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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.

Network242.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
242.0.0.0
Broadcast address
242.255.255.255
First usable
242.0.0.1
Last usable
242.255.255.254
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 F2000000 · Integer 4060086272 to 4076863487
Reverse DNS zone
242.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11110010..00000000.00000000.00000000242.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network11110010..00000000.00000000.00000000242.0.0.0
Broadcast11110010..11111111.11111111.11111111242.255.255.255
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)

242.0.0.0/8 makes 4,096 subnets of /20; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1242.0.0.0/20242.0.0.1 to 242.0.15.254242.0.15.2554,094
2242.0.16.0/20242.0.16.1 to 242.0.31.254242.0.31.2554,094
3242.0.32.0/20242.0.32.1 to 242.0.47.254242.0.47.2554,094
4242.0.48.0/20242.0.48.1 to 242.0.63.254242.0.63.2554,094
5242.0.64.0/20242.0.64.1 to 242.0.79.254242.0.79.2554,094
6242.0.80.0/20242.0.80.1 to 242.0.95.254242.0.95.2554,094
7242.0.96.0/20242.0.96.1 to 242.0.111.254242.0.111.2554,094
8242.0.112.0/20242.0.112.1 to 242.0.127.254242.0.127.2554,094
9242.0.128.0/20242.0.128.1 to 242.0.143.254242.0.143.2554,094
10242.0.144.0/20242.0.144.1 to 242.0.159.254242.0.159.2554,094
11242.0.160.0/20242.0.160.1 to 242.0.175.254242.0.175.2554,094
12242.0.176.0/20242.0.176.1 to 242.0.191.254242.0.191.2554,094
13242.0.192.0/20242.0.192.1 to 242.0.207.254242.0.207.2554,094
14242.0.208.0/20242.0.208.1 to 242.0.223.254242.0.223.2554,094
15242.0.224.0/20242.0.224.1 to 242.0.239.254242.0.239.2554,094
16242.0.240.0/20242.0.240.1 to 242.0.255.254242.0.255.2554,094
17242.1.0.0/20242.1.0.1 to 242.1.15.254242.1.15.2554,094
18242.1.16.0/20242.1.16.1 to 242.1.31.254242.1.31.2554,094
19242.1.32.0/20242.1.32.1 to 242.1.47.254242.1.47.2554,094
20242.1.48.0/20242.1.48.1 to 242.1.63.254242.1.63.2554,094
21242.1.64.0/20242.1.64.1 to 242.1.79.254242.1.79.2554,094
22242.1.80.0/20242.1.80.1 to 242.1.95.254242.1.95.2554,094
23242.1.96.0/20242.1.96.1 to 242.1.111.254242.1.111.2554,094
24242.1.112.0/20242.1.112.1 to 242.1.127.254242.1.127.2554,094
25242.1.128.0/20242.1.128.1 to 242.1.143.254242.1.143.2554,094
26242.1.144.0/20242.1.144.1 to 242.1.159.254242.1.159.2554,094
27242.1.160.0/20242.1.160.1 to 242.1.175.254242.1.175.2554,094
28242.1.176.0/20242.1.176.1 to 242.1.191.254242.1.191.2554,094
29242.1.192.0/20242.1.192.1 to 242.1.207.254242.1.207.2554,094
30242.1.208.0/20242.1.208.1 to 242.1.223.254242.1.223.2554,094
31242.1.224.0/20242.1.224.1 to 242.1.239.254242.1.239.2554,094
32242.1.240.0/20242.1.240.1 to 242.1.255.254242.1.255.2554,094
33242.2.0.0/20242.2.0.1 to 242.2.15.254242.2.15.2554,094
34242.2.16.0/20242.2.16.1 to 242.2.31.254242.2.31.2554,094
35242.2.32.0/20242.2.32.1 to 242.2.47.254242.2.47.2554,094
36242.2.48.0/20242.2.48.1 to 242.2.63.254242.2.63.2554,094
37242.2.64.0/20242.2.64.1 to 242.2.79.254242.2.79.2554,094
38242.2.80.0/20242.2.80.1 to 242.2.95.254242.2.95.2554,094
39242.2.96.0/20242.2.96.1 to 242.2.111.254242.2.111.2554,094
40242.2.112.0/20242.2.112.1 to 242.2.127.254242.2.127.2554,094
41242.2.128.0/20242.2.128.1 to 242.2.143.254242.2.143.2554,094
42242.2.144.0/20242.2.144.1 to 242.2.159.254242.2.159.2554,094
43242.2.160.0/20242.2.160.1 to 242.2.175.254242.2.175.2554,094
44242.2.176.0/20242.2.176.1 to 242.2.191.254242.2.191.2554,094
45242.2.192.0/20242.2.192.1 to 242.2.207.254242.2.207.2554,094
46242.2.208.0/20242.2.208.1 to 242.2.223.254242.2.223.2554,094
47242.2.224.0/20242.2.224.1 to 242.2.239.254242.2.239.2554,094
48242.2.240.0/20242.2.240.1 to 242.2.255.254242.2.255.2554,094
49242.3.0.0/20242.3.0.1 to 242.3.15.254242.3.15.2554,094
50242.3.16.0/20242.3.16.1 to 242.3.31.254242.3.31.2554,094
51242.3.32.0/20242.3.32.1 to 242.3.47.254242.3.47.2554,094
52242.3.48.0/20242.3.48.1 to 242.3.63.254242.3.63.2554,094
53242.3.64.0/20242.3.64.1 to 242.3.79.254242.3.79.2554,094
54242.3.80.0/20242.3.80.1 to 242.3.95.254242.3.95.2554,094
55242.3.96.0/20242.3.96.1 to 242.3.111.254242.3.111.2554,094
56242.3.112.0/20242.3.112.1 to 242.3.127.254242.3.127.2554,094
57242.3.128.0/20242.3.128.1 to 242.3.143.254242.3.143.2554,094
58242.3.144.0/20242.3.144.1 to 242.3.159.254242.3.159.2554,094
59242.3.160.0/20242.3.160.1 to 242.3.175.254242.3.175.2554,094
60242.3.176.0/20242.3.176.1 to 242.3.191.254242.3.191.2554,094
61242.3.192.0/20242.3.192.1 to 242.3.207.254242.3.207.2554,094
62242.3.208.0/20242.3.208.1 to 242.3.223.254242.3.223.2554,094
63242.3.224.0/20242.3.224.1 to 242.3.239.254242.3.239.2554,094
64242.3.240.0/20242.3.240.1 to 242.3.255.254242.3.255.2554,094
65242.4.0.0/20242.4.0.1 to 242.4.15.254242.4.15.2554,094
66242.4.16.0/20242.4.16.1 to 242.4.31.254242.4.31.2554,094
67242.4.32.0/20242.4.32.1 to 242.4.47.254242.4.47.2554,094
68242.4.48.0/20242.4.48.1 to 242.4.63.254242.4.63.2554,094
69242.4.64.0/20242.4.64.1 to 242.4.79.254242.4.79.2554,094
70242.4.80.0/20242.4.80.1 to 242.4.95.254242.4.95.2554,094
71242.4.96.0/20242.4.96.1 to 242.4.111.254242.4.111.2554,094
72242.4.112.0/20242.4.112.1 to 242.4.127.254242.4.127.2554,094
73242.4.128.0/20242.4.128.1 to 242.4.143.254242.4.143.2554,094
74242.4.144.0/20242.4.144.1 to 242.4.159.254242.4.159.2554,094
75242.4.160.0/20242.4.160.1 to 242.4.175.254242.4.175.2554,094
76242.4.176.0/20242.4.176.1 to 242.4.191.254242.4.191.2554,094
77242.4.192.0/20242.4.192.1 to 242.4.207.254242.4.207.2554,094
78242.4.208.0/20242.4.208.1 to 242.4.223.254242.4.223.2554,094
79242.4.224.0/20242.4.224.1 to 242.4.239.254242.4.239.2554,094
80242.4.240.0/20242.4.240.1 to 242.4.255.254242.4.255.2554,094
81242.5.0.0/20242.5.0.1 to 242.5.15.254242.5.15.2554,094
82242.5.16.0/20242.5.16.1 to 242.5.31.254242.5.31.2554,094
83242.5.32.0/20242.5.32.1 to 242.5.47.254242.5.47.2554,094
84242.5.48.0/20242.5.48.1 to 242.5.63.254242.5.63.2554,094
85242.5.64.0/20242.5.64.1 to 242.5.79.254242.5.79.2554,094
86242.5.80.0/20242.5.80.1 to 242.5.95.254242.5.95.2554,094
87242.5.96.0/20242.5.96.1 to 242.5.111.254242.5.111.2554,094
88242.5.112.0/20242.5.112.1 to 242.5.127.254242.5.127.2554,094
89242.5.128.0/20242.5.128.1 to 242.5.143.254242.5.143.2554,094
90242.5.144.0/20242.5.144.1 to 242.5.159.254242.5.159.2554,094
91242.5.160.0/20242.5.160.1 to 242.5.175.254242.5.175.2554,094
92242.5.176.0/20242.5.176.1 to 242.5.191.254242.5.191.2554,094
93242.5.192.0/20242.5.192.1 to 242.5.207.254242.5.207.2554,094
94242.5.208.0/20242.5.208.1 to 242.5.223.254242.5.223.2554,094
95242.5.224.0/20242.5.224.1 to 242.5.239.254242.5.239.2554,094
96242.5.240.0/20242.5.240.1 to 242.5.255.254242.5.255.2554,094
97242.6.0.0/20242.6.0.1 to 242.6.15.254242.6.15.2554,094
98242.6.16.0/20242.6.16.1 to 242.6.31.254242.6.31.2554,094
99242.6.32.0/20242.6.32.1 to 242.6.47.254242.6.47.2554,094
100242.6.48.0/20242.6.48.1 to 242.6.63.254242.6.63.2554,094
101242.6.64.0/20242.6.64.1 to 242.6.79.254242.6.79.2554,094
102242.6.80.0/20242.6.80.1 to 242.6.95.254242.6.95.2554,094
103242.6.96.0/20242.6.96.1 to 242.6.111.254242.6.111.2554,094
104242.6.112.0/20242.6.112.1 to 242.6.127.254242.6.127.2554,094
105242.6.128.0/20242.6.128.1 to 242.6.143.254242.6.143.2554,094
106242.6.144.0/20242.6.144.1 to 242.6.159.254242.6.159.2554,094
107242.6.160.0/20242.6.160.1 to 242.6.175.254242.6.175.2554,094
108242.6.176.0/20242.6.176.1 to 242.6.191.254242.6.191.2554,094
109242.6.192.0/20242.6.192.1 to 242.6.207.254242.6.207.2554,094
110242.6.208.0/20242.6.208.1 to 242.6.223.254242.6.223.2554,094
111242.6.224.0/20242.6.224.1 to 242.6.239.254242.6.239.2554,094
112242.6.240.0/20242.6.240.1 to 242.6.255.254242.6.255.2554,094
113242.7.0.0/20242.7.0.1 to 242.7.15.254242.7.15.2554,094
114242.7.16.0/20242.7.16.1 to 242.7.31.254242.7.31.2554,094
115242.7.32.0/20242.7.32.1 to 242.7.47.254242.7.47.2554,094
116242.7.48.0/20242.7.48.1 to 242.7.63.254242.7.63.2554,094
117242.7.64.0/20242.7.64.1 to 242.7.79.254242.7.79.2554,094
118242.7.80.0/20242.7.80.1 to 242.7.95.254242.7.95.2554,094
119242.7.96.0/20242.7.96.1 to 242.7.111.254242.7.111.2554,094
120242.7.112.0/20242.7.112.1 to 242.7.127.254242.7.127.2554,094
121242.7.128.0/20242.7.128.1 to 242.7.143.254242.7.143.2554,094
122242.7.144.0/20242.7.144.1 to 242.7.159.254242.7.159.2554,094
123242.7.160.0/20242.7.160.1 to 242.7.175.254242.7.175.2554,094
124242.7.176.0/20242.7.176.1 to 242.7.191.254242.7.191.2554,094
125242.7.192.0/20242.7.192.1 to 242.7.207.254242.7.207.2554,094
126242.7.208.0/20242.7.208.1 to 242.7.223.254242.7.223.2554,094
127242.7.224.0/20242.7.224.1 to 242.7.239.254242.7.239.2554,094
128242.7.240.0/20242.7.240.1 to 242.7.255.254242.7.255.2554,094
129242.8.0.0/20242.8.0.1 to 242.8.15.254242.8.15.2554,094
130242.8.16.0/20242.8.16.1 to 242.8.31.254242.8.31.2554,094
131242.8.32.0/20242.8.32.1 to 242.8.47.254242.8.47.2554,094
132242.8.48.0/20242.8.48.1 to 242.8.63.254242.8.63.2554,094
133242.8.64.0/20242.8.64.1 to 242.8.79.254242.8.79.2554,094
134242.8.80.0/20242.8.80.1 to 242.8.95.254242.8.95.2554,094
135242.8.96.0/20242.8.96.1 to 242.8.111.254242.8.111.2554,094
136242.8.112.0/20242.8.112.1 to 242.8.127.254242.8.127.2554,094
137242.8.128.0/20242.8.128.1 to 242.8.143.254242.8.143.2554,094
138242.8.144.0/20242.8.144.1 to 242.8.159.254242.8.159.2554,094
139242.8.160.0/20242.8.160.1 to 242.8.175.254242.8.175.2554,094
140242.8.176.0/20242.8.176.1 to 242.8.191.254242.8.191.2554,094
141242.8.192.0/20242.8.192.1 to 242.8.207.254242.8.207.2554,094
142242.8.208.0/20242.8.208.1 to 242.8.223.254242.8.223.2554,094
143242.8.224.0/20242.8.224.1 to 242.8.239.254242.8.239.2554,094
144242.8.240.0/20242.8.240.1 to 242.8.255.254242.8.255.2554,094
145242.9.0.0/20242.9.0.1 to 242.9.15.254242.9.15.2554,094
146242.9.16.0/20242.9.16.1 to 242.9.31.254242.9.31.2554,094
147242.9.32.0/20242.9.32.1 to 242.9.47.254242.9.47.2554,094
148242.9.48.0/20242.9.48.1 to 242.9.63.254242.9.63.2554,094
149242.9.64.0/20242.9.64.1 to 242.9.79.254242.9.79.2554,094
150242.9.80.0/20242.9.80.1 to 242.9.95.254242.9.95.2554,094
151242.9.96.0/20242.9.96.1 to 242.9.111.254242.9.111.2554,094
152242.9.112.0/20242.9.112.1 to 242.9.127.254242.9.127.2554,094
153242.9.128.0/20242.9.128.1 to 242.9.143.254242.9.143.2554,094
154242.9.144.0/20242.9.144.1 to 242.9.159.254242.9.159.2554,094
155242.9.160.0/20242.9.160.1 to 242.9.175.254242.9.175.2554,094
156242.9.176.0/20242.9.176.1 to 242.9.191.254242.9.191.2554,094
157242.9.192.0/20242.9.192.1 to 242.9.207.254242.9.207.2554,094
158242.9.208.0/20242.9.208.1 to 242.9.223.254242.9.223.2554,094
159242.9.224.0/20242.9.224.1 to 242.9.239.254242.9.239.2554,094
160242.9.240.0/20242.9.240.1 to 242.9.255.254242.9.255.2554,094
161242.10.0.0/20242.10.0.1 to 242.10.15.254242.10.15.2554,094
162242.10.16.0/20242.10.16.1 to 242.10.31.254242.10.31.2554,094
163242.10.32.0/20242.10.32.1 to 242.10.47.254242.10.47.2554,094
164242.10.48.0/20242.10.48.1 to 242.10.63.254242.10.63.2554,094
165242.10.64.0/20242.10.64.1 to 242.10.79.254242.10.79.2554,094
166242.10.80.0/20242.10.80.1 to 242.10.95.254242.10.95.2554,094
167242.10.96.0/20242.10.96.1 to 242.10.111.254242.10.111.2554,094
168242.10.112.0/20242.10.112.1 to 242.10.127.254242.10.127.2554,094
169242.10.128.0/20242.10.128.1 to 242.10.143.254242.10.143.2554,094
170242.10.144.0/20242.10.144.1 to 242.10.159.254242.10.159.2554,094
171242.10.160.0/20242.10.160.1 to 242.10.175.254242.10.175.2554,094
172242.10.176.0/20242.10.176.1 to 242.10.191.254242.10.191.2554,094
173242.10.192.0/20242.10.192.1 to 242.10.207.254242.10.207.2554,094
174242.10.208.0/20242.10.208.1 to 242.10.223.254242.10.223.2554,094
175242.10.224.0/20242.10.224.1 to 242.10.239.254242.10.239.2554,094
176242.10.240.0/20242.10.240.1 to 242.10.255.254242.10.255.2554,094
177242.11.0.0/20242.11.0.1 to 242.11.15.254242.11.15.2554,094
178242.11.16.0/20242.11.16.1 to 242.11.31.254242.11.31.2554,094
179242.11.32.0/20242.11.32.1 to 242.11.47.254242.11.47.2554,094
180242.11.48.0/20242.11.48.1 to 242.11.63.254242.11.63.2554,094
181242.11.64.0/20242.11.64.1 to 242.11.79.254242.11.79.2554,094
182242.11.80.0/20242.11.80.1 to 242.11.95.254242.11.95.2554,094
183242.11.96.0/20242.11.96.1 to 242.11.111.254242.11.111.2554,094
184242.11.112.0/20242.11.112.1 to 242.11.127.254242.11.127.2554,094
185242.11.128.0/20242.11.128.1 to 242.11.143.254242.11.143.2554,094
186242.11.144.0/20242.11.144.1 to 242.11.159.254242.11.159.2554,094
187242.11.160.0/20242.11.160.1 to 242.11.175.254242.11.175.2554,094
188242.11.176.0/20242.11.176.1 to 242.11.191.254242.11.191.2554,094
189242.11.192.0/20242.11.192.1 to 242.11.207.254242.11.207.2554,094
190242.11.208.0/20242.11.208.1 to 242.11.223.254242.11.223.2554,094
191242.11.224.0/20242.11.224.1 to 242.11.239.254242.11.239.2554,094
192242.11.240.0/20242.11.240.1 to 242.11.255.254242.11.255.2554,094
193242.12.0.0/20242.12.0.1 to 242.12.15.254242.12.15.2554,094
194242.12.16.0/20242.12.16.1 to 242.12.31.254242.12.31.2554,094
195242.12.32.0/20242.12.32.1 to 242.12.47.254242.12.47.2554,094
196242.12.48.0/20242.12.48.1 to 242.12.63.254242.12.63.2554,094
197242.12.64.0/20242.12.64.1 to 242.12.79.254242.12.79.2554,094
198242.12.80.0/20242.12.80.1 to 242.12.95.254242.12.95.2554,094
199242.12.96.0/20242.12.96.1 to 242.12.111.254242.12.111.2554,094
200242.12.112.0/20242.12.112.1 to 242.12.127.254242.12.127.2554,094
201242.12.128.0/20242.12.128.1 to 242.12.143.254242.12.143.2554,094
202242.12.144.0/20242.12.144.1 to 242.12.159.254242.12.159.2554,094
203242.12.160.0/20242.12.160.1 to 242.12.175.254242.12.175.2554,094
204242.12.176.0/20242.12.176.1 to 242.12.191.254242.12.191.2554,094
205242.12.192.0/20242.12.192.1 to 242.12.207.254242.12.207.2554,094
206242.12.208.0/20242.12.208.1 to 242.12.223.254242.12.223.2554,094
207242.12.224.0/20242.12.224.1 to 242.12.239.254242.12.239.2554,094
208242.12.240.0/20242.12.240.1 to 242.12.255.254242.12.255.2554,094
209242.13.0.0/20242.13.0.1 to 242.13.15.254242.13.15.2554,094
210242.13.16.0/20242.13.16.1 to 242.13.31.254242.13.31.2554,094
211242.13.32.0/20242.13.32.1 to 242.13.47.254242.13.47.2554,094
212242.13.48.0/20242.13.48.1 to 242.13.63.254242.13.63.2554,094
213242.13.64.0/20242.13.64.1 to 242.13.79.254242.13.79.2554,094
214242.13.80.0/20242.13.80.1 to 242.13.95.254242.13.95.2554,094
215242.13.96.0/20242.13.96.1 to 242.13.111.254242.13.111.2554,094
216242.13.112.0/20242.13.112.1 to 242.13.127.254242.13.127.2554,094
217242.13.128.0/20242.13.128.1 to 242.13.143.254242.13.143.2554,094
218242.13.144.0/20242.13.144.1 to 242.13.159.254242.13.159.2554,094
219242.13.160.0/20242.13.160.1 to 242.13.175.254242.13.175.2554,094
220242.13.176.0/20242.13.176.1 to 242.13.191.254242.13.191.2554,094
221242.13.192.0/20242.13.192.1 to 242.13.207.254242.13.207.2554,094
222242.13.208.0/20242.13.208.1 to 242.13.223.254242.13.223.2554,094
223242.13.224.0/20242.13.224.1 to 242.13.239.254242.13.239.2554,094
224242.13.240.0/20242.13.240.1 to 242.13.255.254242.13.255.2554,094
225242.14.0.0/20242.14.0.1 to 242.14.15.254242.14.15.2554,094
226242.14.16.0/20242.14.16.1 to 242.14.31.254242.14.31.2554,094
227242.14.32.0/20242.14.32.1 to 242.14.47.254242.14.47.2554,094
228242.14.48.0/20242.14.48.1 to 242.14.63.254242.14.63.2554,094
229242.14.64.0/20242.14.64.1 to 242.14.79.254242.14.79.2554,094
230242.14.80.0/20242.14.80.1 to 242.14.95.254242.14.95.2554,094
231242.14.96.0/20242.14.96.1 to 242.14.111.254242.14.111.2554,094
232242.14.112.0/20242.14.112.1 to 242.14.127.254242.14.127.2554,094
233242.14.128.0/20242.14.128.1 to 242.14.143.254242.14.143.2554,094
234242.14.144.0/20242.14.144.1 to 242.14.159.254242.14.159.2554,094
235242.14.160.0/20242.14.160.1 to 242.14.175.254242.14.175.2554,094
236242.14.176.0/20242.14.176.1 to 242.14.191.254242.14.191.2554,094
237242.14.192.0/20242.14.192.1 to 242.14.207.254242.14.207.2554,094
238242.14.208.0/20242.14.208.1 to 242.14.223.254242.14.223.2554,094
239242.14.224.0/20242.14.224.1 to 242.14.239.254242.14.239.2554,094
240242.14.240.0/20242.14.240.1 to 242.14.255.254242.14.255.2554,094
241242.15.0.0/20242.15.0.1 to 242.15.15.254242.15.15.2554,094
242242.15.16.0/20242.15.16.1 to 242.15.31.254242.15.31.2554,094
243242.15.32.0/20242.15.32.1 to 242.15.47.254242.15.47.2554,094
244242.15.48.0/20242.15.48.1 to 242.15.63.254242.15.63.2554,094
245242.15.64.0/20242.15.64.1 to 242.15.79.254242.15.79.2554,094
246242.15.80.0/20242.15.80.1 to 242.15.95.254242.15.95.2554,094
247242.15.96.0/20242.15.96.1 to 242.15.111.254242.15.111.2554,094
248242.15.112.0/20242.15.112.1 to 242.15.127.254242.15.127.2554,094
249242.15.128.0/20242.15.128.1 to 242.15.143.254242.15.143.2554,094
250242.15.144.0/20242.15.144.1 to 242.15.159.254242.15.159.2554,094
251242.15.160.0/20242.15.160.1 to 242.15.175.254242.15.175.2554,094
252242.15.176.0/20242.15.176.1 to 242.15.191.254242.15.191.2554,094
253242.15.192.0/20242.15.192.1 to 242.15.207.254242.15.207.2554,094
254242.15.208.0/20242.15.208.1 to 242.15.223.254242.15.223.2554,094
255242.15.224.0/20242.15.224.1 to 242.15.239.254242.15.239.2554,094
256242.15.240.0/20242.15.240.1 to 242.15.255.254242.15.255.2554,094

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.