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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/18
/9 (2)/10 (4)/11 (8)/12 (16)/13 (32)/14 (64)/15 (128)/16 (256)/17 (512)/18 (1,024)/19 (2,048)/20 (4,096)

126.0.0.0/8 makes 1,024 subnets of /18; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1126.0.0.0/18126.0.0.1 to 126.0.63.254126.0.63.25516,382
2126.0.64.0/18126.0.64.1 to 126.0.127.254126.0.127.25516,382
3126.0.128.0/18126.0.128.1 to 126.0.191.254126.0.191.25516,382
4126.0.192.0/18126.0.192.1 to 126.0.255.254126.0.255.25516,382
5126.1.0.0/18126.1.0.1 to 126.1.63.254126.1.63.25516,382
6126.1.64.0/18126.1.64.1 to 126.1.127.254126.1.127.25516,382
7126.1.128.0/18126.1.128.1 to 126.1.191.254126.1.191.25516,382
8126.1.192.0/18126.1.192.1 to 126.1.255.254126.1.255.25516,382
9126.2.0.0/18126.2.0.1 to 126.2.63.254126.2.63.25516,382
10126.2.64.0/18126.2.64.1 to 126.2.127.254126.2.127.25516,382
11126.2.128.0/18126.2.128.1 to 126.2.191.254126.2.191.25516,382
12126.2.192.0/18126.2.192.1 to 126.2.255.254126.2.255.25516,382
13126.3.0.0/18126.3.0.1 to 126.3.63.254126.3.63.25516,382
14126.3.64.0/18126.3.64.1 to 126.3.127.254126.3.127.25516,382
15126.3.128.0/18126.3.128.1 to 126.3.191.254126.3.191.25516,382
16126.3.192.0/18126.3.192.1 to 126.3.255.254126.3.255.25516,382
17126.4.0.0/18126.4.0.1 to 126.4.63.254126.4.63.25516,382
18126.4.64.0/18126.4.64.1 to 126.4.127.254126.4.127.25516,382
19126.4.128.0/18126.4.128.1 to 126.4.191.254126.4.191.25516,382
20126.4.192.0/18126.4.192.1 to 126.4.255.254126.4.255.25516,382
21126.5.0.0/18126.5.0.1 to 126.5.63.254126.5.63.25516,382
22126.5.64.0/18126.5.64.1 to 126.5.127.254126.5.127.25516,382
23126.5.128.0/18126.5.128.1 to 126.5.191.254126.5.191.25516,382
24126.5.192.0/18126.5.192.1 to 126.5.255.254126.5.255.25516,382
25126.6.0.0/18126.6.0.1 to 126.6.63.254126.6.63.25516,382
26126.6.64.0/18126.6.64.1 to 126.6.127.254126.6.127.25516,382
27126.6.128.0/18126.6.128.1 to 126.6.191.254126.6.191.25516,382
28126.6.192.0/18126.6.192.1 to 126.6.255.254126.6.255.25516,382
29126.7.0.0/18126.7.0.1 to 126.7.63.254126.7.63.25516,382
30126.7.64.0/18126.7.64.1 to 126.7.127.254126.7.127.25516,382
31126.7.128.0/18126.7.128.1 to 126.7.191.254126.7.191.25516,382
32126.7.192.0/18126.7.192.1 to 126.7.255.254126.7.255.25516,382
33126.8.0.0/18126.8.0.1 to 126.8.63.254126.8.63.25516,382
34126.8.64.0/18126.8.64.1 to 126.8.127.254126.8.127.25516,382
35126.8.128.0/18126.8.128.1 to 126.8.191.254126.8.191.25516,382
36126.8.192.0/18126.8.192.1 to 126.8.255.254126.8.255.25516,382
37126.9.0.0/18126.9.0.1 to 126.9.63.254126.9.63.25516,382
38126.9.64.0/18126.9.64.1 to 126.9.127.254126.9.127.25516,382
39126.9.128.0/18126.9.128.1 to 126.9.191.254126.9.191.25516,382
40126.9.192.0/18126.9.192.1 to 126.9.255.254126.9.255.25516,382
41126.10.0.0/18126.10.0.1 to 126.10.63.254126.10.63.25516,382
42126.10.64.0/18126.10.64.1 to 126.10.127.254126.10.127.25516,382
43126.10.128.0/18126.10.128.1 to 126.10.191.254126.10.191.25516,382
44126.10.192.0/18126.10.192.1 to 126.10.255.254126.10.255.25516,382
45126.11.0.0/18126.11.0.1 to 126.11.63.254126.11.63.25516,382
46126.11.64.0/18126.11.64.1 to 126.11.127.254126.11.127.25516,382
47126.11.128.0/18126.11.128.1 to 126.11.191.254126.11.191.25516,382
48126.11.192.0/18126.11.192.1 to 126.11.255.254126.11.255.25516,382
49126.12.0.0/18126.12.0.1 to 126.12.63.254126.12.63.25516,382
50126.12.64.0/18126.12.64.1 to 126.12.127.254126.12.127.25516,382
51126.12.128.0/18126.12.128.1 to 126.12.191.254126.12.191.25516,382
52126.12.192.0/18126.12.192.1 to 126.12.255.254126.12.255.25516,382
53126.13.0.0/18126.13.0.1 to 126.13.63.254126.13.63.25516,382
54126.13.64.0/18126.13.64.1 to 126.13.127.254126.13.127.25516,382
55126.13.128.0/18126.13.128.1 to 126.13.191.254126.13.191.25516,382
56126.13.192.0/18126.13.192.1 to 126.13.255.254126.13.255.25516,382
57126.14.0.0/18126.14.0.1 to 126.14.63.254126.14.63.25516,382
58126.14.64.0/18126.14.64.1 to 126.14.127.254126.14.127.25516,382
59126.14.128.0/18126.14.128.1 to 126.14.191.254126.14.191.25516,382
60126.14.192.0/18126.14.192.1 to 126.14.255.254126.14.255.25516,382
61126.15.0.0/18126.15.0.1 to 126.15.63.254126.15.63.25516,382
62126.15.64.0/18126.15.64.1 to 126.15.127.254126.15.127.25516,382
63126.15.128.0/18126.15.128.1 to 126.15.191.254126.15.191.25516,382
64126.15.192.0/18126.15.192.1 to 126.15.255.254126.15.255.25516,382
65126.16.0.0/18126.16.0.1 to 126.16.63.254126.16.63.25516,382
66126.16.64.0/18126.16.64.1 to 126.16.127.254126.16.127.25516,382
67126.16.128.0/18126.16.128.1 to 126.16.191.254126.16.191.25516,382
68126.16.192.0/18126.16.192.1 to 126.16.255.254126.16.255.25516,382
69126.17.0.0/18126.17.0.1 to 126.17.63.254126.17.63.25516,382
70126.17.64.0/18126.17.64.1 to 126.17.127.254126.17.127.25516,382
71126.17.128.0/18126.17.128.1 to 126.17.191.254126.17.191.25516,382
72126.17.192.0/18126.17.192.1 to 126.17.255.254126.17.255.25516,382
73126.18.0.0/18126.18.0.1 to 126.18.63.254126.18.63.25516,382
74126.18.64.0/18126.18.64.1 to 126.18.127.254126.18.127.25516,382
75126.18.128.0/18126.18.128.1 to 126.18.191.254126.18.191.25516,382
76126.18.192.0/18126.18.192.1 to 126.18.255.254126.18.255.25516,382
77126.19.0.0/18126.19.0.1 to 126.19.63.254126.19.63.25516,382
78126.19.64.0/18126.19.64.1 to 126.19.127.254126.19.127.25516,382
79126.19.128.0/18126.19.128.1 to 126.19.191.254126.19.191.25516,382
80126.19.192.0/18126.19.192.1 to 126.19.255.254126.19.255.25516,382
81126.20.0.0/18126.20.0.1 to 126.20.63.254126.20.63.25516,382
82126.20.64.0/18126.20.64.1 to 126.20.127.254126.20.127.25516,382
83126.20.128.0/18126.20.128.1 to 126.20.191.254126.20.191.25516,382
84126.20.192.0/18126.20.192.1 to 126.20.255.254126.20.255.25516,382
85126.21.0.0/18126.21.0.1 to 126.21.63.254126.21.63.25516,382
86126.21.64.0/18126.21.64.1 to 126.21.127.254126.21.127.25516,382
87126.21.128.0/18126.21.128.1 to 126.21.191.254126.21.191.25516,382
88126.21.192.0/18126.21.192.1 to 126.21.255.254126.21.255.25516,382
89126.22.0.0/18126.22.0.1 to 126.22.63.254126.22.63.25516,382
90126.22.64.0/18126.22.64.1 to 126.22.127.254126.22.127.25516,382
91126.22.128.0/18126.22.128.1 to 126.22.191.254126.22.191.25516,382
92126.22.192.0/18126.22.192.1 to 126.22.255.254126.22.255.25516,382
93126.23.0.0/18126.23.0.1 to 126.23.63.254126.23.63.25516,382
94126.23.64.0/18126.23.64.1 to 126.23.127.254126.23.127.25516,382
95126.23.128.0/18126.23.128.1 to 126.23.191.254126.23.191.25516,382
96126.23.192.0/18126.23.192.1 to 126.23.255.254126.23.255.25516,382
97126.24.0.0/18126.24.0.1 to 126.24.63.254126.24.63.25516,382
98126.24.64.0/18126.24.64.1 to 126.24.127.254126.24.127.25516,382
99126.24.128.0/18126.24.128.1 to 126.24.191.254126.24.191.25516,382
100126.24.192.0/18126.24.192.1 to 126.24.255.254126.24.255.25516,382
101126.25.0.0/18126.25.0.1 to 126.25.63.254126.25.63.25516,382
102126.25.64.0/18126.25.64.1 to 126.25.127.254126.25.127.25516,382
103126.25.128.0/18126.25.128.1 to 126.25.191.254126.25.191.25516,382
104126.25.192.0/18126.25.192.1 to 126.25.255.254126.25.255.25516,382
105126.26.0.0/18126.26.0.1 to 126.26.63.254126.26.63.25516,382
106126.26.64.0/18126.26.64.1 to 126.26.127.254126.26.127.25516,382
107126.26.128.0/18126.26.128.1 to 126.26.191.254126.26.191.25516,382
108126.26.192.0/18126.26.192.1 to 126.26.255.254126.26.255.25516,382
109126.27.0.0/18126.27.0.1 to 126.27.63.254126.27.63.25516,382
110126.27.64.0/18126.27.64.1 to 126.27.127.254126.27.127.25516,382
111126.27.128.0/18126.27.128.1 to 126.27.191.254126.27.191.25516,382
112126.27.192.0/18126.27.192.1 to 126.27.255.254126.27.255.25516,382
113126.28.0.0/18126.28.0.1 to 126.28.63.254126.28.63.25516,382
114126.28.64.0/18126.28.64.1 to 126.28.127.254126.28.127.25516,382
115126.28.128.0/18126.28.128.1 to 126.28.191.254126.28.191.25516,382
116126.28.192.0/18126.28.192.1 to 126.28.255.254126.28.255.25516,382
117126.29.0.0/18126.29.0.1 to 126.29.63.254126.29.63.25516,382
118126.29.64.0/18126.29.64.1 to 126.29.127.254126.29.127.25516,382
119126.29.128.0/18126.29.128.1 to 126.29.191.254126.29.191.25516,382
120126.29.192.0/18126.29.192.1 to 126.29.255.254126.29.255.25516,382
121126.30.0.0/18126.30.0.1 to 126.30.63.254126.30.63.25516,382
122126.30.64.0/18126.30.64.1 to 126.30.127.254126.30.127.25516,382
123126.30.128.0/18126.30.128.1 to 126.30.191.254126.30.191.25516,382
124126.30.192.0/18126.30.192.1 to 126.30.255.254126.30.255.25516,382
125126.31.0.0/18126.31.0.1 to 126.31.63.254126.31.63.25516,382
126126.31.64.0/18126.31.64.1 to 126.31.127.254126.31.127.25516,382
127126.31.128.0/18126.31.128.1 to 126.31.191.254126.31.191.25516,382
128126.31.192.0/18126.31.192.1 to 126.31.255.254126.31.255.25516,382
129126.32.0.0/18126.32.0.1 to 126.32.63.254126.32.63.25516,382
130126.32.64.0/18126.32.64.1 to 126.32.127.254126.32.127.25516,382
131126.32.128.0/18126.32.128.1 to 126.32.191.254126.32.191.25516,382
132126.32.192.0/18126.32.192.1 to 126.32.255.254126.32.255.25516,382
133126.33.0.0/18126.33.0.1 to 126.33.63.254126.33.63.25516,382
134126.33.64.0/18126.33.64.1 to 126.33.127.254126.33.127.25516,382
135126.33.128.0/18126.33.128.1 to 126.33.191.254126.33.191.25516,382
136126.33.192.0/18126.33.192.1 to 126.33.255.254126.33.255.25516,382
137126.34.0.0/18126.34.0.1 to 126.34.63.254126.34.63.25516,382
138126.34.64.0/18126.34.64.1 to 126.34.127.254126.34.127.25516,382
139126.34.128.0/18126.34.128.1 to 126.34.191.254126.34.191.25516,382
140126.34.192.0/18126.34.192.1 to 126.34.255.254126.34.255.25516,382
141126.35.0.0/18126.35.0.1 to 126.35.63.254126.35.63.25516,382
142126.35.64.0/18126.35.64.1 to 126.35.127.254126.35.127.25516,382
143126.35.128.0/18126.35.128.1 to 126.35.191.254126.35.191.25516,382
144126.35.192.0/18126.35.192.1 to 126.35.255.254126.35.255.25516,382
145126.36.0.0/18126.36.0.1 to 126.36.63.254126.36.63.25516,382
146126.36.64.0/18126.36.64.1 to 126.36.127.254126.36.127.25516,382
147126.36.128.0/18126.36.128.1 to 126.36.191.254126.36.191.25516,382
148126.36.192.0/18126.36.192.1 to 126.36.255.254126.36.255.25516,382
149126.37.0.0/18126.37.0.1 to 126.37.63.254126.37.63.25516,382
150126.37.64.0/18126.37.64.1 to 126.37.127.254126.37.127.25516,382
151126.37.128.0/18126.37.128.1 to 126.37.191.254126.37.191.25516,382
152126.37.192.0/18126.37.192.1 to 126.37.255.254126.37.255.25516,382
153126.38.0.0/18126.38.0.1 to 126.38.63.254126.38.63.25516,382
154126.38.64.0/18126.38.64.1 to 126.38.127.254126.38.127.25516,382
155126.38.128.0/18126.38.128.1 to 126.38.191.254126.38.191.25516,382
156126.38.192.0/18126.38.192.1 to 126.38.255.254126.38.255.25516,382
157126.39.0.0/18126.39.0.1 to 126.39.63.254126.39.63.25516,382
158126.39.64.0/18126.39.64.1 to 126.39.127.254126.39.127.25516,382
159126.39.128.0/18126.39.128.1 to 126.39.191.254126.39.191.25516,382
160126.39.192.0/18126.39.192.1 to 126.39.255.254126.39.255.25516,382
161126.40.0.0/18126.40.0.1 to 126.40.63.254126.40.63.25516,382
162126.40.64.0/18126.40.64.1 to 126.40.127.254126.40.127.25516,382
163126.40.128.0/18126.40.128.1 to 126.40.191.254126.40.191.25516,382
164126.40.192.0/18126.40.192.1 to 126.40.255.254126.40.255.25516,382
165126.41.0.0/18126.41.0.1 to 126.41.63.254126.41.63.25516,382
166126.41.64.0/18126.41.64.1 to 126.41.127.254126.41.127.25516,382
167126.41.128.0/18126.41.128.1 to 126.41.191.254126.41.191.25516,382
168126.41.192.0/18126.41.192.1 to 126.41.255.254126.41.255.25516,382
169126.42.0.0/18126.42.0.1 to 126.42.63.254126.42.63.25516,382
170126.42.64.0/18126.42.64.1 to 126.42.127.254126.42.127.25516,382
171126.42.128.0/18126.42.128.1 to 126.42.191.254126.42.191.25516,382
172126.42.192.0/18126.42.192.1 to 126.42.255.254126.42.255.25516,382
173126.43.0.0/18126.43.0.1 to 126.43.63.254126.43.63.25516,382
174126.43.64.0/18126.43.64.1 to 126.43.127.254126.43.127.25516,382
175126.43.128.0/18126.43.128.1 to 126.43.191.254126.43.191.25516,382
176126.43.192.0/18126.43.192.1 to 126.43.255.254126.43.255.25516,382
177126.44.0.0/18126.44.0.1 to 126.44.63.254126.44.63.25516,382
178126.44.64.0/18126.44.64.1 to 126.44.127.254126.44.127.25516,382
179126.44.128.0/18126.44.128.1 to 126.44.191.254126.44.191.25516,382
180126.44.192.0/18126.44.192.1 to 126.44.255.254126.44.255.25516,382
181126.45.0.0/18126.45.0.1 to 126.45.63.254126.45.63.25516,382
182126.45.64.0/18126.45.64.1 to 126.45.127.254126.45.127.25516,382
183126.45.128.0/18126.45.128.1 to 126.45.191.254126.45.191.25516,382
184126.45.192.0/18126.45.192.1 to 126.45.255.254126.45.255.25516,382
185126.46.0.0/18126.46.0.1 to 126.46.63.254126.46.63.25516,382
186126.46.64.0/18126.46.64.1 to 126.46.127.254126.46.127.25516,382
187126.46.128.0/18126.46.128.1 to 126.46.191.254126.46.191.25516,382
188126.46.192.0/18126.46.192.1 to 126.46.255.254126.46.255.25516,382
189126.47.0.0/18126.47.0.1 to 126.47.63.254126.47.63.25516,382
190126.47.64.0/18126.47.64.1 to 126.47.127.254126.47.127.25516,382
191126.47.128.0/18126.47.128.1 to 126.47.191.254126.47.191.25516,382
192126.47.192.0/18126.47.192.1 to 126.47.255.254126.47.255.25516,382
193126.48.0.0/18126.48.0.1 to 126.48.63.254126.48.63.25516,382
194126.48.64.0/18126.48.64.1 to 126.48.127.254126.48.127.25516,382
195126.48.128.0/18126.48.128.1 to 126.48.191.254126.48.191.25516,382
196126.48.192.0/18126.48.192.1 to 126.48.255.254126.48.255.25516,382
197126.49.0.0/18126.49.0.1 to 126.49.63.254126.49.63.25516,382
198126.49.64.0/18126.49.64.1 to 126.49.127.254126.49.127.25516,382
199126.49.128.0/18126.49.128.1 to 126.49.191.254126.49.191.25516,382
200126.49.192.0/18126.49.192.1 to 126.49.255.254126.49.255.25516,382
201126.50.0.0/18126.50.0.1 to 126.50.63.254126.50.63.25516,382
202126.50.64.0/18126.50.64.1 to 126.50.127.254126.50.127.25516,382
203126.50.128.0/18126.50.128.1 to 126.50.191.254126.50.191.25516,382
204126.50.192.0/18126.50.192.1 to 126.50.255.254126.50.255.25516,382
205126.51.0.0/18126.51.0.1 to 126.51.63.254126.51.63.25516,382
206126.51.64.0/18126.51.64.1 to 126.51.127.254126.51.127.25516,382
207126.51.128.0/18126.51.128.1 to 126.51.191.254126.51.191.25516,382
208126.51.192.0/18126.51.192.1 to 126.51.255.254126.51.255.25516,382
209126.52.0.0/18126.52.0.1 to 126.52.63.254126.52.63.25516,382
210126.52.64.0/18126.52.64.1 to 126.52.127.254126.52.127.25516,382
211126.52.128.0/18126.52.128.1 to 126.52.191.254126.52.191.25516,382
212126.52.192.0/18126.52.192.1 to 126.52.255.254126.52.255.25516,382
213126.53.0.0/18126.53.0.1 to 126.53.63.254126.53.63.25516,382
214126.53.64.0/18126.53.64.1 to 126.53.127.254126.53.127.25516,382
215126.53.128.0/18126.53.128.1 to 126.53.191.254126.53.191.25516,382
216126.53.192.0/18126.53.192.1 to 126.53.255.254126.53.255.25516,382
217126.54.0.0/18126.54.0.1 to 126.54.63.254126.54.63.25516,382
218126.54.64.0/18126.54.64.1 to 126.54.127.254126.54.127.25516,382
219126.54.128.0/18126.54.128.1 to 126.54.191.254126.54.191.25516,382
220126.54.192.0/18126.54.192.1 to 126.54.255.254126.54.255.25516,382
221126.55.0.0/18126.55.0.1 to 126.55.63.254126.55.63.25516,382
222126.55.64.0/18126.55.64.1 to 126.55.127.254126.55.127.25516,382
223126.55.128.0/18126.55.128.1 to 126.55.191.254126.55.191.25516,382
224126.55.192.0/18126.55.192.1 to 126.55.255.254126.55.255.25516,382
225126.56.0.0/18126.56.0.1 to 126.56.63.254126.56.63.25516,382
226126.56.64.0/18126.56.64.1 to 126.56.127.254126.56.127.25516,382
227126.56.128.0/18126.56.128.1 to 126.56.191.254126.56.191.25516,382
228126.56.192.0/18126.56.192.1 to 126.56.255.254126.56.255.25516,382
229126.57.0.0/18126.57.0.1 to 126.57.63.254126.57.63.25516,382
230126.57.64.0/18126.57.64.1 to 126.57.127.254126.57.127.25516,382
231126.57.128.0/18126.57.128.1 to 126.57.191.254126.57.191.25516,382
232126.57.192.0/18126.57.192.1 to 126.57.255.254126.57.255.25516,382
233126.58.0.0/18126.58.0.1 to 126.58.63.254126.58.63.25516,382
234126.58.64.0/18126.58.64.1 to 126.58.127.254126.58.127.25516,382
235126.58.128.0/18126.58.128.1 to 126.58.191.254126.58.191.25516,382
236126.58.192.0/18126.58.192.1 to 126.58.255.254126.58.255.25516,382
237126.59.0.0/18126.59.0.1 to 126.59.63.254126.59.63.25516,382
238126.59.64.0/18126.59.64.1 to 126.59.127.254126.59.127.25516,382
239126.59.128.0/18126.59.128.1 to 126.59.191.254126.59.191.25516,382
240126.59.192.0/18126.59.192.1 to 126.59.255.254126.59.255.25516,382
241126.60.0.0/18126.60.0.1 to 126.60.63.254126.60.63.25516,382
242126.60.64.0/18126.60.64.1 to 126.60.127.254126.60.127.25516,382
243126.60.128.0/18126.60.128.1 to 126.60.191.254126.60.191.25516,382
244126.60.192.0/18126.60.192.1 to 126.60.255.254126.60.255.25516,382
245126.61.0.0/18126.61.0.1 to 126.61.63.254126.61.63.25516,382
246126.61.64.0/18126.61.64.1 to 126.61.127.254126.61.127.25516,382
247126.61.128.0/18126.61.128.1 to 126.61.191.254126.61.191.25516,382
248126.61.192.0/18126.61.192.1 to 126.61.255.254126.61.255.25516,382
249126.62.0.0/18126.62.0.1 to 126.62.63.254126.62.63.25516,382
250126.62.64.0/18126.62.64.1 to 126.62.127.254126.62.127.25516,382
251126.62.128.0/18126.62.128.1 to 126.62.191.254126.62.191.25516,382
252126.62.192.0/18126.62.192.1 to 126.62.255.254126.62.255.25516,382
253126.63.0.0/18126.63.0.1 to 126.63.63.254126.63.63.25516,382
254126.63.64.0/18126.63.64.1 to 126.63.127.254126.63.127.25516,382
255126.63.128.0/18126.63.128.1 to 126.63.191.254126.63.191.25516,382
256126.63.192.0/18126.63.192.1 to 126.63.255.254126.63.255.25516,382

IPv4 CIDR reference (/0 to /32)

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

IPv6 prefix reference

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

Private and special ranges

IPv4

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

IPv6

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

About this tool

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

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

Common questions

Why are two addresses lost in every IPv4 subnet?

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

What size of IPv6 network should a LAN use?

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

What is a wildcard mask?

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

Which ranges can I use inside an office?

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