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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.

Network230.128.0.0/11
Usable hosts2,097,150
Subnet mask255.224.0.0
Addresses2,097,152
Network address
230.128.0.0
Broadcast address
230.159.255.255
First usable
230.128.0.1
Last usable
230.159.255.254
Usable hosts
2,097,150 (2,097,152 less the network and broadcast addresses)
Subnet mask
255.224.0.0
Wildcard mask
0.31.255.255 (Cisco ACLs, OSPF)
Prefix length
/11
Type
Multicast 224.0.0.0/4
One-to-many traffic, such as IPTV and routing protocols
Old class
D (multicast)
As numbers
Hex E6800000 · Integer 3867148288 to 3869245439
Reverse DNS zones
128.230.in-addr.arpa
129.230.in-addr.arpa
130.230.in-addr.arpa
131.230.in-addr.arpa
132.230.in-addr.arpa
133.230.in-addr.arpa
134.230.in-addr.arpa
135.230.in-addr.arpa
136.230.in-addr.arpa
137.230.in-addr.arpa
138.230.in-addr.arpa
139.230.in-addr.arpa
140.230.in-addr.arpa
141.230.in-addr.arpa
142.230.in-addr.arpa
143.230.in-addr.arpa
and 16 more
/11 is not on a 8-bit boundary, so it takes 32 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11100110.10000000.00000000.00000000230.128.0.0
Subnet mask11111111.11100000.00000000.00000000255.224.0.0
Network11100110.10000000.00000000.00000000230.128.0.0
Broadcast11100110.10011111.11111111.11111111230.159.255.255
Split into smaller subnets/21
/12 (2)/13 (4)/14 (8)/15 (16)/16 (32)/17 (64)/18 (128)/19 (256)/20 (512)/21 (1,024)/22 (2,048)/23 (4,096)

230.128.0.0/11 makes 1,024 subnets of /21; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1230.128.0.0/21230.128.0.1 to 230.128.7.254230.128.7.2552,046
2230.128.8.0/21230.128.8.1 to 230.128.15.254230.128.15.2552,046
3230.128.16.0/21230.128.16.1 to 230.128.23.254230.128.23.2552,046
4230.128.24.0/21230.128.24.1 to 230.128.31.254230.128.31.2552,046
5230.128.32.0/21230.128.32.1 to 230.128.39.254230.128.39.2552,046
6230.128.40.0/21230.128.40.1 to 230.128.47.254230.128.47.2552,046
7230.128.48.0/21230.128.48.1 to 230.128.55.254230.128.55.2552,046
8230.128.56.0/21230.128.56.1 to 230.128.63.254230.128.63.2552,046
9230.128.64.0/21230.128.64.1 to 230.128.71.254230.128.71.2552,046
10230.128.72.0/21230.128.72.1 to 230.128.79.254230.128.79.2552,046
11230.128.80.0/21230.128.80.1 to 230.128.87.254230.128.87.2552,046
12230.128.88.0/21230.128.88.1 to 230.128.95.254230.128.95.2552,046
13230.128.96.0/21230.128.96.1 to 230.128.103.254230.128.103.2552,046
14230.128.104.0/21230.128.104.1 to 230.128.111.254230.128.111.2552,046
15230.128.112.0/21230.128.112.1 to 230.128.119.254230.128.119.2552,046
16230.128.120.0/21230.128.120.1 to 230.128.127.254230.128.127.2552,046
17230.128.128.0/21230.128.128.1 to 230.128.135.254230.128.135.2552,046
18230.128.136.0/21230.128.136.1 to 230.128.143.254230.128.143.2552,046
19230.128.144.0/21230.128.144.1 to 230.128.151.254230.128.151.2552,046
20230.128.152.0/21230.128.152.1 to 230.128.159.254230.128.159.2552,046
21230.128.160.0/21230.128.160.1 to 230.128.167.254230.128.167.2552,046
22230.128.168.0/21230.128.168.1 to 230.128.175.254230.128.175.2552,046
23230.128.176.0/21230.128.176.1 to 230.128.183.254230.128.183.2552,046
24230.128.184.0/21230.128.184.1 to 230.128.191.254230.128.191.2552,046
25230.128.192.0/21230.128.192.1 to 230.128.199.254230.128.199.2552,046
26230.128.200.0/21230.128.200.1 to 230.128.207.254230.128.207.2552,046
27230.128.208.0/21230.128.208.1 to 230.128.215.254230.128.215.2552,046
28230.128.216.0/21230.128.216.1 to 230.128.223.254230.128.223.2552,046
29230.128.224.0/21230.128.224.1 to 230.128.231.254230.128.231.2552,046
30230.128.232.0/21230.128.232.1 to 230.128.239.254230.128.239.2552,046
31230.128.240.0/21230.128.240.1 to 230.128.247.254230.128.247.2552,046
32230.128.248.0/21230.128.248.1 to 230.128.255.254230.128.255.2552,046
33230.129.0.0/21230.129.0.1 to 230.129.7.254230.129.7.2552,046
34230.129.8.0/21230.129.8.1 to 230.129.15.254230.129.15.2552,046
35230.129.16.0/21230.129.16.1 to 230.129.23.254230.129.23.2552,046
36230.129.24.0/21230.129.24.1 to 230.129.31.254230.129.31.2552,046
37230.129.32.0/21230.129.32.1 to 230.129.39.254230.129.39.2552,046
38230.129.40.0/21230.129.40.1 to 230.129.47.254230.129.47.2552,046
39230.129.48.0/21230.129.48.1 to 230.129.55.254230.129.55.2552,046
40230.129.56.0/21230.129.56.1 to 230.129.63.254230.129.63.2552,046
41230.129.64.0/21230.129.64.1 to 230.129.71.254230.129.71.2552,046
42230.129.72.0/21230.129.72.1 to 230.129.79.254230.129.79.2552,046
43230.129.80.0/21230.129.80.1 to 230.129.87.254230.129.87.2552,046
44230.129.88.0/21230.129.88.1 to 230.129.95.254230.129.95.2552,046
45230.129.96.0/21230.129.96.1 to 230.129.103.254230.129.103.2552,046
46230.129.104.0/21230.129.104.1 to 230.129.111.254230.129.111.2552,046
47230.129.112.0/21230.129.112.1 to 230.129.119.254230.129.119.2552,046
48230.129.120.0/21230.129.120.1 to 230.129.127.254230.129.127.2552,046
49230.129.128.0/21230.129.128.1 to 230.129.135.254230.129.135.2552,046
50230.129.136.0/21230.129.136.1 to 230.129.143.254230.129.143.2552,046
51230.129.144.0/21230.129.144.1 to 230.129.151.254230.129.151.2552,046
52230.129.152.0/21230.129.152.1 to 230.129.159.254230.129.159.2552,046
53230.129.160.0/21230.129.160.1 to 230.129.167.254230.129.167.2552,046
54230.129.168.0/21230.129.168.1 to 230.129.175.254230.129.175.2552,046
55230.129.176.0/21230.129.176.1 to 230.129.183.254230.129.183.2552,046
56230.129.184.0/21230.129.184.1 to 230.129.191.254230.129.191.2552,046
57230.129.192.0/21230.129.192.1 to 230.129.199.254230.129.199.2552,046
58230.129.200.0/21230.129.200.1 to 230.129.207.254230.129.207.2552,046
59230.129.208.0/21230.129.208.1 to 230.129.215.254230.129.215.2552,046
60230.129.216.0/21230.129.216.1 to 230.129.223.254230.129.223.2552,046
61230.129.224.0/21230.129.224.1 to 230.129.231.254230.129.231.2552,046
62230.129.232.0/21230.129.232.1 to 230.129.239.254230.129.239.2552,046
63230.129.240.0/21230.129.240.1 to 230.129.247.254230.129.247.2552,046
64230.129.248.0/21230.129.248.1 to 230.129.255.254230.129.255.2552,046
65230.130.0.0/21230.130.0.1 to 230.130.7.254230.130.7.2552,046
66230.130.8.0/21230.130.8.1 to 230.130.15.254230.130.15.2552,046
67230.130.16.0/21230.130.16.1 to 230.130.23.254230.130.23.2552,046
68230.130.24.0/21230.130.24.1 to 230.130.31.254230.130.31.2552,046
69230.130.32.0/21230.130.32.1 to 230.130.39.254230.130.39.2552,046
70230.130.40.0/21230.130.40.1 to 230.130.47.254230.130.47.2552,046
71230.130.48.0/21230.130.48.1 to 230.130.55.254230.130.55.2552,046
72230.130.56.0/21230.130.56.1 to 230.130.63.254230.130.63.2552,046
73230.130.64.0/21230.130.64.1 to 230.130.71.254230.130.71.2552,046
74230.130.72.0/21230.130.72.1 to 230.130.79.254230.130.79.2552,046
75230.130.80.0/21230.130.80.1 to 230.130.87.254230.130.87.2552,046
76230.130.88.0/21230.130.88.1 to 230.130.95.254230.130.95.2552,046
77230.130.96.0/21230.130.96.1 to 230.130.103.254230.130.103.2552,046
78230.130.104.0/21230.130.104.1 to 230.130.111.254230.130.111.2552,046
79230.130.112.0/21230.130.112.1 to 230.130.119.254230.130.119.2552,046
80230.130.120.0/21230.130.120.1 to 230.130.127.254230.130.127.2552,046
81230.130.128.0/21230.130.128.1 to 230.130.135.254230.130.135.2552,046
82230.130.136.0/21230.130.136.1 to 230.130.143.254230.130.143.2552,046
83230.130.144.0/21230.130.144.1 to 230.130.151.254230.130.151.2552,046
84230.130.152.0/21230.130.152.1 to 230.130.159.254230.130.159.2552,046
85230.130.160.0/21230.130.160.1 to 230.130.167.254230.130.167.2552,046
86230.130.168.0/21230.130.168.1 to 230.130.175.254230.130.175.2552,046
87230.130.176.0/21230.130.176.1 to 230.130.183.254230.130.183.2552,046
88230.130.184.0/21230.130.184.1 to 230.130.191.254230.130.191.2552,046
89230.130.192.0/21230.130.192.1 to 230.130.199.254230.130.199.2552,046
90230.130.200.0/21230.130.200.1 to 230.130.207.254230.130.207.2552,046
91230.130.208.0/21230.130.208.1 to 230.130.215.254230.130.215.2552,046
92230.130.216.0/21230.130.216.1 to 230.130.223.254230.130.223.2552,046
93230.130.224.0/21230.130.224.1 to 230.130.231.254230.130.231.2552,046
94230.130.232.0/21230.130.232.1 to 230.130.239.254230.130.239.2552,046
95230.130.240.0/21230.130.240.1 to 230.130.247.254230.130.247.2552,046
96230.130.248.0/21230.130.248.1 to 230.130.255.254230.130.255.2552,046
97230.131.0.0/21230.131.0.1 to 230.131.7.254230.131.7.2552,046
98230.131.8.0/21230.131.8.1 to 230.131.15.254230.131.15.2552,046
99230.131.16.0/21230.131.16.1 to 230.131.23.254230.131.23.2552,046
100230.131.24.0/21230.131.24.1 to 230.131.31.254230.131.31.2552,046
101230.131.32.0/21230.131.32.1 to 230.131.39.254230.131.39.2552,046
102230.131.40.0/21230.131.40.1 to 230.131.47.254230.131.47.2552,046
103230.131.48.0/21230.131.48.1 to 230.131.55.254230.131.55.2552,046
104230.131.56.0/21230.131.56.1 to 230.131.63.254230.131.63.2552,046
105230.131.64.0/21230.131.64.1 to 230.131.71.254230.131.71.2552,046
106230.131.72.0/21230.131.72.1 to 230.131.79.254230.131.79.2552,046
107230.131.80.0/21230.131.80.1 to 230.131.87.254230.131.87.2552,046
108230.131.88.0/21230.131.88.1 to 230.131.95.254230.131.95.2552,046
109230.131.96.0/21230.131.96.1 to 230.131.103.254230.131.103.2552,046
110230.131.104.0/21230.131.104.1 to 230.131.111.254230.131.111.2552,046
111230.131.112.0/21230.131.112.1 to 230.131.119.254230.131.119.2552,046
112230.131.120.0/21230.131.120.1 to 230.131.127.254230.131.127.2552,046
113230.131.128.0/21230.131.128.1 to 230.131.135.254230.131.135.2552,046
114230.131.136.0/21230.131.136.1 to 230.131.143.254230.131.143.2552,046
115230.131.144.0/21230.131.144.1 to 230.131.151.254230.131.151.2552,046
116230.131.152.0/21230.131.152.1 to 230.131.159.254230.131.159.2552,046
117230.131.160.0/21230.131.160.1 to 230.131.167.254230.131.167.2552,046
118230.131.168.0/21230.131.168.1 to 230.131.175.254230.131.175.2552,046
119230.131.176.0/21230.131.176.1 to 230.131.183.254230.131.183.2552,046
120230.131.184.0/21230.131.184.1 to 230.131.191.254230.131.191.2552,046
121230.131.192.0/21230.131.192.1 to 230.131.199.254230.131.199.2552,046
122230.131.200.0/21230.131.200.1 to 230.131.207.254230.131.207.2552,046
123230.131.208.0/21230.131.208.1 to 230.131.215.254230.131.215.2552,046
124230.131.216.0/21230.131.216.1 to 230.131.223.254230.131.223.2552,046
125230.131.224.0/21230.131.224.1 to 230.131.231.254230.131.231.2552,046
126230.131.232.0/21230.131.232.1 to 230.131.239.254230.131.239.2552,046
127230.131.240.0/21230.131.240.1 to 230.131.247.254230.131.247.2552,046
128230.131.248.0/21230.131.248.1 to 230.131.255.254230.131.255.2552,046
129230.132.0.0/21230.132.0.1 to 230.132.7.254230.132.7.2552,046
130230.132.8.0/21230.132.8.1 to 230.132.15.254230.132.15.2552,046
131230.132.16.0/21230.132.16.1 to 230.132.23.254230.132.23.2552,046
132230.132.24.0/21230.132.24.1 to 230.132.31.254230.132.31.2552,046
133230.132.32.0/21230.132.32.1 to 230.132.39.254230.132.39.2552,046
134230.132.40.0/21230.132.40.1 to 230.132.47.254230.132.47.2552,046
135230.132.48.0/21230.132.48.1 to 230.132.55.254230.132.55.2552,046
136230.132.56.0/21230.132.56.1 to 230.132.63.254230.132.63.2552,046
137230.132.64.0/21230.132.64.1 to 230.132.71.254230.132.71.2552,046
138230.132.72.0/21230.132.72.1 to 230.132.79.254230.132.79.2552,046
139230.132.80.0/21230.132.80.1 to 230.132.87.254230.132.87.2552,046
140230.132.88.0/21230.132.88.1 to 230.132.95.254230.132.95.2552,046
141230.132.96.0/21230.132.96.1 to 230.132.103.254230.132.103.2552,046
142230.132.104.0/21230.132.104.1 to 230.132.111.254230.132.111.2552,046
143230.132.112.0/21230.132.112.1 to 230.132.119.254230.132.119.2552,046
144230.132.120.0/21230.132.120.1 to 230.132.127.254230.132.127.2552,046
145230.132.128.0/21230.132.128.1 to 230.132.135.254230.132.135.2552,046
146230.132.136.0/21230.132.136.1 to 230.132.143.254230.132.143.2552,046
147230.132.144.0/21230.132.144.1 to 230.132.151.254230.132.151.2552,046
148230.132.152.0/21230.132.152.1 to 230.132.159.254230.132.159.2552,046
149230.132.160.0/21230.132.160.1 to 230.132.167.254230.132.167.2552,046
150230.132.168.0/21230.132.168.1 to 230.132.175.254230.132.175.2552,046
151230.132.176.0/21230.132.176.1 to 230.132.183.254230.132.183.2552,046
152230.132.184.0/21230.132.184.1 to 230.132.191.254230.132.191.2552,046
153230.132.192.0/21230.132.192.1 to 230.132.199.254230.132.199.2552,046
154230.132.200.0/21230.132.200.1 to 230.132.207.254230.132.207.2552,046
155230.132.208.0/21230.132.208.1 to 230.132.215.254230.132.215.2552,046
156230.132.216.0/21230.132.216.1 to 230.132.223.254230.132.223.2552,046
157230.132.224.0/21230.132.224.1 to 230.132.231.254230.132.231.2552,046
158230.132.232.0/21230.132.232.1 to 230.132.239.254230.132.239.2552,046
159230.132.240.0/21230.132.240.1 to 230.132.247.254230.132.247.2552,046
160230.132.248.0/21230.132.248.1 to 230.132.255.254230.132.255.2552,046
161230.133.0.0/21230.133.0.1 to 230.133.7.254230.133.7.2552,046
162230.133.8.0/21230.133.8.1 to 230.133.15.254230.133.15.2552,046
163230.133.16.0/21230.133.16.1 to 230.133.23.254230.133.23.2552,046
164230.133.24.0/21230.133.24.1 to 230.133.31.254230.133.31.2552,046
165230.133.32.0/21230.133.32.1 to 230.133.39.254230.133.39.2552,046
166230.133.40.0/21230.133.40.1 to 230.133.47.254230.133.47.2552,046
167230.133.48.0/21230.133.48.1 to 230.133.55.254230.133.55.2552,046
168230.133.56.0/21230.133.56.1 to 230.133.63.254230.133.63.2552,046
169230.133.64.0/21230.133.64.1 to 230.133.71.254230.133.71.2552,046
170230.133.72.0/21230.133.72.1 to 230.133.79.254230.133.79.2552,046
171230.133.80.0/21230.133.80.1 to 230.133.87.254230.133.87.2552,046
172230.133.88.0/21230.133.88.1 to 230.133.95.254230.133.95.2552,046
173230.133.96.0/21230.133.96.1 to 230.133.103.254230.133.103.2552,046
174230.133.104.0/21230.133.104.1 to 230.133.111.254230.133.111.2552,046
175230.133.112.0/21230.133.112.1 to 230.133.119.254230.133.119.2552,046
176230.133.120.0/21230.133.120.1 to 230.133.127.254230.133.127.2552,046
177230.133.128.0/21230.133.128.1 to 230.133.135.254230.133.135.2552,046
178230.133.136.0/21230.133.136.1 to 230.133.143.254230.133.143.2552,046
179230.133.144.0/21230.133.144.1 to 230.133.151.254230.133.151.2552,046
180230.133.152.0/21230.133.152.1 to 230.133.159.254230.133.159.2552,046
181230.133.160.0/21230.133.160.1 to 230.133.167.254230.133.167.2552,046
182230.133.168.0/21230.133.168.1 to 230.133.175.254230.133.175.2552,046
183230.133.176.0/21230.133.176.1 to 230.133.183.254230.133.183.2552,046
184230.133.184.0/21230.133.184.1 to 230.133.191.254230.133.191.2552,046
185230.133.192.0/21230.133.192.1 to 230.133.199.254230.133.199.2552,046
186230.133.200.0/21230.133.200.1 to 230.133.207.254230.133.207.2552,046
187230.133.208.0/21230.133.208.1 to 230.133.215.254230.133.215.2552,046
188230.133.216.0/21230.133.216.1 to 230.133.223.254230.133.223.2552,046
189230.133.224.0/21230.133.224.1 to 230.133.231.254230.133.231.2552,046
190230.133.232.0/21230.133.232.1 to 230.133.239.254230.133.239.2552,046
191230.133.240.0/21230.133.240.1 to 230.133.247.254230.133.247.2552,046
192230.133.248.0/21230.133.248.1 to 230.133.255.254230.133.255.2552,046
193230.134.0.0/21230.134.0.1 to 230.134.7.254230.134.7.2552,046
194230.134.8.0/21230.134.8.1 to 230.134.15.254230.134.15.2552,046
195230.134.16.0/21230.134.16.1 to 230.134.23.254230.134.23.2552,046
196230.134.24.0/21230.134.24.1 to 230.134.31.254230.134.31.2552,046
197230.134.32.0/21230.134.32.1 to 230.134.39.254230.134.39.2552,046
198230.134.40.0/21230.134.40.1 to 230.134.47.254230.134.47.2552,046
199230.134.48.0/21230.134.48.1 to 230.134.55.254230.134.55.2552,046
200230.134.56.0/21230.134.56.1 to 230.134.63.254230.134.63.2552,046
201230.134.64.0/21230.134.64.1 to 230.134.71.254230.134.71.2552,046
202230.134.72.0/21230.134.72.1 to 230.134.79.254230.134.79.2552,046
203230.134.80.0/21230.134.80.1 to 230.134.87.254230.134.87.2552,046
204230.134.88.0/21230.134.88.1 to 230.134.95.254230.134.95.2552,046
205230.134.96.0/21230.134.96.1 to 230.134.103.254230.134.103.2552,046
206230.134.104.0/21230.134.104.1 to 230.134.111.254230.134.111.2552,046
207230.134.112.0/21230.134.112.1 to 230.134.119.254230.134.119.2552,046
208230.134.120.0/21230.134.120.1 to 230.134.127.254230.134.127.2552,046
209230.134.128.0/21230.134.128.1 to 230.134.135.254230.134.135.2552,046
210230.134.136.0/21230.134.136.1 to 230.134.143.254230.134.143.2552,046
211230.134.144.0/21230.134.144.1 to 230.134.151.254230.134.151.2552,046
212230.134.152.0/21230.134.152.1 to 230.134.159.254230.134.159.2552,046
213230.134.160.0/21230.134.160.1 to 230.134.167.254230.134.167.2552,046
214230.134.168.0/21230.134.168.1 to 230.134.175.254230.134.175.2552,046
215230.134.176.0/21230.134.176.1 to 230.134.183.254230.134.183.2552,046
216230.134.184.0/21230.134.184.1 to 230.134.191.254230.134.191.2552,046
217230.134.192.0/21230.134.192.1 to 230.134.199.254230.134.199.2552,046
218230.134.200.0/21230.134.200.1 to 230.134.207.254230.134.207.2552,046
219230.134.208.0/21230.134.208.1 to 230.134.215.254230.134.215.2552,046
220230.134.216.0/21230.134.216.1 to 230.134.223.254230.134.223.2552,046
221230.134.224.0/21230.134.224.1 to 230.134.231.254230.134.231.2552,046
222230.134.232.0/21230.134.232.1 to 230.134.239.254230.134.239.2552,046
223230.134.240.0/21230.134.240.1 to 230.134.247.254230.134.247.2552,046
224230.134.248.0/21230.134.248.1 to 230.134.255.254230.134.255.2552,046
225230.135.0.0/21230.135.0.1 to 230.135.7.254230.135.7.2552,046
226230.135.8.0/21230.135.8.1 to 230.135.15.254230.135.15.2552,046
227230.135.16.0/21230.135.16.1 to 230.135.23.254230.135.23.2552,046
228230.135.24.0/21230.135.24.1 to 230.135.31.254230.135.31.2552,046
229230.135.32.0/21230.135.32.1 to 230.135.39.254230.135.39.2552,046
230230.135.40.0/21230.135.40.1 to 230.135.47.254230.135.47.2552,046
231230.135.48.0/21230.135.48.1 to 230.135.55.254230.135.55.2552,046
232230.135.56.0/21230.135.56.1 to 230.135.63.254230.135.63.2552,046
233230.135.64.0/21230.135.64.1 to 230.135.71.254230.135.71.2552,046
234230.135.72.0/21230.135.72.1 to 230.135.79.254230.135.79.2552,046
235230.135.80.0/21230.135.80.1 to 230.135.87.254230.135.87.2552,046
236230.135.88.0/21230.135.88.1 to 230.135.95.254230.135.95.2552,046
237230.135.96.0/21230.135.96.1 to 230.135.103.254230.135.103.2552,046
238230.135.104.0/21230.135.104.1 to 230.135.111.254230.135.111.2552,046
239230.135.112.0/21230.135.112.1 to 230.135.119.254230.135.119.2552,046
240230.135.120.0/21230.135.120.1 to 230.135.127.254230.135.127.2552,046
241230.135.128.0/21230.135.128.1 to 230.135.135.254230.135.135.2552,046
242230.135.136.0/21230.135.136.1 to 230.135.143.254230.135.143.2552,046
243230.135.144.0/21230.135.144.1 to 230.135.151.254230.135.151.2552,046
244230.135.152.0/21230.135.152.1 to 230.135.159.254230.135.159.2552,046
245230.135.160.0/21230.135.160.1 to 230.135.167.254230.135.167.2552,046
246230.135.168.0/21230.135.168.1 to 230.135.175.254230.135.175.2552,046
247230.135.176.0/21230.135.176.1 to 230.135.183.254230.135.183.2552,046
248230.135.184.0/21230.135.184.1 to 230.135.191.254230.135.191.2552,046
249230.135.192.0/21230.135.192.1 to 230.135.199.254230.135.199.2552,046
250230.135.200.0/21230.135.200.1 to 230.135.207.254230.135.207.2552,046
251230.135.208.0/21230.135.208.1 to 230.135.215.254230.135.215.2552,046
252230.135.216.0/21230.135.216.1 to 230.135.223.254230.135.223.2552,046
253230.135.224.0/21230.135.224.1 to 230.135.231.254230.135.231.2552,046
254230.135.232.0/21230.135.232.1 to 230.135.239.254230.135.239.2552,046
255230.135.240.0/21230.135.240.1 to 230.135.247.254230.135.247.2552,046
256230.135.248.0/21230.135.248.1 to 230.135.255.254230.135.255.2552,046

IPv4 CIDR reference (/0 to /32)

IPv4 prefix lengths
PrefixSubnet maskWildcardAddressesUsable hostsSizeTypical use
/00.0.0.0255.255.255.2554,294,967,2964,294,967,29416,777,216 × /24
/1128.0.0.0127.255.255.2552,147,483,6482,147,483,6468,388,608 × /24
/2192.0.0.063.255.255.2551,073,741,8241,073,741,8224,194,304 × /24
/3224.0.0.031.255.255.255536,870,912536,870,9102,097,152 × /24
/4240.0.0.015.255.255.255268,435,456268,435,4541,048,576 × /24
/5248.0.0.07.255.255.255134,217,728134,217,726524,288 × /24
/6252.0.0.03.255.255.25567,108,86467,108,862262,144 × /24
/7254.0.0.01.255.255.25533,554,43233,554,430131,072 × /24
/8255.0.0.00.255.255.25516,777,21616,777,21465,536 × /24Old class A; 10.0.0.0/8
/9255.128.0.00.127.255.2558,388,6088,388,60632,768 × /24
/10255.192.0.00.63.255.2554,194,3044,194,30216,384 × /24
/11255.224.0.00.31.255.2552,097,1522,097,1508,192 × /24
/12255.240.0.00.15.255.2551,048,5761,048,5744,096 × /24172.16.0.0/12
/13255.248.0.00.7.255.255524,288524,2862,048 × /24
/14255.252.0.00.3.255.255262,144262,1421,024 × /24
/15255.254.0.00.1.255.255131,072131,070512 × /24
/16255.255.0.00.0.255.25565,53665,534256 × /24Old class B; 192.168.0.0/16
/17255.255.128.00.0.127.25532,76832,766128 × /24
/18255.255.192.00.0.63.25516,38416,38264 × /24
/19255.255.224.00.0.31.2558,1928,19032 × /24
/20255.255.240.00.0.15.2554,0964,09416 × /24
/21255.255.248.00.0.7.2552,0482,0468 × /24
/22255.255.252.00.0.3.2551,0241,0224 × /24Large office or guest Wi-Fi (1,022 hosts)
/23255.255.254.00.0.1.2555125102 × /24Larger office LAN (510 hosts)
/24255.255.255.00.0.0.2552562541 × /24Typical office LAN (old class C)
/25255.255.255.1280.0.0.1271281261/2 of a /24Smaller LAN or VLAN
/26255.255.255.1920.0.0.6364621/4 of a /24Smaller LAN or VLAN
/27255.255.255.2240.0.0.3132301/8 of a /24Small VLAN, phones, cameras
/28255.255.255.2400.0.0.1516141/16 of a /24Small VLAN, phones, cameras
/29255.255.255.2480.0.0.7861/32 of a /24Small fixed public block (5 usable)
/30255.255.255.2520.0.0.3421/64 of a /24Point-to-point (old style)
/31255.255.255.2540.0.0.1221/128 of a /24Point-to-point link (RFC 3021)
/32255.255.255.2550.0.0.0111/256 of a /24One host

IPv6 prefix reference

IPv6 prefix lengths
PrefixAddresses/64 LANs/48 sitesNibbleTypical use
/342,535,295,865,117,307,932,921,825,928,971,026,432 (2^125)2,305,843,009,213,693,95235,184,372,088,832NoAll global unicast (2000::/3)
/165,192,296,858,534,827,628,530,496,329,220,096 (2^112)281,474,976,710,6564,294,967,296Yes
/20324,518,553,658,426,726,783,156,020,576,256 (2^108)17,592,186,044,416268,435,456YesLarge provider allocation (RIPE minimum for some)
/29633,825,300,114,114,700,748,351,602,688 (2^99)34,359,738,368524,288NoRIPE allocation to a provider (often)
/3279,228,162,514,264,337,593,543,950,336 (2^96)4,294,967,29665,536YesProvider allocation (RIPE default)
/364,951,760,157,141,521,099,596,496,896 (2^92)268,435,4564,096Yes
/40309,485,009,821,345,068,724,781,056 (2^88)16,777,216256Yes
/4419,342,813,113,834,066,795,298,816 (2^84)1,048,57616Yes
/481,208,925,819,614,629,174,706,176 (2^80)65,5361YesOne site or organisation (RIPE PI / assignment)
/5275,557,863,725,914,323,419,136 (2^76)4,096Yes
/564,722,366,482,869,645,213,696 (2^72)256YesSmall site or home (common provider assignment)
/60295,147,905,179,352,825,856 (2^68)16YesSome home broadband (16 LANs)
/6418,446,744,073,709,551,616 (2^64)1YesOne LAN or VLAN (needed for SLAAC)
/7272,057,594,037,927,936 (2^56)1/256 of a /64Yes
/80281,474,976,710,656 (2^48)1/65,536 of a /64Yes
/964,294,967,2961/4,294,967,296 of a /64YesEmbeds an IPv4 address (NAT64)
/11265,5361/281,474,976,710,656 of a /64Yes
/1202561/72,057,594,037,927,936 of a /64Yes
/124161/1,152,921,504,606,846,976 of a /64Yes
/12641/4,611,686,018,427,387,904 of a /64No
/12721/9,223,372,036,854,775,808 of a /64NoPoint-to-point link (RFC 6164)
/12811/18,446,744,073,709,551,616 of a /64YesOne host or loopback

Private and special ranges

IPv4

Special-purpose ranges
RangeNameWhat it is
255.255.255.255/32Limited broadcastEvery host on the local network
0.0.0.0/8This networkNot routed; 0.0.0.0 means "any address" in settings
10.0.0.0/8Private (RFC 1918)Office and home networks; not routed on the internet
100.64.0.0/10Shared address space (CGNAT)Used by providers behind carrier-grade NAT (RFC 6598)
127.0.0.0/8LoopbackThis computer
169.254.0.0/16Link-local (APIPA)Self-assigned when no DHCP server answers
172.16.0.0/12Private (RFC 1918)Office and home networks; not routed on the internet
192.0.0.0/24IETF protocol assignmentsSpecial uses such as DS-Lite
192.0.2.0/24Documentation (TEST-NET-1)For examples; never used on a network
192.88.99.0/246to4 relay (deprecated)Formerly anycast for 6to4
192.168.0.0/16Private (RFC 1918)Office and home networks; not routed on the internet
198.18.0.0/15BenchmarkingNetwork equipment testing (RFC 2544)
198.51.100.0/24Documentation (TEST-NET-2)For examples; never used on a network
203.0.113.0/24Documentation (TEST-NET-3)For examples; never used on a network
224.0.0.0/4MulticastOne-to-many traffic, such as IPTV and routing protocols
240.0.0.0/4ReservedFuture use; not usable on most systems

IPv6

Special-purpose ranges
RangeNameWhat it is
::/128UnspecifiedNo address; :: means "any address" in settings
::1/128LoopbackThis computer
::ffff:0:0/96IPv4-mappedAn IPv4 address written as IPv6
64:ff9b::/96NAT64IPv4 addresses reached through a NAT64 gateway
100::/64Discard onlyTraffic sent here is dropped (RFC 6666)
2001:db8::/32DocumentationFor examples; never used on a network
2001::/32TeredoIPv6 tunnelled over IPv4 UDP
2002::/166to4IPv6 tunnelled over IPv4 (largely retired)
3fff::/20DocumentationFor examples (RFC 9637)
fc00::/7Unique local (ULA)Private IPv6, like RFC 1918; usually fd00::/8
fe80::/10Link-localEvery IPv6 interface has one; not routed
ff00::/8MulticastOne-to-many traffic; replaces broadcast
2000::/3Global unicastPublic internet addresses

About this tool

A network is written as an address and a prefix length, such as 192.168.1.0/24: the first 24 bits name the network and the rest number the devices on it. The calculator works out where the network starts and ends, how many devices it holds, its subnet and wildcard masks, and the reverse DNS zone to ask your provider for.

It also splits a network into equal smaller ones (one per VLAN or site), turns a range of addresses into the fewest CIDR blocks for a firewall rule, and lists every IPv4 prefix length and the common IPv6 ones in reference tables.

Common questions

Why are two addresses lost in every IPv4 subnet?

The first address names the network and the last is the broadcast address, so a /24 has 256 addresses but 254 for devices. A /31 (a link between two routers) and a /32 (one host) are the exceptions.

What size of IPv6 network should a LAN use?

Always /64. Devices pick their own address within it (SLAAC), which needs the full 64 bits. A site usually gets a /48 or /56 from its provider, which holds 65,536 or 256 LANs.

What is a wildcard mask?

The subnet mask turned inside out: 255.255.255.0 becomes 0.0.0.255. Cisco access lists and OSPF use it to say which bits must match.

Which ranges can I use inside an office?

IPv4: 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16. IPv6: unique local addresses from fd00::/8, though most networks use the public prefix from their provider.