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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.

Network167.0.0.0/9
Usable hosts8,388,606
Subnet mask255.128.0.0
Addresses8,388,608
Network address
167.0.0.0
Broadcast address
167.127.255.255
First usable
167.0.0.1
Last usable
167.127.255.254
Usable hosts
8,388,606 (8,388,608 less the network and broadcast addresses)
Subnet mask
255.128.0.0
Wildcard mask
0.127.255.255 (Cisco ACLs, OSPF)
Prefix length
/9
Type
Public public
Old class
B (default /16)
As numbers
Hex A7000000 · Integer 2801795072 to 2810183679
Reverse DNS zones
0.167.in-addr.arpa
1.167.in-addr.arpa
2.167.in-addr.arpa
3.167.in-addr.arpa
4.167.in-addr.arpa
5.167.in-addr.arpa
6.167.in-addr.arpa
7.167.in-addr.arpa
8.167.in-addr.arpa
9.167.in-addr.arpa
10.167.in-addr.arpa
11.167.in-addr.arpa
12.167.in-addr.arpa
13.167.in-addr.arpa
14.167.in-addr.arpa
15.167.in-addr.arpa
and 112 more
/9 is not on a 8-bit boundary, so it takes 128 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10100111.00000000.00000000.00000000167.0.0.0
Subnet mask11111111.10000000.00000000.00000000255.128.0.0
Network10100111.00000000.00000000.00000000167.0.0.0
Broadcast10100111.01111111.11111111.11111111167.127.255.255
Split into smaller subnets/17
/10 (2)/11 (4)/12 (8)/13 (16)/14 (32)/15 (64)/16 (128)/17 (256)/18 (512)/19 (1,024)/20 (2,048)/21 (4,096)

167.0.0.0/9 makes 256 subnets of /17.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1167.0.0.0/17167.0.0.1 to 167.0.127.254167.0.127.25532,766
2167.0.128.0/17167.0.128.1 to 167.0.255.254167.0.255.25532,766
3167.1.0.0/17167.1.0.1 to 167.1.127.254167.1.127.25532,766
4167.1.128.0/17167.1.128.1 to 167.1.255.254167.1.255.25532,766
5167.2.0.0/17167.2.0.1 to 167.2.127.254167.2.127.25532,766
6167.2.128.0/17167.2.128.1 to 167.2.255.254167.2.255.25532,766
7167.3.0.0/17167.3.0.1 to 167.3.127.254167.3.127.25532,766
8167.3.128.0/17167.3.128.1 to 167.3.255.254167.3.255.25532,766
9167.4.0.0/17167.4.0.1 to 167.4.127.254167.4.127.25532,766
10167.4.128.0/17167.4.128.1 to 167.4.255.254167.4.255.25532,766
11167.5.0.0/17167.5.0.1 to 167.5.127.254167.5.127.25532,766
12167.5.128.0/17167.5.128.1 to 167.5.255.254167.5.255.25532,766
13167.6.0.0/17167.6.0.1 to 167.6.127.254167.6.127.25532,766
14167.6.128.0/17167.6.128.1 to 167.6.255.254167.6.255.25532,766
15167.7.0.0/17167.7.0.1 to 167.7.127.254167.7.127.25532,766
16167.7.128.0/17167.7.128.1 to 167.7.255.254167.7.255.25532,766
17167.8.0.0/17167.8.0.1 to 167.8.127.254167.8.127.25532,766
18167.8.128.0/17167.8.128.1 to 167.8.255.254167.8.255.25532,766
19167.9.0.0/17167.9.0.1 to 167.9.127.254167.9.127.25532,766
20167.9.128.0/17167.9.128.1 to 167.9.255.254167.9.255.25532,766
21167.10.0.0/17167.10.0.1 to 167.10.127.254167.10.127.25532,766
22167.10.128.0/17167.10.128.1 to 167.10.255.254167.10.255.25532,766
23167.11.0.0/17167.11.0.1 to 167.11.127.254167.11.127.25532,766
24167.11.128.0/17167.11.128.1 to 167.11.255.254167.11.255.25532,766
25167.12.0.0/17167.12.0.1 to 167.12.127.254167.12.127.25532,766
26167.12.128.0/17167.12.128.1 to 167.12.255.254167.12.255.25532,766
27167.13.0.0/17167.13.0.1 to 167.13.127.254167.13.127.25532,766
28167.13.128.0/17167.13.128.1 to 167.13.255.254167.13.255.25532,766
29167.14.0.0/17167.14.0.1 to 167.14.127.254167.14.127.25532,766
30167.14.128.0/17167.14.128.1 to 167.14.255.254167.14.255.25532,766
31167.15.0.0/17167.15.0.1 to 167.15.127.254167.15.127.25532,766
32167.15.128.0/17167.15.128.1 to 167.15.255.254167.15.255.25532,766
33167.16.0.0/17167.16.0.1 to 167.16.127.254167.16.127.25532,766
34167.16.128.0/17167.16.128.1 to 167.16.255.254167.16.255.25532,766
35167.17.0.0/17167.17.0.1 to 167.17.127.254167.17.127.25532,766
36167.17.128.0/17167.17.128.1 to 167.17.255.254167.17.255.25532,766
37167.18.0.0/17167.18.0.1 to 167.18.127.254167.18.127.25532,766
38167.18.128.0/17167.18.128.1 to 167.18.255.254167.18.255.25532,766
39167.19.0.0/17167.19.0.1 to 167.19.127.254167.19.127.25532,766
40167.19.128.0/17167.19.128.1 to 167.19.255.254167.19.255.25532,766
41167.20.0.0/17167.20.0.1 to 167.20.127.254167.20.127.25532,766
42167.20.128.0/17167.20.128.1 to 167.20.255.254167.20.255.25532,766
43167.21.0.0/17167.21.0.1 to 167.21.127.254167.21.127.25532,766
44167.21.128.0/17167.21.128.1 to 167.21.255.254167.21.255.25532,766
45167.22.0.0/17167.22.0.1 to 167.22.127.254167.22.127.25532,766
46167.22.128.0/17167.22.128.1 to 167.22.255.254167.22.255.25532,766
47167.23.0.0/17167.23.0.1 to 167.23.127.254167.23.127.25532,766
48167.23.128.0/17167.23.128.1 to 167.23.255.254167.23.255.25532,766
49167.24.0.0/17167.24.0.1 to 167.24.127.254167.24.127.25532,766
50167.24.128.0/17167.24.128.1 to 167.24.255.254167.24.255.25532,766
51167.25.0.0/17167.25.0.1 to 167.25.127.254167.25.127.25532,766
52167.25.128.0/17167.25.128.1 to 167.25.255.254167.25.255.25532,766
53167.26.0.0/17167.26.0.1 to 167.26.127.254167.26.127.25532,766
54167.26.128.0/17167.26.128.1 to 167.26.255.254167.26.255.25532,766
55167.27.0.0/17167.27.0.1 to 167.27.127.254167.27.127.25532,766
56167.27.128.0/17167.27.128.1 to 167.27.255.254167.27.255.25532,766
57167.28.0.0/17167.28.0.1 to 167.28.127.254167.28.127.25532,766
58167.28.128.0/17167.28.128.1 to 167.28.255.254167.28.255.25532,766
59167.29.0.0/17167.29.0.1 to 167.29.127.254167.29.127.25532,766
60167.29.128.0/17167.29.128.1 to 167.29.255.254167.29.255.25532,766
61167.30.0.0/17167.30.0.1 to 167.30.127.254167.30.127.25532,766
62167.30.128.0/17167.30.128.1 to 167.30.255.254167.30.255.25532,766
63167.31.0.0/17167.31.0.1 to 167.31.127.254167.31.127.25532,766
64167.31.128.0/17167.31.128.1 to 167.31.255.254167.31.255.25532,766
65167.32.0.0/17167.32.0.1 to 167.32.127.254167.32.127.25532,766
66167.32.128.0/17167.32.128.1 to 167.32.255.254167.32.255.25532,766
67167.33.0.0/17167.33.0.1 to 167.33.127.254167.33.127.25532,766
68167.33.128.0/17167.33.128.1 to 167.33.255.254167.33.255.25532,766
69167.34.0.0/17167.34.0.1 to 167.34.127.254167.34.127.25532,766
70167.34.128.0/17167.34.128.1 to 167.34.255.254167.34.255.25532,766
71167.35.0.0/17167.35.0.1 to 167.35.127.254167.35.127.25532,766
72167.35.128.0/17167.35.128.1 to 167.35.255.254167.35.255.25532,766
73167.36.0.0/17167.36.0.1 to 167.36.127.254167.36.127.25532,766
74167.36.128.0/17167.36.128.1 to 167.36.255.254167.36.255.25532,766
75167.37.0.0/17167.37.0.1 to 167.37.127.254167.37.127.25532,766
76167.37.128.0/17167.37.128.1 to 167.37.255.254167.37.255.25532,766
77167.38.0.0/17167.38.0.1 to 167.38.127.254167.38.127.25532,766
78167.38.128.0/17167.38.128.1 to 167.38.255.254167.38.255.25532,766
79167.39.0.0/17167.39.0.1 to 167.39.127.254167.39.127.25532,766
80167.39.128.0/17167.39.128.1 to 167.39.255.254167.39.255.25532,766
81167.40.0.0/17167.40.0.1 to 167.40.127.254167.40.127.25532,766
82167.40.128.0/17167.40.128.1 to 167.40.255.254167.40.255.25532,766
83167.41.0.0/17167.41.0.1 to 167.41.127.254167.41.127.25532,766
84167.41.128.0/17167.41.128.1 to 167.41.255.254167.41.255.25532,766
85167.42.0.0/17167.42.0.1 to 167.42.127.254167.42.127.25532,766
86167.42.128.0/17167.42.128.1 to 167.42.255.254167.42.255.25532,766
87167.43.0.0/17167.43.0.1 to 167.43.127.254167.43.127.25532,766
88167.43.128.0/17167.43.128.1 to 167.43.255.254167.43.255.25532,766
89167.44.0.0/17167.44.0.1 to 167.44.127.254167.44.127.25532,766
90167.44.128.0/17167.44.128.1 to 167.44.255.254167.44.255.25532,766
91167.45.0.0/17167.45.0.1 to 167.45.127.254167.45.127.25532,766
92167.45.128.0/17167.45.128.1 to 167.45.255.254167.45.255.25532,766
93167.46.0.0/17167.46.0.1 to 167.46.127.254167.46.127.25532,766
94167.46.128.0/17167.46.128.1 to 167.46.255.254167.46.255.25532,766
95167.47.0.0/17167.47.0.1 to 167.47.127.254167.47.127.25532,766
96167.47.128.0/17167.47.128.1 to 167.47.255.254167.47.255.25532,766
97167.48.0.0/17167.48.0.1 to 167.48.127.254167.48.127.25532,766
98167.48.128.0/17167.48.128.1 to 167.48.255.254167.48.255.25532,766
99167.49.0.0/17167.49.0.1 to 167.49.127.254167.49.127.25532,766
100167.49.128.0/17167.49.128.1 to 167.49.255.254167.49.255.25532,766
101167.50.0.0/17167.50.0.1 to 167.50.127.254167.50.127.25532,766
102167.50.128.0/17167.50.128.1 to 167.50.255.254167.50.255.25532,766
103167.51.0.0/17167.51.0.1 to 167.51.127.254167.51.127.25532,766
104167.51.128.0/17167.51.128.1 to 167.51.255.254167.51.255.25532,766
105167.52.0.0/17167.52.0.1 to 167.52.127.254167.52.127.25532,766
106167.52.128.0/17167.52.128.1 to 167.52.255.254167.52.255.25532,766
107167.53.0.0/17167.53.0.1 to 167.53.127.254167.53.127.25532,766
108167.53.128.0/17167.53.128.1 to 167.53.255.254167.53.255.25532,766
109167.54.0.0/17167.54.0.1 to 167.54.127.254167.54.127.25532,766
110167.54.128.0/17167.54.128.1 to 167.54.255.254167.54.255.25532,766
111167.55.0.0/17167.55.0.1 to 167.55.127.254167.55.127.25532,766
112167.55.128.0/17167.55.128.1 to 167.55.255.254167.55.255.25532,766
113167.56.0.0/17167.56.0.1 to 167.56.127.254167.56.127.25532,766
114167.56.128.0/17167.56.128.1 to 167.56.255.254167.56.255.25532,766
115167.57.0.0/17167.57.0.1 to 167.57.127.254167.57.127.25532,766
116167.57.128.0/17167.57.128.1 to 167.57.255.254167.57.255.25532,766
117167.58.0.0/17167.58.0.1 to 167.58.127.254167.58.127.25532,766
118167.58.128.0/17167.58.128.1 to 167.58.255.254167.58.255.25532,766
119167.59.0.0/17167.59.0.1 to 167.59.127.254167.59.127.25532,766
120167.59.128.0/17167.59.128.1 to 167.59.255.254167.59.255.25532,766
121167.60.0.0/17167.60.0.1 to 167.60.127.254167.60.127.25532,766
122167.60.128.0/17167.60.128.1 to 167.60.255.254167.60.255.25532,766
123167.61.0.0/17167.61.0.1 to 167.61.127.254167.61.127.25532,766
124167.61.128.0/17167.61.128.1 to 167.61.255.254167.61.255.25532,766
125167.62.0.0/17167.62.0.1 to 167.62.127.254167.62.127.25532,766
126167.62.128.0/17167.62.128.1 to 167.62.255.254167.62.255.25532,766
127167.63.0.0/17167.63.0.1 to 167.63.127.254167.63.127.25532,766
128167.63.128.0/17167.63.128.1 to 167.63.255.254167.63.255.25532,766
129167.64.0.0/17167.64.0.1 to 167.64.127.254167.64.127.25532,766
130167.64.128.0/17167.64.128.1 to 167.64.255.254167.64.255.25532,766
131167.65.0.0/17167.65.0.1 to 167.65.127.254167.65.127.25532,766
132167.65.128.0/17167.65.128.1 to 167.65.255.254167.65.255.25532,766
133167.66.0.0/17167.66.0.1 to 167.66.127.254167.66.127.25532,766
134167.66.128.0/17167.66.128.1 to 167.66.255.254167.66.255.25532,766
135167.67.0.0/17167.67.0.1 to 167.67.127.254167.67.127.25532,766
136167.67.128.0/17167.67.128.1 to 167.67.255.254167.67.255.25532,766
137167.68.0.0/17167.68.0.1 to 167.68.127.254167.68.127.25532,766
138167.68.128.0/17167.68.128.1 to 167.68.255.254167.68.255.25532,766
139167.69.0.0/17167.69.0.1 to 167.69.127.254167.69.127.25532,766
140167.69.128.0/17167.69.128.1 to 167.69.255.254167.69.255.25532,766
141167.70.0.0/17167.70.0.1 to 167.70.127.254167.70.127.25532,766
142167.70.128.0/17167.70.128.1 to 167.70.255.254167.70.255.25532,766
143167.71.0.0/17167.71.0.1 to 167.71.127.254167.71.127.25532,766
144167.71.128.0/17167.71.128.1 to 167.71.255.254167.71.255.25532,766
145167.72.0.0/17167.72.0.1 to 167.72.127.254167.72.127.25532,766
146167.72.128.0/17167.72.128.1 to 167.72.255.254167.72.255.25532,766
147167.73.0.0/17167.73.0.1 to 167.73.127.254167.73.127.25532,766
148167.73.128.0/17167.73.128.1 to 167.73.255.254167.73.255.25532,766
149167.74.0.0/17167.74.0.1 to 167.74.127.254167.74.127.25532,766
150167.74.128.0/17167.74.128.1 to 167.74.255.254167.74.255.25532,766
151167.75.0.0/17167.75.0.1 to 167.75.127.254167.75.127.25532,766
152167.75.128.0/17167.75.128.1 to 167.75.255.254167.75.255.25532,766
153167.76.0.0/17167.76.0.1 to 167.76.127.254167.76.127.25532,766
154167.76.128.0/17167.76.128.1 to 167.76.255.254167.76.255.25532,766
155167.77.0.0/17167.77.0.1 to 167.77.127.254167.77.127.25532,766
156167.77.128.0/17167.77.128.1 to 167.77.255.254167.77.255.25532,766
157167.78.0.0/17167.78.0.1 to 167.78.127.254167.78.127.25532,766
158167.78.128.0/17167.78.128.1 to 167.78.255.254167.78.255.25532,766
159167.79.0.0/17167.79.0.1 to 167.79.127.254167.79.127.25532,766
160167.79.128.0/17167.79.128.1 to 167.79.255.254167.79.255.25532,766
161167.80.0.0/17167.80.0.1 to 167.80.127.254167.80.127.25532,766
162167.80.128.0/17167.80.128.1 to 167.80.255.254167.80.255.25532,766
163167.81.0.0/17167.81.0.1 to 167.81.127.254167.81.127.25532,766
164167.81.128.0/17167.81.128.1 to 167.81.255.254167.81.255.25532,766
165167.82.0.0/17167.82.0.1 to 167.82.127.254167.82.127.25532,766
166167.82.128.0/17167.82.128.1 to 167.82.255.254167.82.255.25532,766
167167.83.0.0/17167.83.0.1 to 167.83.127.254167.83.127.25532,766
168167.83.128.0/17167.83.128.1 to 167.83.255.254167.83.255.25532,766
169167.84.0.0/17167.84.0.1 to 167.84.127.254167.84.127.25532,766
170167.84.128.0/17167.84.128.1 to 167.84.255.254167.84.255.25532,766
171167.85.0.0/17167.85.0.1 to 167.85.127.254167.85.127.25532,766
172167.85.128.0/17167.85.128.1 to 167.85.255.254167.85.255.25532,766
173167.86.0.0/17167.86.0.1 to 167.86.127.254167.86.127.25532,766
174167.86.128.0/17167.86.128.1 to 167.86.255.254167.86.255.25532,766
175167.87.0.0/17167.87.0.1 to 167.87.127.254167.87.127.25532,766
176167.87.128.0/17167.87.128.1 to 167.87.255.254167.87.255.25532,766
177167.88.0.0/17167.88.0.1 to 167.88.127.254167.88.127.25532,766
178167.88.128.0/17167.88.128.1 to 167.88.255.254167.88.255.25532,766
179167.89.0.0/17167.89.0.1 to 167.89.127.254167.89.127.25532,766
180167.89.128.0/17167.89.128.1 to 167.89.255.254167.89.255.25532,766
181167.90.0.0/17167.90.0.1 to 167.90.127.254167.90.127.25532,766
182167.90.128.0/17167.90.128.1 to 167.90.255.254167.90.255.25532,766
183167.91.0.0/17167.91.0.1 to 167.91.127.254167.91.127.25532,766
184167.91.128.0/17167.91.128.1 to 167.91.255.254167.91.255.25532,766
185167.92.0.0/17167.92.0.1 to 167.92.127.254167.92.127.25532,766
186167.92.128.0/17167.92.128.1 to 167.92.255.254167.92.255.25532,766
187167.93.0.0/17167.93.0.1 to 167.93.127.254167.93.127.25532,766
188167.93.128.0/17167.93.128.1 to 167.93.255.254167.93.255.25532,766
189167.94.0.0/17167.94.0.1 to 167.94.127.254167.94.127.25532,766
190167.94.128.0/17167.94.128.1 to 167.94.255.254167.94.255.25532,766
191167.95.0.0/17167.95.0.1 to 167.95.127.254167.95.127.25532,766
192167.95.128.0/17167.95.128.1 to 167.95.255.254167.95.255.25532,766
193167.96.0.0/17167.96.0.1 to 167.96.127.254167.96.127.25532,766
194167.96.128.0/17167.96.128.1 to 167.96.255.254167.96.255.25532,766
195167.97.0.0/17167.97.0.1 to 167.97.127.254167.97.127.25532,766
196167.97.128.0/17167.97.128.1 to 167.97.255.254167.97.255.25532,766
197167.98.0.0/17167.98.0.1 to 167.98.127.254167.98.127.25532,766
198167.98.128.0/17167.98.128.1 to 167.98.255.254167.98.255.25532,766
199167.99.0.0/17167.99.0.1 to 167.99.127.254167.99.127.25532,766
200167.99.128.0/17167.99.128.1 to 167.99.255.254167.99.255.25532,766
201167.100.0.0/17167.100.0.1 to 167.100.127.254167.100.127.25532,766
202167.100.128.0/17167.100.128.1 to 167.100.255.254167.100.255.25532,766
203167.101.0.0/17167.101.0.1 to 167.101.127.254167.101.127.25532,766
204167.101.128.0/17167.101.128.1 to 167.101.255.254167.101.255.25532,766
205167.102.0.0/17167.102.0.1 to 167.102.127.254167.102.127.25532,766
206167.102.128.0/17167.102.128.1 to 167.102.255.254167.102.255.25532,766
207167.103.0.0/17167.103.0.1 to 167.103.127.254167.103.127.25532,766
208167.103.128.0/17167.103.128.1 to 167.103.255.254167.103.255.25532,766
209167.104.0.0/17167.104.0.1 to 167.104.127.254167.104.127.25532,766
210167.104.128.0/17167.104.128.1 to 167.104.255.254167.104.255.25532,766
211167.105.0.0/17167.105.0.1 to 167.105.127.254167.105.127.25532,766
212167.105.128.0/17167.105.128.1 to 167.105.255.254167.105.255.25532,766
213167.106.0.0/17167.106.0.1 to 167.106.127.254167.106.127.25532,766
214167.106.128.0/17167.106.128.1 to 167.106.255.254167.106.255.25532,766
215167.107.0.0/17167.107.0.1 to 167.107.127.254167.107.127.25532,766
216167.107.128.0/17167.107.128.1 to 167.107.255.254167.107.255.25532,766
217167.108.0.0/17167.108.0.1 to 167.108.127.254167.108.127.25532,766
218167.108.128.0/17167.108.128.1 to 167.108.255.254167.108.255.25532,766
219167.109.0.0/17167.109.0.1 to 167.109.127.254167.109.127.25532,766
220167.109.128.0/17167.109.128.1 to 167.109.255.254167.109.255.25532,766
221167.110.0.0/17167.110.0.1 to 167.110.127.254167.110.127.25532,766
222167.110.128.0/17167.110.128.1 to 167.110.255.254167.110.255.25532,766
223167.111.0.0/17167.111.0.1 to 167.111.127.254167.111.127.25532,766
224167.111.128.0/17167.111.128.1 to 167.111.255.254167.111.255.25532,766
225167.112.0.0/17167.112.0.1 to 167.112.127.254167.112.127.25532,766
226167.112.128.0/17167.112.128.1 to 167.112.255.254167.112.255.25532,766
227167.113.0.0/17167.113.0.1 to 167.113.127.254167.113.127.25532,766
228167.113.128.0/17167.113.128.1 to 167.113.255.254167.113.255.25532,766
229167.114.0.0/17167.114.0.1 to 167.114.127.254167.114.127.25532,766
230167.114.128.0/17167.114.128.1 to 167.114.255.254167.114.255.25532,766
231167.115.0.0/17167.115.0.1 to 167.115.127.254167.115.127.25532,766
232167.115.128.0/17167.115.128.1 to 167.115.255.254167.115.255.25532,766
233167.116.0.0/17167.116.0.1 to 167.116.127.254167.116.127.25532,766
234167.116.128.0/17167.116.128.1 to 167.116.255.254167.116.255.25532,766
235167.117.0.0/17167.117.0.1 to 167.117.127.254167.117.127.25532,766
236167.117.128.0/17167.117.128.1 to 167.117.255.254167.117.255.25532,766
237167.118.0.0/17167.118.0.1 to 167.118.127.254167.118.127.25532,766
238167.118.128.0/17167.118.128.1 to 167.118.255.254167.118.255.25532,766
239167.119.0.0/17167.119.0.1 to 167.119.127.254167.119.127.25532,766
240167.119.128.0/17167.119.128.1 to 167.119.255.254167.119.255.25532,766
241167.120.0.0/17167.120.0.1 to 167.120.127.254167.120.127.25532,766
242167.120.128.0/17167.120.128.1 to 167.120.255.254167.120.255.25532,766
243167.121.0.0/17167.121.0.1 to 167.121.127.254167.121.127.25532,766
244167.121.128.0/17167.121.128.1 to 167.121.255.254167.121.255.25532,766
245167.122.0.0/17167.122.0.1 to 167.122.127.254167.122.127.25532,766
246167.122.128.0/17167.122.128.1 to 167.122.255.254167.122.255.25532,766
247167.123.0.0/17167.123.0.1 to 167.123.127.254167.123.127.25532,766
248167.123.128.0/17167.123.128.1 to 167.123.255.254167.123.255.25532,766
249167.124.0.0/17167.124.0.1 to 167.124.127.254167.124.127.25532,766
250167.124.128.0/17167.124.128.1 to 167.124.255.254167.124.255.25532,766
251167.125.0.0/17167.125.0.1 to 167.125.127.254167.125.127.25532,766
252167.125.128.0/17167.125.128.1 to 167.125.255.254167.125.255.25532,766
253167.126.0.0/17167.126.0.1 to 167.126.127.254167.126.127.25532,766
254167.126.128.0/17167.126.128.1 to 167.126.255.254167.126.255.25532,766
255167.127.0.0/17167.127.0.1 to 167.127.127.254167.127.127.25532,766
256167.127.128.0/17167.127.128.1 to 167.127.255.254167.127.255.25532,766

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.