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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.

Network164.7.0.0/17
Usable hosts32,766
Subnet mask255.255.128.0
Addresses32,768
Network address
164.7.0.0
Broadcast address
164.7.127.255
First usable
164.7.0.1
Last usable
164.7.127.254
Usable hosts
32,766 (32,768 less the network and broadcast addresses)
Subnet mask
255.255.128.0
Wildcard mask
0.0.127.255 (Cisco ACLs, OSPF)
Prefix length
/17
Type
Public public
Old class
B (default /16)
As numbers
Hex A4070000 · Integer 2751922176 to 2751954943
Reverse DNS zones
0.7.164.in-addr.arpa
1.7.164.in-addr.arpa
2.7.164.in-addr.arpa
3.7.164.in-addr.arpa
4.7.164.in-addr.arpa
5.7.164.in-addr.arpa
6.7.164.in-addr.arpa
7.7.164.in-addr.arpa
8.7.164.in-addr.arpa
9.7.164.in-addr.arpa
10.7.164.in-addr.arpa
11.7.164.in-addr.arpa
12.7.164.in-addr.arpa
13.7.164.in-addr.arpa
14.7.164.in-addr.arpa
15.7.164.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
Address10100100.00000111.00000000.00000000164.7.0.0
Subnet mask11111111.11111111.10000000.00000000255.255.128.0
Network10100100.00000111.00000000.00000000164.7.0.0
Broadcast10100100.00000111.01111111.11111111164.7.127.255
Split into smaller subnets/28
/18 (2)/19 (4)/20 (8)/21 (16)/22 (32)/23 (64)/24 (128)/25 (256)/26 (512)/27 (1,024)/28 (2,048)/29 (4,096)

164.7.0.0/17 makes 2,048 subnets of /28; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1164.7.0.0/28164.7.0.1 to 164.7.0.14164.7.0.1514
2164.7.0.16/28164.7.0.17 to 164.7.0.30164.7.0.3114
3164.7.0.32/28164.7.0.33 to 164.7.0.46164.7.0.4714
4164.7.0.48/28164.7.0.49 to 164.7.0.62164.7.0.6314
5164.7.0.64/28164.7.0.65 to 164.7.0.78164.7.0.7914
6164.7.0.80/28164.7.0.81 to 164.7.0.94164.7.0.9514
7164.7.0.96/28164.7.0.97 to 164.7.0.110164.7.0.11114
8164.7.0.112/28164.7.0.113 to 164.7.0.126164.7.0.12714
9164.7.0.128/28164.7.0.129 to 164.7.0.142164.7.0.14314
10164.7.0.144/28164.7.0.145 to 164.7.0.158164.7.0.15914
11164.7.0.160/28164.7.0.161 to 164.7.0.174164.7.0.17514
12164.7.0.176/28164.7.0.177 to 164.7.0.190164.7.0.19114
13164.7.0.192/28164.7.0.193 to 164.7.0.206164.7.0.20714
14164.7.0.208/28164.7.0.209 to 164.7.0.222164.7.0.22314
15164.7.0.224/28164.7.0.225 to 164.7.0.238164.7.0.23914
16164.7.0.240/28164.7.0.241 to 164.7.0.254164.7.0.25514
17164.7.1.0/28164.7.1.1 to 164.7.1.14164.7.1.1514
18164.7.1.16/28164.7.1.17 to 164.7.1.30164.7.1.3114
19164.7.1.32/28164.7.1.33 to 164.7.1.46164.7.1.4714
20164.7.1.48/28164.7.1.49 to 164.7.1.62164.7.1.6314
21164.7.1.64/28164.7.1.65 to 164.7.1.78164.7.1.7914
22164.7.1.80/28164.7.1.81 to 164.7.1.94164.7.1.9514
23164.7.1.96/28164.7.1.97 to 164.7.1.110164.7.1.11114
24164.7.1.112/28164.7.1.113 to 164.7.1.126164.7.1.12714
25164.7.1.128/28164.7.1.129 to 164.7.1.142164.7.1.14314
26164.7.1.144/28164.7.1.145 to 164.7.1.158164.7.1.15914
27164.7.1.160/28164.7.1.161 to 164.7.1.174164.7.1.17514
28164.7.1.176/28164.7.1.177 to 164.7.1.190164.7.1.19114
29164.7.1.192/28164.7.1.193 to 164.7.1.206164.7.1.20714
30164.7.1.208/28164.7.1.209 to 164.7.1.222164.7.1.22314
31164.7.1.224/28164.7.1.225 to 164.7.1.238164.7.1.23914
32164.7.1.240/28164.7.1.241 to 164.7.1.254164.7.1.25514
33164.7.2.0/28164.7.2.1 to 164.7.2.14164.7.2.1514
34164.7.2.16/28164.7.2.17 to 164.7.2.30164.7.2.3114
35164.7.2.32/28164.7.2.33 to 164.7.2.46164.7.2.4714
36164.7.2.48/28164.7.2.49 to 164.7.2.62164.7.2.6314
37164.7.2.64/28164.7.2.65 to 164.7.2.78164.7.2.7914
38164.7.2.80/28164.7.2.81 to 164.7.2.94164.7.2.9514
39164.7.2.96/28164.7.2.97 to 164.7.2.110164.7.2.11114
40164.7.2.112/28164.7.2.113 to 164.7.2.126164.7.2.12714
41164.7.2.128/28164.7.2.129 to 164.7.2.142164.7.2.14314
42164.7.2.144/28164.7.2.145 to 164.7.2.158164.7.2.15914
43164.7.2.160/28164.7.2.161 to 164.7.2.174164.7.2.17514
44164.7.2.176/28164.7.2.177 to 164.7.2.190164.7.2.19114
45164.7.2.192/28164.7.2.193 to 164.7.2.206164.7.2.20714
46164.7.2.208/28164.7.2.209 to 164.7.2.222164.7.2.22314
47164.7.2.224/28164.7.2.225 to 164.7.2.238164.7.2.23914
48164.7.2.240/28164.7.2.241 to 164.7.2.254164.7.2.25514
49164.7.3.0/28164.7.3.1 to 164.7.3.14164.7.3.1514
50164.7.3.16/28164.7.3.17 to 164.7.3.30164.7.3.3114
51164.7.3.32/28164.7.3.33 to 164.7.3.46164.7.3.4714
52164.7.3.48/28164.7.3.49 to 164.7.3.62164.7.3.6314
53164.7.3.64/28164.7.3.65 to 164.7.3.78164.7.3.7914
54164.7.3.80/28164.7.3.81 to 164.7.3.94164.7.3.9514
55164.7.3.96/28164.7.3.97 to 164.7.3.110164.7.3.11114
56164.7.3.112/28164.7.3.113 to 164.7.3.126164.7.3.12714
57164.7.3.128/28164.7.3.129 to 164.7.3.142164.7.3.14314
58164.7.3.144/28164.7.3.145 to 164.7.3.158164.7.3.15914
59164.7.3.160/28164.7.3.161 to 164.7.3.174164.7.3.17514
60164.7.3.176/28164.7.3.177 to 164.7.3.190164.7.3.19114
61164.7.3.192/28164.7.3.193 to 164.7.3.206164.7.3.20714
62164.7.3.208/28164.7.3.209 to 164.7.3.222164.7.3.22314
63164.7.3.224/28164.7.3.225 to 164.7.3.238164.7.3.23914
64164.7.3.240/28164.7.3.241 to 164.7.3.254164.7.3.25514
65164.7.4.0/28164.7.4.1 to 164.7.4.14164.7.4.1514
66164.7.4.16/28164.7.4.17 to 164.7.4.30164.7.4.3114
67164.7.4.32/28164.7.4.33 to 164.7.4.46164.7.4.4714
68164.7.4.48/28164.7.4.49 to 164.7.4.62164.7.4.6314
69164.7.4.64/28164.7.4.65 to 164.7.4.78164.7.4.7914
70164.7.4.80/28164.7.4.81 to 164.7.4.94164.7.4.9514
71164.7.4.96/28164.7.4.97 to 164.7.4.110164.7.4.11114
72164.7.4.112/28164.7.4.113 to 164.7.4.126164.7.4.12714
73164.7.4.128/28164.7.4.129 to 164.7.4.142164.7.4.14314
74164.7.4.144/28164.7.4.145 to 164.7.4.158164.7.4.15914
75164.7.4.160/28164.7.4.161 to 164.7.4.174164.7.4.17514
76164.7.4.176/28164.7.4.177 to 164.7.4.190164.7.4.19114
77164.7.4.192/28164.7.4.193 to 164.7.4.206164.7.4.20714
78164.7.4.208/28164.7.4.209 to 164.7.4.222164.7.4.22314
79164.7.4.224/28164.7.4.225 to 164.7.4.238164.7.4.23914
80164.7.4.240/28164.7.4.241 to 164.7.4.254164.7.4.25514
81164.7.5.0/28164.7.5.1 to 164.7.5.14164.7.5.1514
82164.7.5.16/28164.7.5.17 to 164.7.5.30164.7.5.3114
83164.7.5.32/28164.7.5.33 to 164.7.5.46164.7.5.4714
84164.7.5.48/28164.7.5.49 to 164.7.5.62164.7.5.6314
85164.7.5.64/28164.7.5.65 to 164.7.5.78164.7.5.7914
86164.7.5.80/28164.7.5.81 to 164.7.5.94164.7.5.9514
87164.7.5.96/28164.7.5.97 to 164.7.5.110164.7.5.11114
88164.7.5.112/28164.7.5.113 to 164.7.5.126164.7.5.12714
89164.7.5.128/28164.7.5.129 to 164.7.5.142164.7.5.14314
90164.7.5.144/28164.7.5.145 to 164.7.5.158164.7.5.15914
91164.7.5.160/28164.7.5.161 to 164.7.5.174164.7.5.17514
92164.7.5.176/28164.7.5.177 to 164.7.5.190164.7.5.19114
93164.7.5.192/28164.7.5.193 to 164.7.5.206164.7.5.20714
94164.7.5.208/28164.7.5.209 to 164.7.5.222164.7.5.22314
95164.7.5.224/28164.7.5.225 to 164.7.5.238164.7.5.23914
96164.7.5.240/28164.7.5.241 to 164.7.5.254164.7.5.25514
97164.7.6.0/28164.7.6.1 to 164.7.6.14164.7.6.1514
98164.7.6.16/28164.7.6.17 to 164.7.6.30164.7.6.3114
99164.7.6.32/28164.7.6.33 to 164.7.6.46164.7.6.4714
100164.7.6.48/28164.7.6.49 to 164.7.6.62164.7.6.6314
101164.7.6.64/28164.7.6.65 to 164.7.6.78164.7.6.7914
102164.7.6.80/28164.7.6.81 to 164.7.6.94164.7.6.9514
103164.7.6.96/28164.7.6.97 to 164.7.6.110164.7.6.11114
104164.7.6.112/28164.7.6.113 to 164.7.6.126164.7.6.12714
105164.7.6.128/28164.7.6.129 to 164.7.6.142164.7.6.14314
106164.7.6.144/28164.7.6.145 to 164.7.6.158164.7.6.15914
107164.7.6.160/28164.7.6.161 to 164.7.6.174164.7.6.17514
108164.7.6.176/28164.7.6.177 to 164.7.6.190164.7.6.19114
109164.7.6.192/28164.7.6.193 to 164.7.6.206164.7.6.20714
110164.7.6.208/28164.7.6.209 to 164.7.6.222164.7.6.22314
111164.7.6.224/28164.7.6.225 to 164.7.6.238164.7.6.23914
112164.7.6.240/28164.7.6.241 to 164.7.6.254164.7.6.25514
113164.7.7.0/28164.7.7.1 to 164.7.7.14164.7.7.1514
114164.7.7.16/28164.7.7.17 to 164.7.7.30164.7.7.3114
115164.7.7.32/28164.7.7.33 to 164.7.7.46164.7.7.4714
116164.7.7.48/28164.7.7.49 to 164.7.7.62164.7.7.6314
117164.7.7.64/28164.7.7.65 to 164.7.7.78164.7.7.7914
118164.7.7.80/28164.7.7.81 to 164.7.7.94164.7.7.9514
119164.7.7.96/28164.7.7.97 to 164.7.7.110164.7.7.11114
120164.7.7.112/28164.7.7.113 to 164.7.7.126164.7.7.12714
121164.7.7.128/28164.7.7.129 to 164.7.7.142164.7.7.14314
122164.7.7.144/28164.7.7.145 to 164.7.7.158164.7.7.15914
123164.7.7.160/28164.7.7.161 to 164.7.7.174164.7.7.17514
124164.7.7.176/28164.7.7.177 to 164.7.7.190164.7.7.19114
125164.7.7.192/28164.7.7.193 to 164.7.7.206164.7.7.20714
126164.7.7.208/28164.7.7.209 to 164.7.7.222164.7.7.22314
127164.7.7.224/28164.7.7.225 to 164.7.7.238164.7.7.23914
128164.7.7.240/28164.7.7.241 to 164.7.7.254164.7.7.25514
129164.7.8.0/28164.7.8.1 to 164.7.8.14164.7.8.1514
130164.7.8.16/28164.7.8.17 to 164.7.8.30164.7.8.3114
131164.7.8.32/28164.7.8.33 to 164.7.8.46164.7.8.4714
132164.7.8.48/28164.7.8.49 to 164.7.8.62164.7.8.6314
133164.7.8.64/28164.7.8.65 to 164.7.8.78164.7.8.7914
134164.7.8.80/28164.7.8.81 to 164.7.8.94164.7.8.9514
135164.7.8.96/28164.7.8.97 to 164.7.8.110164.7.8.11114
136164.7.8.112/28164.7.8.113 to 164.7.8.126164.7.8.12714
137164.7.8.128/28164.7.8.129 to 164.7.8.142164.7.8.14314
138164.7.8.144/28164.7.8.145 to 164.7.8.158164.7.8.15914
139164.7.8.160/28164.7.8.161 to 164.7.8.174164.7.8.17514
140164.7.8.176/28164.7.8.177 to 164.7.8.190164.7.8.19114
141164.7.8.192/28164.7.8.193 to 164.7.8.206164.7.8.20714
142164.7.8.208/28164.7.8.209 to 164.7.8.222164.7.8.22314
143164.7.8.224/28164.7.8.225 to 164.7.8.238164.7.8.23914
144164.7.8.240/28164.7.8.241 to 164.7.8.254164.7.8.25514
145164.7.9.0/28164.7.9.1 to 164.7.9.14164.7.9.1514
146164.7.9.16/28164.7.9.17 to 164.7.9.30164.7.9.3114
147164.7.9.32/28164.7.9.33 to 164.7.9.46164.7.9.4714
148164.7.9.48/28164.7.9.49 to 164.7.9.62164.7.9.6314
149164.7.9.64/28164.7.9.65 to 164.7.9.78164.7.9.7914
150164.7.9.80/28164.7.9.81 to 164.7.9.94164.7.9.9514
151164.7.9.96/28164.7.9.97 to 164.7.9.110164.7.9.11114
152164.7.9.112/28164.7.9.113 to 164.7.9.126164.7.9.12714
153164.7.9.128/28164.7.9.129 to 164.7.9.142164.7.9.14314
154164.7.9.144/28164.7.9.145 to 164.7.9.158164.7.9.15914
155164.7.9.160/28164.7.9.161 to 164.7.9.174164.7.9.17514
156164.7.9.176/28164.7.9.177 to 164.7.9.190164.7.9.19114
157164.7.9.192/28164.7.9.193 to 164.7.9.206164.7.9.20714
158164.7.9.208/28164.7.9.209 to 164.7.9.222164.7.9.22314
159164.7.9.224/28164.7.9.225 to 164.7.9.238164.7.9.23914
160164.7.9.240/28164.7.9.241 to 164.7.9.254164.7.9.25514
161164.7.10.0/28164.7.10.1 to 164.7.10.14164.7.10.1514
162164.7.10.16/28164.7.10.17 to 164.7.10.30164.7.10.3114
163164.7.10.32/28164.7.10.33 to 164.7.10.46164.7.10.4714
164164.7.10.48/28164.7.10.49 to 164.7.10.62164.7.10.6314
165164.7.10.64/28164.7.10.65 to 164.7.10.78164.7.10.7914
166164.7.10.80/28164.7.10.81 to 164.7.10.94164.7.10.9514
167164.7.10.96/28164.7.10.97 to 164.7.10.110164.7.10.11114
168164.7.10.112/28164.7.10.113 to 164.7.10.126164.7.10.12714
169164.7.10.128/28164.7.10.129 to 164.7.10.142164.7.10.14314
170164.7.10.144/28164.7.10.145 to 164.7.10.158164.7.10.15914
171164.7.10.160/28164.7.10.161 to 164.7.10.174164.7.10.17514
172164.7.10.176/28164.7.10.177 to 164.7.10.190164.7.10.19114
173164.7.10.192/28164.7.10.193 to 164.7.10.206164.7.10.20714
174164.7.10.208/28164.7.10.209 to 164.7.10.222164.7.10.22314
175164.7.10.224/28164.7.10.225 to 164.7.10.238164.7.10.23914
176164.7.10.240/28164.7.10.241 to 164.7.10.254164.7.10.25514
177164.7.11.0/28164.7.11.1 to 164.7.11.14164.7.11.1514
178164.7.11.16/28164.7.11.17 to 164.7.11.30164.7.11.3114
179164.7.11.32/28164.7.11.33 to 164.7.11.46164.7.11.4714
180164.7.11.48/28164.7.11.49 to 164.7.11.62164.7.11.6314
181164.7.11.64/28164.7.11.65 to 164.7.11.78164.7.11.7914
182164.7.11.80/28164.7.11.81 to 164.7.11.94164.7.11.9514
183164.7.11.96/28164.7.11.97 to 164.7.11.110164.7.11.11114
184164.7.11.112/28164.7.11.113 to 164.7.11.126164.7.11.12714
185164.7.11.128/28164.7.11.129 to 164.7.11.142164.7.11.14314
186164.7.11.144/28164.7.11.145 to 164.7.11.158164.7.11.15914
187164.7.11.160/28164.7.11.161 to 164.7.11.174164.7.11.17514
188164.7.11.176/28164.7.11.177 to 164.7.11.190164.7.11.19114
189164.7.11.192/28164.7.11.193 to 164.7.11.206164.7.11.20714
190164.7.11.208/28164.7.11.209 to 164.7.11.222164.7.11.22314
191164.7.11.224/28164.7.11.225 to 164.7.11.238164.7.11.23914
192164.7.11.240/28164.7.11.241 to 164.7.11.254164.7.11.25514
193164.7.12.0/28164.7.12.1 to 164.7.12.14164.7.12.1514
194164.7.12.16/28164.7.12.17 to 164.7.12.30164.7.12.3114
195164.7.12.32/28164.7.12.33 to 164.7.12.46164.7.12.4714
196164.7.12.48/28164.7.12.49 to 164.7.12.62164.7.12.6314
197164.7.12.64/28164.7.12.65 to 164.7.12.78164.7.12.7914
198164.7.12.80/28164.7.12.81 to 164.7.12.94164.7.12.9514
199164.7.12.96/28164.7.12.97 to 164.7.12.110164.7.12.11114
200164.7.12.112/28164.7.12.113 to 164.7.12.126164.7.12.12714
201164.7.12.128/28164.7.12.129 to 164.7.12.142164.7.12.14314
202164.7.12.144/28164.7.12.145 to 164.7.12.158164.7.12.15914
203164.7.12.160/28164.7.12.161 to 164.7.12.174164.7.12.17514
204164.7.12.176/28164.7.12.177 to 164.7.12.190164.7.12.19114
205164.7.12.192/28164.7.12.193 to 164.7.12.206164.7.12.20714
206164.7.12.208/28164.7.12.209 to 164.7.12.222164.7.12.22314
207164.7.12.224/28164.7.12.225 to 164.7.12.238164.7.12.23914
208164.7.12.240/28164.7.12.241 to 164.7.12.254164.7.12.25514
209164.7.13.0/28164.7.13.1 to 164.7.13.14164.7.13.1514
210164.7.13.16/28164.7.13.17 to 164.7.13.30164.7.13.3114
211164.7.13.32/28164.7.13.33 to 164.7.13.46164.7.13.4714
212164.7.13.48/28164.7.13.49 to 164.7.13.62164.7.13.6314
213164.7.13.64/28164.7.13.65 to 164.7.13.78164.7.13.7914
214164.7.13.80/28164.7.13.81 to 164.7.13.94164.7.13.9514
215164.7.13.96/28164.7.13.97 to 164.7.13.110164.7.13.11114
216164.7.13.112/28164.7.13.113 to 164.7.13.126164.7.13.12714
217164.7.13.128/28164.7.13.129 to 164.7.13.142164.7.13.14314
218164.7.13.144/28164.7.13.145 to 164.7.13.158164.7.13.15914
219164.7.13.160/28164.7.13.161 to 164.7.13.174164.7.13.17514
220164.7.13.176/28164.7.13.177 to 164.7.13.190164.7.13.19114
221164.7.13.192/28164.7.13.193 to 164.7.13.206164.7.13.20714
222164.7.13.208/28164.7.13.209 to 164.7.13.222164.7.13.22314
223164.7.13.224/28164.7.13.225 to 164.7.13.238164.7.13.23914
224164.7.13.240/28164.7.13.241 to 164.7.13.254164.7.13.25514
225164.7.14.0/28164.7.14.1 to 164.7.14.14164.7.14.1514
226164.7.14.16/28164.7.14.17 to 164.7.14.30164.7.14.3114
227164.7.14.32/28164.7.14.33 to 164.7.14.46164.7.14.4714
228164.7.14.48/28164.7.14.49 to 164.7.14.62164.7.14.6314
229164.7.14.64/28164.7.14.65 to 164.7.14.78164.7.14.7914
230164.7.14.80/28164.7.14.81 to 164.7.14.94164.7.14.9514
231164.7.14.96/28164.7.14.97 to 164.7.14.110164.7.14.11114
232164.7.14.112/28164.7.14.113 to 164.7.14.126164.7.14.12714
233164.7.14.128/28164.7.14.129 to 164.7.14.142164.7.14.14314
234164.7.14.144/28164.7.14.145 to 164.7.14.158164.7.14.15914
235164.7.14.160/28164.7.14.161 to 164.7.14.174164.7.14.17514
236164.7.14.176/28164.7.14.177 to 164.7.14.190164.7.14.19114
237164.7.14.192/28164.7.14.193 to 164.7.14.206164.7.14.20714
238164.7.14.208/28164.7.14.209 to 164.7.14.222164.7.14.22314
239164.7.14.224/28164.7.14.225 to 164.7.14.238164.7.14.23914
240164.7.14.240/28164.7.14.241 to 164.7.14.254164.7.14.25514
241164.7.15.0/28164.7.15.1 to 164.7.15.14164.7.15.1514
242164.7.15.16/28164.7.15.17 to 164.7.15.30164.7.15.3114
243164.7.15.32/28164.7.15.33 to 164.7.15.46164.7.15.4714
244164.7.15.48/28164.7.15.49 to 164.7.15.62164.7.15.6314
245164.7.15.64/28164.7.15.65 to 164.7.15.78164.7.15.7914
246164.7.15.80/28164.7.15.81 to 164.7.15.94164.7.15.9514
247164.7.15.96/28164.7.15.97 to 164.7.15.110164.7.15.11114
248164.7.15.112/28164.7.15.113 to 164.7.15.126164.7.15.12714
249164.7.15.128/28164.7.15.129 to 164.7.15.142164.7.15.14314
250164.7.15.144/28164.7.15.145 to 164.7.15.158164.7.15.15914
251164.7.15.160/28164.7.15.161 to 164.7.15.174164.7.15.17514
252164.7.15.176/28164.7.15.177 to 164.7.15.190164.7.15.19114
253164.7.15.192/28164.7.15.193 to 164.7.15.206164.7.15.20714
254164.7.15.208/28164.7.15.209 to 164.7.15.222164.7.15.22314
255164.7.15.224/28164.7.15.225 to 164.7.15.238164.7.15.23914
256164.7.15.240/28164.7.15.241 to 164.7.15.254164.7.15.25514

IPv4 CIDR reference (/0 to /32)

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

IPv6 prefix reference

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

Private and special ranges

IPv4

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

IPv6

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

About this tool

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

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

Common questions

Why are two addresses lost in every IPv4 subnet?

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

What size of IPv6 network should a LAN use?

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

What is a wildcard mask?

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

Which ranges can I use inside an office?

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