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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.

Network248.0.0.0/9
Usable hosts8,388,606
Subnet mask255.128.0.0
Addresses8,388,608
Network address
248.0.0.0
Broadcast address
248.127.255.255
First usable
248.0.0.1
Last usable
248.127.255.254
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 F8000000 · Integer 4160749568 to 4169138175
Reverse DNS zones
0.248.in-addr.arpa
1.248.in-addr.arpa
2.248.in-addr.arpa
3.248.in-addr.arpa
4.248.in-addr.arpa
5.248.in-addr.arpa
6.248.in-addr.arpa
7.248.in-addr.arpa
8.248.in-addr.arpa
9.248.in-addr.arpa
10.248.in-addr.arpa
11.248.in-addr.arpa
12.248.in-addr.arpa
13.248.in-addr.arpa
14.248.in-addr.arpa
15.248.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
Address11111000.00000000.00000000.00000000248.0.0.0
Subnet mask11111111.10000000.00000000.00000000255.128.0.0
Network11111000.00000000.00000000.00000000248.0.0.0
Broadcast11111000.01111111.11111111.11111111248.127.255.255
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)

248.0.0.0/9 makes 4,096 subnets of /21; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1248.0.0.0/21248.0.0.1 to 248.0.7.254248.0.7.2552,046
2248.0.8.0/21248.0.8.1 to 248.0.15.254248.0.15.2552,046
3248.0.16.0/21248.0.16.1 to 248.0.23.254248.0.23.2552,046
4248.0.24.0/21248.0.24.1 to 248.0.31.254248.0.31.2552,046
5248.0.32.0/21248.0.32.1 to 248.0.39.254248.0.39.2552,046
6248.0.40.0/21248.0.40.1 to 248.0.47.254248.0.47.2552,046
7248.0.48.0/21248.0.48.1 to 248.0.55.254248.0.55.2552,046
8248.0.56.0/21248.0.56.1 to 248.0.63.254248.0.63.2552,046
9248.0.64.0/21248.0.64.1 to 248.0.71.254248.0.71.2552,046
10248.0.72.0/21248.0.72.1 to 248.0.79.254248.0.79.2552,046
11248.0.80.0/21248.0.80.1 to 248.0.87.254248.0.87.2552,046
12248.0.88.0/21248.0.88.1 to 248.0.95.254248.0.95.2552,046
13248.0.96.0/21248.0.96.1 to 248.0.103.254248.0.103.2552,046
14248.0.104.0/21248.0.104.1 to 248.0.111.254248.0.111.2552,046
15248.0.112.0/21248.0.112.1 to 248.0.119.254248.0.119.2552,046
16248.0.120.0/21248.0.120.1 to 248.0.127.254248.0.127.2552,046
17248.0.128.0/21248.0.128.1 to 248.0.135.254248.0.135.2552,046
18248.0.136.0/21248.0.136.1 to 248.0.143.254248.0.143.2552,046
19248.0.144.0/21248.0.144.1 to 248.0.151.254248.0.151.2552,046
20248.0.152.0/21248.0.152.1 to 248.0.159.254248.0.159.2552,046
21248.0.160.0/21248.0.160.1 to 248.0.167.254248.0.167.2552,046
22248.0.168.0/21248.0.168.1 to 248.0.175.254248.0.175.2552,046
23248.0.176.0/21248.0.176.1 to 248.0.183.254248.0.183.2552,046
24248.0.184.0/21248.0.184.1 to 248.0.191.254248.0.191.2552,046
25248.0.192.0/21248.0.192.1 to 248.0.199.254248.0.199.2552,046
26248.0.200.0/21248.0.200.1 to 248.0.207.254248.0.207.2552,046
27248.0.208.0/21248.0.208.1 to 248.0.215.254248.0.215.2552,046
28248.0.216.0/21248.0.216.1 to 248.0.223.254248.0.223.2552,046
29248.0.224.0/21248.0.224.1 to 248.0.231.254248.0.231.2552,046
30248.0.232.0/21248.0.232.1 to 248.0.239.254248.0.239.2552,046
31248.0.240.0/21248.0.240.1 to 248.0.247.254248.0.247.2552,046
32248.0.248.0/21248.0.248.1 to 248.0.255.254248.0.255.2552,046
33248.1.0.0/21248.1.0.1 to 248.1.7.254248.1.7.2552,046
34248.1.8.0/21248.1.8.1 to 248.1.15.254248.1.15.2552,046
35248.1.16.0/21248.1.16.1 to 248.1.23.254248.1.23.2552,046
36248.1.24.0/21248.1.24.1 to 248.1.31.254248.1.31.2552,046
37248.1.32.0/21248.1.32.1 to 248.1.39.254248.1.39.2552,046
38248.1.40.0/21248.1.40.1 to 248.1.47.254248.1.47.2552,046
39248.1.48.0/21248.1.48.1 to 248.1.55.254248.1.55.2552,046
40248.1.56.0/21248.1.56.1 to 248.1.63.254248.1.63.2552,046
41248.1.64.0/21248.1.64.1 to 248.1.71.254248.1.71.2552,046
42248.1.72.0/21248.1.72.1 to 248.1.79.254248.1.79.2552,046
43248.1.80.0/21248.1.80.1 to 248.1.87.254248.1.87.2552,046
44248.1.88.0/21248.1.88.1 to 248.1.95.254248.1.95.2552,046
45248.1.96.0/21248.1.96.1 to 248.1.103.254248.1.103.2552,046
46248.1.104.0/21248.1.104.1 to 248.1.111.254248.1.111.2552,046
47248.1.112.0/21248.1.112.1 to 248.1.119.254248.1.119.2552,046
48248.1.120.0/21248.1.120.1 to 248.1.127.254248.1.127.2552,046
49248.1.128.0/21248.1.128.1 to 248.1.135.254248.1.135.2552,046
50248.1.136.0/21248.1.136.1 to 248.1.143.254248.1.143.2552,046
51248.1.144.0/21248.1.144.1 to 248.1.151.254248.1.151.2552,046
52248.1.152.0/21248.1.152.1 to 248.1.159.254248.1.159.2552,046
53248.1.160.0/21248.1.160.1 to 248.1.167.254248.1.167.2552,046
54248.1.168.0/21248.1.168.1 to 248.1.175.254248.1.175.2552,046
55248.1.176.0/21248.1.176.1 to 248.1.183.254248.1.183.2552,046
56248.1.184.0/21248.1.184.1 to 248.1.191.254248.1.191.2552,046
57248.1.192.0/21248.1.192.1 to 248.1.199.254248.1.199.2552,046
58248.1.200.0/21248.1.200.1 to 248.1.207.254248.1.207.2552,046
59248.1.208.0/21248.1.208.1 to 248.1.215.254248.1.215.2552,046
60248.1.216.0/21248.1.216.1 to 248.1.223.254248.1.223.2552,046
61248.1.224.0/21248.1.224.1 to 248.1.231.254248.1.231.2552,046
62248.1.232.0/21248.1.232.1 to 248.1.239.254248.1.239.2552,046
63248.1.240.0/21248.1.240.1 to 248.1.247.254248.1.247.2552,046
64248.1.248.0/21248.1.248.1 to 248.1.255.254248.1.255.2552,046
65248.2.0.0/21248.2.0.1 to 248.2.7.254248.2.7.2552,046
66248.2.8.0/21248.2.8.1 to 248.2.15.254248.2.15.2552,046
67248.2.16.0/21248.2.16.1 to 248.2.23.254248.2.23.2552,046
68248.2.24.0/21248.2.24.1 to 248.2.31.254248.2.31.2552,046
69248.2.32.0/21248.2.32.1 to 248.2.39.254248.2.39.2552,046
70248.2.40.0/21248.2.40.1 to 248.2.47.254248.2.47.2552,046
71248.2.48.0/21248.2.48.1 to 248.2.55.254248.2.55.2552,046
72248.2.56.0/21248.2.56.1 to 248.2.63.254248.2.63.2552,046
73248.2.64.0/21248.2.64.1 to 248.2.71.254248.2.71.2552,046
74248.2.72.0/21248.2.72.1 to 248.2.79.254248.2.79.2552,046
75248.2.80.0/21248.2.80.1 to 248.2.87.254248.2.87.2552,046
76248.2.88.0/21248.2.88.1 to 248.2.95.254248.2.95.2552,046
77248.2.96.0/21248.2.96.1 to 248.2.103.254248.2.103.2552,046
78248.2.104.0/21248.2.104.1 to 248.2.111.254248.2.111.2552,046
79248.2.112.0/21248.2.112.1 to 248.2.119.254248.2.119.2552,046
80248.2.120.0/21248.2.120.1 to 248.2.127.254248.2.127.2552,046
81248.2.128.0/21248.2.128.1 to 248.2.135.254248.2.135.2552,046
82248.2.136.0/21248.2.136.1 to 248.2.143.254248.2.143.2552,046
83248.2.144.0/21248.2.144.1 to 248.2.151.254248.2.151.2552,046
84248.2.152.0/21248.2.152.1 to 248.2.159.254248.2.159.2552,046
85248.2.160.0/21248.2.160.1 to 248.2.167.254248.2.167.2552,046
86248.2.168.0/21248.2.168.1 to 248.2.175.254248.2.175.2552,046
87248.2.176.0/21248.2.176.1 to 248.2.183.254248.2.183.2552,046
88248.2.184.0/21248.2.184.1 to 248.2.191.254248.2.191.2552,046
89248.2.192.0/21248.2.192.1 to 248.2.199.254248.2.199.2552,046
90248.2.200.0/21248.2.200.1 to 248.2.207.254248.2.207.2552,046
91248.2.208.0/21248.2.208.1 to 248.2.215.254248.2.215.2552,046
92248.2.216.0/21248.2.216.1 to 248.2.223.254248.2.223.2552,046
93248.2.224.0/21248.2.224.1 to 248.2.231.254248.2.231.2552,046
94248.2.232.0/21248.2.232.1 to 248.2.239.254248.2.239.2552,046
95248.2.240.0/21248.2.240.1 to 248.2.247.254248.2.247.2552,046
96248.2.248.0/21248.2.248.1 to 248.2.255.254248.2.255.2552,046
97248.3.0.0/21248.3.0.1 to 248.3.7.254248.3.7.2552,046
98248.3.8.0/21248.3.8.1 to 248.3.15.254248.3.15.2552,046
99248.3.16.0/21248.3.16.1 to 248.3.23.254248.3.23.2552,046
100248.3.24.0/21248.3.24.1 to 248.3.31.254248.3.31.2552,046
101248.3.32.0/21248.3.32.1 to 248.3.39.254248.3.39.2552,046
102248.3.40.0/21248.3.40.1 to 248.3.47.254248.3.47.2552,046
103248.3.48.0/21248.3.48.1 to 248.3.55.254248.3.55.2552,046
104248.3.56.0/21248.3.56.1 to 248.3.63.254248.3.63.2552,046
105248.3.64.0/21248.3.64.1 to 248.3.71.254248.3.71.2552,046
106248.3.72.0/21248.3.72.1 to 248.3.79.254248.3.79.2552,046
107248.3.80.0/21248.3.80.1 to 248.3.87.254248.3.87.2552,046
108248.3.88.0/21248.3.88.1 to 248.3.95.254248.3.95.2552,046
109248.3.96.0/21248.3.96.1 to 248.3.103.254248.3.103.2552,046
110248.3.104.0/21248.3.104.1 to 248.3.111.254248.3.111.2552,046
111248.3.112.0/21248.3.112.1 to 248.3.119.254248.3.119.2552,046
112248.3.120.0/21248.3.120.1 to 248.3.127.254248.3.127.2552,046
113248.3.128.0/21248.3.128.1 to 248.3.135.254248.3.135.2552,046
114248.3.136.0/21248.3.136.1 to 248.3.143.254248.3.143.2552,046
115248.3.144.0/21248.3.144.1 to 248.3.151.254248.3.151.2552,046
116248.3.152.0/21248.3.152.1 to 248.3.159.254248.3.159.2552,046
117248.3.160.0/21248.3.160.1 to 248.3.167.254248.3.167.2552,046
118248.3.168.0/21248.3.168.1 to 248.3.175.254248.3.175.2552,046
119248.3.176.0/21248.3.176.1 to 248.3.183.254248.3.183.2552,046
120248.3.184.0/21248.3.184.1 to 248.3.191.254248.3.191.2552,046
121248.3.192.0/21248.3.192.1 to 248.3.199.254248.3.199.2552,046
122248.3.200.0/21248.3.200.1 to 248.3.207.254248.3.207.2552,046
123248.3.208.0/21248.3.208.1 to 248.3.215.254248.3.215.2552,046
124248.3.216.0/21248.3.216.1 to 248.3.223.254248.3.223.2552,046
125248.3.224.0/21248.3.224.1 to 248.3.231.254248.3.231.2552,046
126248.3.232.0/21248.3.232.1 to 248.3.239.254248.3.239.2552,046
127248.3.240.0/21248.3.240.1 to 248.3.247.254248.3.247.2552,046
128248.3.248.0/21248.3.248.1 to 248.3.255.254248.3.255.2552,046
129248.4.0.0/21248.4.0.1 to 248.4.7.254248.4.7.2552,046
130248.4.8.0/21248.4.8.1 to 248.4.15.254248.4.15.2552,046
131248.4.16.0/21248.4.16.1 to 248.4.23.254248.4.23.2552,046
132248.4.24.0/21248.4.24.1 to 248.4.31.254248.4.31.2552,046
133248.4.32.0/21248.4.32.1 to 248.4.39.254248.4.39.2552,046
134248.4.40.0/21248.4.40.1 to 248.4.47.254248.4.47.2552,046
135248.4.48.0/21248.4.48.1 to 248.4.55.254248.4.55.2552,046
136248.4.56.0/21248.4.56.1 to 248.4.63.254248.4.63.2552,046
137248.4.64.0/21248.4.64.1 to 248.4.71.254248.4.71.2552,046
138248.4.72.0/21248.4.72.1 to 248.4.79.254248.4.79.2552,046
139248.4.80.0/21248.4.80.1 to 248.4.87.254248.4.87.2552,046
140248.4.88.0/21248.4.88.1 to 248.4.95.254248.4.95.2552,046
141248.4.96.0/21248.4.96.1 to 248.4.103.254248.4.103.2552,046
142248.4.104.0/21248.4.104.1 to 248.4.111.254248.4.111.2552,046
143248.4.112.0/21248.4.112.1 to 248.4.119.254248.4.119.2552,046
144248.4.120.0/21248.4.120.1 to 248.4.127.254248.4.127.2552,046
145248.4.128.0/21248.4.128.1 to 248.4.135.254248.4.135.2552,046
146248.4.136.0/21248.4.136.1 to 248.4.143.254248.4.143.2552,046
147248.4.144.0/21248.4.144.1 to 248.4.151.254248.4.151.2552,046
148248.4.152.0/21248.4.152.1 to 248.4.159.254248.4.159.2552,046
149248.4.160.0/21248.4.160.1 to 248.4.167.254248.4.167.2552,046
150248.4.168.0/21248.4.168.1 to 248.4.175.254248.4.175.2552,046
151248.4.176.0/21248.4.176.1 to 248.4.183.254248.4.183.2552,046
152248.4.184.0/21248.4.184.1 to 248.4.191.254248.4.191.2552,046
153248.4.192.0/21248.4.192.1 to 248.4.199.254248.4.199.2552,046
154248.4.200.0/21248.4.200.1 to 248.4.207.254248.4.207.2552,046
155248.4.208.0/21248.4.208.1 to 248.4.215.254248.4.215.2552,046
156248.4.216.0/21248.4.216.1 to 248.4.223.254248.4.223.2552,046
157248.4.224.0/21248.4.224.1 to 248.4.231.254248.4.231.2552,046
158248.4.232.0/21248.4.232.1 to 248.4.239.254248.4.239.2552,046
159248.4.240.0/21248.4.240.1 to 248.4.247.254248.4.247.2552,046
160248.4.248.0/21248.4.248.1 to 248.4.255.254248.4.255.2552,046
161248.5.0.0/21248.5.0.1 to 248.5.7.254248.5.7.2552,046
162248.5.8.0/21248.5.8.1 to 248.5.15.254248.5.15.2552,046
163248.5.16.0/21248.5.16.1 to 248.5.23.254248.5.23.2552,046
164248.5.24.0/21248.5.24.1 to 248.5.31.254248.5.31.2552,046
165248.5.32.0/21248.5.32.1 to 248.5.39.254248.5.39.2552,046
166248.5.40.0/21248.5.40.1 to 248.5.47.254248.5.47.2552,046
167248.5.48.0/21248.5.48.1 to 248.5.55.254248.5.55.2552,046
168248.5.56.0/21248.5.56.1 to 248.5.63.254248.5.63.2552,046
169248.5.64.0/21248.5.64.1 to 248.5.71.254248.5.71.2552,046
170248.5.72.0/21248.5.72.1 to 248.5.79.254248.5.79.2552,046
171248.5.80.0/21248.5.80.1 to 248.5.87.254248.5.87.2552,046
172248.5.88.0/21248.5.88.1 to 248.5.95.254248.5.95.2552,046
173248.5.96.0/21248.5.96.1 to 248.5.103.254248.5.103.2552,046
174248.5.104.0/21248.5.104.1 to 248.5.111.254248.5.111.2552,046
175248.5.112.0/21248.5.112.1 to 248.5.119.254248.5.119.2552,046
176248.5.120.0/21248.5.120.1 to 248.5.127.254248.5.127.2552,046
177248.5.128.0/21248.5.128.1 to 248.5.135.254248.5.135.2552,046
178248.5.136.0/21248.5.136.1 to 248.5.143.254248.5.143.2552,046
179248.5.144.0/21248.5.144.1 to 248.5.151.254248.5.151.2552,046
180248.5.152.0/21248.5.152.1 to 248.5.159.254248.5.159.2552,046
181248.5.160.0/21248.5.160.1 to 248.5.167.254248.5.167.2552,046
182248.5.168.0/21248.5.168.1 to 248.5.175.254248.5.175.2552,046
183248.5.176.0/21248.5.176.1 to 248.5.183.254248.5.183.2552,046
184248.5.184.0/21248.5.184.1 to 248.5.191.254248.5.191.2552,046
185248.5.192.0/21248.5.192.1 to 248.5.199.254248.5.199.2552,046
186248.5.200.0/21248.5.200.1 to 248.5.207.254248.5.207.2552,046
187248.5.208.0/21248.5.208.1 to 248.5.215.254248.5.215.2552,046
188248.5.216.0/21248.5.216.1 to 248.5.223.254248.5.223.2552,046
189248.5.224.0/21248.5.224.1 to 248.5.231.254248.5.231.2552,046
190248.5.232.0/21248.5.232.1 to 248.5.239.254248.5.239.2552,046
191248.5.240.0/21248.5.240.1 to 248.5.247.254248.5.247.2552,046
192248.5.248.0/21248.5.248.1 to 248.5.255.254248.5.255.2552,046
193248.6.0.0/21248.6.0.1 to 248.6.7.254248.6.7.2552,046
194248.6.8.0/21248.6.8.1 to 248.6.15.254248.6.15.2552,046
195248.6.16.0/21248.6.16.1 to 248.6.23.254248.6.23.2552,046
196248.6.24.0/21248.6.24.1 to 248.6.31.254248.6.31.2552,046
197248.6.32.0/21248.6.32.1 to 248.6.39.254248.6.39.2552,046
198248.6.40.0/21248.6.40.1 to 248.6.47.254248.6.47.2552,046
199248.6.48.0/21248.6.48.1 to 248.6.55.254248.6.55.2552,046
200248.6.56.0/21248.6.56.1 to 248.6.63.254248.6.63.2552,046
201248.6.64.0/21248.6.64.1 to 248.6.71.254248.6.71.2552,046
202248.6.72.0/21248.6.72.1 to 248.6.79.254248.6.79.2552,046
203248.6.80.0/21248.6.80.1 to 248.6.87.254248.6.87.2552,046
204248.6.88.0/21248.6.88.1 to 248.6.95.254248.6.95.2552,046
205248.6.96.0/21248.6.96.1 to 248.6.103.254248.6.103.2552,046
206248.6.104.0/21248.6.104.1 to 248.6.111.254248.6.111.2552,046
207248.6.112.0/21248.6.112.1 to 248.6.119.254248.6.119.2552,046
208248.6.120.0/21248.6.120.1 to 248.6.127.254248.6.127.2552,046
209248.6.128.0/21248.6.128.1 to 248.6.135.254248.6.135.2552,046
210248.6.136.0/21248.6.136.1 to 248.6.143.254248.6.143.2552,046
211248.6.144.0/21248.6.144.1 to 248.6.151.254248.6.151.2552,046
212248.6.152.0/21248.6.152.1 to 248.6.159.254248.6.159.2552,046
213248.6.160.0/21248.6.160.1 to 248.6.167.254248.6.167.2552,046
214248.6.168.0/21248.6.168.1 to 248.6.175.254248.6.175.2552,046
215248.6.176.0/21248.6.176.1 to 248.6.183.254248.6.183.2552,046
216248.6.184.0/21248.6.184.1 to 248.6.191.254248.6.191.2552,046
217248.6.192.0/21248.6.192.1 to 248.6.199.254248.6.199.2552,046
218248.6.200.0/21248.6.200.1 to 248.6.207.254248.6.207.2552,046
219248.6.208.0/21248.6.208.1 to 248.6.215.254248.6.215.2552,046
220248.6.216.0/21248.6.216.1 to 248.6.223.254248.6.223.2552,046
221248.6.224.0/21248.6.224.1 to 248.6.231.254248.6.231.2552,046
222248.6.232.0/21248.6.232.1 to 248.6.239.254248.6.239.2552,046
223248.6.240.0/21248.6.240.1 to 248.6.247.254248.6.247.2552,046
224248.6.248.0/21248.6.248.1 to 248.6.255.254248.6.255.2552,046
225248.7.0.0/21248.7.0.1 to 248.7.7.254248.7.7.2552,046
226248.7.8.0/21248.7.8.1 to 248.7.15.254248.7.15.2552,046
227248.7.16.0/21248.7.16.1 to 248.7.23.254248.7.23.2552,046
228248.7.24.0/21248.7.24.1 to 248.7.31.254248.7.31.2552,046
229248.7.32.0/21248.7.32.1 to 248.7.39.254248.7.39.2552,046
230248.7.40.0/21248.7.40.1 to 248.7.47.254248.7.47.2552,046
231248.7.48.0/21248.7.48.1 to 248.7.55.254248.7.55.2552,046
232248.7.56.0/21248.7.56.1 to 248.7.63.254248.7.63.2552,046
233248.7.64.0/21248.7.64.1 to 248.7.71.254248.7.71.2552,046
234248.7.72.0/21248.7.72.1 to 248.7.79.254248.7.79.2552,046
235248.7.80.0/21248.7.80.1 to 248.7.87.254248.7.87.2552,046
236248.7.88.0/21248.7.88.1 to 248.7.95.254248.7.95.2552,046
237248.7.96.0/21248.7.96.1 to 248.7.103.254248.7.103.2552,046
238248.7.104.0/21248.7.104.1 to 248.7.111.254248.7.111.2552,046
239248.7.112.0/21248.7.112.1 to 248.7.119.254248.7.119.2552,046
240248.7.120.0/21248.7.120.1 to 248.7.127.254248.7.127.2552,046
241248.7.128.0/21248.7.128.1 to 248.7.135.254248.7.135.2552,046
242248.7.136.0/21248.7.136.1 to 248.7.143.254248.7.143.2552,046
243248.7.144.0/21248.7.144.1 to 248.7.151.254248.7.151.2552,046
244248.7.152.0/21248.7.152.1 to 248.7.159.254248.7.159.2552,046
245248.7.160.0/21248.7.160.1 to 248.7.167.254248.7.167.2552,046
246248.7.168.0/21248.7.168.1 to 248.7.175.254248.7.175.2552,046
247248.7.176.0/21248.7.176.1 to 248.7.183.254248.7.183.2552,046
248248.7.184.0/21248.7.184.1 to 248.7.191.254248.7.191.2552,046
249248.7.192.0/21248.7.192.1 to 248.7.199.254248.7.199.2552,046
250248.7.200.0/21248.7.200.1 to 248.7.207.254248.7.207.2552,046
251248.7.208.0/21248.7.208.1 to 248.7.215.254248.7.215.2552,046
252248.7.216.0/21248.7.216.1 to 248.7.223.254248.7.223.2552,046
253248.7.224.0/21248.7.224.1 to 248.7.231.254248.7.231.2552,046
254248.7.232.0/21248.7.232.1 to 248.7.239.254248.7.239.2552,046
255248.7.240.0/21248.7.240.1 to 248.7.247.254248.7.247.2552,046
256248.7.248.0/21248.7.248.1 to 248.7.255.254248.7.255.2552,046

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.