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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.

Network233.0.0.0/10
Usable hosts4,194,302
Subnet mask255.192.0.0
Addresses4,194,304
Network address
233.0.0.0
Broadcast address
233.63.255.255
First usable
233.0.0.1
Last usable
233.63.255.254
Usable hosts
4,194,302 (4,194,304 less the network and broadcast addresses)
Subnet mask
255.192.0.0
Wildcard mask
0.63.255.255 (Cisco ACLs, OSPF)
Prefix length
/10
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 3913285631
Reverse DNS zones
0.233.in-addr.arpa
1.233.in-addr.arpa
2.233.in-addr.arpa
3.233.in-addr.arpa
4.233.in-addr.arpa
5.233.in-addr.arpa
6.233.in-addr.arpa
7.233.in-addr.arpa
8.233.in-addr.arpa
9.233.in-addr.arpa
10.233.in-addr.arpa
11.233.in-addr.arpa
12.233.in-addr.arpa
13.233.in-addr.arpa
14.233.in-addr.arpa
15.233.in-addr.arpa
and 48 more
/10 is not on a 8-bit boundary, so it takes 64 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11101001.00000000.00000000.00000000233.0.0.0
Subnet mask11111111.11000000.00000000.00000000255.192.0.0
Network11101001.00000000.00000000.00000000233.0.0.0
Broadcast11101001.00111111.11111111.11111111233.63.255.255
Split into smaller subnets/20
/11 (2)/12 (4)/13 (8)/14 (16)/15 (32)/16 (64)/17 (128)/18 (256)/19 (512)/20 (1,024)/21 (2,048)/22 (4,096)

233.0.0.0/10 makes 1,024 subnets of /20; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1233.0.0.0/20233.0.0.1 to 233.0.15.254233.0.15.2554,094
2233.0.16.0/20233.0.16.1 to 233.0.31.254233.0.31.2554,094
3233.0.32.0/20233.0.32.1 to 233.0.47.254233.0.47.2554,094
4233.0.48.0/20233.0.48.1 to 233.0.63.254233.0.63.2554,094
5233.0.64.0/20233.0.64.1 to 233.0.79.254233.0.79.2554,094
6233.0.80.0/20233.0.80.1 to 233.0.95.254233.0.95.2554,094
7233.0.96.0/20233.0.96.1 to 233.0.111.254233.0.111.2554,094
8233.0.112.0/20233.0.112.1 to 233.0.127.254233.0.127.2554,094
9233.0.128.0/20233.0.128.1 to 233.0.143.254233.0.143.2554,094
10233.0.144.0/20233.0.144.1 to 233.0.159.254233.0.159.2554,094
11233.0.160.0/20233.0.160.1 to 233.0.175.254233.0.175.2554,094
12233.0.176.0/20233.0.176.1 to 233.0.191.254233.0.191.2554,094
13233.0.192.0/20233.0.192.1 to 233.0.207.254233.0.207.2554,094
14233.0.208.0/20233.0.208.1 to 233.0.223.254233.0.223.2554,094
15233.0.224.0/20233.0.224.1 to 233.0.239.254233.0.239.2554,094
16233.0.240.0/20233.0.240.1 to 233.0.255.254233.0.255.2554,094
17233.1.0.0/20233.1.0.1 to 233.1.15.254233.1.15.2554,094
18233.1.16.0/20233.1.16.1 to 233.1.31.254233.1.31.2554,094
19233.1.32.0/20233.1.32.1 to 233.1.47.254233.1.47.2554,094
20233.1.48.0/20233.1.48.1 to 233.1.63.254233.1.63.2554,094
21233.1.64.0/20233.1.64.1 to 233.1.79.254233.1.79.2554,094
22233.1.80.0/20233.1.80.1 to 233.1.95.254233.1.95.2554,094
23233.1.96.0/20233.1.96.1 to 233.1.111.254233.1.111.2554,094
24233.1.112.0/20233.1.112.1 to 233.1.127.254233.1.127.2554,094
25233.1.128.0/20233.1.128.1 to 233.1.143.254233.1.143.2554,094
26233.1.144.0/20233.1.144.1 to 233.1.159.254233.1.159.2554,094
27233.1.160.0/20233.1.160.1 to 233.1.175.254233.1.175.2554,094
28233.1.176.0/20233.1.176.1 to 233.1.191.254233.1.191.2554,094
29233.1.192.0/20233.1.192.1 to 233.1.207.254233.1.207.2554,094
30233.1.208.0/20233.1.208.1 to 233.1.223.254233.1.223.2554,094
31233.1.224.0/20233.1.224.1 to 233.1.239.254233.1.239.2554,094
32233.1.240.0/20233.1.240.1 to 233.1.255.254233.1.255.2554,094
33233.2.0.0/20233.2.0.1 to 233.2.15.254233.2.15.2554,094
34233.2.16.0/20233.2.16.1 to 233.2.31.254233.2.31.2554,094
35233.2.32.0/20233.2.32.1 to 233.2.47.254233.2.47.2554,094
36233.2.48.0/20233.2.48.1 to 233.2.63.254233.2.63.2554,094
37233.2.64.0/20233.2.64.1 to 233.2.79.254233.2.79.2554,094
38233.2.80.0/20233.2.80.1 to 233.2.95.254233.2.95.2554,094
39233.2.96.0/20233.2.96.1 to 233.2.111.254233.2.111.2554,094
40233.2.112.0/20233.2.112.1 to 233.2.127.254233.2.127.2554,094
41233.2.128.0/20233.2.128.1 to 233.2.143.254233.2.143.2554,094
42233.2.144.0/20233.2.144.1 to 233.2.159.254233.2.159.2554,094
43233.2.160.0/20233.2.160.1 to 233.2.175.254233.2.175.2554,094
44233.2.176.0/20233.2.176.1 to 233.2.191.254233.2.191.2554,094
45233.2.192.0/20233.2.192.1 to 233.2.207.254233.2.207.2554,094
46233.2.208.0/20233.2.208.1 to 233.2.223.254233.2.223.2554,094
47233.2.224.0/20233.2.224.1 to 233.2.239.254233.2.239.2554,094
48233.2.240.0/20233.2.240.1 to 233.2.255.254233.2.255.2554,094
49233.3.0.0/20233.3.0.1 to 233.3.15.254233.3.15.2554,094
50233.3.16.0/20233.3.16.1 to 233.3.31.254233.3.31.2554,094
51233.3.32.0/20233.3.32.1 to 233.3.47.254233.3.47.2554,094
52233.3.48.0/20233.3.48.1 to 233.3.63.254233.3.63.2554,094
53233.3.64.0/20233.3.64.1 to 233.3.79.254233.3.79.2554,094
54233.3.80.0/20233.3.80.1 to 233.3.95.254233.3.95.2554,094
55233.3.96.0/20233.3.96.1 to 233.3.111.254233.3.111.2554,094
56233.3.112.0/20233.3.112.1 to 233.3.127.254233.3.127.2554,094
57233.3.128.0/20233.3.128.1 to 233.3.143.254233.3.143.2554,094
58233.3.144.0/20233.3.144.1 to 233.3.159.254233.3.159.2554,094
59233.3.160.0/20233.3.160.1 to 233.3.175.254233.3.175.2554,094
60233.3.176.0/20233.3.176.1 to 233.3.191.254233.3.191.2554,094
61233.3.192.0/20233.3.192.1 to 233.3.207.254233.3.207.2554,094
62233.3.208.0/20233.3.208.1 to 233.3.223.254233.3.223.2554,094
63233.3.224.0/20233.3.224.1 to 233.3.239.254233.3.239.2554,094
64233.3.240.0/20233.3.240.1 to 233.3.255.254233.3.255.2554,094
65233.4.0.0/20233.4.0.1 to 233.4.15.254233.4.15.2554,094
66233.4.16.0/20233.4.16.1 to 233.4.31.254233.4.31.2554,094
67233.4.32.0/20233.4.32.1 to 233.4.47.254233.4.47.2554,094
68233.4.48.0/20233.4.48.1 to 233.4.63.254233.4.63.2554,094
69233.4.64.0/20233.4.64.1 to 233.4.79.254233.4.79.2554,094
70233.4.80.0/20233.4.80.1 to 233.4.95.254233.4.95.2554,094
71233.4.96.0/20233.4.96.1 to 233.4.111.254233.4.111.2554,094
72233.4.112.0/20233.4.112.1 to 233.4.127.254233.4.127.2554,094
73233.4.128.0/20233.4.128.1 to 233.4.143.254233.4.143.2554,094
74233.4.144.0/20233.4.144.1 to 233.4.159.254233.4.159.2554,094
75233.4.160.0/20233.4.160.1 to 233.4.175.254233.4.175.2554,094
76233.4.176.0/20233.4.176.1 to 233.4.191.254233.4.191.2554,094
77233.4.192.0/20233.4.192.1 to 233.4.207.254233.4.207.2554,094
78233.4.208.0/20233.4.208.1 to 233.4.223.254233.4.223.2554,094
79233.4.224.0/20233.4.224.1 to 233.4.239.254233.4.239.2554,094
80233.4.240.0/20233.4.240.1 to 233.4.255.254233.4.255.2554,094
81233.5.0.0/20233.5.0.1 to 233.5.15.254233.5.15.2554,094
82233.5.16.0/20233.5.16.1 to 233.5.31.254233.5.31.2554,094
83233.5.32.0/20233.5.32.1 to 233.5.47.254233.5.47.2554,094
84233.5.48.0/20233.5.48.1 to 233.5.63.254233.5.63.2554,094
85233.5.64.0/20233.5.64.1 to 233.5.79.254233.5.79.2554,094
86233.5.80.0/20233.5.80.1 to 233.5.95.254233.5.95.2554,094
87233.5.96.0/20233.5.96.1 to 233.5.111.254233.5.111.2554,094
88233.5.112.0/20233.5.112.1 to 233.5.127.254233.5.127.2554,094
89233.5.128.0/20233.5.128.1 to 233.5.143.254233.5.143.2554,094
90233.5.144.0/20233.5.144.1 to 233.5.159.254233.5.159.2554,094
91233.5.160.0/20233.5.160.1 to 233.5.175.254233.5.175.2554,094
92233.5.176.0/20233.5.176.1 to 233.5.191.254233.5.191.2554,094
93233.5.192.0/20233.5.192.1 to 233.5.207.254233.5.207.2554,094
94233.5.208.0/20233.5.208.1 to 233.5.223.254233.5.223.2554,094
95233.5.224.0/20233.5.224.1 to 233.5.239.254233.5.239.2554,094
96233.5.240.0/20233.5.240.1 to 233.5.255.254233.5.255.2554,094
97233.6.0.0/20233.6.0.1 to 233.6.15.254233.6.15.2554,094
98233.6.16.0/20233.6.16.1 to 233.6.31.254233.6.31.2554,094
99233.6.32.0/20233.6.32.1 to 233.6.47.254233.6.47.2554,094
100233.6.48.0/20233.6.48.1 to 233.6.63.254233.6.63.2554,094
101233.6.64.0/20233.6.64.1 to 233.6.79.254233.6.79.2554,094
102233.6.80.0/20233.6.80.1 to 233.6.95.254233.6.95.2554,094
103233.6.96.0/20233.6.96.1 to 233.6.111.254233.6.111.2554,094
104233.6.112.0/20233.6.112.1 to 233.6.127.254233.6.127.2554,094
105233.6.128.0/20233.6.128.1 to 233.6.143.254233.6.143.2554,094
106233.6.144.0/20233.6.144.1 to 233.6.159.254233.6.159.2554,094
107233.6.160.0/20233.6.160.1 to 233.6.175.254233.6.175.2554,094
108233.6.176.0/20233.6.176.1 to 233.6.191.254233.6.191.2554,094
109233.6.192.0/20233.6.192.1 to 233.6.207.254233.6.207.2554,094
110233.6.208.0/20233.6.208.1 to 233.6.223.254233.6.223.2554,094
111233.6.224.0/20233.6.224.1 to 233.6.239.254233.6.239.2554,094
112233.6.240.0/20233.6.240.1 to 233.6.255.254233.6.255.2554,094
113233.7.0.0/20233.7.0.1 to 233.7.15.254233.7.15.2554,094
114233.7.16.0/20233.7.16.1 to 233.7.31.254233.7.31.2554,094
115233.7.32.0/20233.7.32.1 to 233.7.47.254233.7.47.2554,094
116233.7.48.0/20233.7.48.1 to 233.7.63.254233.7.63.2554,094
117233.7.64.0/20233.7.64.1 to 233.7.79.254233.7.79.2554,094
118233.7.80.0/20233.7.80.1 to 233.7.95.254233.7.95.2554,094
119233.7.96.0/20233.7.96.1 to 233.7.111.254233.7.111.2554,094
120233.7.112.0/20233.7.112.1 to 233.7.127.254233.7.127.2554,094
121233.7.128.0/20233.7.128.1 to 233.7.143.254233.7.143.2554,094
122233.7.144.0/20233.7.144.1 to 233.7.159.254233.7.159.2554,094
123233.7.160.0/20233.7.160.1 to 233.7.175.254233.7.175.2554,094
124233.7.176.0/20233.7.176.1 to 233.7.191.254233.7.191.2554,094
125233.7.192.0/20233.7.192.1 to 233.7.207.254233.7.207.2554,094
126233.7.208.0/20233.7.208.1 to 233.7.223.254233.7.223.2554,094
127233.7.224.0/20233.7.224.1 to 233.7.239.254233.7.239.2554,094
128233.7.240.0/20233.7.240.1 to 233.7.255.254233.7.255.2554,094
129233.8.0.0/20233.8.0.1 to 233.8.15.254233.8.15.2554,094
130233.8.16.0/20233.8.16.1 to 233.8.31.254233.8.31.2554,094
131233.8.32.0/20233.8.32.1 to 233.8.47.254233.8.47.2554,094
132233.8.48.0/20233.8.48.1 to 233.8.63.254233.8.63.2554,094
133233.8.64.0/20233.8.64.1 to 233.8.79.254233.8.79.2554,094
134233.8.80.0/20233.8.80.1 to 233.8.95.254233.8.95.2554,094
135233.8.96.0/20233.8.96.1 to 233.8.111.254233.8.111.2554,094
136233.8.112.0/20233.8.112.1 to 233.8.127.254233.8.127.2554,094
137233.8.128.0/20233.8.128.1 to 233.8.143.254233.8.143.2554,094
138233.8.144.0/20233.8.144.1 to 233.8.159.254233.8.159.2554,094
139233.8.160.0/20233.8.160.1 to 233.8.175.254233.8.175.2554,094
140233.8.176.0/20233.8.176.1 to 233.8.191.254233.8.191.2554,094
141233.8.192.0/20233.8.192.1 to 233.8.207.254233.8.207.2554,094
142233.8.208.0/20233.8.208.1 to 233.8.223.254233.8.223.2554,094
143233.8.224.0/20233.8.224.1 to 233.8.239.254233.8.239.2554,094
144233.8.240.0/20233.8.240.1 to 233.8.255.254233.8.255.2554,094
145233.9.0.0/20233.9.0.1 to 233.9.15.254233.9.15.2554,094
146233.9.16.0/20233.9.16.1 to 233.9.31.254233.9.31.2554,094
147233.9.32.0/20233.9.32.1 to 233.9.47.254233.9.47.2554,094
148233.9.48.0/20233.9.48.1 to 233.9.63.254233.9.63.2554,094
149233.9.64.0/20233.9.64.1 to 233.9.79.254233.9.79.2554,094
150233.9.80.0/20233.9.80.1 to 233.9.95.254233.9.95.2554,094
151233.9.96.0/20233.9.96.1 to 233.9.111.254233.9.111.2554,094
152233.9.112.0/20233.9.112.1 to 233.9.127.254233.9.127.2554,094
153233.9.128.0/20233.9.128.1 to 233.9.143.254233.9.143.2554,094
154233.9.144.0/20233.9.144.1 to 233.9.159.254233.9.159.2554,094
155233.9.160.0/20233.9.160.1 to 233.9.175.254233.9.175.2554,094
156233.9.176.0/20233.9.176.1 to 233.9.191.254233.9.191.2554,094
157233.9.192.0/20233.9.192.1 to 233.9.207.254233.9.207.2554,094
158233.9.208.0/20233.9.208.1 to 233.9.223.254233.9.223.2554,094
159233.9.224.0/20233.9.224.1 to 233.9.239.254233.9.239.2554,094
160233.9.240.0/20233.9.240.1 to 233.9.255.254233.9.255.2554,094
161233.10.0.0/20233.10.0.1 to 233.10.15.254233.10.15.2554,094
162233.10.16.0/20233.10.16.1 to 233.10.31.254233.10.31.2554,094
163233.10.32.0/20233.10.32.1 to 233.10.47.254233.10.47.2554,094
164233.10.48.0/20233.10.48.1 to 233.10.63.254233.10.63.2554,094
165233.10.64.0/20233.10.64.1 to 233.10.79.254233.10.79.2554,094
166233.10.80.0/20233.10.80.1 to 233.10.95.254233.10.95.2554,094
167233.10.96.0/20233.10.96.1 to 233.10.111.254233.10.111.2554,094
168233.10.112.0/20233.10.112.1 to 233.10.127.254233.10.127.2554,094
169233.10.128.0/20233.10.128.1 to 233.10.143.254233.10.143.2554,094
170233.10.144.0/20233.10.144.1 to 233.10.159.254233.10.159.2554,094
171233.10.160.0/20233.10.160.1 to 233.10.175.254233.10.175.2554,094
172233.10.176.0/20233.10.176.1 to 233.10.191.254233.10.191.2554,094
173233.10.192.0/20233.10.192.1 to 233.10.207.254233.10.207.2554,094
174233.10.208.0/20233.10.208.1 to 233.10.223.254233.10.223.2554,094
175233.10.224.0/20233.10.224.1 to 233.10.239.254233.10.239.2554,094
176233.10.240.0/20233.10.240.1 to 233.10.255.254233.10.255.2554,094
177233.11.0.0/20233.11.0.1 to 233.11.15.254233.11.15.2554,094
178233.11.16.0/20233.11.16.1 to 233.11.31.254233.11.31.2554,094
179233.11.32.0/20233.11.32.1 to 233.11.47.254233.11.47.2554,094
180233.11.48.0/20233.11.48.1 to 233.11.63.254233.11.63.2554,094
181233.11.64.0/20233.11.64.1 to 233.11.79.254233.11.79.2554,094
182233.11.80.0/20233.11.80.1 to 233.11.95.254233.11.95.2554,094
183233.11.96.0/20233.11.96.1 to 233.11.111.254233.11.111.2554,094
184233.11.112.0/20233.11.112.1 to 233.11.127.254233.11.127.2554,094
185233.11.128.0/20233.11.128.1 to 233.11.143.254233.11.143.2554,094
186233.11.144.0/20233.11.144.1 to 233.11.159.254233.11.159.2554,094
187233.11.160.0/20233.11.160.1 to 233.11.175.254233.11.175.2554,094
188233.11.176.0/20233.11.176.1 to 233.11.191.254233.11.191.2554,094
189233.11.192.0/20233.11.192.1 to 233.11.207.254233.11.207.2554,094
190233.11.208.0/20233.11.208.1 to 233.11.223.254233.11.223.2554,094
191233.11.224.0/20233.11.224.1 to 233.11.239.254233.11.239.2554,094
192233.11.240.0/20233.11.240.1 to 233.11.255.254233.11.255.2554,094
193233.12.0.0/20233.12.0.1 to 233.12.15.254233.12.15.2554,094
194233.12.16.0/20233.12.16.1 to 233.12.31.254233.12.31.2554,094
195233.12.32.0/20233.12.32.1 to 233.12.47.254233.12.47.2554,094
196233.12.48.0/20233.12.48.1 to 233.12.63.254233.12.63.2554,094
197233.12.64.0/20233.12.64.1 to 233.12.79.254233.12.79.2554,094
198233.12.80.0/20233.12.80.1 to 233.12.95.254233.12.95.2554,094
199233.12.96.0/20233.12.96.1 to 233.12.111.254233.12.111.2554,094
200233.12.112.0/20233.12.112.1 to 233.12.127.254233.12.127.2554,094
201233.12.128.0/20233.12.128.1 to 233.12.143.254233.12.143.2554,094
202233.12.144.0/20233.12.144.1 to 233.12.159.254233.12.159.2554,094
203233.12.160.0/20233.12.160.1 to 233.12.175.254233.12.175.2554,094
204233.12.176.0/20233.12.176.1 to 233.12.191.254233.12.191.2554,094
205233.12.192.0/20233.12.192.1 to 233.12.207.254233.12.207.2554,094
206233.12.208.0/20233.12.208.1 to 233.12.223.254233.12.223.2554,094
207233.12.224.0/20233.12.224.1 to 233.12.239.254233.12.239.2554,094
208233.12.240.0/20233.12.240.1 to 233.12.255.254233.12.255.2554,094
209233.13.0.0/20233.13.0.1 to 233.13.15.254233.13.15.2554,094
210233.13.16.0/20233.13.16.1 to 233.13.31.254233.13.31.2554,094
211233.13.32.0/20233.13.32.1 to 233.13.47.254233.13.47.2554,094
212233.13.48.0/20233.13.48.1 to 233.13.63.254233.13.63.2554,094
213233.13.64.0/20233.13.64.1 to 233.13.79.254233.13.79.2554,094
214233.13.80.0/20233.13.80.1 to 233.13.95.254233.13.95.2554,094
215233.13.96.0/20233.13.96.1 to 233.13.111.254233.13.111.2554,094
216233.13.112.0/20233.13.112.1 to 233.13.127.254233.13.127.2554,094
217233.13.128.0/20233.13.128.1 to 233.13.143.254233.13.143.2554,094
218233.13.144.0/20233.13.144.1 to 233.13.159.254233.13.159.2554,094
219233.13.160.0/20233.13.160.1 to 233.13.175.254233.13.175.2554,094
220233.13.176.0/20233.13.176.1 to 233.13.191.254233.13.191.2554,094
221233.13.192.0/20233.13.192.1 to 233.13.207.254233.13.207.2554,094
222233.13.208.0/20233.13.208.1 to 233.13.223.254233.13.223.2554,094
223233.13.224.0/20233.13.224.1 to 233.13.239.254233.13.239.2554,094
224233.13.240.0/20233.13.240.1 to 233.13.255.254233.13.255.2554,094
225233.14.0.0/20233.14.0.1 to 233.14.15.254233.14.15.2554,094
226233.14.16.0/20233.14.16.1 to 233.14.31.254233.14.31.2554,094
227233.14.32.0/20233.14.32.1 to 233.14.47.254233.14.47.2554,094
228233.14.48.0/20233.14.48.1 to 233.14.63.254233.14.63.2554,094
229233.14.64.0/20233.14.64.1 to 233.14.79.254233.14.79.2554,094
230233.14.80.0/20233.14.80.1 to 233.14.95.254233.14.95.2554,094
231233.14.96.0/20233.14.96.1 to 233.14.111.254233.14.111.2554,094
232233.14.112.0/20233.14.112.1 to 233.14.127.254233.14.127.2554,094
233233.14.128.0/20233.14.128.1 to 233.14.143.254233.14.143.2554,094
234233.14.144.0/20233.14.144.1 to 233.14.159.254233.14.159.2554,094
235233.14.160.0/20233.14.160.1 to 233.14.175.254233.14.175.2554,094
236233.14.176.0/20233.14.176.1 to 233.14.191.254233.14.191.2554,094
237233.14.192.0/20233.14.192.1 to 233.14.207.254233.14.207.2554,094
238233.14.208.0/20233.14.208.1 to 233.14.223.254233.14.223.2554,094
239233.14.224.0/20233.14.224.1 to 233.14.239.254233.14.239.2554,094
240233.14.240.0/20233.14.240.1 to 233.14.255.254233.14.255.2554,094
241233.15.0.0/20233.15.0.1 to 233.15.15.254233.15.15.2554,094
242233.15.16.0/20233.15.16.1 to 233.15.31.254233.15.31.2554,094
243233.15.32.0/20233.15.32.1 to 233.15.47.254233.15.47.2554,094
244233.15.48.0/20233.15.48.1 to 233.15.63.254233.15.63.2554,094
245233.15.64.0/20233.15.64.1 to 233.15.79.254233.15.79.2554,094
246233.15.80.0/20233.15.80.1 to 233.15.95.254233.15.95.2554,094
247233.15.96.0/20233.15.96.1 to 233.15.111.254233.15.111.2554,094
248233.15.112.0/20233.15.112.1 to 233.15.127.254233.15.127.2554,094
249233.15.128.0/20233.15.128.1 to 233.15.143.254233.15.143.2554,094
250233.15.144.0/20233.15.144.1 to 233.15.159.254233.15.159.2554,094
251233.15.160.0/20233.15.160.1 to 233.15.175.254233.15.175.2554,094
252233.15.176.0/20233.15.176.1 to 233.15.191.254233.15.191.2554,094
253233.15.192.0/20233.15.192.1 to 233.15.207.254233.15.207.2554,094
254233.15.208.0/20233.15.208.1 to 233.15.223.254233.15.223.2554,094
255233.15.224.0/20233.15.224.1 to 233.15.239.254233.15.239.2554,094
256233.15.240.0/20233.15.240.1 to 233.15.255.254233.15.255.2554,094

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.