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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.

Network145.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
145.0.0.0
Broadcast address
145.255.255.255
First usable
145.0.0.1
Last usable
145.255.255.254
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
Public public
Old class
B (default /16)
As numbers
Hex 91000000 · Integer 2432696320 to 2449473535
Reverse DNS zone
145.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10010001..00000000.00000000.00000000145.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network10010001..00000000.00000000.00000000145.0.0.0
Broadcast10010001..11111111.11111111.11111111145.255.255.255
Split into smaller subnets/20
/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)

145.0.0.0/8 makes 4,096 subnets of /20; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1145.0.0.0/20145.0.0.1 to 145.0.15.254145.0.15.2554,094
2145.0.16.0/20145.0.16.1 to 145.0.31.254145.0.31.2554,094
3145.0.32.0/20145.0.32.1 to 145.0.47.254145.0.47.2554,094
4145.0.48.0/20145.0.48.1 to 145.0.63.254145.0.63.2554,094
5145.0.64.0/20145.0.64.1 to 145.0.79.254145.0.79.2554,094
6145.0.80.0/20145.0.80.1 to 145.0.95.254145.0.95.2554,094
7145.0.96.0/20145.0.96.1 to 145.0.111.254145.0.111.2554,094
8145.0.112.0/20145.0.112.1 to 145.0.127.254145.0.127.2554,094
9145.0.128.0/20145.0.128.1 to 145.0.143.254145.0.143.2554,094
10145.0.144.0/20145.0.144.1 to 145.0.159.254145.0.159.2554,094
11145.0.160.0/20145.0.160.1 to 145.0.175.254145.0.175.2554,094
12145.0.176.0/20145.0.176.1 to 145.0.191.254145.0.191.2554,094
13145.0.192.0/20145.0.192.1 to 145.0.207.254145.0.207.2554,094
14145.0.208.0/20145.0.208.1 to 145.0.223.254145.0.223.2554,094
15145.0.224.0/20145.0.224.1 to 145.0.239.254145.0.239.2554,094
16145.0.240.0/20145.0.240.1 to 145.0.255.254145.0.255.2554,094
17145.1.0.0/20145.1.0.1 to 145.1.15.254145.1.15.2554,094
18145.1.16.0/20145.1.16.1 to 145.1.31.254145.1.31.2554,094
19145.1.32.0/20145.1.32.1 to 145.1.47.254145.1.47.2554,094
20145.1.48.0/20145.1.48.1 to 145.1.63.254145.1.63.2554,094
21145.1.64.0/20145.1.64.1 to 145.1.79.254145.1.79.2554,094
22145.1.80.0/20145.1.80.1 to 145.1.95.254145.1.95.2554,094
23145.1.96.0/20145.1.96.1 to 145.1.111.254145.1.111.2554,094
24145.1.112.0/20145.1.112.1 to 145.1.127.254145.1.127.2554,094
25145.1.128.0/20145.1.128.1 to 145.1.143.254145.1.143.2554,094
26145.1.144.0/20145.1.144.1 to 145.1.159.254145.1.159.2554,094
27145.1.160.0/20145.1.160.1 to 145.1.175.254145.1.175.2554,094
28145.1.176.0/20145.1.176.1 to 145.1.191.254145.1.191.2554,094
29145.1.192.0/20145.1.192.1 to 145.1.207.254145.1.207.2554,094
30145.1.208.0/20145.1.208.1 to 145.1.223.254145.1.223.2554,094
31145.1.224.0/20145.1.224.1 to 145.1.239.254145.1.239.2554,094
32145.1.240.0/20145.1.240.1 to 145.1.255.254145.1.255.2554,094
33145.2.0.0/20145.2.0.1 to 145.2.15.254145.2.15.2554,094
34145.2.16.0/20145.2.16.1 to 145.2.31.254145.2.31.2554,094
35145.2.32.0/20145.2.32.1 to 145.2.47.254145.2.47.2554,094
36145.2.48.0/20145.2.48.1 to 145.2.63.254145.2.63.2554,094
37145.2.64.0/20145.2.64.1 to 145.2.79.254145.2.79.2554,094
38145.2.80.0/20145.2.80.1 to 145.2.95.254145.2.95.2554,094
39145.2.96.0/20145.2.96.1 to 145.2.111.254145.2.111.2554,094
40145.2.112.0/20145.2.112.1 to 145.2.127.254145.2.127.2554,094
41145.2.128.0/20145.2.128.1 to 145.2.143.254145.2.143.2554,094
42145.2.144.0/20145.2.144.1 to 145.2.159.254145.2.159.2554,094
43145.2.160.0/20145.2.160.1 to 145.2.175.254145.2.175.2554,094
44145.2.176.0/20145.2.176.1 to 145.2.191.254145.2.191.2554,094
45145.2.192.0/20145.2.192.1 to 145.2.207.254145.2.207.2554,094
46145.2.208.0/20145.2.208.1 to 145.2.223.254145.2.223.2554,094
47145.2.224.0/20145.2.224.1 to 145.2.239.254145.2.239.2554,094
48145.2.240.0/20145.2.240.1 to 145.2.255.254145.2.255.2554,094
49145.3.0.0/20145.3.0.1 to 145.3.15.254145.3.15.2554,094
50145.3.16.0/20145.3.16.1 to 145.3.31.254145.3.31.2554,094
51145.3.32.0/20145.3.32.1 to 145.3.47.254145.3.47.2554,094
52145.3.48.0/20145.3.48.1 to 145.3.63.254145.3.63.2554,094
53145.3.64.0/20145.3.64.1 to 145.3.79.254145.3.79.2554,094
54145.3.80.0/20145.3.80.1 to 145.3.95.254145.3.95.2554,094
55145.3.96.0/20145.3.96.1 to 145.3.111.254145.3.111.2554,094
56145.3.112.0/20145.3.112.1 to 145.3.127.254145.3.127.2554,094
57145.3.128.0/20145.3.128.1 to 145.3.143.254145.3.143.2554,094
58145.3.144.0/20145.3.144.1 to 145.3.159.254145.3.159.2554,094
59145.3.160.0/20145.3.160.1 to 145.3.175.254145.3.175.2554,094
60145.3.176.0/20145.3.176.1 to 145.3.191.254145.3.191.2554,094
61145.3.192.0/20145.3.192.1 to 145.3.207.254145.3.207.2554,094
62145.3.208.0/20145.3.208.1 to 145.3.223.254145.3.223.2554,094
63145.3.224.0/20145.3.224.1 to 145.3.239.254145.3.239.2554,094
64145.3.240.0/20145.3.240.1 to 145.3.255.254145.3.255.2554,094
65145.4.0.0/20145.4.0.1 to 145.4.15.254145.4.15.2554,094
66145.4.16.0/20145.4.16.1 to 145.4.31.254145.4.31.2554,094
67145.4.32.0/20145.4.32.1 to 145.4.47.254145.4.47.2554,094
68145.4.48.0/20145.4.48.1 to 145.4.63.254145.4.63.2554,094
69145.4.64.0/20145.4.64.1 to 145.4.79.254145.4.79.2554,094
70145.4.80.0/20145.4.80.1 to 145.4.95.254145.4.95.2554,094
71145.4.96.0/20145.4.96.1 to 145.4.111.254145.4.111.2554,094
72145.4.112.0/20145.4.112.1 to 145.4.127.254145.4.127.2554,094
73145.4.128.0/20145.4.128.1 to 145.4.143.254145.4.143.2554,094
74145.4.144.0/20145.4.144.1 to 145.4.159.254145.4.159.2554,094
75145.4.160.0/20145.4.160.1 to 145.4.175.254145.4.175.2554,094
76145.4.176.0/20145.4.176.1 to 145.4.191.254145.4.191.2554,094
77145.4.192.0/20145.4.192.1 to 145.4.207.254145.4.207.2554,094
78145.4.208.0/20145.4.208.1 to 145.4.223.254145.4.223.2554,094
79145.4.224.0/20145.4.224.1 to 145.4.239.254145.4.239.2554,094
80145.4.240.0/20145.4.240.1 to 145.4.255.254145.4.255.2554,094
81145.5.0.0/20145.5.0.1 to 145.5.15.254145.5.15.2554,094
82145.5.16.0/20145.5.16.1 to 145.5.31.254145.5.31.2554,094
83145.5.32.0/20145.5.32.1 to 145.5.47.254145.5.47.2554,094
84145.5.48.0/20145.5.48.1 to 145.5.63.254145.5.63.2554,094
85145.5.64.0/20145.5.64.1 to 145.5.79.254145.5.79.2554,094
86145.5.80.0/20145.5.80.1 to 145.5.95.254145.5.95.2554,094
87145.5.96.0/20145.5.96.1 to 145.5.111.254145.5.111.2554,094
88145.5.112.0/20145.5.112.1 to 145.5.127.254145.5.127.2554,094
89145.5.128.0/20145.5.128.1 to 145.5.143.254145.5.143.2554,094
90145.5.144.0/20145.5.144.1 to 145.5.159.254145.5.159.2554,094
91145.5.160.0/20145.5.160.1 to 145.5.175.254145.5.175.2554,094
92145.5.176.0/20145.5.176.1 to 145.5.191.254145.5.191.2554,094
93145.5.192.0/20145.5.192.1 to 145.5.207.254145.5.207.2554,094
94145.5.208.0/20145.5.208.1 to 145.5.223.254145.5.223.2554,094
95145.5.224.0/20145.5.224.1 to 145.5.239.254145.5.239.2554,094
96145.5.240.0/20145.5.240.1 to 145.5.255.254145.5.255.2554,094
97145.6.0.0/20145.6.0.1 to 145.6.15.254145.6.15.2554,094
98145.6.16.0/20145.6.16.1 to 145.6.31.254145.6.31.2554,094
99145.6.32.0/20145.6.32.1 to 145.6.47.254145.6.47.2554,094
100145.6.48.0/20145.6.48.1 to 145.6.63.254145.6.63.2554,094
101145.6.64.0/20145.6.64.1 to 145.6.79.254145.6.79.2554,094
102145.6.80.0/20145.6.80.1 to 145.6.95.254145.6.95.2554,094
103145.6.96.0/20145.6.96.1 to 145.6.111.254145.6.111.2554,094
104145.6.112.0/20145.6.112.1 to 145.6.127.254145.6.127.2554,094
105145.6.128.0/20145.6.128.1 to 145.6.143.254145.6.143.2554,094
106145.6.144.0/20145.6.144.1 to 145.6.159.254145.6.159.2554,094
107145.6.160.0/20145.6.160.1 to 145.6.175.254145.6.175.2554,094
108145.6.176.0/20145.6.176.1 to 145.6.191.254145.6.191.2554,094
109145.6.192.0/20145.6.192.1 to 145.6.207.254145.6.207.2554,094
110145.6.208.0/20145.6.208.1 to 145.6.223.254145.6.223.2554,094
111145.6.224.0/20145.6.224.1 to 145.6.239.254145.6.239.2554,094
112145.6.240.0/20145.6.240.1 to 145.6.255.254145.6.255.2554,094
113145.7.0.0/20145.7.0.1 to 145.7.15.254145.7.15.2554,094
114145.7.16.0/20145.7.16.1 to 145.7.31.254145.7.31.2554,094
115145.7.32.0/20145.7.32.1 to 145.7.47.254145.7.47.2554,094
116145.7.48.0/20145.7.48.1 to 145.7.63.254145.7.63.2554,094
117145.7.64.0/20145.7.64.1 to 145.7.79.254145.7.79.2554,094
118145.7.80.0/20145.7.80.1 to 145.7.95.254145.7.95.2554,094
119145.7.96.0/20145.7.96.1 to 145.7.111.254145.7.111.2554,094
120145.7.112.0/20145.7.112.1 to 145.7.127.254145.7.127.2554,094
121145.7.128.0/20145.7.128.1 to 145.7.143.254145.7.143.2554,094
122145.7.144.0/20145.7.144.1 to 145.7.159.254145.7.159.2554,094
123145.7.160.0/20145.7.160.1 to 145.7.175.254145.7.175.2554,094
124145.7.176.0/20145.7.176.1 to 145.7.191.254145.7.191.2554,094
125145.7.192.0/20145.7.192.1 to 145.7.207.254145.7.207.2554,094
126145.7.208.0/20145.7.208.1 to 145.7.223.254145.7.223.2554,094
127145.7.224.0/20145.7.224.1 to 145.7.239.254145.7.239.2554,094
128145.7.240.0/20145.7.240.1 to 145.7.255.254145.7.255.2554,094
129145.8.0.0/20145.8.0.1 to 145.8.15.254145.8.15.2554,094
130145.8.16.0/20145.8.16.1 to 145.8.31.254145.8.31.2554,094
131145.8.32.0/20145.8.32.1 to 145.8.47.254145.8.47.2554,094
132145.8.48.0/20145.8.48.1 to 145.8.63.254145.8.63.2554,094
133145.8.64.0/20145.8.64.1 to 145.8.79.254145.8.79.2554,094
134145.8.80.0/20145.8.80.1 to 145.8.95.254145.8.95.2554,094
135145.8.96.0/20145.8.96.1 to 145.8.111.254145.8.111.2554,094
136145.8.112.0/20145.8.112.1 to 145.8.127.254145.8.127.2554,094
137145.8.128.0/20145.8.128.1 to 145.8.143.254145.8.143.2554,094
138145.8.144.0/20145.8.144.1 to 145.8.159.254145.8.159.2554,094
139145.8.160.0/20145.8.160.1 to 145.8.175.254145.8.175.2554,094
140145.8.176.0/20145.8.176.1 to 145.8.191.254145.8.191.2554,094
141145.8.192.0/20145.8.192.1 to 145.8.207.254145.8.207.2554,094
142145.8.208.0/20145.8.208.1 to 145.8.223.254145.8.223.2554,094
143145.8.224.0/20145.8.224.1 to 145.8.239.254145.8.239.2554,094
144145.8.240.0/20145.8.240.1 to 145.8.255.254145.8.255.2554,094
145145.9.0.0/20145.9.0.1 to 145.9.15.254145.9.15.2554,094
146145.9.16.0/20145.9.16.1 to 145.9.31.254145.9.31.2554,094
147145.9.32.0/20145.9.32.1 to 145.9.47.254145.9.47.2554,094
148145.9.48.0/20145.9.48.1 to 145.9.63.254145.9.63.2554,094
149145.9.64.0/20145.9.64.1 to 145.9.79.254145.9.79.2554,094
150145.9.80.0/20145.9.80.1 to 145.9.95.254145.9.95.2554,094
151145.9.96.0/20145.9.96.1 to 145.9.111.254145.9.111.2554,094
152145.9.112.0/20145.9.112.1 to 145.9.127.254145.9.127.2554,094
153145.9.128.0/20145.9.128.1 to 145.9.143.254145.9.143.2554,094
154145.9.144.0/20145.9.144.1 to 145.9.159.254145.9.159.2554,094
155145.9.160.0/20145.9.160.1 to 145.9.175.254145.9.175.2554,094
156145.9.176.0/20145.9.176.1 to 145.9.191.254145.9.191.2554,094
157145.9.192.0/20145.9.192.1 to 145.9.207.254145.9.207.2554,094
158145.9.208.0/20145.9.208.1 to 145.9.223.254145.9.223.2554,094
159145.9.224.0/20145.9.224.1 to 145.9.239.254145.9.239.2554,094
160145.9.240.0/20145.9.240.1 to 145.9.255.254145.9.255.2554,094
161145.10.0.0/20145.10.0.1 to 145.10.15.254145.10.15.2554,094
162145.10.16.0/20145.10.16.1 to 145.10.31.254145.10.31.2554,094
163145.10.32.0/20145.10.32.1 to 145.10.47.254145.10.47.2554,094
164145.10.48.0/20145.10.48.1 to 145.10.63.254145.10.63.2554,094
165145.10.64.0/20145.10.64.1 to 145.10.79.254145.10.79.2554,094
166145.10.80.0/20145.10.80.1 to 145.10.95.254145.10.95.2554,094
167145.10.96.0/20145.10.96.1 to 145.10.111.254145.10.111.2554,094
168145.10.112.0/20145.10.112.1 to 145.10.127.254145.10.127.2554,094
169145.10.128.0/20145.10.128.1 to 145.10.143.254145.10.143.2554,094
170145.10.144.0/20145.10.144.1 to 145.10.159.254145.10.159.2554,094
171145.10.160.0/20145.10.160.1 to 145.10.175.254145.10.175.2554,094
172145.10.176.0/20145.10.176.1 to 145.10.191.254145.10.191.2554,094
173145.10.192.0/20145.10.192.1 to 145.10.207.254145.10.207.2554,094
174145.10.208.0/20145.10.208.1 to 145.10.223.254145.10.223.2554,094
175145.10.224.0/20145.10.224.1 to 145.10.239.254145.10.239.2554,094
176145.10.240.0/20145.10.240.1 to 145.10.255.254145.10.255.2554,094
177145.11.0.0/20145.11.0.1 to 145.11.15.254145.11.15.2554,094
178145.11.16.0/20145.11.16.1 to 145.11.31.254145.11.31.2554,094
179145.11.32.0/20145.11.32.1 to 145.11.47.254145.11.47.2554,094
180145.11.48.0/20145.11.48.1 to 145.11.63.254145.11.63.2554,094
181145.11.64.0/20145.11.64.1 to 145.11.79.254145.11.79.2554,094
182145.11.80.0/20145.11.80.1 to 145.11.95.254145.11.95.2554,094
183145.11.96.0/20145.11.96.1 to 145.11.111.254145.11.111.2554,094
184145.11.112.0/20145.11.112.1 to 145.11.127.254145.11.127.2554,094
185145.11.128.0/20145.11.128.1 to 145.11.143.254145.11.143.2554,094
186145.11.144.0/20145.11.144.1 to 145.11.159.254145.11.159.2554,094
187145.11.160.0/20145.11.160.1 to 145.11.175.254145.11.175.2554,094
188145.11.176.0/20145.11.176.1 to 145.11.191.254145.11.191.2554,094
189145.11.192.0/20145.11.192.1 to 145.11.207.254145.11.207.2554,094
190145.11.208.0/20145.11.208.1 to 145.11.223.254145.11.223.2554,094
191145.11.224.0/20145.11.224.1 to 145.11.239.254145.11.239.2554,094
192145.11.240.0/20145.11.240.1 to 145.11.255.254145.11.255.2554,094
193145.12.0.0/20145.12.0.1 to 145.12.15.254145.12.15.2554,094
194145.12.16.0/20145.12.16.1 to 145.12.31.254145.12.31.2554,094
195145.12.32.0/20145.12.32.1 to 145.12.47.254145.12.47.2554,094
196145.12.48.0/20145.12.48.1 to 145.12.63.254145.12.63.2554,094
197145.12.64.0/20145.12.64.1 to 145.12.79.254145.12.79.2554,094
198145.12.80.0/20145.12.80.1 to 145.12.95.254145.12.95.2554,094
199145.12.96.0/20145.12.96.1 to 145.12.111.254145.12.111.2554,094
200145.12.112.0/20145.12.112.1 to 145.12.127.254145.12.127.2554,094
201145.12.128.0/20145.12.128.1 to 145.12.143.254145.12.143.2554,094
202145.12.144.0/20145.12.144.1 to 145.12.159.254145.12.159.2554,094
203145.12.160.0/20145.12.160.1 to 145.12.175.254145.12.175.2554,094
204145.12.176.0/20145.12.176.1 to 145.12.191.254145.12.191.2554,094
205145.12.192.0/20145.12.192.1 to 145.12.207.254145.12.207.2554,094
206145.12.208.0/20145.12.208.1 to 145.12.223.254145.12.223.2554,094
207145.12.224.0/20145.12.224.1 to 145.12.239.254145.12.239.2554,094
208145.12.240.0/20145.12.240.1 to 145.12.255.254145.12.255.2554,094
209145.13.0.0/20145.13.0.1 to 145.13.15.254145.13.15.2554,094
210145.13.16.0/20145.13.16.1 to 145.13.31.254145.13.31.2554,094
211145.13.32.0/20145.13.32.1 to 145.13.47.254145.13.47.2554,094
212145.13.48.0/20145.13.48.1 to 145.13.63.254145.13.63.2554,094
213145.13.64.0/20145.13.64.1 to 145.13.79.254145.13.79.2554,094
214145.13.80.0/20145.13.80.1 to 145.13.95.254145.13.95.2554,094
215145.13.96.0/20145.13.96.1 to 145.13.111.254145.13.111.2554,094
216145.13.112.0/20145.13.112.1 to 145.13.127.254145.13.127.2554,094
217145.13.128.0/20145.13.128.1 to 145.13.143.254145.13.143.2554,094
218145.13.144.0/20145.13.144.1 to 145.13.159.254145.13.159.2554,094
219145.13.160.0/20145.13.160.1 to 145.13.175.254145.13.175.2554,094
220145.13.176.0/20145.13.176.1 to 145.13.191.254145.13.191.2554,094
221145.13.192.0/20145.13.192.1 to 145.13.207.254145.13.207.2554,094
222145.13.208.0/20145.13.208.1 to 145.13.223.254145.13.223.2554,094
223145.13.224.0/20145.13.224.1 to 145.13.239.254145.13.239.2554,094
224145.13.240.0/20145.13.240.1 to 145.13.255.254145.13.255.2554,094
225145.14.0.0/20145.14.0.1 to 145.14.15.254145.14.15.2554,094
226145.14.16.0/20145.14.16.1 to 145.14.31.254145.14.31.2554,094
227145.14.32.0/20145.14.32.1 to 145.14.47.254145.14.47.2554,094
228145.14.48.0/20145.14.48.1 to 145.14.63.254145.14.63.2554,094
229145.14.64.0/20145.14.64.1 to 145.14.79.254145.14.79.2554,094
230145.14.80.0/20145.14.80.1 to 145.14.95.254145.14.95.2554,094
231145.14.96.0/20145.14.96.1 to 145.14.111.254145.14.111.2554,094
232145.14.112.0/20145.14.112.1 to 145.14.127.254145.14.127.2554,094
233145.14.128.0/20145.14.128.1 to 145.14.143.254145.14.143.2554,094
234145.14.144.0/20145.14.144.1 to 145.14.159.254145.14.159.2554,094
235145.14.160.0/20145.14.160.1 to 145.14.175.254145.14.175.2554,094
236145.14.176.0/20145.14.176.1 to 145.14.191.254145.14.191.2554,094
237145.14.192.0/20145.14.192.1 to 145.14.207.254145.14.207.2554,094
238145.14.208.0/20145.14.208.1 to 145.14.223.254145.14.223.2554,094
239145.14.224.0/20145.14.224.1 to 145.14.239.254145.14.239.2554,094
240145.14.240.0/20145.14.240.1 to 145.14.255.254145.14.255.2554,094
241145.15.0.0/20145.15.0.1 to 145.15.15.254145.15.15.2554,094
242145.15.16.0/20145.15.16.1 to 145.15.31.254145.15.31.2554,094
243145.15.32.0/20145.15.32.1 to 145.15.47.254145.15.47.2554,094
244145.15.48.0/20145.15.48.1 to 145.15.63.254145.15.63.2554,094
245145.15.64.0/20145.15.64.1 to 145.15.79.254145.15.79.2554,094
246145.15.80.0/20145.15.80.1 to 145.15.95.254145.15.95.2554,094
247145.15.96.0/20145.15.96.1 to 145.15.111.254145.15.111.2554,094
248145.15.112.0/20145.15.112.1 to 145.15.127.254145.15.127.2554,094
249145.15.128.0/20145.15.128.1 to 145.15.143.254145.15.143.2554,094
250145.15.144.0/20145.15.144.1 to 145.15.159.254145.15.159.2554,094
251145.15.160.0/20145.15.160.1 to 145.15.175.254145.15.175.2554,094
252145.15.176.0/20145.15.176.1 to 145.15.191.254145.15.191.2554,094
253145.15.192.0/20145.15.192.1 to 145.15.207.254145.15.207.2554,094
254145.15.208.0/20145.15.208.1 to 145.15.223.254145.15.223.2554,094
255145.15.224.0/20145.15.224.1 to 145.15.239.254145.15.239.2554,094
256145.15.240.0/20145.15.240.1 to 145.15.255.254145.15.255.2554,094

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.