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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.

Network254.0.0.0/9
Usable hosts8,388,606
Subnet mask255.128.0.0
Addresses8,388,608
Network address
254.0.0.0
Broadcast address
254.127.255.255
First usable
254.0.0.1
Last usable
254.127.255.254
Usable hosts
8,388,606 (8,388,608 less the network and broadcast addresses)
Subnet mask
255.128.0.0
Wildcard mask
0.127.255.255 (Cisco ACLs, OSPF)
Prefix length
/9
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 4269801471
Reverse DNS zones
0.254.in-addr.arpa
1.254.in-addr.arpa
2.254.in-addr.arpa
3.254.in-addr.arpa
4.254.in-addr.arpa
5.254.in-addr.arpa
6.254.in-addr.arpa
7.254.in-addr.arpa
8.254.in-addr.arpa
9.254.in-addr.arpa
10.254.in-addr.arpa
11.254.in-addr.arpa
12.254.in-addr.arpa
13.254.in-addr.arpa
14.254.in-addr.arpa
15.254.in-addr.arpa
and 112 more
/9 is not on a 8-bit boundary, so it takes 128 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11111110.00000000.00000000.00000000254.0.0.0
Subnet mask11111111.10000000.00000000.00000000255.128.0.0
Network11111110.00000000.00000000.00000000254.0.0.0
Broadcast11111110.01111111.11111111.11111111254.127.255.255
Split into smaller subnets/21
/10 (2)/11 (4)/12 (8)/13 (16)/14 (32)/15 (64)/16 (128)/17 (256)/18 (512)/19 (1,024)/20 (2,048)/21 (4,096)

254.0.0.0/9 makes 4,096 subnets of /21; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1254.0.0.0/21254.0.0.1 to 254.0.7.254254.0.7.2552,046
2254.0.8.0/21254.0.8.1 to 254.0.15.254254.0.15.2552,046
3254.0.16.0/21254.0.16.1 to 254.0.23.254254.0.23.2552,046
4254.0.24.0/21254.0.24.1 to 254.0.31.254254.0.31.2552,046
5254.0.32.0/21254.0.32.1 to 254.0.39.254254.0.39.2552,046
6254.0.40.0/21254.0.40.1 to 254.0.47.254254.0.47.2552,046
7254.0.48.0/21254.0.48.1 to 254.0.55.254254.0.55.2552,046
8254.0.56.0/21254.0.56.1 to 254.0.63.254254.0.63.2552,046
9254.0.64.0/21254.0.64.1 to 254.0.71.254254.0.71.2552,046
10254.0.72.0/21254.0.72.1 to 254.0.79.254254.0.79.2552,046
11254.0.80.0/21254.0.80.1 to 254.0.87.254254.0.87.2552,046
12254.0.88.0/21254.0.88.1 to 254.0.95.254254.0.95.2552,046
13254.0.96.0/21254.0.96.1 to 254.0.103.254254.0.103.2552,046
14254.0.104.0/21254.0.104.1 to 254.0.111.254254.0.111.2552,046
15254.0.112.0/21254.0.112.1 to 254.0.119.254254.0.119.2552,046
16254.0.120.0/21254.0.120.1 to 254.0.127.254254.0.127.2552,046
17254.0.128.0/21254.0.128.1 to 254.0.135.254254.0.135.2552,046
18254.0.136.0/21254.0.136.1 to 254.0.143.254254.0.143.2552,046
19254.0.144.0/21254.0.144.1 to 254.0.151.254254.0.151.2552,046
20254.0.152.0/21254.0.152.1 to 254.0.159.254254.0.159.2552,046
21254.0.160.0/21254.0.160.1 to 254.0.167.254254.0.167.2552,046
22254.0.168.0/21254.0.168.1 to 254.0.175.254254.0.175.2552,046
23254.0.176.0/21254.0.176.1 to 254.0.183.254254.0.183.2552,046
24254.0.184.0/21254.0.184.1 to 254.0.191.254254.0.191.2552,046
25254.0.192.0/21254.0.192.1 to 254.0.199.254254.0.199.2552,046
26254.0.200.0/21254.0.200.1 to 254.0.207.254254.0.207.2552,046
27254.0.208.0/21254.0.208.1 to 254.0.215.254254.0.215.2552,046
28254.0.216.0/21254.0.216.1 to 254.0.223.254254.0.223.2552,046
29254.0.224.0/21254.0.224.1 to 254.0.231.254254.0.231.2552,046
30254.0.232.0/21254.0.232.1 to 254.0.239.254254.0.239.2552,046
31254.0.240.0/21254.0.240.1 to 254.0.247.254254.0.247.2552,046
32254.0.248.0/21254.0.248.1 to 254.0.255.254254.0.255.2552,046
33254.1.0.0/21254.1.0.1 to 254.1.7.254254.1.7.2552,046
34254.1.8.0/21254.1.8.1 to 254.1.15.254254.1.15.2552,046
35254.1.16.0/21254.1.16.1 to 254.1.23.254254.1.23.2552,046
36254.1.24.0/21254.1.24.1 to 254.1.31.254254.1.31.2552,046
37254.1.32.0/21254.1.32.1 to 254.1.39.254254.1.39.2552,046
38254.1.40.0/21254.1.40.1 to 254.1.47.254254.1.47.2552,046
39254.1.48.0/21254.1.48.1 to 254.1.55.254254.1.55.2552,046
40254.1.56.0/21254.1.56.1 to 254.1.63.254254.1.63.2552,046
41254.1.64.0/21254.1.64.1 to 254.1.71.254254.1.71.2552,046
42254.1.72.0/21254.1.72.1 to 254.1.79.254254.1.79.2552,046
43254.1.80.0/21254.1.80.1 to 254.1.87.254254.1.87.2552,046
44254.1.88.0/21254.1.88.1 to 254.1.95.254254.1.95.2552,046
45254.1.96.0/21254.1.96.1 to 254.1.103.254254.1.103.2552,046
46254.1.104.0/21254.1.104.1 to 254.1.111.254254.1.111.2552,046
47254.1.112.0/21254.1.112.1 to 254.1.119.254254.1.119.2552,046
48254.1.120.0/21254.1.120.1 to 254.1.127.254254.1.127.2552,046
49254.1.128.0/21254.1.128.1 to 254.1.135.254254.1.135.2552,046
50254.1.136.0/21254.1.136.1 to 254.1.143.254254.1.143.2552,046
51254.1.144.0/21254.1.144.1 to 254.1.151.254254.1.151.2552,046
52254.1.152.0/21254.1.152.1 to 254.1.159.254254.1.159.2552,046
53254.1.160.0/21254.1.160.1 to 254.1.167.254254.1.167.2552,046
54254.1.168.0/21254.1.168.1 to 254.1.175.254254.1.175.2552,046
55254.1.176.0/21254.1.176.1 to 254.1.183.254254.1.183.2552,046
56254.1.184.0/21254.1.184.1 to 254.1.191.254254.1.191.2552,046
57254.1.192.0/21254.1.192.1 to 254.1.199.254254.1.199.2552,046
58254.1.200.0/21254.1.200.1 to 254.1.207.254254.1.207.2552,046
59254.1.208.0/21254.1.208.1 to 254.1.215.254254.1.215.2552,046
60254.1.216.0/21254.1.216.1 to 254.1.223.254254.1.223.2552,046
61254.1.224.0/21254.1.224.1 to 254.1.231.254254.1.231.2552,046
62254.1.232.0/21254.1.232.1 to 254.1.239.254254.1.239.2552,046
63254.1.240.0/21254.1.240.1 to 254.1.247.254254.1.247.2552,046
64254.1.248.0/21254.1.248.1 to 254.1.255.254254.1.255.2552,046
65254.2.0.0/21254.2.0.1 to 254.2.7.254254.2.7.2552,046
66254.2.8.0/21254.2.8.1 to 254.2.15.254254.2.15.2552,046
67254.2.16.0/21254.2.16.1 to 254.2.23.254254.2.23.2552,046
68254.2.24.0/21254.2.24.1 to 254.2.31.254254.2.31.2552,046
69254.2.32.0/21254.2.32.1 to 254.2.39.254254.2.39.2552,046
70254.2.40.0/21254.2.40.1 to 254.2.47.254254.2.47.2552,046
71254.2.48.0/21254.2.48.1 to 254.2.55.254254.2.55.2552,046
72254.2.56.0/21254.2.56.1 to 254.2.63.254254.2.63.2552,046
73254.2.64.0/21254.2.64.1 to 254.2.71.254254.2.71.2552,046
74254.2.72.0/21254.2.72.1 to 254.2.79.254254.2.79.2552,046
75254.2.80.0/21254.2.80.1 to 254.2.87.254254.2.87.2552,046
76254.2.88.0/21254.2.88.1 to 254.2.95.254254.2.95.2552,046
77254.2.96.0/21254.2.96.1 to 254.2.103.254254.2.103.2552,046
78254.2.104.0/21254.2.104.1 to 254.2.111.254254.2.111.2552,046
79254.2.112.0/21254.2.112.1 to 254.2.119.254254.2.119.2552,046
80254.2.120.0/21254.2.120.1 to 254.2.127.254254.2.127.2552,046
81254.2.128.0/21254.2.128.1 to 254.2.135.254254.2.135.2552,046
82254.2.136.0/21254.2.136.1 to 254.2.143.254254.2.143.2552,046
83254.2.144.0/21254.2.144.1 to 254.2.151.254254.2.151.2552,046
84254.2.152.0/21254.2.152.1 to 254.2.159.254254.2.159.2552,046
85254.2.160.0/21254.2.160.1 to 254.2.167.254254.2.167.2552,046
86254.2.168.0/21254.2.168.1 to 254.2.175.254254.2.175.2552,046
87254.2.176.0/21254.2.176.1 to 254.2.183.254254.2.183.2552,046
88254.2.184.0/21254.2.184.1 to 254.2.191.254254.2.191.2552,046
89254.2.192.0/21254.2.192.1 to 254.2.199.254254.2.199.2552,046
90254.2.200.0/21254.2.200.1 to 254.2.207.254254.2.207.2552,046
91254.2.208.0/21254.2.208.1 to 254.2.215.254254.2.215.2552,046
92254.2.216.0/21254.2.216.1 to 254.2.223.254254.2.223.2552,046
93254.2.224.0/21254.2.224.1 to 254.2.231.254254.2.231.2552,046
94254.2.232.0/21254.2.232.1 to 254.2.239.254254.2.239.2552,046
95254.2.240.0/21254.2.240.1 to 254.2.247.254254.2.247.2552,046
96254.2.248.0/21254.2.248.1 to 254.2.255.254254.2.255.2552,046
97254.3.0.0/21254.3.0.1 to 254.3.7.254254.3.7.2552,046
98254.3.8.0/21254.3.8.1 to 254.3.15.254254.3.15.2552,046
99254.3.16.0/21254.3.16.1 to 254.3.23.254254.3.23.2552,046
100254.3.24.0/21254.3.24.1 to 254.3.31.254254.3.31.2552,046
101254.3.32.0/21254.3.32.1 to 254.3.39.254254.3.39.2552,046
102254.3.40.0/21254.3.40.1 to 254.3.47.254254.3.47.2552,046
103254.3.48.0/21254.3.48.1 to 254.3.55.254254.3.55.2552,046
104254.3.56.0/21254.3.56.1 to 254.3.63.254254.3.63.2552,046
105254.3.64.0/21254.3.64.1 to 254.3.71.254254.3.71.2552,046
106254.3.72.0/21254.3.72.1 to 254.3.79.254254.3.79.2552,046
107254.3.80.0/21254.3.80.1 to 254.3.87.254254.3.87.2552,046
108254.3.88.0/21254.3.88.1 to 254.3.95.254254.3.95.2552,046
109254.3.96.0/21254.3.96.1 to 254.3.103.254254.3.103.2552,046
110254.3.104.0/21254.3.104.1 to 254.3.111.254254.3.111.2552,046
111254.3.112.0/21254.3.112.1 to 254.3.119.254254.3.119.2552,046
112254.3.120.0/21254.3.120.1 to 254.3.127.254254.3.127.2552,046
113254.3.128.0/21254.3.128.1 to 254.3.135.254254.3.135.2552,046
114254.3.136.0/21254.3.136.1 to 254.3.143.254254.3.143.2552,046
115254.3.144.0/21254.3.144.1 to 254.3.151.254254.3.151.2552,046
116254.3.152.0/21254.3.152.1 to 254.3.159.254254.3.159.2552,046
117254.3.160.0/21254.3.160.1 to 254.3.167.254254.3.167.2552,046
118254.3.168.0/21254.3.168.1 to 254.3.175.254254.3.175.2552,046
119254.3.176.0/21254.3.176.1 to 254.3.183.254254.3.183.2552,046
120254.3.184.0/21254.3.184.1 to 254.3.191.254254.3.191.2552,046
121254.3.192.0/21254.3.192.1 to 254.3.199.254254.3.199.2552,046
122254.3.200.0/21254.3.200.1 to 254.3.207.254254.3.207.2552,046
123254.3.208.0/21254.3.208.1 to 254.3.215.254254.3.215.2552,046
124254.3.216.0/21254.3.216.1 to 254.3.223.254254.3.223.2552,046
125254.3.224.0/21254.3.224.1 to 254.3.231.254254.3.231.2552,046
126254.3.232.0/21254.3.232.1 to 254.3.239.254254.3.239.2552,046
127254.3.240.0/21254.3.240.1 to 254.3.247.254254.3.247.2552,046
128254.3.248.0/21254.3.248.1 to 254.3.255.254254.3.255.2552,046
129254.4.0.0/21254.4.0.1 to 254.4.7.254254.4.7.2552,046
130254.4.8.0/21254.4.8.1 to 254.4.15.254254.4.15.2552,046
131254.4.16.0/21254.4.16.1 to 254.4.23.254254.4.23.2552,046
132254.4.24.0/21254.4.24.1 to 254.4.31.254254.4.31.2552,046
133254.4.32.0/21254.4.32.1 to 254.4.39.254254.4.39.2552,046
134254.4.40.0/21254.4.40.1 to 254.4.47.254254.4.47.2552,046
135254.4.48.0/21254.4.48.1 to 254.4.55.254254.4.55.2552,046
136254.4.56.0/21254.4.56.1 to 254.4.63.254254.4.63.2552,046
137254.4.64.0/21254.4.64.1 to 254.4.71.254254.4.71.2552,046
138254.4.72.0/21254.4.72.1 to 254.4.79.254254.4.79.2552,046
139254.4.80.0/21254.4.80.1 to 254.4.87.254254.4.87.2552,046
140254.4.88.0/21254.4.88.1 to 254.4.95.254254.4.95.2552,046
141254.4.96.0/21254.4.96.1 to 254.4.103.254254.4.103.2552,046
142254.4.104.0/21254.4.104.1 to 254.4.111.254254.4.111.2552,046
143254.4.112.0/21254.4.112.1 to 254.4.119.254254.4.119.2552,046
144254.4.120.0/21254.4.120.1 to 254.4.127.254254.4.127.2552,046
145254.4.128.0/21254.4.128.1 to 254.4.135.254254.4.135.2552,046
146254.4.136.0/21254.4.136.1 to 254.4.143.254254.4.143.2552,046
147254.4.144.0/21254.4.144.1 to 254.4.151.254254.4.151.2552,046
148254.4.152.0/21254.4.152.1 to 254.4.159.254254.4.159.2552,046
149254.4.160.0/21254.4.160.1 to 254.4.167.254254.4.167.2552,046
150254.4.168.0/21254.4.168.1 to 254.4.175.254254.4.175.2552,046
151254.4.176.0/21254.4.176.1 to 254.4.183.254254.4.183.2552,046
152254.4.184.0/21254.4.184.1 to 254.4.191.254254.4.191.2552,046
153254.4.192.0/21254.4.192.1 to 254.4.199.254254.4.199.2552,046
154254.4.200.0/21254.4.200.1 to 254.4.207.254254.4.207.2552,046
155254.4.208.0/21254.4.208.1 to 254.4.215.254254.4.215.2552,046
156254.4.216.0/21254.4.216.1 to 254.4.223.254254.4.223.2552,046
157254.4.224.0/21254.4.224.1 to 254.4.231.254254.4.231.2552,046
158254.4.232.0/21254.4.232.1 to 254.4.239.254254.4.239.2552,046
159254.4.240.0/21254.4.240.1 to 254.4.247.254254.4.247.2552,046
160254.4.248.0/21254.4.248.1 to 254.4.255.254254.4.255.2552,046
161254.5.0.0/21254.5.0.1 to 254.5.7.254254.5.7.2552,046
162254.5.8.0/21254.5.8.1 to 254.5.15.254254.5.15.2552,046
163254.5.16.0/21254.5.16.1 to 254.5.23.254254.5.23.2552,046
164254.5.24.0/21254.5.24.1 to 254.5.31.254254.5.31.2552,046
165254.5.32.0/21254.5.32.1 to 254.5.39.254254.5.39.2552,046
166254.5.40.0/21254.5.40.1 to 254.5.47.254254.5.47.2552,046
167254.5.48.0/21254.5.48.1 to 254.5.55.254254.5.55.2552,046
168254.5.56.0/21254.5.56.1 to 254.5.63.254254.5.63.2552,046
169254.5.64.0/21254.5.64.1 to 254.5.71.254254.5.71.2552,046
170254.5.72.0/21254.5.72.1 to 254.5.79.254254.5.79.2552,046
171254.5.80.0/21254.5.80.1 to 254.5.87.254254.5.87.2552,046
172254.5.88.0/21254.5.88.1 to 254.5.95.254254.5.95.2552,046
173254.5.96.0/21254.5.96.1 to 254.5.103.254254.5.103.2552,046
174254.5.104.0/21254.5.104.1 to 254.5.111.254254.5.111.2552,046
175254.5.112.0/21254.5.112.1 to 254.5.119.254254.5.119.2552,046
176254.5.120.0/21254.5.120.1 to 254.5.127.254254.5.127.2552,046
177254.5.128.0/21254.5.128.1 to 254.5.135.254254.5.135.2552,046
178254.5.136.0/21254.5.136.1 to 254.5.143.254254.5.143.2552,046
179254.5.144.0/21254.5.144.1 to 254.5.151.254254.5.151.2552,046
180254.5.152.0/21254.5.152.1 to 254.5.159.254254.5.159.2552,046
181254.5.160.0/21254.5.160.1 to 254.5.167.254254.5.167.2552,046
182254.5.168.0/21254.5.168.1 to 254.5.175.254254.5.175.2552,046
183254.5.176.0/21254.5.176.1 to 254.5.183.254254.5.183.2552,046
184254.5.184.0/21254.5.184.1 to 254.5.191.254254.5.191.2552,046
185254.5.192.0/21254.5.192.1 to 254.5.199.254254.5.199.2552,046
186254.5.200.0/21254.5.200.1 to 254.5.207.254254.5.207.2552,046
187254.5.208.0/21254.5.208.1 to 254.5.215.254254.5.215.2552,046
188254.5.216.0/21254.5.216.1 to 254.5.223.254254.5.223.2552,046
189254.5.224.0/21254.5.224.1 to 254.5.231.254254.5.231.2552,046
190254.5.232.0/21254.5.232.1 to 254.5.239.254254.5.239.2552,046
191254.5.240.0/21254.5.240.1 to 254.5.247.254254.5.247.2552,046
192254.5.248.0/21254.5.248.1 to 254.5.255.254254.5.255.2552,046
193254.6.0.0/21254.6.0.1 to 254.6.7.254254.6.7.2552,046
194254.6.8.0/21254.6.8.1 to 254.6.15.254254.6.15.2552,046
195254.6.16.0/21254.6.16.1 to 254.6.23.254254.6.23.2552,046
196254.6.24.0/21254.6.24.1 to 254.6.31.254254.6.31.2552,046
197254.6.32.0/21254.6.32.1 to 254.6.39.254254.6.39.2552,046
198254.6.40.0/21254.6.40.1 to 254.6.47.254254.6.47.2552,046
199254.6.48.0/21254.6.48.1 to 254.6.55.254254.6.55.2552,046
200254.6.56.0/21254.6.56.1 to 254.6.63.254254.6.63.2552,046
201254.6.64.0/21254.6.64.1 to 254.6.71.254254.6.71.2552,046
202254.6.72.0/21254.6.72.1 to 254.6.79.254254.6.79.2552,046
203254.6.80.0/21254.6.80.1 to 254.6.87.254254.6.87.2552,046
204254.6.88.0/21254.6.88.1 to 254.6.95.254254.6.95.2552,046
205254.6.96.0/21254.6.96.1 to 254.6.103.254254.6.103.2552,046
206254.6.104.0/21254.6.104.1 to 254.6.111.254254.6.111.2552,046
207254.6.112.0/21254.6.112.1 to 254.6.119.254254.6.119.2552,046
208254.6.120.0/21254.6.120.1 to 254.6.127.254254.6.127.2552,046
209254.6.128.0/21254.6.128.1 to 254.6.135.254254.6.135.2552,046
210254.6.136.0/21254.6.136.1 to 254.6.143.254254.6.143.2552,046
211254.6.144.0/21254.6.144.1 to 254.6.151.254254.6.151.2552,046
212254.6.152.0/21254.6.152.1 to 254.6.159.254254.6.159.2552,046
213254.6.160.0/21254.6.160.1 to 254.6.167.254254.6.167.2552,046
214254.6.168.0/21254.6.168.1 to 254.6.175.254254.6.175.2552,046
215254.6.176.0/21254.6.176.1 to 254.6.183.254254.6.183.2552,046
216254.6.184.0/21254.6.184.1 to 254.6.191.254254.6.191.2552,046
217254.6.192.0/21254.6.192.1 to 254.6.199.254254.6.199.2552,046
218254.6.200.0/21254.6.200.1 to 254.6.207.254254.6.207.2552,046
219254.6.208.0/21254.6.208.1 to 254.6.215.254254.6.215.2552,046
220254.6.216.0/21254.6.216.1 to 254.6.223.254254.6.223.2552,046
221254.6.224.0/21254.6.224.1 to 254.6.231.254254.6.231.2552,046
222254.6.232.0/21254.6.232.1 to 254.6.239.254254.6.239.2552,046
223254.6.240.0/21254.6.240.1 to 254.6.247.254254.6.247.2552,046
224254.6.248.0/21254.6.248.1 to 254.6.255.254254.6.255.2552,046
225254.7.0.0/21254.7.0.1 to 254.7.7.254254.7.7.2552,046
226254.7.8.0/21254.7.8.1 to 254.7.15.254254.7.15.2552,046
227254.7.16.0/21254.7.16.1 to 254.7.23.254254.7.23.2552,046
228254.7.24.0/21254.7.24.1 to 254.7.31.254254.7.31.2552,046
229254.7.32.0/21254.7.32.1 to 254.7.39.254254.7.39.2552,046
230254.7.40.0/21254.7.40.1 to 254.7.47.254254.7.47.2552,046
231254.7.48.0/21254.7.48.1 to 254.7.55.254254.7.55.2552,046
232254.7.56.0/21254.7.56.1 to 254.7.63.254254.7.63.2552,046
233254.7.64.0/21254.7.64.1 to 254.7.71.254254.7.71.2552,046
234254.7.72.0/21254.7.72.1 to 254.7.79.254254.7.79.2552,046
235254.7.80.0/21254.7.80.1 to 254.7.87.254254.7.87.2552,046
236254.7.88.0/21254.7.88.1 to 254.7.95.254254.7.95.2552,046
237254.7.96.0/21254.7.96.1 to 254.7.103.254254.7.103.2552,046
238254.7.104.0/21254.7.104.1 to 254.7.111.254254.7.111.2552,046
239254.7.112.0/21254.7.112.1 to 254.7.119.254254.7.119.2552,046
240254.7.120.0/21254.7.120.1 to 254.7.127.254254.7.127.2552,046
241254.7.128.0/21254.7.128.1 to 254.7.135.254254.7.135.2552,046
242254.7.136.0/21254.7.136.1 to 254.7.143.254254.7.143.2552,046
243254.7.144.0/21254.7.144.1 to 254.7.151.254254.7.151.2552,046
244254.7.152.0/21254.7.152.1 to 254.7.159.254254.7.159.2552,046
245254.7.160.0/21254.7.160.1 to 254.7.167.254254.7.167.2552,046
246254.7.168.0/21254.7.168.1 to 254.7.175.254254.7.175.2552,046
247254.7.176.0/21254.7.176.1 to 254.7.183.254254.7.183.2552,046
248254.7.184.0/21254.7.184.1 to 254.7.191.254254.7.191.2552,046
249254.7.192.0/21254.7.192.1 to 254.7.199.254254.7.199.2552,046
250254.7.200.0/21254.7.200.1 to 254.7.207.254254.7.207.2552,046
251254.7.208.0/21254.7.208.1 to 254.7.215.254254.7.215.2552,046
252254.7.216.0/21254.7.216.1 to 254.7.223.254254.7.223.2552,046
253254.7.224.0/21254.7.224.1 to 254.7.231.254254.7.231.2552,046
254254.7.232.0/21254.7.232.1 to 254.7.239.254254.7.239.2552,046
255254.7.240.0/21254.7.240.1 to 254.7.247.254254.7.247.2552,046
256254.7.248.0/21254.7.248.1 to 254.7.255.254254.7.255.2552,046

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.