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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.

Network183.0.0.0/9
Usable hosts8,388,606
Subnet mask255.128.0.0
Addresses8,388,608
Network address
183.0.0.0
Broadcast address
183.127.255.255
First usable
183.0.0.1
Last usable
183.127.255.254
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 B7000000 · Integer 3070230528 to 3078619135
Reverse DNS zones
0.183.in-addr.arpa
1.183.in-addr.arpa
2.183.in-addr.arpa
3.183.in-addr.arpa
4.183.in-addr.arpa
5.183.in-addr.arpa
6.183.in-addr.arpa
7.183.in-addr.arpa
8.183.in-addr.arpa
9.183.in-addr.arpa
10.183.in-addr.arpa
11.183.in-addr.arpa
12.183.in-addr.arpa
13.183.in-addr.arpa
14.183.in-addr.arpa
15.183.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
Address10110111.00000000.00000000.00000000183.0.0.0
Subnet mask11111111.10000000.00000000.00000000255.128.0.0
Network10110111.00000000.00000000.00000000183.0.0.0
Broadcast10110111.01111111.11111111.11111111183.127.255.255
Split into smaller subnets/18
/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)

183.0.0.0/9 makes 512 subnets of /18; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1183.0.0.0/18183.0.0.1 to 183.0.63.254183.0.63.25516,382
2183.0.64.0/18183.0.64.1 to 183.0.127.254183.0.127.25516,382
3183.0.128.0/18183.0.128.1 to 183.0.191.254183.0.191.25516,382
4183.0.192.0/18183.0.192.1 to 183.0.255.254183.0.255.25516,382
5183.1.0.0/18183.1.0.1 to 183.1.63.254183.1.63.25516,382
6183.1.64.0/18183.1.64.1 to 183.1.127.254183.1.127.25516,382
7183.1.128.0/18183.1.128.1 to 183.1.191.254183.1.191.25516,382
8183.1.192.0/18183.1.192.1 to 183.1.255.254183.1.255.25516,382
9183.2.0.0/18183.2.0.1 to 183.2.63.254183.2.63.25516,382
10183.2.64.0/18183.2.64.1 to 183.2.127.254183.2.127.25516,382
11183.2.128.0/18183.2.128.1 to 183.2.191.254183.2.191.25516,382
12183.2.192.0/18183.2.192.1 to 183.2.255.254183.2.255.25516,382
13183.3.0.0/18183.3.0.1 to 183.3.63.254183.3.63.25516,382
14183.3.64.0/18183.3.64.1 to 183.3.127.254183.3.127.25516,382
15183.3.128.0/18183.3.128.1 to 183.3.191.254183.3.191.25516,382
16183.3.192.0/18183.3.192.1 to 183.3.255.254183.3.255.25516,382
17183.4.0.0/18183.4.0.1 to 183.4.63.254183.4.63.25516,382
18183.4.64.0/18183.4.64.1 to 183.4.127.254183.4.127.25516,382
19183.4.128.0/18183.4.128.1 to 183.4.191.254183.4.191.25516,382
20183.4.192.0/18183.4.192.1 to 183.4.255.254183.4.255.25516,382
21183.5.0.0/18183.5.0.1 to 183.5.63.254183.5.63.25516,382
22183.5.64.0/18183.5.64.1 to 183.5.127.254183.5.127.25516,382
23183.5.128.0/18183.5.128.1 to 183.5.191.254183.5.191.25516,382
24183.5.192.0/18183.5.192.1 to 183.5.255.254183.5.255.25516,382
25183.6.0.0/18183.6.0.1 to 183.6.63.254183.6.63.25516,382
26183.6.64.0/18183.6.64.1 to 183.6.127.254183.6.127.25516,382
27183.6.128.0/18183.6.128.1 to 183.6.191.254183.6.191.25516,382
28183.6.192.0/18183.6.192.1 to 183.6.255.254183.6.255.25516,382
29183.7.0.0/18183.7.0.1 to 183.7.63.254183.7.63.25516,382
30183.7.64.0/18183.7.64.1 to 183.7.127.254183.7.127.25516,382
31183.7.128.0/18183.7.128.1 to 183.7.191.254183.7.191.25516,382
32183.7.192.0/18183.7.192.1 to 183.7.255.254183.7.255.25516,382
33183.8.0.0/18183.8.0.1 to 183.8.63.254183.8.63.25516,382
34183.8.64.0/18183.8.64.1 to 183.8.127.254183.8.127.25516,382
35183.8.128.0/18183.8.128.1 to 183.8.191.254183.8.191.25516,382
36183.8.192.0/18183.8.192.1 to 183.8.255.254183.8.255.25516,382
37183.9.0.0/18183.9.0.1 to 183.9.63.254183.9.63.25516,382
38183.9.64.0/18183.9.64.1 to 183.9.127.254183.9.127.25516,382
39183.9.128.0/18183.9.128.1 to 183.9.191.254183.9.191.25516,382
40183.9.192.0/18183.9.192.1 to 183.9.255.254183.9.255.25516,382
41183.10.0.0/18183.10.0.1 to 183.10.63.254183.10.63.25516,382
42183.10.64.0/18183.10.64.1 to 183.10.127.254183.10.127.25516,382
43183.10.128.0/18183.10.128.1 to 183.10.191.254183.10.191.25516,382
44183.10.192.0/18183.10.192.1 to 183.10.255.254183.10.255.25516,382
45183.11.0.0/18183.11.0.1 to 183.11.63.254183.11.63.25516,382
46183.11.64.0/18183.11.64.1 to 183.11.127.254183.11.127.25516,382
47183.11.128.0/18183.11.128.1 to 183.11.191.254183.11.191.25516,382
48183.11.192.0/18183.11.192.1 to 183.11.255.254183.11.255.25516,382
49183.12.0.0/18183.12.0.1 to 183.12.63.254183.12.63.25516,382
50183.12.64.0/18183.12.64.1 to 183.12.127.254183.12.127.25516,382
51183.12.128.0/18183.12.128.1 to 183.12.191.254183.12.191.25516,382
52183.12.192.0/18183.12.192.1 to 183.12.255.254183.12.255.25516,382
53183.13.0.0/18183.13.0.1 to 183.13.63.254183.13.63.25516,382
54183.13.64.0/18183.13.64.1 to 183.13.127.254183.13.127.25516,382
55183.13.128.0/18183.13.128.1 to 183.13.191.254183.13.191.25516,382
56183.13.192.0/18183.13.192.1 to 183.13.255.254183.13.255.25516,382
57183.14.0.0/18183.14.0.1 to 183.14.63.254183.14.63.25516,382
58183.14.64.0/18183.14.64.1 to 183.14.127.254183.14.127.25516,382
59183.14.128.0/18183.14.128.1 to 183.14.191.254183.14.191.25516,382
60183.14.192.0/18183.14.192.1 to 183.14.255.254183.14.255.25516,382
61183.15.0.0/18183.15.0.1 to 183.15.63.254183.15.63.25516,382
62183.15.64.0/18183.15.64.1 to 183.15.127.254183.15.127.25516,382
63183.15.128.0/18183.15.128.1 to 183.15.191.254183.15.191.25516,382
64183.15.192.0/18183.15.192.1 to 183.15.255.254183.15.255.25516,382
65183.16.0.0/18183.16.0.1 to 183.16.63.254183.16.63.25516,382
66183.16.64.0/18183.16.64.1 to 183.16.127.254183.16.127.25516,382
67183.16.128.0/18183.16.128.1 to 183.16.191.254183.16.191.25516,382
68183.16.192.0/18183.16.192.1 to 183.16.255.254183.16.255.25516,382
69183.17.0.0/18183.17.0.1 to 183.17.63.254183.17.63.25516,382
70183.17.64.0/18183.17.64.1 to 183.17.127.254183.17.127.25516,382
71183.17.128.0/18183.17.128.1 to 183.17.191.254183.17.191.25516,382
72183.17.192.0/18183.17.192.1 to 183.17.255.254183.17.255.25516,382
73183.18.0.0/18183.18.0.1 to 183.18.63.254183.18.63.25516,382
74183.18.64.0/18183.18.64.1 to 183.18.127.254183.18.127.25516,382
75183.18.128.0/18183.18.128.1 to 183.18.191.254183.18.191.25516,382
76183.18.192.0/18183.18.192.1 to 183.18.255.254183.18.255.25516,382
77183.19.0.0/18183.19.0.1 to 183.19.63.254183.19.63.25516,382
78183.19.64.0/18183.19.64.1 to 183.19.127.254183.19.127.25516,382
79183.19.128.0/18183.19.128.1 to 183.19.191.254183.19.191.25516,382
80183.19.192.0/18183.19.192.1 to 183.19.255.254183.19.255.25516,382
81183.20.0.0/18183.20.0.1 to 183.20.63.254183.20.63.25516,382
82183.20.64.0/18183.20.64.1 to 183.20.127.254183.20.127.25516,382
83183.20.128.0/18183.20.128.1 to 183.20.191.254183.20.191.25516,382
84183.20.192.0/18183.20.192.1 to 183.20.255.254183.20.255.25516,382
85183.21.0.0/18183.21.0.1 to 183.21.63.254183.21.63.25516,382
86183.21.64.0/18183.21.64.1 to 183.21.127.254183.21.127.25516,382
87183.21.128.0/18183.21.128.1 to 183.21.191.254183.21.191.25516,382
88183.21.192.0/18183.21.192.1 to 183.21.255.254183.21.255.25516,382
89183.22.0.0/18183.22.0.1 to 183.22.63.254183.22.63.25516,382
90183.22.64.0/18183.22.64.1 to 183.22.127.254183.22.127.25516,382
91183.22.128.0/18183.22.128.1 to 183.22.191.254183.22.191.25516,382
92183.22.192.0/18183.22.192.1 to 183.22.255.254183.22.255.25516,382
93183.23.0.0/18183.23.0.1 to 183.23.63.254183.23.63.25516,382
94183.23.64.0/18183.23.64.1 to 183.23.127.254183.23.127.25516,382
95183.23.128.0/18183.23.128.1 to 183.23.191.254183.23.191.25516,382
96183.23.192.0/18183.23.192.1 to 183.23.255.254183.23.255.25516,382
97183.24.0.0/18183.24.0.1 to 183.24.63.254183.24.63.25516,382
98183.24.64.0/18183.24.64.1 to 183.24.127.254183.24.127.25516,382
99183.24.128.0/18183.24.128.1 to 183.24.191.254183.24.191.25516,382
100183.24.192.0/18183.24.192.1 to 183.24.255.254183.24.255.25516,382
101183.25.0.0/18183.25.0.1 to 183.25.63.254183.25.63.25516,382
102183.25.64.0/18183.25.64.1 to 183.25.127.254183.25.127.25516,382
103183.25.128.0/18183.25.128.1 to 183.25.191.254183.25.191.25516,382
104183.25.192.0/18183.25.192.1 to 183.25.255.254183.25.255.25516,382
105183.26.0.0/18183.26.0.1 to 183.26.63.254183.26.63.25516,382
106183.26.64.0/18183.26.64.1 to 183.26.127.254183.26.127.25516,382
107183.26.128.0/18183.26.128.1 to 183.26.191.254183.26.191.25516,382
108183.26.192.0/18183.26.192.1 to 183.26.255.254183.26.255.25516,382
109183.27.0.0/18183.27.0.1 to 183.27.63.254183.27.63.25516,382
110183.27.64.0/18183.27.64.1 to 183.27.127.254183.27.127.25516,382
111183.27.128.0/18183.27.128.1 to 183.27.191.254183.27.191.25516,382
112183.27.192.0/18183.27.192.1 to 183.27.255.254183.27.255.25516,382
113183.28.0.0/18183.28.0.1 to 183.28.63.254183.28.63.25516,382
114183.28.64.0/18183.28.64.1 to 183.28.127.254183.28.127.25516,382
115183.28.128.0/18183.28.128.1 to 183.28.191.254183.28.191.25516,382
116183.28.192.0/18183.28.192.1 to 183.28.255.254183.28.255.25516,382
117183.29.0.0/18183.29.0.1 to 183.29.63.254183.29.63.25516,382
118183.29.64.0/18183.29.64.1 to 183.29.127.254183.29.127.25516,382
119183.29.128.0/18183.29.128.1 to 183.29.191.254183.29.191.25516,382
120183.29.192.0/18183.29.192.1 to 183.29.255.254183.29.255.25516,382
121183.30.0.0/18183.30.0.1 to 183.30.63.254183.30.63.25516,382
122183.30.64.0/18183.30.64.1 to 183.30.127.254183.30.127.25516,382
123183.30.128.0/18183.30.128.1 to 183.30.191.254183.30.191.25516,382
124183.30.192.0/18183.30.192.1 to 183.30.255.254183.30.255.25516,382
125183.31.0.0/18183.31.0.1 to 183.31.63.254183.31.63.25516,382
126183.31.64.0/18183.31.64.1 to 183.31.127.254183.31.127.25516,382
127183.31.128.0/18183.31.128.1 to 183.31.191.254183.31.191.25516,382
128183.31.192.0/18183.31.192.1 to 183.31.255.254183.31.255.25516,382
129183.32.0.0/18183.32.0.1 to 183.32.63.254183.32.63.25516,382
130183.32.64.0/18183.32.64.1 to 183.32.127.254183.32.127.25516,382
131183.32.128.0/18183.32.128.1 to 183.32.191.254183.32.191.25516,382
132183.32.192.0/18183.32.192.1 to 183.32.255.254183.32.255.25516,382
133183.33.0.0/18183.33.0.1 to 183.33.63.254183.33.63.25516,382
134183.33.64.0/18183.33.64.1 to 183.33.127.254183.33.127.25516,382
135183.33.128.0/18183.33.128.1 to 183.33.191.254183.33.191.25516,382
136183.33.192.0/18183.33.192.1 to 183.33.255.254183.33.255.25516,382
137183.34.0.0/18183.34.0.1 to 183.34.63.254183.34.63.25516,382
138183.34.64.0/18183.34.64.1 to 183.34.127.254183.34.127.25516,382
139183.34.128.0/18183.34.128.1 to 183.34.191.254183.34.191.25516,382
140183.34.192.0/18183.34.192.1 to 183.34.255.254183.34.255.25516,382
141183.35.0.0/18183.35.0.1 to 183.35.63.254183.35.63.25516,382
142183.35.64.0/18183.35.64.1 to 183.35.127.254183.35.127.25516,382
143183.35.128.0/18183.35.128.1 to 183.35.191.254183.35.191.25516,382
144183.35.192.0/18183.35.192.1 to 183.35.255.254183.35.255.25516,382
145183.36.0.0/18183.36.0.1 to 183.36.63.254183.36.63.25516,382
146183.36.64.0/18183.36.64.1 to 183.36.127.254183.36.127.25516,382
147183.36.128.0/18183.36.128.1 to 183.36.191.254183.36.191.25516,382
148183.36.192.0/18183.36.192.1 to 183.36.255.254183.36.255.25516,382
149183.37.0.0/18183.37.0.1 to 183.37.63.254183.37.63.25516,382
150183.37.64.0/18183.37.64.1 to 183.37.127.254183.37.127.25516,382
151183.37.128.0/18183.37.128.1 to 183.37.191.254183.37.191.25516,382
152183.37.192.0/18183.37.192.1 to 183.37.255.254183.37.255.25516,382
153183.38.0.0/18183.38.0.1 to 183.38.63.254183.38.63.25516,382
154183.38.64.0/18183.38.64.1 to 183.38.127.254183.38.127.25516,382
155183.38.128.0/18183.38.128.1 to 183.38.191.254183.38.191.25516,382
156183.38.192.0/18183.38.192.1 to 183.38.255.254183.38.255.25516,382
157183.39.0.0/18183.39.0.1 to 183.39.63.254183.39.63.25516,382
158183.39.64.0/18183.39.64.1 to 183.39.127.254183.39.127.25516,382
159183.39.128.0/18183.39.128.1 to 183.39.191.254183.39.191.25516,382
160183.39.192.0/18183.39.192.1 to 183.39.255.254183.39.255.25516,382
161183.40.0.0/18183.40.0.1 to 183.40.63.254183.40.63.25516,382
162183.40.64.0/18183.40.64.1 to 183.40.127.254183.40.127.25516,382
163183.40.128.0/18183.40.128.1 to 183.40.191.254183.40.191.25516,382
164183.40.192.0/18183.40.192.1 to 183.40.255.254183.40.255.25516,382
165183.41.0.0/18183.41.0.1 to 183.41.63.254183.41.63.25516,382
166183.41.64.0/18183.41.64.1 to 183.41.127.254183.41.127.25516,382
167183.41.128.0/18183.41.128.1 to 183.41.191.254183.41.191.25516,382
168183.41.192.0/18183.41.192.1 to 183.41.255.254183.41.255.25516,382
169183.42.0.0/18183.42.0.1 to 183.42.63.254183.42.63.25516,382
170183.42.64.0/18183.42.64.1 to 183.42.127.254183.42.127.25516,382
171183.42.128.0/18183.42.128.1 to 183.42.191.254183.42.191.25516,382
172183.42.192.0/18183.42.192.1 to 183.42.255.254183.42.255.25516,382
173183.43.0.0/18183.43.0.1 to 183.43.63.254183.43.63.25516,382
174183.43.64.0/18183.43.64.1 to 183.43.127.254183.43.127.25516,382
175183.43.128.0/18183.43.128.1 to 183.43.191.254183.43.191.25516,382
176183.43.192.0/18183.43.192.1 to 183.43.255.254183.43.255.25516,382
177183.44.0.0/18183.44.0.1 to 183.44.63.254183.44.63.25516,382
178183.44.64.0/18183.44.64.1 to 183.44.127.254183.44.127.25516,382
179183.44.128.0/18183.44.128.1 to 183.44.191.254183.44.191.25516,382
180183.44.192.0/18183.44.192.1 to 183.44.255.254183.44.255.25516,382
181183.45.0.0/18183.45.0.1 to 183.45.63.254183.45.63.25516,382
182183.45.64.0/18183.45.64.1 to 183.45.127.254183.45.127.25516,382
183183.45.128.0/18183.45.128.1 to 183.45.191.254183.45.191.25516,382
184183.45.192.0/18183.45.192.1 to 183.45.255.254183.45.255.25516,382
185183.46.0.0/18183.46.0.1 to 183.46.63.254183.46.63.25516,382
186183.46.64.0/18183.46.64.1 to 183.46.127.254183.46.127.25516,382
187183.46.128.0/18183.46.128.1 to 183.46.191.254183.46.191.25516,382
188183.46.192.0/18183.46.192.1 to 183.46.255.254183.46.255.25516,382
189183.47.0.0/18183.47.0.1 to 183.47.63.254183.47.63.25516,382
190183.47.64.0/18183.47.64.1 to 183.47.127.254183.47.127.25516,382
191183.47.128.0/18183.47.128.1 to 183.47.191.254183.47.191.25516,382
192183.47.192.0/18183.47.192.1 to 183.47.255.254183.47.255.25516,382
193183.48.0.0/18183.48.0.1 to 183.48.63.254183.48.63.25516,382
194183.48.64.0/18183.48.64.1 to 183.48.127.254183.48.127.25516,382
195183.48.128.0/18183.48.128.1 to 183.48.191.254183.48.191.25516,382
196183.48.192.0/18183.48.192.1 to 183.48.255.254183.48.255.25516,382
197183.49.0.0/18183.49.0.1 to 183.49.63.254183.49.63.25516,382
198183.49.64.0/18183.49.64.1 to 183.49.127.254183.49.127.25516,382
199183.49.128.0/18183.49.128.1 to 183.49.191.254183.49.191.25516,382
200183.49.192.0/18183.49.192.1 to 183.49.255.254183.49.255.25516,382
201183.50.0.0/18183.50.0.1 to 183.50.63.254183.50.63.25516,382
202183.50.64.0/18183.50.64.1 to 183.50.127.254183.50.127.25516,382
203183.50.128.0/18183.50.128.1 to 183.50.191.254183.50.191.25516,382
204183.50.192.0/18183.50.192.1 to 183.50.255.254183.50.255.25516,382
205183.51.0.0/18183.51.0.1 to 183.51.63.254183.51.63.25516,382
206183.51.64.0/18183.51.64.1 to 183.51.127.254183.51.127.25516,382
207183.51.128.0/18183.51.128.1 to 183.51.191.254183.51.191.25516,382
208183.51.192.0/18183.51.192.1 to 183.51.255.254183.51.255.25516,382
209183.52.0.0/18183.52.0.1 to 183.52.63.254183.52.63.25516,382
210183.52.64.0/18183.52.64.1 to 183.52.127.254183.52.127.25516,382
211183.52.128.0/18183.52.128.1 to 183.52.191.254183.52.191.25516,382
212183.52.192.0/18183.52.192.1 to 183.52.255.254183.52.255.25516,382
213183.53.0.0/18183.53.0.1 to 183.53.63.254183.53.63.25516,382
214183.53.64.0/18183.53.64.1 to 183.53.127.254183.53.127.25516,382
215183.53.128.0/18183.53.128.1 to 183.53.191.254183.53.191.25516,382
216183.53.192.0/18183.53.192.1 to 183.53.255.254183.53.255.25516,382
217183.54.0.0/18183.54.0.1 to 183.54.63.254183.54.63.25516,382
218183.54.64.0/18183.54.64.1 to 183.54.127.254183.54.127.25516,382
219183.54.128.0/18183.54.128.1 to 183.54.191.254183.54.191.25516,382
220183.54.192.0/18183.54.192.1 to 183.54.255.254183.54.255.25516,382
221183.55.0.0/18183.55.0.1 to 183.55.63.254183.55.63.25516,382
222183.55.64.0/18183.55.64.1 to 183.55.127.254183.55.127.25516,382
223183.55.128.0/18183.55.128.1 to 183.55.191.254183.55.191.25516,382
224183.55.192.0/18183.55.192.1 to 183.55.255.254183.55.255.25516,382
225183.56.0.0/18183.56.0.1 to 183.56.63.254183.56.63.25516,382
226183.56.64.0/18183.56.64.1 to 183.56.127.254183.56.127.25516,382
227183.56.128.0/18183.56.128.1 to 183.56.191.254183.56.191.25516,382
228183.56.192.0/18183.56.192.1 to 183.56.255.254183.56.255.25516,382
229183.57.0.0/18183.57.0.1 to 183.57.63.254183.57.63.25516,382
230183.57.64.0/18183.57.64.1 to 183.57.127.254183.57.127.25516,382
231183.57.128.0/18183.57.128.1 to 183.57.191.254183.57.191.25516,382
232183.57.192.0/18183.57.192.1 to 183.57.255.254183.57.255.25516,382
233183.58.0.0/18183.58.0.1 to 183.58.63.254183.58.63.25516,382
234183.58.64.0/18183.58.64.1 to 183.58.127.254183.58.127.25516,382
235183.58.128.0/18183.58.128.1 to 183.58.191.254183.58.191.25516,382
236183.58.192.0/18183.58.192.1 to 183.58.255.254183.58.255.25516,382
237183.59.0.0/18183.59.0.1 to 183.59.63.254183.59.63.25516,382
238183.59.64.0/18183.59.64.1 to 183.59.127.254183.59.127.25516,382
239183.59.128.0/18183.59.128.1 to 183.59.191.254183.59.191.25516,382
240183.59.192.0/18183.59.192.1 to 183.59.255.254183.59.255.25516,382
241183.60.0.0/18183.60.0.1 to 183.60.63.254183.60.63.25516,382
242183.60.64.0/18183.60.64.1 to 183.60.127.254183.60.127.25516,382
243183.60.128.0/18183.60.128.1 to 183.60.191.254183.60.191.25516,382
244183.60.192.0/18183.60.192.1 to 183.60.255.254183.60.255.25516,382
245183.61.0.0/18183.61.0.1 to 183.61.63.254183.61.63.25516,382
246183.61.64.0/18183.61.64.1 to 183.61.127.254183.61.127.25516,382
247183.61.128.0/18183.61.128.1 to 183.61.191.254183.61.191.25516,382
248183.61.192.0/18183.61.192.1 to 183.61.255.254183.61.255.25516,382
249183.62.0.0/18183.62.0.1 to 183.62.63.254183.62.63.25516,382
250183.62.64.0/18183.62.64.1 to 183.62.127.254183.62.127.25516,382
251183.62.128.0/18183.62.128.1 to 183.62.191.254183.62.191.25516,382
252183.62.192.0/18183.62.192.1 to 183.62.255.254183.62.255.25516,382
253183.63.0.0/18183.63.0.1 to 183.63.63.254183.63.63.25516,382
254183.63.64.0/18183.63.64.1 to 183.63.127.254183.63.127.25516,382
255183.63.128.0/18183.63.128.1 to 183.63.191.254183.63.191.25516,382
256183.63.192.0/18183.63.192.1 to 183.63.255.254183.63.255.25516,382

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.