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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.

Network208.0.0.0/7
Usable hosts33,554,430
Subnet mask254.0.0.0
Addresses33,554,432
Network address
208.0.0.0
Broadcast address
209.255.255.255
First usable
208.0.0.1
Last usable
209.255.255.254
Usable hosts
33,554,430 (33,554,432 less the network and broadcast addresses)
Subnet mask
254.0.0.0
Wildcard mask
1.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/7
Type
Public public
Old class
C (default /24)
As numbers
Hex D0000000 · Integer 3489660928 to 3523215359
Reverse DNS zones
208.in-addr.arpa
209.in-addr.arpa
/7 is not on a 8-bit boundary, so it takes 2 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11010000.00000000.00000000.00000000208.0.0.0
Subnet mask11111110.00000000.00000000.00000000254.0.0.0
Network11010000.00000000.00000000.00000000208.0.0.0
Broadcast11010001.11111111.11111111.11111111209.255.255.255
Split into smaller subnets/19
/8 (2)/9 (4)/10 (8)/11 (16)/12 (32)/13 (64)/14 (128)/15 (256)/16 (512)/17 (1,024)/18 (2,048)/19 (4,096)

208.0.0.0/7 makes 4,096 subnets of /19; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1208.0.0.0/19208.0.0.1 to 208.0.31.254208.0.31.2558,190
2208.0.32.0/19208.0.32.1 to 208.0.63.254208.0.63.2558,190
3208.0.64.0/19208.0.64.1 to 208.0.95.254208.0.95.2558,190
4208.0.96.0/19208.0.96.1 to 208.0.127.254208.0.127.2558,190
5208.0.128.0/19208.0.128.1 to 208.0.159.254208.0.159.2558,190
6208.0.160.0/19208.0.160.1 to 208.0.191.254208.0.191.2558,190
7208.0.192.0/19208.0.192.1 to 208.0.223.254208.0.223.2558,190
8208.0.224.0/19208.0.224.1 to 208.0.255.254208.0.255.2558,190
9208.1.0.0/19208.1.0.1 to 208.1.31.254208.1.31.2558,190
10208.1.32.0/19208.1.32.1 to 208.1.63.254208.1.63.2558,190
11208.1.64.0/19208.1.64.1 to 208.1.95.254208.1.95.2558,190
12208.1.96.0/19208.1.96.1 to 208.1.127.254208.1.127.2558,190
13208.1.128.0/19208.1.128.1 to 208.1.159.254208.1.159.2558,190
14208.1.160.0/19208.1.160.1 to 208.1.191.254208.1.191.2558,190
15208.1.192.0/19208.1.192.1 to 208.1.223.254208.1.223.2558,190
16208.1.224.0/19208.1.224.1 to 208.1.255.254208.1.255.2558,190
17208.2.0.0/19208.2.0.1 to 208.2.31.254208.2.31.2558,190
18208.2.32.0/19208.2.32.1 to 208.2.63.254208.2.63.2558,190
19208.2.64.0/19208.2.64.1 to 208.2.95.254208.2.95.2558,190
20208.2.96.0/19208.2.96.1 to 208.2.127.254208.2.127.2558,190
21208.2.128.0/19208.2.128.1 to 208.2.159.254208.2.159.2558,190
22208.2.160.0/19208.2.160.1 to 208.2.191.254208.2.191.2558,190
23208.2.192.0/19208.2.192.1 to 208.2.223.254208.2.223.2558,190
24208.2.224.0/19208.2.224.1 to 208.2.255.254208.2.255.2558,190
25208.3.0.0/19208.3.0.1 to 208.3.31.254208.3.31.2558,190
26208.3.32.0/19208.3.32.1 to 208.3.63.254208.3.63.2558,190
27208.3.64.0/19208.3.64.1 to 208.3.95.254208.3.95.2558,190
28208.3.96.0/19208.3.96.1 to 208.3.127.254208.3.127.2558,190
29208.3.128.0/19208.3.128.1 to 208.3.159.254208.3.159.2558,190
30208.3.160.0/19208.3.160.1 to 208.3.191.254208.3.191.2558,190
31208.3.192.0/19208.3.192.1 to 208.3.223.254208.3.223.2558,190
32208.3.224.0/19208.3.224.1 to 208.3.255.254208.3.255.2558,190
33208.4.0.0/19208.4.0.1 to 208.4.31.254208.4.31.2558,190
34208.4.32.0/19208.4.32.1 to 208.4.63.254208.4.63.2558,190
35208.4.64.0/19208.4.64.1 to 208.4.95.254208.4.95.2558,190
36208.4.96.0/19208.4.96.1 to 208.4.127.254208.4.127.2558,190
37208.4.128.0/19208.4.128.1 to 208.4.159.254208.4.159.2558,190
38208.4.160.0/19208.4.160.1 to 208.4.191.254208.4.191.2558,190
39208.4.192.0/19208.4.192.1 to 208.4.223.254208.4.223.2558,190
40208.4.224.0/19208.4.224.1 to 208.4.255.254208.4.255.2558,190
41208.5.0.0/19208.5.0.1 to 208.5.31.254208.5.31.2558,190
42208.5.32.0/19208.5.32.1 to 208.5.63.254208.5.63.2558,190
43208.5.64.0/19208.5.64.1 to 208.5.95.254208.5.95.2558,190
44208.5.96.0/19208.5.96.1 to 208.5.127.254208.5.127.2558,190
45208.5.128.0/19208.5.128.1 to 208.5.159.254208.5.159.2558,190
46208.5.160.0/19208.5.160.1 to 208.5.191.254208.5.191.2558,190
47208.5.192.0/19208.5.192.1 to 208.5.223.254208.5.223.2558,190
48208.5.224.0/19208.5.224.1 to 208.5.255.254208.5.255.2558,190
49208.6.0.0/19208.6.0.1 to 208.6.31.254208.6.31.2558,190
50208.6.32.0/19208.6.32.1 to 208.6.63.254208.6.63.2558,190
51208.6.64.0/19208.6.64.1 to 208.6.95.254208.6.95.2558,190
52208.6.96.0/19208.6.96.1 to 208.6.127.254208.6.127.2558,190
53208.6.128.0/19208.6.128.1 to 208.6.159.254208.6.159.2558,190
54208.6.160.0/19208.6.160.1 to 208.6.191.254208.6.191.2558,190
55208.6.192.0/19208.6.192.1 to 208.6.223.254208.6.223.2558,190
56208.6.224.0/19208.6.224.1 to 208.6.255.254208.6.255.2558,190
57208.7.0.0/19208.7.0.1 to 208.7.31.254208.7.31.2558,190
58208.7.32.0/19208.7.32.1 to 208.7.63.254208.7.63.2558,190
59208.7.64.0/19208.7.64.1 to 208.7.95.254208.7.95.2558,190
60208.7.96.0/19208.7.96.1 to 208.7.127.254208.7.127.2558,190
61208.7.128.0/19208.7.128.1 to 208.7.159.254208.7.159.2558,190
62208.7.160.0/19208.7.160.1 to 208.7.191.254208.7.191.2558,190
63208.7.192.0/19208.7.192.1 to 208.7.223.254208.7.223.2558,190
64208.7.224.0/19208.7.224.1 to 208.7.255.254208.7.255.2558,190
65208.8.0.0/19208.8.0.1 to 208.8.31.254208.8.31.2558,190
66208.8.32.0/19208.8.32.1 to 208.8.63.254208.8.63.2558,190
67208.8.64.0/19208.8.64.1 to 208.8.95.254208.8.95.2558,190
68208.8.96.0/19208.8.96.1 to 208.8.127.254208.8.127.2558,190
69208.8.128.0/19208.8.128.1 to 208.8.159.254208.8.159.2558,190
70208.8.160.0/19208.8.160.1 to 208.8.191.254208.8.191.2558,190
71208.8.192.0/19208.8.192.1 to 208.8.223.254208.8.223.2558,190
72208.8.224.0/19208.8.224.1 to 208.8.255.254208.8.255.2558,190
73208.9.0.0/19208.9.0.1 to 208.9.31.254208.9.31.2558,190
74208.9.32.0/19208.9.32.1 to 208.9.63.254208.9.63.2558,190
75208.9.64.0/19208.9.64.1 to 208.9.95.254208.9.95.2558,190
76208.9.96.0/19208.9.96.1 to 208.9.127.254208.9.127.2558,190
77208.9.128.0/19208.9.128.1 to 208.9.159.254208.9.159.2558,190
78208.9.160.0/19208.9.160.1 to 208.9.191.254208.9.191.2558,190
79208.9.192.0/19208.9.192.1 to 208.9.223.254208.9.223.2558,190
80208.9.224.0/19208.9.224.1 to 208.9.255.254208.9.255.2558,190
81208.10.0.0/19208.10.0.1 to 208.10.31.254208.10.31.2558,190
82208.10.32.0/19208.10.32.1 to 208.10.63.254208.10.63.2558,190
83208.10.64.0/19208.10.64.1 to 208.10.95.254208.10.95.2558,190
84208.10.96.0/19208.10.96.1 to 208.10.127.254208.10.127.2558,190
85208.10.128.0/19208.10.128.1 to 208.10.159.254208.10.159.2558,190
86208.10.160.0/19208.10.160.1 to 208.10.191.254208.10.191.2558,190
87208.10.192.0/19208.10.192.1 to 208.10.223.254208.10.223.2558,190
88208.10.224.0/19208.10.224.1 to 208.10.255.254208.10.255.2558,190
89208.11.0.0/19208.11.0.1 to 208.11.31.254208.11.31.2558,190
90208.11.32.0/19208.11.32.1 to 208.11.63.254208.11.63.2558,190
91208.11.64.0/19208.11.64.1 to 208.11.95.254208.11.95.2558,190
92208.11.96.0/19208.11.96.1 to 208.11.127.254208.11.127.2558,190
93208.11.128.0/19208.11.128.1 to 208.11.159.254208.11.159.2558,190
94208.11.160.0/19208.11.160.1 to 208.11.191.254208.11.191.2558,190
95208.11.192.0/19208.11.192.1 to 208.11.223.254208.11.223.2558,190
96208.11.224.0/19208.11.224.1 to 208.11.255.254208.11.255.2558,190
97208.12.0.0/19208.12.0.1 to 208.12.31.254208.12.31.2558,190
98208.12.32.0/19208.12.32.1 to 208.12.63.254208.12.63.2558,190
99208.12.64.0/19208.12.64.1 to 208.12.95.254208.12.95.2558,190
100208.12.96.0/19208.12.96.1 to 208.12.127.254208.12.127.2558,190
101208.12.128.0/19208.12.128.1 to 208.12.159.254208.12.159.2558,190
102208.12.160.0/19208.12.160.1 to 208.12.191.254208.12.191.2558,190
103208.12.192.0/19208.12.192.1 to 208.12.223.254208.12.223.2558,190
104208.12.224.0/19208.12.224.1 to 208.12.255.254208.12.255.2558,190
105208.13.0.0/19208.13.0.1 to 208.13.31.254208.13.31.2558,190
106208.13.32.0/19208.13.32.1 to 208.13.63.254208.13.63.2558,190
107208.13.64.0/19208.13.64.1 to 208.13.95.254208.13.95.2558,190
108208.13.96.0/19208.13.96.1 to 208.13.127.254208.13.127.2558,190
109208.13.128.0/19208.13.128.1 to 208.13.159.254208.13.159.2558,190
110208.13.160.0/19208.13.160.1 to 208.13.191.254208.13.191.2558,190
111208.13.192.0/19208.13.192.1 to 208.13.223.254208.13.223.2558,190
112208.13.224.0/19208.13.224.1 to 208.13.255.254208.13.255.2558,190
113208.14.0.0/19208.14.0.1 to 208.14.31.254208.14.31.2558,190
114208.14.32.0/19208.14.32.1 to 208.14.63.254208.14.63.2558,190
115208.14.64.0/19208.14.64.1 to 208.14.95.254208.14.95.2558,190
116208.14.96.0/19208.14.96.1 to 208.14.127.254208.14.127.2558,190
117208.14.128.0/19208.14.128.1 to 208.14.159.254208.14.159.2558,190
118208.14.160.0/19208.14.160.1 to 208.14.191.254208.14.191.2558,190
119208.14.192.0/19208.14.192.1 to 208.14.223.254208.14.223.2558,190
120208.14.224.0/19208.14.224.1 to 208.14.255.254208.14.255.2558,190
121208.15.0.0/19208.15.0.1 to 208.15.31.254208.15.31.2558,190
122208.15.32.0/19208.15.32.1 to 208.15.63.254208.15.63.2558,190
123208.15.64.0/19208.15.64.1 to 208.15.95.254208.15.95.2558,190
124208.15.96.0/19208.15.96.1 to 208.15.127.254208.15.127.2558,190
125208.15.128.0/19208.15.128.1 to 208.15.159.254208.15.159.2558,190
126208.15.160.0/19208.15.160.1 to 208.15.191.254208.15.191.2558,190
127208.15.192.0/19208.15.192.1 to 208.15.223.254208.15.223.2558,190
128208.15.224.0/19208.15.224.1 to 208.15.255.254208.15.255.2558,190
129208.16.0.0/19208.16.0.1 to 208.16.31.254208.16.31.2558,190
130208.16.32.0/19208.16.32.1 to 208.16.63.254208.16.63.2558,190
131208.16.64.0/19208.16.64.1 to 208.16.95.254208.16.95.2558,190
132208.16.96.0/19208.16.96.1 to 208.16.127.254208.16.127.2558,190
133208.16.128.0/19208.16.128.1 to 208.16.159.254208.16.159.2558,190
134208.16.160.0/19208.16.160.1 to 208.16.191.254208.16.191.2558,190
135208.16.192.0/19208.16.192.1 to 208.16.223.254208.16.223.2558,190
136208.16.224.0/19208.16.224.1 to 208.16.255.254208.16.255.2558,190
137208.17.0.0/19208.17.0.1 to 208.17.31.254208.17.31.2558,190
138208.17.32.0/19208.17.32.1 to 208.17.63.254208.17.63.2558,190
139208.17.64.0/19208.17.64.1 to 208.17.95.254208.17.95.2558,190
140208.17.96.0/19208.17.96.1 to 208.17.127.254208.17.127.2558,190
141208.17.128.0/19208.17.128.1 to 208.17.159.254208.17.159.2558,190
142208.17.160.0/19208.17.160.1 to 208.17.191.254208.17.191.2558,190
143208.17.192.0/19208.17.192.1 to 208.17.223.254208.17.223.2558,190
144208.17.224.0/19208.17.224.1 to 208.17.255.254208.17.255.2558,190
145208.18.0.0/19208.18.0.1 to 208.18.31.254208.18.31.2558,190
146208.18.32.0/19208.18.32.1 to 208.18.63.254208.18.63.2558,190
147208.18.64.0/19208.18.64.1 to 208.18.95.254208.18.95.2558,190
148208.18.96.0/19208.18.96.1 to 208.18.127.254208.18.127.2558,190
149208.18.128.0/19208.18.128.1 to 208.18.159.254208.18.159.2558,190
150208.18.160.0/19208.18.160.1 to 208.18.191.254208.18.191.2558,190
151208.18.192.0/19208.18.192.1 to 208.18.223.254208.18.223.2558,190
152208.18.224.0/19208.18.224.1 to 208.18.255.254208.18.255.2558,190
153208.19.0.0/19208.19.0.1 to 208.19.31.254208.19.31.2558,190
154208.19.32.0/19208.19.32.1 to 208.19.63.254208.19.63.2558,190
155208.19.64.0/19208.19.64.1 to 208.19.95.254208.19.95.2558,190
156208.19.96.0/19208.19.96.1 to 208.19.127.254208.19.127.2558,190
157208.19.128.0/19208.19.128.1 to 208.19.159.254208.19.159.2558,190
158208.19.160.0/19208.19.160.1 to 208.19.191.254208.19.191.2558,190
159208.19.192.0/19208.19.192.1 to 208.19.223.254208.19.223.2558,190
160208.19.224.0/19208.19.224.1 to 208.19.255.254208.19.255.2558,190
161208.20.0.0/19208.20.0.1 to 208.20.31.254208.20.31.2558,190
162208.20.32.0/19208.20.32.1 to 208.20.63.254208.20.63.2558,190
163208.20.64.0/19208.20.64.1 to 208.20.95.254208.20.95.2558,190
164208.20.96.0/19208.20.96.1 to 208.20.127.254208.20.127.2558,190
165208.20.128.0/19208.20.128.1 to 208.20.159.254208.20.159.2558,190
166208.20.160.0/19208.20.160.1 to 208.20.191.254208.20.191.2558,190
167208.20.192.0/19208.20.192.1 to 208.20.223.254208.20.223.2558,190
168208.20.224.0/19208.20.224.1 to 208.20.255.254208.20.255.2558,190
169208.21.0.0/19208.21.0.1 to 208.21.31.254208.21.31.2558,190
170208.21.32.0/19208.21.32.1 to 208.21.63.254208.21.63.2558,190
171208.21.64.0/19208.21.64.1 to 208.21.95.254208.21.95.2558,190
172208.21.96.0/19208.21.96.1 to 208.21.127.254208.21.127.2558,190
173208.21.128.0/19208.21.128.1 to 208.21.159.254208.21.159.2558,190
174208.21.160.0/19208.21.160.1 to 208.21.191.254208.21.191.2558,190
175208.21.192.0/19208.21.192.1 to 208.21.223.254208.21.223.2558,190
176208.21.224.0/19208.21.224.1 to 208.21.255.254208.21.255.2558,190
177208.22.0.0/19208.22.0.1 to 208.22.31.254208.22.31.2558,190
178208.22.32.0/19208.22.32.1 to 208.22.63.254208.22.63.2558,190
179208.22.64.0/19208.22.64.1 to 208.22.95.254208.22.95.2558,190
180208.22.96.0/19208.22.96.1 to 208.22.127.254208.22.127.2558,190
181208.22.128.0/19208.22.128.1 to 208.22.159.254208.22.159.2558,190
182208.22.160.0/19208.22.160.1 to 208.22.191.254208.22.191.2558,190
183208.22.192.0/19208.22.192.1 to 208.22.223.254208.22.223.2558,190
184208.22.224.0/19208.22.224.1 to 208.22.255.254208.22.255.2558,190
185208.23.0.0/19208.23.0.1 to 208.23.31.254208.23.31.2558,190
186208.23.32.0/19208.23.32.1 to 208.23.63.254208.23.63.2558,190
187208.23.64.0/19208.23.64.1 to 208.23.95.254208.23.95.2558,190
188208.23.96.0/19208.23.96.1 to 208.23.127.254208.23.127.2558,190
189208.23.128.0/19208.23.128.1 to 208.23.159.254208.23.159.2558,190
190208.23.160.0/19208.23.160.1 to 208.23.191.254208.23.191.2558,190
191208.23.192.0/19208.23.192.1 to 208.23.223.254208.23.223.2558,190
192208.23.224.0/19208.23.224.1 to 208.23.255.254208.23.255.2558,190
193208.24.0.0/19208.24.0.1 to 208.24.31.254208.24.31.2558,190
194208.24.32.0/19208.24.32.1 to 208.24.63.254208.24.63.2558,190
195208.24.64.0/19208.24.64.1 to 208.24.95.254208.24.95.2558,190
196208.24.96.0/19208.24.96.1 to 208.24.127.254208.24.127.2558,190
197208.24.128.0/19208.24.128.1 to 208.24.159.254208.24.159.2558,190
198208.24.160.0/19208.24.160.1 to 208.24.191.254208.24.191.2558,190
199208.24.192.0/19208.24.192.1 to 208.24.223.254208.24.223.2558,190
200208.24.224.0/19208.24.224.1 to 208.24.255.254208.24.255.2558,190
201208.25.0.0/19208.25.0.1 to 208.25.31.254208.25.31.2558,190
202208.25.32.0/19208.25.32.1 to 208.25.63.254208.25.63.2558,190
203208.25.64.0/19208.25.64.1 to 208.25.95.254208.25.95.2558,190
204208.25.96.0/19208.25.96.1 to 208.25.127.254208.25.127.2558,190
205208.25.128.0/19208.25.128.1 to 208.25.159.254208.25.159.2558,190
206208.25.160.0/19208.25.160.1 to 208.25.191.254208.25.191.2558,190
207208.25.192.0/19208.25.192.1 to 208.25.223.254208.25.223.2558,190
208208.25.224.0/19208.25.224.1 to 208.25.255.254208.25.255.2558,190
209208.26.0.0/19208.26.0.1 to 208.26.31.254208.26.31.2558,190
210208.26.32.0/19208.26.32.1 to 208.26.63.254208.26.63.2558,190
211208.26.64.0/19208.26.64.1 to 208.26.95.254208.26.95.2558,190
212208.26.96.0/19208.26.96.1 to 208.26.127.254208.26.127.2558,190
213208.26.128.0/19208.26.128.1 to 208.26.159.254208.26.159.2558,190
214208.26.160.0/19208.26.160.1 to 208.26.191.254208.26.191.2558,190
215208.26.192.0/19208.26.192.1 to 208.26.223.254208.26.223.2558,190
216208.26.224.0/19208.26.224.1 to 208.26.255.254208.26.255.2558,190
217208.27.0.0/19208.27.0.1 to 208.27.31.254208.27.31.2558,190
218208.27.32.0/19208.27.32.1 to 208.27.63.254208.27.63.2558,190
219208.27.64.0/19208.27.64.1 to 208.27.95.254208.27.95.2558,190
220208.27.96.0/19208.27.96.1 to 208.27.127.254208.27.127.2558,190
221208.27.128.0/19208.27.128.1 to 208.27.159.254208.27.159.2558,190
222208.27.160.0/19208.27.160.1 to 208.27.191.254208.27.191.2558,190
223208.27.192.0/19208.27.192.1 to 208.27.223.254208.27.223.2558,190
224208.27.224.0/19208.27.224.1 to 208.27.255.254208.27.255.2558,190
225208.28.0.0/19208.28.0.1 to 208.28.31.254208.28.31.2558,190
226208.28.32.0/19208.28.32.1 to 208.28.63.254208.28.63.2558,190
227208.28.64.0/19208.28.64.1 to 208.28.95.254208.28.95.2558,190
228208.28.96.0/19208.28.96.1 to 208.28.127.254208.28.127.2558,190
229208.28.128.0/19208.28.128.1 to 208.28.159.254208.28.159.2558,190
230208.28.160.0/19208.28.160.1 to 208.28.191.254208.28.191.2558,190
231208.28.192.0/19208.28.192.1 to 208.28.223.254208.28.223.2558,190
232208.28.224.0/19208.28.224.1 to 208.28.255.254208.28.255.2558,190
233208.29.0.0/19208.29.0.1 to 208.29.31.254208.29.31.2558,190
234208.29.32.0/19208.29.32.1 to 208.29.63.254208.29.63.2558,190
235208.29.64.0/19208.29.64.1 to 208.29.95.254208.29.95.2558,190
236208.29.96.0/19208.29.96.1 to 208.29.127.254208.29.127.2558,190
237208.29.128.0/19208.29.128.1 to 208.29.159.254208.29.159.2558,190
238208.29.160.0/19208.29.160.1 to 208.29.191.254208.29.191.2558,190
239208.29.192.0/19208.29.192.1 to 208.29.223.254208.29.223.2558,190
240208.29.224.0/19208.29.224.1 to 208.29.255.254208.29.255.2558,190
241208.30.0.0/19208.30.0.1 to 208.30.31.254208.30.31.2558,190
242208.30.32.0/19208.30.32.1 to 208.30.63.254208.30.63.2558,190
243208.30.64.0/19208.30.64.1 to 208.30.95.254208.30.95.2558,190
244208.30.96.0/19208.30.96.1 to 208.30.127.254208.30.127.2558,190
245208.30.128.0/19208.30.128.1 to 208.30.159.254208.30.159.2558,190
246208.30.160.0/19208.30.160.1 to 208.30.191.254208.30.191.2558,190
247208.30.192.0/19208.30.192.1 to 208.30.223.254208.30.223.2558,190
248208.30.224.0/19208.30.224.1 to 208.30.255.254208.30.255.2558,190
249208.31.0.0/19208.31.0.1 to 208.31.31.254208.31.31.2558,190
250208.31.32.0/19208.31.32.1 to 208.31.63.254208.31.63.2558,190
251208.31.64.0/19208.31.64.1 to 208.31.95.254208.31.95.2558,190
252208.31.96.0/19208.31.96.1 to 208.31.127.254208.31.127.2558,190
253208.31.128.0/19208.31.128.1 to 208.31.159.254208.31.159.2558,190
254208.31.160.0/19208.31.160.1 to 208.31.191.254208.31.191.2558,190
255208.31.192.0/19208.31.192.1 to 208.31.223.254208.31.223.2558,190
256208.31.224.0/19208.31.224.1 to 208.31.255.254208.31.255.2558,190

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.