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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.

Network126.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
126.0.0.0
Broadcast address
126.255.255.255
First usable
126.0.0.1
Last usable
126.255.255.254
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
A (default /8)
As numbers
Hex 7E000000 · Integer 2113929216 to 2130706431
Reverse DNS zone
126.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01111110..00000000.00000000.00000000126.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network01111110..00000000.00000000.00000000126.0.0.0
Broadcast01111110..11111111.11111111.11111111126.255.255.255
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)

126.0.0.0/8 makes 4,096 subnets of /20; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1126.0.0.0/20126.0.0.1 to 126.0.15.254126.0.15.2554,094
2126.0.16.0/20126.0.16.1 to 126.0.31.254126.0.31.2554,094
3126.0.32.0/20126.0.32.1 to 126.0.47.254126.0.47.2554,094
4126.0.48.0/20126.0.48.1 to 126.0.63.254126.0.63.2554,094
5126.0.64.0/20126.0.64.1 to 126.0.79.254126.0.79.2554,094
6126.0.80.0/20126.0.80.1 to 126.0.95.254126.0.95.2554,094
7126.0.96.0/20126.0.96.1 to 126.0.111.254126.0.111.2554,094
8126.0.112.0/20126.0.112.1 to 126.0.127.254126.0.127.2554,094
9126.0.128.0/20126.0.128.1 to 126.0.143.254126.0.143.2554,094
10126.0.144.0/20126.0.144.1 to 126.0.159.254126.0.159.2554,094
11126.0.160.0/20126.0.160.1 to 126.0.175.254126.0.175.2554,094
12126.0.176.0/20126.0.176.1 to 126.0.191.254126.0.191.2554,094
13126.0.192.0/20126.0.192.1 to 126.0.207.254126.0.207.2554,094
14126.0.208.0/20126.0.208.1 to 126.0.223.254126.0.223.2554,094
15126.0.224.0/20126.0.224.1 to 126.0.239.254126.0.239.2554,094
16126.0.240.0/20126.0.240.1 to 126.0.255.254126.0.255.2554,094
17126.1.0.0/20126.1.0.1 to 126.1.15.254126.1.15.2554,094
18126.1.16.0/20126.1.16.1 to 126.1.31.254126.1.31.2554,094
19126.1.32.0/20126.1.32.1 to 126.1.47.254126.1.47.2554,094
20126.1.48.0/20126.1.48.1 to 126.1.63.254126.1.63.2554,094
21126.1.64.0/20126.1.64.1 to 126.1.79.254126.1.79.2554,094
22126.1.80.0/20126.1.80.1 to 126.1.95.254126.1.95.2554,094
23126.1.96.0/20126.1.96.1 to 126.1.111.254126.1.111.2554,094
24126.1.112.0/20126.1.112.1 to 126.1.127.254126.1.127.2554,094
25126.1.128.0/20126.1.128.1 to 126.1.143.254126.1.143.2554,094
26126.1.144.0/20126.1.144.1 to 126.1.159.254126.1.159.2554,094
27126.1.160.0/20126.1.160.1 to 126.1.175.254126.1.175.2554,094
28126.1.176.0/20126.1.176.1 to 126.1.191.254126.1.191.2554,094
29126.1.192.0/20126.1.192.1 to 126.1.207.254126.1.207.2554,094
30126.1.208.0/20126.1.208.1 to 126.1.223.254126.1.223.2554,094
31126.1.224.0/20126.1.224.1 to 126.1.239.254126.1.239.2554,094
32126.1.240.0/20126.1.240.1 to 126.1.255.254126.1.255.2554,094
33126.2.0.0/20126.2.0.1 to 126.2.15.254126.2.15.2554,094
34126.2.16.0/20126.2.16.1 to 126.2.31.254126.2.31.2554,094
35126.2.32.0/20126.2.32.1 to 126.2.47.254126.2.47.2554,094
36126.2.48.0/20126.2.48.1 to 126.2.63.254126.2.63.2554,094
37126.2.64.0/20126.2.64.1 to 126.2.79.254126.2.79.2554,094
38126.2.80.0/20126.2.80.1 to 126.2.95.254126.2.95.2554,094
39126.2.96.0/20126.2.96.1 to 126.2.111.254126.2.111.2554,094
40126.2.112.0/20126.2.112.1 to 126.2.127.254126.2.127.2554,094
41126.2.128.0/20126.2.128.1 to 126.2.143.254126.2.143.2554,094
42126.2.144.0/20126.2.144.1 to 126.2.159.254126.2.159.2554,094
43126.2.160.0/20126.2.160.1 to 126.2.175.254126.2.175.2554,094
44126.2.176.0/20126.2.176.1 to 126.2.191.254126.2.191.2554,094
45126.2.192.0/20126.2.192.1 to 126.2.207.254126.2.207.2554,094
46126.2.208.0/20126.2.208.1 to 126.2.223.254126.2.223.2554,094
47126.2.224.0/20126.2.224.1 to 126.2.239.254126.2.239.2554,094
48126.2.240.0/20126.2.240.1 to 126.2.255.254126.2.255.2554,094
49126.3.0.0/20126.3.0.1 to 126.3.15.254126.3.15.2554,094
50126.3.16.0/20126.3.16.1 to 126.3.31.254126.3.31.2554,094
51126.3.32.0/20126.3.32.1 to 126.3.47.254126.3.47.2554,094
52126.3.48.0/20126.3.48.1 to 126.3.63.254126.3.63.2554,094
53126.3.64.0/20126.3.64.1 to 126.3.79.254126.3.79.2554,094
54126.3.80.0/20126.3.80.1 to 126.3.95.254126.3.95.2554,094
55126.3.96.0/20126.3.96.1 to 126.3.111.254126.3.111.2554,094
56126.3.112.0/20126.3.112.1 to 126.3.127.254126.3.127.2554,094
57126.3.128.0/20126.3.128.1 to 126.3.143.254126.3.143.2554,094
58126.3.144.0/20126.3.144.1 to 126.3.159.254126.3.159.2554,094
59126.3.160.0/20126.3.160.1 to 126.3.175.254126.3.175.2554,094
60126.3.176.0/20126.3.176.1 to 126.3.191.254126.3.191.2554,094
61126.3.192.0/20126.3.192.1 to 126.3.207.254126.3.207.2554,094
62126.3.208.0/20126.3.208.1 to 126.3.223.254126.3.223.2554,094
63126.3.224.0/20126.3.224.1 to 126.3.239.254126.3.239.2554,094
64126.3.240.0/20126.3.240.1 to 126.3.255.254126.3.255.2554,094
65126.4.0.0/20126.4.0.1 to 126.4.15.254126.4.15.2554,094
66126.4.16.0/20126.4.16.1 to 126.4.31.254126.4.31.2554,094
67126.4.32.0/20126.4.32.1 to 126.4.47.254126.4.47.2554,094
68126.4.48.0/20126.4.48.1 to 126.4.63.254126.4.63.2554,094
69126.4.64.0/20126.4.64.1 to 126.4.79.254126.4.79.2554,094
70126.4.80.0/20126.4.80.1 to 126.4.95.254126.4.95.2554,094
71126.4.96.0/20126.4.96.1 to 126.4.111.254126.4.111.2554,094
72126.4.112.0/20126.4.112.1 to 126.4.127.254126.4.127.2554,094
73126.4.128.0/20126.4.128.1 to 126.4.143.254126.4.143.2554,094
74126.4.144.0/20126.4.144.1 to 126.4.159.254126.4.159.2554,094
75126.4.160.0/20126.4.160.1 to 126.4.175.254126.4.175.2554,094
76126.4.176.0/20126.4.176.1 to 126.4.191.254126.4.191.2554,094
77126.4.192.0/20126.4.192.1 to 126.4.207.254126.4.207.2554,094
78126.4.208.0/20126.4.208.1 to 126.4.223.254126.4.223.2554,094
79126.4.224.0/20126.4.224.1 to 126.4.239.254126.4.239.2554,094
80126.4.240.0/20126.4.240.1 to 126.4.255.254126.4.255.2554,094
81126.5.0.0/20126.5.0.1 to 126.5.15.254126.5.15.2554,094
82126.5.16.0/20126.5.16.1 to 126.5.31.254126.5.31.2554,094
83126.5.32.0/20126.5.32.1 to 126.5.47.254126.5.47.2554,094
84126.5.48.0/20126.5.48.1 to 126.5.63.254126.5.63.2554,094
85126.5.64.0/20126.5.64.1 to 126.5.79.254126.5.79.2554,094
86126.5.80.0/20126.5.80.1 to 126.5.95.254126.5.95.2554,094
87126.5.96.0/20126.5.96.1 to 126.5.111.254126.5.111.2554,094
88126.5.112.0/20126.5.112.1 to 126.5.127.254126.5.127.2554,094
89126.5.128.0/20126.5.128.1 to 126.5.143.254126.5.143.2554,094
90126.5.144.0/20126.5.144.1 to 126.5.159.254126.5.159.2554,094
91126.5.160.0/20126.5.160.1 to 126.5.175.254126.5.175.2554,094
92126.5.176.0/20126.5.176.1 to 126.5.191.254126.5.191.2554,094
93126.5.192.0/20126.5.192.1 to 126.5.207.254126.5.207.2554,094
94126.5.208.0/20126.5.208.1 to 126.5.223.254126.5.223.2554,094
95126.5.224.0/20126.5.224.1 to 126.5.239.254126.5.239.2554,094
96126.5.240.0/20126.5.240.1 to 126.5.255.254126.5.255.2554,094
97126.6.0.0/20126.6.0.1 to 126.6.15.254126.6.15.2554,094
98126.6.16.0/20126.6.16.1 to 126.6.31.254126.6.31.2554,094
99126.6.32.0/20126.6.32.1 to 126.6.47.254126.6.47.2554,094
100126.6.48.0/20126.6.48.1 to 126.6.63.254126.6.63.2554,094
101126.6.64.0/20126.6.64.1 to 126.6.79.254126.6.79.2554,094
102126.6.80.0/20126.6.80.1 to 126.6.95.254126.6.95.2554,094
103126.6.96.0/20126.6.96.1 to 126.6.111.254126.6.111.2554,094
104126.6.112.0/20126.6.112.1 to 126.6.127.254126.6.127.2554,094
105126.6.128.0/20126.6.128.1 to 126.6.143.254126.6.143.2554,094
106126.6.144.0/20126.6.144.1 to 126.6.159.254126.6.159.2554,094
107126.6.160.0/20126.6.160.1 to 126.6.175.254126.6.175.2554,094
108126.6.176.0/20126.6.176.1 to 126.6.191.254126.6.191.2554,094
109126.6.192.0/20126.6.192.1 to 126.6.207.254126.6.207.2554,094
110126.6.208.0/20126.6.208.1 to 126.6.223.254126.6.223.2554,094
111126.6.224.0/20126.6.224.1 to 126.6.239.254126.6.239.2554,094
112126.6.240.0/20126.6.240.1 to 126.6.255.254126.6.255.2554,094
113126.7.0.0/20126.7.0.1 to 126.7.15.254126.7.15.2554,094
114126.7.16.0/20126.7.16.1 to 126.7.31.254126.7.31.2554,094
115126.7.32.0/20126.7.32.1 to 126.7.47.254126.7.47.2554,094
116126.7.48.0/20126.7.48.1 to 126.7.63.254126.7.63.2554,094
117126.7.64.0/20126.7.64.1 to 126.7.79.254126.7.79.2554,094
118126.7.80.0/20126.7.80.1 to 126.7.95.254126.7.95.2554,094
119126.7.96.0/20126.7.96.1 to 126.7.111.254126.7.111.2554,094
120126.7.112.0/20126.7.112.1 to 126.7.127.254126.7.127.2554,094
121126.7.128.0/20126.7.128.1 to 126.7.143.254126.7.143.2554,094
122126.7.144.0/20126.7.144.1 to 126.7.159.254126.7.159.2554,094
123126.7.160.0/20126.7.160.1 to 126.7.175.254126.7.175.2554,094
124126.7.176.0/20126.7.176.1 to 126.7.191.254126.7.191.2554,094
125126.7.192.0/20126.7.192.1 to 126.7.207.254126.7.207.2554,094
126126.7.208.0/20126.7.208.1 to 126.7.223.254126.7.223.2554,094
127126.7.224.0/20126.7.224.1 to 126.7.239.254126.7.239.2554,094
128126.7.240.0/20126.7.240.1 to 126.7.255.254126.7.255.2554,094
129126.8.0.0/20126.8.0.1 to 126.8.15.254126.8.15.2554,094
130126.8.16.0/20126.8.16.1 to 126.8.31.254126.8.31.2554,094
131126.8.32.0/20126.8.32.1 to 126.8.47.254126.8.47.2554,094
132126.8.48.0/20126.8.48.1 to 126.8.63.254126.8.63.2554,094
133126.8.64.0/20126.8.64.1 to 126.8.79.254126.8.79.2554,094
134126.8.80.0/20126.8.80.1 to 126.8.95.254126.8.95.2554,094
135126.8.96.0/20126.8.96.1 to 126.8.111.254126.8.111.2554,094
136126.8.112.0/20126.8.112.1 to 126.8.127.254126.8.127.2554,094
137126.8.128.0/20126.8.128.1 to 126.8.143.254126.8.143.2554,094
138126.8.144.0/20126.8.144.1 to 126.8.159.254126.8.159.2554,094
139126.8.160.0/20126.8.160.1 to 126.8.175.254126.8.175.2554,094
140126.8.176.0/20126.8.176.1 to 126.8.191.254126.8.191.2554,094
141126.8.192.0/20126.8.192.1 to 126.8.207.254126.8.207.2554,094
142126.8.208.0/20126.8.208.1 to 126.8.223.254126.8.223.2554,094
143126.8.224.0/20126.8.224.1 to 126.8.239.254126.8.239.2554,094
144126.8.240.0/20126.8.240.1 to 126.8.255.254126.8.255.2554,094
145126.9.0.0/20126.9.0.1 to 126.9.15.254126.9.15.2554,094
146126.9.16.0/20126.9.16.1 to 126.9.31.254126.9.31.2554,094
147126.9.32.0/20126.9.32.1 to 126.9.47.254126.9.47.2554,094
148126.9.48.0/20126.9.48.1 to 126.9.63.254126.9.63.2554,094
149126.9.64.0/20126.9.64.1 to 126.9.79.254126.9.79.2554,094
150126.9.80.0/20126.9.80.1 to 126.9.95.254126.9.95.2554,094
151126.9.96.0/20126.9.96.1 to 126.9.111.254126.9.111.2554,094
152126.9.112.0/20126.9.112.1 to 126.9.127.254126.9.127.2554,094
153126.9.128.0/20126.9.128.1 to 126.9.143.254126.9.143.2554,094
154126.9.144.0/20126.9.144.1 to 126.9.159.254126.9.159.2554,094
155126.9.160.0/20126.9.160.1 to 126.9.175.254126.9.175.2554,094
156126.9.176.0/20126.9.176.1 to 126.9.191.254126.9.191.2554,094
157126.9.192.0/20126.9.192.1 to 126.9.207.254126.9.207.2554,094
158126.9.208.0/20126.9.208.1 to 126.9.223.254126.9.223.2554,094
159126.9.224.0/20126.9.224.1 to 126.9.239.254126.9.239.2554,094
160126.9.240.0/20126.9.240.1 to 126.9.255.254126.9.255.2554,094
161126.10.0.0/20126.10.0.1 to 126.10.15.254126.10.15.2554,094
162126.10.16.0/20126.10.16.1 to 126.10.31.254126.10.31.2554,094
163126.10.32.0/20126.10.32.1 to 126.10.47.254126.10.47.2554,094
164126.10.48.0/20126.10.48.1 to 126.10.63.254126.10.63.2554,094
165126.10.64.0/20126.10.64.1 to 126.10.79.254126.10.79.2554,094
166126.10.80.0/20126.10.80.1 to 126.10.95.254126.10.95.2554,094
167126.10.96.0/20126.10.96.1 to 126.10.111.254126.10.111.2554,094
168126.10.112.0/20126.10.112.1 to 126.10.127.254126.10.127.2554,094
169126.10.128.0/20126.10.128.1 to 126.10.143.254126.10.143.2554,094
170126.10.144.0/20126.10.144.1 to 126.10.159.254126.10.159.2554,094
171126.10.160.0/20126.10.160.1 to 126.10.175.254126.10.175.2554,094
172126.10.176.0/20126.10.176.1 to 126.10.191.254126.10.191.2554,094
173126.10.192.0/20126.10.192.1 to 126.10.207.254126.10.207.2554,094
174126.10.208.0/20126.10.208.1 to 126.10.223.254126.10.223.2554,094
175126.10.224.0/20126.10.224.1 to 126.10.239.254126.10.239.2554,094
176126.10.240.0/20126.10.240.1 to 126.10.255.254126.10.255.2554,094
177126.11.0.0/20126.11.0.1 to 126.11.15.254126.11.15.2554,094
178126.11.16.0/20126.11.16.1 to 126.11.31.254126.11.31.2554,094
179126.11.32.0/20126.11.32.1 to 126.11.47.254126.11.47.2554,094
180126.11.48.0/20126.11.48.1 to 126.11.63.254126.11.63.2554,094
181126.11.64.0/20126.11.64.1 to 126.11.79.254126.11.79.2554,094
182126.11.80.0/20126.11.80.1 to 126.11.95.254126.11.95.2554,094
183126.11.96.0/20126.11.96.1 to 126.11.111.254126.11.111.2554,094
184126.11.112.0/20126.11.112.1 to 126.11.127.254126.11.127.2554,094
185126.11.128.0/20126.11.128.1 to 126.11.143.254126.11.143.2554,094
186126.11.144.0/20126.11.144.1 to 126.11.159.254126.11.159.2554,094
187126.11.160.0/20126.11.160.1 to 126.11.175.254126.11.175.2554,094
188126.11.176.0/20126.11.176.1 to 126.11.191.254126.11.191.2554,094
189126.11.192.0/20126.11.192.1 to 126.11.207.254126.11.207.2554,094
190126.11.208.0/20126.11.208.1 to 126.11.223.254126.11.223.2554,094
191126.11.224.0/20126.11.224.1 to 126.11.239.254126.11.239.2554,094
192126.11.240.0/20126.11.240.1 to 126.11.255.254126.11.255.2554,094
193126.12.0.0/20126.12.0.1 to 126.12.15.254126.12.15.2554,094
194126.12.16.0/20126.12.16.1 to 126.12.31.254126.12.31.2554,094
195126.12.32.0/20126.12.32.1 to 126.12.47.254126.12.47.2554,094
196126.12.48.0/20126.12.48.1 to 126.12.63.254126.12.63.2554,094
197126.12.64.0/20126.12.64.1 to 126.12.79.254126.12.79.2554,094
198126.12.80.0/20126.12.80.1 to 126.12.95.254126.12.95.2554,094
199126.12.96.0/20126.12.96.1 to 126.12.111.254126.12.111.2554,094
200126.12.112.0/20126.12.112.1 to 126.12.127.254126.12.127.2554,094
201126.12.128.0/20126.12.128.1 to 126.12.143.254126.12.143.2554,094
202126.12.144.0/20126.12.144.1 to 126.12.159.254126.12.159.2554,094
203126.12.160.0/20126.12.160.1 to 126.12.175.254126.12.175.2554,094
204126.12.176.0/20126.12.176.1 to 126.12.191.254126.12.191.2554,094
205126.12.192.0/20126.12.192.1 to 126.12.207.254126.12.207.2554,094
206126.12.208.0/20126.12.208.1 to 126.12.223.254126.12.223.2554,094
207126.12.224.0/20126.12.224.1 to 126.12.239.254126.12.239.2554,094
208126.12.240.0/20126.12.240.1 to 126.12.255.254126.12.255.2554,094
209126.13.0.0/20126.13.0.1 to 126.13.15.254126.13.15.2554,094
210126.13.16.0/20126.13.16.1 to 126.13.31.254126.13.31.2554,094
211126.13.32.0/20126.13.32.1 to 126.13.47.254126.13.47.2554,094
212126.13.48.0/20126.13.48.1 to 126.13.63.254126.13.63.2554,094
213126.13.64.0/20126.13.64.1 to 126.13.79.254126.13.79.2554,094
214126.13.80.0/20126.13.80.1 to 126.13.95.254126.13.95.2554,094
215126.13.96.0/20126.13.96.1 to 126.13.111.254126.13.111.2554,094
216126.13.112.0/20126.13.112.1 to 126.13.127.254126.13.127.2554,094
217126.13.128.0/20126.13.128.1 to 126.13.143.254126.13.143.2554,094
218126.13.144.0/20126.13.144.1 to 126.13.159.254126.13.159.2554,094
219126.13.160.0/20126.13.160.1 to 126.13.175.254126.13.175.2554,094
220126.13.176.0/20126.13.176.1 to 126.13.191.254126.13.191.2554,094
221126.13.192.0/20126.13.192.1 to 126.13.207.254126.13.207.2554,094
222126.13.208.0/20126.13.208.1 to 126.13.223.254126.13.223.2554,094
223126.13.224.0/20126.13.224.1 to 126.13.239.254126.13.239.2554,094
224126.13.240.0/20126.13.240.1 to 126.13.255.254126.13.255.2554,094
225126.14.0.0/20126.14.0.1 to 126.14.15.254126.14.15.2554,094
226126.14.16.0/20126.14.16.1 to 126.14.31.254126.14.31.2554,094
227126.14.32.0/20126.14.32.1 to 126.14.47.254126.14.47.2554,094
228126.14.48.0/20126.14.48.1 to 126.14.63.254126.14.63.2554,094
229126.14.64.0/20126.14.64.1 to 126.14.79.254126.14.79.2554,094
230126.14.80.0/20126.14.80.1 to 126.14.95.254126.14.95.2554,094
231126.14.96.0/20126.14.96.1 to 126.14.111.254126.14.111.2554,094
232126.14.112.0/20126.14.112.1 to 126.14.127.254126.14.127.2554,094
233126.14.128.0/20126.14.128.1 to 126.14.143.254126.14.143.2554,094
234126.14.144.0/20126.14.144.1 to 126.14.159.254126.14.159.2554,094
235126.14.160.0/20126.14.160.1 to 126.14.175.254126.14.175.2554,094
236126.14.176.0/20126.14.176.1 to 126.14.191.254126.14.191.2554,094
237126.14.192.0/20126.14.192.1 to 126.14.207.254126.14.207.2554,094
238126.14.208.0/20126.14.208.1 to 126.14.223.254126.14.223.2554,094
239126.14.224.0/20126.14.224.1 to 126.14.239.254126.14.239.2554,094
240126.14.240.0/20126.14.240.1 to 126.14.255.254126.14.255.2554,094
241126.15.0.0/20126.15.0.1 to 126.15.15.254126.15.15.2554,094
242126.15.16.0/20126.15.16.1 to 126.15.31.254126.15.31.2554,094
243126.15.32.0/20126.15.32.1 to 126.15.47.254126.15.47.2554,094
244126.15.48.0/20126.15.48.1 to 126.15.63.254126.15.63.2554,094
245126.15.64.0/20126.15.64.1 to 126.15.79.254126.15.79.2554,094
246126.15.80.0/20126.15.80.1 to 126.15.95.254126.15.95.2554,094
247126.15.96.0/20126.15.96.1 to 126.15.111.254126.15.111.2554,094
248126.15.112.0/20126.15.112.1 to 126.15.127.254126.15.127.2554,094
249126.15.128.0/20126.15.128.1 to 126.15.143.254126.15.143.2554,094
250126.15.144.0/20126.15.144.1 to 126.15.159.254126.15.159.2554,094
251126.15.160.0/20126.15.160.1 to 126.15.175.254126.15.175.2554,094
252126.15.176.0/20126.15.176.1 to 126.15.191.254126.15.191.2554,094
253126.15.192.0/20126.15.192.1 to 126.15.207.254126.15.207.2554,094
254126.15.208.0/20126.15.208.1 to 126.15.223.254126.15.223.2554,094
255126.15.224.0/20126.15.224.1 to 126.15.239.254126.15.239.2554,094
256126.15.240.0/20126.15.240.1 to 126.15.255.254126.15.255.2554,094

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.