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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/18
/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 1,024 subnets of /18; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1156.0.0.0/18156.0.0.1 to 156.0.63.254156.0.63.25516,382
2156.0.64.0/18156.0.64.1 to 156.0.127.254156.0.127.25516,382
3156.0.128.0/18156.0.128.1 to 156.0.191.254156.0.191.25516,382
4156.0.192.0/18156.0.192.1 to 156.0.255.254156.0.255.25516,382
5156.1.0.0/18156.1.0.1 to 156.1.63.254156.1.63.25516,382
6156.1.64.0/18156.1.64.1 to 156.1.127.254156.1.127.25516,382
7156.1.128.0/18156.1.128.1 to 156.1.191.254156.1.191.25516,382
8156.1.192.0/18156.1.192.1 to 156.1.255.254156.1.255.25516,382
9156.2.0.0/18156.2.0.1 to 156.2.63.254156.2.63.25516,382
10156.2.64.0/18156.2.64.1 to 156.2.127.254156.2.127.25516,382
11156.2.128.0/18156.2.128.1 to 156.2.191.254156.2.191.25516,382
12156.2.192.0/18156.2.192.1 to 156.2.255.254156.2.255.25516,382
13156.3.0.0/18156.3.0.1 to 156.3.63.254156.3.63.25516,382
14156.3.64.0/18156.3.64.1 to 156.3.127.254156.3.127.25516,382
15156.3.128.0/18156.3.128.1 to 156.3.191.254156.3.191.25516,382
16156.3.192.0/18156.3.192.1 to 156.3.255.254156.3.255.25516,382
17156.4.0.0/18156.4.0.1 to 156.4.63.254156.4.63.25516,382
18156.4.64.0/18156.4.64.1 to 156.4.127.254156.4.127.25516,382
19156.4.128.0/18156.4.128.1 to 156.4.191.254156.4.191.25516,382
20156.4.192.0/18156.4.192.1 to 156.4.255.254156.4.255.25516,382
21156.5.0.0/18156.5.0.1 to 156.5.63.254156.5.63.25516,382
22156.5.64.0/18156.5.64.1 to 156.5.127.254156.5.127.25516,382
23156.5.128.0/18156.5.128.1 to 156.5.191.254156.5.191.25516,382
24156.5.192.0/18156.5.192.1 to 156.5.255.254156.5.255.25516,382
25156.6.0.0/18156.6.0.1 to 156.6.63.254156.6.63.25516,382
26156.6.64.0/18156.6.64.1 to 156.6.127.254156.6.127.25516,382
27156.6.128.0/18156.6.128.1 to 156.6.191.254156.6.191.25516,382
28156.6.192.0/18156.6.192.1 to 156.6.255.254156.6.255.25516,382
29156.7.0.0/18156.7.0.1 to 156.7.63.254156.7.63.25516,382
30156.7.64.0/18156.7.64.1 to 156.7.127.254156.7.127.25516,382
31156.7.128.0/18156.7.128.1 to 156.7.191.254156.7.191.25516,382
32156.7.192.0/18156.7.192.1 to 156.7.255.254156.7.255.25516,382
33156.8.0.0/18156.8.0.1 to 156.8.63.254156.8.63.25516,382
34156.8.64.0/18156.8.64.1 to 156.8.127.254156.8.127.25516,382
35156.8.128.0/18156.8.128.1 to 156.8.191.254156.8.191.25516,382
36156.8.192.0/18156.8.192.1 to 156.8.255.254156.8.255.25516,382
37156.9.0.0/18156.9.0.1 to 156.9.63.254156.9.63.25516,382
38156.9.64.0/18156.9.64.1 to 156.9.127.254156.9.127.25516,382
39156.9.128.0/18156.9.128.1 to 156.9.191.254156.9.191.25516,382
40156.9.192.0/18156.9.192.1 to 156.9.255.254156.9.255.25516,382
41156.10.0.0/18156.10.0.1 to 156.10.63.254156.10.63.25516,382
42156.10.64.0/18156.10.64.1 to 156.10.127.254156.10.127.25516,382
43156.10.128.0/18156.10.128.1 to 156.10.191.254156.10.191.25516,382
44156.10.192.0/18156.10.192.1 to 156.10.255.254156.10.255.25516,382
45156.11.0.0/18156.11.0.1 to 156.11.63.254156.11.63.25516,382
46156.11.64.0/18156.11.64.1 to 156.11.127.254156.11.127.25516,382
47156.11.128.0/18156.11.128.1 to 156.11.191.254156.11.191.25516,382
48156.11.192.0/18156.11.192.1 to 156.11.255.254156.11.255.25516,382
49156.12.0.0/18156.12.0.1 to 156.12.63.254156.12.63.25516,382
50156.12.64.0/18156.12.64.1 to 156.12.127.254156.12.127.25516,382
51156.12.128.0/18156.12.128.1 to 156.12.191.254156.12.191.25516,382
52156.12.192.0/18156.12.192.1 to 156.12.255.254156.12.255.25516,382
53156.13.0.0/18156.13.0.1 to 156.13.63.254156.13.63.25516,382
54156.13.64.0/18156.13.64.1 to 156.13.127.254156.13.127.25516,382
55156.13.128.0/18156.13.128.1 to 156.13.191.254156.13.191.25516,382
56156.13.192.0/18156.13.192.1 to 156.13.255.254156.13.255.25516,382
57156.14.0.0/18156.14.0.1 to 156.14.63.254156.14.63.25516,382
58156.14.64.0/18156.14.64.1 to 156.14.127.254156.14.127.25516,382
59156.14.128.0/18156.14.128.1 to 156.14.191.254156.14.191.25516,382
60156.14.192.0/18156.14.192.1 to 156.14.255.254156.14.255.25516,382
61156.15.0.0/18156.15.0.1 to 156.15.63.254156.15.63.25516,382
62156.15.64.0/18156.15.64.1 to 156.15.127.254156.15.127.25516,382
63156.15.128.0/18156.15.128.1 to 156.15.191.254156.15.191.25516,382
64156.15.192.0/18156.15.192.1 to 156.15.255.254156.15.255.25516,382
65156.16.0.0/18156.16.0.1 to 156.16.63.254156.16.63.25516,382
66156.16.64.0/18156.16.64.1 to 156.16.127.254156.16.127.25516,382
67156.16.128.0/18156.16.128.1 to 156.16.191.254156.16.191.25516,382
68156.16.192.0/18156.16.192.1 to 156.16.255.254156.16.255.25516,382
69156.17.0.0/18156.17.0.1 to 156.17.63.254156.17.63.25516,382
70156.17.64.0/18156.17.64.1 to 156.17.127.254156.17.127.25516,382
71156.17.128.0/18156.17.128.1 to 156.17.191.254156.17.191.25516,382
72156.17.192.0/18156.17.192.1 to 156.17.255.254156.17.255.25516,382
73156.18.0.0/18156.18.0.1 to 156.18.63.254156.18.63.25516,382
74156.18.64.0/18156.18.64.1 to 156.18.127.254156.18.127.25516,382
75156.18.128.0/18156.18.128.1 to 156.18.191.254156.18.191.25516,382
76156.18.192.0/18156.18.192.1 to 156.18.255.254156.18.255.25516,382
77156.19.0.0/18156.19.0.1 to 156.19.63.254156.19.63.25516,382
78156.19.64.0/18156.19.64.1 to 156.19.127.254156.19.127.25516,382
79156.19.128.0/18156.19.128.1 to 156.19.191.254156.19.191.25516,382
80156.19.192.0/18156.19.192.1 to 156.19.255.254156.19.255.25516,382
81156.20.0.0/18156.20.0.1 to 156.20.63.254156.20.63.25516,382
82156.20.64.0/18156.20.64.1 to 156.20.127.254156.20.127.25516,382
83156.20.128.0/18156.20.128.1 to 156.20.191.254156.20.191.25516,382
84156.20.192.0/18156.20.192.1 to 156.20.255.254156.20.255.25516,382
85156.21.0.0/18156.21.0.1 to 156.21.63.254156.21.63.25516,382
86156.21.64.0/18156.21.64.1 to 156.21.127.254156.21.127.25516,382
87156.21.128.0/18156.21.128.1 to 156.21.191.254156.21.191.25516,382
88156.21.192.0/18156.21.192.1 to 156.21.255.254156.21.255.25516,382
89156.22.0.0/18156.22.0.1 to 156.22.63.254156.22.63.25516,382
90156.22.64.0/18156.22.64.1 to 156.22.127.254156.22.127.25516,382
91156.22.128.0/18156.22.128.1 to 156.22.191.254156.22.191.25516,382
92156.22.192.0/18156.22.192.1 to 156.22.255.254156.22.255.25516,382
93156.23.0.0/18156.23.0.1 to 156.23.63.254156.23.63.25516,382
94156.23.64.0/18156.23.64.1 to 156.23.127.254156.23.127.25516,382
95156.23.128.0/18156.23.128.1 to 156.23.191.254156.23.191.25516,382
96156.23.192.0/18156.23.192.1 to 156.23.255.254156.23.255.25516,382
97156.24.0.0/18156.24.0.1 to 156.24.63.254156.24.63.25516,382
98156.24.64.0/18156.24.64.1 to 156.24.127.254156.24.127.25516,382
99156.24.128.0/18156.24.128.1 to 156.24.191.254156.24.191.25516,382
100156.24.192.0/18156.24.192.1 to 156.24.255.254156.24.255.25516,382
101156.25.0.0/18156.25.0.1 to 156.25.63.254156.25.63.25516,382
102156.25.64.0/18156.25.64.1 to 156.25.127.254156.25.127.25516,382
103156.25.128.0/18156.25.128.1 to 156.25.191.254156.25.191.25516,382
104156.25.192.0/18156.25.192.1 to 156.25.255.254156.25.255.25516,382
105156.26.0.0/18156.26.0.1 to 156.26.63.254156.26.63.25516,382
106156.26.64.0/18156.26.64.1 to 156.26.127.254156.26.127.25516,382
107156.26.128.0/18156.26.128.1 to 156.26.191.254156.26.191.25516,382
108156.26.192.0/18156.26.192.1 to 156.26.255.254156.26.255.25516,382
109156.27.0.0/18156.27.0.1 to 156.27.63.254156.27.63.25516,382
110156.27.64.0/18156.27.64.1 to 156.27.127.254156.27.127.25516,382
111156.27.128.0/18156.27.128.1 to 156.27.191.254156.27.191.25516,382
112156.27.192.0/18156.27.192.1 to 156.27.255.254156.27.255.25516,382
113156.28.0.0/18156.28.0.1 to 156.28.63.254156.28.63.25516,382
114156.28.64.0/18156.28.64.1 to 156.28.127.254156.28.127.25516,382
115156.28.128.0/18156.28.128.1 to 156.28.191.254156.28.191.25516,382
116156.28.192.0/18156.28.192.1 to 156.28.255.254156.28.255.25516,382
117156.29.0.0/18156.29.0.1 to 156.29.63.254156.29.63.25516,382
118156.29.64.0/18156.29.64.1 to 156.29.127.254156.29.127.25516,382
119156.29.128.0/18156.29.128.1 to 156.29.191.254156.29.191.25516,382
120156.29.192.0/18156.29.192.1 to 156.29.255.254156.29.255.25516,382
121156.30.0.0/18156.30.0.1 to 156.30.63.254156.30.63.25516,382
122156.30.64.0/18156.30.64.1 to 156.30.127.254156.30.127.25516,382
123156.30.128.0/18156.30.128.1 to 156.30.191.254156.30.191.25516,382
124156.30.192.0/18156.30.192.1 to 156.30.255.254156.30.255.25516,382
125156.31.0.0/18156.31.0.1 to 156.31.63.254156.31.63.25516,382
126156.31.64.0/18156.31.64.1 to 156.31.127.254156.31.127.25516,382
127156.31.128.0/18156.31.128.1 to 156.31.191.254156.31.191.25516,382
128156.31.192.0/18156.31.192.1 to 156.31.255.254156.31.255.25516,382
129156.32.0.0/18156.32.0.1 to 156.32.63.254156.32.63.25516,382
130156.32.64.0/18156.32.64.1 to 156.32.127.254156.32.127.25516,382
131156.32.128.0/18156.32.128.1 to 156.32.191.254156.32.191.25516,382
132156.32.192.0/18156.32.192.1 to 156.32.255.254156.32.255.25516,382
133156.33.0.0/18156.33.0.1 to 156.33.63.254156.33.63.25516,382
134156.33.64.0/18156.33.64.1 to 156.33.127.254156.33.127.25516,382
135156.33.128.0/18156.33.128.1 to 156.33.191.254156.33.191.25516,382
136156.33.192.0/18156.33.192.1 to 156.33.255.254156.33.255.25516,382
137156.34.0.0/18156.34.0.1 to 156.34.63.254156.34.63.25516,382
138156.34.64.0/18156.34.64.1 to 156.34.127.254156.34.127.25516,382
139156.34.128.0/18156.34.128.1 to 156.34.191.254156.34.191.25516,382
140156.34.192.0/18156.34.192.1 to 156.34.255.254156.34.255.25516,382
141156.35.0.0/18156.35.0.1 to 156.35.63.254156.35.63.25516,382
142156.35.64.0/18156.35.64.1 to 156.35.127.254156.35.127.25516,382
143156.35.128.0/18156.35.128.1 to 156.35.191.254156.35.191.25516,382
144156.35.192.0/18156.35.192.1 to 156.35.255.254156.35.255.25516,382
145156.36.0.0/18156.36.0.1 to 156.36.63.254156.36.63.25516,382
146156.36.64.0/18156.36.64.1 to 156.36.127.254156.36.127.25516,382
147156.36.128.0/18156.36.128.1 to 156.36.191.254156.36.191.25516,382
148156.36.192.0/18156.36.192.1 to 156.36.255.254156.36.255.25516,382
149156.37.0.0/18156.37.0.1 to 156.37.63.254156.37.63.25516,382
150156.37.64.0/18156.37.64.1 to 156.37.127.254156.37.127.25516,382
151156.37.128.0/18156.37.128.1 to 156.37.191.254156.37.191.25516,382
152156.37.192.0/18156.37.192.1 to 156.37.255.254156.37.255.25516,382
153156.38.0.0/18156.38.0.1 to 156.38.63.254156.38.63.25516,382
154156.38.64.0/18156.38.64.1 to 156.38.127.254156.38.127.25516,382
155156.38.128.0/18156.38.128.1 to 156.38.191.254156.38.191.25516,382
156156.38.192.0/18156.38.192.1 to 156.38.255.254156.38.255.25516,382
157156.39.0.0/18156.39.0.1 to 156.39.63.254156.39.63.25516,382
158156.39.64.0/18156.39.64.1 to 156.39.127.254156.39.127.25516,382
159156.39.128.0/18156.39.128.1 to 156.39.191.254156.39.191.25516,382
160156.39.192.0/18156.39.192.1 to 156.39.255.254156.39.255.25516,382
161156.40.0.0/18156.40.0.1 to 156.40.63.254156.40.63.25516,382
162156.40.64.0/18156.40.64.1 to 156.40.127.254156.40.127.25516,382
163156.40.128.0/18156.40.128.1 to 156.40.191.254156.40.191.25516,382
164156.40.192.0/18156.40.192.1 to 156.40.255.254156.40.255.25516,382
165156.41.0.0/18156.41.0.1 to 156.41.63.254156.41.63.25516,382
166156.41.64.0/18156.41.64.1 to 156.41.127.254156.41.127.25516,382
167156.41.128.0/18156.41.128.1 to 156.41.191.254156.41.191.25516,382
168156.41.192.0/18156.41.192.1 to 156.41.255.254156.41.255.25516,382
169156.42.0.0/18156.42.0.1 to 156.42.63.254156.42.63.25516,382
170156.42.64.0/18156.42.64.1 to 156.42.127.254156.42.127.25516,382
171156.42.128.0/18156.42.128.1 to 156.42.191.254156.42.191.25516,382
172156.42.192.0/18156.42.192.1 to 156.42.255.254156.42.255.25516,382
173156.43.0.0/18156.43.0.1 to 156.43.63.254156.43.63.25516,382
174156.43.64.0/18156.43.64.1 to 156.43.127.254156.43.127.25516,382
175156.43.128.0/18156.43.128.1 to 156.43.191.254156.43.191.25516,382
176156.43.192.0/18156.43.192.1 to 156.43.255.254156.43.255.25516,382
177156.44.0.0/18156.44.0.1 to 156.44.63.254156.44.63.25516,382
178156.44.64.0/18156.44.64.1 to 156.44.127.254156.44.127.25516,382
179156.44.128.0/18156.44.128.1 to 156.44.191.254156.44.191.25516,382
180156.44.192.0/18156.44.192.1 to 156.44.255.254156.44.255.25516,382
181156.45.0.0/18156.45.0.1 to 156.45.63.254156.45.63.25516,382
182156.45.64.0/18156.45.64.1 to 156.45.127.254156.45.127.25516,382
183156.45.128.0/18156.45.128.1 to 156.45.191.254156.45.191.25516,382
184156.45.192.0/18156.45.192.1 to 156.45.255.254156.45.255.25516,382
185156.46.0.0/18156.46.0.1 to 156.46.63.254156.46.63.25516,382
186156.46.64.0/18156.46.64.1 to 156.46.127.254156.46.127.25516,382
187156.46.128.0/18156.46.128.1 to 156.46.191.254156.46.191.25516,382
188156.46.192.0/18156.46.192.1 to 156.46.255.254156.46.255.25516,382
189156.47.0.0/18156.47.0.1 to 156.47.63.254156.47.63.25516,382
190156.47.64.0/18156.47.64.1 to 156.47.127.254156.47.127.25516,382
191156.47.128.0/18156.47.128.1 to 156.47.191.254156.47.191.25516,382
192156.47.192.0/18156.47.192.1 to 156.47.255.254156.47.255.25516,382
193156.48.0.0/18156.48.0.1 to 156.48.63.254156.48.63.25516,382
194156.48.64.0/18156.48.64.1 to 156.48.127.254156.48.127.25516,382
195156.48.128.0/18156.48.128.1 to 156.48.191.254156.48.191.25516,382
196156.48.192.0/18156.48.192.1 to 156.48.255.254156.48.255.25516,382
197156.49.0.0/18156.49.0.1 to 156.49.63.254156.49.63.25516,382
198156.49.64.0/18156.49.64.1 to 156.49.127.254156.49.127.25516,382
199156.49.128.0/18156.49.128.1 to 156.49.191.254156.49.191.25516,382
200156.49.192.0/18156.49.192.1 to 156.49.255.254156.49.255.25516,382
201156.50.0.0/18156.50.0.1 to 156.50.63.254156.50.63.25516,382
202156.50.64.0/18156.50.64.1 to 156.50.127.254156.50.127.25516,382
203156.50.128.0/18156.50.128.1 to 156.50.191.254156.50.191.25516,382
204156.50.192.0/18156.50.192.1 to 156.50.255.254156.50.255.25516,382
205156.51.0.0/18156.51.0.1 to 156.51.63.254156.51.63.25516,382
206156.51.64.0/18156.51.64.1 to 156.51.127.254156.51.127.25516,382
207156.51.128.0/18156.51.128.1 to 156.51.191.254156.51.191.25516,382
208156.51.192.0/18156.51.192.1 to 156.51.255.254156.51.255.25516,382
209156.52.0.0/18156.52.0.1 to 156.52.63.254156.52.63.25516,382
210156.52.64.0/18156.52.64.1 to 156.52.127.254156.52.127.25516,382
211156.52.128.0/18156.52.128.1 to 156.52.191.254156.52.191.25516,382
212156.52.192.0/18156.52.192.1 to 156.52.255.254156.52.255.25516,382
213156.53.0.0/18156.53.0.1 to 156.53.63.254156.53.63.25516,382
214156.53.64.0/18156.53.64.1 to 156.53.127.254156.53.127.25516,382
215156.53.128.0/18156.53.128.1 to 156.53.191.254156.53.191.25516,382
216156.53.192.0/18156.53.192.1 to 156.53.255.254156.53.255.25516,382
217156.54.0.0/18156.54.0.1 to 156.54.63.254156.54.63.25516,382
218156.54.64.0/18156.54.64.1 to 156.54.127.254156.54.127.25516,382
219156.54.128.0/18156.54.128.1 to 156.54.191.254156.54.191.25516,382
220156.54.192.0/18156.54.192.1 to 156.54.255.254156.54.255.25516,382
221156.55.0.0/18156.55.0.1 to 156.55.63.254156.55.63.25516,382
222156.55.64.0/18156.55.64.1 to 156.55.127.254156.55.127.25516,382
223156.55.128.0/18156.55.128.1 to 156.55.191.254156.55.191.25516,382
224156.55.192.0/18156.55.192.1 to 156.55.255.254156.55.255.25516,382
225156.56.0.0/18156.56.0.1 to 156.56.63.254156.56.63.25516,382
226156.56.64.0/18156.56.64.1 to 156.56.127.254156.56.127.25516,382
227156.56.128.0/18156.56.128.1 to 156.56.191.254156.56.191.25516,382
228156.56.192.0/18156.56.192.1 to 156.56.255.254156.56.255.25516,382
229156.57.0.0/18156.57.0.1 to 156.57.63.254156.57.63.25516,382
230156.57.64.0/18156.57.64.1 to 156.57.127.254156.57.127.25516,382
231156.57.128.0/18156.57.128.1 to 156.57.191.254156.57.191.25516,382
232156.57.192.0/18156.57.192.1 to 156.57.255.254156.57.255.25516,382
233156.58.0.0/18156.58.0.1 to 156.58.63.254156.58.63.25516,382
234156.58.64.0/18156.58.64.1 to 156.58.127.254156.58.127.25516,382
235156.58.128.0/18156.58.128.1 to 156.58.191.254156.58.191.25516,382
236156.58.192.0/18156.58.192.1 to 156.58.255.254156.58.255.25516,382
237156.59.0.0/18156.59.0.1 to 156.59.63.254156.59.63.25516,382
238156.59.64.0/18156.59.64.1 to 156.59.127.254156.59.127.25516,382
239156.59.128.0/18156.59.128.1 to 156.59.191.254156.59.191.25516,382
240156.59.192.0/18156.59.192.1 to 156.59.255.254156.59.255.25516,382
241156.60.0.0/18156.60.0.1 to 156.60.63.254156.60.63.25516,382
242156.60.64.0/18156.60.64.1 to 156.60.127.254156.60.127.25516,382
243156.60.128.0/18156.60.128.1 to 156.60.191.254156.60.191.25516,382
244156.60.192.0/18156.60.192.1 to 156.60.255.254156.60.255.25516,382
245156.61.0.0/18156.61.0.1 to 156.61.63.254156.61.63.25516,382
246156.61.64.0/18156.61.64.1 to 156.61.127.254156.61.127.25516,382
247156.61.128.0/18156.61.128.1 to 156.61.191.254156.61.191.25516,382
248156.61.192.0/18156.61.192.1 to 156.61.255.254156.61.255.25516,382
249156.62.0.0/18156.62.0.1 to 156.62.63.254156.62.63.25516,382
250156.62.64.0/18156.62.64.1 to 156.62.127.254156.62.127.25516,382
251156.62.128.0/18156.62.128.1 to 156.62.191.254156.62.191.25516,382
252156.62.192.0/18156.62.192.1 to 156.62.255.254156.62.255.25516,382
253156.63.0.0/18156.63.0.1 to 156.63.63.254156.63.63.25516,382
254156.63.64.0/18156.63.64.1 to 156.63.127.254156.63.127.25516,382
255156.63.128.0/18156.63.128.1 to 156.63.191.254156.63.191.25516,382
256156.63.192.0/18156.63.192.1 to 156.63.255.254156.63.255.25516,382

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.