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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/18
/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 1,024 subnets of /18; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1164.0.0.0/18164.0.0.1 to 164.0.63.254164.0.63.25516,382
2164.0.64.0/18164.0.64.1 to 164.0.127.254164.0.127.25516,382
3164.0.128.0/18164.0.128.1 to 164.0.191.254164.0.191.25516,382
4164.0.192.0/18164.0.192.1 to 164.0.255.254164.0.255.25516,382
5164.1.0.0/18164.1.0.1 to 164.1.63.254164.1.63.25516,382
6164.1.64.0/18164.1.64.1 to 164.1.127.254164.1.127.25516,382
7164.1.128.0/18164.1.128.1 to 164.1.191.254164.1.191.25516,382
8164.1.192.0/18164.1.192.1 to 164.1.255.254164.1.255.25516,382
9164.2.0.0/18164.2.0.1 to 164.2.63.254164.2.63.25516,382
10164.2.64.0/18164.2.64.1 to 164.2.127.254164.2.127.25516,382
11164.2.128.0/18164.2.128.1 to 164.2.191.254164.2.191.25516,382
12164.2.192.0/18164.2.192.1 to 164.2.255.254164.2.255.25516,382
13164.3.0.0/18164.3.0.1 to 164.3.63.254164.3.63.25516,382
14164.3.64.0/18164.3.64.1 to 164.3.127.254164.3.127.25516,382
15164.3.128.0/18164.3.128.1 to 164.3.191.254164.3.191.25516,382
16164.3.192.0/18164.3.192.1 to 164.3.255.254164.3.255.25516,382
17164.4.0.0/18164.4.0.1 to 164.4.63.254164.4.63.25516,382
18164.4.64.0/18164.4.64.1 to 164.4.127.254164.4.127.25516,382
19164.4.128.0/18164.4.128.1 to 164.4.191.254164.4.191.25516,382
20164.4.192.0/18164.4.192.1 to 164.4.255.254164.4.255.25516,382
21164.5.0.0/18164.5.0.1 to 164.5.63.254164.5.63.25516,382
22164.5.64.0/18164.5.64.1 to 164.5.127.254164.5.127.25516,382
23164.5.128.0/18164.5.128.1 to 164.5.191.254164.5.191.25516,382
24164.5.192.0/18164.5.192.1 to 164.5.255.254164.5.255.25516,382
25164.6.0.0/18164.6.0.1 to 164.6.63.254164.6.63.25516,382
26164.6.64.0/18164.6.64.1 to 164.6.127.254164.6.127.25516,382
27164.6.128.0/18164.6.128.1 to 164.6.191.254164.6.191.25516,382
28164.6.192.0/18164.6.192.1 to 164.6.255.254164.6.255.25516,382
29164.7.0.0/18164.7.0.1 to 164.7.63.254164.7.63.25516,382
30164.7.64.0/18164.7.64.1 to 164.7.127.254164.7.127.25516,382
31164.7.128.0/18164.7.128.1 to 164.7.191.254164.7.191.25516,382
32164.7.192.0/18164.7.192.1 to 164.7.255.254164.7.255.25516,382
33164.8.0.0/18164.8.0.1 to 164.8.63.254164.8.63.25516,382
34164.8.64.0/18164.8.64.1 to 164.8.127.254164.8.127.25516,382
35164.8.128.0/18164.8.128.1 to 164.8.191.254164.8.191.25516,382
36164.8.192.0/18164.8.192.1 to 164.8.255.254164.8.255.25516,382
37164.9.0.0/18164.9.0.1 to 164.9.63.254164.9.63.25516,382
38164.9.64.0/18164.9.64.1 to 164.9.127.254164.9.127.25516,382
39164.9.128.0/18164.9.128.1 to 164.9.191.254164.9.191.25516,382
40164.9.192.0/18164.9.192.1 to 164.9.255.254164.9.255.25516,382
41164.10.0.0/18164.10.0.1 to 164.10.63.254164.10.63.25516,382
42164.10.64.0/18164.10.64.1 to 164.10.127.254164.10.127.25516,382
43164.10.128.0/18164.10.128.1 to 164.10.191.254164.10.191.25516,382
44164.10.192.0/18164.10.192.1 to 164.10.255.254164.10.255.25516,382
45164.11.0.0/18164.11.0.1 to 164.11.63.254164.11.63.25516,382
46164.11.64.0/18164.11.64.1 to 164.11.127.254164.11.127.25516,382
47164.11.128.0/18164.11.128.1 to 164.11.191.254164.11.191.25516,382
48164.11.192.0/18164.11.192.1 to 164.11.255.254164.11.255.25516,382
49164.12.0.0/18164.12.0.1 to 164.12.63.254164.12.63.25516,382
50164.12.64.0/18164.12.64.1 to 164.12.127.254164.12.127.25516,382
51164.12.128.0/18164.12.128.1 to 164.12.191.254164.12.191.25516,382
52164.12.192.0/18164.12.192.1 to 164.12.255.254164.12.255.25516,382
53164.13.0.0/18164.13.0.1 to 164.13.63.254164.13.63.25516,382
54164.13.64.0/18164.13.64.1 to 164.13.127.254164.13.127.25516,382
55164.13.128.0/18164.13.128.1 to 164.13.191.254164.13.191.25516,382
56164.13.192.0/18164.13.192.1 to 164.13.255.254164.13.255.25516,382
57164.14.0.0/18164.14.0.1 to 164.14.63.254164.14.63.25516,382
58164.14.64.0/18164.14.64.1 to 164.14.127.254164.14.127.25516,382
59164.14.128.0/18164.14.128.1 to 164.14.191.254164.14.191.25516,382
60164.14.192.0/18164.14.192.1 to 164.14.255.254164.14.255.25516,382
61164.15.0.0/18164.15.0.1 to 164.15.63.254164.15.63.25516,382
62164.15.64.0/18164.15.64.1 to 164.15.127.254164.15.127.25516,382
63164.15.128.0/18164.15.128.1 to 164.15.191.254164.15.191.25516,382
64164.15.192.0/18164.15.192.1 to 164.15.255.254164.15.255.25516,382
65164.16.0.0/18164.16.0.1 to 164.16.63.254164.16.63.25516,382
66164.16.64.0/18164.16.64.1 to 164.16.127.254164.16.127.25516,382
67164.16.128.0/18164.16.128.1 to 164.16.191.254164.16.191.25516,382
68164.16.192.0/18164.16.192.1 to 164.16.255.254164.16.255.25516,382
69164.17.0.0/18164.17.0.1 to 164.17.63.254164.17.63.25516,382
70164.17.64.0/18164.17.64.1 to 164.17.127.254164.17.127.25516,382
71164.17.128.0/18164.17.128.1 to 164.17.191.254164.17.191.25516,382
72164.17.192.0/18164.17.192.1 to 164.17.255.254164.17.255.25516,382
73164.18.0.0/18164.18.0.1 to 164.18.63.254164.18.63.25516,382
74164.18.64.0/18164.18.64.1 to 164.18.127.254164.18.127.25516,382
75164.18.128.0/18164.18.128.1 to 164.18.191.254164.18.191.25516,382
76164.18.192.0/18164.18.192.1 to 164.18.255.254164.18.255.25516,382
77164.19.0.0/18164.19.0.1 to 164.19.63.254164.19.63.25516,382
78164.19.64.0/18164.19.64.1 to 164.19.127.254164.19.127.25516,382
79164.19.128.0/18164.19.128.1 to 164.19.191.254164.19.191.25516,382
80164.19.192.0/18164.19.192.1 to 164.19.255.254164.19.255.25516,382
81164.20.0.0/18164.20.0.1 to 164.20.63.254164.20.63.25516,382
82164.20.64.0/18164.20.64.1 to 164.20.127.254164.20.127.25516,382
83164.20.128.0/18164.20.128.1 to 164.20.191.254164.20.191.25516,382
84164.20.192.0/18164.20.192.1 to 164.20.255.254164.20.255.25516,382
85164.21.0.0/18164.21.0.1 to 164.21.63.254164.21.63.25516,382
86164.21.64.0/18164.21.64.1 to 164.21.127.254164.21.127.25516,382
87164.21.128.0/18164.21.128.1 to 164.21.191.254164.21.191.25516,382
88164.21.192.0/18164.21.192.1 to 164.21.255.254164.21.255.25516,382
89164.22.0.0/18164.22.0.1 to 164.22.63.254164.22.63.25516,382
90164.22.64.0/18164.22.64.1 to 164.22.127.254164.22.127.25516,382
91164.22.128.0/18164.22.128.1 to 164.22.191.254164.22.191.25516,382
92164.22.192.0/18164.22.192.1 to 164.22.255.254164.22.255.25516,382
93164.23.0.0/18164.23.0.1 to 164.23.63.254164.23.63.25516,382
94164.23.64.0/18164.23.64.1 to 164.23.127.254164.23.127.25516,382
95164.23.128.0/18164.23.128.1 to 164.23.191.254164.23.191.25516,382
96164.23.192.0/18164.23.192.1 to 164.23.255.254164.23.255.25516,382
97164.24.0.0/18164.24.0.1 to 164.24.63.254164.24.63.25516,382
98164.24.64.0/18164.24.64.1 to 164.24.127.254164.24.127.25516,382
99164.24.128.0/18164.24.128.1 to 164.24.191.254164.24.191.25516,382
100164.24.192.0/18164.24.192.1 to 164.24.255.254164.24.255.25516,382
101164.25.0.0/18164.25.0.1 to 164.25.63.254164.25.63.25516,382
102164.25.64.0/18164.25.64.1 to 164.25.127.254164.25.127.25516,382
103164.25.128.0/18164.25.128.1 to 164.25.191.254164.25.191.25516,382
104164.25.192.0/18164.25.192.1 to 164.25.255.254164.25.255.25516,382
105164.26.0.0/18164.26.0.1 to 164.26.63.254164.26.63.25516,382
106164.26.64.0/18164.26.64.1 to 164.26.127.254164.26.127.25516,382
107164.26.128.0/18164.26.128.1 to 164.26.191.254164.26.191.25516,382
108164.26.192.0/18164.26.192.1 to 164.26.255.254164.26.255.25516,382
109164.27.0.0/18164.27.0.1 to 164.27.63.254164.27.63.25516,382
110164.27.64.0/18164.27.64.1 to 164.27.127.254164.27.127.25516,382
111164.27.128.0/18164.27.128.1 to 164.27.191.254164.27.191.25516,382
112164.27.192.0/18164.27.192.1 to 164.27.255.254164.27.255.25516,382
113164.28.0.0/18164.28.0.1 to 164.28.63.254164.28.63.25516,382
114164.28.64.0/18164.28.64.1 to 164.28.127.254164.28.127.25516,382
115164.28.128.0/18164.28.128.1 to 164.28.191.254164.28.191.25516,382
116164.28.192.0/18164.28.192.1 to 164.28.255.254164.28.255.25516,382
117164.29.0.0/18164.29.0.1 to 164.29.63.254164.29.63.25516,382
118164.29.64.0/18164.29.64.1 to 164.29.127.254164.29.127.25516,382
119164.29.128.0/18164.29.128.1 to 164.29.191.254164.29.191.25516,382
120164.29.192.0/18164.29.192.1 to 164.29.255.254164.29.255.25516,382
121164.30.0.0/18164.30.0.1 to 164.30.63.254164.30.63.25516,382
122164.30.64.0/18164.30.64.1 to 164.30.127.254164.30.127.25516,382
123164.30.128.0/18164.30.128.1 to 164.30.191.254164.30.191.25516,382
124164.30.192.0/18164.30.192.1 to 164.30.255.254164.30.255.25516,382
125164.31.0.0/18164.31.0.1 to 164.31.63.254164.31.63.25516,382
126164.31.64.0/18164.31.64.1 to 164.31.127.254164.31.127.25516,382
127164.31.128.0/18164.31.128.1 to 164.31.191.254164.31.191.25516,382
128164.31.192.0/18164.31.192.1 to 164.31.255.254164.31.255.25516,382
129164.32.0.0/18164.32.0.1 to 164.32.63.254164.32.63.25516,382
130164.32.64.0/18164.32.64.1 to 164.32.127.254164.32.127.25516,382
131164.32.128.0/18164.32.128.1 to 164.32.191.254164.32.191.25516,382
132164.32.192.0/18164.32.192.1 to 164.32.255.254164.32.255.25516,382
133164.33.0.0/18164.33.0.1 to 164.33.63.254164.33.63.25516,382
134164.33.64.0/18164.33.64.1 to 164.33.127.254164.33.127.25516,382
135164.33.128.0/18164.33.128.1 to 164.33.191.254164.33.191.25516,382
136164.33.192.0/18164.33.192.1 to 164.33.255.254164.33.255.25516,382
137164.34.0.0/18164.34.0.1 to 164.34.63.254164.34.63.25516,382
138164.34.64.0/18164.34.64.1 to 164.34.127.254164.34.127.25516,382
139164.34.128.0/18164.34.128.1 to 164.34.191.254164.34.191.25516,382
140164.34.192.0/18164.34.192.1 to 164.34.255.254164.34.255.25516,382
141164.35.0.0/18164.35.0.1 to 164.35.63.254164.35.63.25516,382
142164.35.64.0/18164.35.64.1 to 164.35.127.254164.35.127.25516,382
143164.35.128.0/18164.35.128.1 to 164.35.191.254164.35.191.25516,382
144164.35.192.0/18164.35.192.1 to 164.35.255.254164.35.255.25516,382
145164.36.0.0/18164.36.0.1 to 164.36.63.254164.36.63.25516,382
146164.36.64.0/18164.36.64.1 to 164.36.127.254164.36.127.25516,382
147164.36.128.0/18164.36.128.1 to 164.36.191.254164.36.191.25516,382
148164.36.192.0/18164.36.192.1 to 164.36.255.254164.36.255.25516,382
149164.37.0.0/18164.37.0.1 to 164.37.63.254164.37.63.25516,382
150164.37.64.0/18164.37.64.1 to 164.37.127.254164.37.127.25516,382
151164.37.128.0/18164.37.128.1 to 164.37.191.254164.37.191.25516,382
152164.37.192.0/18164.37.192.1 to 164.37.255.254164.37.255.25516,382
153164.38.0.0/18164.38.0.1 to 164.38.63.254164.38.63.25516,382
154164.38.64.0/18164.38.64.1 to 164.38.127.254164.38.127.25516,382
155164.38.128.0/18164.38.128.1 to 164.38.191.254164.38.191.25516,382
156164.38.192.0/18164.38.192.1 to 164.38.255.254164.38.255.25516,382
157164.39.0.0/18164.39.0.1 to 164.39.63.254164.39.63.25516,382
158164.39.64.0/18164.39.64.1 to 164.39.127.254164.39.127.25516,382
159164.39.128.0/18164.39.128.1 to 164.39.191.254164.39.191.25516,382
160164.39.192.0/18164.39.192.1 to 164.39.255.254164.39.255.25516,382
161164.40.0.0/18164.40.0.1 to 164.40.63.254164.40.63.25516,382
162164.40.64.0/18164.40.64.1 to 164.40.127.254164.40.127.25516,382
163164.40.128.0/18164.40.128.1 to 164.40.191.254164.40.191.25516,382
164164.40.192.0/18164.40.192.1 to 164.40.255.254164.40.255.25516,382
165164.41.0.0/18164.41.0.1 to 164.41.63.254164.41.63.25516,382
166164.41.64.0/18164.41.64.1 to 164.41.127.254164.41.127.25516,382
167164.41.128.0/18164.41.128.1 to 164.41.191.254164.41.191.25516,382
168164.41.192.0/18164.41.192.1 to 164.41.255.254164.41.255.25516,382
169164.42.0.0/18164.42.0.1 to 164.42.63.254164.42.63.25516,382
170164.42.64.0/18164.42.64.1 to 164.42.127.254164.42.127.25516,382
171164.42.128.0/18164.42.128.1 to 164.42.191.254164.42.191.25516,382
172164.42.192.0/18164.42.192.1 to 164.42.255.254164.42.255.25516,382
173164.43.0.0/18164.43.0.1 to 164.43.63.254164.43.63.25516,382
174164.43.64.0/18164.43.64.1 to 164.43.127.254164.43.127.25516,382
175164.43.128.0/18164.43.128.1 to 164.43.191.254164.43.191.25516,382
176164.43.192.0/18164.43.192.1 to 164.43.255.254164.43.255.25516,382
177164.44.0.0/18164.44.0.1 to 164.44.63.254164.44.63.25516,382
178164.44.64.0/18164.44.64.1 to 164.44.127.254164.44.127.25516,382
179164.44.128.0/18164.44.128.1 to 164.44.191.254164.44.191.25516,382
180164.44.192.0/18164.44.192.1 to 164.44.255.254164.44.255.25516,382
181164.45.0.0/18164.45.0.1 to 164.45.63.254164.45.63.25516,382
182164.45.64.0/18164.45.64.1 to 164.45.127.254164.45.127.25516,382
183164.45.128.0/18164.45.128.1 to 164.45.191.254164.45.191.25516,382
184164.45.192.0/18164.45.192.1 to 164.45.255.254164.45.255.25516,382
185164.46.0.0/18164.46.0.1 to 164.46.63.254164.46.63.25516,382
186164.46.64.0/18164.46.64.1 to 164.46.127.254164.46.127.25516,382
187164.46.128.0/18164.46.128.1 to 164.46.191.254164.46.191.25516,382
188164.46.192.0/18164.46.192.1 to 164.46.255.254164.46.255.25516,382
189164.47.0.0/18164.47.0.1 to 164.47.63.254164.47.63.25516,382
190164.47.64.0/18164.47.64.1 to 164.47.127.254164.47.127.25516,382
191164.47.128.0/18164.47.128.1 to 164.47.191.254164.47.191.25516,382
192164.47.192.0/18164.47.192.1 to 164.47.255.254164.47.255.25516,382
193164.48.0.0/18164.48.0.1 to 164.48.63.254164.48.63.25516,382
194164.48.64.0/18164.48.64.1 to 164.48.127.254164.48.127.25516,382
195164.48.128.0/18164.48.128.1 to 164.48.191.254164.48.191.25516,382
196164.48.192.0/18164.48.192.1 to 164.48.255.254164.48.255.25516,382
197164.49.0.0/18164.49.0.1 to 164.49.63.254164.49.63.25516,382
198164.49.64.0/18164.49.64.1 to 164.49.127.254164.49.127.25516,382
199164.49.128.0/18164.49.128.1 to 164.49.191.254164.49.191.25516,382
200164.49.192.0/18164.49.192.1 to 164.49.255.254164.49.255.25516,382
201164.50.0.0/18164.50.0.1 to 164.50.63.254164.50.63.25516,382
202164.50.64.0/18164.50.64.1 to 164.50.127.254164.50.127.25516,382
203164.50.128.0/18164.50.128.1 to 164.50.191.254164.50.191.25516,382
204164.50.192.0/18164.50.192.1 to 164.50.255.254164.50.255.25516,382
205164.51.0.0/18164.51.0.1 to 164.51.63.254164.51.63.25516,382
206164.51.64.0/18164.51.64.1 to 164.51.127.254164.51.127.25516,382
207164.51.128.0/18164.51.128.1 to 164.51.191.254164.51.191.25516,382
208164.51.192.0/18164.51.192.1 to 164.51.255.254164.51.255.25516,382
209164.52.0.0/18164.52.0.1 to 164.52.63.254164.52.63.25516,382
210164.52.64.0/18164.52.64.1 to 164.52.127.254164.52.127.25516,382
211164.52.128.0/18164.52.128.1 to 164.52.191.254164.52.191.25516,382
212164.52.192.0/18164.52.192.1 to 164.52.255.254164.52.255.25516,382
213164.53.0.0/18164.53.0.1 to 164.53.63.254164.53.63.25516,382
214164.53.64.0/18164.53.64.1 to 164.53.127.254164.53.127.25516,382
215164.53.128.0/18164.53.128.1 to 164.53.191.254164.53.191.25516,382
216164.53.192.0/18164.53.192.1 to 164.53.255.254164.53.255.25516,382
217164.54.0.0/18164.54.0.1 to 164.54.63.254164.54.63.25516,382
218164.54.64.0/18164.54.64.1 to 164.54.127.254164.54.127.25516,382
219164.54.128.0/18164.54.128.1 to 164.54.191.254164.54.191.25516,382
220164.54.192.0/18164.54.192.1 to 164.54.255.254164.54.255.25516,382
221164.55.0.0/18164.55.0.1 to 164.55.63.254164.55.63.25516,382
222164.55.64.0/18164.55.64.1 to 164.55.127.254164.55.127.25516,382
223164.55.128.0/18164.55.128.1 to 164.55.191.254164.55.191.25516,382
224164.55.192.0/18164.55.192.1 to 164.55.255.254164.55.255.25516,382
225164.56.0.0/18164.56.0.1 to 164.56.63.254164.56.63.25516,382
226164.56.64.0/18164.56.64.1 to 164.56.127.254164.56.127.25516,382
227164.56.128.0/18164.56.128.1 to 164.56.191.254164.56.191.25516,382
228164.56.192.0/18164.56.192.1 to 164.56.255.254164.56.255.25516,382
229164.57.0.0/18164.57.0.1 to 164.57.63.254164.57.63.25516,382
230164.57.64.0/18164.57.64.1 to 164.57.127.254164.57.127.25516,382
231164.57.128.0/18164.57.128.1 to 164.57.191.254164.57.191.25516,382
232164.57.192.0/18164.57.192.1 to 164.57.255.254164.57.255.25516,382
233164.58.0.0/18164.58.0.1 to 164.58.63.254164.58.63.25516,382
234164.58.64.0/18164.58.64.1 to 164.58.127.254164.58.127.25516,382
235164.58.128.0/18164.58.128.1 to 164.58.191.254164.58.191.25516,382
236164.58.192.0/18164.58.192.1 to 164.58.255.254164.58.255.25516,382
237164.59.0.0/18164.59.0.1 to 164.59.63.254164.59.63.25516,382
238164.59.64.0/18164.59.64.1 to 164.59.127.254164.59.127.25516,382
239164.59.128.0/18164.59.128.1 to 164.59.191.254164.59.191.25516,382
240164.59.192.0/18164.59.192.1 to 164.59.255.254164.59.255.25516,382
241164.60.0.0/18164.60.0.1 to 164.60.63.254164.60.63.25516,382
242164.60.64.0/18164.60.64.1 to 164.60.127.254164.60.127.25516,382
243164.60.128.0/18164.60.128.1 to 164.60.191.254164.60.191.25516,382
244164.60.192.0/18164.60.192.1 to 164.60.255.254164.60.255.25516,382
245164.61.0.0/18164.61.0.1 to 164.61.63.254164.61.63.25516,382
246164.61.64.0/18164.61.64.1 to 164.61.127.254164.61.127.25516,382
247164.61.128.0/18164.61.128.1 to 164.61.191.254164.61.191.25516,382
248164.61.192.0/18164.61.192.1 to 164.61.255.254164.61.255.25516,382
249164.62.0.0/18164.62.0.1 to 164.62.63.254164.62.63.25516,382
250164.62.64.0/18164.62.64.1 to 164.62.127.254164.62.127.25516,382
251164.62.128.0/18164.62.128.1 to 164.62.191.254164.62.191.25516,382
252164.62.192.0/18164.62.192.1 to 164.62.255.254164.62.255.25516,382
253164.63.0.0/18164.63.0.1 to 164.63.63.254164.63.63.25516,382
254164.63.64.0/18164.63.64.1 to 164.63.127.254164.63.127.25516,382
255164.63.128.0/18164.63.128.1 to 164.63.191.254164.63.191.25516,382
256164.63.192.0/18164.63.192.1 to 164.63.255.254164.63.255.25516,382

IPv4 CIDR reference (/0 to /32)

IPv4 prefix lengths
PrefixSubnet maskWildcardAddressesUsable hostsSizeTypical use
/00.0.0.0255.255.255.2554,294,967,2964,294,967,29416,777,216 × /24
/1128.0.0.0127.255.255.2552,147,483,6482,147,483,6468,388,608 × /24
/2192.0.0.063.255.255.2551,073,741,8241,073,741,8224,194,304 × /24
/3224.0.0.031.255.255.255536,870,912536,870,9102,097,152 × /24
/4240.0.0.015.255.255.255268,435,456268,435,4541,048,576 × /24
/5248.0.0.07.255.255.255134,217,728134,217,726524,288 × /24
/6252.0.0.03.255.255.25567,108,86467,108,862262,144 × /24
/7254.0.0.01.255.255.25533,554,43233,554,430131,072 × /24
/8255.0.0.00.255.255.25516,777,21616,777,21465,536 × /24Old class A; 10.0.0.0/8
/9255.128.0.00.127.255.2558,388,6088,388,60632,768 × /24
/10255.192.0.00.63.255.2554,194,3044,194,30216,384 × /24
/11255.224.0.00.31.255.2552,097,1522,097,1508,192 × /24
/12255.240.0.00.15.255.2551,048,5761,048,5744,096 × /24172.16.0.0/12
/13255.248.0.00.7.255.255524,288524,2862,048 × /24
/14255.252.0.00.3.255.255262,144262,1421,024 × /24
/15255.254.0.00.1.255.255131,072131,070512 × /24
/16255.255.0.00.0.255.25565,53665,534256 × /24Old class B; 192.168.0.0/16
/17255.255.128.00.0.127.25532,76832,766128 × /24
/18255.255.192.00.0.63.25516,38416,38264 × /24
/19255.255.224.00.0.31.2558,1928,19032 × /24
/20255.255.240.00.0.15.2554,0964,09416 × /24
/21255.255.248.00.0.7.2552,0482,0468 × /24
/22255.255.252.00.0.3.2551,0241,0224 × /24Large office or guest Wi-Fi (1,022 hosts)
/23255.255.254.00.0.1.2555125102 × /24Larger office LAN (510 hosts)
/24255.255.255.00.0.0.2552562541 × /24Typical office LAN (old class C)
/25255.255.255.1280.0.0.1271281261/2 of a /24Smaller LAN or VLAN
/26255.255.255.1920.0.0.6364621/4 of a /24Smaller LAN or VLAN
/27255.255.255.2240.0.0.3132301/8 of a /24Small VLAN, phones, cameras
/28255.255.255.2400.0.0.1516141/16 of a /24Small VLAN, phones, cameras
/29255.255.255.2480.0.0.7861/32 of a /24Small fixed public block (5 usable)
/30255.255.255.2520.0.0.3421/64 of a /24Point-to-point (old style)
/31255.255.255.2540.0.0.1221/128 of a /24Point-to-point link (RFC 3021)
/32255.255.255.2550.0.0.0111/256 of a /24One host

IPv6 prefix reference

IPv6 prefix lengths
PrefixAddresses/64 LANs/48 sitesNibbleTypical use
/342,535,295,865,117,307,932,921,825,928,971,026,432 (2^125)2,305,843,009,213,693,95235,184,372,088,832NoAll global unicast (2000::/3)
/165,192,296,858,534,827,628,530,496,329,220,096 (2^112)281,474,976,710,6564,294,967,296Yes
/20324,518,553,658,426,726,783,156,020,576,256 (2^108)17,592,186,044,416268,435,456YesLarge provider allocation (RIPE minimum for some)
/29633,825,300,114,114,700,748,351,602,688 (2^99)34,359,738,368524,288NoRIPE allocation to a provider (often)
/3279,228,162,514,264,337,593,543,950,336 (2^96)4,294,967,29665,536YesProvider allocation (RIPE default)
/364,951,760,157,141,521,099,596,496,896 (2^92)268,435,4564,096Yes
/40309,485,009,821,345,068,724,781,056 (2^88)16,777,216256Yes
/4419,342,813,113,834,066,795,298,816 (2^84)1,048,57616Yes
/481,208,925,819,614,629,174,706,176 (2^80)65,5361YesOne site or organisation (RIPE PI / assignment)
/5275,557,863,725,914,323,419,136 (2^76)4,096Yes
/564,722,366,482,869,645,213,696 (2^72)256YesSmall site or home (common provider assignment)
/60295,147,905,179,352,825,856 (2^68)16YesSome home broadband (16 LANs)
/6418,446,744,073,709,551,616 (2^64)1YesOne LAN or VLAN (needed for SLAAC)
/7272,057,594,037,927,936 (2^56)1/256 of a /64Yes
/80281,474,976,710,656 (2^48)1/65,536 of a /64Yes
/964,294,967,2961/4,294,967,296 of a /64YesEmbeds an IPv4 address (NAT64)
/11265,5361/281,474,976,710,656 of a /64Yes
/1202561/72,057,594,037,927,936 of a /64Yes
/124161/1,152,921,504,606,846,976 of a /64Yes
/12641/4,611,686,018,427,387,904 of a /64No
/12721/9,223,372,036,854,775,808 of a /64NoPoint-to-point link (RFC 6164)
/12811/18,446,744,073,709,551,616 of a /64YesOne host or loopback

Private and special ranges

IPv4

Special-purpose ranges
RangeNameWhat it is
255.255.255.255/32Limited broadcastEvery host on the local network
0.0.0.0/8This networkNot routed; 0.0.0.0 means "any address" in settings
10.0.0.0/8Private (RFC 1918)Office and home networks; not routed on the internet
100.64.0.0/10Shared address space (CGNAT)Used by providers behind carrier-grade NAT (RFC 6598)
127.0.0.0/8LoopbackThis computer
169.254.0.0/16Link-local (APIPA)Self-assigned when no DHCP server answers
172.16.0.0/12Private (RFC 1918)Office and home networks; not routed on the internet
192.0.0.0/24IETF protocol assignmentsSpecial uses such as DS-Lite
192.0.2.0/24Documentation (TEST-NET-1)For examples; never used on a network
192.88.99.0/246to4 relay (deprecated)Formerly anycast for 6to4
192.168.0.0/16Private (RFC 1918)Office and home networks; not routed on the internet
198.18.0.0/15BenchmarkingNetwork equipment testing (RFC 2544)
198.51.100.0/24Documentation (TEST-NET-2)For examples; never used on a network
203.0.113.0/24Documentation (TEST-NET-3)For examples; never used on a network
224.0.0.0/4MulticastOne-to-many traffic, such as IPTV and routing protocols
240.0.0.0/4ReservedFuture use; not usable on most systems

IPv6

Special-purpose ranges
RangeNameWhat it is
::/128UnspecifiedNo address; :: means "any address" in settings
::1/128LoopbackThis computer
::ffff:0:0/96IPv4-mappedAn IPv4 address written as IPv6
64:ff9b::/96NAT64IPv4 addresses reached through a NAT64 gateway
100::/64Discard onlyTraffic sent here is dropped (RFC 6666)
2001:db8::/32DocumentationFor examples; never used on a network
2001::/32TeredoIPv6 tunnelled over IPv4 UDP
2002::/166to4IPv6 tunnelled over IPv4 (largely retired)
3fff::/20DocumentationFor examples (RFC 9637)
fc00::/7Unique local (ULA)Private IPv6, like RFC 1918; usually fd00::/8
fe80::/10Link-localEvery IPv6 interface has one; not routed
ff00::/8MulticastOne-to-many traffic; replaces broadcast
2000::/3Global unicastPublic internet addresses

About this tool

A network is written as an address and a prefix length, such as 192.168.1.0/24: the first 24 bits name the network and the rest number the devices on it. The calculator works out where the network starts and ends, how many devices it holds, its subnet and wildcard masks, and the reverse DNS zone to ask your provider for.

It also splits a network into equal smaller ones (one per VLAN or site), turns a range of addresses into the fewest CIDR blocks for a firewall rule, and lists every IPv4 prefix length and the common IPv6 ones in reference tables.

Common questions

Why are two addresses lost in every IPv4 subnet?

The first address names the network and the last is the broadcast address, so a /24 has 256 addresses but 254 for devices. A /31 (a link between two routers) and a /32 (one host) are the exceptions.

What size of IPv6 network should a LAN use?

Always /64. Devices pick their own address within it (SLAAC), which needs the full 64 bits. A site usually gets a /48 or /56 from its provider, which holds 65,536 or 256 LANs.

What is a wildcard mask?

The subnet mask turned inside out: 255.255.255.0 becomes 0.0.0.255. Cisco access lists and OSPF use it to say which bits must match.

Which ranges can I use inside an office?

IPv4: 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16. IPv6: unique local addresses from fd00::/8, though most networks use the public prefix from their provider.