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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.

Network233.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
233.0.0.0
Broadcast address
233.255.255.255
First usable
233.0.0.1
Last usable
233.255.255.254
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
Multicast 224.0.0.0/4
One-to-many traffic, such as IPTV and routing protocols
Old class
D (multicast)
As numbers
Hex E9000000 · Integer 3909091328 to 3925868543
Reverse DNS zone
233.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11101001..00000000.00000000.00000000233.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network11101001..00000000.00000000.00000000233.0.0.0
Broadcast11101001..11111111.11111111.11111111233.255.255.255
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)

233.0.0.0/8 makes 1,024 subnets of /18; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1233.0.0.0/18233.0.0.1 to 233.0.63.254233.0.63.25516,382
2233.0.64.0/18233.0.64.1 to 233.0.127.254233.0.127.25516,382
3233.0.128.0/18233.0.128.1 to 233.0.191.254233.0.191.25516,382
4233.0.192.0/18233.0.192.1 to 233.0.255.254233.0.255.25516,382
5233.1.0.0/18233.1.0.1 to 233.1.63.254233.1.63.25516,382
6233.1.64.0/18233.1.64.1 to 233.1.127.254233.1.127.25516,382
7233.1.128.0/18233.1.128.1 to 233.1.191.254233.1.191.25516,382
8233.1.192.0/18233.1.192.1 to 233.1.255.254233.1.255.25516,382
9233.2.0.0/18233.2.0.1 to 233.2.63.254233.2.63.25516,382
10233.2.64.0/18233.2.64.1 to 233.2.127.254233.2.127.25516,382
11233.2.128.0/18233.2.128.1 to 233.2.191.254233.2.191.25516,382
12233.2.192.0/18233.2.192.1 to 233.2.255.254233.2.255.25516,382
13233.3.0.0/18233.3.0.1 to 233.3.63.254233.3.63.25516,382
14233.3.64.0/18233.3.64.1 to 233.3.127.254233.3.127.25516,382
15233.3.128.0/18233.3.128.1 to 233.3.191.254233.3.191.25516,382
16233.3.192.0/18233.3.192.1 to 233.3.255.254233.3.255.25516,382
17233.4.0.0/18233.4.0.1 to 233.4.63.254233.4.63.25516,382
18233.4.64.0/18233.4.64.1 to 233.4.127.254233.4.127.25516,382
19233.4.128.0/18233.4.128.1 to 233.4.191.254233.4.191.25516,382
20233.4.192.0/18233.4.192.1 to 233.4.255.254233.4.255.25516,382
21233.5.0.0/18233.5.0.1 to 233.5.63.254233.5.63.25516,382
22233.5.64.0/18233.5.64.1 to 233.5.127.254233.5.127.25516,382
23233.5.128.0/18233.5.128.1 to 233.5.191.254233.5.191.25516,382
24233.5.192.0/18233.5.192.1 to 233.5.255.254233.5.255.25516,382
25233.6.0.0/18233.6.0.1 to 233.6.63.254233.6.63.25516,382
26233.6.64.0/18233.6.64.1 to 233.6.127.254233.6.127.25516,382
27233.6.128.0/18233.6.128.1 to 233.6.191.254233.6.191.25516,382
28233.6.192.0/18233.6.192.1 to 233.6.255.254233.6.255.25516,382
29233.7.0.0/18233.7.0.1 to 233.7.63.254233.7.63.25516,382
30233.7.64.0/18233.7.64.1 to 233.7.127.254233.7.127.25516,382
31233.7.128.0/18233.7.128.1 to 233.7.191.254233.7.191.25516,382
32233.7.192.0/18233.7.192.1 to 233.7.255.254233.7.255.25516,382
33233.8.0.0/18233.8.0.1 to 233.8.63.254233.8.63.25516,382
34233.8.64.0/18233.8.64.1 to 233.8.127.254233.8.127.25516,382
35233.8.128.0/18233.8.128.1 to 233.8.191.254233.8.191.25516,382
36233.8.192.0/18233.8.192.1 to 233.8.255.254233.8.255.25516,382
37233.9.0.0/18233.9.0.1 to 233.9.63.254233.9.63.25516,382
38233.9.64.0/18233.9.64.1 to 233.9.127.254233.9.127.25516,382
39233.9.128.0/18233.9.128.1 to 233.9.191.254233.9.191.25516,382
40233.9.192.0/18233.9.192.1 to 233.9.255.254233.9.255.25516,382
41233.10.0.0/18233.10.0.1 to 233.10.63.254233.10.63.25516,382
42233.10.64.0/18233.10.64.1 to 233.10.127.254233.10.127.25516,382
43233.10.128.0/18233.10.128.1 to 233.10.191.254233.10.191.25516,382
44233.10.192.0/18233.10.192.1 to 233.10.255.254233.10.255.25516,382
45233.11.0.0/18233.11.0.1 to 233.11.63.254233.11.63.25516,382
46233.11.64.0/18233.11.64.1 to 233.11.127.254233.11.127.25516,382
47233.11.128.0/18233.11.128.1 to 233.11.191.254233.11.191.25516,382
48233.11.192.0/18233.11.192.1 to 233.11.255.254233.11.255.25516,382
49233.12.0.0/18233.12.0.1 to 233.12.63.254233.12.63.25516,382
50233.12.64.0/18233.12.64.1 to 233.12.127.254233.12.127.25516,382
51233.12.128.0/18233.12.128.1 to 233.12.191.254233.12.191.25516,382
52233.12.192.0/18233.12.192.1 to 233.12.255.254233.12.255.25516,382
53233.13.0.0/18233.13.0.1 to 233.13.63.254233.13.63.25516,382
54233.13.64.0/18233.13.64.1 to 233.13.127.254233.13.127.25516,382
55233.13.128.0/18233.13.128.1 to 233.13.191.254233.13.191.25516,382
56233.13.192.0/18233.13.192.1 to 233.13.255.254233.13.255.25516,382
57233.14.0.0/18233.14.0.1 to 233.14.63.254233.14.63.25516,382
58233.14.64.0/18233.14.64.1 to 233.14.127.254233.14.127.25516,382
59233.14.128.0/18233.14.128.1 to 233.14.191.254233.14.191.25516,382
60233.14.192.0/18233.14.192.1 to 233.14.255.254233.14.255.25516,382
61233.15.0.0/18233.15.0.1 to 233.15.63.254233.15.63.25516,382
62233.15.64.0/18233.15.64.1 to 233.15.127.254233.15.127.25516,382
63233.15.128.0/18233.15.128.1 to 233.15.191.254233.15.191.25516,382
64233.15.192.0/18233.15.192.1 to 233.15.255.254233.15.255.25516,382
65233.16.0.0/18233.16.0.1 to 233.16.63.254233.16.63.25516,382
66233.16.64.0/18233.16.64.1 to 233.16.127.254233.16.127.25516,382
67233.16.128.0/18233.16.128.1 to 233.16.191.254233.16.191.25516,382
68233.16.192.0/18233.16.192.1 to 233.16.255.254233.16.255.25516,382
69233.17.0.0/18233.17.0.1 to 233.17.63.254233.17.63.25516,382
70233.17.64.0/18233.17.64.1 to 233.17.127.254233.17.127.25516,382
71233.17.128.0/18233.17.128.1 to 233.17.191.254233.17.191.25516,382
72233.17.192.0/18233.17.192.1 to 233.17.255.254233.17.255.25516,382
73233.18.0.0/18233.18.0.1 to 233.18.63.254233.18.63.25516,382
74233.18.64.0/18233.18.64.1 to 233.18.127.254233.18.127.25516,382
75233.18.128.0/18233.18.128.1 to 233.18.191.254233.18.191.25516,382
76233.18.192.0/18233.18.192.1 to 233.18.255.254233.18.255.25516,382
77233.19.0.0/18233.19.0.1 to 233.19.63.254233.19.63.25516,382
78233.19.64.0/18233.19.64.1 to 233.19.127.254233.19.127.25516,382
79233.19.128.0/18233.19.128.1 to 233.19.191.254233.19.191.25516,382
80233.19.192.0/18233.19.192.1 to 233.19.255.254233.19.255.25516,382
81233.20.0.0/18233.20.0.1 to 233.20.63.254233.20.63.25516,382
82233.20.64.0/18233.20.64.1 to 233.20.127.254233.20.127.25516,382
83233.20.128.0/18233.20.128.1 to 233.20.191.254233.20.191.25516,382
84233.20.192.0/18233.20.192.1 to 233.20.255.254233.20.255.25516,382
85233.21.0.0/18233.21.0.1 to 233.21.63.254233.21.63.25516,382
86233.21.64.0/18233.21.64.1 to 233.21.127.254233.21.127.25516,382
87233.21.128.0/18233.21.128.1 to 233.21.191.254233.21.191.25516,382
88233.21.192.0/18233.21.192.1 to 233.21.255.254233.21.255.25516,382
89233.22.0.0/18233.22.0.1 to 233.22.63.254233.22.63.25516,382
90233.22.64.0/18233.22.64.1 to 233.22.127.254233.22.127.25516,382
91233.22.128.0/18233.22.128.1 to 233.22.191.254233.22.191.25516,382
92233.22.192.0/18233.22.192.1 to 233.22.255.254233.22.255.25516,382
93233.23.0.0/18233.23.0.1 to 233.23.63.254233.23.63.25516,382
94233.23.64.0/18233.23.64.1 to 233.23.127.254233.23.127.25516,382
95233.23.128.0/18233.23.128.1 to 233.23.191.254233.23.191.25516,382
96233.23.192.0/18233.23.192.1 to 233.23.255.254233.23.255.25516,382
97233.24.0.0/18233.24.0.1 to 233.24.63.254233.24.63.25516,382
98233.24.64.0/18233.24.64.1 to 233.24.127.254233.24.127.25516,382
99233.24.128.0/18233.24.128.1 to 233.24.191.254233.24.191.25516,382
100233.24.192.0/18233.24.192.1 to 233.24.255.254233.24.255.25516,382
101233.25.0.0/18233.25.0.1 to 233.25.63.254233.25.63.25516,382
102233.25.64.0/18233.25.64.1 to 233.25.127.254233.25.127.25516,382
103233.25.128.0/18233.25.128.1 to 233.25.191.254233.25.191.25516,382
104233.25.192.0/18233.25.192.1 to 233.25.255.254233.25.255.25516,382
105233.26.0.0/18233.26.0.1 to 233.26.63.254233.26.63.25516,382
106233.26.64.0/18233.26.64.1 to 233.26.127.254233.26.127.25516,382
107233.26.128.0/18233.26.128.1 to 233.26.191.254233.26.191.25516,382
108233.26.192.0/18233.26.192.1 to 233.26.255.254233.26.255.25516,382
109233.27.0.0/18233.27.0.1 to 233.27.63.254233.27.63.25516,382
110233.27.64.0/18233.27.64.1 to 233.27.127.254233.27.127.25516,382
111233.27.128.0/18233.27.128.1 to 233.27.191.254233.27.191.25516,382
112233.27.192.0/18233.27.192.1 to 233.27.255.254233.27.255.25516,382
113233.28.0.0/18233.28.0.1 to 233.28.63.254233.28.63.25516,382
114233.28.64.0/18233.28.64.1 to 233.28.127.254233.28.127.25516,382
115233.28.128.0/18233.28.128.1 to 233.28.191.254233.28.191.25516,382
116233.28.192.0/18233.28.192.1 to 233.28.255.254233.28.255.25516,382
117233.29.0.0/18233.29.0.1 to 233.29.63.254233.29.63.25516,382
118233.29.64.0/18233.29.64.1 to 233.29.127.254233.29.127.25516,382
119233.29.128.0/18233.29.128.1 to 233.29.191.254233.29.191.25516,382
120233.29.192.0/18233.29.192.1 to 233.29.255.254233.29.255.25516,382
121233.30.0.0/18233.30.0.1 to 233.30.63.254233.30.63.25516,382
122233.30.64.0/18233.30.64.1 to 233.30.127.254233.30.127.25516,382
123233.30.128.0/18233.30.128.1 to 233.30.191.254233.30.191.25516,382
124233.30.192.0/18233.30.192.1 to 233.30.255.254233.30.255.25516,382
125233.31.0.0/18233.31.0.1 to 233.31.63.254233.31.63.25516,382
126233.31.64.0/18233.31.64.1 to 233.31.127.254233.31.127.25516,382
127233.31.128.0/18233.31.128.1 to 233.31.191.254233.31.191.25516,382
128233.31.192.0/18233.31.192.1 to 233.31.255.254233.31.255.25516,382
129233.32.0.0/18233.32.0.1 to 233.32.63.254233.32.63.25516,382
130233.32.64.0/18233.32.64.1 to 233.32.127.254233.32.127.25516,382
131233.32.128.0/18233.32.128.1 to 233.32.191.254233.32.191.25516,382
132233.32.192.0/18233.32.192.1 to 233.32.255.254233.32.255.25516,382
133233.33.0.0/18233.33.0.1 to 233.33.63.254233.33.63.25516,382
134233.33.64.0/18233.33.64.1 to 233.33.127.254233.33.127.25516,382
135233.33.128.0/18233.33.128.1 to 233.33.191.254233.33.191.25516,382
136233.33.192.0/18233.33.192.1 to 233.33.255.254233.33.255.25516,382
137233.34.0.0/18233.34.0.1 to 233.34.63.254233.34.63.25516,382
138233.34.64.0/18233.34.64.1 to 233.34.127.254233.34.127.25516,382
139233.34.128.0/18233.34.128.1 to 233.34.191.254233.34.191.25516,382
140233.34.192.0/18233.34.192.1 to 233.34.255.254233.34.255.25516,382
141233.35.0.0/18233.35.0.1 to 233.35.63.254233.35.63.25516,382
142233.35.64.0/18233.35.64.1 to 233.35.127.254233.35.127.25516,382
143233.35.128.0/18233.35.128.1 to 233.35.191.254233.35.191.25516,382
144233.35.192.0/18233.35.192.1 to 233.35.255.254233.35.255.25516,382
145233.36.0.0/18233.36.0.1 to 233.36.63.254233.36.63.25516,382
146233.36.64.0/18233.36.64.1 to 233.36.127.254233.36.127.25516,382
147233.36.128.0/18233.36.128.1 to 233.36.191.254233.36.191.25516,382
148233.36.192.0/18233.36.192.1 to 233.36.255.254233.36.255.25516,382
149233.37.0.0/18233.37.0.1 to 233.37.63.254233.37.63.25516,382
150233.37.64.0/18233.37.64.1 to 233.37.127.254233.37.127.25516,382
151233.37.128.0/18233.37.128.1 to 233.37.191.254233.37.191.25516,382
152233.37.192.0/18233.37.192.1 to 233.37.255.254233.37.255.25516,382
153233.38.0.0/18233.38.0.1 to 233.38.63.254233.38.63.25516,382
154233.38.64.0/18233.38.64.1 to 233.38.127.254233.38.127.25516,382
155233.38.128.0/18233.38.128.1 to 233.38.191.254233.38.191.25516,382
156233.38.192.0/18233.38.192.1 to 233.38.255.254233.38.255.25516,382
157233.39.0.0/18233.39.0.1 to 233.39.63.254233.39.63.25516,382
158233.39.64.0/18233.39.64.1 to 233.39.127.254233.39.127.25516,382
159233.39.128.0/18233.39.128.1 to 233.39.191.254233.39.191.25516,382
160233.39.192.0/18233.39.192.1 to 233.39.255.254233.39.255.25516,382
161233.40.0.0/18233.40.0.1 to 233.40.63.254233.40.63.25516,382
162233.40.64.0/18233.40.64.1 to 233.40.127.254233.40.127.25516,382
163233.40.128.0/18233.40.128.1 to 233.40.191.254233.40.191.25516,382
164233.40.192.0/18233.40.192.1 to 233.40.255.254233.40.255.25516,382
165233.41.0.0/18233.41.0.1 to 233.41.63.254233.41.63.25516,382
166233.41.64.0/18233.41.64.1 to 233.41.127.254233.41.127.25516,382
167233.41.128.0/18233.41.128.1 to 233.41.191.254233.41.191.25516,382
168233.41.192.0/18233.41.192.1 to 233.41.255.254233.41.255.25516,382
169233.42.0.0/18233.42.0.1 to 233.42.63.254233.42.63.25516,382
170233.42.64.0/18233.42.64.1 to 233.42.127.254233.42.127.25516,382
171233.42.128.0/18233.42.128.1 to 233.42.191.254233.42.191.25516,382
172233.42.192.0/18233.42.192.1 to 233.42.255.254233.42.255.25516,382
173233.43.0.0/18233.43.0.1 to 233.43.63.254233.43.63.25516,382
174233.43.64.0/18233.43.64.1 to 233.43.127.254233.43.127.25516,382
175233.43.128.0/18233.43.128.1 to 233.43.191.254233.43.191.25516,382
176233.43.192.0/18233.43.192.1 to 233.43.255.254233.43.255.25516,382
177233.44.0.0/18233.44.0.1 to 233.44.63.254233.44.63.25516,382
178233.44.64.0/18233.44.64.1 to 233.44.127.254233.44.127.25516,382
179233.44.128.0/18233.44.128.1 to 233.44.191.254233.44.191.25516,382
180233.44.192.0/18233.44.192.1 to 233.44.255.254233.44.255.25516,382
181233.45.0.0/18233.45.0.1 to 233.45.63.254233.45.63.25516,382
182233.45.64.0/18233.45.64.1 to 233.45.127.254233.45.127.25516,382
183233.45.128.0/18233.45.128.1 to 233.45.191.254233.45.191.25516,382
184233.45.192.0/18233.45.192.1 to 233.45.255.254233.45.255.25516,382
185233.46.0.0/18233.46.0.1 to 233.46.63.254233.46.63.25516,382
186233.46.64.0/18233.46.64.1 to 233.46.127.254233.46.127.25516,382
187233.46.128.0/18233.46.128.1 to 233.46.191.254233.46.191.25516,382
188233.46.192.0/18233.46.192.1 to 233.46.255.254233.46.255.25516,382
189233.47.0.0/18233.47.0.1 to 233.47.63.254233.47.63.25516,382
190233.47.64.0/18233.47.64.1 to 233.47.127.254233.47.127.25516,382
191233.47.128.0/18233.47.128.1 to 233.47.191.254233.47.191.25516,382
192233.47.192.0/18233.47.192.1 to 233.47.255.254233.47.255.25516,382
193233.48.0.0/18233.48.0.1 to 233.48.63.254233.48.63.25516,382
194233.48.64.0/18233.48.64.1 to 233.48.127.254233.48.127.25516,382
195233.48.128.0/18233.48.128.1 to 233.48.191.254233.48.191.25516,382
196233.48.192.0/18233.48.192.1 to 233.48.255.254233.48.255.25516,382
197233.49.0.0/18233.49.0.1 to 233.49.63.254233.49.63.25516,382
198233.49.64.0/18233.49.64.1 to 233.49.127.254233.49.127.25516,382
199233.49.128.0/18233.49.128.1 to 233.49.191.254233.49.191.25516,382
200233.49.192.0/18233.49.192.1 to 233.49.255.254233.49.255.25516,382
201233.50.0.0/18233.50.0.1 to 233.50.63.254233.50.63.25516,382
202233.50.64.0/18233.50.64.1 to 233.50.127.254233.50.127.25516,382
203233.50.128.0/18233.50.128.1 to 233.50.191.254233.50.191.25516,382
204233.50.192.0/18233.50.192.1 to 233.50.255.254233.50.255.25516,382
205233.51.0.0/18233.51.0.1 to 233.51.63.254233.51.63.25516,382
206233.51.64.0/18233.51.64.1 to 233.51.127.254233.51.127.25516,382
207233.51.128.0/18233.51.128.1 to 233.51.191.254233.51.191.25516,382
208233.51.192.0/18233.51.192.1 to 233.51.255.254233.51.255.25516,382
209233.52.0.0/18233.52.0.1 to 233.52.63.254233.52.63.25516,382
210233.52.64.0/18233.52.64.1 to 233.52.127.254233.52.127.25516,382
211233.52.128.0/18233.52.128.1 to 233.52.191.254233.52.191.25516,382
212233.52.192.0/18233.52.192.1 to 233.52.255.254233.52.255.25516,382
213233.53.0.0/18233.53.0.1 to 233.53.63.254233.53.63.25516,382
214233.53.64.0/18233.53.64.1 to 233.53.127.254233.53.127.25516,382
215233.53.128.0/18233.53.128.1 to 233.53.191.254233.53.191.25516,382
216233.53.192.0/18233.53.192.1 to 233.53.255.254233.53.255.25516,382
217233.54.0.0/18233.54.0.1 to 233.54.63.254233.54.63.25516,382
218233.54.64.0/18233.54.64.1 to 233.54.127.254233.54.127.25516,382
219233.54.128.0/18233.54.128.1 to 233.54.191.254233.54.191.25516,382
220233.54.192.0/18233.54.192.1 to 233.54.255.254233.54.255.25516,382
221233.55.0.0/18233.55.0.1 to 233.55.63.254233.55.63.25516,382
222233.55.64.0/18233.55.64.1 to 233.55.127.254233.55.127.25516,382
223233.55.128.0/18233.55.128.1 to 233.55.191.254233.55.191.25516,382
224233.55.192.0/18233.55.192.1 to 233.55.255.254233.55.255.25516,382
225233.56.0.0/18233.56.0.1 to 233.56.63.254233.56.63.25516,382
226233.56.64.0/18233.56.64.1 to 233.56.127.254233.56.127.25516,382
227233.56.128.0/18233.56.128.1 to 233.56.191.254233.56.191.25516,382
228233.56.192.0/18233.56.192.1 to 233.56.255.254233.56.255.25516,382
229233.57.0.0/18233.57.0.1 to 233.57.63.254233.57.63.25516,382
230233.57.64.0/18233.57.64.1 to 233.57.127.254233.57.127.25516,382
231233.57.128.0/18233.57.128.1 to 233.57.191.254233.57.191.25516,382
232233.57.192.0/18233.57.192.1 to 233.57.255.254233.57.255.25516,382
233233.58.0.0/18233.58.0.1 to 233.58.63.254233.58.63.25516,382
234233.58.64.0/18233.58.64.1 to 233.58.127.254233.58.127.25516,382
235233.58.128.0/18233.58.128.1 to 233.58.191.254233.58.191.25516,382
236233.58.192.0/18233.58.192.1 to 233.58.255.254233.58.255.25516,382
237233.59.0.0/18233.59.0.1 to 233.59.63.254233.59.63.25516,382
238233.59.64.0/18233.59.64.1 to 233.59.127.254233.59.127.25516,382
239233.59.128.0/18233.59.128.1 to 233.59.191.254233.59.191.25516,382
240233.59.192.0/18233.59.192.1 to 233.59.255.254233.59.255.25516,382
241233.60.0.0/18233.60.0.1 to 233.60.63.254233.60.63.25516,382
242233.60.64.0/18233.60.64.1 to 233.60.127.254233.60.127.25516,382
243233.60.128.0/18233.60.128.1 to 233.60.191.254233.60.191.25516,382
244233.60.192.0/18233.60.192.1 to 233.60.255.254233.60.255.25516,382
245233.61.0.0/18233.61.0.1 to 233.61.63.254233.61.63.25516,382
246233.61.64.0/18233.61.64.1 to 233.61.127.254233.61.127.25516,382
247233.61.128.0/18233.61.128.1 to 233.61.191.254233.61.191.25516,382
248233.61.192.0/18233.61.192.1 to 233.61.255.254233.61.255.25516,382
249233.62.0.0/18233.62.0.1 to 233.62.63.254233.62.63.25516,382
250233.62.64.0/18233.62.64.1 to 233.62.127.254233.62.127.25516,382
251233.62.128.0/18233.62.128.1 to 233.62.191.254233.62.191.25516,382
252233.62.192.0/18233.62.192.1 to 233.62.255.254233.62.255.25516,382
253233.63.0.0/18233.63.0.1 to 233.63.63.254233.63.63.25516,382
254233.63.64.0/18233.63.64.1 to 233.63.127.254233.63.127.25516,382
255233.63.128.0/18233.63.128.1 to 233.63.191.254233.63.191.25516,382
256233.63.192.0/18233.63.192.1 to 233.63.255.254233.63.255.25516,382

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.