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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.

Network254.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
254.0.0.0
Broadcast address
254.255.255.255
First usable
254.0.0.1
Last usable
254.255.255.254
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
Reserved 240.0.0.0/4
Future use; not usable on most systems
Old class
E (reserved)
As numbers
Hex FE000000 · Integer 4261412864 to 4278190079
Reverse DNS zone
254.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11111110..00000000.00000000.00000000254.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network11111110..00000000.00000000.00000000254.0.0.0
Broadcast11111110..11111111.11111111.11111111254.255.255.255
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)

254.0.0.0/8 makes 4,096 subnets of /20; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1254.0.0.0/20254.0.0.1 to 254.0.15.254254.0.15.2554,094
2254.0.16.0/20254.0.16.1 to 254.0.31.254254.0.31.2554,094
3254.0.32.0/20254.0.32.1 to 254.0.47.254254.0.47.2554,094
4254.0.48.0/20254.0.48.1 to 254.0.63.254254.0.63.2554,094
5254.0.64.0/20254.0.64.1 to 254.0.79.254254.0.79.2554,094
6254.0.80.0/20254.0.80.1 to 254.0.95.254254.0.95.2554,094
7254.0.96.0/20254.0.96.1 to 254.0.111.254254.0.111.2554,094
8254.0.112.0/20254.0.112.1 to 254.0.127.254254.0.127.2554,094
9254.0.128.0/20254.0.128.1 to 254.0.143.254254.0.143.2554,094
10254.0.144.0/20254.0.144.1 to 254.0.159.254254.0.159.2554,094
11254.0.160.0/20254.0.160.1 to 254.0.175.254254.0.175.2554,094
12254.0.176.0/20254.0.176.1 to 254.0.191.254254.0.191.2554,094
13254.0.192.0/20254.0.192.1 to 254.0.207.254254.0.207.2554,094
14254.0.208.0/20254.0.208.1 to 254.0.223.254254.0.223.2554,094
15254.0.224.0/20254.0.224.1 to 254.0.239.254254.0.239.2554,094
16254.0.240.0/20254.0.240.1 to 254.0.255.254254.0.255.2554,094
17254.1.0.0/20254.1.0.1 to 254.1.15.254254.1.15.2554,094
18254.1.16.0/20254.1.16.1 to 254.1.31.254254.1.31.2554,094
19254.1.32.0/20254.1.32.1 to 254.1.47.254254.1.47.2554,094
20254.1.48.0/20254.1.48.1 to 254.1.63.254254.1.63.2554,094
21254.1.64.0/20254.1.64.1 to 254.1.79.254254.1.79.2554,094
22254.1.80.0/20254.1.80.1 to 254.1.95.254254.1.95.2554,094
23254.1.96.0/20254.1.96.1 to 254.1.111.254254.1.111.2554,094
24254.1.112.0/20254.1.112.1 to 254.1.127.254254.1.127.2554,094
25254.1.128.0/20254.1.128.1 to 254.1.143.254254.1.143.2554,094
26254.1.144.0/20254.1.144.1 to 254.1.159.254254.1.159.2554,094
27254.1.160.0/20254.1.160.1 to 254.1.175.254254.1.175.2554,094
28254.1.176.0/20254.1.176.1 to 254.1.191.254254.1.191.2554,094
29254.1.192.0/20254.1.192.1 to 254.1.207.254254.1.207.2554,094
30254.1.208.0/20254.1.208.1 to 254.1.223.254254.1.223.2554,094
31254.1.224.0/20254.1.224.1 to 254.1.239.254254.1.239.2554,094
32254.1.240.0/20254.1.240.1 to 254.1.255.254254.1.255.2554,094
33254.2.0.0/20254.2.0.1 to 254.2.15.254254.2.15.2554,094
34254.2.16.0/20254.2.16.1 to 254.2.31.254254.2.31.2554,094
35254.2.32.0/20254.2.32.1 to 254.2.47.254254.2.47.2554,094
36254.2.48.0/20254.2.48.1 to 254.2.63.254254.2.63.2554,094
37254.2.64.0/20254.2.64.1 to 254.2.79.254254.2.79.2554,094
38254.2.80.0/20254.2.80.1 to 254.2.95.254254.2.95.2554,094
39254.2.96.0/20254.2.96.1 to 254.2.111.254254.2.111.2554,094
40254.2.112.0/20254.2.112.1 to 254.2.127.254254.2.127.2554,094
41254.2.128.0/20254.2.128.1 to 254.2.143.254254.2.143.2554,094
42254.2.144.0/20254.2.144.1 to 254.2.159.254254.2.159.2554,094
43254.2.160.0/20254.2.160.1 to 254.2.175.254254.2.175.2554,094
44254.2.176.0/20254.2.176.1 to 254.2.191.254254.2.191.2554,094
45254.2.192.0/20254.2.192.1 to 254.2.207.254254.2.207.2554,094
46254.2.208.0/20254.2.208.1 to 254.2.223.254254.2.223.2554,094
47254.2.224.0/20254.2.224.1 to 254.2.239.254254.2.239.2554,094
48254.2.240.0/20254.2.240.1 to 254.2.255.254254.2.255.2554,094
49254.3.0.0/20254.3.0.1 to 254.3.15.254254.3.15.2554,094
50254.3.16.0/20254.3.16.1 to 254.3.31.254254.3.31.2554,094
51254.3.32.0/20254.3.32.1 to 254.3.47.254254.3.47.2554,094
52254.3.48.0/20254.3.48.1 to 254.3.63.254254.3.63.2554,094
53254.3.64.0/20254.3.64.1 to 254.3.79.254254.3.79.2554,094
54254.3.80.0/20254.3.80.1 to 254.3.95.254254.3.95.2554,094
55254.3.96.0/20254.3.96.1 to 254.3.111.254254.3.111.2554,094
56254.3.112.0/20254.3.112.1 to 254.3.127.254254.3.127.2554,094
57254.3.128.0/20254.3.128.1 to 254.3.143.254254.3.143.2554,094
58254.3.144.0/20254.3.144.1 to 254.3.159.254254.3.159.2554,094
59254.3.160.0/20254.3.160.1 to 254.3.175.254254.3.175.2554,094
60254.3.176.0/20254.3.176.1 to 254.3.191.254254.3.191.2554,094
61254.3.192.0/20254.3.192.1 to 254.3.207.254254.3.207.2554,094
62254.3.208.0/20254.3.208.1 to 254.3.223.254254.3.223.2554,094
63254.3.224.0/20254.3.224.1 to 254.3.239.254254.3.239.2554,094
64254.3.240.0/20254.3.240.1 to 254.3.255.254254.3.255.2554,094
65254.4.0.0/20254.4.0.1 to 254.4.15.254254.4.15.2554,094
66254.4.16.0/20254.4.16.1 to 254.4.31.254254.4.31.2554,094
67254.4.32.0/20254.4.32.1 to 254.4.47.254254.4.47.2554,094
68254.4.48.0/20254.4.48.1 to 254.4.63.254254.4.63.2554,094
69254.4.64.0/20254.4.64.1 to 254.4.79.254254.4.79.2554,094
70254.4.80.0/20254.4.80.1 to 254.4.95.254254.4.95.2554,094
71254.4.96.0/20254.4.96.1 to 254.4.111.254254.4.111.2554,094
72254.4.112.0/20254.4.112.1 to 254.4.127.254254.4.127.2554,094
73254.4.128.0/20254.4.128.1 to 254.4.143.254254.4.143.2554,094
74254.4.144.0/20254.4.144.1 to 254.4.159.254254.4.159.2554,094
75254.4.160.0/20254.4.160.1 to 254.4.175.254254.4.175.2554,094
76254.4.176.0/20254.4.176.1 to 254.4.191.254254.4.191.2554,094
77254.4.192.0/20254.4.192.1 to 254.4.207.254254.4.207.2554,094
78254.4.208.0/20254.4.208.1 to 254.4.223.254254.4.223.2554,094
79254.4.224.0/20254.4.224.1 to 254.4.239.254254.4.239.2554,094
80254.4.240.0/20254.4.240.1 to 254.4.255.254254.4.255.2554,094
81254.5.0.0/20254.5.0.1 to 254.5.15.254254.5.15.2554,094
82254.5.16.0/20254.5.16.1 to 254.5.31.254254.5.31.2554,094
83254.5.32.0/20254.5.32.1 to 254.5.47.254254.5.47.2554,094
84254.5.48.0/20254.5.48.1 to 254.5.63.254254.5.63.2554,094
85254.5.64.0/20254.5.64.1 to 254.5.79.254254.5.79.2554,094
86254.5.80.0/20254.5.80.1 to 254.5.95.254254.5.95.2554,094
87254.5.96.0/20254.5.96.1 to 254.5.111.254254.5.111.2554,094
88254.5.112.0/20254.5.112.1 to 254.5.127.254254.5.127.2554,094
89254.5.128.0/20254.5.128.1 to 254.5.143.254254.5.143.2554,094
90254.5.144.0/20254.5.144.1 to 254.5.159.254254.5.159.2554,094
91254.5.160.0/20254.5.160.1 to 254.5.175.254254.5.175.2554,094
92254.5.176.0/20254.5.176.1 to 254.5.191.254254.5.191.2554,094
93254.5.192.0/20254.5.192.1 to 254.5.207.254254.5.207.2554,094
94254.5.208.0/20254.5.208.1 to 254.5.223.254254.5.223.2554,094
95254.5.224.0/20254.5.224.1 to 254.5.239.254254.5.239.2554,094
96254.5.240.0/20254.5.240.1 to 254.5.255.254254.5.255.2554,094
97254.6.0.0/20254.6.0.1 to 254.6.15.254254.6.15.2554,094
98254.6.16.0/20254.6.16.1 to 254.6.31.254254.6.31.2554,094
99254.6.32.0/20254.6.32.1 to 254.6.47.254254.6.47.2554,094
100254.6.48.0/20254.6.48.1 to 254.6.63.254254.6.63.2554,094
101254.6.64.0/20254.6.64.1 to 254.6.79.254254.6.79.2554,094
102254.6.80.0/20254.6.80.1 to 254.6.95.254254.6.95.2554,094
103254.6.96.0/20254.6.96.1 to 254.6.111.254254.6.111.2554,094
104254.6.112.0/20254.6.112.1 to 254.6.127.254254.6.127.2554,094
105254.6.128.0/20254.6.128.1 to 254.6.143.254254.6.143.2554,094
106254.6.144.0/20254.6.144.1 to 254.6.159.254254.6.159.2554,094
107254.6.160.0/20254.6.160.1 to 254.6.175.254254.6.175.2554,094
108254.6.176.0/20254.6.176.1 to 254.6.191.254254.6.191.2554,094
109254.6.192.0/20254.6.192.1 to 254.6.207.254254.6.207.2554,094
110254.6.208.0/20254.6.208.1 to 254.6.223.254254.6.223.2554,094
111254.6.224.0/20254.6.224.1 to 254.6.239.254254.6.239.2554,094
112254.6.240.0/20254.6.240.1 to 254.6.255.254254.6.255.2554,094
113254.7.0.0/20254.7.0.1 to 254.7.15.254254.7.15.2554,094
114254.7.16.0/20254.7.16.1 to 254.7.31.254254.7.31.2554,094
115254.7.32.0/20254.7.32.1 to 254.7.47.254254.7.47.2554,094
116254.7.48.0/20254.7.48.1 to 254.7.63.254254.7.63.2554,094
117254.7.64.0/20254.7.64.1 to 254.7.79.254254.7.79.2554,094
118254.7.80.0/20254.7.80.1 to 254.7.95.254254.7.95.2554,094
119254.7.96.0/20254.7.96.1 to 254.7.111.254254.7.111.2554,094
120254.7.112.0/20254.7.112.1 to 254.7.127.254254.7.127.2554,094
121254.7.128.0/20254.7.128.1 to 254.7.143.254254.7.143.2554,094
122254.7.144.0/20254.7.144.1 to 254.7.159.254254.7.159.2554,094
123254.7.160.0/20254.7.160.1 to 254.7.175.254254.7.175.2554,094
124254.7.176.0/20254.7.176.1 to 254.7.191.254254.7.191.2554,094
125254.7.192.0/20254.7.192.1 to 254.7.207.254254.7.207.2554,094
126254.7.208.0/20254.7.208.1 to 254.7.223.254254.7.223.2554,094
127254.7.224.0/20254.7.224.1 to 254.7.239.254254.7.239.2554,094
128254.7.240.0/20254.7.240.1 to 254.7.255.254254.7.255.2554,094
129254.8.0.0/20254.8.0.1 to 254.8.15.254254.8.15.2554,094
130254.8.16.0/20254.8.16.1 to 254.8.31.254254.8.31.2554,094
131254.8.32.0/20254.8.32.1 to 254.8.47.254254.8.47.2554,094
132254.8.48.0/20254.8.48.1 to 254.8.63.254254.8.63.2554,094
133254.8.64.0/20254.8.64.1 to 254.8.79.254254.8.79.2554,094
134254.8.80.0/20254.8.80.1 to 254.8.95.254254.8.95.2554,094
135254.8.96.0/20254.8.96.1 to 254.8.111.254254.8.111.2554,094
136254.8.112.0/20254.8.112.1 to 254.8.127.254254.8.127.2554,094
137254.8.128.0/20254.8.128.1 to 254.8.143.254254.8.143.2554,094
138254.8.144.0/20254.8.144.1 to 254.8.159.254254.8.159.2554,094
139254.8.160.0/20254.8.160.1 to 254.8.175.254254.8.175.2554,094
140254.8.176.0/20254.8.176.1 to 254.8.191.254254.8.191.2554,094
141254.8.192.0/20254.8.192.1 to 254.8.207.254254.8.207.2554,094
142254.8.208.0/20254.8.208.1 to 254.8.223.254254.8.223.2554,094
143254.8.224.0/20254.8.224.1 to 254.8.239.254254.8.239.2554,094
144254.8.240.0/20254.8.240.1 to 254.8.255.254254.8.255.2554,094
145254.9.0.0/20254.9.0.1 to 254.9.15.254254.9.15.2554,094
146254.9.16.0/20254.9.16.1 to 254.9.31.254254.9.31.2554,094
147254.9.32.0/20254.9.32.1 to 254.9.47.254254.9.47.2554,094
148254.9.48.0/20254.9.48.1 to 254.9.63.254254.9.63.2554,094
149254.9.64.0/20254.9.64.1 to 254.9.79.254254.9.79.2554,094
150254.9.80.0/20254.9.80.1 to 254.9.95.254254.9.95.2554,094
151254.9.96.0/20254.9.96.1 to 254.9.111.254254.9.111.2554,094
152254.9.112.0/20254.9.112.1 to 254.9.127.254254.9.127.2554,094
153254.9.128.0/20254.9.128.1 to 254.9.143.254254.9.143.2554,094
154254.9.144.0/20254.9.144.1 to 254.9.159.254254.9.159.2554,094
155254.9.160.0/20254.9.160.1 to 254.9.175.254254.9.175.2554,094
156254.9.176.0/20254.9.176.1 to 254.9.191.254254.9.191.2554,094
157254.9.192.0/20254.9.192.1 to 254.9.207.254254.9.207.2554,094
158254.9.208.0/20254.9.208.1 to 254.9.223.254254.9.223.2554,094
159254.9.224.0/20254.9.224.1 to 254.9.239.254254.9.239.2554,094
160254.9.240.0/20254.9.240.1 to 254.9.255.254254.9.255.2554,094
161254.10.0.0/20254.10.0.1 to 254.10.15.254254.10.15.2554,094
162254.10.16.0/20254.10.16.1 to 254.10.31.254254.10.31.2554,094
163254.10.32.0/20254.10.32.1 to 254.10.47.254254.10.47.2554,094
164254.10.48.0/20254.10.48.1 to 254.10.63.254254.10.63.2554,094
165254.10.64.0/20254.10.64.1 to 254.10.79.254254.10.79.2554,094
166254.10.80.0/20254.10.80.1 to 254.10.95.254254.10.95.2554,094
167254.10.96.0/20254.10.96.1 to 254.10.111.254254.10.111.2554,094
168254.10.112.0/20254.10.112.1 to 254.10.127.254254.10.127.2554,094
169254.10.128.0/20254.10.128.1 to 254.10.143.254254.10.143.2554,094
170254.10.144.0/20254.10.144.1 to 254.10.159.254254.10.159.2554,094
171254.10.160.0/20254.10.160.1 to 254.10.175.254254.10.175.2554,094
172254.10.176.0/20254.10.176.1 to 254.10.191.254254.10.191.2554,094
173254.10.192.0/20254.10.192.1 to 254.10.207.254254.10.207.2554,094
174254.10.208.0/20254.10.208.1 to 254.10.223.254254.10.223.2554,094
175254.10.224.0/20254.10.224.1 to 254.10.239.254254.10.239.2554,094
176254.10.240.0/20254.10.240.1 to 254.10.255.254254.10.255.2554,094
177254.11.0.0/20254.11.0.1 to 254.11.15.254254.11.15.2554,094
178254.11.16.0/20254.11.16.1 to 254.11.31.254254.11.31.2554,094
179254.11.32.0/20254.11.32.1 to 254.11.47.254254.11.47.2554,094
180254.11.48.0/20254.11.48.1 to 254.11.63.254254.11.63.2554,094
181254.11.64.0/20254.11.64.1 to 254.11.79.254254.11.79.2554,094
182254.11.80.0/20254.11.80.1 to 254.11.95.254254.11.95.2554,094
183254.11.96.0/20254.11.96.1 to 254.11.111.254254.11.111.2554,094
184254.11.112.0/20254.11.112.1 to 254.11.127.254254.11.127.2554,094
185254.11.128.0/20254.11.128.1 to 254.11.143.254254.11.143.2554,094
186254.11.144.0/20254.11.144.1 to 254.11.159.254254.11.159.2554,094
187254.11.160.0/20254.11.160.1 to 254.11.175.254254.11.175.2554,094
188254.11.176.0/20254.11.176.1 to 254.11.191.254254.11.191.2554,094
189254.11.192.0/20254.11.192.1 to 254.11.207.254254.11.207.2554,094
190254.11.208.0/20254.11.208.1 to 254.11.223.254254.11.223.2554,094
191254.11.224.0/20254.11.224.1 to 254.11.239.254254.11.239.2554,094
192254.11.240.0/20254.11.240.1 to 254.11.255.254254.11.255.2554,094
193254.12.0.0/20254.12.0.1 to 254.12.15.254254.12.15.2554,094
194254.12.16.0/20254.12.16.1 to 254.12.31.254254.12.31.2554,094
195254.12.32.0/20254.12.32.1 to 254.12.47.254254.12.47.2554,094
196254.12.48.0/20254.12.48.1 to 254.12.63.254254.12.63.2554,094
197254.12.64.0/20254.12.64.1 to 254.12.79.254254.12.79.2554,094
198254.12.80.0/20254.12.80.1 to 254.12.95.254254.12.95.2554,094
199254.12.96.0/20254.12.96.1 to 254.12.111.254254.12.111.2554,094
200254.12.112.0/20254.12.112.1 to 254.12.127.254254.12.127.2554,094
201254.12.128.0/20254.12.128.1 to 254.12.143.254254.12.143.2554,094
202254.12.144.0/20254.12.144.1 to 254.12.159.254254.12.159.2554,094
203254.12.160.0/20254.12.160.1 to 254.12.175.254254.12.175.2554,094
204254.12.176.0/20254.12.176.1 to 254.12.191.254254.12.191.2554,094
205254.12.192.0/20254.12.192.1 to 254.12.207.254254.12.207.2554,094
206254.12.208.0/20254.12.208.1 to 254.12.223.254254.12.223.2554,094
207254.12.224.0/20254.12.224.1 to 254.12.239.254254.12.239.2554,094
208254.12.240.0/20254.12.240.1 to 254.12.255.254254.12.255.2554,094
209254.13.0.0/20254.13.0.1 to 254.13.15.254254.13.15.2554,094
210254.13.16.0/20254.13.16.1 to 254.13.31.254254.13.31.2554,094
211254.13.32.0/20254.13.32.1 to 254.13.47.254254.13.47.2554,094
212254.13.48.0/20254.13.48.1 to 254.13.63.254254.13.63.2554,094
213254.13.64.0/20254.13.64.1 to 254.13.79.254254.13.79.2554,094
214254.13.80.0/20254.13.80.1 to 254.13.95.254254.13.95.2554,094
215254.13.96.0/20254.13.96.1 to 254.13.111.254254.13.111.2554,094
216254.13.112.0/20254.13.112.1 to 254.13.127.254254.13.127.2554,094
217254.13.128.0/20254.13.128.1 to 254.13.143.254254.13.143.2554,094
218254.13.144.0/20254.13.144.1 to 254.13.159.254254.13.159.2554,094
219254.13.160.0/20254.13.160.1 to 254.13.175.254254.13.175.2554,094
220254.13.176.0/20254.13.176.1 to 254.13.191.254254.13.191.2554,094
221254.13.192.0/20254.13.192.1 to 254.13.207.254254.13.207.2554,094
222254.13.208.0/20254.13.208.1 to 254.13.223.254254.13.223.2554,094
223254.13.224.0/20254.13.224.1 to 254.13.239.254254.13.239.2554,094
224254.13.240.0/20254.13.240.1 to 254.13.255.254254.13.255.2554,094
225254.14.0.0/20254.14.0.1 to 254.14.15.254254.14.15.2554,094
226254.14.16.0/20254.14.16.1 to 254.14.31.254254.14.31.2554,094
227254.14.32.0/20254.14.32.1 to 254.14.47.254254.14.47.2554,094
228254.14.48.0/20254.14.48.1 to 254.14.63.254254.14.63.2554,094
229254.14.64.0/20254.14.64.1 to 254.14.79.254254.14.79.2554,094
230254.14.80.0/20254.14.80.1 to 254.14.95.254254.14.95.2554,094
231254.14.96.0/20254.14.96.1 to 254.14.111.254254.14.111.2554,094
232254.14.112.0/20254.14.112.1 to 254.14.127.254254.14.127.2554,094
233254.14.128.0/20254.14.128.1 to 254.14.143.254254.14.143.2554,094
234254.14.144.0/20254.14.144.1 to 254.14.159.254254.14.159.2554,094
235254.14.160.0/20254.14.160.1 to 254.14.175.254254.14.175.2554,094
236254.14.176.0/20254.14.176.1 to 254.14.191.254254.14.191.2554,094
237254.14.192.0/20254.14.192.1 to 254.14.207.254254.14.207.2554,094
238254.14.208.0/20254.14.208.1 to 254.14.223.254254.14.223.2554,094
239254.14.224.0/20254.14.224.1 to 254.14.239.254254.14.239.2554,094
240254.14.240.0/20254.14.240.1 to 254.14.255.254254.14.255.2554,094
241254.15.0.0/20254.15.0.1 to 254.15.15.254254.15.15.2554,094
242254.15.16.0/20254.15.16.1 to 254.15.31.254254.15.31.2554,094
243254.15.32.0/20254.15.32.1 to 254.15.47.254254.15.47.2554,094
244254.15.48.0/20254.15.48.1 to 254.15.63.254254.15.63.2554,094
245254.15.64.0/20254.15.64.1 to 254.15.79.254254.15.79.2554,094
246254.15.80.0/20254.15.80.1 to 254.15.95.254254.15.95.2554,094
247254.15.96.0/20254.15.96.1 to 254.15.111.254254.15.111.2554,094
248254.15.112.0/20254.15.112.1 to 254.15.127.254254.15.127.2554,094
249254.15.128.0/20254.15.128.1 to 254.15.143.254254.15.143.2554,094
250254.15.144.0/20254.15.144.1 to 254.15.159.254254.15.159.2554,094
251254.15.160.0/20254.15.160.1 to 254.15.175.254254.15.175.2554,094
252254.15.176.0/20254.15.176.1 to 254.15.191.254254.15.191.2554,094
253254.15.192.0/20254.15.192.1 to 254.15.207.254254.15.207.2554,094
254254.15.208.0/20254.15.208.1 to 254.15.223.254254.15.223.2554,094
255254.15.224.0/20254.15.224.1 to 254.15.239.254254.15.239.2554,094
256254.15.240.0/20254.15.240.1 to 254.15.255.254254.15.255.2554,094

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.