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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.

Network212.45.0.0/17
Usable hosts32,766
Subnet mask255.255.128.0
Addresses32,768
Network address
212.45.0.0
Broadcast address
212.45.127.255
First usable
212.45.0.1
Last usable
212.45.127.254
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
C (default /24)
As numbers
Hex D42D0000 · Integer 3559718912 to 3559751679
Reverse DNS zones
0.45.212.in-addr.arpa
1.45.212.in-addr.arpa
2.45.212.in-addr.arpa
3.45.212.in-addr.arpa
4.45.212.in-addr.arpa
5.45.212.in-addr.arpa
6.45.212.in-addr.arpa
7.45.212.in-addr.arpa
8.45.212.in-addr.arpa
9.45.212.in-addr.arpa
10.45.212.in-addr.arpa
11.45.212.in-addr.arpa
12.45.212.in-addr.arpa
13.45.212.in-addr.arpa
14.45.212.in-addr.arpa
15.45.212.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
Address11010100.00101101.00000000.00000000212.45.0.0
Subnet mask11111111.11111111.10000000.00000000255.255.128.0
Network11010100.00101101.00000000.00000000212.45.0.0
Broadcast11010100.00101101.01111111.11111111212.45.127.255
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)

212.45.0.0/17 makes 2,048 subnets of /28; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1212.45.0.0/28212.45.0.1 to 212.45.0.14212.45.0.1514
2212.45.0.16/28212.45.0.17 to 212.45.0.30212.45.0.3114
3212.45.0.32/28212.45.0.33 to 212.45.0.46212.45.0.4714
4212.45.0.48/28212.45.0.49 to 212.45.0.62212.45.0.6314
5212.45.0.64/28212.45.0.65 to 212.45.0.78212.45.0.7914
6212.45.0.80/28212.45.0.81 to 212.45.0.94212.45.0.9514
7212.45.0.96/28212.45.0.97 to 212.45.0.110212.45.0.11114
8212.45.0.112/28212.45.0.113 to 212.45.0.126212.45.0.12714
9212.45.0.128/28212.45.0.129 to 212.45.0.142212.45.0.14314
10212.45.0.144/28212.45.0.145 to 212.45.0.158212.45.0.15914
11212.45.0.160/28212.45.0.161 to 212.45.0.174212.45.0.17514
12212.45.0.176/28212.45.0.177 to 212.45.0.190212.45.0.19114
13212.45.0.192/28212.45.0.193 to 212.45.0.206212.45.0.20714
14212.45.0.208/28212.45.0.209 to 212.45.0.222212.45.0.22314
15212.45.0.224/28212.45.0.225 to 212.45.0.238212.45.0.23914
16212.45.0.240/28212.45.0.241 to 212.45.0.254212.45.0.25514
17212.45.1.0/28212.45.1.1 to 212.45.1.14212.45.1.1514
18212.45.1.16/28212.45.1.17 to 212.45.1.30212.45.1.3114
19212.45.1.32/28212.45.1.33 to 212.45.1.46212.45.1.4714
20212.45.1.48/28212.45.1.49 to 212.45.1.62212.45.1.6314
21212.45.1.64/28212.45.1.65 to 212.45.1.78212.45.1.7914
22212.45.1.80/28212.45.1.81 to 212.45.1.94212.45.1.9514
23212.45.1.96/28212.45.1.97 to 212.45.1.110212.45.1.11114
24212.45.1.112/28212.45.1.113 to 212.45.1.126212.45.1.12714
25212.45.1.128/28212.45.1.129 to 212.45.1.142212.45.1.14314
26212.45.1.144/28212.45.1.145 to 212.45.1.158212.45.1.15914
27212.45.1.160/28212.45.1.161 to 212.45.1.174212.45.1.17514
28212.45.1.176/28212.45.1.177 to 212.45.1.190212.45.1.19114
29212.45.1.192/28212.45.1.193 to 212.45.1.206212.45.1.20714
30212.45.1.208/28212.45.1.209 to 212.45.1.222212.45.1.22314
31212.45.1.224/28212.45.1.225 to 212.45.1.238212.45.1.23914
32212.45.1.240/28212.45.1.241 to 212.45.1.254212.45.1.25514
33212.45.2.0/28212.45.2.1 to 212.45.2.14212.45.2.1514
34212.45.2.16/28212.45.2.17 to 212.45.2.30212.45.2.3114
35212.45.2.32/28212.45.2.33 to 212.45.2.46212.45.2.4714
36212.45.2.48/28212.45.2.49 to 212.45.2.62212.45.2.6314
37212.45.2.64/28212.45.2.65 to 212.45.2.78212.45.2.7914
38212.45.2.80/28212.45.2.81 to 212.45.2.94212.45.2.9514
39212.45.2.96/28212.45.2.97 to 212.45.2.110212.45.2.11114
40212.45.2.112/28212.45.2.113 to 212.45.2.126212.45.2.12714
41212.45.2.128/28212.45.2.129 to 212.45.2.142212.45.2.14314
42212.45.2.144/28212.45.2.145 to 212.45.2.158212.45.2.15914
43212.45.2.160/28212.45.2.161 to 212.45.2.174212.45.2.17514
44212.45.2.176/28212.45.2.177 to 212.45.2.190212.45.2.19114
45212.45.2.192/28212.45.2.193 to 212.45.2.206212.45.2.20714
46212.45.2.208/28212.45.2.209 to 212.45.2.222212.45.2.22314
47212.45.2.224/28212.45.2.225 to 212.45.2.238212.45.2.23914
48212.45.2.240/28212.45.2.241 to 212.45.2.254212.45.2.25514
49212.45.3.0/28212.45.3.1 to 212.45.3.14212.45.3.1514
50212.45.3.16/28212.45.3.17 to 212.45.3.30212.45.3.3114
51212.45.3.32/28212.45.3.33 to 212.45.3.46212.45.3.4714
52212.45.3.48/28212.45.3.49 to 212.45.3.62212.45.3.6314
53212.45.3.64/28212.45.3.65 to 212.45.3.78212.45.3.7914
54212.45.3.80/28212.45.3.81 to 212.45.3.94212.45.3.9514
55212.45.3.96/28212.45.3.97 to 212.45.3.110212.45.3.11114
56212.45.3.112/28212.45.3.113 to 212.45.3.126212.45.3.12714
57212.45.3.128/28212.45.3.129 to 212.45.3.142212.45.3.14314
58212.45.3.144/28212.45.3.145 to 212.45.3.158212.45.3.15914
59212.45.3.160/28212.45.3.161 to 212.45.3.174212.45.3.17514
60212.45.3.176/28212.45.3.177 to 212.45.3.190212.45.3.19114
61212.45.3.192/28212.45.3.193 to 212.45.3.206212.45.3.20714
62212.45.3.208/28212.45.3.209 to 212.45.3.222212.45.3.22314
63212.45.3.224/28212.45.3.225 to 212.45.3.238212.45.3.23914
64212.45.3.240/28212.45.3.241 to 212.45.3.254212.45.3.25514
65212.45.4.0/28212.45.4.1 to 212.45.4.14212.45.4.1514
66212.45.4.16/28212.45.4.17 to 212.45.4.30212.45.4.3114
67212.45.4.32/28212.45.4.33 to 212.45.4.46212.45.4.4714
68212.45.4.48/28212.45.4.49 to 212.45.4.62212.45.4.6314
69212.45.4.64/28212.45.4.65 to 212.45.4.78212.45.4.7914
70212.45.4.80/28212.45.4.81 to 212.45.4.94212.45.4.9514
71212.45.4.96/28212.45.4.97 to 212.45.4.110212.45.4.11114
72212.45.4.112/28212.45.4.113 to 212.45.4.126212.45.4.12714
73212.45.4.128/28212.45.4.129 to 212.45.4.142212.45.4.14314
74212.45.4.144/28212.45.4.145 to 212.45.4.158212.45.4.15914
75212.45.4.160/28212.45.4.161 to 212.45.4.174212.45.4.17514
76212.45.4.176/28212.45.4.177 to 212.45.4.190212.45.4.19114
77212.45.4.192/28212.45.4.193 to 212.45.4.206212.45.4.20714
78212.45.4.208/28212.45.4.209 to 212.45.4.222212.45.4.22314
79212.45.4.224/28212.45.4.225 to 212.45.4.238212.45.4.23914
80212.45.4.240/28212.45.4.241 to 212.45.4.254212.45.4.25514
81212.45.5.0/28212.45.5.1 to 212.45.5.14212.45.5.1514
82212.45.5.16/28212.45.5.17 to 212.45.5.30212.45.5.3114
83212.45.5.32/28212.45.5.33 to 212.45.5.46212.45.5.4714
84212.45.5.48/28212.45.5.49 to 212.45.5.62212.45.5.6314
85212.45.5.64/28212.45.5.65 to 212.45.5.78212.45.5.7914
86212.45.5.80/28212.45.5.81 to 212.45.5.94212.45.5.9514
87212.45.5.96/28212.45.5.97 to 212.45.5.110212.45.5.11114
88212.45.5.112/28212.45.5.113 to 212.45.5.126212.45.5.12714
89212.45.5.128/28212.45.5.129 to 212.45.5.142212.45.5.14314
90212.45.5.144/28212.45.5.145 to 212.45.5.158212.45.5.15914
91212.45.5.160/28212.45.5.161 to 212.45.5.174212.45.5.17514
92212.45.5.176/28212.45.5.177 to 212.45.5.190212.45.5.19114
93212.45.5.192/28212.45.5.193 to 212.45.5.206212.45.5.20714
94212.45.5.208/28212.45.5.209 to 212.45.5.222212.45.5.22314
95212.45.5.224/28212.45.5.225 to 212.45.5.238212.45.5.23914
96212.45.5.240/28212.45.5.241 to 212.45.5.254212.45.5.25514
97212.45.6.0/28212.45.6.1 to 212.45.6.14212.45.6.1514
98212.45.6.16/28212.45.6.17 to 212.45.6.30212.45.6.3114
99212.45.6.32/28212.45.6.33 to 212.45.6.46212.45.6.4714
100212.45.6.48/28212.45.6.49 to 212.45.6.62212.45.6.6314
101212.45.6.64/28212.45.6.65 to 212.45.6.78212.45.6.7914
102212.45.6.80/28212.45.6.81 to 212.45.6.94212.45.6.9514
103212.45.6.96/28212.45.6.97 to 212.45.6.110212.45.6.11114
104212.45.6.112/28212.45.6.113 to 212.45.6.126212.45.6.12714
105212.45.6.128/28212.45.6.129 to 212.45.6.142212.45.6.14314
106212.45.6.144/28212.45.6.145 to 212.45.6.158212.45.6.15914
107212.45.6.160/28212.45.6.161 to 212.45.6.174212.45.6.17514
108212.45.6.176/28212.45.6.177 to 212.45.6.190212.45.6.19114
109212.45.6.192/28212.45.6.193 to 212.45.6.206212.45.6.20714
110212.45.6.208/28212.45.6.209 to 212.45.6.222212.45.6.22314
111212.45.6.224/28212.45.6.225 to 212.45.6.238212.45.6.23914
112212.45.6.240/28212.45.6.241 to 212.45.6.254212.45.6.25514
113212.45.7.0/28212.45.7.1 to 212.45.7.14212.45.7.1514
114212.45.7.16/28212.45.7.17 to 212.45.7.30212.45.7.3114
115212.45.7.32/28212.45.7.33 to 212.45.7.46212.45.7.4714
116212.45.7.48/28212.45.7.49 to 212.45.7.62212.45.7.6314
117212.45.7.64/28212.45.7.65 to 212.45.7.78212.45.7.7914
118212.45.7.80/28212.45.7.81 to 212.45.7.94212.45.7.9514
119212.45.7.96/28212.45.7.97 to 212.45.7.110212.45.7.11114
120212.45.7.112/28212.45.7.113 to 212.45.7.126212.45.7.12714
121212.45.7.128/28212.45.7.129 to 212.45.7.142212.45.7.14314
122212.45.7.144/28212.45.7.145 to 212.45.7.158212.45.7.15914
123212.45.7.160/28212.45.7.161 to 212.45.7.174212.45.7.17514
124212.45.7.176/28212.45.7.177 to 212.45.7.190212.45.7.19114
125212.45.7.192/28212.45.7.193 to 212.45.7.206212.45.7.20714
126212.45.7.208/28212.45.7.209 to 212.45.7.222212.45.7.22314
127212.45.7.224/28212.45.7.225 to 212.45.7.238212.45.7.23914
128212.45.7.240/28212.45.7.241 to 212.45.7.254212.45.7.25514
129212.45.8.0/28212.45.8.1 to 212.45.8.14212.45.8.1514
130212.45.8.16/28212.45.8.17 to 212.45.8.30212.45.8.3114
131212.45.8.32/28212.45.8.33 to 212.45.8.46212.45.8.4714
132212.45.8.48/28212.45.8.49 to 212.45.8.62212.45.8.6314
133212.45.8.64/28212.45.8.65 to 212.45.8.78212.45.8.7914
134212.45.8.80/28212.45.8.81 to 212.45.8.94212.45.8.9514
135212.45.8.96/28212.45.8.97 to 212.45.8.110212.45.8.11114
136212.45.8.112/28212.45.8.113 to 212.45.8.126212.45.8.12714
137212.45.8.128/28212.45.8.129 to 212.45.8.142212.45.8.14314
138212.45.8.144/28212.45.8.145 to 212.45.8.158212.45.8.15914
139212.45.8.160/28212.45.8.161 to 212.45.8.174212.45.8.17514
140212.45.8.176/28212.45.8.177 to 212.45.8.190212.45.8.19114
141212.45.8.192/28212.45.8.193 to 212.45.8.206212.45.8.20714
142212.45.8.208/28212.45.8.209 to 212.45.8.222212.45.8.22314
143212.45.8.224/28212.45.8.225 to 212.45.8.238212.45.8.23914
144212.45.8.240/28212.45.8.241 to 212.45.8.254212.45.8.25514
145212.45.9.0/28212.45.9.1 to 212.45.9.14212.45.9.1514
146212.45.9.16/28212.45.9.17 to 212.45.9.30212.45.9.3114
147212.45.9.32/28212.45.9.33 to 212.45.9.46212.45.9.4714
148212.45.9.48/28212.45.9.49 to 212.45.9.62212.45.9.6314
149212.45.9.64/28212.45.9.65 to 212.45.9.78212.45.9.7914
150212.45.9.80/28212.45.9.81 to 212.45.9.94212.45.9.9514
151212.45.9.96/28212.45.9.97 to 212.45.9.110212.45.9.11114
152212.45.9.112/28212.45.9.113 to 212.45.9.126212.45.9.12714
153212.45.9.128/28212.45.9.129 to 212.45.9.142212.45.9.14314
154212.45.9.144/28212.45.9.145 to 212.45.9.158212.45.9.15914
155212.45.9.160/28212.45.9.161 to 212.45.9.174212.45.9.17514
156212.45.9.176/28212.45.9.177 to 212.45.9.190212.45.9.19114
157212.45.9.192/28212.45.9.193 to 212.45.9.206212.45.9.20714
158212.45.9.208/28212.45.9.209 to 212.45.9.222212.45.9.22314
159212.45.9.224/28212.45.9.225 to 212.45.9.238212.45.9.23914
160212.45.9.240/28212.45.9.241 to 212.45.9.254212.45.9.25514
161212.45.10.0/28212.45.10.1 to 212.45.10.14212.45.10.1514
162212.45.10.16/28212.45.10.17 to 212.45.10.30212.45.10.3114
163212.45.10.32/28212.45.10.33 to 212.45.10.46212.45.10.4714
164212.45.10.48/28212.45.10.49 to 212.45.10.62212.45.10.6314
165212.45.10.64/28212.45.10.65 to 212.45.10.78212.45.10.7914
166212.45.10.80/28212.45.10.81 to 212.45.10.94212.45.10.9514
167212.45.10.96/28212.45.10.97 to 212.45.10.110212.45.10.11114
168212.45.10.112/28212.45.10.113 to 212.45.10.126212.45.10.12714
169212.45.10.128/28212.45.10.129 to 212.45.10.142212.45.10.14314
170212.45.10.144/28212.45.10.145 to 212.45.10.158212.45.10.15914
171212.45.10.160/28212.45.10.161 to 212.45.10.174212.45.10.17514
172212.45.10.176/28212.45.10.177 to 212.45.10.190212.45.10.19114
173212.45.10.192/28212.45.10.193 to 212.45.10.206212.45.10.20714
174212.45.10.208/28212.45.10.209 to 212.45.10.222212.45.10.22314
175212.45.10.224/28212.45.10.225 to 212.45.10.238212.45.10.23914
176212.45.10.240/28212.45.10.241 to 212.45.10.254212.45.10.25514
177212.45.11.0/28212.45.11.1 to 212.45.11.14212.45.11.1514
178212.45.11.16/28212.45.11.17 to 212.45.11.30212.45.11.3114
179212.45.11.32/28212.45.11.33 to 212.45.11.46212.45.11.4714
180212.45.11.48/28212.45.11.49 to 212.45.11.62212.45.11.6314
181212.45.11.64/28212.45.11.65 to 212.45.11.78212.45.11.7914
182212.45.11.80/28212.45.11.81 to 212.45.11.94212.45.11.9514
183212.45.11.96/28212.45.11.97 to 212.45.11.110212.45.11.11114
184212.45.11.112/28212.45.11.113 to 212.45.11.126212.45.11.12714
185212.45.11.128/28212.45.11.129 to 212.45.11.142212.45.11.14314
186212.45.11.144/28212.45.11.145 to 212.45.11.158212.45.11.15914
187212.45.11.160/28212.45.11.161 to 212.45.11.174212.45.11.17514
188212.45.11.176/28212.45.11.177 to 212.45.11.190212.45.11.19114
189212.45.11.192/28212.45.11.193 to 212.45.11.206212.45.11.20714
190212.45.11.208/28212.45.11.209 to 212.45.11.222212.45.11.22314
191212.45.11.224/28212.45.11.225 to 212.45.11.238212.45.11.23914
192212.45.11.240/28212.45.11.241 to 212.45.11.254212.45.11.25514
193212.45.12.0/28212.45.12.1 to 212.45.12.14212.45.12.1514
194212.45.12.16/28212.45.12.17 to 212.45.12.30212.45.12.3114
195212.45.12.32/28212.45.12.33 to 212.45.12.46212.45.12.4714
196212.45.12.48/28212.45.12.49 to 212.45.12.62212.45.12.6314
197212.45.12.64/28212.45.12.65 to 212.45.12.78212.45.12.7914
198212.45.12.80/28212.45.12.81 to 212.45.12.94212.45.12.9514
199212.45.12.96/28212.45.12.97 to 212.45.12.110212.45.12.11114
200212.45.12.112/28212.45.12.113 to 212.45.12.126212.45.12.12714
201212.45.12.128/28212.45.12.129 to 212.45.12.142212.45.12.14314
202212.45.12.144/28212.45.12.145 to 212.45.12.158212.45.12.15914
203212.45.12.160/28212.45.12.161 to 212.45.12.174212.45.12.17514
204212.45.12.176/28212.45.12.177 to 212.45.12.190212.45.12.19114
205212.45.12.192/28212.45.12.193 to 212.45.12.206212.45.12.20714
206212.45.12.208/28212.45.12.209 to 212.45.12.222212.45.12.22314
207212.45.12.224/28212.45.12.225 to 212.45.12.238212.45.12.23914
208212.45.12.240/28212.45.12.241 to 212.45.12.254212.45.12.25514
209212.45.13.0/28212.45.13.1 to 212.45.13.14212.45.13.1514
210212.45.13.16/28212.45.13.17 to 212.45.13.30212.45.13.3114
211212.45.13.32/28212.45.13.33 to 212.45.13.46212.45.13.4714
212212.45.13.48/28212.45.13.49 to 212.45.13.62212.45.13.6314
213212.45.13.64/28212.45.13.65 to 212.45.13.78212.45.13.7914
214212.45.13.80/28212.45.13.81 to 212.45.13.94212.45.13.9514
215212.45.13.96/28212.45.13.97 to 212.45.13.110212.45.13.11114
216212.45.13.112/28212.45.13.113 to 212.45.13.126212.45.13.12714
217212.45.13.128/28212.45.13.129 to 212.45.13.142212.45.13.14314
218212.45.13.144/28212.45.13.145 to 212.45.13.158212.45.13.15914
219212.45.13.160/28212.45.13.161 to 212.45.13.174212.45.13.17514
220212.45.13.176/28212.45.13.177 to 212.45.13.190212.45.13.19114
221212.45.13.192/28212.45.13.193 to 212.45.13.206212.45.13.20714
222212.45.13.208/28212.45.13.209 to 212.45.13.222212.45.13.22314
223212.45.13.224/28212.45.13.225 to 212.45.13.238212.45.13.23914
224212.45.13.240/28212.45.13.241 to 212.45.13.254212.45.13.25514
225212.45.14.0/28212.45.14.1 to 212.45.14.14212.45.14.1514
226212.45.14.16/28212.45.14.17 to 212.45.14.30212.45.14.3114
227212.45.14.32/28212.45.14.33 to 212.45.14.46212.45.14.4714
228212.45.14.48/28212.45.14.49 to 212.45.14.62212.45.14.6314
229212.45.14.64/28212.45.14.65 to 212.45.14.78212.45.14.7914
230212.45.14.80/28212.45.14.81 to 212.45.14.94212.45.14.9514
231212.45.14.96/28212.45.14.97 to 212.45.14.110212.45.14.11114
232212.45.14.112/28212.45.14.113 to 212.45.14.126212.45.14.12714
233212.45.14.128/28212.45.14.129 to 212.45.14.142212.45.14.14314
234212.45.14.144/28212.45.14.145 to 212.45.14.158212.45.14.15914
235212.45.14.160/28212.45.14.161 to 212.45.14.174212.45.14.17514
236212.45.14.176/28212.45.14.177 to 212.45.14.190212.45.14.19114
237212.45.14.192/28212.45.14.193 to 212.45.14.206212.45.14.20714
238212.45.14.208/28212.45.14.209 to 212.45.14.222212.45.14.22314
239212.45.14.224/28212.45.14.225 to 212.45.14.238212.45.14.23914
240212.45.14.240/28212.45.14.241 to 212.45.14.254212.45.14.25514
241212.45.15.0/28212.45.15.1 to 212.45.15.14212.45.15.1514
242212.45.15.16/28212.45.15.17 to 212.45.15.30212.45.15.3114
243212.45.15.32/28212.45.15.33 to 212.45.15.46212.45.15.4714
244212.45.15.48/28212.45.15.49 to 212.45.15.62212.45.15.6314
245212.45.15.64/28212.45.15.65 to 212.45.15.78212.45.15.7914
246212.45.15.80/28212.45.15.81 to 212.45.15.94212.45.15.9514
247212.45.15.96/28212.45.15.97 to 212.45.15.110212.45.15.11114
248212.45.15.112/28212.45.15.113 to 212.45.15.126212.45.15.12714
249212.45.15.128/28212.45.15.129 to 212.45.15.142212.45.15.14314
250212.45.15.144/28212.45.15.145 to 212.45.15.158212.45.15.15914
251212.45.15.160/28212.45.15.161 to 212.45.15.174212.45.15.17514
252212.45.15.176/28212.45.15.177 to 212.45.15.190212.45.15.19114
253212.45.15.192/28212.45.15.193 to 212.45.15.206212.45.15.20714
254212.45.15.208/28212.45.15.209 to 212.45.15.222212.45.15.22314
255212.45.15.224/28212.45.15.225 to 212.45.15.238212.45.15.23914
256212.45.15.240/28212.45.15.241 to 212.45.15.254212.45.15.25514

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.