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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.

Network177.2.0.0/17
Usable hosts32,766
Subnet mask255.255.128.0
Addresses32,768
Network address
177.2.0.0
Broadcast address
177.2.127.255
First usable
177.2.0.1
Last usable
177.2.127.254
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 B1020000 · Integer 2969698304 to 2969731071
Reverse DNS zones
0.2.177.in-addr.arpa
1.2.177.in-addr.arpa
2.2.177.in-addr.arpa
3.2.177.in-addr.arpa
4.2.177.in-addr.arpa
5.2.177.in-addr.arpa
6.2.177.in-addr.arpa
7.2.177.in-addr.arpa
8.2.177.in-addr.arpa
9.2.177.in-addr.arpa
10.2.177.in-addr.arpa
11.2.177.in-addr.arpa
12.2.177.in-addr.arpa
13.2.177.in-addr.arpa
14.2.177.in-addr.arpa
15.2.177.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
Address10110001.00000010.00000000.00000000177.2.0.0
Subnet mask11111111.11111111.10000000.00000000255.255.128.0
Network10110001.00000010.00000000.00000000177.2.0.0
Broadcast10110001.00000010.01111111.11111111177.2.127.255
Split into smaller subnets/27
/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)

177.2.0.0/17 makes 1,024 subnets of /27; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1177.2.0.0/27177.2.0.1 to 177.2.0.30177.2.0.3130
2177.2.0.32/27177.2.0.33 to 177.2.0.62177.2.0.6330
3177.2.0.64/27177.2.0.65 to 177.2.0.94177.2.0.9530
4177.2.0.96/27177.2.0.97 to 177.2.0.126177.2.0.12730
5177.2.0.128/27177.2.0.129 to 177.2.0.158177.2.0.15930
6177.2.0.160/27177.2.0.161 to 177.2.0.190177.2.0.19130
7177.2.0.192/27177.2.0.193 to 177.2.0.222177.2.0.22330
8177.2.0.224/27177.2.0.225 to 177.2.0.254177.2.0.25530
9177.2.1.0/27177.2.1.1 to 177.2.1.30177.2.1.3130
10177.2.1.32/27177.2.1.33 to 177.2.1.62177.2.1.6330
11177.2.1.64/27177.2.1.65 to 177.2.1.94177.2.1.9530
12177.2.1.96/27177.2.1.97 to 177.2.1.126177.2.1.12730
13177.2.1.128/27177.2.1.129 to 177.2.1.158177.2.1.15930
14177.2.1.160/27177.2.1.161 to 177.2.1.190177.2.1.19130
15177.2.1.192/27177.2.1.193 to 177.2.1.222177.2.1.22330
16177.2.1.224/27177.2.1.225 to 177.2.1.254177.2.1.25530
17177.2.2.0/27177.2.2.1 to 177.2.2.30177.2.2.3130
18177.2.2.32/27177.2.2.33 to 177.2.2.62177.2.2.6330
19177.2.2.64/27177.2.2.65 to 177.2.2.94177.2.2.9530
20177.2.2.96/27177.2.2.97 to 177.2.2.126177.2.2.12730
21177.2.2.128/27177.2.2.129 to 177.2.2.158177.2.2.15930
22177.2.2.160/27177.2.2.161 to 177.2.2.190177.2.2.19130
23177.2.2.192/27177.2.2.193 to 177.2.2.222177.2.2.22330
24177.2.2.224/27177.2.2.225 to 177.2.2.254177.2.2.25530
25177.2.3.0/27177.2.3.1 to 177.2.3.30177.2.3.3130
26177.2.3.32/27177.2.3.33 to 177.2.3.62177.2.3.6330
27177.2.3.64/27177.2.3.65 to 177.2.3.94177.2.3.9530
28177.2.3.96/27177.2.3.97 to 177.2.3.126177.2.3.12730
29177.2.3.128/27177.2.3.129 to 177.2.3.158177.2.3.15930
30177.2.3.160/27177.2.3.161 to 177.2.3.190177.2.3.19130
31177.2.3.192/27177.2.3.193 to 177.2.3.222177.2.3.22330
32177.2.3.224/27177.2.3.225 to 177.2.3.254177.2.3.25530
33177.2.4.0/27177.2.4.1 to 177.2.4.30177.2.4.3130
34177.2.4.32/27177.2.4.33 to 177.2.4.62177.2.4.6330
35177.2.4.64/27177.2.4.65 to 177.2.4.94177.2.4.9530
36177.2.4.96/27177.2.4.97 to 177.2.4.126177.2.4.12730
37177.2.4.128/27177.2.4.129 to 177.2.4.158177.2.4.15930
38177.2.4.160/27177.2.4.161 to 177.2.4.190177.2.4.19130
39177.2.4.192/27177.2.4.193 to 177.2.4.222177.2.4.22330
40177.2.4.224/27177.2.4.225 to 177.2.4.254177.2.4.25530
41177.2.5.0/27177.2.5.1 to 177.2.5.30177.2.5.3130
42177.2.5.32/27177.2.5.33 to 177.2.5.62177.2.5.6330
43177.2.5.64/27177.2.5.65 to 177.2.5.94177.2.5.9530
44177.2.5.96/27177.2.5.97 to 177.2.5.126177.2.5.12730
45177.2.5.128/27177.2.5.129 to 177.2.5.158177.2.5.15930
46177.2.5.160/27177.2.5.161 to 177.2.5.190177.2.5.19130
47177.2.5.192/27177.2.5.193 to 177.2.5.222177.2.5.22330
48177.2.5.224/27177.2.5.225 to 177.2.5.254177.2.5.25530
49177.2.6.0/27177.2.6.1 to 177.2.6.30177.2.6.3130
50177.2.6.32/27177.2.6.33 to 177.2.6.62177.2.6.6330
51177.2.6.64/27177.2.6.65 to 177.2.6.94177.2.6.9530
52177.2.6.96/27177.2.6.97 to 177.2.6.126177.2.6.12730
53177.2.6.128/27177.2.6.129 to 177.2.6.158177.2.6.15930
54177.2.6.160/27177.2.6.161 to 177.2.6.190177.2.6.19130
55177.2.6.192/27177.2.6.193 to 177.2.6.222177.2.6.22330
56177.2.6.224/27177.2.6.225 to 177.2.6.254177.2.6.25530
57177.2.7.0/27177.2.7.1 to 177.2.7.30177.2.7.3130
58177.2.7.32/27177.2.7.33 to 177.2.7.62177.2.7.6330
59177.2.7.64/27177.2.7.65 to 177.2.7.94177.2.7.9530
60177.2.7.96/27177.2.7.97 to 177.2.7.126177.2.7.12730
61177.2.7.128/27177.2.7.129 to 177.2.7.158177.2.7.15930
62177.2.7.160/27177.2.7.161 to 177.2.7.190177.2.7.19130
63177.2.7.192/27177.2.7.193 to 177.2.7.222177.2.7.22330
64177.2.7.224/27177.2.7.225 to 177.2.7.254177.2.7.25530
65177.2.8.0/27177.2.8.1 to 177.2.8.30177.2.8.3130
66177.2.8.32/27177.2.8.33 to 177.2.8.62177.2.8.6330
67177.2.8.64/27177.2.8.65 to 177.2.8.94177.2.8.9530
68177.2.8.96/27177.2.8.97 to 177.2.8.126177.2.8.12730
69177.2.8.128/27177.2.8.129 to 177.2.8.158177.2.8.15930
70177.2.8.160/27177.2.8.161 to 177.2.8.190177.2.8.19130
71177.2.8.192/27177.2.8.193 to 177.2.8.222177.2.8.22330
72177.2.8.224/27177.2.8.225 to 177.2.8.254177.2.8.25530
73177.2.9.0/27177.2.9.1 to 177.2.9.30177.2.9.3130
74177.2.9.32/27177.2.9.33 to 177.2.9.62177.2.9.6330
75177.2.9.64/27177.2.9.65 to 177.2.9.94177.2.9.9530
76177.2.9.96/27177.2.9.97 to 177.2.9.126177.2.9.12730
77177.2.9.128/27177.2.9.129 to 177.2.9.158177.2.9.15930
78177.2.9.160/27177.2.9.161 to 177.2.9.190177.2.9.19130
79177.2.9.192/27177.2.9.193 to 177.2.9.222177.2.9.22330
80177.2.9.224/27177.2.9.225 to 177.2.9.254177.2.9.25530
81177.2.10.0/27177.2.10.1 to 177.2.10.30177.2.10.3130
82177.2.10.32/27177.2.10.33 to 177.2.10.62177.2.10.6330
83177.2.10.64/27177.2.10.65 to 177.2.10.94177.2.10.9530
84177.2.10.96/27177.2.10.97 to 177.2.10.126177.2.10.12730
85177.2.10.128/27177.2.10.129 to 177.2.10.158177.2.10.15930
86177.2.10.160/27177.2.10.161 to 177.2.10.190177.2.10.19130
87177.2.10.192/27177.2.10.193 to 177.2.10.222177.2.10.22330
88177.2.10.224/27177.2.10.225 to 177.2.10.254177.2.10.25530
89177.2.11.0/27177.2.11.1 to 177.2.11.30177.2.11.3130
90177.2.11.32/27177.2.11.33 to 177.2.11.62177.2.11.6330
91177.2.11.64/27177.2.11.65 to 177.2.11.94177.2.11.9530
92177.2.11.96/27177.2.11.97 to 177.2.11.126177.2.11.12730
93177.2.11.128/27177.2.11.129 to 177.2.11.158177.2.11.15930
94177.2.11.160/27177.2.11.161 to 177.2.11.190177.2.11.19130
95177.2.11.192/27177.2.11.193 to 177.2.11.222177.2.11.22330
96177.2.11.224/27177.2.11.225 to 177.2.11.254177.2.11.25530
97177.2.12.0/27177.2.12.1 to 177.2.12.30177.2.12.3130
98177.2.12.32/27177.2.12.33 to 177.2.12.62177.2.12.6330
99177.2.12.64/27177.2.12.65 to 177.2.12.94177.2.12.9530
100177.2.12.96/27177.2.12.97 to 177.2.12.126177.2.12.12730
101177.2.12.128/27177.2.12.129 to 177.2.12.158177.2.12.15930
102177.2.12.160/27177.2.12.161 to 177.2.12.190177.2.12.19130
103177.2.12.192/27177.2.12.193 to 177.2.12.222177.2.12.22330
104177.2.12.224/27177.2.12.225 to 177.2.12.254177.2.12.25530
105177.2.13.0/27177.2.13.1 to 177.2.13.30177.2.13.3130
106177.2.13.32/27177.2.13.33 to 177.2.13.62177.2.13.6330
107177.2.13.64/27177.2.13.65 to 177.2.13.94177.2.13.9530
108177.2.13.96/27177.2.13.97 to 177.2.13.126177.2.13.12730
109177.2.13.128/27177.2.13.129 to 177.2.13.158177.2.13.15930
110177.2.13.160/27177.2.13.161 to 177.2.13.190177.2.13.19130
111177.2.13.192/27177.2.13.193 to 177.2.13.222177.2.13.22330
112177.2.13.224/27177.2.13.225 to 177.2.13.254177.2.13.25530
113177.2.14.0/27177.2.14.1 to 177.2.14.30177.2.14.3130
114177.2.14.32/27177.2.14.33 to 177.2.14.62177.2.14.6330
115177.2.14.64/27177.2.14.65 to 177.2.14.94177.2.14.9530
116177.2.14.96/27177.2.14.97 to 177.2.14.126177.2.14.12730
117177.2.14.128/27177.2.14.129 to 177.2.14.158177.2.14.15930
118177.2.14.160/27177.2.14.161 to 177.2.14.190177.2.14.19130
119177.2.14.192/27177.2.14.193 to 177.2.14.222177.2.14.22330
120177.2.14.224/27177.2.14.225 to 177.2.14.254177.2.14.25530
121177.2.15.0/27177.2.15.1 to 177.2.15.30177.2.15.3130
122177.2.15.32/27177.2.15.33 to 177.2.15.62177.2.15.6330
123177.2.15.64/27177.2.15.65 to 177.2.15.94177.2.15.9530
124177.2.15.96/27177.2.15.97 to 177.2.15.126177.2.15.12730
125177.2.15.128/27177.2.15.129 to 177.2.15.158177.2.15.15930
126177.2.15.160/27177.2.15.161 to 177.2.15.190177.2.15.19130
127177.2.15.192/27177.2.15.193 to 177.2.15.222177.2.15.22330
128177.2.15.224/27177.2.15.225 to 177.2.15.254177.2.15.25530
129177.2.16.0/27177.2.16.1 to 177.2.16.30177.2.16.3130
130177.2.16.32/27177.2.16.33 to 177.2.16.62177.2.16.6330
131177.2.16.64/27177.2.16.65 to 177.2.16.94177.2.16.9530
132177.2.16.96/27177.2.16.97 to 177.2.16.126177.2.16.12730
133177.2.16.128/27177.2.16.129 to 177.2.16.158177.2.16.15930
134177.2.16.160/27177.2.16.161 to 177.2.16.190177.2.16.19130
135177.2.16.192/27177.2.16.193 to 177.2.16.222177.2.16.22330
136177.2.16.224/27177.2.16.225 to 177.2.16.254177.2.16.25530
137177.2.17.0/27177.2.17.1 to 177.2.17.30177.2.17.3130
138177.2.17.32/27177.2.17.33 to 177.2.17.62177.2.17.6330
139177.2.17.64/27177.2.17.65 to 177.2.17.94177.2.17.9530
140177.2.17.96/27177.2.17.97 to 177.2.17.126177.2.17.12730
141177.2.17.128/27177.2.17.129 to 177.2.17.158177.2.17.15930
142177.2.17.160/27177.2.17.161 to 177.2.17.190177.2.17.19130
143177.2.17.192/27177.2.17.193 to 177.2.17.222177.2.17.22330
144177.2.17.224/27177.2.17.225 to 177.2.17.254177.2.17.25530
145177.2.18.0/27177.2.18.1 to 177.2.18.30177.2.18.3130
146177.2.18.32/27177.2.18.33 to 177.2.18.62177.2.18.6330
147177.2.18.64/27177.2.18.65 to 177.2.18.94177.2.18.9530
148177.2.18.96/27177.2.18.97 to 177.2.18.126177.2.18.12730
149177.2.18.128/27177.2.18.129 to 177.2.18.158177.2.18.15930
150177.2.18.160/27177.2.18.161 to 177.2.18.190177.2.18.19130
151177.2.18.192/27177.2.18.193 to 177.2.18.222177.2.18.22330
152177.2.18.224/27177.2.18.225 to 177.2.18.254177.2.18.25530
153177.2.19.0/27177.2.19.1 to 177.2.19.30177.2.19.3130
154177.2.19.32/27177.2.19.33 to 177.2.19.62177.2.19.6330
155177.2.19.64/27177.2.19.65 to 177.2.19.94177.2.19.9530
156177.2.19.96/27177.2.19.97 to 177.2.19.126177.2.19.12730
157177.2.19.128/27177.2.19.129 to 177.2.19.158177.2.19.15930
158177.2.19.160/27177.2.19.161 to 177.2.19.190177.2.19.19130
159177.2.19.192/27177.2.19.193 to 177.2.19.222177.2.19.22330
160177.2.19.224/27177.2.19.225 to 177.2.19.254177.2.19.25530
161177.2.20.0/27177.2.20.1 to 177.2.20.30177.2.20.3130
162177.2.20.32/27177.2.20.33 to 177.2.20.62177.2.20.6330
163177.2.20.64/27177.2.20.65 to 177.2.20.94177.2.20.9530
164177.2.20.96/27177.2.20.97 to 177.2.20.126177.2.20.12730
165177.2.20.128/27177.2.20.129 to 177.2.20.158177.2.20.15930
166177.2.20.160/27177.2.20.161 to 177.2.20.190177.2.20.19130
167177.2.20.192/27177.2.20.193 to 177.2.20.222177.2.20.22330
168177.2.20.224/27177.2.20.225 to 177.2.20.254177.2.20.25530
169177.2.21.0/27177.2.21.1 to 177.2.21.30177.2.21.3130
170177.2.21.32/27177.2.21.33 to 177.2.21.62177.2.21.6330
171177.2.21.64/27177.2.21.65 to 177.2.21.94177.2.21.9530
172177.2.21.96/27177.2.21.97 to 177.2.21.126177.2.21.12730
173177.2.21.128/27177.2.21.129 to 177.2.21.158177.2.21.15930
174177.2.21.160/27177.2.21.161 to 177.2.21.190177.2.21.19130
175177.2.21.192/27177.2.21.193 to 177.2.21.222177.2.21.22330
176177.2.21.224/27177.2.21.225 to 177.2.21.254177.2.21.25530
177177.2.22.0/27177.2.22.1 to 177.2.22.30177.2.22.3130
178177.2.22.32/27177.2.22.33 to 177.2.22.62177.2.22.6330
179177.2.22.64/27177.2.22.65 to 177.2.22.94177.2.22.9530
180177.2.22.96/27177.2.22.97 to 177.2.22.126177.2.22.12730
181177.2.22.128/27177.2.22.129 to 177.2.22.158177.2.22.15930
182177.2.22.160/27177.2.22.161 to 177.2.22.190177.2.22.19130
183177.2.22.192/27177.2.22.193 to 177.2.22.222177.2.22.22330
184177.2.22.224/27177.2.22.225 to 177.2.22.254177.2.22.25530
185177.2.23.0/27177.2.23.1 to 177.2.23.30177.2.23.3130
186177.2.23.32/27177.2.23.33 to 177.2.23.62177.2.23.6330
187177.2.23.64/27177.2.23.65 to 177.2.23.94177.2.23.9530
188177.2.23.96/27177.2.23.97 to 177.2.23.126177.2.23.12730
189177.2.23.128/27177.2.23.129 to 177.2.23.158177.2.23.15930
190177.2.23.160/27177.2.23.161 to 177.2.23.190177.2.23.19130
191177.2.23.192/27177.2.23.193 to 177.2.23.222177.2.23.22330
192177.2.23.224/27177.2.23.225 to 177.2.23.254177.2.23.25530
193177.2.24.0/27177.2.24.1 to 177.2.24.30177.2.24.3130
194177.2.24.32/27177.2.24.33 to 177.2.24.62177.2.24.6330
195177.2.24.64/27177.2.24.65 to 177.2.24.94177.2.24.9530
196177.2.24.96/27177.2.24.97 to 177.2.24.126177.2.24.12730
197177.2.24.128/27177.2.24.129 to 177.2.24.158177.2.24.15930
198177.2.24.160/27177.2.24.161 to 177.2.24.190177.2.24.19130
199177.2.24.192/27177.2.24.193 to 177.2.24.222177.2.24.22330
200177.2.24.224/27177.2.24.225 to 177.2.24.254177.2.24.25530
201177.2.25.0/27177.2.25.1 to 177.2.25.30177.2.25.3130
202177.2.25.32/27177.2.25.33 to 177.2.25.62177.2.25.6330
203177.2.25.64/27177.2.25.65 to 177.2.25.94177.2.25.9530
204177.2.25.96/27177.2.25.97 to 177.2.25.126177.2.25.12730
205177.2.25.128/27177.2.25.129 to 177.2.25.158177.2.25.15930
206177.2.25.160/27177.2.25.161 to 177.2.25.190177.2.25.19130
207177.2.25.192/27177.2.25.193 to 177.2.25.222177.2.25.22330
208177.2.25.224/27177.2.25.225 to 177.2.25.254177.2.25.25530
209177.2.26.0/27177.2.26.1 to 177.2.26.30177.2.26.3130
210177.2.26.32/27177.2.26.33 to 177.2.26.62177.2.26.6330
211177.2.26.64/27177.2.26.65 to 177.2.26.94177.2.26.9530
212177.2.26.96/27177.2.26.97 to 177.2.26.126177.2.26.12730
213177.2.26.128/27177.2.26.129 to 177.2.26.158177.2.26.15930
214177.2.26.160/27177.2.26.161 to 177.2.26.190177.2.26.19130
215177.2.26.192/27177.2.26.193 to 177.2.26.222177.2.26.22330
216177.2.26.224/27177.2.26.225 to 177.2.26.254177.2.26.25530
217177.2.27.0/27177.2.27.1 to 177.2.27.30177.2.27.3130
218177.2.27.32/27177.2.27.33 to 177.2.27.62177.2.27.6330
219177.2.27.64/27177.2.27.65 to 177.2.27.94177.2.27.9530
220177.2.27.96/27177.2.27.97 to 177.2.27.126177.2.27.12730
221177.2.27.128/27177.2.27.129 to 177.2.27.158177.2.27.15930
222177.2.27.160/27177.2.27.161 to 177.2.27.190177.2.27.19130
223177.2.27.192/27177.2.27.193 to 177.2.27.222177.2.27.22330
224177.2.27.224/27177.2.27.225 to 177.2.27.254177.2.27.25530
225177.2.28.0/27177.2.28.1 to 177.2.28.30177.2.28.3130
226177.2.28.32/27177.2.28.33 to 177.2.28.62177.2.28.6330
227177.2.28.64/27177.2.28.65 to 177.2.28.94177.2.28.9530
228177.2.28.96/27177.2.28.97 to 177.2.28.126177.2.28.12730
229177.2.28.128/27177.2.28.129 to 177.2.28.158177.2.28.15930
230177.2.28.160/27177.2.28.161 to 177.2.28.190177.2.28.19130
231177.2.28.192/27177.2.28.193 to 177.2.28.222177.2.28.22330
232177.2.28.224/27177.2.28.225 to 177.2.28.254177.2.28.25530
233177.2.29.0/27177.2.29.1 to 177.2.29.30177.2.29.3130
234177.2.29.32/27177.2.29.33 to 177.2.29.62177.2.29.6330
235177.2.29.64/27177.2.29.65 to 177.2.29.94177.2.29.9530
236177.2.29.96/27177.2.29.97 to 177.2.29.126177.2.29.12730
237177.2.29.128/27177.2.29.129 to 177.2.29.158177.2.29.15930
238177.2.29.160/27177.2.29.161 to 177.2.29.190177.2.29.19130
239177.2.29.192/27177.2.29.193 to 177.2.29.222177.2.29.22330
240177.2.29.224/27177.2.29.225 to 177.2.29.254177.2.29.25530
241177.2.30.0/27177.2.30.1 to 177.2.30.30177.2.30.3130
242177.2.30.32/27177.2.30.33 to 177.2.30.62177.2.30.6330
243177.2.30.64/27177.2.30.65 to 177.2.30.94177.2.30.9530
244177.2.30.96/27177.2.30.97 to 177.2.30.126177.2.30.12730
245177.2.30.128/27177.2.30.129 to 177.2.30.158177.2.30.15930
246177.2.30.160/27177.2.30.161 to 177.2.30.190177.2.30.19130
247177.2.30.192/27177.2.30.193 to 177.2.30.222177.2.30.22330
248177.2.30.224/27177.2.30.225 to 177.2.30.254177.2.30.25530
249177.2.31.0/27177.2.31.1 to 177.2.31.30177.2.31.3130
250177.2.31.32/27177.2.31.33 to 177.2.31.62177.2.31.6330
251177.2.31.64/27177.2.31.65 to 177.2.31.94177.2.31.9530
252177.2.31.96/27177.2.31.97 to 177.2.31.126177.2.31.12730
253177.2.31.128/27177.2.31.129 to 177.2.31.158177.2.31.15930
254177.2.31.160/27177.2.31.161 to 177.2.31.190177.2.31.19130
255177.2.31.192/27177.2.31.193 to 177.2.31.222177.2.31.22330
256177.2.31.224/27177.2.31.225 to 177.2.31.254177.2.31.25530

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.