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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.

Network143.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
143.0.0.0
Broadcast address
143.255.255.255
First usable
143.0.0.1
Last usable
143.255.255.254
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 8F000000 · Integer 2399141888 to 2415919103
Reverse DNS zone
143.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10001111..00000000.00000000.00000000143.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network10001111..00000000.00000000.00000000143.0.0.0
Broadcast10001111..11111111.11111111.11111111143.255.255.255
Split into smaller subnets/19
/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)

143.0.0.0/8 makes 2,048 subnets of /19; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1143.0.0.0/19143.0.0.1 to 143.0.31.254143.0.31.2558,190
2143.0.32.0/19143.0.32.1 to 143.0.63.254143.0.63.2558,190
3143.0.64.0/19143.0.64.1 to 143.0.95.254143.0.95.2558,190
4143.0.96.0/19143.0.96.1 to 143.0.127.254143.0.127.2558,190
5143.0.128.0/19143.0.128.1 to 143.0.159.254143.0.159.2558,190
6143.0.160.0/19143.0.160.1 to 143.0.191.254143.0.191.2558,190
7143.0.192.0/19143.0.192.1 to 143.0.223.254143.0.223.2558,190
8143.0.224.0/19143.0.224.1 to 143.0.255.254143.0.255.2558,190
9143.1.0.0/19143.1.0.1 to 143.1.31.254143.1.31.2558,190
10143.1.32.0/19143.1.32.1 to 143.1.63.254143.1.63.2558,190
11143.1.64.0/19143.1.64.1 to 143.1.95.254143.1.95.2558,190
12143.1.96.0/19143.1.96.1 to 143.1.127.254143.1.127.2558,190
13143.1.128.0/19143.1.128.1 to 143.1.159.254143.1.159.2558,190
14143.1.160.0/19143.1.160.1 to 143.1.191.254143.1.191.2558,190
15143.1.192.0/19143.1.192.1 to 143.1.223.254143.1.223.2558,190
16143.1.224.0/19143.1.224.1 to 143.1.255.254143.1.255.2558,190
17143.2.0.0/19143.2.0.1 to 143.2.31.254143.2.31.2558,190
18143.2.32.0/19143.2.32.1 to 143.2.63.254143.2.63.2558,190
19143.2.64.0/19143.2.64.1 to 143.2.95.254143.2.95.2558,190
20143.2.96.0/19143.2.96.1 to 143.2.127.254143.2.127.2558,190
21143.2.128.0/19143.2.128.1 to 143.2.159.254143.2.159.2558,190
22143.2.160.0/19143.2.160.1 to 143.2.191.254143.2.191.2558,190
23143.2.192.0/19143.2.192.1 to 143.2.223.254143.2.223.2558,190
24143.2.224.0/19143.2.224.1 to 143.2.255.254143.2.255.2558,190
25143.3.0.0/19143.3.0.1 to 143.3.31.254143.3.31.2558,190
26143.3.32.0/19143.3.32.1 to 143.3.63.254143.3.63.2558,190
27143.3.64.0/19143.3.64.1 to 143.3.95.254143.3.95.2558,190
28143.3.96.0/19143.3.96.1 to 143.3.127.254143.3.127.2558,190
29143.3.128.0/19143.3.128.1 to 143.3.159.254143.3.159.2558,190
30143.3.160.0/19143.3.160.1 to 143.3.191.254143.3.191.2558,190
31143.3.192.0/19143.3.192.1 to 143.3.223.254143.3.223.2558,190
32143.3.224.0/19143.3.224.1 to 143.3.255.254143.3.255.2558,190
33143.4.0.0/19143.4.0.1 to 143.4.31.254143.4.31.2558,190
34143.4.32.0/19143.4.32.1 to 143.4.63.254143.4.63.2558,190
35143.4.64.0/19143.4.64.1 to 143.4.95.254143.4.95.2558,190
36143.4.96.0/19143.4.96.1 to 143.4.127.254143.4.127.2558,190
37143.4.128.0/19143.4.128.1 to 143.4.159.254143.4.159.2558,190
38143.4.160.0/19143.4.160.1 to 143.4.191.254143.4.191.2558,190
39143.4.192.0/19143.4.192.1 to 143.4.223.254143.4.223.2558,190
40143.4.224.0/19143.4.224.1 to 143.4.255.254143.4.255.2558,190
41143.5.0.0/19143.5.0.1 to 143.5.31.254143.5.31.2558,190
42143.5.32.0/19143.5.32.1 to 143.5.63.254143.5.63.2558,190
43143.5.64.0/19143.5.64.1 to 143.5.95.254143.5.95.2558,190
44143.5.96.0/19143.5.96.1 to 143.5.127.254143.5.127.2558,190
45143.5.128.0/19143.5.128.1 to 143.5.159.254143.5.159.2558,190
46143.5.160.0/19143.5.160.1 to 143.5.191.254143.5.191.2558,190
47143.5.192.0/19143.5.192.1 to 143.5.223.254143.5.223.2558,190
48143.5.224.0/19143.5.224.1 to 143.5.255.254143.5.255.2558,190
49143.6.0.0/19143.6.0.1 to 143.6.31.254143.6.31.2558,190
50143.6.32.0/19143.6.32.1 to 143.6.63.254143.6.63.2558,190
51143.6.64.0/19143.6.64.1 to 143.6.95.254143.6.95.2558,190
52143.6.96.0/19143.6.96.1 to 143.6.127.254143.6.127.2558,190
53143.6.128.0/19143.6.128.1 to 143.6.159.254143.6.159.2558,190
54143.6.160.0/19143.6.160.1 to 143.6.191.254143.6.191.2558,190
55143.6.192.0/19143.6.192.1 to 143.6.223.254143.6.223.2558,190
56143.6.224.0/19143.6.224.1 to 143.6.255.254143.6.255.2558,190
57143.7.0.0/19143.7.0.1 to 143.7.31.254143.7.31.2558,190
58143.7.32.0/19143.7.32.1 to 143.7.63.254143.7.63.2558,190
59143.7.64.0/19143.7.64.1 to 143.7.95.254143.7.95.2558,190
60143.7.96.0/19143.7.96.1 to 143.7.127.254143.7.127.2558,190
61143.7.128.0/19143.7.128.1 to 143.7.159.254143.7.159.2558,190
62143.7.160.0/19143.7.160.1 to 143.7.191.254143.7.191.2558,190
63143.7.192.0/19143.7.192.1 to 143.7.223.254143.7.223.2558,190
64143.7.224.0/19143.7.224.1 to 143.7.255.254143.7.255.2558,190
65143.8.0.0/19143.8.0.1 to 143.8.31.254143.8.31.2558,190
66143.8.32.0/19143.8.32.1 to 143.8.63.254143.8.63.2558,190
67143.8.64.0/19143.8.64.1 to 143.8.95.254143.8.95.2558,190
68143.8.96.0/19143.8.96.1 to 143.8.127.254143.8.127.2558,190
69143.8.128.0/19143.8.128.1 to 143.8.159.254143.8.159.2558,190
70143.8.160.0/19143.8.160.1 to 143.8.191.254143.8.191.2558,190
71143.8.192.0/19143.8.192.1 to 143.8.223.254143.8.223.2558,190
72143.8.224.0/19143.8.224.1 to 143.8.255.254143.8.255.2558,190
73143.9.0.0/19143.9.0.1 to 143.9.31.254143.9.31.2558,190
74143.9.32.0/19143.9.32.1 to 143.9.63.254143.9.63.2558,190
75143.9.64.0/19143.9.64.1 to 143.9.95.254143.9.95.2558,190
76143.9.96.0/19143.9.96.1 to 143.9.127.254143.9.127.2558,190
77143.9.128.0/19143.9.128.1 to 143.9.159.254143.9.159.2558,190
78143.9.160.0/19143.9.160.1 to 143.9.191.254143.9.191.2558,190
79143.9.192.0/19143.9.192.1 to 143.9.223.254143.9.223.2558,190
80143.9.224.0/19143.9.224.1 to 143.9.255.254143.9.255.2558,190
81143.10.0.0/19143.10.0.1 to 143.10.31.254143.10.31.2558,190
82143.10.32.0/19143.10.32.1 to 143.10.63.254143.10.63.2558,190
83143.10.64.0/19143.10.64.1 to 143.10.95.254143.10.95.2558,190
84143.10.96.0/19143.10.96.1 to 143.10.127.254143.10.127.2558,190
85143.10.128.0/19143.10.128.1 to 143.10.159.254143.10.159.2558,190
86143.10.160.0/19143.10.160.1 to 143.10.191.254143.10.191.2558,190
87143.10.192.0/19143.10.192.1 to 143.10.223.254143.10.223.2558,190
88143.10.224.0/19143.10.224.1 to 143.10.255.254143.10.255.2558,190
89143.11.0.0/19143.11.0.1 to 143.11.31.254143.11.31.2558,190
90143.11.32.0/19143.11.32.1 to 143.11.63.254143.11.63.2558,190
91143.11.64.0/19143.11.64.1 to 143.11.95.254143.11.95.2558,190
92143.11.96.0/19143.11.96.1 to 143.11.127.254143.11.127.2558,190
93143.11.128.0/19143.11.128.1 to 143.11.159.254143.11.159.2558,190
94143.11.160.0/19143.11.160.1 to 143.11.191.254143.11.191.2558,190
95143.11.192.0/19143.11.192.1 to 143.11.223.254143.11.223.2558,190
96143.11.224.0/19143.11.224.1 to 143.11.255.254143.11.255.2558,190
97143.12.0.0/19143.12.0.1 to 143.12.31.254143.12.31.2558,190
98143.12.32.0/19143.12.32.1 to 143.12.63.254143.12.63.2558,190
99143.12.64.0/19143.12.64.1 to 143.12.95.254143.12.95.2558,190
100143.12.96.0/19143.12.96.1 to 143.12.127.254143.12.127.2558,190
101143.12.128.0/19143.12.128.1 to 143.12.159.254143.12.159.2558,190
102143.12.160.0/19143.12.160.1 to 143.12.191.254143.12.191.2558,190
103143.12.192.0/19143.12.192.1 to 143.12.223.254143.12.223.2558,190
104143.12.224.0/19143.12.224.1 to 143.12.255.254143.12.255.2558,190
105143.13.0.0/19143.13.0.1 to 143.13.31.254143.13.31.2558,190
106143.13.32.0/19143.13.32.1 to 143.13.63.254143.13.63.2558,190
107143.13.64.0/19143.13.64.1 to 143.13.95.254143.13.95.2558,190
108143.13.96.0/19143.13.96.1 to 143.13.127.254143.13.127.2558,190
109143.13.128.0/19143.13.128.1 to 143.13.159.254143.13.159.2558,190
110143.13.160.0/19143.13.160.1 to 143.13.191.254143.13.191.2558,190
111143.13.192.0/19143.13.192.1 to 143.13.223.254143.13.223.2558,190
112143.13.224.0/19143.13.224.1 to 143.13.255.254143.13.255.2558,190
113143.14.0.0/19143.14.0.1 to 143.14.31.254143.14.31.2558,190
114143.14.32.0/19143.14.32.1 to 143.14.63.254143.14.63.2558,190
115143.14.64.0/19143.14.64.1 to 143.14.95.254143.14.95.2558,190
116143.14.96.0/19143.14.96.1 to 143.14.127.254143.14.127.2558,190
117143.14.128.0/19143.14.128.1 to 143.14.159.254143.14.159.2558,190
118143.14.160.0/19143.14.160.1 to 143.14.191.254143.14.191.2558,190
119143.14.192.0/19143.14.192.1 to 143.14.223.254143.14.223.2558,190
120143.14.224.0/19143.14.224.1 to 143.14.255.254143.14.255.2558,190
121143.15.0.0/19143.15.0.1 to 143.15.31.254143.15.31.2558,190
122143.15.32.0/19143.15.32.1 to 143.15.63.254143.15.63.2558,190
123143.15.64.0/19143.15.64.1 to 143.15.95.254143.15.95.2558,190
124143.15.96.0/19143.15.96.1 to 143.15.127.254143.15.127.2558,190
125143.15.128.0/19143.15.128.1 to 143.15.159.254143.15.159.2558,190
126143.15.160.0/19143.15.160.1 to 143.15.191.254143.15.191.2558,190
127143.15.192.0/19143.15.192.1 to 143.15.223.254143.15.223.2558,190
128143.15.224.0/19143.15.224.1 to 143.15.255.254143.15.255.2558,190
129143.16.0.0/19143.16.0.1 to 143.16.31.254143.16.31.2558,190
130143.16.32.0/19143.16.32.1 to 143.16.63.254143.16.63.2558,190
131143.16.64.0/19143.16.64.1 to 143.16.95.254143.16.95.2558,190
132143.16.96.0/19143.16.96.1 to 143.16.127.254143.16.127.2558,190
133143.16.128.0/19143.16.128.1 to 143.16.159.254143.16.159.2558,190
134143.16.160.0/19143.16.160.1 to 143.16.191.254143.16.191.2558,190
135143.16.192.0/19143.16.192.1 to 143.16.223.254143.16.223.2558,190
136143.16.224.0/19143.16.224.1 to 143.16.255.254143.16.255.2558,190
137143.17.0.0/19143.17.0.1 to 143.17.31.254143.17.31.2558,190
138143.17.32.0/19143.17.32.1 to 143.17.63.254143.17.63.2558,190
139143.17.64.0/19143.17.64.1 to 143.17.95.254143.17.95.2558,190
140143.17.96.0/19143.17.96.1 to 143.17.127.254143.17.127.2558,190
141143.17.128.0/19143.17.128.1 to 143.17.159.254143.17.159.2558,190
142143.17.160.0/19143.17.160.1 to 143.17.191.254143.17.191.2558,190
143143.17.192.0/19143.17.192.1 to 143.17.223.254143.17.223.2558,190
144143.17.224.0/19143.17.224.1 to 143.17.255.254143.17.255.2558,190
145143.18.0.0/19143.18.0.1 to 143.18.31.254143.18.31.2558,190
146143.18.32.0/19143.18.32.1 to 143.18.63.254143.18.63.2558,190
147143.18.64.0/19143.18.64.1 to 143.18.95.254143.18.95.2558,190
148143.18.96.0/19143.18.96.1 to 143.18.127.254143.18.127.2558,190
149143.18.128.0/19143.18.128.1 to 143.18.159.254143.18.159.2558,190
150143.18.160.0/19143.18.160.1 to 143.18.191.254143.18.191.2558,190
151143.18.192.0/19143.18.192.1 to 143.18.223.254143.18.223.2558,190
152143.18.224.0/19143.18.224.1 to 143.18.255.254143.18.255.2558,190
153143.19.0.0/19143.19.0.1 to 143.19.31.254143.19.31.2558,190
154143.19.32.0/19143.19.32.1 to 143.19.63.254143.19.63.2558,190
155143.19.64.0/19143.19.64.1 to 143.19.95.254143.19.95.2558,190
156143.19.96.0/19143.19.96.1 to 143.19.127.254143.19.127.2558,190
157143.19.128.0/19143.19.128.1 to 143.19.159.254143.19.159.2558,190
158143.19.160.0/19143.19.160.1 to 143.19.191.254143.19.191.2558,190
159143.19.192.0/19143.19.192.1 to 143.19.223.254143.19.223.2558,190
160143.19.224.0/19143.19.224.1 to 143.19.255.254143.19.255.2558,190
161143.20.0.0/19143.20.0.1 to 143.20.31.254143.20.31.2558,190
162143.20.32.0/19143.20.32.1 to 143.20.63.254143.20.63.2558,190
163143.20.64.0/19143.20.64.1 to 143.20.95.254143.20.95.2558,190
164143.20.96.0/19143.20.96.1 to 143.20.127.254143.20.127.2558,190
165143.20.128.0/19143.20.128.1 to 143.20.159.254143.20.159.2558,190
166143.20.160.0/19143.20.160.1 to 143.20.191.254143.20.191.2558,190
167143.20.192.0/19143.20.192.1 to 143.20.223.254143.20.223.2558,190
168143.20.224.0/19143.20.224.1 to 143.20.255.254143.20.255.2558,190
169143.21.0.0/19143.21.0.1 to 143.21.31.254143.21.31.2558,190
170143.21.32.0/19143.21.32.1 to 143.21.63.254143.21.63.2558,190
171143.21.64.0/19143.21.64.1 to 143.21.95.254143.21.95.2558,190
172143.21.96.0/19143.21.96.1 to 143.21.127.254143.21.127.2558,190
173143.21.128.0/19143.21.128.1 to 143.21.159.254143.21.159.2558,190
174143.21.160.0/19143.21.160.1 to 143.21.191.254143.21.191.2558,190
175143.21.192.0/19143.21.192.1 to 143.21.223.254143.21.223.2558,190
176143.21.224.0/19143.21.224.1 to 143.21.255.254143.21.255.2558,190
177143.22.0.0/19143.22.0.1 to 143.22.31.254143.22.31.2558,190
178143.22.32.0/19143.22.32.1 to 143.22.63.254143.22.63.2558,190
179143.22.64.0/19143.22.64.1 to 143.22.95.254143.22.95.2558,190
180143.22.96.0/19143.22.96.1 to 143.22.127.254143.22.127.2558,190
181143.22.128.0/19143.22.128.1 to 143.22.159.254143.22.159.2558,190
182143.22.160.0/19143.22.160.1 to 143.22.191.254143.22.191.2558,190
183143.22.192.0/19143.22.192.1 to 143.22.223.254143.22.223.2558,190
184143.22.224.0/19143.22.224.1 to 143.22.255.254143.22.255.2558,190
185143.23.0.0/19143.23.0.1 to 143.23.31.254143.23.31.2558,190
186143.23.32.0/19143.23.32.1 to 143.23.63.254143.23.63.2558,190
187143.23.64.0/19143.23.64.1 to 143.23.95.254143.23.95.2558,190
188143.23.96.0/19143.23.96.1 to 143.23.127.254143.23.127.2558,190
189143.23.128.0/19143.23.128.1 to 143.23.159.254143.23.159.2558,190
190143.23.160.0/19143.23.160.1 to 143.23.191.254143.23.191.2558,190
191143.23.192.0/19143.23.192.1 to 143.23.223.254143.23.223.2558,190
192143.23.224.0/19143.23.224.1 to 143.23.255.254143.23.255.2558,190
193143.24.0.0/19143.24.0.1 to 143.24.31.254143.24.31.2558,190
194143.24.32.0/19143.24.32.1 to 143.24.63.254143.24.63.2558,190
195143.24.64.0/19143.24.64.1 to 143.24.95.254143.24.95.2558,190
196143.24.96.0/19143.24.96.1 to 143.24.127.254143.24.127.2558,190
197143.24.128.0/19143.24.128.1 to 143.24.159.254143.24.159.2558,190
198143.24.160.0/19143.24.160.1 to 143.24.191.254143.24.191.2558,190
199143.24.192.0/19143.24.192.1 to 143.24.223.254143.24.223.2558,190
200143.24.224.0/19143.24.224.1 to 143.24.255.254143.24.255.2558,190
201143.25.0.0/19143.25.0.1 to 143.25.31.254143.25.31.2558,190
202143.25.32.0/19143.25.32.1 to 143.25.63.254143.25.63.2558,190
203143.25.64.0/19143.25.64.1 to 143.25.95.254143.25.95.2558,190
204143.25.96.0/19143.25.96.1 to 143.25.127.254143.25.127.2558,190
205143.25.128.0/19143.25.128.1 to 143.25.159.254143.25.159.2558,190
206143.25.160.0/19143.25.160.1 to 143.25.191.254143.25.191.2558,190
207143.25.192.0/19143.25.192.1 to 143.25.223.254143.25.223.2558,190
208143.25.224.0/19143.25.224.1 to 143.25.255.254143.25.255.2558,190
209143.26.0.0/19143.26.0.1 to 143.26.31.254143.26.31.2558,190
210143.26.32.0/19143.26.32.1 to 143.26.63.254143.26.63.2558,190
211143.26.64.0/19143.26.64.1 to 143.26.95.254143.26.95.2558,190
212143.26.96.0/19143.26.96.1 to 143.26.127.254143.26.127.2558,190
213143.26.128.0/19143.26.128.1 to 143.26.159.254143.26.159.2558,190
214143.26.160.0/19143.26.160.1 to 143.26.191.254143.26.191.2558,190
215143.26.192.0/19143.26.192.1 to 143.26.223.254143.26.223.2558,190
216143.26.224.0/19143.26.224.1 to 143.26.255.254143.26.255.2558,190
217143.27.0.0/19143.27.0.1 to 143.27.31.254143.27.31.2558,190
218143.27.32.0/19143.27.32.1 to 143.27.63.254143.27.63.2558,190
219143.27.64.0/19143.27.64.1 to 143.27.95.254143.27.95.2558,190
220143.27.96.0/19143.27.96.1 to 143.27.127.254143.27.127.2558,190
221143.27.128.0/19143.27.128.1 to 143.27.159.254143.27.159.2558,190
222143.27.160.0/19143.27.160.1 to 143.27.191.254143.27.191.2558,190
223143.27.192.0/19143.27.192.1 to 143.27.223.254143.27.223.2558,190
224143.27.224.0/19143.27.224.1 to 143.27.255.254143.27.255.2558,190
225143.28.0.0/19143.28.0.1 to 143.28.31.254143.28.31.2558,190
226143.28.32.0/19143.28.32.1 to 143.28.63.254143.28.63.2558,190
227143.28.64.0/19143.28.64.1 to 143.28.95.254143.28.95.2558,190
228143.28.96.0/19143.28.96.1 to 143.28.127.254143.28.127.2558,190
229143.28.128.0/19143.28.128.1 to 143.28.159.254143.28.159.2558,190
230143.28.160.0/19143.28.160.1 to 143.28.191.254143.28.191.2558,190
231143.28.192.0/19143.28.192.1 to 143.28.223.254143.28.223.2558,190
232143.28.224.0/19143.28.224.1 to 143.28.255.254143.28.255.2558,190
233143.29.0.0/19143.29.0.1 to 143.29.31.254143.29.31.2558,190
234143.29.32.0/19143.29.32.1 to 143.29.63.254143.29.63.2558,190
235143.29.64.0/19143.29.64.1 to 143.29.95.254143.29.95.2558,190
236143.29.96.0/19143.29.96.1 to 143.29.127.254143.29.127.2558,190
237143.29.128.0/19143.29.128.1 to 143.29.159.254143.29.159.2558,190
238143.29.160.0/19143.29.160.1 to 143.29.191.254143.29.191.2558,190
239143.29.192.0/19143.29.192.1 to 143.29.223.254143.29.223.2558,190
240143.29.224.0/19143.29.224.1 to 143.29.255.254143.29.255.2558,190
241143.30.0.0/19143.30.0.1 to 143.30.31.254143.30.31.2558,190
242143.30.32.0/19143.30.32.1 to 143.30.63.254143.30.63.2558,190
243143.30.64.0/19143.30.64.1 to 143.30.95.254143.30.95.2558,190
244143.30.96.0/19143.30.96.1 to 143.30.127.254143.30.127.2558,190
245143.30.128.0/19143.30.128.1 to 143.30.159.254143.30.159.2558,190
246143.30.160.0/19143.30.160.1 to 143.30.191.254143.30.191.2558,190
247143.30.192.0/19143.30.192.1 to 143.30.223.254143.30.223.2558,190
248143.30.224.0/19143.30.224.1 to 143.30.255.254143.30.255.2558,190
249143.31.0.0/19143.31.0.1 to 143.31.31.254143.31.31.2558,190
250143.31.32.0/19143.31.32.1 to 143.31.63.254143.31.63.2558,190
251143.31.64.0/19143.31.64.1 to 143.31.95.254143.31.95.2558,190
252143.31.96.0/19143.31.96.1 to 143.31.127.254143.31.127.2558,190
253143.31.128.0/19143.31.128.1 to 143.31.159.254143.31.159.2558,190
254143.31.160.0/19143.31.160.1 to 143.31.191.254143.31.191.2558,190
255143.31.192.0/19143.31.192.1 to 143.31.223.254143.31.223.2558,190
256143.31.224.0/19143.31.224.1 to 143.31.255.254143.31.255.2558,190

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.