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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.

Network183.7.0.0/17
Usable hosts32,766
Subnet mask255.255.128.0
Addresses32,768
Network address
183.7.0.0
Broadcast address
183.7.127.255
First usable
183.7.0.1
Last usable
183.7.127.254
Usable hosts
32,766 (32,768 less the network and broadcast addresses)
Subnet mask
255.255.128.0
Wildcard mask
0.0.127.255 (Cisco ACLs, OSPF)
Prefix length
/17
Type
Public public
Old class
B (default /16)
As numbers
Hex B7070000 · Integer 3070689280 to 3070722047
Reverse DNS zones
0.7.183.in-addr.arpa
1.7.183.in-addr.arpa
2.7.183.in-addr.arpa
3.7.183.in-addr.arpa
4.7.183.in-addr.arpa
5.7.183.in-addr.arpa
6.7.183.in-addr.arpa
7.7.183.in-addr.arpa
8.7.183.in-addr.arpa
9.7.183.in-addr.arpa
10.7.183.in-addr.arpa
11.7.183.in-addr.arpa
12.7.183.in-addr.arpa
13.7.183.in-addr.arpa
14.7.183.in-addr.arpa
15.7.183.in-addr.arpa
and 112 more
/17 is not on a 8-bit boundary, so it takes 128 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10110111.00000111.00000000.00000000183.7.0.0
Subnet mask11111111.11111111.10000000.00000000255.255.128.0
Network10110111.00000111.00000000.00000000183.7.0.0
Broadcast10110111.00000111.01111111.11111111183.7.127.255
Split into smaller subnets/28
/18 (2)/19 (4)/20 (8)/21 (16)/22 (32)/23 (64)/24 (128)/25 (256)/26 (512)/27 (1,024)/28 (2,048)/29 (4,096)

183.7.0.0/17 makes 2,048 subnets of /28; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1183.7.0.0/28183.7.0.1 to 183.7.0.14183.7.0.1514
2183.7.0.16/28183.7.0.17 to 183.7.0.30183.7.0.3114
3183.7.0.32/28183.7.0.33 to 183.7.0.46183.7.0.4714
4183.7.0.48/28183.7.0.49 to 183.7.0.62183.7.0.6314
5183.7.0.64/28183.7.0.65 to 183.7.0.78183.7.0.7914
6183.7.0.80/28183.7.0.81 to 183.7.0.94183.7.0.9514
7183.7.0.96/28183.7.0.97 to 183.7.0.110183.7.0.11114
8183.7.0.112/28183.7.0.113 to 183.7.0.126183.7.0.12714
9183.7.0.128/28183.7.0.129 to 183.7.0.142183.7.0.14314
10183.7.0.144/28183.7.0.145 to 183.7.0.158183.7.0.15914
11183.7.0.160/28183.7.0.161 to 183.7.0.174183.7.0.17514
12183.7.0.176/28183.7.0.177 to 183.7.0.190183.7.0.19114
13183.7.0.192/28183.7.0.193 to 183.7.0.206183.7.0.20714
14183.7.0.208/28183.7.0.209 to 183.7.0.222183.7.0.22314
15183.7.0.224/28183.7.0.225 to 183.7.0.238183.7.0.23914
16183.7.0.240/28183.7.0.241 to 183.7.0.254183.7.0.25514
17183.7.1.0/28183.7.1.1 to 183.7.1.14183.7.1.1514
18183.7.1.16/28183.7.1.17 to 183.7.1.30183.7.1.3114
19183.7.1.32/28183.7.1.33 to 183.7.1.46183.7.1.4714
20183.7.1.48/28183.7.1.49 to 183.7.1.62183.7.1.6314
21183.7.1.64/28183.7.1.65 to 183.7.1.78183.7.1.7914
22183.7.1.80/28183.7.1.81 to 183.7.1.94183.7.1.9514
23183.7.1.96/28183.7.1.97 to 183.7.1.110183.7.1.11114
24183.7.1.112/28183.7.1.113 to 183.7.1.126183.7.1.12714
25183.7.1.128/28183.7.1.129 to 183.7.1.142183.7.1.14314
26183.7.1.144/28183.7.1.145 to 183.7.1.158183.7.1.15914
27183.7.1.160/28183.7.1.161 to 183.7.1.174183.7.1.17514
28183.7.1.176/28183.7.1.177 to 183.7.1.190183.7.1.19114
29183.7.1.192/28183.7.1.193 to 183.7.1.206183.7.1.20714
30183.7.1.208/28183.7.1.209 to 183.7.1.222183.7.1.22314
31183.7.1.224/28183.7.1.225 to 183.7.1.238183.7.1.23914
32183.7.1.240/28183.7.1.241 to 183.7.1.254183.7.1.25514
33183.7.2.0/28183.7.2.1 to 183.7.2.14183.7.2.1514
34183.7.2.16/28183.7.2.17 to 183.7.2.30183.7.2.3114
35183.7.2.32/28183.7.2.33 to 183.7.2.46183.7.2.4714
36183.7.2.48/28183.7.2.49 to 183.7.2.62183.7.2.6314
37183.7.2.64/28183.7.2.65 to 183.7.2.78183.7.2.7914
38183.7.2.80/28183.7.2.81 to 183.7.2.94183.7.2.9514
39183.7.2.96/28183.7.2.97 to 183.7.2.110183.7.2.11114
40183.7.2.112/28183.7.2.113 to 183.7.2.126183.7.2.12714
41183.7.2.128/28183.7.2.129 to 183.7.2.142183.7.2.14314
42183.7.2.144/28183.7.2.145 to 183.7.2.158183.7.2.15914
43183.7.2.160/28183.7.2.161 to 183.7.2.174183.7.2.17514
44183.7.2.176/28183.7.2.177 to 183.7.2.190183.7.2.19114
45183.7.2.192/28183.7.2.193 to 183.7.2.206183.7.2.20714
46183.7.2.208/28183.7.2.209 to 183.7.2.222183.7.2.22314
47183.7.2.224/28183.7.2.225 to 183.7.2.238183.7.2.23914
48183.7.2.240/28183.7.2.241 to 183.7.2.254183.7.2.25514
49183.7.3.0/28183.7.3.1 to 183.7.3.14183.7.3.1514
50183.7.3.16/28183.7.3.17 to 183.7.3.30183.7.3.3114
51183.7.3.32/28183.7.3.33 to 183.7.3.46183.7.3.4714
52183.7.3.48/28183.7.3.49 to 183.7.3.62183.7.3.6314
53183.7.3.64/28183.7.3.65 to 183.7.3.78183.7.3.7914
54183.7.3.80/28183.7.3.81 to 183.7.3.94183.7.3.9514
55183.7.3.96/28183.7.3.97 to 183.7.3.110183.7.3.11114
56183.7.3.112/28183.7.3.113 to 183.7.3.126183.7.3.12714
57183.7.3.128/28183.7.3.129 to 183.7.3.142183.7.3.14314
58183.7.3.144/28183.7.3.145 to 183.7.3.158183.7.3.15914
59183.7.3.160/28183.7.3.161 to 183.7.3.174183.7.3.17514
60183.7.3.176/28183.7.3.177 to 183.7.3.190183.7.3.19114
61183.7.3.192/28183.7.3.193 to 183.7.3.206183.7.3.20714
62183.7.3.208/28183.7.3.209 to 183.7.3.222183.7.3.22314
63183.7.3.224/28183.7.3.225 to 183.7.3.238183.7.3.23914
64183.7.3.240/28183.7.3.241 to 183.7.3.254183.7.3.25514
65183.7.4.0/28183.7.4.1 to 183.7.4.14183.7.4.1514
66183.7.4.16/28183.7.4.17 to 183.7.4.30183.7.4.3114
67183.7.4.32/28183.7.4.33 to 183.7.4.46183.7.4.4714
68183.7.4.48/28183.7.4.49 to 183.7.4.62183.7.4.6314
69183.7.4.64/28183.7.4.65 to 183.7.4.78183.7.4.7914
70183.7.4.80/28183.7.4.81 to 183.7.4.94183.7.4.9514
71183.7.4.96/28183.7.4.97 to 183.7.4.110183.7.4.11114
72183.7.4.112/28183.7.4.113 to 183.7.4.126183.7.4.12714
73183.7.4.128/28183.7.4.129 to 183.7.4.142183.7.4.14314
74183.7.4.144/28183.7.4.145 to 183.7.4.158183.7.4.15914
75183.7.4.160/28183.7.4.161 to 183.7.4.174183.7.4.17514
76183.7.4.176/28183.7.4.177 to 183.7.4.190183.7.4.19114
77183.7.4.192/28183.7.4.193 to 183.7.4.206183.7.4.20714
78183.7.4.208/28183.7.4.209 to 183.7.4.222183.7.4.22314
79183.7.4.224/28183.7.4.225 to 183.7.4.238183.7.4.23914
80183.7.4.240/28183.7.4.241 to 183.7.4.254183.7.4.25514
81183.7.5.0/28183.7.5.1 to 183.7.5.14183.7.5.1514
82183.7.5.16/28183.7.5.17 to 183.7.5.30183.7.5.3114
83183.7.5.32/28183.7.5.33 to 183.7.5.46183.7.5.4714
84183.7.5.48/28183.7.5.49 to 183.7.5.62183.7.5.6314
85183.7.5.64/28183.7.5.65 to 183.7.5.78183.7.5.7914
86183.7.5.80/28183.7.5.81 to 183.7.5.94183.7.5.9514
87183.7.5.96/28183.7.5.97 to 183.7.5.110183.7.5.11114
88183.7.5.112/28183.7.5.113 to 183.7.5.126183.7.5.12714
89183.7.5.128/28183.7.5.129 to 183.7.5.142183.7.5.14314
90183.7.5.144/28183.7.5.145 to 183.7.5.158183.7.5.15914
91183.7.5.160/28183.7.5.161 to 183.7.5.174183.7.5.17514
92183.7.5.176/28183.7.5.177 to 183.7.5.190183.7.5.19114
93183.7.5.192/28183.7.5.193 to 183.7.5.206183.7.5.20714
94183.7.5.208/28183.7.5.209 to 183.7.5.222183.7.5.22314
95183.7.5.224/28183.7.5.225 to 183.7.5.238183.7.5.23914
96183.7.5.240/28183.7.5.241 to 183.7.5.254183.7.5.25514
97183.7.6.0/28183.7.6.1 to 183.7.6.14183.7.6.1514
98183.7.6.16/28183.7.6.17 to 183.7.6.30183.7.6.3114
99183.7.6.32/28183.7.6.33 to 183.7.6.46183.7.6.4714
100183.7.6.48/28183.7.6.49 to 183.7.6.62183.7.6.6314
101183.7.6.64/28183.7.6.65 to 183.7.6.78183.7.6.7914
102183.7.6.80/28183.7.6.81 to 183.7.6.94183.7.6.9514
103183.7.6.96/28183.7.6.97 to 183.7.6.110183.7.6.11114
104183.7.6.112/28183.7.6.113 to 183.7.6.126183.7.6.12714
105183.7.6.128/28183.7.6.129 to 183.7.6.142183.7.6.14314
106183.7.6.144/28183.7.6.145 to 183.7.6.158183.7.6.15914
107183.7.6.160/28183.7.6.161 to 183.7.6.174183.7.6.17514
108183.7.6.176/28183.7.6.177 to 183.7.6.190183.7.6.19114
109183.7.6.192/28183.7.6.193 to 183.7.6.206183.7.6.20714
110183.7.6.208/28183.7.6.209 to 183.7.6.222183.7.6.22314
111183.7.6.224/28183.7.6.225 to 183.7.6.238183.7.6.23914
112183.7.6.240/28183.7.6.241 to 183.7.6.254183.7.6.25514
113183.7.7.0/28183.7.7.1 to 183.7.7.14183.7.7.1514
114183.7.7.16/28183.7.7.17 to 183.7.7.30183.7.7.3114
115183.7.7.32/28183.7.7.33 to 183.7.7.46183.7.7.4714
116183.7.7.48/28183.7.7.49 to 183.7.7.62183.7.7.6314
117183.7.7.64/28183.7.7.65 to 183.7.7.78183.7.7.7914
118183.7.7.80/28183.7.7.81 to 183.7.7.94183.7.7.9514
119183.7.7.96/28183.7.7.97 to 183.7.7.110183.7.7.11114
120183.7.7.112/28183.7.7.113 to 183.7.7.126183.7.7.12714
121183.7.7.128/28183.7.7.129 to 183.7.7.142183.7.7.14314
122183.7.7.144/28183.7.7.145 to 183.7.7.158183.7.7.15914
123183.7.7.160/28183.7.7.161 to 183.7.7.174183.7.7.17514
124183.7.7.176/28183.7.7.177 to 183.7.7.190183.7.7.19114
125183.7.7.192/28183.7.7.193 to 183.7.7.206183.7.7.20714
126183.7.7.208/28183.7.7.209 to 183.7.7.222183.7.7.22314
127183.7.7.224/28183.7.7.225 to 183.7.7.238183.7.7.23914
128183.7.7.240/28183.7.7.241 to 183.7.7.254183.7.7.25514
129183.7.8.0/28183.7.8.1 to 183.7.8.14183.7.8.1514
130183.7.8.16/28183.7.8.17 to 183.7.8.30183.7.8.3114
131183.7.8.32/28183.7.8.33 to 183.7.8.46183.7.8.4714
132183.7.8.48/28183.7.8.49 to 183.7.8.62183.7.8.6314
133183.7.8.64/28183.7.8.65 to 183.7.8.78183.7.8.7914
134183.7.8.80/28183.7.8.81 to 183.7.8.94183.7.8.9514
135183.7.8.96/28183.7.8.97 to 183.7.8.110183.7.8.11114
136183.7.8.112/28183.7.8.113 to 183.7.8.126183.7.8.12714
137183.7.8.128/28183.7.8.129 to 183.7.8.142183.7.8.14314
138183.7.8.144/28183.7.8.145 to 183.7.8.158183.7.8.15914
139183.7.8.160/28183.7.8.161 to 183.7.8.174183.7.8.17514
140183.7.8.176/28183.7.8.177 to 183.7.8.190183.7.8.19114
141183.7.8.192/28183.7.8.193 to 183.7.8.206183.7.8.20714
142183.7.8.208/28183.7.8.209 to 183.7.8.222183.7.8.22314
143183.7.8.224/28183.7.8.225 to 183.7.8.238183.7.8.23914
144183.7.8.240/28183.7.8.241 to 183.7.8.254183.7.8.25514
145183.7.9.0/28183.7.9.1 to 183.7.9.14183.7.9.1514
146183.7.9.16/28183.7.9.17 to 183.7.9.30183.7.9.3114
147183.7.9.32/28183.7.9.33 to 183.7.9.46183.7.9.4714
148183.7.9.48/28183.7.9.49 to 183.7.9.62183.7.9.6314
149183.7.9.64/28183.7.9.65 to 183.7.9.78183.7.9.7914
150183.7.9.80/28183.7.9.81 to 183.7.9.94183.7.9.9514
151183.7.9.96/28183.7.9.97 to 183.7.9.110183.7.9.11114
152183.7.9.112/28183.7.9.113 to 183.7.9.126183.7.9.12714
153183.7.9.128/28183.7.9.129 to 183.7.9.142183.7.9.14314
154183.7.9.144/28183.7.9.145 to 183.7.9.158183.7.9.15914
155183.7.9.160/28183.7.9.161 to 183.7.9.174183.7.9.17514
156183.7.9.176/28183.7.9.177 to 183.7.9.190183.7.9.19114
157183.7.9.192/28183.7.9.193 to 183.7.9.206183.7.9.20714
158183.7.9.208/28183.7.9.209 to 183.7.9.222183.7.9.22314
159183.7.9.224/28183.7.9.225 to 183.7.9.238183.7.9.23914
160183.7.9.240/28183.7.9.241 to 183.7.9.254183.7.9.25514
161183.7.10.0/28183.7.10.1 to 183.7.10.14183.7.10.1514
162183.7.10.16/28183.7.10.17 to 183.7.10.30183.7.10.3114
163183.7.10.32/28183.7.10.33 to 183.7.10.46183.7.10.4714
164183.7.10.48/28183.7.10.49 to 183.7.10.62183.7.10.6314
165183.7.10.64/28183.7.10.65 to 183.7.10.78183.7.10.7914
166183.7.10.80/28183.7.10.81 to 183.7.10.94183.7.10.9514
167183.7.10.96/28183.7.10.97 to 183.7.10.110183.7.10.11114
168183.7.10.112/28183.7.10.113 to 183.7.10.126183.7.10.12714
169183.7.10.128/28183.7.10.129 to 183.7.10.142183.7.10.14314
170183.7.10.144/28183.7.10.145 to 183.7.10.158183.7.10.15914
171183.7.10.160/28183.7.10.161 to 183.7.10.174183.7.10.17514
172183.7.10.176/28183.7.10.177 to 183.7.10.190183.7.10.19114
173183.7.10.192/28183.7.10.193 to 183.7.10.206183.7.10.20714
174183.7.10.208/28183.7.10.209 to 183.7.10.222183.7.10.22314
175183.7.10.224/28183.7.10.225 to 183.7.10.238183.7.10.23914
176183.7.10.240/28183.7.10.241 to 183.7.10.254183.7.10.25514
177183.7.11.0/28183.7.11.1 to 183.7.11.14183.7.11.1514
178183.7.11.16/28183.7.11.17 to 183.7.11.30183.7.11.3114
179183.7.11.32/28183.7.11.33 to 183.7.11.46183.7.11.4714
180183.7.11.48/28183.7.11.49 to 183.7.11.62183.7.11.6314
181183.7.11.64/28183.7.11.65 to 183.7.11.78183.7.11.7914
182183.7.11.80/28183.7.11.81 to 183.7.11.94183.7.11.9514
183183.7.11.96/28183.7.11.97 to 183.7.11.110183.7.11.11114
184183.7.11.112/28183.7.11.113 to 183.7.11.126183.7.11.12714
185183.7.11.128/28183.7.11.129 to 183.7.11.142183.7.11.14314
186183.7.11.144/28183.7.11.145 to 183.7.11.158183.7.11.15914
187183.7.11.160/28183.7.11.161 to 183.7.11.174183.7.11.17514
188183.7.11.176/28183.7.11.177 to 183.7.11.190183.7.11.19114
189183.7.11.192/28183.7.11.193 to 183.7.11.206183.7.11.20714
190183.7.11.208/28183.7.11.209 to 183.7.11.222183.7.11.22314
191183.7.11.224/28183.7.11.225 to 183.7.11.238183.7.11.23914
192183.7.11.240/28183.7.11.241 to 183.7.11.254183.7.11.25514
193183.7.12.0/28183.7.12.1 to 183.7.12.14183.7.12.1514
194183.7.12.16/28183.7.12.17 to 183.7.12.30183.7.12.3114
195183.7.12.32/28183.7.12.33 to 183.7.12.46183.7.12.4714
196183.7.12.48/28183.7.12.49 to 183.7.12.62183.7.12.6314
197183.7.12.64/28183.7.12.65 to 183.7.12.78183.7.12.7914
198183.7.12.80/28183.7.12.81 to 183.7.12.94183.7.12.9514
199183.7.12.96/28183.7.12.97 to 183.7.12.110183.7.12.11114
200183.7.12.112/28183.7.12.113 to 183.7.12.126183.7.12.12714
201183.7.12.128/28183.7.12.129 to 183.7.12.142183.7.12.14314
202183.7.12.144/28183.7.12.145 to 183.7.12.158183.7.12.15914
203183.7.12.160/28183.7.12.161 to 183.7.12.174183.7.12.17514
204183.7.12.176/28183.7.12.177 to 183.7.12.190183.7.12.19114
205183.7.12.192/28183.7.12.193 to 183.7.12.206183.7.12.20714
206183.7.12.208/28183.7.12.209 to 183.7.12.222183.7.12.22314
207183.7.12.224/28183.7.12.225 to 183.7.12.238183.7.12.23914
208183.7.12.240/28183.7.12.241 to 183.7.12.254183.7.12.25514
209183.7.13.0/28183.7.13.1 to 183.7.13.14183.7.13.1514
210183.7.13.16/28183.7.13.17 to 183.7.13.30183.7.13.3114
211183.7.13.32/28183.7.13.33 to 183.7.13.46183.7.13.4714
212183.7.13.48/28183.7.13.49 to 183.7.13.62183.7.13.6314
213183.7.13.64/28183.7.13.65 to 183.7.13.78183.7.13.7914
214183.7.13.80/28183.7.13.81 to 183.7.13.94183.7.13.9514
215183.7.13.96/28183.7.13.97 to 183.7.13.110183.7.13.11114
216183.7.13.112/28183.7.13.113 to 183.7.13.126183.7.13.12714
217183.7.13.128/28183.7.13.129 to 183.7.13.142183.7.13.14314
218183.7.13.144/28183.7.13.145 to 183.7.13.158183.7.13.15914
219183.7.13.160/28183.7.13.161 to 183.7.13.174183.7.13.17514
220183.7.13.176/28183.7.13.177 to 183.7.13.190183.7.13.19114
221183.7.13.192/28183.7.13.193 to 183.7.13.206183.7.13.20714
222183.7.13.208/28183.7.13.209 to 183.7.13.222183.7.13.22314
223183.7.13.224/28183.7.13.225 to 183.7.13.238183.7.13.23914
224183.7.13.240/28183.7.13.241 to 183.7.13.254183.7.13.25514
225183.7.14.0/28183.7.14.1 to 183.7.14.14183.7.14.1514
226183.7.14.16/28183.7.14.17 to 183.7.14.30183.7.14.3114
227183.7.14.32/28183.7.14.33 to 183.7.14.46183.7.14.4714
228183.7.14.48/28183.7.14.49 to 183.7.14.62183.7.14.6314
229183.7.14.64/28183.7.14.65 to 183.7.14.78183.7.14.7914
230183.7.14.80/28183.7.14.81 to 183.7.14.94183.7.14.9514
231183.7.14.96/28183.7.14.97 to 183.7.14.110183.7.14.11114
232183.7.14.112/28183.7.14.113 to 183.7.14.126183.7.14.12714
233183.7.14.128/28183.7.14.129 to 183.7.14.142183.7.14.14314
234183.7.14.144/28183.7.14.145 to 183.7.14.158183.7.14.15914
235183.7.14.160/28183.7.14.161 to 183.7.14.174183.7.14.17514
236183.7.14.176/28183.7.14.177 to 183.7.14.190183.7.14.19114
237183.7.14.192/28183.7.14.193 to 183.7.14.206183.7.14.20714
238183.7.14.208/28183.7.14.209 to 183.7.14.222183.7.14.22314
239183.7.14.224/28183.7.14.225 to 183.7.14.238183.7.14.23914
240183.7.14.240/28183.7.14.241 to 183.7.14.254183.7.14.25514
241183.7.15.0/28183.7.15.1 to 183.7.15.14183.7.15.1514
242183.7.15.16/28183.7.15.17 to 183.7.15.30183.7.15.3114
243183.7.15.32/28183.7.15.33 to 183.7.15.46183.7.15.4714
244183.7.15.48/28183.7.15.49 to 183.7.15.62183.7.15.6314
245183.7.15.64/28183.7.15.65 to 183.7.15.78183.7.15.7914
246183.7.15.80/28183.7.15.81 to 183.7.15.94183.7.15.9514
247183.7.15.96/28183.7.15.97 to 183.7.15.110183.7.15.11114
248183.7.15.112/28183.7.15.113 to 183.7.15.126183.7.15.12714
249183.7.15.128/28183.7.15.129 to 183.7.15.142183.7.15.14314
250183.7.15.144/28183.7.15.145 to 183.7.15.158183.7.15.15914
251183.7.15.160/28183.7.15.161 to 183.7.15.174183.7.15.17514
252183.7.15.176/28183.7.15.177 to 183.7.15.190183.7.15.19114
253183.7.15.192/28183.7.15.193 to 183.7.15.206183.7.15.20714
254183.7.15.208/28183.7.15.209 to 183.7.15.222183.7.15.22314
255183.7.15.224/28183.7.15.225 to 183.7.15.238183.7.15.23914
256183.7.15.240/28183.7.15.241 to 183.7.15.254183.7.15.25514

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.