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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.

Network145.0.0.0/11
Usable hosts2,097,150
Subnet mask255.224.0.0
Addresses2,097,152
Network address
145.0.0.0
Broadcast address
145.31.255.255
First usable
145.0.0.1
Last usable
145.31.255.254
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
Public public
Old class
B (default /16)
As numbers
Hex 91000000 · Integer 2432696320 to 2434793471
Reverse DNS zones
0.145.in-addr.arpa
1.145.in-addr.arpa
2.145.in-addr.arpa
3.145.in-addr.arpa
4.145.in-addr.arpa
5.145.in-addr.arpa
6.145.in-addr.arpa
7.145.in-addr.arpa
8.145.in-addr.arpa
9.145.in-addr.arpa
10.145.in-addr.arpa
11.145.in-addr.arpa
12.145.in-addr.arpa
13.145.in-addr.arpa
14.145.in-addr.arpa
15.145.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
Address10010001.00000000.00000000.00000000145.0.0.0
Subnet mask11111111.11100000.00000000.00000000255.224.0.0
Network10010001.00000000.00000000.00000000145.0.0.0
Broadcast10010001.00011111.11111111.11111111145.31.255.255
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)

145.0.0.0/11 makes 1,024 subnets of /21; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1145.0.0.0/21145.0.0.1 to 145.0.7.254145.0.7.2552,046
2145.0.8.0/21145.0.8.1 to 145.0.15.254145.0.15.2552,046
3145.0.16.0/21145.0.16.1 to 145.0.23.254145.0.23.2552,046
4145.0.24.0/21145.0.24.1 to 145.0.31.254145.0.31.2552,046
5145.0.32.0/21145.0.32.1 to 145.0.39.254145.0.39.2552,046
6145.0.40.0/21145.0.40.1 to 145.0.47.254145.0.47.2552,046
7145.0.48.0/21145.0.48.1 to 145.0.55.254145.0.55.2552,046
8145.0.56.0/21145.0.56.1 to 145.0.63.254145.0.63.2552,046
9145.0.64.0/21145.0.64.1 to 145.0.71.254145.0.71.2552,046
10145.0.72.0/21145.0.72.1 to 145.0.79.254145.0.79.2552,046
11145.0.80.0/21145.0.80.1 to 145.0.87.254145.0.87.2552,046
12145.0.88.0/21145.0.88.1 to 145.0.95.254145.0.95.2552,046
13145.0.96.0/21145.0.96.1 to 145.0.103.254145.0.103.2552,046
14145.0.104.0/21145.0.104.1 to 145.0.111.254145.0.111.2552,046
15145.0.112.0/21145.0.112.1 to 145.0.119.254145.0.119.2552,046
16145.0.120.0/21145.0.120.1 to 145.0.127.254145.0.127.2552,046
17145.0.128.0/21145.0.128.1 to 145.0.135.254145.0.135.2552,046
18145.0.136.0/21145.0.136.1 to 145.0.143.254145.0.143.2552,046
19145.0.144.0/21145.0.144.1 to 145.0.151.254145.0.151.2552,046
20145.0.152.0/21145.0.152.1 to 145.0.159.254145.0.159.2552,046
21145.0.160.0/21145.0.160.1 to 145.0.167.254145.0.167.2552,046
22145.0.168.0/21145.0.168.1 to 145.0.175.254145.0.175.2552,046
23145.0.176.0/21145.0.176.1 to 145.0.183.254145.0.183.2552,046
24145.0.184.0/21145.0.184.1 to 145.0.191.254145.0.191.2552,046
25145.0.192.0/21145.0.192.1 to 145.0.199.254145.0.199.2552,046
26145.0.200.0/21145.0.200.1 to 145.0.207.254145.0.207.2552,046
27145.0.208.0/21145.0.208.1 to 145.0.215.254145.0.215.2552,046
28145.0.216.0/21145.0.216.1 to 145.0.223.254145.0.223.2552,046
29145.0.224.0/21145.0.224.1 to 145.0.231.254145.0.231.2552,046
30145.0.232.0/21145.0.232.1 to 145.0.239.254145.0.239.2552,046
31145.0.240.0/21145.0.240.1 to 145.0.247.254145.0.247.2552,046
32145.0.248.0/21145.0.248.1 to 145.0.255.254145.0.255.2552,046
33145.1.0.0/21145.1.0.1 to 145.1.7.254145.1.7.2552,046
34145.1.8.0/21145.1.8.1 to 145.1.15.254145.1.15.2552,046
35145.1.16.0/21145.1.16.1 to 145.1.23.254145.1.23.2552,046
36145.1.24.0/21145.1.24.1 to 145.1.31.254145.1.31.2552,046
37145.1.32.0/21145.1.32.1 to 145.1.39.254145.1.39.2552,046
38145.1.40.0/21145.1.40.1 to 145.1.47.254145.1.47.2552,046
39145.1.48.0/21145.1.48.1 to 145.1.55.254145.1.55.2552,046
40145.1.56.0/21145.1.56.1 to 145.1.63.254145.1.63.2552,046
41145.1.64.0/21145.1.64.1 to 145.1.71.254145.1.71.2552,046
42145.1.72.0/21145.1.72.1 to 145.1.79.254145.1.79.2552,046
43145.1.80.0/21145.1.80.1 to 145.1.87.254145.1.87.2552,046
44145.1.88.0/21145.1.88.1 to 145.1.95.254145.1.95.2552,046
45145.1.96.0/21145.1.96.1 to 145.1.103.254145.1.103.2552,046
46145.1.104.0/21145.1.104.1 to 145.1.111.254145.1.111.2552,046
47145.1.112.0/21145.1.112.1 to 145.1.119.254145.1.119.2552,046
48145.1.120.0/21145.1.120.1 to 145.1.127.254145.1.127.2552,046
49145.1.128.0/21145.1.128.1 to 145.1.135.254145.1.135.2552,046
50145.1.136.0/21145.1.136.1 to 145.1.143.254145.1.143.2552,046
51145.1.144.0/21145.1.144.1 to 145.1.151.254145.1.151.2552,046
52145.1.152.0/21145.1.152.1 to 145.1.159.254145.1.159.2552,046
53145.1.160.0/21145.1.160.1 to 145.1.167.254145.1.167.2552,046
54145.1.168.0/21145.1.168.1 to 145.1.175.254145.1.175.2552,046
55145.1.176.0/21145.1.176.1 to 145.1.183.254145.1.183.2552,046
56145.1.184.0/21145.1.184.1 to 145.1.191.254145.1.191.2552,046
57145.1.192.0/21145.1.192.1 to 145.1.199.254145.1.199.2552,046
58145.1.200.0/21145.1.200.1 to 145.1.207.254145.1.207.2552,046
59145.1.208.0/21145.1.208.1 to 145.1.215.254145.1.215.2552,046
60145.1.216.0/21145.1.216.1 to 145.1.223.254145.1.223.2552,046
61145.1.224.0/21145.1.224.1 to 145.1.231.254145.1.231.2552,046
62145.1.232.0/21145.1.232.1 to 145.1.239.254145.1.239.2552,046
63145.1.240.0/21145.1.240.1 to 145.1.247.254145.1.247.2552,046
64145.1.248.0/21145.1.248.1 to 145.1.255.254145.1.255.2552,046
65145.2.0.0/21145.2.0.1 to 145.2.7.254145.2.7.2552,046
66145.2.8.0/21145.2.8.1 to 145.2.15.254145.2.15.2552,046
67145.2.16.0/21145.2.16.1 to 145.2.23.254145.2.23.2552,046
68145.2.24.0/21145.2.24.1 to 145.2.31.254145.2.31.2552,046
69145.2.32.0/21145.2.32.1 to 145.2.39.254145.2.39.2552,046
70145.2.40.0/21145.2.40.1 to 145.2.47.254145.2.47.2552,046
71145.2.48.0/21145.2.48.1 to 145.2.55.254145.2.55.2552,046
72145.2.56.0/21145.2.56.1 to 145.2.63.254145.2.63.2552,046
73145.2.64.0/21145.2.64.1 to 145.2.71.254145.2.71.2552,046
74145.2.72.0/21145.2.72.1 to 145.2.79.254145.2.79.2552,046
75145.2.80.0/21145.2.80.1 to 145.2.87.254145.2.87.2552,046
76145.2.88.0/21145.2.88.1 to 145.2.95.254145.2.95.2552,046
77145.2.96.0/21145.2.96.1 to 145.2.103.254145.2.103.2552,046
78145.2.104.0/21145.2.104.1 to 145.2.111.254145.2.111.2552,046
79145.2.112.0/21145.2.112.1 to 145.2.119.254145.2.119.2552,046
80145.2.120.0/21145.2.120.1 to 145.2.127.254145.2.127.2552,046
81145.2.128.0/21145.2.128.1 to 145.2.135.254145.2.135.2552,046
82145.2.136.0/21145.2.136.1 to 145.2.143.254145.2.143.2552,046
83145.2.144.0/21145.2.144.1 to 145.2.151.254145.2.151.2552,046
84145.2.152.0/21145.2.152.1 to 145.2.159.254145.2.159.2552,046
85145.2.160.0/21145.2.160.1 to 145.2.167.254145.2.167.2552,046
86145.2.168.0/21145.2.168.1 to 145.2.175.254145.2.175.2552,046
87145.2.176.0/21145.2.176.1 to 145.2.183.254145.2.183.2552,046
88145.2.184.0/21145.2.184.1 to 145.2.191.254145.2.191.2552,046
89145.2.192.0/21145.2.192.1 to 145.2.199.254145.2.199.2552,046
90145.2.200.0/21145.2.200.1 to 145.2.207.254145.2.207.2552,046
91145.2.208.0/21145.2.208.1 to 145.2.215.254145.2.215.2552,046
92145.2.216.0/21145.2.216.1 to 145.2.223.254145.2.223.2552,046
93145.2.224.0/21145.2.224.1 to 145.2.231.254145.2.231.2552,046
94145.2.232.0/21145.2.232.1 to 145.2.239.254145.2.239.2552,046
95145.2.240.0/21145.2.240.1 to 145.2.247.254145.2.247.2552,046
96145.2.248.0/21145.2.248.1 to 145.2.255.254145.2.255.2552,046
97145.3.0.0/21145.3.0.1 to 145.3.7.254145.3.7.2552,046
98145.3.8.0/21145.3.8.1 to 145.3.15.254145.3.15.2552,046
99145.3.16.0/21145.3.16.1 to 145.3.23.254145.3.23.2552,046
100145.3.24.0/21145.3.24.1 to 145.3.31.254145.3.31.2552,046
101145.3.32.0/21145.3.32.1 to 145.3.39.254145.3.39.2552,046
102145.3.40.0/21145.3.40.1 to 145.3.47.254145.3.47.2552,046
103145.3.48.0/21145.3.48.1 to 145.3.55.254145.3.55.2552,046
104145.3.56.0/21145.3.56.1 to 145.3.63.254145.3.63.2552,046
105145.3.64.0/21145.3.64.1 to 145.3.71.254145.3.71.2552,046
106145.3.72.0/21145.3.72.1 to 145.3.79.254145.3.79.2552,046
107145.3.80.0/21145.3.80.1 to 145.3.87.254145.3.87.2552,046
108145.3.88.0/21145.3.88.1 to 145.3.95.254145.3.95.2552,046
109145.3.96.0/21145.3.96.1 to 145.3.103.254145.3.103.2552,046
110145.3.104.0/21145.3.104.1 to 145.3.111.254145.3.111.2552,046
111145.3.112.0/21145.3.112.1 to 145.3.119.254145.3.119.2552,046
112145.3.120.0/21145.3.120.1 to 145.3.127.254145.3.127.2552,046
113145.3.128.0/21145.3.128.1 to 145.3.135.254145.3.135.2552,046
114145.3.136.0/21145.3.136.1 to 145.3.143.254145.3.143.2552,046
115145.3.144.0/21145.3.144.1 to 145.3.151.254145.3.151.2552,046
116145.3.152.0/21145.3.152.1 to 145.3.159.254145.3.159.2552,046
117145.3.160.0/21145.3.160.1 to 145.3.167.254145.3.167.2552,046
118145.3.168.0/21145.3.168.1 to 145.3.175.254145.3.175.2552,046
119145.3.176.0/21145.3.176.1 to 145.3.183.254145.3.183.2552,046
120145.3.184.0/21145.3.184.1 to 145.3.191.254145.3.191.2552,046
121145.3.192.0/21145.3.192.1 to 145.3.199.254145.3.199.2552,046
122145.3.200.0/21145.3.200.1 to 145.3.207.254145.3.207.2552,046
123145.3.208.0/21145.3.208.1 to 145.3.215.254145.3.215.2552,046
124145.3.216.0/21145.3.216.1 to 145.3.223.254145.3.223.2552,046
125145.3.224.0/21145.3.224.1 to 145.3.231.254145.3.231.2552,046
126145.3.232.0/21145.3.232.1 to 145.3.239.254145.3.239.2552,046
127145.3.240.0/21145.3.240.1 to 145.3.247.254145.3.247.2552,046
128145.3.248.0/21145.3.248.1 to 145.3.255.254145.3.255.2552,046
129145.4.0.0/21145.4.0.1 to 145.4.7.254145.4.7.2552,046
130145.4.8.0/21145.4.8.1 to 145.4.15.254145.4.15.2552,046
131145.4.16.0/21145.4.16.1 to 145.4.23.254145.4.23.2552,046
132145.4.24.0/21145.4.24.1 to 145.4.31.254145.4.31.2552,046
133145.4.32.0/21145.4.32.1 to 145.4.39.254145.4.39.2552,046
134145.4.40.0/21145.4.40.1 to 145.4.47.254145.4.47.2552,046
135145.4.48.0/21145.4.48.1 to 145.4.55.254145.4.55.2552,046
136145.4.56.0/21145.4.56.1 to 145.4.63.254145.4.63.2552,046
137145.4.64.0/21145.4.64.1 to 145.4.71.254145.4.71.2552,046
138145.4.72.0/21145.4.72.1 to 145.4.79.254145.4.79.2552,046
139145.4.80.0/21145.4.80.1 to 145.4.87.254145.4.87.2552,046
140145.4.88.0/21145.4.88.1 to 145.4.95.254145.4.95.2552,046
141145.4.96.0/21145.4.96.1 to 145.4.103.254145.4.103.2552,046
142145.4.104.0/21145.4.104.1 to 145.4.111.254145.4.111.2552,046
143145.4.112.0/21145.4.112.1 to 145.4.119.254145.4.119.2552,046
144145.4.120.0/21145.4.120.1 to 145.4.127.254145.4.127.2552,046
145145.4.128.0/21145.4.128.1 to 145.4.135.254145.4.135.2552,046
146145.4.136.0/21145.4.136.1 to 145.4.143.254145.4.143.2552,046
147145.4.144.0/21145.4.144.1 to 145.4.151.254145.4.151.2552,046
148145.4.152.0/21145.4.152.1 to 145.4.159.254145.4.159.2552,046
149145.4.160.0/21145.4.160.1 to 145.4.167.254145.4.167.2552,046
150145.4.168.0/21145.4.168.1 to 145.4.175.254145.4.175.2552,046
151145.4.176.0/21145.4.176.1 to 145.4.183.254145.4.183.2552,046
152145.4.184.0/21145.4.184.1 to 145.4.191.254145.4.191.2552,046
153145.4.192.0/21145.4.192.1 to 145.4.199.254145.4.199.2552,046
154145.4.200.0/21145.4.200.1 to 145.4.207.254145.4.207.2552,046
155145.4.208.0/21145.4.208.1 to 145.4.215.254145.4.215.2552,046
156145.4.216.0/21145.4.216.1 to 145.4.223.254145.4.223.2552,046
157145.4.224.0/21145.4.224.1 to 145.4.231.254145.4.231.2552,046
158145.4.232.0/21145.4.232.1 to 145.4.239.254145.4.239.2552,046
159145.4.240.0/21145.4.240.1 to 145.4.247.254145.4.247.2552,046
160145.4.248.0/21145.4.248.1 to 145.4.255.254145.4.255.2552,046
161145.5.0.0/21145.5.0.1 to 145.5.7.254145.5.7.2552,046
162145.5.8.0/21145.5.8.1 to 145.5.15.254145.5.15.2552,046
163145.5.16.0/21145.5.16.1 to 145.5.23.254145.5.23.2552,046
164145.5.24.0/21145.5.24.1 to 145.5.31.254145.5.31.2552,046
165145.5.32.0/21145.5.32.1 to 145.5.39.254145.5.39.2552,046
166145.5.40.0/21145.5.40.1 to 145.5.47.254145.5.47.2552,046
167145.5.48.0/21145.5.48.1 to 145.5.55.254145.5.55.2552,046
168145.5.56.0/21145.5.56.1 to 145.5.63.254145.5.63.2552,046
169145.5.64.0/21145.5.64.1 to 145.5.71.254145.5.71.2552,046
170145.5.72.0/21145.5.72.1 to 145.5.79.254145.5.79.2552,046
171145.5.80.0/21145.5.80.1 to 145.5.87.254145.5.87.2552,046
172145.5.88.0/21145.5.88.1 to 145.5.95.254145.5.95.2552,046
173145.5.96.0/21145.5.96.1 to 145.5.103.254145.5.103.2552,046
174145.5.104.0/21145.5.104.1 to 145.5.111.254145.5.111.2552,046
175145.5.112.0/21145.5.112.1 to 145.5.119.254145.5.119.2552,046
176145.5.120.0/21145.5.120.1 to 145.5.127.254145.5.127.2552,046
177145.5.128.0/21145.5.128.1 to 145.5.135.254145.5.135.2552,046
178145.5.136.0/21145.5.136.1 to 145.5.143.254145.5.143.2552,046
179145.5.144.0/21145.5.144.1 to 145.5.151.254145.5.151.2552,046
180145.5.152.0/21145.5.152.1 to 145.5.159.254145.5.159.2552,046
181145.5.160.0/21145.5.160.1 to 145.5.167.254145.5.167.2552,046
182145.5.168.0/21145.5.168.1 to 145.5.175.254145.5.175.2552,046
183145.5.176.0/21145.5.176.1 to 145.5.183.254145.5.183.2552,046
184145.5.184.0/21145.5.184.1 to 145.5.191.254145.5.191.2552,046
185145.5.192.0/21145.5.192.1 to 145.5.199.254145.5.199.2552,046
186145.5.200.0/21145.5.200.1 to 145.5.207.254145.5.207.2552,046
187145.5.208.0/21145.5.208.1 to 145.5.215.254145.5.215.2552,046
188145.5.216.0/21145.5.216.1 to 145.5.223.254145.5.223.2552,046
189145.5.224.0/21145.5.224.1 to 145.5.231.254145.5.231.2552,046
190145.5.232.0/21145.5.232.1 to 145.5.239.254145.5.239.2552,046
191145.5.240.0/21145.5.240.1 to 145.5.247.254145.5.247.2552,046
192145.5.248.0/21145.5.248.1 to 145.5.255.254145.5.255.2552,046
193145.6.0.0/21145.6.0.1 to 145.6.7.254145.6.7.2552,046
194145.6.8.0/21145.6.8.1 to 145.6.15.254145.6.15.2552,046
195145.6.16.0/21145.6.16.1 to 145.6.23.254145.6.23.2552,046
196145.6.24.0/21145.6.24.1 to 145.6.31.254145.6.31.2552,046
197145.6.32.0/21145.6.32.1 to 145.6.39.254145.6.39.2552,046
198145.6.40.0/21145.6.40.1 to 145.6.47.254145.6.47.2552,046
199145.6.48.0/21145.6.48.1 to 145.6.55.254145.6.55.2552,046
200145.6.56.0/21145.6.56.1 to 145.6.63.254145.6.63.2552,046
201145.6.64.0/21145.6.64.1 to 145.6.71.254145.6.71.2552,046
202145.6.72.0/21145.6.72.1 to 145.6.79.254145.6.79.2552,046
203145.6.80.0/21145.6.80.1 to 145.6.87.254145.6.87.2552,046
204145.6.88.0/21145.6.88.1 to 145.6.95.254145.6.95.2552,046
205145.6.96.0/21145.6.96.1 to 145.6.103.254145.6.103.2552,046
206145.6.104.0/21145.6.104.1 to 145.6.111.254145.6.111.2552,046
207145.6.112.0/21145.6.112.1 to 145.6.119.254145.6.119.2552,046
208145.6.120.0/21145.6.120.1 to 145.6.127.254145.6.127.2552,046
209145.6.128.0/21145.6.128.1 to 145.6.135.254145.6.135.2552,046
210145.6.136.0/21145.6.136.1 to 145.6.143.254145.6.143.2552,046
211145.6.144.0/21145.6.144.1 to 145.6.151.254145.6.151.2552,046
212145.6.152.0/21145.6.152.1 to 145.6.159.254145.6.159.2552,046
213145.6.160.0/21145.6.160.1 to 145.6.167.254145.6.167.2552,046
214145.6.168.0/21145.6.168.1 to 145.6.175.254145.6.175.2552,046
215145.6.176.0/21145.6.176.1 to 145.6.183.254145.6.183.2552,046
216145.6.184.0/21145.6.184.1 to 145.6.191.254145.6.191.2552,046
217145.6.192.0/21145.6.192.1 to 145.6.199.254145.6.199.2552,046
218145.6.200.0/21145.6.200.1 to 145.6.207.254145.6.207.2552,046
219145.6.208.0/21145.6.208.1 to 145.6.215.254145.6.215.2552,046
220145.6.216.0/21145.6.216.1 to 145.6.223.254145.6.223.2552,046
221145.6.224.0/21145.6.224.1 to 145.6.231.254145.6.231.2552,046
222145.6.232.0/21145.6.232.1 to 145.6.239.254145.6.239.2552,046
223145.6.240.0/21145.6.240.1 to 145.6.247.254145.6.247.2552,046
224145.6.248.0/21145.6.248.1 to 145.6.255.254145.6.255.2552,046
225145.7.0.0/21145.7.0.1 to 145.7.7.254145.7.7.2552,046
226145.7.8.0/21145.7.8.1 to 145.7.15.254145.7.15.2552,046
227145.7.16.0/21145.7.16.1 to 145.7.23.254145.7.23.2552,046
228145.7.24.0/21145.7.24.1 to 145.7.31.254145.7.31.2552,046
229145.7.32.0/21145.7.32.1 to 145.7.39.254145.7.39.2552,046
230145.7.40.0/21145.7.40.1 to 145.7.47.254145.7.47.2552,046
231145.7.48.0/21145.7.48.1 to 145.7.55.254145.7.55.2552,046
232145.7.56.0/21145.7.56.1 to 145.7.63.254145.7.63.2552,046
233145.7.64.0/21145.7.64.1 to 145.7.71.254145.7.71.2552,046
234145.7.72.0/21145.7.72.1 to 145.7.79.254145.7.79.2552,046
235145.7.80.0/21145.7.80.1 to 145.7.87.254145.7.87.2552,046
236145.7.88.0/21145.7.88.1 to 145.7.95.254145.7.95.2552,046
237145.7.96.0/21145.7.96.1 to 145.7.103.254145.7.103.2552,046
238145.7.104.0/21145.7.104.1 to 145.7.111.254145.7.111.2552,046
239145.7.112.0/21145.7.112.1 to 145.7.119.254145.7.119.2552,046
240145.7.120.0/21145.7.120.1 to 145.7.127.254145.7.127.2552,046
241145.7.128.0/21145.7.128.1 to 145.7.135.254145.7.135.2552,046
242145.7.136.0/21145.7.136.1 to 145.7.143.254145.7.143.2552,046
243145.7.144.0/21145.7.144.1 to 145.7.151.254145.7.151.2552,046
244145.7.152.0/21145.7.152.1 to 145.7.159.254145.7.159.2552,046
245145.7.160.0/21145.7.160.1 to 145.7.167.254145.7.167.2552,046
246145.7.168.0/21145.7.168.1 to 145.7.175.254145.7.175.2552,046
247145.7.176.0/21145.7.176.1 to 145.7.183.254145.7.183.2552,046
248145.7.184.0/21145.7.184.1 to 145.7.191.254145.7.191.2552,046
249145.7.192.0/21145.7.192.1 to 145.7.199.254145.7.199.2552,046
250145.7.200.0/21145.7.200.1 to 145.7.207.254145.7.207.2552,046
251145.7.208.0/21145.7.208.1 to 145.7.215.254145.7.215.2552,046
252145.7.216.0/21145.7.216.1 to 145.7.223.254145.7.223.2552,046
253145.7.224.0/21145.7.224.1 to 145.7.231.254145.7.231.2552,046
254145.7.232.0/21145.7.232.1 to 145.7.239.254145.7.239.2552,046
255145.7.240.0/21145.7.240.1 to 145.7.247.254145.7.247.2552,046
256145.7.248.0/21145.7.248.1 to 145.7.255.254145.7.255.2552,046

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.