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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.

Network164.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
164.0.0.0
Broadcast address
164.255.255.255
First usable
164.0.0.1
Last usable
164.255.255.254
Usable hosts
16,777,214 (16,777,216 less the network and broadcast addresses)
Subnet mask
255.0.0.0
Wildcard mask
0.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/8
Type
Public public
Old class
B (default /16)
As numbers
Hex A4000000 · Integer 2751463424 to 2768240639
Reverse DNS zone
164.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10100100..00000000.00000000.00000000164.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network10100100..00000000.00000000.00000000164.0.0.0
Broadcast10100100..11111111.11111111.11111111164.255.255.255
Split into smaller subnets/19
/9 (2)/10 (4)/11 (8)/12 (16)/13 (32)/14 (64)/15 (128)/16 (256)/17 (512)/18 (1,024)/19 (2,048)/20 (4,096)

164.0.0.0/8 makes 2,048 subnets of /19; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1164.0.0.0/19164.0.0.1 to 164.0.31.254164.0.31.2558,190
2164.0.32.0/19164.0.32.1 to 164.0.63.254164.0.63.2558,190
3164.0.64.0/19164.0.64.1 to 164.0.95.254164.0.95.2558,190
4164.0.96.0/19164.0.96.1 to 164.0.127.254164.0.127.2558,190
5164.0.128.0/19164.0.128.1 to 164.0.159.254164.0.159.2558,190
6164.0.160.0/19164.0.160.1 to 164.0.191.254164.0.191.2558,190
7164.0.192.0/19164.0.192.1 to 164.0.223.254164.0.223.2558,190
8164.0.224.0/19164.0.224.1 to 164.0.255.254164.0.255.2558,190
9164.1.0.0/19164.1.0.1 to 164.1.31.254164.1.31.2558,190
10164.1.32.0/19164.1.32.1 to 164.1.63.254164.1.63.2558,190
11164.1.64.0/19164.1.64.1 to 164.1.95.254164.1.95.2558,190
12164.1.96.0/19164.1.96.1 to 164.1.127.254164.1.127.2558,190
13164.1.128.0/19164.1.128.1 to 164.1.159.254164.1.159.2558,190
14164.1.160.0/19164.1.160.1 to 164.1.191.254164.1.191.2558,190
15164.1.192.0/19164.1.192.1 to 164.1.223.254164.1.223.2558,190
16164.1.224.0/19164.1.224.1 to 164.1.255.254164.1.255.2558,190
17164.2.0.0/19164.2.0.1 to 164.2.31.254164.2.31.2558,190
18164.2.32.0/19164.2.32.1 to 164.2.63.254164.2.63.2558,190
19164.2.64.0/19164.2.64.1 to 164.2.95.254164.2.95.2558,190
20164.2.96.0/19164.2.96.1 to 164.2.127.254164.2.127.2558,190
21164.2.128.0/19164.2.128.1 to 164.2.159.254164.2.159.2558,190
22164.2.160.0/19164.2.160.1 to 164.2.191.254164.2.191.2558,190
23164.2.192.0/19164.2.192.1 to 164.2.223.254164.2.223.2558,190
24164.2.224.0/19164.2.224.1 to 164.2.255.254164.2.255.2558,190
25164.3.0.0/19164.3.0.1 to 164.3.31.254164.3.31.2558,190
26164.3.32.0/19164.3.32.1 to 164.3.63.254164.3.63.2558,190
27164.3.64.0/19164.3.64.1 to 164.3.95.254164.3.95.2558,190
28164.3.96.0/19164.3.96.1 to 164.3.127.254164.3.127.2558,190
29164.3.128.0/19164.3.128.1 to 164.3.159.254164.3.159.2558,190
30164.3.160.0/19164.3.160.1 to 164.3.191.254164.3.191.2558,190
31164.3.192.0/19164.3.192.1 to 164.3.223.254164.3.223.2558,190
32164.3.224.0/19164.3.224.1 to 164.3.255.254164.3.255.2558,190
33164.4.0.0/19164.4.0.1 to 164.4.31.254164.4.31.2558,190
34164.4.32.0/19164.4.32.1 to 164.4.63.254164.4.63.2558,190
35164.4.64.0/19164.4.64.1 to 164.4.95.254164.4.95.2558,190
36164.4.96.0/19164.4.96.1 to 164.4.127.254164.4.127.2558,190
37164.4.128.0/19164.4.128.1 to 164.4.159.254164.4.159.2558,190
38164.4.160.0/19164.4.160.1 to 164.4.191.254164.4.191.2558,190
39164.4.192.0/19164.4.192.1 to 164.4.223.254164.4.223.2558,190
40164.4.224.0/19164.4.224.1 to 164.4.255.254164.4.255.2558,190
41164.5.0.0/19164.5.0.1 to 164.5.31.254164.5.31.2558,190
42164.5.32.0/19164.5.32.1 to 164.5.63.254164.5.63.2558,190
43164.5.64.0/19164.5.64.1 to 164.5.95.254164.5.95.2558,190
44164.5.96.0/19164.5.96.1 to 164.5.127.254164.5.127.2558,190
45164.5.128.0/19164.5.128.1 to 164.5.159.254164.5.159.2558,190
46164.5.160.0/19164.5.160.1 to 164.5.191.254164.5.191.2558,190
47164.5.192.0/19164.5.192.1 to 164.5.223.254164.5.223.2558,190
48164.5.224.0/19164.5.224.1 to 164.5.255.254164.5.255.2558,190
49164.6.0.0/19164.6.0.1 to 164.6.31.254164.6.31.2558,190
50164.6.32.0/19164.6.32.1 to 164.6.63.254164.6.63.2558,190
51164.6.64.0/19164.6.64.1 to 164.6.95.254164.6.95.2558,190
52164.6.96.0/19164.6.96.1 to 164.6.127.254164.6.127.2558,190
53164.6.128.0/19164.6.128.1 to 164.6.159.254164.6.159.2558,190
54164.6.160.0/19164.6.160.1 to 164.6.191.254164.6.191.2558,190
55164.6.192.0/19164.6.192.1 to 164.6.223.254164.6.223.2558,190
56164.6.224.0/19164.6.224.1 to 164.6.255.254164.6.255.2558,190
57164.7.0.0/19164.7.0.1 to 164.7.31.254164.7.31.2558,190
58164.7.32.0/19164.7.32.1 to 164.7.63.254164.7.63.2558,190
59164.7.64.0/19164.7.64.1 to 164.7.95.254164.7.95.2558,190
60164.7.96.0/19164.7.96.1 to 164.7.127.254164.7.127.2558,190
61164.7.128.0/19164.7.128.1 to 164.7.159.254164.7.159.2558,190
62164.7.160.0/19164.7.160.1 to 164.7.191.254164.7.191.2558,190
63164.7.192.0/19164.7.192.1 to 164.7.223.254164.7.223.2558,190
64164.7.224.0/19164.7.224.1 to 164.7.255.254164.7.255.2558,190
65164.8.0.0/19164.8.0.1 to 164.8.31.254164.8.31.2558,190
66164.8.32.0/19164.8.32.1 to 164.8.63.254164.8.63.2558,190
67164.8.64.0/19164.8.64.1 to 164.8.95.254164.8.95.2558,190
68164.8.96.0/19164.8.96.1 to 164.8.127.254164.8.127.2558,190
69164.8.128.0/19164.8.128.1 to 164.8.159.254164.8.159.2558,190
70164.8.160.0/19164.8.160.1 to 164.8.191.254164.8.191.2558,190
71164.8.192.0/19164.8.192.1 to 164.8.223.254164.8.223.2558,190
72164.8.224.0/19164.8.224.1 to 164.8.255.254164.8.255.2558,190
73164.9.0.0/19164.9.0.1 to 164.9.31.254164.9.31.2558,190
74164.9.32.0/19164.9.32.1 to 164.9.63.254164.9.63.2558,190
75164.9.64.0/19164.9.64.1 to 164.9.95.254164.9.95.2558,190
76164.9.96.0/19164.9.96.1 to 164.9.127.254164.9.127.2558,190
77164.9.128.0/19164.9.128.1 to 164.9.159.254164.9.159.2558,190
78164.9.160.0/19164.9.160.1 to 164.9.191.254164.9.191.2558,190
79164.9.192.0/19164.9.192.1 to 164.9.223.254164.9.223.2558,190
80164.9.224.0/19164.9.224.1 to 164.9.255.254164.9.255.2558,190
81164.10.0.0/19164.10.0.1 to 164.10.31.254164.10.31.2558,190
82164.10.32.0/19164.10.32.1 to 164.10.63.254164.10.63.2558,190
83164.10.64.0/19164.10.64.1 to 164.10.95.254164.10.95.2558,190
84164.10.96.0/19164.10.96.1 to 164.10.127.254164.10.127.2558,190
85164.10.128.0/19164.10.128.1 to 164.10.159.254164.10.159.2558,190
86164.10.160.0/19164.10.160.1 to 164.10.191.254164.10.191.2558,190
87164.10.192.0/19164.10.192.1 to 164.10.223.254164.10.223.2558,190
88164.10.224.0/19164.10.224.1 to 164.10.255.254164.10.255.2558,190
89164.11.0.0/19164.11.0.1 to 164.11.31.254164.11.31.2558,190
90164.11.32.0/19164.11.32.1 to 164.11.63.254164.11.63.2558,190
91164.11.64.0/19164.11.64.1 to 164.11.95.254164.11.95.2558,190
92164.11.96.0/19164.11.96.1 to 164.11.127.254164.11.127.2558,190
93164.11.128.0/19164.11.128.1 to 164.11.159.254164.11.159.2558,190
94164.11.160.0/19164.11.160.1 to 164.11.191.254164.11.191.2558,190
95164.11.192.0/19164.11.192.1 to 164.11.223.254164.11.223.2558,190
96164.11.224.0/19164.11.224.1 to 164.11.255.254164.11.255.2558,190
97164.12.0.0/19164.12.0.1 to 164.12.31.254164.12.31.2558,190
98164.12.32.0/19164.12.32.1 to 164.12.63.254164.12.63.2558,190
99164.12.64.0/19164.12.64.1 to 164.12.95.254164.12.95.2558,190
100164.12.96.0/19164.12.96.1 to 164.12.127.254164.12.127.2558,190
101164.12.128.0/19164.12.128.1 to 164.12.159.254164.12.159.2558,190
102164.12.160.0/19164.12.160.1 to 164.12.191.254164.12.191.2558,190
103164.12.192.0/19164.12.192.1 to 164.12.223.254164.12.223.2558,190
104164.12.224.0/19164.12.224.1 to 164.12.255.254164.12.255.2558,190
105164.13.0.0/19164.13.0.1 to 164.13.31.254164.13.31.2558,190
106164.13.32.0/19164.13.32.1 to 164.13.63.254164.13.63.2558,190
107164.13.64.0/19164.13.64.1 to 164.13.95.254164.13.95.2558,190
108164.13.96.0/19164.13.96.1 to 164.13.127.254164.13.127.2558,190
109164.13.128.0/19164.13.128.1 to 164.13.159.254164.13.159.2558,190
110164.13.160.0/19164.13.160.1 to 164.13.191.254164.13.191.2558,190
111164.13.192.0/19164.13.192.1 to 164.13.223.254164.13.223.2558,190
112164.13.224.0/19164.13.224.1 to 164.13.255.254164.13.255.2558,190
113164.14.0.0/19164.14.0.1 to 164.14.31.254164.14.31.2558,190
114164.14.32.0/19164.14.32.1 to 164.14.63.254164.14.63.2558,190
115164.14.64.0/19164.14.64.1 to 164.14.95.254164.14.95.2558,190
116164.14.96.0/19164.14.96.1 to 164.14.127.254164.14.127.2558,190
117164.14.128.0/19164.14.128.1 to 164.14.159.254164.14.159.2558,190
118164.14.160.0/19164.14.160.1 to 164.14.191.254164.14.191.2558,190
119164.14.192.0/19164.14.192.1 to 164.14.223.254164.14.223.2558,190
120164.14.224.0/19164.14.224.1 to 164.14.255.254164.14.255.2558,190
121164.15.0.0/19164.15.0.1 to 164.15.31.254164.15.31.2558,190
122164.15.32.0/19164.15.32.1 to 164.15.63.254164.15.63.2558,190
123164.15.64.0/19164.15.64.1 to 164.15.95.254164.15.95.2558,190
124164.15.96.0/19164.15.96.1 to 164.15.127.254164.15.127.2558,190
125164.15.128.0/19164.15.128.1 to 164.15.159.254164.15.159.2558,190
126164.15.160.0/19164.15.160.1 to 164.15.191.254164.15.191.2558,190
127164.15.192.0/19164.15.192.1 to 164.15.223.254164.15.223.2558,190
128164.15.224.0/19164.15.224.1 to 164.15.255.254164.15.255.2558,190
129164.16.0.0/19164.16.0.1 to 164.16.31.254164.16.31.2558,190
130164.16.32.0/19164.16.32.1 to 164.16.63.254164.16.63.2558,190
131164.16.64.0/19164.16.64.1 to 164.16.95.254164.16.95.2558,190
132164.16.96.0/19164.16.96.1 to 164.16.127.254164.16.127.2558,190
133164.16.128.0/19164.16.128.1 to 164.16.159.254164.16.159.2558,190
134164.16.160.0/19164.16.160.1 to 164.16.191.254164.16.191.2558,190
135164.16.192.0/19164.16.192.1 to 164.16.223.254164.16.223.2558,190
136164.16.224.0/19164.16.224.1 to 164.16.255.254164.16.255.2558,190
137164.17.0.0/19164.17.0.1 to 164.17.31.254164.17.31.2558,190
138164.17.32.0/19164.17.32.1 to 164.17.63.254164.17.63.2558,190
139164.17.64.0/19164.17.64.1 to 164.17.95.254164.17.95.2558,190
140164.17.96.0/19164.17.96.1 to 164.17.127.254164.17.127.2558,190
141164.17.128.0/19164.17.128.1 to 164.17.159.254164.17.159.2558,190
142164.17.160.0/19164.17.160.1 to 164.17.191.254164.17.191.2558,190
143164.17.192.0/19164.17.192.1 to 164.17.223.254164.17.223.2558,190
144164.17.224.0/19164.17.224.1 to 164.17.255.254164.17.255.2558,190
145164.18.0.0/19164.18.0.1 to 164.18.31.254164.18.31.2558,190
146164.18.32.0/19164.18.32.1 to 164.18.63.254164.18.63.2558,190
147164.18.64.0/19164.18.64.1 to 164.18.95.254164.18.95.2558,190
148164.18.96.0/19164.18.96.1 to 164.18.127.254164.18.127.2558,190
149164.18.128.0/19164.18.128.1 to 164.18.159.254164.18.159.2558,190
150164.18.160.0/19164.18.160.1 to 164.18.191.254164.18.191.2558,190
151164.18.192.0/19164.18.192.1 to 164.18.223.254164.18.223.2558,190
152164.18.224.0/19164.18.224.1 to 164.18.255.254164.18.255.2558,190
153164.19.0.0/19164.19.0.1 to 164.19.31.254164.19.31.2558,190
154164.19.32.0/19164.19.32.1 to 164.19.63.254164.19.63.2558,190
155164.19.64.0/19164.19.64.1 to 164.19.95.254164.19.95.2558,190
156164.19.96.0/19164.19.96.1 to 164.19.127.254164.19.127.2558,190
157164.19.128.0/19164.19.128.1 to 164.19.159.254164.19.159.2558,190
158164.19.160.0/19164.19.160.1 to 164.19.191.254164.19.191.2558,190
159164.19.192.0/19164.19.192.1 to 164.19.223.254164.19.223.2558,190
160164.19.224.0/19164.19.224.1 to 164.19.255.254164.19.255.2558,190
161164.20.0.0/19164.20.0.1 to 164.20.31.254164.20.31.2558,190
162164.20.32.0/19164.20.32.1 to 164.20.63.254164.20.63.2558,190
163164.20.64.0/19164.20.64.1 to 164.20.95.254164.20.95.2558,190
164164.20.96.0/19164.20.96.1 to 164.20.127.254164.20.127.2558,190
165164.20.128.0/19164.20.128.1 to 164.20.159.254164.20.159.2558,190
166164.20.160.0/19164.20.160.1 to 164.20.191.254164.20.191.2558,190
167164.20.192.0/19164.20.192.1 to 164.20.223.254164.20.223.2558,190
168164.20.224.0/19164.20.224.1 to 164.20.255.254164.20.255.2558,190
169164.21.0.0/19164.21.0.1 to 164.21.31.254164.21.31.2558,190
170164.21.32.0/19164.21.32.1 to 164.21.63.254164.21.63.2558,190
171164.21.64.0/19164.21.64.1 to 164.21.95.254164.21.95.2558,190
172164.21.96.0/19164.21.96.1 to 164.21.127.254164.21.127.2558,190
173164.21.128.0/19164.21.128.1 to 164.21.159.254164.21.159.2558,190
174164.21.160.0/19164.21.160.1 to 164.21.191.254164.21.191.2558,190
175164.21.192.0/19164.21.192.1 to 164.21.223.254164.21.223.2558,190
176164.21.224.0/19164.21.224.1 to 164.21.255.254164.21.255.2558,190
177164.22.0.0/19164.22.0.1 to 164.22.31.254164.22.31.2558,190
178164.22.32.0/19164.22.32.1 to 164.22.63.254164.22.63.2558,190
179164.22.64.0/19164.22.64.1 to 164.22.95.254164.22.95.2558,190
180164.22.96.0/19164.22.96.1 to 164.22.127.254164.22.127.2558,190
181164.22.128.0/19164.22.128.1 to 164.22.159.254164.22.159.2558,190
182164.22.160.0/19164.22.160.1 to 164.22.191.254164.22.191.2558,190
183164.22.192.0/19164.22.192.1 to 164.22.223.254164.22.223.2558,190
184164.22.224.0/19164.22.224.1 to 164.22.255.254164.22.255.2558,190
185164.23.0.0/19164.23.0.1 to 164.23.31.254164.23.31.2558,190
186164.23.32.0/19164.23.32.1 to 164.23.63.254164.23.63.2558,190
187164.23.64.0/19164.23.64.1 to 164.23.95.254164.23.95.2558,190
188164.23.96.0/19164.23.96.1 to 164.23.127.254164.23.127.2558,190
189164.23.128.0/19164.23.128.1 to 164.23.159.254164.23.159.2558,190
190164.23.160.0/19164.23.160.1 to 164.23.191.254164.23.191.2558,190
191164.23.192.0/19164.23.192.1 to 164.23.223.254164.23.223.2558,190
192164.23.224.0/19164.23.224.1 to 164.23.255.254164.23.255.2558,190
193164.24.0.0/19164.24.0.1 to 164.24.31.254164.24.31.2558,190
194164.24.32.0/19164.24.32.1 to 164.24.63.254164.24.63.2558,190
195164.24.64.0/19164.24.64.1 to 164.24.95.254164.24.95.2558,190
196164.24.96.0/19164.24.96.1 to 164.24.127.254164.24.127.2558,190
197164.24.128.0/19164.24.128.1 to 164.24.159.254164.24.159.2558,190
198164.24.160.0/19164.24.160.1 to 164.24.191.254164.24.191.2558,190
199164.24.192.0/19164.24.192.1 to 164.24.223.254164.24.223.2558,190
200164.24.224.0/19164.24.224.1 to 164.24.255.254164.24.255.2558,190
201164.25.0.0/19164.25.0.1 to 164.25.31.254164.25.31.2558,190
202164.25.32.0/19164.25.32.1 to 164.25.63.254164.25.63.2558,190
203164.25.64.0/19164.25.64.1 to 164.25.95.254164.25.95.2558,190
204164.25.96.0/19164.25.96.1 to 164.25.127.254164.25.127.2558,190
205164.25.128.0/19164.25.128.1 to 164.25.159.254164.25.159.2558,190
206164.25.160.0/19164.25.160.1 to 164.25.191.254164.25.191.2558,190
207164.25.192.0/19164.25.192.1 to 164.25.223.254164.25.223.2558,190
208164.25.224.0/19164.25.224.1 to 164.25.255.254164.25.255.2558,190
209164.26.0.0/19164.26.0.1 to 164.26.31.254164.26.31.2558,190
210164.26.32.0/19164.26.32.1 to 164.26.63.254164.26.63.2558,190
211164.26.64.0/19164.26.64.1 to 164.26.95.254164.26.95.2558,190
212164.26.96.0/19164.26.96.1 to 164.26.127.254164.26.127.2558,190
213164.26.128.0/19164.26.128.1 to 164.26.159.254164.26.159.2558,190
214164.26.160.0/19164.26.160.1 to 164.26.191.254164.26.191.2558,190
215164.26.192.0/19164.26.192.1 to 164.26.223.254164.26.223.2558,190
216164.26.224.0/19164.26.224.1 to 164.26.255.254164.26.255.2558,190
217164.27.0.0/19164.27.0.1 to 164.27.31.254164.27.31.2558,190
218164.27.32.0/19164.27.32.1 to 164.27.63.254164.27.63.2558,190
219164.27.64.0/19164.27.64.1 to 164.27.95.254164.27.95.2558,190
220164.27.96.0/19164.27.96.1 to 164.27.127.254164.27.127.2558,190
221164.27.128.0/19164.27.128.1 to 164.27.159.254164.27.159.2558,190
222164.27.160.0/19164.27.160.1 to 164.27.191.254164.27.191.2558,190
223164.27.192.0/19164.27.192.1 to 164.27.223.254164.27.223.2558,190
224164.27.224.0/19164.27.224.1 to 164.27.255.254164.27.255.2558,190
225164.28.0.0/19164.28.0.1 to 164.28.31.254164.28.31.2558,190
226164.28.32.0/19164.28.32.1 to 164.28.63.254164.28.63.2558,190
227164.28.64.0/19164.28.64.1 to 164.28.95.254164.28.95.2558,190
228164.28.96.0/19164.28.96.1 to 164.28.127.254164.28.127.2558,190
229164.28.128.0/19164.28.128.1 to 164.28.159.254164.28.159.2558,190
230164.28.160.0/19164.28.160.1 to 164.28.191.254164.28.191.2558,190
231164.28.192.0/19164.28.192.1 to 164.28.223.254164.28.223.2558,190
232164.28.224.0/19164.28.224.1 to 164.28.255.254164.28.255.2558,190
233164.29.0.0/19164.29.0.1 to 164.29.31.254164.29.31.2558,190
234164.29.32.0/19164.29.32.1 to 164.29.63.254164.29.63.2558,190
235164.29.64.0/19164.29.64.1 to 164.29.95.254164.29.95.2558,190
236164.29.96.0/19164.29.96.1 to 164.29.127.254164.29.127.2558,190
237164.29.128.0/19164.29.128.1 to 164.29.159.254164.29.159.2558,190
238164.29.160.0/19164.29.160.1 to 164.29.191.254164.29.191.2558,190
239164.29.192.0/19164.29.192.1 to 164.29.223.254164.29.223.2558,190
240164.29.224.0/19164.29.224.1 to 164.29.255.254164.29.255.2558,190
241164.30.0.0/19164.30.0.1 to 164.30.31.254164.30.31.2558,190
242164.30.32.0/19164.30.32.1 to 164.30.63.254164.30.63.2558,190
243164.30.64.0/19164.30.64.1 to 164.30.95.254164.30.95.2558,190
244164.30.96.0/19164.30.96.1 to 164.30.127.254164.30.127.2558,190
245164.30.128.0/19164.30.128.1 to 164.30.159.254164.30.159.2558,190
246164.30.160.0/19164.30.160.1 to 164.30.191.254164.30.191.2558,190
247164.30.192.0/19164.30.192.1 to 164.30.223.254164.30.223.2558,190
248164.30.224.0/19164.30.224.1 to 164.30.255.254164.30.255.2558,190
249164.31.0.0/19164.31.0.1 to 164.31.31.254164.31.31.2558,190
250164.31.32.0/19164.31.32.1 to 164.31.63.254164.31.63.2558,190
251164.31.64.0/19164.31.64.1 to 164.31.95.254164.31.95.2558,190
252164.31.96.0/19164.31.96.1 to 164.31.127.254164.31.127.2558,190
253164.31.128.0/19164.31.128.1 to 164.31.159.254164.31.159.2558,190
254164.31.160.0/19164.31.160.1 to 164.31.191.254164.31.191.2558,190
255164.31.192.0/19164.31.192.1 to 164.31.223.254164.31.223.2558,190
256164.31.224.0/19164.31.224.1 to 164.31.255.254164.31.255.2558,190

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.