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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.

Network156.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
156.0.0.0
Broadcast address
156.255.255.255
First usable
156.0.0.1
Last usable
156.255.255.254
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
B (default /16)
As numbers
Hex 9C000000 · Integer 2617245696 to 2634022911
Reverse DNS zone
156.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10011100..00000000.00000000.00000000156.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network10011100..00000000.00000000.00000000156.0.0.0
Broadcast10011100..11111111.11111111.11111111156.255.255.255
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)

156.0.0.0/8 makes 512 subnets of /17; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1156.0.0.0/17156.0.0.1 to 156.0.127.254156.0.127.25532,766
2156.0.128.0/17156.0.128.1 to 156.0.255.254156.0.255.25532,766
3156.1.0.0/17156.1.0.1 to 156.1.127.254156.1.127.25532,766
4156.1.128.0/17156.1.128.1 to 156.1.255.254156.1.255.25532,766
5156.2.0.0/17156.2.0.1 to 156.2.127.254156.2.127.25532,766
6156.2.128.0/17156.2.128.1 to 156.2.255.254156.2.255.25532,766
7156.3.0.0/17156.3.0.1 to 156.3.127.254156.3.127.25532,766
8156.3.128.0/17156.3.128.1 to 156.3.255.254156.3.255.25532,766
9156.4.0.0/17156.4.0.1 to 156.4.127.254156.4.127.25532,766
10156.4.128.0/17156.4.128.1 to 156.4.255.254156.4.255.25532,766
11156.5.0.0/17156.5.0.1 to 156.5.127.254156.5.127.25532,766
12156.5.128.0/17156.5.128.1 to 156.5.255.254156.5.255.25532,766
13156.6.0.0/17156.6.0.1 to 156.6.127.254156.6.127.25532,766
14156.6.128.0/17156.6.128.1 to 156.6.255.254156.6.255.25532,766
15156.7.0.0/17156.7.0.1 to 156.7.127.254156.7.127.25532,766
16156.7.128.0/17156.7.128.1 to 156.7.255.254156.7.255.25532,766
17156.8.0.0/17156.8.0.1 to 156.8.127.254156.8.127.25532,766
18156.8.128.0/17156.8.128.1 to 156.8.255.254156.8.255.25532,766
19156.9.0.0/17156.9.0.1 to 156.9.127.254156.9.127.25532,766
20156.9.128.0/17156.9.128.1 to 156.9.255.254156.9.255.25532,766
21156.10.0.0/17156.10.0.1 to 156.10.127.254156.10.127.25532,766
22156.10.128.0/17156.10.128.1 to 156.10.255.254156.10.255.25532,766
23156.11.0.0/17156.11.0.1 to 156.11.127.254156.11.127.25532,766
24156.11.128.0/17156.11.128.1 to 156.11.255.254156.11.255.25532,766
25156.12.0.0/17156.12.0.1 to 156.12.127.254156.12.127.25532,766
26156.12.128.0/17156.12.128.1 to 156.12.255.254156.12.255.25532,766
27156.13.0.0/17156.13.0.1 to 156.13.127.254156.13.127.25532,766
28156.13.128.0/17156.13.128.1 to 156.13.255.254156.13.255.25532,766
29156.14.0.0/17156.14.0.1 to 156.14.127.254156.14.127.25532,766
30156.14.128.0/17156.14.128.1 to 156.14.255.254156.14.255.25532,766
31156.15.0.0/17156.15.0.1 to 156.15.127.254156.15.127.25532,766
32156.15.128.0/17156.15.128.1 to 156.15.255.254156.15.255.25532,766
33156.16.0.0/17156.16.0.1 to 156.16.127.254156.16.127.25532,766
34156.16.128.0/17156.16.128.1 to 156.16.255.254156.16.255.25532,766
35156.17.0.0/17156.17.0.1 to 156.17.127.254156.17.127.25532,766
36156.17.128.0/17156.17.128.1 to 156.17.255.254156.17.255.25532,766
37156.18.0.0/17156.18.0.1 to 156.18.127.254156.18.127.25532,766
38156.18.128.0/17156.18.128.1 to 156.18.255.254156.18.255.25532,766
39156.19.0.0/17156.19.0.1 to 156.19.127.254156.19.127.25532,766
40156.19.128.0/17156.19.128.1 to 156.19.255.254156.19.255.25532,766
41156.20.0.0/17156.20.0.1 to 156.20.127.254156.20.127.25532,766
42156.20.128.0/17156.20.128.1 to 156.20.255.254156.20.255.25532,766
43156.21.0.0/17156.21.0.1 to 156.21.127.254156.21.127.25532,766
44156.21.128.0/17156.21.128.1 to 156.21.255.254156.21.255.25532,766
45156.22.0.0/17156.22.0.1 to 156.22.127.254156.22.127.25532,766
46156.22.128.0/17156.22.128.1 to 156.22.255.254156.22.255.25532,766
47156.23.0.0/17156.23.0.1 to 156.23.127.254156.23.127.25532,766
48156.23.128.0/17156.23.128.1 to 156.23.255.254156.23.255.25532,766
49156.24.0.0/17156.24.0.1 to 156.24.127.254156.24.127.25532,766
50156.24.128.0/17156.24.128.1 to 156.24.255.254156.24.255.25532,766
51156.25.0.0/17156.25.0.1 to 156.25.127.254156.25.127.25532,766
52156.25.128.0/17156.25.128.1 to 156.25.255.254156.25.255.25532,766
53156.26.0.0/17156.26.0.1 to 156.26.127.254156.26.127.25532,766
54156.26.128.0/17156.26.128.1 to 156.26.255.254156.26.255.25532,766
55156.27.0.0/17156.27.0.1 to 156.27.127.254156.27.127.25532,766
56156.27.128.0/17156.27.128.1 to 156.27.255.254156.27.255.25532,766
57156.28.0.0/17156.28.0.1 to 156.28.127.254156.28.127.25532,766
58156.28.128.0/17156.28.128.1 to 156.28.255.254156.28.255.25532,766
59156.29.0.0/17156.29.0.1 to 156.29.127.254156.29.127.25532,766
60156.29.128.0/17156.29.128.1 to 156.29.255.254156.29.255.25532,766
61156.30.0.0/17156.30.0.1 to 156.30.127.254156.30.127.25532,766
62156.30.128.0/17156.30.128.1 to 156.30.255.254156.30.255.25532,766
63156.31.0.0/17156.31.0.1 to 156.31.127.254156.31.127.25532,766
64156.31.128.0/17156.31.128.1 to 156.31.255.254156.31.255.25532,766
65156.32.0.0/17156.32.0.1 to 156.32.127.254156.32.127.25532,766
66156.32.128.0/17156.32.128.1 to 156.32.255.254156.32.255.25532,766
67156.33.0.0/17156.33.0.1 to 156.33.127.254156.33.127.25532,766
68156.33.128.0/17156.33.128.1 to 156.33.255.254156.33.255.25532,766
69156.34.0.0/17156.34.0.1 to 156.34.127.254156.34.127.25532,766
70156.34.128.0/17156.34.128.1 to 156.34.255.254156.34.255.25532,766
71156.35.0.0/17156.35.0.1 to 156.35.127.254156.35.127.25532,766
72156.35.128.0/17156.35.128.1 to 156.35.255.254156.35.255.25532,766
73156.36.0.0/17156.36.0.1 to 156.36.127.254156.36.127.25532,766
74156.36.128.0/17156.36.128.1 to 156.36.255.254156.36.255.25532,766
75156.37.0.0/17156.37.0.1 to 156.37.127.254156.37.127.25532,766
76156.37.128.0/17156.37.128.1 to 156.37.255.254156.37.255.25532,766
77156.38.0.0/17156.38.0.1 to 156.38.127.254156.38.127.25532,766
78156.38.128.0/17156.38.128.1 to 156.38.255.254156.38.255.25532,766
79156.39.0.0/17156.39.0.1 to 156.39.127.254156.39.127.25532,766
80156.39.128.0/17156.39.128.1 to 156.39.255.254156.39.255.25532,766
81156.40.0.0/17156.40.0.1 to 156.40.127.254156.40.127.25532,766
82156.40.128.0/17156.40.128.1 to 156.40.255.254156.40.255.25532,766
83156.41.0.0/17156.41.0.1 to 156.41.127.254156.41.127.25532,766
84156.41.128.0/17156.41.128.1 to 156.41.255.254156.41.255.25532,766
85156.42.0.0/17156.42.0.1 to 156.42.127.254156.42.127.25532,766
86156.42.128.0/17156.42.128.1 to 156.42.255.254156.42.255.25532,766
87156.43.0.0/17156.43.0.1 to 156.43.127.254156.43.127.25532,766
88156.43.128.0/17156.43.128.1 to 156.43.255.254156.43.255.25532,766
89156.44.0.0/17156.44.0.1 to 156.44.127.254156.44.127.25532,766
90156.44.128.0/17156.44.128.1 to 156.44.255.254156.44.255.25532,766
91156.45.0.0/17156.45.0.1 to 156.45.127.254156.45.127.25532,766
92156.45.128.0/17156.45.128.1 to 156.45.255.254156.45.255.25532,766
93156.46.0.0/17156.46.0.1 to 156.46.127.254156.46.127.25532,766
94156.46.128.0/17156.46.128.1 to 156.46.255.254156.46.255.25532,766
95156.47.0.0/17156.47.0.1 to 156.47.127.254156.47.127.25532,766
96156.47.128.0/17156.47.128.1 to 156.47.255.254156.47.255.25532,766
97156.48.0.0/17156.48.0.1 to 156.48.127.254156.48.127.25532,766
98156.48.128.0/17156.48.128.1 to 156.48.255.254156.48.255.25532,766
99156.49.0.0/17156.49.0.1 to 156.49.127.254156.49.127.25532,766
100156.49.128.0/17156.49.128.1 to 156.49.255.254156.49.255.25532,766
101156.50.0.0/17156.50.0.1 to 156.50.127.254156.50.127.25532,766
102156.50.128.0/17156.50.128.1 to 156.50.255.254156.50.255.25532,766
103156.51.0.0/17156.51.0.1 to 156.51.127.254156.51.127.25532,766
104156.51.128.0/17156.51.128.1 to 156.51.255.254156.51.255.25532,766
105156.52.0.0/17156.52.0.1 to 156.52.127.254156.52.127.25532,766
106156.52.128.0/17156.52.128.1 to 156.52.255.254156.52.255.25532,766
107156.53.0.0/17156.53.0.1 to 156.53.127.254156.53.127.25532,766
108156.53.128.0/17156.53.128.1 to 156.53.255.254156.53.255.25532,766
109156.54.0.0/17156.54.0.1 to 156.54.127.254156.54.127.25532,766
110156.54.128.0/17156.54.128.1 to 156.54.255.254156.54.255.25532,766
111156.55.0.0/17156.55.0.1 to 156.55.127.254156.55.127.25532,766
112156.55.128.0/17156.55.128.1 to 156.55.255.254156.55.255.25532,766
113156.56.0.0/17156.56.0.1 to 156.56.127.254156.56.127.25532,766
114156.56.128.0/17156.56.128.1 to 156.56.255.254156.56.255.25532,766
115156.57.0.0/17156.57.0.1 to 156.57.127.254156.57.127.25532,766
116156.57.128.0/17156.57.128.1 to 156.57.255.254156.57.255.25532,766
117156.58.0.0/17156.58.0.1 to 156.58.127.254156.58.127.25532,766
118156.58.128.0/17156.58.128.1 to 156.58.255.254156.58.255.25532,766
119156.59.0.0/17156.59.0.1 to 156.59.127.254156.59.127.25532,766
120156.59.128.0/17156.59.128.1 to 156.59.255.254156.59.255.25532,766
121156.60.0.0/17156.60.0.1 to 156.60.127.254156.60.127.25532,766
122156.60.128.0/17156.60.128.1 to 156.60.255.254156.60.255.25532,766
123156.61.0.0/17156.61.0.1 to 156.61.127.254156.61.127.25532,766
124156.61.128.0/17156.61.128.1 to 156.61.255.254156.61.255.25532,766
125156.62.0.0/17156.62.0.1 to 156.62.127.254156.62.127.25532,766
126156.62.128.0/17156.62.128.1 to 156.62.255.254156.62.255.25532,766
127156.63.0.0/17156.63.0.1 to 156.63.127.254156.63.127.25532,766
128156.63.128.0/17156.63.128.1 to 156.63.255.254156.63.255.25532,766
129156.64.0.0/17156.64.0.1 to 156.64.127.254156.64.127.25532,766
130156.64.128.0/17156.64.128.1 to 156.64.255.254156.64.255.25532,766
131156.65.0.0/17156.65.0.1 to 156.65.127.254156.65.127.25532,766
132156.65.128.0/17156.65.128.1 to 156.65.255.254156.65.255.25532,766
133156.66.0.0/17156.66.0.1 to 156.66.127.254156.66.127.25532,766
134156.66.128.0/17156.66.128.1 to 156.66.255.254156.66.255.25532,766
135156.67.0.0/17156.67.0.1 to 156.67.127.254156.67.127.25532,766
136156.67.128.0/17156.67.128.1 to 156.67.255.254156.67.255.25532,766
137156.68.0.0/17156.68.0.1 to 156.68.127.254156.68.127.25532,766
138156.68.128.0/17156.68.128.1 to 156.68.255.254156.68.255.25532,766
139156.69.0.0/17156.69.0.1 to 156.69.127.254156.69.127.25532,766
140156.69.128.0/17156.69.128.1 to 156.69.255.254156.69.255.25532,766
141156.70.0.0/17156.70.0.1 to 156.70.127.254156.70.127.25532,766
142156.70.128.0/17156.70.128.1 to 156.70.255.254156.70.255.25532,766
143156.71.0.0/17156.71.0.1 to 156.71.127.254156.71.127.25532,766
144156.71.128.0/17156.71.128.1 to 156.71.255.254156.71.255.25532,766
145156.72.0.0/17156.72.0.1 to 156.72.127.254156.72.127.25532,766
146156.72.128.0/17156.72.128.1 to 156.72.255.254156.72.255.25532,766
147156.73.0.0/17156.73.0.1 to 156.73.127.254156.73.127.25532,766
148156.73.128.0/17156.73.128.1 to 156.73.255.254156.73.255.25532,766
149156.74.0.0/17156.74.0.1 to 156.74.127.254156.74.127.25532,766
150156.74.128.0/17156.74.128.1 to 156.74.255.254156.74.255.25532,766
151156.75.0.0/17156.75.0.1 to 156.75.127.254156.75.127.25532,766
152156.75.128.0/17156.75.128.1 to 156.75.255.254156.75.255.25532,766
153156.76.0.0/17156.76.0.1 to 156.76.127.254156.76.127.25532,766
154156.76.128.0/17156.76.128.1 to 156.76.255.254156.76.255.25532,766
155156.77.0.0/17156.77.0.1 to 156.77.127.254156.77.127.25532,766
156156.77.128.0/17156.77.128.1 to 156.77.255.254156.77.255.25532,766
157156.78.0.0/17156.78.0.1 to 156.78.127.254156.78.127.25532,766
158156.78.128.0/17156.78.128.1 to 156.78.255.254156.78.255.25532,766
159156.79.0.0/17156.79.0.1 to 156.79.127.254156.79.127.25532,766
160156.79.128.0/17156.79.128.1 to 156.79.255.254156.79.255.25532,766
161156.80.0.0/17156.80.0.1 to 156.80.127.254156.80.127.25532,766
162156.80.128.0/17156.80.128.1 to 156.80.255.254156.80.255.25532,766
163156.81.0.0/17156.81.0.1 to 156.81.127.254156.81.127.25532,766
164156.81.128.0/17156.81.128.1 to 156.81.255.254156.81.255.25532,766
165156.82.0.0/17156.82.0.1 to 156.82.127.254156.82.127.25532,766
166156.82.128.0/17156.82.128.1 to 156.82.255.254156.82.255.25532,766
167156.83.0.0/17156.83.0.1 to 156.83.127.254156.83.127.25532,766
168156.83.128.0/17156.83.128.1 to 156.83.255.254156.83.255.25532,766
169156.84.0.0/17156.84.0.1 to 156.84.127.254156.84.127.25532,766
170156.84.128.0/17156.84.128.1 to 156.84.255.254156.84.255.25532,766
171156.85.0.0/17156.85.0.1 to 156.85.127.254156.85.127.25532,766
172156.85.128.0/17156.85.128.1 to 156.85.255.254156.85.255.25532,766
173156.86.0.0/17156.86.0.1 to 156.86.127.254156.86.127.25532,766
174156.86.128.0/17156.86.128.1 to 156.86.255.254156.86.255.25532,766
175156.87.0.0/17156.87.0.1 to 156.87.127.254156.87.127.25532,766
176156.87.128.0/17156.87.128.1 to 156.87.255.254156.87.255.25532,766
177156.88.0.0/17156.88.0.1 to 156.88.127.254156.88.127.25532,766
178156.88.128.0/17156.88.128.1 to 156.88.255.254156.88.255.25532,766
179156.89.0.0/17156.89.0.1 to 156.89.127.254156.89.127.25532,766
180156.89.128.0/17156.89.128.1 to 156.89.255.254156.89.255.25532,766
181156.90.0.0/17156.90.0.1 to 156.90.127.254156.90.127.25532,766
182156.90.128.0/17156.90.128.1 to 156.90.255.254156.90.255.25532,766
183156.91.0.0/17156.91.0.1 to 156.91.127.254156.91.127.25532,766
184156.91.128.0/17156.91.128.1 to 156.91.255.254156.91.255.25532,766
185156.92.0.0/17156.92.0.1 to 156.92.127.254156.92.127.25532,766
186156.92.128.0/17156.92.128.1 to 156.92.255.254156.92.255.25532,766
187156.93.0.0/17156.93.0.1 to 156.93.127.254156.93.127.25532,766
188156.93.128.0/17156.93.128.1 to 156.93.255.254156.93.255.25532,766
189156.94.0.0/17156.94.0.1 to 156.94.127.254156.94.127.25532,766
190156.94.128.0/17156.94.128.1 to 156.94.255.254156.94.255.25532,766
191156.95.0.0/17156.95.0.1 to 156.95.127.254156.95.127.25532,766
192156.95.128.0/17156.95.128.1 to 156.95.255.254156.95.255.25532,766
193156.96.0.0/17156.96.0.1 to 156.96.127.254156.96.127.25532,766
194156.96.128.0/17156.96.128.1 to 156.96.255.254156.96.255.25532,766
195156.97.0.0/17156.97.0.1 to 156.97.127.254156.97.127.25532,766
196156.97.128.0/17156.97.128.1 to 156.97.255.254156.97.255.25532,766
197156.98.0.0/17156.98.0.1 to 156.98.127.254156.98.127.25532,766
198156.98.128.0/17156.98.128.1 to 156.98.255.254156.98.255.25532,766
199156.99.0.0/17156.99.0.1 to 156.99.127.254156.99.127.25532,766
200156.99.128.0/17156.99.128.1 to 156.99.255.254156.99.255.25532,766
201156.100.0.0/17156.100.0.1 to 156.100.127.254156.100.127.25532,766
202156.100.128.0/17156.100.128.1 to 156.100.255.254156.100.255.25532,766
203156.101.0.0/17156.101.0.1 to 156.101.127.254156.101.127.25532,766
204156.101.128.0/17156.101.128.1 to 156.101.255.254156.101.255.25532,766
205156.102.0.0/17156.102.0.1 to 156.102.127.254156.102.127.25532,766
206156.102.128.0/17156.102.128.1 to 156.102.255.254156.102.255.25532,766
207156.103.0.0/17156.103.0.1 to 156.103.127.254156.103.127.25532,766
208156.103.128.0/17156.103.128.1 to 156.103.255.254156.103.255.25532,766
209156.104.0.0/17156.104.0.1 to 156.104.127.254156.104.127.25532,766
210156.104.128.0/17156.104.128.1 to 156.104.255.254156.104.255.25532,766
211156.105.0.0/17156.105.0.1 to 156.105.127.254156.105.127.25532,766
212156.105.128.0/17156.105.128.1 to 156.105.255.254156.105.255.25532,766
213156.106.0.0/17156.106.0.1 to 156.106.127.254156.106.127.25532,766
214156.106.128.0/17156.106.128.1 to 156.106.255.254156.106.255.25532,766
215156.107.0.0/17156.107.0.1 to 156.107.127.254156.107.127.25532,766
216156.107.128.0/17156.107.128.1 to 156.107.255.254156.107.255.25532,766
217156.108.0.0/17156.108.0.1 to 156.108.127.254156.108.127.25532,766
218156.108.128.0/17156.108.128.1 to 156.108.255.254156.108.255.25532,766
219156.109.0.0/17156.109.0.1 to 156.109.127.254156.109.127.25532,766
220156.109.128.0/17156.109.128.1 to 156.109.255.254156.109.255.25532,766
221156.110.0.0/17156.110.0.1 to 156.110.127.254156.110.127.25532,766
222156.110.128.0/17156.110.128.1 to 156.110.255.254156.110.255.25532,766
223156.111.0.0/17156.111.0.1 to 156.111.127.254156.111.127.25532,766
224156.111.128.0/17156.111.128.1 to 156.111.255.254156.111.255.25532,766
225156.112.0.0/17156.112.0.1 to 156.112.127.254156.112.127.25532,766
226156.112.128.0/17156.112.128.1 to 156.112.255.254156.112.255.25532,766
227156.113.0.0/17156.113.0.1 to 156.113.127.254156.113.127.25532,766
228156.113.128.0/17156.113.128.1 to 156.113.255.254156.113.255.25532,766
229156.114.0.0/17156.114.0.1 to 156.114.127.254156.114.127.25532,766
230156.114.128.0/17156.114.128.1 to 156.114.255.254156.114.255.25532,766
231156.115.0.0/17156.115.0.1 to 156.115.127.254156.115.127.25532,766
232156.115.128.0/17156.115.128.1 to 156.115.255.254156.115.255.25532,766
233156.116.0.0/17156.116.0.1 to 156.116.127.254156.116.127.25532,766
234156.116.128.0/17156.116.128.1 to 156.116.255.254156.116.255.25532,766
235156.117.0.0/17156.117.0.1 to 156.117.127.254156.117.127.25532,766
236156.117.128.0/17156.117.128.1 to 156.117.255.254156.117.255.25532,766
237156.118.0.0/17156.118.0.1 to 156.118.127.254156.118.127.25532,766
238156.118.128.0/17156.118.128.1 to 156.118.255.254156.118.255.25532,766
239156.119.0.0/17156.119.0.1 to 156.119.127.254156.119.127.25532,766
240156.119.128.0/17156.119.128.1 to 156.119.255.254156.119.255.25532,766
241156.120.0.0/17156.120.0.1 to 156.120.127.254156.120.127.25532,766
242156.120.128.0/17156.120.128.1 to 156.120.255.254156.120.255.25532,766
243156.121.0.0/17156.121.0.1 to 156.121.127.254156.121.127.25532,766
244156.121.128.0/17156.121.128.1 to 156.121.255.254156.121.255.25532,766
245156.122.0.0/17156.122.0.1 to 156.122.127.254156.122.127.25532,766
246156.122.128.0/17156.122.128.1 to 156.122.255.254156.122.255.25532,766
247156.123.0.0/17156.123.0.1 to 156.123.127.254156.123.127.25532,766
248156.123.128.0/17156.123.128.1 to 156.123.255.254156.123.255.25532,766
249156.124.0.0/17156.124.0.1 to 156.124.127.254156.124.127.25532,766
250156.124.128.0/17156.124.128.1 to 156.124.255.254156.124.255.25532,766
251156.125.0.0/17156.125.0.1 to 156.125.127.254156.125.127.25532,766
252156.125.128.0/17156.125.128.1 to 156.125.255.254156.125.255.25532,766
253156.126.0.0/17156.126.0.1 to 156.126.127.254156.126.127.25532,766
254156.126.128.0/17156.126.128.1 to 156.126.255.254156.126.255.25532,766
255156.127.0.0/17156.127.0.1 to 156.127.127.254156.127.127.25532,766
256156.127.128.0/17156.127.128.1 to 156.127.255.254156.127.255.25532,766

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.