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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.

Network212.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
212.0.0.0
Broadcast address
212.255.255.255
First usable
212.0.0.1
Last usable
212.255.255.254
Usable hosts
16,777,214 (16,777,216 less the network and broadcast addresses)
Subnet mask
255.0.0.0
Wildcard mask
0.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/8
Type
Public public
Old class
C (default /24)
As numbers
Hex D4000000 · Integer 3556769792 to 3573547007
Reverse DNS zone
212.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11010100..00000000.00000000.00000000212.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network11010100..00000000.00000000.00000000212.0.0.0
Broadcast11010100..11111111.11111111.11111111212.255.255.255
Split into smaller subnets/17
/9 (2)/10 (4)/11 (8)/12 (16)/13 (32)/14 (64)/15 (128)/16 (256)/17 (512)/18 (1,024)/19 (2,048)/20 (4,096)

212.0.0.0/8 makes 512 subnets of /17; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1212.0.0.0/17212.0.0.1 to 212.0.127.254212.0.127.25532,766
2212.0.128.0/17212.0.128.1 to 212.0.255.254212.0.255.25532,766
3212.1.0.0/17212.1.0.1 to 212.1.127.254212.1.127.25532,766
4212.1.128.0/17212.1.128.1 to 212.1.255.254212.1.255.25532,766
5212.2.0.0/17212.2.0.1 to 212.2.127.254212.2.127.25532,766
6212.2.128.0/17212.2.128.1 to 212.2.255.254212.2.255.25532,766
7212.3.0.0/17212.3.0.1 to 212.3.127.254212.3.127.25532,766
8212.3.128.0/17212.3.128.1 to 212.3.255.254212.3.255.25532,766
9212.4.0.0/17212.4.0.1 to 212.4.127.254212.4.127.25532,766
10212.4.128.0/17212.4.128.1 to 212.4.255.254212.4.255.25532,766
11212.5.0.0/17212.5.0.1 to 212.5.127.254212.5.127.25532,766
12212.5.128.0/17212.5.128.1 to 212.5.255.254212.5.255.25532,766
13212.6.0.0/17212.6.0.1 to 212.6.127.254212.6.127.25532,766
14212.6.128.0/17212.6.128.1 to 212.6.255.254212.6.255.25532,766
15212.7.0.0/17212.7.0.1 to 212.7.127.254212.7.127.25532,766
16212.7.128.0/17212.7.128.1 to 212.7.255.254212.7.255.25532,766
17212.8.0.0/17212.8.0.1 to 212.8.127.254212.8.127.25532,766
18212.8.128.0/17212.8.128.1 to 212.8.255.254212.8.255.25532,766
19212.9.0.0/17212.9.0.1 to 212.9.127.254212.9.127.25532,766
20212.9.128.0/17212.9.128.1 to 212.9.255.254212.9.255.25532,766
21212.10.0.0/17212.10.0.1 to 212.10.127.254212.10.127.25532,766
22212.10.128.0/17212.10.128.1 to 212.10.255.254212.10.255.25532,766
23212.11.0.0/17212.11.0.1 to 212.11.127.254212.11.127.25532,766
24212.11.128.0/17212.11.128.1 to 212.11.255.254212.11.255.25532,766
25212.12.0.0/17212.12.0.1 to 212.12.127.254212.12.127.25532,766
26212.12.128.0/17212.12.128.1 to 212.12.255.254212.12.255.25532,766
27212.13.0.0/17212.13.0.1 to 212.13.127.254212.13.127.25532,766
28212.13.128.0/17212.13.128.1 to 212.13.255.254212.13.255.25532,766
29212.14.0.0/17212.14.0.1 to 212.14.127.254212.14.127.25532,766
30212.14.128.0/17212.14.128.1 to 212.14.255.254212.14.255.25532,766
31212.15.0.0/17212.15.0.1 to 212.15.127.254212.15.127.25532,766
32212.15.128.0/17212.15.128.1 to 212.15.255.254212.15.255.25532,766
33212.16.0.0/17212.16.0.1 to 212.16.127.254212.16.127.25532,766
34212.16.128.0/17212.16.128.1 to 212.16.255.254212.16.255.25532,766
35212.17.0.0/17212.17.0.1 to 212.17.127.254212.17.127.25532,766
36212.17.128.0/17212.17.128.1 to 212.17.255.254212.17.255.25532,766
37212.18.0.0/17212.18.0.1 to 212.18.127.254212.18.127.25532,766
38212.18.128.0/17212.18.128.1 to 212.18.255.254212.18.255.25532,766
39212.19.0.0/17212.19.0.1 to 212.19.127.254212.19.127.25532,766
40212.19.128.0/17212.19.128.1 to 212.19.255.254212.19.255.25532,766
41212.20.0.0/17212.20.0.1 to 212.20.127.254212.20.127.25532,766
42212.20.128.0/17212.20.128.1 to 212.20.255.254212.20.255.25532,766
43212.21.0.0/17212.21.0.1 to 212.21.127.254212.21.127.25532,766
44212.21.128.0/17212.21.128.1 to 212.21.255.254212.21.255.25532,766
45212.22.0.0/17212.22.0.1 to 212.22.127.254212.22.127.25532,766
46212.22.128.0/17212.22.128.1 to 212.22.255.254212.22.255.25532,766
47212.23.0.0/17212.23.0.1 to 212.23.127.254212.23.127.25532,766
48212.23.128.0/17212.23.128.1 to 212.23.255.254212.23.255.25532,766
49212.24.0.0/17212.24.0.1 to 212.24.127.254212.24.127.25532,766
50212.24.128.0/17212.24.128.1 to 212.24.255.254212.24.255.25532,766
51212.25.0.0/17212.25.0.1 to 212.25.127.254212.25.127.25532,766
52212.25.128.0/17212.25.128.1 to 212.25.255.254212.25.255.25532,766
53212.26.0.0/17212.26.0.1 to 212.26.127.254212.26.127.25532,766
54212.26.128.0/17212.26.128.1 to 212.26.255.254212.26.255.25532,766
55212.27.0.0/17212.27.0.1 to 212.27.127.254212.27.127.25532,766
56212.27.128.0/17212.27.128.1 to 212.27.255.254212.27.255.25532,766
57212.28.0.0/17212.28.0.1 to 212.28.127.254212.28.127.25532,766
58212.28.128.0/17212.28.128.1 to 212.28.255.254212.28.255.25532,766
59212.29.0.0/17212.29.0.1 to 212.29.127.254212.29.127.25532,766
60212.29.128.0/17212.29.128.1 to 212.29.255.254212.29.255.25532,766
61212.30.0.0/17212.30.0.1 to 212.30.127.254212.30.127.25532,766
62212.30.128.0/17212.30.128.1 to 212.30.255.254212.30.255.25532,766
63212.31.0.0/17212.31.0.1 to 212.31.127.254212.31.127.25532,766
64212.31.128.0/17212.31.128.1 to 212.31.255.254212.31.255.25532,766
65212.32.0.0/17212.32.0.1 to 212.32.127.254212.32.127.25532,766
66212.32.128.0/17212.32.128.1 to 212.32.255.254212.32.255.25532,766
67212.33.0.0/17212.33.0.1 to 212.33.127.254212.33.127.25532,766
68212.33.128.0/17212.33.128.1 to 212.33.255.254212.33.255.25532,766
69212.34.0.0/17212.34.0.1 to 212.34.127.254212.34.127.25532,766
70212.34.128.0/17212.34.128.1 to 212.34.255.254212.34.255.25532,766
71212.35.0.0/17212.35.0.1 to 212.35.127.254212.35.127.25532,766
72212.35.128.0/17212.35.128.1 to 212.35.255.254212.35.255.25532,766
73212.36.0.0/17212.36.0.1 to 212.36.127.254212.36.127.25532,766
74212.36.128.0/17212.36.128.1 to 212.36.255.254212.36.255.25532,766
75212.37.0.0/17212.37.0.1 to 212.37.127.254212.37.127.25532,766
76212.37.128.0/17212.37.128.1 to 212.37.255.254212.37.255.25532,766
77212.38.0.0/17212.38.0.1 to 212.38.127.254212.38.127.25532,766
78212.38.128.0/17212.38.128.1 to 212.38.255.254212.38.255.25532,766
79212.39.0.0/17212.39.0.1 to 212.39.127.254212.39.127.25532,766
80212.39.128.0/17212.39.128.1 to 212.39.255.254212.39.255.25532,766
81212.40.0.0/17212.40.0.1 to 212.40.127.254212.40.127.25532,766
82212.40.128.0/17212.40.128.1 to 212.40.255.254212.40.255.25532,766
83212.41.0.0/17212.41.0.1 to 212.41.127.254212.41.127.25532,766
84212.41.128.0/17212.41.128.1 to 212.41.255.254212.41.255.25532,766
85212.42.0.0/17212.42.0.1 to 212.42.127.254212.42.127.25532,766
86212.42.128.0/17212.42.128.1 to 212.42.255.254212.42.255.25532,766
87212.43.0.0/17212.43.0.1 to 212.43.127.254212.43.127.25532,766
88212.43.128.0/17212.43.128.1 to 212.43.255.254212.43.255.25532,766
89212.44.0.0/17212.44.0.1 to 212.44.127.254212.44.127.25532,766
90212.44.128.0/17212.44.128.1 to 212.44.255.254212.44.255.25532,766
91212.45.0.0/17212.45.0.1 to 212.45.127.254212.45.127.25532,766
92212.45.128.0/17212.45.128.1 to 212.45.255.254212.45.255.25532,766
93212.46.0.0/17212.46.0.1 to 212.46.127.254212.46.127.25532,766
94212.46.128.0/17212.46.128.1 to 212.46.255.254212.46.255.25532,766
95212.47.0.0/17212.47.0.1 to 212.47.127.254212.47.127.25532,766
96212.47.128.0/17212.47.128.1 to 212.47.255.254212.47.255.25532,766
97212.48.0.0/17212.48.0.1 to 212.48.127.254212.48.127.25532,766
98212.48.128.0/17212.48.128.1 to 212.48.255.254212.48.255.25532,766
99212.49.0.0/17212.49.0.1 to 212.49.127.254212.49.127.25532,766
100212.49.128.0/17212.49.128.1 to 212.49.255.254212.49.255.25532,766
101212.50.0.0/17212.50.0.1 to 212.50.127.254212.50.127.25532,766
102212.50.128.0/17212.50.128.1 to 212.50.255.254212.50.255.25532,766
103212.51.0.0/17212.51.0.1 to 212.51.127.254212.51.127.25532,766
104212.51.128.0/17212.51.128.1 to 212.51.255.254212.51.255.25532,766
105212.52.0.0/17212.52.0.1 to 212.52.127.254212.52.127.25532,766
106212.52.128.0/17212.52.128.1 to 212.52.255.254212.52.255.25532,766
107212.53.0.0/17212.53.0.1 to 212.53.127.254212.53.127.25532,766
108212.53.128.0/17212.53.128.1 to 212.53.255.254212.53.255.25532,766
109212.54.0.0/17212.54.0.1 to 212.54.127.254212.54.127.25532,766
110212.54.128.0/17212.54.128.1 to 212.54.255.254212.54.255.25532,766
111212.55.0.0/17212.55.0.1 to 212.55.127.254212.55.127.25532,766
112212.55.128.0/17212.55.128.1 to 212.55.255.254212.55.255.25532,766
113212.56.0.0/17212.56.0.1 to 212.56.127.254212.56.127.25532,766
114212.56.128.0/17212.56.128.1 to 212.56.255.254212.56.255.25532,766
115212.57.0.0/17212.57.0.1 to 212.57.127.254212.57.127.25532,766
116212.57.128.0/17212.57.128.1 to 212.57.255.254212.57.255.25532,766
117212.58.0.0/17212.58.0.1 to 212.58.127.254212.58.127.25532,766
118212.58.128.0/17212.58.128.1 to 212.58.255.254212.58.255.25532,766
119212.59.0.0/17212.59.0.1 to 212.59.127.254212.59.127.25532,766
120212.59.128.0/17212.59.128.1 to 212.59.255.254212.59.255.25532,766
121212.60.0.0/17212.60.0.1 to 212.60.127.254212.60.127.25532,766
122212.60.128.0/17212.60.128.1 to 212.60.255.254212.60.255.25532,766
123212.61.0.0/17212.61.0.1 to 212.61.127.254212.61.127.25532,766
124212.61.128.0/17212.61.128.1 to 212.61.255.254212.61.255.25532,766
125212.62.0.0/17212.62.0.1 to 212.62.127.254212.62.127.25532,766
126212.62.128.0/17212.62.128.1 to 212.62.255.254212.62.255.25532,766
127212.63.0.0/17212.63.0.1 to 212.63.127.254212.63.127.25532,766
128212.63.128.0/17212.63.128.1 to 212.63.255.254212.63.255.25532,766
129212.64.0.0/17212.64.0.1 to 212.64.127.254212.64.127.25532,766
130212.64.128.0/17212.64.128.1 to 212.64.255.254212.64.255.25532,766
131212.65.0.0/17212.65.0.1 to 212.65.127.254212.65.127.25532,766
132212.65.128.0/17212.65.128.1 to 212.65.255.254212.65.255.25532,766
133212.66.0.0/17212.66.0.1 to 212.66.127.254212.66.127.25532,766
134212.66.128.0/17212.66.128.1 to 212.66.255.254212.66.255.25532,766
135212.67.0.0/17212.67.0.1 to 212.67.127.254212.67.127.25532,766
136212.67.128.0/17212.67.128.1 to 212.67.255.254212.67.255.25532,766
137212.68.0.0/17212.68.0.1 to 212.68.127.254212.68.127.25532,766
138212.68.128.0/17212.68.128.1 to 212.68.255.254212.68.255.25532,766
139212.69.0.0/17212.69.0.1 to 212.69.127.254212.69.127.25532,766
140212.69.128.0/17212.69.128.1 to 212.69.255.254212.69.255.25532,766
141212.70.0.0/17212.70.0.1 to 212.70.127.254212.70.127.25532,766
142212.70.128.0/17212.70.128.1 to 212.70.255.254212.70.255.25532,766
143212.71.0.0/17212.71.0.1 to 212.71.127.254212.71.127.25532,766
144212.71.128.0/17212.71.128.1 to 212.71.255.254212.71.255.25532,766
145212.72.0.0/17212.72.0.1 to 212.72.127.254212.72.127.25532,766
146212.72.128.0/17212.72.128.1 to 212.72.255.254212.72.255.25532,766
147212.73.0.0/17212.73.0.1 to 212.73.127.254212.73.127.25532,766
148212.73.128.0/17212.73.128.1 to 212.73.255.254212.73.255.25532,766
149212.74.0.0/17212.74.0.1 to 212.74.127.254212.74.127.25532,766
150212.74.128.0/17212.74.128.1 to 212.74.255.254212.74.255.25532,766
151212.75.0.0/17212.75.0.1 to 212.75.127.254212.75.127.25532,766
152212.75.128.0/17212.75.128.1 to 212.75.255.254212.75.255.25532,766
153212.76.0.0/17212.76.0.1 to 212.76.127.254212.76.127.25532,766
154212.76.128.0/17212.76.128.1 to 212.76.255.254212.76.255.25532,766
155212.77.0.0/17212.77.0.1 to 212.77.127.254212.77.127.25532,766
156212.77.128.0/17212.77.128.1 to 212.77.255.254212.77.255.25532,766
157212.78.0.0/17212.78.0.1 to 212.78.127.254212.78.127.25532,766
158212.78.128.0/17212.78.128.1 to 212.78.255.254212.78.255.25532,766
159212.79.0.0/17212.79.0.1 to 212.79.127.254212.79.127.25532,766
160212.79.128.0/17212.79.128.1 to 212.79.255.254212.79.255.25532,766
161212.80.0.0/17212.80.0.1 to 212.80.127.254212.80.127.25532,766
162212.80.128.0/17212.80.128.1 to 212.80.255.254212.80.255.25532,766
163212.81.0.0/17212.81.0.1 to 212.81.127.254212.81.127.25532,766
164212.81.128.0/17212.81.128.1 to 212.81.255.254212.81.255.25532,766
165212.82.0.0/17212.82.0.1 to 212.82.127.254212.82.127.25532,766
166212.82.128.0/17212.82.128.1 to 212.82.255.254212.82.255.25532,766
167212.83.0.0/17212.83.0.1 to 212.83.127.254212.83.127.25532,766
168212.83.128.0/17212.83.128.1 to 212.83.255.254212.83.255.25532,766
169212.84.0.0/17212.84.0.1 to 212.84.127.254212.84.127.25532,766
170212.84.128.0/17212.84.128.1 to 212.84.255.254212.84.255.25532,766
171212.85.0.0/17212.85.0.1 to 212.85.127.254212.85.127.25532,766
172212.85.128.0/17212.85.128.1 to 212.85.255.254212.85.255.25532,766
173212.86.0.0/17212.86.0.1 to 212.86.127.254212.86.127.25532,766
174212.86.128.0/17212.86.128.1 to 212.86.255.254212.86.255.25532,766
175212.87.0.0/17212.87.0.1 to 212.87.127.254212.87.127.25532,766
176212.87.128.0/17212.87.128.1 to 212.87.255.254212.87.255.25532,766
177212.88.0.0/17212.88.0.1 to 212.88.127.254212.88.127.25532,766
178212.88.128.0/17212.88.128.1 to 212.88.255.254212.88.255.25532,766
179212.89.0.0/17212.89.0.1 to 212.89.127.254212.89.127.25532,766
180212.89.128.0/17212.89.128.1 to 212.89.255.254212.89.255.25532,766
181212.90.0.0/17212.90.0.1 to 212.90.127.254212.90.127.25532,766
182212.90.128.0/17212.90.128.1 to 212.90.255.254212.90.255.25532,766
183212.91.0.0/17212.91.0.1 to 212.91.127.254212.91.127.25532,766
184212.91.128.0/17212.91.128.1 to 212.91.255.254212.91.255.25532,766
185212.92.0.0/17212.92.0.1 to 212.92.127.254212.92.127.25532,766
186212.92.128.0/17212.92.128.1 to 212.92.255.254212.92.255.25532,766
187212.93.0.0/17212.93.0.1 to 212.93.127.254212.93.127.25532,766
188212.93.128.0/17212.93.128.1 to 212.93.255.254212.93.255.25532,766
189212.94.0.0/17212.94.0.1 to 212.94.127.254212.94.127.25532,766
190212.94.128.0/17212.94.128.1 to 212.94.255.254212.94.255.25532,766
191212.95.0.0/17212.95.0.1 to 212.95.127.254212.95.127.25532,766
192212.95.128.0/17212.95.128.1 to 212.95.255.254212.95.255.25532,766
193212.96.0.0/17212.96.0.1 to 212.96.127.254212.96.127.25532,766
194212.96.128.0/17212.96.128.1 to 212.96.255.254212.96.255.25532,766
195212.97.0.0/17212.97.0.1 to 212.97.127.254212.97.127.25532,766
196212.97.128.0/17212.97.128.1 to 212.97.255.254212.97.255.25532,766
197212.98.0.0/17212.98.0.1 to 212.98.127.254212.98.127.25532,766
198212.98.128.0/17212.98.128.1 to 212.98.255.254212.98.255.25532,766
199212.99.0.0/17212.99.0.1 to 212.99.127.254212.99.127.25532,766
200212.99.128.0/17212.99.128.1 to 212.99.255.254212.99.255.25532,766
201212.100.0.0/17212.100.0.1 to 212.100.127.254212.100.127.25532,766
202212.100.128.0/17212.100.128.1 to 212.100.255.254212.100.255.25532,766
203212.101.0.0/17212.101.0.1 to 212.101.127.254212.101.127.25532,766
204212.101.128.0/17212.101.128.1 to 212.101.255.254212.101.255.25532,766
205212.102.0.0/17212.102.0.1 to 212.102.127.254212.102.127.25532,766
206212.102.128.0/17212.102.128.1 to 212.102.255.254212.102.255.25532,766
207212.103.0.0/17212.103.0.1 to 212.103.127.254212.103.127.25532,766
208212.103.128.0/17212.103.128.1 to 212.103.255.254212.103.255.25532,766
209212.104.0.0/17212.104.0.1 to 212.104.127.254212.104.127.25532,766
210212.104.128.0/17212.104.128.1 to 212.104.255.254212.104.255.25532,766
211212.105.0.0/17212.105.0.1 to 212.105.127.254212.105.127.25532,766
212212.105.128.0/17212.105.128.1 to 212.105.255.254212.105.255.25532,766
213212.106.0.0/17212.106.0.1 to 212.106.127.254212.106.127.25532,766
214212.106.128.0/17212.106.128.1 to 212.106.255.254212.106.255.25532,766
215212.107.0.0/17212.107.0.1 to 212.107.127.254212.107.127.25532,766
216212.107.128.0/17212.107.128.1 to 212.107.255.254212.107.255.25532,766
217212.108.0.0/17212.108.0.1 to 212.108.127.254212.108.127.25532,766
218212.108.128.0/17212.108.128.1 to 212.108.255.254212.108.255.25532,766
219212.109.0.0/17212.109.0.1 to 212.109.127.254212.109.127.25532,766
220212.109.128.0/17212.109.128.1 to 212.109.255.254212.109.255.25532,766
221212.110.0.0/17212.110.0.1 to 212.110.127.254212.110.127.25532,766
222212.110.128.0/17212.110.128.1 to 212.110.255.254212.110.255.25532,766
223212.111.0.0/17212.111.0.1 to 212.111.127.254212.111.127.25532,766
224212.111.128.0/17212.111.128.1 to 212.111.255.254212.111.255.25532,766
225212.112.0.0/17212.112.0.1 to 212.112.127.254212.112.127.25532,766
226212.112.128.0/17212.112.128.1 to 212.112.255.254212.112.255.25532,766
227212.113.0.0/17212.113.0.1 to 212.113.127.254212.113.127.25532,766
228212.113.128.0/17212.113.128.1 to 212.113.255.254212.113.255.25532,766
229212.114.0.0/17212.114.0.1 to 212.114.127.254212.114.127.25532,766
230212.114.128.0/17212.114.128.1 to 212.114.255.254212.114.255.25532,766
231212.115.0.0/17212.115.0.1 to 212.115.127.254212.115.127.25532,766
232212.115.128.0/17212.115.128.1 to 212.115.255.254212.115.255.25532,766
233212.116.0.0/17212.116.0.1 to 212.116.127.254212.116.127.25532,766
234212.116.128.0/17212.116.128.1 to 212.116.255.254212.116.255.25532,766
235212.117.0.0/17212.117.0.1 to 212.117.127.254212.117.127.25532,766
236212.117.128.0/17212.117.128.1 to 212.117.255.254212.117.255.25532,766
237212.118.0.0/17212.118.0.1 to 212.118.127.254212.118.127.25532,766
238212.118.128.0/17212.118.128.1 to 212.118.255.254212.118.255.25532,766
239212.119.0.0/17212.119.0.1 to 212.119.127.254212.119.127.25532,766
240212.119.128.0/17212.119.128.1 to 212.119.255.254212.119.255.25532,766
241212.120.0.0/17212.120.0.1 to 212.120.127.254212.120.127.25532,766
242212.120.128.0/17212.120.128.1 to 212.120.255.254212.120.255.25532,766
243212.121.0.0/17212.121.0.1 to 212.121.127.254212.121.127.25532,766
244212.121.128.0/17212.121.128.1 to 212.121.255.254212.121.255.25532,766
245212.122.0.0/17212.122.0.1 to 212.122.127.254212.122.127.25532,766
246212.122.128.0/17212.122.128.1 to 212.122.255.254212.122.255.25532,766
247212.123.0.0/17212.123.0.1 to 212.123.127.254212.123.127.25532,766
248212.123.128.0/17212.123.128.1 to 212.123.255.254212.123.255.25532,766
249212.124.0.0/17212.124.0.1 to 212.124.127.254212.124.127.25532,766
250212.124.128.0/17212.124.128.1 to 212.124.255.254212.124.255.25532,766
251212.125.0.0/17212.125.0.1 to 212.125.127.254212.125.127.25532,766
252212.125.128.0/17212.125.128.1 to 212.125.255.254212.125.255.25532,766
253212.126.0.0/17212.126.0.1 to 212.126.127.254212.126.127.25532,766
254212.126.128.0/17212.126.128.1 to 212.126.255.254212.126.255.25532,766
255212.127.0.0/17212.127.0.1 to 212.127.127.254212.127.127.25532,766
256212.127.128.0/17212.127.128.1 to 212.127.255.254212.127.255.25532,766

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.