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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/18
/9 (2)/10 (4)/11 (8)/12 (16)/13 (32)/14 (64)/15 (128)/16 (256)/17 (512)/18 (1,024)/19 (2,048)/20 (4,096)

145.0.0.0/8 makes 1,024 subnets of /18; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1145.0.0.0/18145.0.0.1 to 145.0.63.254145.0.63.25516,382
2145.0.64.0/18145.0.64.1 to 145.0.127.254145.0.127.25516,382
3145.0.128.0/18145.0.128.1 to 145.0.191.254145.0.191.25516,382
4145.0.192.0/18145.0.192.1 to 145.0.255.254145.0.255.25516,382
5145.1.0.0/18145.1.0.1 to 145.1.63.254145.1.63.25516,382
6145.1.64.0/18145.1.64.1 to 145.1.127.254145.1.127.25516,382
7145.1.128.0/18145.1.128.1 to 145.1.191.254145.1.191.25516,382
8145.1.192.0/18145.1.192.1 to 145.1.255.254145.1.255.25516,382
9145.2.0.0/18145.2.0.1 to 145.2.63.254145.2.63.25516,382
10145.2.64.0/18145.2.64.1 to 145.2.127.254145.2.127.25516,382
11145.2.128.0/18145.2.128.1 to 145.2.191.254145.2.191.25516,382
12145.2.192.0/18145.2.192.1 to 145.2.255.254145.2.255.25516,382
13145.3.0.0/18145.3.0.1 to 145.3.63.254145.3.63.25516,382
14145.3.64.0/18145.3.64.1 to 145.3.127.254145.3.127.25516,382
15145.3.128.0/18145.3.128.1 to 145.3.191.254145.3.191.25516,382
16145.3.192.0/18145.3.192.1 to 145.3.255.254145.3.255.25516,382
17145.4.0.0/18145.4.0.1 to 145.4.63.254145.4.63.25516,382
18145.4.64.0/18145.4.64.1 to 145.4.127.254145.4.127.25516,382
19145.4.128.0/18145.4.128.1 to 145.4.191.254145.4.191.25516,382
20145.4.192.0/18145.4.192.1 to 145.4.255.254145.4.255.25516,382
21145.5.0.0/18145.5.0.1 to 145.5.63.254145.5.63.25516,382
22145.5.64.0/18145.5.64.1 to 145.5.127.254145.5.127.25516,382
23145.5.128.0/18145.5.128.1 to 145.5.191.254145.5.191.25516,382
24145.5.192.0/18145.5.192.1 to 145.5.255.254145.5.255.25516,382
25145.6.0.0/18145.6.0.1 to 145.6.63.254145.6.63.25516,382
26145.6.64.0/18145.6.64.1 to 145.6.127.254145.6.127.25516,382
27145.6.128.0/18145.6.128.1 to 145.6.191.254145.6.191.25516,382
28145.6.192.0/18145.6.192.1 to 145.6.255.254145.6.255.25516,382
29145.7.0.0/18145.7.0.1 to 145.7.63.254145.7.63.25516,382
30145.7.64.0/18145.7.64.1 to 145.7.127.254145.7.127.25516,382
31145.7.128.0/18145.7.128.1 to 145.7.191.254145.7.191.25516,382
32145.7.192.0/18145.7.192.1 to 145.7.255.254145.7.255.25516,382
33145.8.0.0/18145.8.0.1 to 145.8.63.254145.8.63.25516,382
34145.8.64.0/18145.8.64.1 to 145.8.127.254145.8.127.25516,382
35145.8.128.0/18145.8.128.1 to 145.8.191.254145.8.191.25516,382
36145.8.192.0/18145.8.192.1 to 145.8.255.254145.8.255.25516,382
37145.9.0.0/18145.9.0.1 to 145.9.63.254145.9.63.25516,382
38145.9.64.0/18145.9.64.1 to 145.9.127.254145.9.127.25516,382
39145.9.128.0/18145.9.128.1 to 145.9.191.254145.9.191.25516,382
40145.9.192.0/18145.9.192.1 to 145.9.255.254145.9.255.25516,382
41145.10.0.0/18145.10.0.1 to 145.10.63.254145.10.63.25516,382
42145.10.64.0/18145.10.64.1 to 145.10.127.254145.10.127.25516,382
43145.10.128.0/18145.10.128.1 to 145.10.191.254145.10.191.25516,382
44145.10.192.0/18145.10.192.1 to 145.10.255.254145.10.255.25516,382
45145.11.0.0/18145.11.0.1 to 145.11.63.254145.11.63.25516,382
46145.11.64.0/18145.11.64.1 to 145.11.127.254145.11.127.25516,382
47145.11.128.0/18145.11.128.1 to 145.11.191.254145.11.191.25516,382
48145.11.192.0/18145.11.192.1 to 145.11.255.254145.11.255.25516,382
49145.12.0.0/18145.12.0.1 to 145.12.63.254145.12.63.25516,382
50145.12.64.0/18145.12.64.1 to 145.12.127.254145.12.127.25516,382
51145.12.128.0/18145.12.128.1 to 145.12.191.254145.12.191.25516,382
52145.12.192.0/18145.12.192.1 to 145.12.255.254145.12.255.25516,382
53145.13.0.0/18145.13.0.1 to 145.13.63.254145.13.63.25516,382
54145.13.64.0/18145.13.64.1 to 145.13.127.254145.13.127.25516,382
55145.13.128.0/18145.13.128.1 to 145.13.191.254145.13.191.25516,382
56145.13.192.0/18145.13.192.1 to 145.13.255.254145.13.255.25516,382
57145.14.0.0/18145.14.0.1 to 145.14.63.254145.14.63.25516,382
58145.14.64.0/18145.14.64.1 to 145.14.127.254145.14.127.25516,382
59145.14.128.0/18145.14.128.1 to 145.14.191.254145.14.191.25516,382
60145.14.192.0/18145.14.192.1 to 145.14.255.254145.14.255.25516,382
61145.15.0.0/18145.15.0.1 to 145.15.63.254145.15.63.25516,382
62145.15.64.0/18145.15.64.1 to 145.15.127.254145.15.127.25516,382
63145.15.128.0/18145.15.128.1 to 145.15.191.254145.15.191.25516,382
64145.15.192.0/18145.15.192.1 to 145.15.255.254145.15.255.25516,382
65145.16.0.0/18145.16.0.1 to 145.16.63.254145.16.63.25516,382
66145.16.64.0/18145.16.64.1 to 145.16.127.254145.16.127.25516,382
67145.16.128.0/18145.16.128.1 to 145.16.191.254145.16.191.25516,382
68145.16.192.0/18145.16.192.1 to 145.16.255.254145.16.255.25516,382
69145.17.0.0/18145.17.0.1 to 145.17.63.254145.17.63.25516,382
70145.17.64.0/18145.17.64.1 to 145.17.127.254145.17.127.25516,382
71145.17.128.0/18145.17.128.1 to 145.17.191.254145.17.191.25516,382
72145.17.192.0/18145.17.192.1 to 145.17.255.254145.17.255.25516,382
73145.18.0.0/18145.18.0.1 to 145.18.63.254145.18.63.25516,382
74145.18.64.0/18145.18.64.1 to 145.18.127.254145.18.127.25516,382
75145.18.128.0/18145.18.128.1 to 145.18.191.254145.18.191.25516,382
76145.18.192.0/18145.18.192.1 to 145.18.255.254145.18.255.25516,382
77145.19.0.0/18145.19.0.1 to 145.19.63.254145.19.63.25516,382
78145.19.64.0/18145.19.64.1 to 145.19.127.254145.19.127.25516,382
79145.19.128.0/18145.19.128.1 to 145.19.191.254145.19.191.25516,382
80145.19.192.0/18145.19.192.1 to 145.19.255.254145.19.255.25516,382
81145.20.0.0/18145.20.0.1 to 145.20.63.254145.20.63.25516,382
82145.20.64.0/18145.20.64.1 to 145.20.127.254145.20.127.25516,382
83145.20.128.0/18145.20.128.1 to 145.20.191.254145.20.191.25516,382
84145.20.192.0/18145.20.192.1 to 145.20.255.254145.20.255.25516,382
85145.21.0.0/18145.21.0.1 to 145.21.63.254145.21.63.25516,382
86145.21.64.0/18145.21.64.1 to 145.21.127.254145.21.127.25516,382
87145.21.128.0/18145.21.128.1 to 145.21.191.254145.21.191.25516,382
88145.21.192.0/18145.21.192.1 to 145.21.255.254145.21.255.25516,382
89145.22.0.0/18145.22.0.1 to 145.22.63.254145.22.63.25516,382
90145.22.64.0/18145.22.64.1 to 145.22.127.254145.22.127.25516,382
91145.22.128.0/18145.22.128.1 to 145.22.191.254145.22.191.25516,382
92145.22.192.0/18145.22.192.1 to 145.22.255.254145.22.255.25516,382
93145.23.0.0/18145.23.0.1 to 145.23.63.254145.23.63.25516,382
94145.23.64.0/18145.23.64.1 to 145.23.127.254145.23.127.25516,382
95145.23.128.0/18145.23.128.1 to 145.23.191.254145.23.191.25516,382
96145.23.192.0/18145.23.192.1 to 145.23.255.254145.23.255.25516,382
97145.24.0.0/18145.24.0.1 to 145.24.63.254145.24.63.25516,382
98145.24.64.0/18145.24.64.1 to 145.24.127.254145.24.127.25516,382
99145.24.128.0/18145.24.128.1 to 145.24.191.254145.24.191.25516,382
100145.24.192.0/18145.24.192.1 to 145.24.255.254145.24.255.25516,382
101145.25.0.0/18145.25.0.1 to 145.25.63.254145.25.63.25516,382
102145.25.64.0/18145.25.64.1 to 145.25.127.254145.25.127.25516,382
103145.25.128.0/18145.25.128.1 to 145.25.191.254145.25.191.25516,382
104145.25.192.0/18145.25.192.1 to 145.25.255.254145.25.255.25516,382
105145.26.0.0/18145.26.0.1 to 145.26.63.254145.26.63.25516,382
106145.26.64.0/18145.26.64.1 to 145.26.127.254145.26.127.25516,382
107145.26.128.0/18145.26.128.1 to 145.26.191.254145.26.191.25516,382
108145.26.192.0/18145.26.192.1 to 145.26.255.254145.26.255.25516,382
109145.27.0.0/18145.27.0.1 to 145.27.63.254145.27.63.25516,382
110145.27.64.0/18145.27.64.1 to 145.27.127.254145.27.127.25516,382
111145.27.128.0/18145.27.128.1 to 145.27.191.254145.27.191.25516,382
112145.27.192.0/18145.27.192.1 to 145.27.255.254145.27.255.25516,382
113145.28.0.0/18145.28.0.1 to 145.28.63.254145.28.63.25516,382
114145.28.64.0/18145.28.64.1 to 145.28.127.254145.28.127.25516,382
115145.28.128.0/18145.28.128.1 to 145.28.191.254145.28.191.25516,382
116145.28.192.0/18145.28.192.1 to 145.28.255.254145.28.255.25516,382
117145.29.0.0/18145.29.0.1 to 145.29.63.254145.29.63.25516,382
118145.29.64.0/18145.29.64.1 to 145.29.127.254145.29.127.25516,382
119145.29.128.0/18145.29.128.1 to 145.29.191.254145.29.191.25516,382
120145.29.192.0/18145.29.192.1 to 145.29.255.254145.29.255.25516,382
121145.30.0.0/18145.30.0.1 to 145.30.63.254145.30.63.25516,382
122145.30.64.0/18145.30.64.1 to 145.30.127.254145.30.127.25516,382
123145.30.128.0/18145.30.128.1 to 145.30.191.254145.30.191.25516,382
124145.30.192.0/18145.30.192.1 to 145.30.255.254145.30.255.25516,382
125145.31.0.0/18145.31.0.1 to 145.31.63.254145.31.63.25516,382
126145.31.64.0/18145.31.64.1 to 145.31.127.254145.31.127.25516,382
127145.31.128.0/18145.31.128.1 to 145.31.191.254145.31.191.25516,382
128145.31.192.0/18145.31.192.1 to 145.31.255.254145.31.255.25516,382
129145.32.0.0/18145.32.0.1 to 145.32.63.254145.32.63.25516,382
130145.32.64.0/18145.32.64.1 to 145.32.127.254145.32.127.25516,382
131145.32.128.0/18145.32.128.1 to 145.32.191.254145.32.191.25516,382
132145.32.192.0/18145.32.192.1 to 145.32.255.254145.32.255.25516,382
133145.33.0.0/18145.33.0.1 to 145.33.63.254145.33.63.25516,382
134145.33.64.0/18145.33.64.1 to 145.33.127.254145.33.127.25516,382
135145.33.128.0/18145.33.128.1 to 145.33.191.254145.33.191.25516,382
136145.33.192.0/18145.33.192.1 to 145.33.255.254145.33.255.25516,382
137145.34.0.0/18145.34.0.1 to 145.34.63.254145.34.63.25516,382
138145.34.64.0/18145.34.64.1 to 145.34.127.254145.34.127.25516,382
139145.34.128.0/18145.34.128.1 to 145.34.191.254145.34.191.25516,382
140145.34.192.0/18145.34.192.1 to 145.34.255.254145.34.255.25516,382
141145.35.0.0/18145.35.0.1 to 145.35.63.254145.35.63.25516,382
142145.35.64.0/18145.35.64.1 to 145.35.127.254145.35.127.25516,382
143145.35.128.0/18145.35.128.1 to 145.35.191.254145.35.191.25516,382
144145.35.192.0/18145.35.192.1 to 145.35.255.254145.35.255.25516,382
145145.36.0.0/18145.36.0.1 to 145.36.63.254145.36.63.25516,382
146145.36.64.0/18145.36.64.1 to 145.36.127.254145.36.127.25516,382
147145.36.128.0/18145.36.128.1 to 145.36.191.254145.36.191.25516,382
148145.36.192.0/18145.36.192.1 to 145.36.255.254145.36.255.25516,382
149145.37.0.0/18145.37.0.1 to 145.37.63.254145.37.63.25516,382
150145.37.64.0/18145.37.64.1 to 145.37.127.254145.37.127.25516,382
151145.37.128.0/18145.37.128.1 to 145.37.191.254145.37.191.25516,382
152145.37.192.0/18145.37.192.1 to 145.37.255.254145.37.255.25516,382
153145.38.0.0/18145.38.0.1 to 145.38.63.254145.38.63.25516,382
154145.38.64.0/18145.38.64.1 to 145.38.127.254145.38.127.25516,382
155145.38.128.0/18145.38.128.1 to 145.38.191.254145.38.191.25516,382
156145.38.192.0/18145.38.192.1 to 145.38.255.254145.38.255.25516,382
157145.39.0.0/18145.39.0.1 to 145.39.63.254145.39.63.25516,382
158145.39.64.0/18145.39.64.1 to 145.39.127.254145.39.127.25516,382
159145.39.128.0/18145.39.128.1 to 145.39.191.254145.39.191.25516,382
160145.39.192.0/18145.39.192.1 to 145.39.255.254145.39.255.25516,382
161145.40.0.0/18145.40.0.1 to 145.40.63.254145.40.63.25516,382
162145.40.64.0/18145.40.64.1 to 145.40.127.254145.40.127.25516,382
163145.40.128.0/18145.40.128.1 to 145.40.191.254145.40.191.25516,382
164145.40.192.0/18145.40.192.1 to 145.40.255.254145.40.255.25516,382
165145.41.0.0/18145.41.0.1 to 145.41.63.254145.41.63.25516,382
166145.41.64.0/18145.41.64.1 to 145.41.127.254145.41.127.25516,382
167145.41.128.0/18145.41.128.1 to 145.41.191.254145.41.191.25516,382
168145.41.192.0/18145.41.192.1 to 145.41.255.254145.41.255.25516,382
169145.42.0.0/18145.42.0.1 to 145.42.63.254145.42.63.25516,382
170145.42.64.0/18145.42.64.1 to 145.42.127.254145.42.127.25516,382
171145.42.128.0/18145.42.128.1 to 145.42.191.254145.42.191.25516,382
172145.42.192.0/18145.42.192.1 to 145.42.255.254145.42.255.25516,382
173145.43.0.0/18145.43.0.1 to 145.43.63.254145.43.63.25516,382
174145.43.64.0/18145.43.64.1 to 145.43.127.254145.43.127.25516,382
175145.43.128.0/18145.43.128.1 to 145.43.191.254145.43.191.25516,382
176145.43.192.0/18145.43.192.1 to 145.43.255.254145.43.255.25516,382
177145.44.0.0/18145.44.0.1 to 145.44.63.254145.44.63.25516,382
178145.44.64.0/18145.44.64.1 to 145.44.127.254145.44.127.25516,382
179145.44.128.0/18145.44.128.1 to 145.44.191.254145.44.191.25516,382
180145.44.192.0/18145.44.192.1 to 145.44.255.254145.44.255.25516,382
181145.45.0.0/18145.45.0.1 to 145.45.63.254145.45.63.25516,382
182145.45.64.0/18145.45.64.1 to 145.45.127.254145.45.127.25516,382
183145.45.128.0/18145.45.128.1 to 145.45.191.254145.45.191.25516,382
184145.45.192.0/18145.45.192.1 to 145.45.255.254145.45.255.25516,382
185145.46.0.0/18145.46.0.1 to 145.46.63.254145.46.63.25516,382
186145.46.64.0/18145.46.64.1 to 145.46.127.254145.46.127.25516,382
187145.46.128.0/18145.46.128.1 to 145.46.191.254145.46.191.25516,382
188145.46.192.0/18145.46.192.1 to 145.46.255.254145.46.255.25516,382
189145.47.0.0/18145.47.0.1 to 145.47.63.254145.47.63.25516,382
190145.47.64.0/18145.47.64.1 to 145.47.127.254145.47.127.25516,382
191145.47.128.0/18145.47.128.1 to 145.47.191.254145.47.191.25516,382
192145.47.192.0/18145.47.192.1 to 145.47.255.254145.47.255.25516,382
193145.48.0.0/18145.48.0.1 to 145.48.63.254145.48.63.25516,382
194145.48.64.0/18145.48.64.1 to 145.48.127.254145.48.127.25516,382
195145.48.128.0/18145.48.128.1 to 145.48.191.254145.48.191.25516,382
196145.48.192.0/18145.48.192.1 to 145.48.255.254145.48.255.25516,382
197145.49.0.0/18145.49.0.1 to 145.49.63.254145.49.63.25516,382
198145.49.64.0/18145.49.64.1 to 145.49.127.254145.49.127.25516,382
199145.49.128.0/18145.49.128.1 to 145.49.191.254145.49.191.25516,382
200145.49.192.0/18145.49.192.1 to 145.49.255.254145.49.255.25516,382
201145.50.0.0/18145.50.0.1 to 145.50.63.254145.50.63.25516,382
202145.50.64.0/18145.50.64.1 to 145.50.127.254145.50.127.25516,382
203145.50.128.0/18145.50.128.1 to 145.50.191.254145.50.191.25516,382
204145.50.192.0/18145.50.192.1 to 145.50.255.254145.50.255.25516,382
205145.51.0.0/18145.51.0.1 to 145.51.63.254145.51.63.25516,382
206145.51.64.0/18145.51.64.1 to 145.51.127.254145.51.127.25516,382
207145.51.128.0/18145.51.128.1 to 145.51.191.254145.51.191.25516,382
208145.51.192.0/18145.51.192.1 to 145.51.255.254145.51.255.25516,382
209145.52.0.0/18145.52.0.1 to 145.52.63.254145.52.63.25516,382
210145.52.64.0/18145.52.64.1 to 145.52.127.254145.52.127.25516,382
211145.52.128.0/18145.52.128.1 to 145.52.191.254145.52.191.25516,382
212145.52.192.0/18145.52.192.1 to 145.52.255.254145.52.255.25516,382
213145.53.0.0/18145.53.0.1 to 145.53.63.254145.53.63.25516,382
214145.53.64.0/18145.53.64.1 to 145.53.127.254145.53.127.25516,382
215145.53.128.0/18145.53.128.1 to 145.53.191.254145.53.191.25516,382
216145.53.192.0/18145.53.192.1 to 145.53.255.254145.53.255.25516,382
217145.54.0.0/18145.54.0.1 to 145.54.63.254145.54.63.25516,382
218145.54.64.0/18145.54.64.1 to 145.54.127.254145.54.127.25516,382
219145.54.128.0/18145.54.128.1 to 145.54.191.254145.54.191.25516,382
220145.54.192.0/18145.54.192.1 to 145.54.255.254145.54.255.25516,382
221145.55.0.0/18145.55.0.1 to 145.55.63.254145.55.63.25516,382
222145.55.64.0/18145.55.64.1 to 145.55.127.254145.55.127.25516,382
223145.55.128.0/18145.55.128.1 to 145.55.191.254145.55.191.25516,382
224145.55.192.0/18145.55.192.1 to 145.55.255.254145.55.255.25516,382
225145.56.0.0/18145.56.0.1 to 145.56.63.254145.56.63.25516,382
226145.56.64.0/18145.56.64.1 to 145.56.127.254145.56.127.25516,382
227145.56.128.0/18145.56.128.1 to 145.56.191.254145.56.191.25516,382
228145.56.192.0/18145.56.192.1 to 145.56.255.254145.56.255.25516,382
229145.57.0.0/18145.57.0.1 to 145.57.63.254145.57.63.25516,382
230145.57.64.0/18145.57.64.1 to 145.57.127.254145.57.127.25516,382
231145.57.128.0/18145.57.128.1 to 145.57.191.254145.57.191.25516,382
232145.57.192.0/18145.57.192.1 to 145.57.255.254145.57.255.25516,382
233145.58.0.0/18145.58.0.1 to 145.58.63.254145.58.63.25516,382
234145.58.64.0/18145.58.64.1 to 145.58.127.254145.58.127.25516,382
235145.58.128.0/18145.58.128.1 to 145.58.191.254145.58.191.25516,382
236145.58.192.0/18145.58.192.1 to 145.58.255.254145.58.255.25516,382
237145.59.0.0/18145.59.0.1 to 145.59.63.254145.59.63.25516,382
238145.59.64.0/18145.59.64.1 to 145.59.127.254145.59.127.25516,382
239145.59.128.0/18145.59.128.1 to 145.59.191.254145.59.191.25516,382
240145.59.192.0/18145.59.192.1 to 145.59.255.254145.59.255.25516,382
241145.60.0.0/18145.60.0.1 to 145.60.63.254145.60.63.25516,382
242145.60.64.0/18145.60.64.1 to 145.60.127.254145.60.127.25516,382
243145.60.128.0/18145.60.128.1 to 145.60.191.254145.60.191.25516,382
244145.60.192.0/18145.60.192.1 to 145.60.255.254145.60.255.25516,382
245145.61.0.0/18145.61.0.1 to 145.61.63.254145.61.63.25516,382
246145.61.64.0/18145.61.64.1 to 145.61.127.254145.61.127.25516,382
247145.61.128.0/18145.61.128.1 to 145.61.191.254145.61.191.25516,382
248145.61.192.0/18145.61.192.1 to 145.61.255.254145.61.255.25516,382
249145.62.0.0/18145.62.0.1 to 145.62.63.254145.62.63.25516,382
250145.62.64.0/18145.62.64.1 to 145.62.127.254145.62.127.25516,382
251145.62.128.0/18145.62.128.1 to 145.62.191.254145.62.191.25516,382
252145.62.192.0/18145.62.192.1 to 145.62.255.254145.62.255.25516,382
253145.63.0.0/18145.63.0.1 to 145.63.63.254145.63.63.25516,382
254145.63.64.0/18145.63.64.1 to 145.63.127.254145.63.127.25516,382
255145.63.128.0/18145.63.128.1 to 145.63.191.254145.63.191.25516,382
256145.63.192.0/18145.63.192.1 to 145.63.255.254145.63.255.25516,382

IPv4 CIDR reference (/0 to /32)

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

IPv6 prefix reference

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

Private and special ranges

IPv4

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

IPv6

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

About this tool

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

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

Common questions

Why are two addresses lost in every IPv4 subnet?

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

What size of IPv6 network should a LAN use?

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

What is a wildcard mask?

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

Which ranges can I use inside an office?

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