.63.254212.48.63.25516,382
194212.48.64.0/18212.48.64.1 to 212.48.127.254212.48.127.25516,382
195212.48.128.0/18212.48.128.1 to 212.48.191.254212.48.191.25516,382
196212.48.192.0/18212.48.192.1 to 212.48.255.254212.48.255.25516,382
197212.49.0.0/18212.49.0.1 to 212.49.63.254212.49.63.25516,382
198212.49.64.0/18212.49.64.1 to 212.49.127.254212.49.127.25516,382
199212.49.128.0/18212.49.128.1 to 212.49.191.254212.49.191.25516,382
200212.49.192.0/18212.49.192.1 to 212.49.255.254212.49.255.25516,382
201212.50.0.0/18212.50.0.1 to 212.50.63.254212.50.63.25516,382
202212.50.64.0/18212.50.64.1 to 212.50.127.254212.50.127.25516,382
203212.50.128.0/18212.50.128.1 to 212.50.191.254212.50.191.25516,382
204212.50.192.0/18212.50.192.1 to 212.50.255.254212.50.255.25516,382
205212.51.0.0/18212.51.0.1 to 212.51.63.254212.51.63.25516,382
206212.51.64.0/18212.51.64.1 to 212.51.127.254212.51.127.25516,382
207212.51.128.0/18212.51.128.1 to 212.51.191.254212.51.191.25516,382
208212.51.192.0/18212.51.192.1 to 212.51.255.254212.51.255.25516,382
209212.52.0.0/18212.52.0.1 to 212.52.63.254212.52.63.25516,382
210212.52.64.0/18212.52.64.1 to 212.52.127.254212.52.127.25516,382
211212.52.128.0/18212.52.128.1 to 212.52.191.254212.52.191.25516,382
212212.52.192.0/18212.52.192.1 to 212.52.255.254212.52.255.25516,382
213212.53.0.0/18212.53.0.1 to 212.53.63.254212.53.63.25516,382
214212.53.64.0/18212.53.64.1 to 212.53.127.254212.53.127.25516,382
215212.53.128.0/18212.53.128.1 to 212.53.191.254212.53.191.25516,382
216212.53.192.0/18212.53.192.1 to 212.53.255.254212.53.255.25516,382
217212.54.0.0/18212.54.0.1 to 212.54.63.254212.54.63.25516,382
218212.54.64.0/18212.54.64.1 to 212.54.127.254212.54.127.25516,382
219212.54.128.0/18212.54.128.1 to 212.54.191.254212.54.191.25516,382
220212.54.192.0/18212.54.192.1 to 212.54.255.254212.54.255.25516,382
221212.55.0.0/18212.55.0.1 to 212.55.63.254212.55.63.25516,382
222212.55.64.0/18212.55.64.1 to 212.55.127.254212.55.127.25516,382
223212.55.128.0/18212.55.128.1 to 212.55.191.254212.55.191.25516,382
224212.55.192.0/18212.55.192.1 to 212.55.255.254212.55.255.25516,382
225212.56.0.0/18212.56.0.1 to 212.56.63.254212.56.63.25516,382
226212.56.64.0/18212.56.64.1 to 212.56.127.254212.56.127.25516,382
227212.56.128.0/18212.56.128.1 to 212.56.191.254212.56.191.25516,382
228212.56.192.0/18212.56.192.1 to 212.56.255.254212.56.255.25516,382
229212.57.0.0/18212.57.0.1 to 212.57.63.254212.57.63.25516,382
230212.57.64.0/18212.57.64.1 to 212.57.127.254212.57.127.25516,382
231212.57.128.0/18212.57.128.1 to 212.57.191.254212.57.191.25516,382
232212.57.192.0/18212.57.192.1 to 212.57.255.254212.57.255.25516,382
233212.58.0.0/18212.58.0.1 to 212.58.63.254212.58.63.25516,382
234212.58.64.0/18212.58.64.1 to 212.58.127.254212.58.127.25516,382
235212.58.128.0/18212.58.128.1 to 212.58.191.254212.58.191.25516,382
236212.58.192.0/18212.58.192.1 to 212.58.255.254212.58.255.25516,382
237212.59.0.0/18212.59.0.1 to 212.59.63.254212.59.63.25516,382
238212.59.64.0/18212.59.64.1 to 212.59.127.254212.59.127.25516,382
239212.59.128.0/18212.59.128.1 to 212.59.191.254212.59.191.25516,382
240212.59.192.0/18212.59.192.1 to 212.59.255.254212.59.255.25516,382
241212.60.0.0/18212.60.0.1 to 212.60.63.254212.60.63.25516,382
242212.60.64.0/18212.60.64.1 to 212.60.127.254212.60.127.25516,382
243212.60.128.0/18212.60.128.1 to 212.60.191.254212.60.191.25516,382
244212.60.192.0/18212.60.192.1 to 212.60.255.254212.60.255.25516,382
245212.61.0.0/18212.61.0.1 to 212.61.63.254212.61.63.25516,382
246212.61.64.0/18212.61.64.1 to 212.61.127.254212.61.127.25516,382
247212.61.128.0/18212.61.128.1 to 212.61.191.254212.61.191.25516,382
248212.61.192.0/18212.61.192.1 to 212.61.255.254212.61.255.25516,382
249212.62.0.0/18212.62.0.1 to 212.62.63.254212.62.63.25516,382
250212.62.64.0/18212.62.64.1 to 212.62.127.254212.62.127.25516,382
251212.62.128.0/18212.62.128.1 to 212.62.191.254212.62.191.25516,382
252212.62.192.0/18212.62.192.1 to 212.62.255.254212.62.255.25516,382
253212.63.0.0/18212.63.0.1 to 212.63.63.254212.63.63.25516,382
254212.63.64.0/18212.63.64.1 to 212.63.127.254212.63.127.25516,382
255212.63.128.0/18212.63.128.1 to 212.63.191.254212.63.191.25516,382
256212.63.192.0/18212.63.192.1 to 212.63.255.254212.63.255.25516,382

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.