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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.

Network164.0.0.0/10
Usable hosts4,194,302
Subnet mask255.192.0.0
Addresses4,194,304
Network address
164.0.0.0
Broadcast address
164.63.255.255
First usable
164.0.0.1
Last usable
164.63.255.254
Usable hosts
4,194,302 (4,194,304 less the network and broadcast addresses)
Subnet mask
255.192.0.0
Wildcard mask
0.63.255.255 (Cisco ACLs, OSPF)
Prefix length
/10
Type
Public public
Old class
B (default /16)
As numbers
Hex A4000000 · Integer 2751463424 to 2755657727
Reverse DNS zones
0.164.in-addr.arpa
1.164.in-addr.arpa
2.164.in-addr.arpa
3.164.in-addr.arpa
4.164.in-addr.arpa
5.164.in-addr.arpa
6.164.in-addr.arpa
7.164.in-addr.arpa
8.164.in-addr.arpa
9.164.in-addr.arpa
10.164.in-addr.arpa
11.164.in-addr.arpa
12.164.in-addr.arpa
13.164.in-addr.arpa
14.164.in-addr.arpa
15.164.in-addr.arpa
and 48 more
/10 is not on a 8-bit boundary, so it takes 64 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10100100.00000000.00000000.00000000164.0.0.0
Subnet mask11111111.11000000.00000000.00000000255.192.0.0
Network10100100.00000000.00000000.00000000164.0.0.0
Broadcast10100100.00111111.11111111.11111111164.63.255.255
Split into smaller subnets/20
/11 (2)/12 (4)/13 (8)/14 (16)/15 (32)/16 (64)/17 (128)/18 (256)/19 (512)/20 (1,024)/21 (2,048)/22 (4,096)

164.0.0.0/10 makes 1,024 subnets of /20; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1164.0.0.0/20164.0.0.1 to 164.0.15.254164.0.15.2554,094
2164.0.16.0/20164.0.16.1 to 164.0.31.254164.0.31.2554,094
3164.0.32.0/20164.0.32.1 to 164.0.47.254164.0.47.2554,094
4164.0.48.0/20164.0.48.1 to 164.0.63.254164.0.63.2554,094
5164.0.64.0/20164.0.64.1 to 164.0.79.254164.0.79.2554,094
6164.0.80.0/20164.0.80.1 to 164.0.95.254164.0.95.2554,094
7164.0.96.0/20164.0.96.1 to 164.0.111.254164.0.111.2554,094
8164.0.112.0/20164.0.112.1 to 164.0.127.254164.0.127.2554,094
9164.0.128.0/20164.0.128.1 to 164.0.143.254164.0.143.2554,094
10164.0.144.0/20164.0.144.1 to 164.0.159.254164.0.159.2554,094
11164.0.160.0/20164.0.160.1 to 164.0.175.254164.0.175.2554,094
12164.0.176.0/20164.0.176.1 to 164.0.191.254164.0.191.2554,094
13164.0.192.0/20164.0.192.1 to 164.0.207.254164.0.207.2554,094
14164.0.208.0/20164.0.208.1 to 164.0.223.254164.0.223.2554,094
15164.0.224.0/20164.0.224.1 to 164.0.239.254164.0.239.2554,094
16164.0.240.0/20164.0.240.1 to 164.0.255.254164.0.255.2554,094
17164.1.0.0/20164.1.0.1 to 164.1.15.254164.1.15.2554,094
18164.1.16.0/20164.1.16.1 to 164.1.31.254164.1.31.2554,094
19164.1.32.0/20164.1.32.1 to 164.1.47.254164.1.47.2554,094
20164.1.48.0/20164.1.48.1 to 164.1.63.254164.1.63.2554,094
21164.1.64.0/20164.1.64.1 to 164.1.79.254164.1.79.2554,094
22164.1.80.0/20164.1.80.1 to 164.1.95.254164.1.95.2554,094
23164.1.96.0/20164.1.96.1 to 164.1.111.254164.1.111.2554,094
24164.1.112.0/20164.1.112.1 to 164.1.127.254164.1.127.2554,094
25164.1.128.0/20164.1.128.1 to 164.1.143.254164.1.143.2554,094
26164.1.144.0/20164.1.144.1 to 164.1.159.254164.1.159.2554,094
27164.1.160.0/20164.1.160.1 to 164.1.175.254164.1.175.2554,094
28164.1.176.0/20164.1.176.1 to 164.1.191.254164.1.191.2554,094
29164.1.192.0/20164.1.192.1 to 164.1.207.254164.1.207.2554,094
30164.1.208.0/20164.1.208.1 to 164.1.223.254164.1.223.2554,094
31164.1.224.0/20164.1.224.1 to 164.1.239.254164.1.239.2554,094
32164.1.240.0/20164.1.240.1 to 164.1.255.254164.1.255.2554,094
33164.2.0.0/20164.2.0.1 to 164.2.15.254164.2.15.2554,094
34164.2.16.0/20164.2.16.1 to 164.2.31.254164.2.31.2554,094
35164.2.32.0/20164.2.32.1 to 164.2.47.254164.2.47.2554,094
36164.2.48.0/20164.2.48.1 to 164.2.63.254164.2.63.2554,094
37164.2.64.0/20164.2.64.1 to 164.2.79.254164.2.79.2554,094
38164.2.80.0/20164.2.80.1 to 164.2.95.254164.2.95.2554,094
39164.2.96.0/20164.2.96.1 to 164.2.111.254164.2.111.2554,094
40164.2.112.0/20164.2.112.1 to 164.2.127.254164.2.127.2554,094
41164.2.128.0/20164.2.128.1 to 164.2.143.254164.2.143.2554,094
42164.2.144.0/20164.2.144.1 to 164.2.159.254164.2.159.2554,094
43164.2.160.0/20164.2.160.1 to 164.2.175.254164.2.175.2554,094
44164.2.176.0/20164.2.176.1 to 164.2.191.254164.2.191.2554,094
45164.2.192.0/20164.2.192.1 to 164.2.207.254164.2.207.2554,094
46164.2.208.0/20164.2.208.1 to 164.2.223.254164.2.223.2554,094
47164.2.224.0/20164.2.224.1 to 164.2.239.254164.2.239.2554,094
48164.2.240.0/20164.2.240.1 to 164.2.255.254164.2.255.2554,094
49164.3.0.0/20164.3.0.1 to 164.3.15.254164.3.15.2554,094
50164.3.16.0/20164.3.16.1 to 164.3.31.254164.3.31.2554,094
51164.3.32.0/20164.3.32.1 to 164.3.47.254164.3.47.2554,094
52164.3.48.0/20164.3.48.1 to 164.3.63.254164.3.63.2554,094
53164.3.64.0/20164.3.64.1 to 164.3.79.254164.3.79.2554,094
54164.3.80.0/20164.3.80.1 to 164.3.95.254164.3.95.2554,094
55164.3.96.0/20164.3.96.1 to 164.3.111.254164.3.111.2554,094
56164.3.112.0/20164.3.112.1 to 164.3.127.254164.3.127.2554,094
57164.3.128.0/20164.3.128.1 to 164.3.143.254164.3.143.2554,094
58164.3.144.0/20164.3.144.1 to 164.3.159.254164.3.159.2554,094
59164.3.160.0/20164.3.160.1 to 164.3.175.254164.3.175.2554,094
60164.3.176.0/20164.3.176.1 to 164.3.191.254164.3.191.2554,094
61164.3.192.0/20164.3.192.1 to 164.3.207.254164.3.207.2554,094
62164.3.208.0/20164.3.208.1 to 164.3.223.254164.3.223.2554,094
63164.3.224.0/20164.3.224.1 to 164.3.239.254164.3.239.2554,094
64164.3.240.0/20164.3.240.1 to 164.3.255.254164.3.255.2554,094
65164.4.0.0/20164.4.0.1 to 164.4.15.254164.4.15.2554,094
66164.4.16.0/20164.4.16.1 to 164.4.31.254164.4.31.2554,094
67164.4.32.0/20164.4.32.1 to 164.4.47.254164.4.47.2554,094
68164.4.48.0/20164.4.48.1 to 164.4.63.254164.4.63.2554,094
69164.4.64.0/20164.4.64.1 to 164.4.79.254164.4.79.2554,094
70164.4.80.0/20164.4.80.1 to 164.4.95.254164.4.95.2554,094
71164.4.96.0/20164.4.96.1 to 164.4.111.254164.4.111.2554,094
72164.4.112.0/20164.4.112.1 to 164.4.127.254164.4.127.2554,094
73164.4.128.0/20164.4.128.1 to 164.4.143.254164.4.143.2554,094
74164.4.144.0/20164.4.144.1 to 164.4.159.254164.4.159.2554,094
75164.4.160.0/20164.4.160.1 to 164.4.175.254164.4.175.2554,094
76164.4.176.0/20164.4.176.1 to 164.4.191.254164.4.191.2554,094
77164.4.192.0/20164.4.192.1 to 164.4.207.254164.4.207.2554,094
78164.4.208.0/20164.4.208.1 to 164.4.223.254164.4.223.2554,094
79164.4.224.0/20164.4.224.1 to 164.4.239.254164.4.239.2554,094
80164.4.240.0/20164.4.240.1 to 164.4.255.254164.4.255.2554,094
81164.5.0.0/20164.5.0.1 to 164.5.15.254164.5.15.2554,094
82164.5.16.0/20164.5.16.1 to 164.5.31.254164.5.31.2554,094
83164.5.32.0/20164.5.32.1 to 164.5.47.254164.5.47.2554,094
84164.5.48.0/20164.5.48.1 to 164.5.63.254164.5.63.2554,094
85164.5.64.0/20164.5.64.1 to 164.5.79.254164.5.79.2554,094
86164.5.80.0/20164.5.80.1 to 164.5.95.254164.5.95.2554,094
87164.5.96.0/20164.5.96.1 to 164.5.111.254164.5.111.2554,094
88164.5.112.0/20164.5.112.1 to 164.5.127.254164.5.127.2554,094
89164.5.128.0/20164.5.128.1 to 164.5.143.254164.5.143.2554,094
90164.5.144.0/20164.5.144.1 to 164.5.159.254164.5.159.2554,094
91164.5.160.0/20164.5.160.1 to 164.5.175.254164.5.175.2554,094
92164.5.176.0/20164.5.176.1 to 164.5.191.254164.5.191.2554,094
93164.5.192.0/20164.5.192.1 to 164.5.207.254164.5.207.2554,094
94164.5.208.0/20164.5.208.1 to 164.5.223.254164.5.223.2554,094
95164.5.224.0/20164.5.224.1 to 164.5.239.254164.5.239.2554,094
96164.5.240.0/20164.5.240.1 to 164.5.255.254164.5.255.2554,094
97164.6.0.0/20164.6.0.1 to 164.6.15.254164.6.15.2554,094
98164.6.16.0/20164.6.16.1 to 164.6.31.254164.6.31.2554,094
99164.6.32.0/20164.6.32.1 to 164.6.47.254164.6.47.2554,094
100164.6.48.0/20164.6.48.1 to 164.6.63.254164.6.63.2554,094
101164.6.64.0/20164.6.64.1 to 164.6.79.254164.6.79.2554,094
102164.6.80.0/20164.6.80.1 to 164.6.95.254164.6.95.2554,094
103164.6.96.0/20164.6.96.1 to 164.6.111.254164.6.111.2554,094
104164.6.112.0/20164.6.112.1 to 164.6.127.254164.6.127.2554,094
105164.6.128.0/20164.6.128.1 to 164.6.143.254164.6.143.2554,094
106164.6.144.0/20164.6.144.1 to 164.6.159.254164.6.159.2554,094
107164.6.160.0/20164.6.160.1 to 164.6.175.254164.6.175.2554,094
108164.6.176.0/20164.6.176.1 to 164.6.191.254164.6.191.2554,094
109164.6.192.0/20164.6.192.1 to 164.6.207.254164.6.207.2554,094
110164.6.208.0/20164.6.208.1 to 164.6.223.254164.6.223.2554,094
111164.6.224.0/20164.6.224.1 to 164.6.239.254164.6.239.2554,094
112164.6.240.0/20164.6.240.1 to 164.6.255.254164.6.255.2554,094
113164.7.0.0/20164.7.0.1 to 164.7.15.254164.7.15.2554,094
114164.7.16.0/20164.7.16.1 to 164.7.31.254164.7.31.2554,094
115164.7.32.0/20164.7.32.1 to 164.7.47.254164.7.47.2554,094
116164.7.48.0/20164.7.48.1 to 164.7.63.254164.7.63.2554,094
117164.7.64.0/20164.7.64.1 to 164.7.79.254164.7.79.2554,094
118164.7.80.0/20164.7.80.1 to 164.7.95.254164.7.95.2554,094
119164.7.96.0/20164.7.96.1 to 164.7.111.254164.7.111.2554,094
120164.7.112.0/20164.7.112.1 to 164.7.127.254164.7.127.2554,094
121164.7.128.0/20164.7.128.1 to 164.7.143.254164.7.143.2554,094
122164.7.144.0/20164.7.144.1 to 164.7.159.254164.7.159.2554,094
123164.7.160.0/20164.7.160.1 to 164.7.175.254164.7.175.2554,094
124164.7.176.0/20164.7.176.1 to 164.7.191.254164.7.191.2554,094
125164.7.192.0/20164.7.192.1 to 164.7.207.254164.7.207.2554,094
126164.7.208.0/20164.7.208.1 to 164.7.223.254164.7.223.2554,094
127164.7.224.0/20164.7.224.1 to 164.7.239.254164.7.239.2554,094
128164.7.240.0/20164.7.240.1 to 164.7.255.254164.7.255.2554,094
129164.8.0.0/20164.8.0.1 to 164.8.15.254164.8.15.2554,094
130164.8.16.0/20164.8.16.1 to 164.8.31.254164.8.31.2554,094
131164.8.32.0/20164.8.32.1 to 164.8.47.254164.8.47.2554,094
132164.8.48.0/20164.8.48.1 to 164.8.63.254164.8.63.2554,094
133164.8.64.0/20164.8.64.1 to 164.8.79.254164.8.79.2554,094
134164.8.80.0/20164.8.80.1 to 164.8.95.254164.8.95.2554,094
135164.8.96.0/20164.8.96.1 to 164.8.111.254164.8.111.2554,094
136164.8.112.0/20164.8.112.1 to 164.8.127.254164.8.127.2554,094
137164.8.128.0/20164.8.128.1 to 164.8.143.254164.8.143.2554,094
138164.8.144.0/20164.8.144.1 to 164.8.159.254164.8.159.2554,094
139164.8.160.0/20164.8.160.1 to 164.8.175.254164.8.175.2554,094
140164.8.176.0/20164.8.176.1 to 164.8.191.254164.8.191.2554,094
141164.8.192.0/20164.8.192.1 to 164.8.207.254164.8.207.2554,094
142164.8.208.0/20164.8.208.1 to 164.8.223.254164.8.223.2554,094
143164.8.224.0/20164.8.224.1 to 164.8.239.254164.8.239.2554,094
144164.8.240.0/20164.8.240.1 to 164.8.255.254164.8.255.2554,094
145164.9.0.0/20164.9.0.1 to 164.9.15.254164.9.15.2554,094
146164.9.16.0/20164.9.16.1 to 164.9.31.254164.9.31.2554,094
147164.9.32.0/20164.9.32.1 to 164.9.47.254164.9.47.2554,094
148164.9.48.0/20164.9.48.1 to 164.9.63.254164.9.63.2554,094
149164.9.64.0/20164.9.64.1 to 164.9.79.254164.9.79.2554,094
150164.9.80.0/20164.9.80.1 to 164.9.95.254164.9.95.2554,094
151164.9.96.0/20164.9.96.1 to 164.9.111.254164.9.111.2554,094
152164.9.112.0/20164.9.112.1 to 164.9.127.254164.9.127.2554,094
153164.9.128.0/20164.9.128.1 to 164.9.143.254164.9.143.2554,094
154164.9.144.0/20164.9.144.1 to 164.9.159.254164.9.159.2554,094
155164.9.160.0/20164.9.160.1 to 164.9.175.254164.9.175.2554,094
156164.9.176.0/20164.9.176.1 to 164.9.191.254164.9.191.2554,094
157164.9.192.0/20164.9.192.1 to 164.9.207.254164.9.207.2554,094
158164.9.208.0/20164.9.208.1 to 164.9.223.254164.9.223.2554,094
159164.9.224.0/20164.9.224.1 to 164.9.239.254164.9.239.2554,094
160164.9.240.0/20164.9.240.1 to 164.9.255.254164.9.255.2554,094
161164.10.0.0/20164.10.0.1 to 164.10.15.254164.10.15.2554,094
162164.10.16.0/20164.10.16.1 to 164.10.31.254164.10.31.2554,094
163164.10.32.0/20164.10.32.1 to 164.10.47.254164.10.47.2554,094
164164.10.48.0/20164.10.48.1 to 164.10.63.254164.10.63.2554,094
165164.10.64.0/20164.10.64.1 to 164.10.79.254164.10.79.2554,094
166164.10.80.0/20164.10.80.1 to 164.10.95.254164.10.95.2554,094
167164.10.96.0/20164.10.96.1 to 164.10.111.254164.10.111.2554,094
168164.10.112.0/20164.10.112.1 to 164.10.127.254164.10.127.2554,094
169164.10.128.0/20164.10.128.1 to 164.10.143.254164.10.143.2554,094
170164.10.144.0/20164.10.144.1 to 164.10.159.254164.10.159.2554,094
171164.10.160.0/20164.10.160.1 to 164.10.175.254164.10.175.2554,094
172164.10.176.0/20164.10.176.1 to 164.10.191.254164.10.191.2554,094
173164.10.192.0/20164.10.192.1 to 164.10.207.254164.10.207.2554,094
174164.10.208.0/20164.10.208.1 to 164.10.223.254164.10.223.2554,094
175164.10.224.0/20164.10.224.1 to 164.10.239.254164.10.239.2554,094
176164.10.240.0/20164.10.240.1 to 164.10.255.254164.10.255.2554,094
177164.11.0.0/20164.11.0.1 to 164.11.15.254164.11.15.2554,094
178164.11.16.0/20164.11.16.1 to 164.11.31.254164.11.31.2554,094
179164.11.32.0/20164.11.32.1 to 164.11.47.254164.11.47.2554,094
180164.11.48.0/20164.11.48.1 to 164.11.63.254164.11.63.2554,094
181164.11.64.0/20164.11.64.1 to 164.11.79.254164.11.79.2554,094
182164.11.80.0/20164.11.80.1 to 164.11.95.254164.11.95.2554,094
183164.11.96.0/20164.11.96.1 to 164.11.111.254164.11.111.2554,094
184164.11.112.0/20164.11.112.1 to 164.11.127.254164.11.127.2554,094
185164.11.128.0/20164.11.128.1 to 164.11.143.254164.11.143.2554,094
186164.11.144.0/20164.11.144.1 to 164.11.159.254164.11.159.2554,094
187164.11.160.0/20164.11.160.1 to 164.11.175.254164.11.175.2554,094
188164.11.176.0/20164.11.176.1 to 164.11.191.254164.11.191.2554,094
189164.11.192.0/20164.11.192.1 to 164.11.207.254164.11.207.2554,094
190164.11.208.0/20164.11.208.1 to 164.11.223.254164.11.223.2554,094
191164.11.224.0/20164.11.224.1 to 164.11.239.254164.11.239.2554,094
192164.11.240.0/20164.11.240.1 to 164.11.255.254164.11.255.2554,094
193164.12.0.0/20164.12.0.1 to 164.12.15.254164.12.15.2554,094
194164.12.16.0/20164.12.16.1 to 164.12.31.254164.12.31.2554,094
195164.12.32.0/20164.12.32.1 to 164.12.47.254164.12.47.2554,094
196164.12.48.0/20164.12.48.1 to 164.12.63.254164.12.63.2554,094
197164.12.64.0/20164.12.64.1 to 164.12.79.254164.12.79.2554,094
198164.12.80.0/20164.12.80.1 to 164.12.95.254164.12.95.2554,094
199164.12.96.0/20164.12.96.1 to 164.12.111.254164.12.111.2554,094
200164.12.112.0/20164.12.112.1 to 164.12.127.254164.12.127.2554,094
201164.12.128.0/20164.12.128.1 to 164.12.143.254164.12.143.2554,094
202164.12.144.0/20164.12.144.1 to 164.12.159.254164.12.159.2554,094
203164.12.160.0/20164.12.160.1 to 164.12.175.254164.12.175.2554,094
204164.12.176.0/20164.12.176.1 to 164.12.191.254164.12.191.2554,094
205164.12.192.0/20164.12.192.1 to 164.12.207.254164.12.207.2554,094
206164.12.208.0/20164.12.208.1 to 164.12.223.254164.12.223.2554,094
207164.12.224.0/20164.12.224.1 to 164.12.239.254164.12.239.2554,094
208164.12.240.0/20164.12.240.1 to 164.12.255.254164.12.255.2554,094
209164.13.0.0/20164.13.0.1 to 164.13.15.254164.13.15.2554,094
210164.13.16.0/20164.13.16.1 to 164.13.31.254164.13.31.2554,094
211164.13.32.0/20164.13.32.1 to 164.13.47.254164.13.47.2554,094
212164.13.48.0/20164.13.48.1 to 164.13.63.254164.13.63.2554,094
213164.13.64.0/20164.13.64.1 to 164.13.79.254164.13.79.2554,094
214164.13.80.0/20164.13.80.1 to 164.13.95.254164.13.95.2554,094
215164.13.96.0/20164.13.96.1 to 164.13.111.254164.13.111.2554,094
216164.13.112.0/20164.13.112.1 to 164.13.127.254164.13.127.2554,094
217164.13.128.0/20164.13.128.1 to 164.13.143.254164.13.143.2554,094
218164.13.144.0/20164.13.144.1 to 164.13.159.254164.13.159.2554,094
219164.13.160.0/20164.13.160.1 to 164.13.175.254164.13.175.2554,094
220164.13.176.0/20164.13.176.1 to 164.13.191.254164.13.191.2554,094
221164.13.192.0/20164.13.192.1 to 164.13.207.254164.13.207.2554,094
222164.13.208.0/20164.13.208.1 to 164.13.223.254164.13.223.2554,094
223164.13.224.0/20164.13.224.1 to 164.13.239.254164.13.239.2554,094
224164.13.240.0/20164.13.240.1 to 164.13.255.254164.13.255.2554,094
225164.14.0.0/20164.14.0.1 to 164.14.15.254164.14.15.2554,094
226164.14.16.0/20164.14.16.1 to 164.14.31.254164.14.31.2554,094
227164.14.32.0/20164.14.32.1 to 164.14.47.254164.14.47.2554,094
228164.14.48.0/20164.14.48.1 to 164.14.63.254164.14.63.2554,094
229164.14.64.0/20164.14.64.1 to 164.14.79.254164.14.79.2554,094
230164.14.80.0/20164.14.80.1 to 164.14.95.254164.14.95.2554,094
231164.14.96.0/20164.14.96.1 to 164.14.111.254164.14.111.2554,094
232164.14.112.0/20164.14.112.1 to 164.14.127.254164.14.127.2554,094
233164.14.128.0/20164.14.128.1 to 164.14.143.254164.14.143.2554,094
234164.14.144.0/20164.14.144.1 to 164.14.159.254164.14.159.2554,094
235164.14.160.0/20164.14.160.1 to 164.14.175.254164.14.175.2554,094
236164.14.176.0/20164.14.176.1 to 164.14.191.254164.14.191.2554,094
237164.14.192.0/20164.14.192.1 to 164.14.207.254164.14.207.2554,094
238164.14.208.0/20164.14.208.1 to 164.14.223.254164.14.223.2554,094
239164.14.224.0/20164.14.224.1 to 164.14.239.254164.14.239.2554,094
240164.14.240.0/20164.14.240.1 to 164.14.255.254164.14.255.2554,094
241164.15.0.0/20164.15.0.1 to 164.15.15.254164.15.15.2554,094
242164.15.16.0/20164.15.16.1 to 164.15.31.254164.15.31.2554,094
243164.15.32.0/20164.15.32.1 to 164.15.47.254164.15.47.2554,094
244164.15.48.0/20164.15.48.1 to 164.15.63.254164.15.63.2554,094
245164.15.64.0/20164.15.64.1 to 164.15.79.254164.15.79.2554,094
246164.15.80.0/20164.15.80.1 to 164.15.95.254164.15.95.2554,094
247164.15.96.0/20164.15.96.1 to 164.15.111.254164.15.111.2554,094
248164.15.112.0/20164.15.112.1 to 164.15.127.254164.15.127.2554,094
249164.15.128.0/20164.15.128.1 to 164.15.143.254164.15.143.2554,094
250164.15.144.0/20164.15.144.1 to 164.15.159.254164.15.159.2554,094
251164.15.160.0/20164.15.160.1 to 164.15.175.254164.15.175.2554,094
252164.15.176.0/20164.15.176.1 to 164.15.191.254164.15.191.2554,094
253164.15.192.0/20164.15.192.1 to 164.15.207.254164.15.207.2554,094
254164.15.208.0/20164.15.208.1 to 164.15.223.254164.15.223.2554,094
255164.15.224.0/20164.15.224.1 to 164.15.239.254164.15.239.2554,094
256164.15.240.0/20164.15.240.1 to 164.15.255.254164.15.255.2554,094

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.