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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.

Network139.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
139.0.0.0
Broadcast address
139.255.255.255
First usable
139.0.0.1
Last usable
139.255.255.254
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 8B000000 · Integer 2332033024 to 2348810239
Reverse DNS zone
139.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10001011..00000000.00000000.00000000139.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network10001011..00000000.00000000.00000000139.0.0.0
Broadcast10001011..11111111.11111111.11111111139.255.255.255
Split into smaller subnets/20
/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)

139.0.0.0/8 makes 4,096 subnets of /20; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1139.0.0.0/20139.0.0.1 to 139.0.15.254139.0.15.2554,094
2139.0.16.0/20139.0.16.1 to 139.0.31.254139.0.31.2554,094
3139.0.32.0/20139.0.32.1 to 139.0.47.254139.0.47.2554,094
4139.0.48.0/20139.0.48.1 to 139.0.63.254139.0.63.2554,094
5139.0.64.0/20139.0.64.1 to 139.0.79.254139.0.79.2554,094
6139.0.80.0/20139.0.80.1 to 139.0.95.254139.0.95.2554,094
7139.0.96.0/20139.0.96.1 to 139.0.111.254139.0.111.2554,094
8139.0.112.0/20139.0.112.1 to 139.0.127.254139.0.127.2554,094
9139.0.128.0/20139.0.128.1 to 139.0.143.254139.0.143.2554,094
10139.0.144.0/20139.0.144.1 to 139.0.159.254139.0.159.2554,094
11139.0.160.0/20139.0.160.1 to 139.0.175.254139.0.175.2554,094
12139.0.176.0/20139.0.176.1 to 139.0.191.254139.0.191.2554,094
13139.0.192.0/20139.0.192.1 to 139.0.207.254139.0.207.2554,094
14139.0.208.0/20139.0.208.1 to 139.0.223.254139.0.223.2554,094
15139.0.224.0/20139.0.224.1 to 139.0.239.254139.0.239.2554,094
16139.0.240.0/20139.0.240.1 to 139.0.255.254139.0.255.2554,094
17139.1.0.0/20139.1.0.1 to 139.1.15.254139.1.15.2554,094
18139.1.16.0/20139.1.16.1 to 139.1.31.254139.1.31.2554,094
19139.1.32.0/20139.1.32.1 to 139.1.47.254139.1.47.2554,094
20139.1.48.0/20139.1.48.1 to 139.1.63.254139.1.63.2554,094
21139.1.64.0/20139.1.64.1 to 139.1.79.254139.1.79.2554,094
22139.1.80.0/20139.1.80.1 to 139.1.95.254139.1.95.2554,094
23139.1.96.0/20139.1.96.1 to 139.1.111.254139.1.111.2554,094
24139.1.112.0/20139.1.112.1 to 139.1.127.254139.1.127.2554,094
25139.1.128.0/20139.1.128.1 to 139.1.143.254139.1.143.2554,094
26139.1.144.0/20139.1.144.1 to 139.1.159.254139.1.159.2554,094
27139.1.160.0/20139.1.160.1 to 139.1.175.254139.1.175.2554,094
28139.1.176.0/20139.1.176.1 to 139.1.191.254139.1.191.2554,094
29139.1.192.0/20139.1.192.1 to 139.1.207.254139.1.207.2554,094
30139.1.208.0/20139.1.208.1 to 139.1.223.254139.1.223.2554,094
31139.1.224.0/20139.1.224.1 to 139.1.239.254139.1.239.2554,094
32139.1.240.0/20139.1.240.1 to 139.1.255.254139.1.255.2554,094
33139.2.0.0/20139.2.0.1 to 139.2.15.254139.2.15.2554,094
34139.2.16.0/20139.2.16.1 to 139.2.31.254139.2.31.2554,094
35139.2.32.0/20139.2.32.1 to 139.2.47.254139.2.47.2554,094
36139.2.48.0/20139.2.48.1 to 139.2.63.254139.2.63.2554,094
37139.2.64.0/20139.2.64.1 to 139.2.79.254139.2.79.2554,094
38139.2.80.0/20139.2.80.1 to 139.2.95.254139.2.95.2554,094
39139.2.96.0/20139.2.96.1 to 139.2.111.254139.2.111.2554,094
40139.2.112.0/20139.2.112.1 to 139.2.127.254139.2.127.2554,094
41139.2.128.0/20139.2.128.1 to 139.2.143.254139.2.143.2554,094
42139.2.144.0/20139.2.144.1 to 139.2.159.254139.2.159.2554,094
43139.2.160.0/20139.2.160.1 to 139.2.175.254139.2.175.2554,094
44139.2.176.0/20139.2.176.1 to 139.2.191.254139.2.191.2554,094
45139.2.192.0/20139.2.192.1 to 139.2.207.254139.2.207.2554,094
46139.2.208.0/20139.2.208.1 to 139.2.223.254139.2.223.2554,094
47139.2.224.0/20139.2.224.1 to 139.2.239.254139.2.239.2554,094
48139.2.240.0/20139.2.240.1 to 139.2.255.254139.2.255.2554,094
49139.3.0.0/20139.3.0.1 to 139.3.15.254139.3.15.2554,094
50139.3.16.0/20139.3.16.1 to 139.3.31.254139.3.31.2554,094
51139.3.32.0/20139.3.32.1 to 139.3.47.254139.3.47.2554,094
52139.3.48.0/20139.3.48.1 to 139.3.63.254139.3.63.2554,094
53139.3.64.0/20139.3.64.1 to 139.3.79.254139.3.79.2554,094
54139.3.80.0/20139.3.80.1 to 139.3.95.254139.3.95.2554,094
55139.3.96.0/20139.3.96.1 to 139.3.111.254139.3.111.2554,094
56139.3.112.0/20139.3.112.1 to 139.3.127.254139.3.127.2554,094
57139.3.128.0/20139.3.128.1 to 139.3.143.254139.3.143.2554,094
58139.3.144.0/20139.3.144.1 to 139.3.159.254139.3.159.2554,094
59139.3.160.0/20139.3.160.1 to 139.3.175.254139.3.175.2554,094
60139.3.176.0/20139.3.176.1 to 139.3.191.254139.3.191.2554,094
61139.3.192.0/20139.3.192.1 to 139.3.207.254139.3.207.2554,094
62139.3.208.0/20139.3.208.1 to 139.3.223.254139.3.223.2554,094
63139.3.224.0/20139.3.224.1 to 139.3.239.254139.3.239.2554,094
64139.3.240.0/20139.3.240.1 to 139.3.255.254139.3.255.2554,094
65139.4.0.0/20139.4.0.1 to 139.4.15.254139.4.15.2554,094
66139.4.16.0/20139.4.16.1 to 139.4.31.254139.4.31.2554,094
67139.4.32.0/20139.4.32.1 to 139.4.47.254139.4.47.2554,094
68139.4.48.0/20139.4.48.1 to 139.4.63.254139.4.63.2554,094
69139.4.64.0/20139.4.64.1 to 139.4.79.254139.4.79.2554,094
70139.4.80.0/20139.4.80.1 to 139.4.95.254139.4.95.2554,094
71139.4.96.0/20139.4.96.1 to 139.4.111.254139.4.111.2554,094
72139.4.112.0/20139.4.112.1 to 139.4.127.254139.4.127.2554,094
73139.4.128.0/20139.4.128.1 to 139.4.143.254139.4.143.2554,094
74139.4.144.0/20139.4.144.1 to 139.4.159.254139.4.159.2554,094
75139.4.160.0/20139.4.160.1 to 139.4.175.254139.4.175.2554,094
76139.4.176.0/20139.4.176.1 to 139.4.191.254139.4.191.2554,094
77139.4.192.0/20139.4.192.1 to 139.4.207.254139.4.207.2554,094
78139.4.208.0/20139.4.208.1 to 139.4.223.254139.4.223.2554,094
79139.4.224.0/20139.4.224.1 to 139.4.239.254139.4.239.2554,094
80139.4.240.0/20139.4.240.1 to 139.4.255.254139.4.255.2554,094
81139.5.0.0/20139.5.0.1 to 139.5.15.254139.5.15.2554,094
82139.5.16.0/20139.5.16.1 to 139.5.31.254139.5.31.2554,094
83139.5.32.0/20139.5.32.1 to 139.5.47.254139.5.47.2554,094
84139.5.48.0/20139.5.48.1 to 139.5.63.254139.5.63.2554,094
85139.5.64.0/20139.5.64.1 to 139.5.79.254139.5.79.2554,094
86139.5.80.0/20139.5.80.1 to 139.5.95.254139.5.95.2554,094
87139.5.96.0/20139.5.96.1 to 139.5.111.254139.5.111.2554,094
88139.5.112.0/20139.5.112.1 to 139.5.127.254139.5.127.2554,094
89139.5.128.0/20139.5.128.1 to 139.5.143.254139.5.143.2554,094
90139.5.144.0/20139.5.144.1 to 139.5.159.254139.5.159.2554,094
91139.5.160.0/20139.5.160.1 to 139.5.175.254139.5.175.2554,094
92139.5.176.0/20139.5.176.1 to 139.5.191.254139.5.191.2554,094
93139.5.192.0/20139.5.192.1 to 139.5.207.254139.5.207.2554,094
94139.5.208.0/20139.5.208.1 to 139.5.223.254139.5.223.2554,094
95139.5.224.0/20139.5.224.1 to 139.5.239.254139.5.239.2554,094
96139.5.240.0/20139.5.240.1 to 139.5.255.254139.5.255.2554,094
97139.6.0.0/20139.6.0.1 to 139.6.15.254139.6.15.2554,094
98139.6.16.0/20139.6.16.1 to 139.6.31.254139.6.31.2554,094
99139.6.32.0/20139.6.32.1 to 139.6.47.254139.6.47.2554,094
100139.6.48.0/20139.6.48.1 to 139.6.63.254139.6.63.2554,094
101139.6.64.0/20139.6.64.1 to 139.6.79.254139.6.79.2554,094
102139.6.80.0/20139.6.80.1 to 139.6.95.254139.6.95.2554,094
103139.6.96.0/20139.6.96.1 to 139.6.111.254139.6.111.2554,094
104139.6.112.0/20139.6.112.1 to 139.6.127.254139.6.127.2554,094
105139.6.128.0/20139.6.128.1 to 139.6.143.254139.6.143.2554,094
106139.6.144.0/20139.6.144.1 to 139.6.159.254139.6.159.2554,094
107139.6.160.0/20139.6.160.1 to 139.6.175.254139.6.175.2554,094
108139.6.176.0/20139.6.176.1 to 139.6.191.254139.6.191.2554,094
109139.6.192.0/20139.6.192.1 to 139.6.207.254139.6.207.2554,094
110139.6.208.0/20139.6.208.1 to 139.6.223.254139.6.223.2554,094
111139.6.224.0/20139.6.224.1 to 139.6.239.254139.6.239.2554,094
112139.6.240.0/20139.6.240.1 to 139.6.255.254139.6.255.2554,094
113139.7.0.0/20139.7.0.1 to 139.7.15.254139.7.15.2554,094
114139.7.16.0/20139.7.16.1 to 139.7.31.254139.7.31.2554,094
115139.7.32.0/20139.7.32.1 to 139.7.47.254139.7.47.2554,094
116139.7.48.0/20139.7.48.1 to 139.7.63.254139.7.63.2554,094
117139.7.64.0/20139.7.64.1 to 139.7.79.254139.7.79.2554,094
118139.7.80.0/20139.7.80.1 to 139.7.95.254139.7.95.2554,094
119139.7.96.0/20139.7.96.1 to 139.7.111.254139.7.111.2554,094
120139.7.112.0/20139.7.112.1 to 139.7.127.254139.7.127.2554,094
121139.7.128.0/20139.7.128.1 to 139.7.143.254139.7.143.2554,094
122139.7.144.0/20139.7.144.1 to 139.7.159.254139.7.159.2554,094
123139.7.160.0/20139.7.160.1 to 139.7.175.254139.7.175.2554,094
124139.7.176.0/20139.7.176.1 to 139.7.191.254139.7.191.2554,094
125139.7.192.0/20139.7.192.1 to 139.7.207.254139.7.207.2554,094
126139.7.208.0/20139.7.208.1 to 139.7.223.254139.7.223.2554,094
127139.7.224.0/20139.7.224.1 to 139.7.239.254139.7.239.2554,094
128139.7.240.0/20139.7.240.1 to 139.7.255.254139.7.255.2554,094
129139.8.0.0/20139.8.0.1 to 139.8.15.254139.8.15.2554,094
130139.8.16.0/20139.8.16.1 to 139.8.31.254139.8.31.2554,094
131139.8.32.0/20139.8.32.1 to 139.8.47.254139.8.47.2554,094
132139.8.48.0/20139.8.48.1 to 139.8.63.254139.8.63.2554,094
133139.8.64.0/20139.8.64.1 to 139.8.79.254139.8.79.2554,094
134139.8.80.0/20139.8.80.1 to 139.8.95.254139.8.95.2554,094
135139.8.96.0/20139.8.96.1 to 139.8.111.254139.8.111.2554,094
136139.8.112.0/20139.8.112.1 to 139.8.127.254139.8.127.2554,094
137139.8.128.0/20139.8.128.1 to 139.8.143.254139.8.143.2554,094
138139.8.144.0/20139.8.144.1 to 139.8.159.254139.8.159.2554,094
139139.8.160.0/20139.8.160.1 to 139.8.175.254139.8.175.2554,094
140139.8.176.0/20139.8.176.1 to 139.8.191.254139.8.191.2554,094
141139.8.192.0/20139.8.192.1 to 139.8.207.254139.8.207.2554,094
142139.8.208.0/20139.8.208.1 to 139.8.223.254139.8.223.2554,094
143139.8.224.0/20139.8.224.1 to 139.8.239.254139.8.239.2554,094
144139.8.240.0/20139.8.240.1 to 139.8.255.254139.8.255.2554,094
145139.9.0.0/20139.9.0.1 to 139.9.15.254139.9.15.2554,094
146139.9.16.0/20139.9.16.1 to 139.9.31.254139.9.31.2554,094
147139.9.32.0/20139.9.32.1 to 139.9.47.254139.9.47.2554,094
148139.9.48.0/20139.9.48.1 to 139.9.63.254139.9.63.2554,094
149139.9.64.0/20139.9.64.1 to 139.9.79.254139.9.79.2554,094
150139.9.80.0/20139.9.80.1 to 139.9.95.254139.9.95.2554,094
151139.9.96.0/20139.9.96.1 to 139.9.111.254139.9.111.2554,094
152139.9.112.0/20139.9.112.1 to 139.9.127.254139.9.127.2554,094
153139.9.128.0/20139.9.128.1 to 139.9.143.254139.9.143.2554,094
154139.9.144.0/20139.9.144.1 to 139.9.159.254139.9.159.2554,094
155139.9.160.0/20139.9.160.1 to 139.9.175.254139.9.175.2554,094
156139.9.176.0/20139.9.176.1 to 139.9.191.254139.9.191.2554,094
157139.9.192.0/20139.9.192.1 to 139.9.207.254139.9.207.2554,094
158139.9.208.0/20139.9.208.1 to 139.9.223.254139.9.223.2554,094
159139.9.224.0/20139.9.224.1 to 139.9.239.254139.9.239.2554,094
160139.9.240.0/20139.9.240.1 to 139.9.255.254139.9.255.2554,094
161139.10.0.0/20139.10.0.1 to 139.10.15.254139.10.15.2554,094
162139.10.16.0/20139.10.16.1 to 139.10.31.254139.10.31.2554,094
163139.10.32.0/20139.10.32.1 to 139.10.47.254139.10.47.2554,094
164139.10.48.0/20139.10.48.1 to 139.10.63.254139.10.63.2554,094
165139.10.64.0/20139.10.64.1 to 139.10.79.254139.10.79.2554,094
166139.10.80.0/20139.10.80.1 to 139.10.95.254139.10.95.2554,094
167139.10.96.0/20139.10.96.1 to 139.10.111.254139.10.111.2554,094
168139.10.112.0/20139.10.112.1 to 139.10.127.254139.10.127.2554,094
169139.10.128.0/20139.10.128.1 to 139.10.143.254139.10.143.2554,094
170139.10.144.0/20139.10.144.1 to 139.10.159.254139.10.159.2554,094
171139.10.160.0/20139.10.160.1 to 139.10.175.254139.10.175.2554,094
172139.10.176.0/20139.10.176.1 to 139.10.191.254139.10.191.2554,094
173139.10.192.0/20139.10.192.1 to 139.10.207.254139.10.207.2554,094
174139.10.208.0/20139.10.208.1 to 139.10.223.254139.10.223.2554,094
175139.10.224.0/20139.10.224.1 to 139.10.239.254139.10.239.2554,094
176139.10.240.0/20139.10.240.1 to 139.10.255.254139.10.255.2554,094
177139.11.0.0/20139.11.0.1 to 139.11.15.254139.11.15.2554,094
178139.11.16.0/20139.11.16.1 to 139.11.31.254139.11.31.2554,094
179139.11.32.0/20139.11.32.1 to 139.11.47.254139.11.47.2554,094
180139.11.48.0/20139.11.48.1 to 139.11.63.254139.11.63.2554,094
181139.11.64.0/20139.11.64.1 to 139.11.79.254139.11.79.2554,094
182139.11.80.0/20139.11.80.1 to 139.11.95.254139.11.95.2554,094
183139.11.96.0/20139.11.96.1 to 139.11.111.254139.11.111.2554,094
184139.11.112.0/20139.11.112.1 to 139.11.127.254139.11.127.2554,094
185139.11.128.0/20139.11.128.1 to 139.11.143.254139.11.143.2554,094
186139.11.144.0/20139.11.144.1 to 139.11.159.254139.11.159.2554,094
187139.11.160.0/20139.11.160.1 to 139.11.175.254139.11.175.2554,094
188139.11.176.0/20139.11.176.1 to 139.11.191.254139.11.191.2554,094
189139.11.192.0/20139.11.192.1 to 139.11.207.254139.11.207.2554,094
190139.11.208.0/20139.11.208.1 to 139.11.223.254139.11.223.2554,094
191139.11.224.0/20139.11.224.1 to 139.11.239.254139.11.239.2554,094
192139.11.240.0/20139.11.240.1 to 139.11.255.254139.11.255.2554,094
193139.12.0.0/20139.12.0.1 to 139.12.15.254139.12.15.2554,094
194139.12.16.0/20139.12.16.1 to 139.12.31.254139.12.31.2554,094
195139.12.32.0/20139.12.32.1 to 139.12.47.254139.12.47.2554,094
196139.12.48.0/20139.12.48.1 to 139.12.63.254139.12.63.2554,094
197139.12.64.0/20139.12.64.1 to 139.12.79.254139.12.79.2554,094
198139.12.80.0/20139.12.80.1 to 139.12.95.254139.12.95.2554,094
199139.12.96.0/20139.12.96.1 to 139.12.111.254139.12.111.2554,094
200139.12.112.0/20139.12.112.1 to 139.12.127.254139.12.127.2554,094
201139.12.128.0/20139.12.128.1 to 139.12.143.254139.12.143.2554,094
202139.12.144.0/20139.12.144.1 to 139.12.159.254139.12.159.2554,094
203139.12.160.0/20139.12.160.1 to 139.12.175.254139.12.175.2554,094
204139.12.176.0/20139.12.176.1 to 139.12.191.254139.12.191.2554,094
205139.12.192.0/20139.12.192.1 to 139.12.207.254139.12.207.2554,094
206139.12.208.0/20139.12.208.1 to 139.12.223.254139.12.223.2554,094
207139.12.224.0/20139.12.224.1 to 139.12.239.254139.12.239.2554,094
208139.12.240.0/20139.12.240.1 to 139.12.255.254139.12.255.2554,094
209139.13.0.0/20139.13.0.1 to 139.13.15.254139.13.15.2554,094
210139.13.16.0/20139.13.16.1 to 139.13.31.254139.13.31.2554,094
211139.13.32.0/20139.13.32.1 to 139.13.47.254139.13.47.2554,094
212139.13.48.0/20139.13.48.1 to 139.13.63.254139.13.63.2554,094
213139.13.64.0/20139.13.64.1 to 139.13.79.254139.13.79.2554,094
214139.13.80.0/20139.13.80.1 to 139.13.95.254139.13.95.2554,094
215139.13.96.0/20139.13.96.1 to 139.13.111.254139.13.111.2554,094
216139.13.112.0/20139.13.112.1 to 139.13.127.254139.13.127.2554,094
217139.13.128.0/20139.13.128.1 to 139.13.143.254139.13.143.2554,094
218139.13.144.0/20139.13.144.1 to 139.13.159.254139.13.159.2554,094
219139.13.160.0/20139.13.160.1 to 139.13.175.254139.13.175.2554,094
220139.13.176.0/20139.13.176.1 to 139.13.191.254139.13.191.2554,094
221139.13.192.0/20139.13.192.1 to 139.13.207.254139.13.207.2554,094
222139.13.208.0/20139.13.208.1 to 139.13.223.254139.13.223.2554,094
223139.13.224.0/20139.13.224.1 to 139.13.239.254139.13.239.2554,094
224139.13.240.0/20139.13.240.1 to 139.13.255.254139.13.255.2554,094
225139.14.0.0/20139.14.0.1 to 139.14.15.254139.14.15.2554,094
226139.14.16.0/20139.14.16.1 to 139.14.31.254139.14.31.2554,094
227139.14.32.0/20139.14.32.1 to 139.14.47.254139.14.47.2554,094
228139.14.48.0/20139.14.48.1 to 139.14.63.254139.14.63.2554,094
229139.14.64.0/20139.14.64.1 to 139.14.79.254139.14.79.2554,094
230139.14.80.0/20139.14.80.1 to 139.14.95.254139.14.95.2554,094
231139.14.96.0/20139.14.96.1 to 139.14.111.254139.14.111.2554,094
232139.14.112.0/20139.14.112.1 to 139.14.127.254139.14.127.2554,094
233139.14.128.0/20139.14.128.1 to 139.14.143.254139.14.143.2554,094
234139.14.144.0/20139.14.144.1 to 139.14.159.254139.14.159.2554,094
235139.14.160.0/20139.14.160.1 to 139.14.175.254139.14.175.2554,094
236139.14.176.0/20139.14.176.1 to 139.14.191.254139.14.191.2554,094
237139.14.192.0/20139.14.192.1 to 139.14.207.254139.14.207.2554,094
238139.14.208.0/20139.14.208.1 to 139.14.223.254139.14.223.2554,094
239139.14.224.0/20139.14.224.1 to 139.14.239.254139.14.239.2554,094
240139.14.240.0/20139.14.240.1 to 139.14.255.254139.14.255.2554,094
241139.15.0.0/20139.15.0.1 to 139.15.15.254139.15.15.2554,094
242139.15.16.0/20139.15.16.1 to 139.15.31.254139.15.31.2554,094
243139.15.32.0/20139.15.32.1 to 139.15.47.254139.15.47.2554,094
244139.15.48.0/20139.15.48.1 to 139.15.63.254139.15.63.2554,094
245139.15.64.0/20139.15.64.1 to 139.15.79.254139.15.79.2554,094
246139.15.80.0/20139.15.80.1 to 139.15.95.254139.15.95.2554,094
247139.15.96.0/20139.15.96.1 to 139.15.111.254139.15.111.2554,094
248139.15.112.0/20139.15.112.1 to 139.15.127.254139.15.127.2554,094
249139.15.128.0/20139.15.128.1 to 139.15.143.254139.15.143.2554,094
250139.15.144.0/20139.15.144.1 to 139.15.159.254139.15.159.2554,094
251139.15.160.0/20139.15.160.1 to 139.15.175.254139.15.175.2554,094
252139.15.176.0/20139.15.176.1 to 139.15.191.254139.15.191.2554,094
253139.15.192.0/20139.15.192.1 to 139.15.207.254139.15.207.2554,094
254139.15.208.0/20139.15.208.1 to 139.15.223.254139.15.223.2554,094
255139.15.224.0/20139.15.224.1 to 139.15.239.254139.15.239.2554,094
256139.15.240.0/20139.15.240.1 to 139.15.255.254139.15.255.2554,094

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.