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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/18
/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 1,024 subnets of /18; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1242.0.0.0/18242.0.0.1 to 242.0.63.254242.0.63.25516,382
2242.0.64.0/18242.0.64.1 to 242.0.127.254242.0.127.25516,382
3242.0.128.0/18242.0.128.1 to 242.0.191.254242.0.191.25516,382
4242.0.192.0/18242.0.192.1 to 242.0.255.254242.0.255.25516,382
5242.1.0.0/18242.1.0.1 to 242.1.63.254242.1.63.25516,382
6242.1.64.0/18242.1.64.1 to 242.1.127.254242.1.127.25516,382
7242.1.128.0/18242.1.128.1 to 242.1.191.254242.1.191.25516,382
8242.1.192.0/18242.1.192.1 to 242.1.255.254242.1.255.25516,382
9242.2.0.0/18242.2.0.1 to 242.2.63.254242.2.63.25516,382
10242.2.64.0/18242.2.64.1 to 242.2.127.254242.2.127.25516,382
11242.2.128.0/18242.2.128.1 to 242.2.191.254242.2.191.25516,382
12242.2.192.0/18242.2.192.1 to 242.2.255.254242.2.255.25516,382
13242.3.0.0/18242.3.0.1 to 242.3.63.254242.3.63.25516,382
14242.3.64.0/18242.3.64.1 to 242.3.127.254242.3.127.25516,382
15242.3.128.0/18242.3.128.1 to 242.3.191.254242.3.191.25516,382
16242.3.192.0/18242.3.192.1 to 242.3.255.254242.3.255.25516,382
17242.4.0.0/18242.4.0.1 to 242.4.63.254242.4.63.25516,382
18242.4.64.0/18242.4.64.1 to 242.4.127.254242.4.127.25516,382
19242.4.128.0/18242.4.128.1 to 242.4.191.254242.4.191.25516,382
20242.4.192.0/18242.4.192.1 to 242.4.255.254242.4.255.25516,382
21242.5.0.0/18242.5.0.1 to 242.5.63.254242.5.63.25516,382
22242.5.64.0/18242.5.64.1 to 242.5.127.254242.5.127.25516,382
23242.5.128.0/18242.5.128.1 to 242.5.191.254242.5.191.25516,382
24242.5.192.0/18242.5.192.1 to 242.5.255.254242.5.255.25516,382
25242.6.0.0/18242.6.0.1 to 242.6.63.254242.6.63.25516,382
26242.6.64.0/18242.6.64.1 to 242.6.127.254242.6.127.25516,382
27242.6.128.0/18242.6.128.1 to 242.6.191.254242.6.191.25516,382
28242.6.192.0/18242.6.192.1 to 242.6.255.254242.6.255.25516,382
29242.7.0.0/18242.7.0.1 to 242.7.63.254242.7.63.25516,382
30242.7.64.0/18242.7.64.1 to 242.7.127.254242.7.127.25516,382
31242.7.128.0/18242.7.128.1 to 242.7.191.254242.7.191.25516,382
32242.7.192.0/18242.7.192.1 to 242.7.255.254242.7.255.25516,382
33242.8.0.0/18242.8.0.1 to 242.8.63.254242.8.63.25516,382
34242.8.64.0/18242.8.64.1 to 242.8.127.254242.8.127.25516,382
35242.8.128.0/18242.8.128.1 to 242.8.191.254242.8.191.25516,382
36242.8.192.0/18242.8.192.1 to 242.8.255.254242.8.255.25516,382
37242.9.0.0/18242.9.0.1 to 242.9.63.254242.9.63.25516,382
38242.9.64.0/18242.9.64.1 to 242.9.127.254242.9.127.25516,382
39242.9.128.0/18242.9.128.1 to 242.9.191.254242.9.191.25516,382
40242.9.192.0/18242.9.192.1 to 242.9.255.254242.9.255.25516,382
41242.10.0.0/18242.10.0.1 to 242.10.63.254242.10.63.25516,382
42242.10.64.0/18242.10.64.1 to 242.10.127.254242.10.127.25516,382
43242.10.128.0/18242.10.128.1 to 242.10.191.254242.10.191.25516,382
44242.10.192.0/18242.10.192.1 to 242.10.255.254242.10.255.25516,382
45242.11.0.0/18242.11.0.1 to 242.11.63.254242.11.63.25516,382
46242.11.64.0/18242.11.64.1 to 242.11.127.254242.11.127.25516,382
47242.11.128.0/18242.11.128.1 to 242.11.191.254242.11.191.25516,382
48242.11.192.0/18242.11.192.1 to 242.11.255.254242.11.255.25516,382
49242.12.0.0/18242.12.0.1 to 242.12.63.254242.12.63.25516,382
50242.12.64.0/18242.12.64.1 to 242.12.127.254242.12.127.25516,382
51242.12.128.0/18242.12.128.1 to 242.12.191.254242.12.191.25516,382
52242.12.192.0/18242.12.192.1 to 242.12.255.254242.12.255.25516,382
53242.13.0.0/18242.13.0.1 to 242.13.63.254242.13.63.25516,382
54242.13.64.0/18242.13.64.1 to 242.13.127.254242.13.127.25516,382
55242.13.128.0/18242.13.128.1 to 242.13.191.254242.13.191.25516,382
56242.13.192.0/18242.13.192.1 to 242.13.255.254242.13.255.25516,382
57242.14.0.0/18242.14.0.1 to 242.14.63.254242.14.63.25516,382
58242.14.64.0/18242.14.64.1 to 242.14.127.254242.14.127.25516,382
59242.14.128.0/18242.14.128.1 to 242.14.191.254242.14.191.25516,382
60242.14.192.0/18242.14.192.1 to 242.14.255.254242.14.255.25516,382
61242.15.0.0/18242.15.0.1 to 242.15.63.254242.15.63.25516,382
62242.15.64.0/18242.15.64.1 to 242.15.127.254242.15.127.25516,382
63242.15.128.0/18242.15.128.1 to 242.15.191.254242.15.191.25516,382
64242.15.192.0/18242.15.192.1 to 242.15.255.254242.15.255.25516,382
65242.16.0.0/18242.16.0.1 to 242.16.63.254242.16.63.25516,382
66242.16.64.0/18242.16.64.1 to 242.16.127.254242.16.127.25516,382
67242.16.128.0/18242.16.128.1 to 242.16.191.254242.16.191.25516,382
68242.16.192.0/18242.16.192.1 to 242.16.255.254242.16.255.25516,382
69242.17.0.0/18242.17.0.1 to 242.17.63.254242.17.63.25516,382
70242.17.64.0/18242.17.64.1 to 242.17.127.254242.17.127.25516,382
71242.17.128.0/18242.17.128.1 to 242.17.191.254242.17.191.25516,382
72242.17.192.0/18242.17.192.1 to 242.17.255.254242.17.255.25516,382
73242.18.0.0/18242.18.0.1 to 242.18.63.254242.18.63.25516,382
74242.18.64.0/18242.18.64.1 to 242.18.127.254242.18.127.25516,382
75242.18.128.0/18242.18.128.1 to 242.18.191.254242.18.191.25516,382
76242.18.192.0/18242.18.192.1 to 242.18.255.254242.18.255.25516,382
77242.19.0.0/18242.19.0.1 to 242.19.63.254242.19.63.25516,382
78242.19.64.0/18242.19.64.1 to 242.19.127.254242.19.127.25516,382
79242.19.128.0/18242.19.128.1 to 242.19.191.254242.19.191.25516,382
80242.19.192.0/18242.19.192.1 to 242.19.255.254242.19.255.25516,382
81242.20.0.0/18242.20.0.1 to 242.20.63.254242.20.63.25516,382
82242.20.64.0/18242.20.64.1 to 242.20.127.254242.20.127.25516,382
83242.20.128.0/18242.20.128.1 to 242.20.191.254242.20.191.25516,382
84242.20.192.0/18242.20.192.1 to 242.20.255.254242.20.255.25516,382
85242.21.0.0/18242.21.0.1 to 242.21.63.254242.21.63.25516,382
86242.21.64.0/18242.21.64.1 to 242.21.127.254242.21.127.25516,382
87242.21.128.0/18242.21.128.1 to 242.21.191.254242.21.191.25516,382
88242.21.192.0/18242.21.192.1 to 242.21.255.254242.21.255.25516,382
89242.22.0.0/18242.22.0.1 to 242.22.63.254242.22.63.25516,382
90242.22.64.0/18242.22.64.1 to 242.22.127.254242.22.127.25516,382
91242.22.128.0/18242.22.128.1 to 242.22.191.254242.22.191.25516,382
92242.22.192.0/18242.22.192.1 to 242.22.255.254242.22.255.25516,382
93242.23.0.0/18242.23.0.1 to 242.23.63.254242.23.63.25516,382
94242.23.64.0/18242.23.64.1 to 242.23.127.254242.23.127.25516,382
95242.23.128.0/18242.23.128.1 to 242.23.191.254242.23.191.25516,382
96242.23.192.0/18242.23.192.1 to 242.23.255.254242.23.255.25516,382
97242.24.0.0/18242.24.0.1 to 242.24.63.254242.24.63.25516,382
98242.24.64.0/18242.24.64.1 to 242.24.127.254242.24.127.25516,382
99242.24.128.0/18242.24.128.1 to 242.24.191.254242.24.191.25516,382
100242.24.192.0/18242.24.192.1 to 242.24.255.254242.24.255.25516,382
101242.25.0.0/18242.25.0.1 to 242.25.63.254242.25.63.25516,382
102242.25.64.0/18242.25.64.1 to 242.25.127.254242.25.127.25516,382
103242.25.128.0/18242.25.128.1 to 242.25.191.254242.25.191.25516,382
104242.25.192.0/18242.25.192.1 to 242.25.255.254242.25.255.25516,382
105242.26.0.0/18242.26.0.1 to 242.26.63.254242.26.63.25516,382
106242.26.64.0/18242.26.64.1 to 242.26.127.254242.26.127.25516,382
107242.26.128.0/18242.26.128.1 to 242.26.191.254242.26.191.25516,382
108242.26.192.0/18242.26.192.1 to 242.26.255.254242.26.255.25516,382
109242.27.0.0/18242.27.0.1 to 242.27.63.254242.27.63.25516,382
110242.27.64.0/18242.27.64.1 to 242.27.127.254242.27.127.25516,382
111242.27.128.0/18242.27.128.1 to 242.27.191.254242.27.191.25516,382
112242.27.192.0/18242.27.192.1 to 242.27.255.254242.27.255.25516,382
113242.28.0.0/18242.28.0.1 to 242.28.63.254242.28.63.25516,382
114242.28.64.0/18242.28.64.1 to 242.28.127.254242.28.127.25516,382
115242.28.128.0/18242.28.128.1 to 242.28.191.254242.28.191.25516,382
116242.28.192.0/18242.28.192.1 to 242.28.255.254242.28.255.25516,382
117242.29.0.0/18242.29.0.1 to 242.29.63.254242.29.63.25516,382
118242.29.64.0/18242.29.64.1 to 242.29.127.254242.29.127.25516,382
119242.29.128.0/18242.29.128.1 to 242.29.191.254242.29.191.25516,382
120242.29.192.0/18242.29.192.1 to 242.29.255.254242.29.255.25516,382
121242.30.0.0/18242.30.0.1 to 242.30.63.254242.30.63.25516,382
122242.30.64.0/18242.30.64.1 to 242.30.127.254242.30.127.25516,382
123242.30.128.0/18242.30.128.1 to 242.30.191.254242.30.191.25516,382
124242.30.192.0/18242.30.192.1 to 242.30.255.254242.30.255.25516,382
125242.31.0.0/18242.31.0.1 to 242.31.63.254242.31.63.25516,382
126242.31.64.0/18242.31.64.1 to 242.31.127.254242.31.127.25516,382
127242.31.128.0/18242.31.128.1 to 242.31.191.254242.31.191.25516,382
128242.31.192.0/18242.31.192.1 to 242.31.255.254242.31.255.25516,382
129242.32.0.0/18242.32.0.1 to 242.32.63.254242.32.63.25516,382
130242.32.64.0/18242.32.64.1 to 242.32.127.254242.32.127.25516,382
131242.32.128.0/18242.32.128.1 to 242.32.191.254242.32.191.25516,382
132242.32.192.0/18242.32.192.1 to 242.32.255.254242.32.255.25516,382
133242.33.0.0/18242.33.0.1 to 242.33.63.254242.33.63.25516,382
134242.33.64.0/18242.33.64.1 to 242.33.127.254242.33.127.25516,382
135242.33.128.0/18242.33.128.1 to 242.33.191.254242.33.191.25516,382
136242.33.192.0/18242.33.192.1 to 242.33.255.254242.33.255.25516,382
137242.34.0.0/18242.34.0.1 to 242.34.63.254242.34.63.25516,382
138242.34.64.0/18242.34.64.1 to 242.34.127.254242.34.127.25516,382
139242.34.128.0/18242.34.128.1 to 242.34.191.254242.34.191.25516,382
140242.34.192.0/18242.34.192.1 to 242.34.255.254242.34.255.25516,382
141242.35.0.0/18242.35.0.1 to 242.35.63.254242.35.63.25516,382
142242.35.64.0/18242.35.64.1 to 242.35.127.254242.35.127.25516,382
143242.35.128.0/18242.35.128.1 to 242.35.191.254242.35.191.25516,382
144242.35.192.0/18242.35.192.1 to 242.35.255.254242.35.255.25516,382
145242.36.0.0/18242.36.0.1 to 242.36.63.254242.36.63.25516,382
146242.36.64.0/18242.36.64.1 to 242.36.127.254242.36.127.25516,382
147242.36.128.0/18242.36.128.1 to 242.36.191.254242.36.191.25516,382
148242.36.192.0/18242.36.192.1 to 242.36.255.254242.36.255.25516,382
149242.37.0.0/18242.37.0.1 to 242.37.63.254242.37.63.25516,382
150242.37.64.0/18242.37.64.1 to 242.37.127.254242.37.127.25516,382
151242.37.128.0/18242.37.128.1 to 242.37.191.254242.37.191.25516,382
152242.37.192.0/18242.37.192.1 to 242.37.255.254242.37.255.25516,382
153242.38.0.0/18242.38.0.1 to 242.38.63.254242.38.63.25516,382
154242.38.64.0/18242.38.64.1 to 242.38.127.254242.38.127.25516,382
155242.38.128.0/18242.38.128.1 to 242.38.191.254242.38.191.25516,382
156242.38.192.0/18242.38.192.1 to 242.38.255.254242.38.255.25516,382
157242.39.0.0/18242.39.0.1 to 242.39.63.254242.39.63.25516,382
158242.39.64.0/18242.39.64.1 to 242.39.127.254242.39.127.25516,382
159242.39.128.0/18242.39.128.1 to 242.39.191.254242.39.191.25516,382
160242.39.192.0/18242.39.192.1 to 242.39.255.254242.39.255.25516,382
161242.40.0.0/18242.40.0.1 to 242.40.63.254242.40.63.25516,382
162242.40.64.0/18242.40.64.1 to 242.40.127.254242.40.127.25516,382
163242.40.128.0/18242.40.128.1 to 242.40.191.254242.40.191.25516,382
164242.40.192.0/18242.40.192.1 to 242.40.255.254242.40.255.25516,382
165242.41.0.0/18242.41.0.1 to 242.41.63.254242.41.63.25516,382
166242.41.64.0/18242.41.64.1 to 242.41.127.254242.41.127.25516,382
167242.41.128.0/18242.41.128.1 to 242.41.191.254242.41.191.25516,382
168242.41.192.0/18242.41.192.1 to 242.41.255.254242.41.255.25516,382
169242.42.0.0/18242.42.0.1 to 242.42.63.254242.42.63.25516,382
170242.42.64.0/18242.42.64.1 to 242.42.127.254242.42.127.25516,382
171242.42.128.0/18242.42.128.1 to 242.42.191.254242.42.191.25516,382
172242.42.192.0/18242.42.192.1 to 242.42.255.254242.42.255.25516,382
173242.43.0.0/18242.43.0.1 to 242.43.63.254242.43.63.25516,382
174242.43.64.0/18242.43.64.1 to 242.43.127.254242.43.127.25516,382
175242.43.128.0/18242.43.128.1 to 242.43.191.254242.43.191.25516,382
176242.43.192.0/18242.43.192.1 to 242.43.255.254242.43.255.25516,382
177242.44.0.0/18242.44.0.1 to 242.44.63.254242.44.63.25516,382
178242.44.64.0/18242.44.64.1 to 242.44.127.254242.44.127.25516,382
179242.44.128.0/18242.44.128.1 to 242.44.191.254242.44.191.25516,382
180242.44.192.0/18242.44.192.1 to 242.44.255.254242.44.255.25516,382
181242.45.0.0/18242.45.0.1 to 242.45.63.254242.45.63.25516,382
182242.45.64.0/18242.45.64.1 to 242.45.127.254242.45.127.25516,382
183242.45.128.0/18242.45.128.1 to 242.45.191.254242.45.191.25516,382
184242.45.192.0/18242.45.192.1 to 242.45.255.254242.45.255.25516,382
185242.46.0.0/18242.46.0.1 to 242.46.63.254242.46.63.25516,382
186242.46.64.0/18242.46.64.1 to 242.46.127.254242.46.127.25516,382
187242.46.128.0/18242.46.128.1 to 242.46.191.254242.46.191.25516,382
188242.46.192.0/18242.46.192.1 to 242.46.255.254242.46.255.25516,382
189242.47.0.0/18242.47.0.1 to 242.47.63.254242.47.63.25516,382
190242.47.64.0/18242.47.64.1 to 242.47.127.254242.47.127.25516,382
191242.47.128.0/18242.47.128.1 to 242.47.191.254242.47.191.25516,382
192242.47.192.0/18242.47.192.1 to 242.47.255.254242.47.255.25516,382
193242.48.0.0/18242.48.0.1 to 242.48.63.254242.48.63.25516,382
194242.48.64.0/18242.48.64.1 to 242.48.127.254242.48.127.25516,382
195242.48.128.0/18242.48.128.1 to 242.48.191.254242.48.191.25516,382
196242.48.192.0/18242.48.192.1 to 242.48.255.254242.48.255.25516,382
197242.49.0.0/18242.49.0.1 to 242.49.63.254242.49.63.25516,382
198242.49.64.0/18242.49.64.1 to 242.49.127.254242.49.127.25516,382
199242.49.128.0/18242.49.128.1 to 242.49.191.254242.49.191.25516,382
200242.49.192.0/18242.49.192.1 to 242.49.255.254242.49.255.25516,382
201242.50.0.0/18242.50.0.1 to 242.50.63.254242.50.63.25516,382
202242.50.64.0/18242.50.64.1 to 242.50.127.254242.50.127.25516,382
203242.50.128.0/18242.50.128.1 to 242.50.191.254242.50.191.25516,382
204242.50.192.0/18242.50.192.1 to 242.50.255.254242.50.255.25516,382
205242.51.0.0/18242.51.0.1 to 242.51.63.254242.51.63.25516,382
206242.51.64.0/18242.51.64.1 to 242.51.127.254242.51.127.25516,382
207242.51.128.0/18242.51.128.1 to 242.51.191.254242.51.191.25516,382
208242.51.192.0/18242.51.192.1 to 242.51.255.254242.51.255.25516,382
209242.52.0.0/18242.52.0.1 to 242.52.63.254242.52.63.25516,382
210242.52.64.0/18242.52.64.1 to 242.52.127.254242.52.127.25516,382
211242.52.128.0/18242.52.128.1 to 242.52.191.254242.52.191.25516,382
212242.52.192.0/18242.52.192.1 to 242.52.255.254242.52.255.25516,382
213242.53.0.0/18242.53.0.1 to 242.53.63.254242.53.63.25516,382
214242.53.64.0/18242.53.64.1 to 242.53.127.254242.53.127.25516,382
215242.53.128.0/18242.53.128.1 to 242.53.191.254242.53.191.25516,382
216242.53.192.0/18242.53.192.1 to 242.53.255.254242.53.255.25516,382
217242.54.0.0/18242.54.0.1 to 242.54.63.254242.54.63.25516,382
218242.54.64.0/18242.54.64.1 to 242.54.127.254242.54.127.25516,382
219242.54.128.0/18242.54.128.1 to 242.54.191.254242.54.191.25516,382
220242.54.192.0/18242.54.192.1 to 242.54.255.254242.54.255.25516,382
221242.55.0.0/18242.55.0.1 to 242.55.63.254242.55.63.25516,382
222242.55.64.0/18242.55.64.1 to 242.55.127.254242.55.127.25516,382
223242.55.128.0/18242.55.128.1 to 242.55.191.254242.55.191.25516,382
224242.55.192.0/18242.55.192.1 to 242.55.255.254242.55.255.25516,382
225242.56.0.0/18242.56.0.1 to 242.56.63.254242.56.63.25516,382
226242.56.64.0/18242.56.64.1 to 242.56.127.254242.56.127.25516,382
227242.56.128.0/18242.56.128.1 to 242.56.191.254242.56.191.25516,382
228242.56.192.0/18242.56.192.1 to 242.56.255.254242.56.255.25516,382
229242.57.0.0/18242.57.0.1 to 242.57.63.254242.57.63.25516,382
230242.57.64.0/18242.57.64.1 to 242.57.127.254242.57.127.25516,382
231242.57.128.0/18242.57.128.1 to 242.57.191.254242.57.191.25516,382
232242.57.192.0/18242.57.192.1 to 242.57.255.254242.57.255.25516,382
233242.58.0.0/18242.58.0.1 to 242.58.63.254242.58.63.25516,382
234242.58.64.0/18242.58.64.1 to 242.58.127.254242.58.127.25516,382
235242.58.128.0/18242.58.128.1 to 242.58.191.254242.58.191.25516,382
236242.58.192.0/18242.58.192.1 to 242.58.255.254242.58.255.25516,382
237242.59.0.0/18242.59.0.1 to 242.59.63.254242.59.63.25516,382
238242.59.64.0/18242.59.64.1 to 242.59.127.254242.59.127.25516,382
239242.59.128.0/18242.59.128.1 to 242.59.191.254242.59.191.25516,382
240242.59.192.0/18242.59.192.1 to 242.59.255.254242.59.255.25516,382
241242.60.0.0/18242.60.0.1 to 242.60.63.254242.60.63.25516,382
242242.60.64.0/18242.60.64.1 to 242.60.127.254242.60.127.25516,382
243242.60.128.0/18242.60.128.1 to 242.60.191.254242.60.191.25516,382
244242.60.192.0/18242.60.192.1 to 242.60.255.254242.60.255.25516,382
245242.61.0.0/18242.61.0.1 to 242.61.63.254242.61.63.25516,382
246242.61.64.0/18242.61.64.1 to 242.61.127.254242.61.127.25516,382
247242.61.128.0/18242.61.128.1 to 242.61.191.254242.61.191.25516,382
248242.61.192.0/18242.61.192.1 to 242.61.255.254242.61.255.25516,382
249242.62.0.0/18242.62.0.1 to 242.62.63.254242.62.63.25516,382
250242.62.64.0/18242.62.64.1 to 242.62.127.254242.62.127.25516,382
251242.62.128.0/18242.62.128.1 to 242.62.191.254242.62.191.25516,382
252242.62.192.0/18242.62.192.1 to 242.62.255.254242.62.255.25516,382
253242.63.0.0/18242.63.0.1 to 242.63.63.254242.63.63.25516,382
254242.63.64.0/18242.63.64.1 to 242.63.127.254242.63.127.25516,382
255242.63.128.0/18242.63.128.1 to 242.63.191.254242.63.191.25516,382
256242.63.192.0/18242.63.192.1 to 242.63.255.254242.63.255.25516,382

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.