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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.

Network178.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
178.0.0.0
Broadcast address
178.255.255.255
First usable
178.0.0.1
Last usable
178.255.255.254
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 B2000000 · Integer 2986344448 to 3003121663
Reverse DNS zone
178.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10110010..00000000.00000000.00000000178.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network10110010..00000000.00000000.00000000178.0.0.0
Broadcast10110010..11111111.11111111.11111111178.255.255.255
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)

178.0.0.0/8 makes 2,048 subnets of /19; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1178.0.0.0/19178.0.0.1 to 178.0.31.254178.0.31.2558,190
2178.0.32.0/19178.0.32.1 to 178.0.63.254178.0.63.2558,190
3178.0.64.0/19178.0.64.1 to 178.0.95.254178.0.95.2558,190
4178.0.96.0/19178.0.96.1 to 178.0.127.254178.0.127.2558,190
5178.0.128.0/19178.0.128.1 to 178.0.159.254178.0.159.2558,190
6178.0.160.0/19178.0.160.1 to 178.0.191.254178.0.191.2558,190
7178.0.192.0/19178.0.192.1 to 178.0.223.254178.0.223.2558,190
8178.0.224.0/19178.0.224.1 to 178.0.255.254178.0.255.2558,190
9178.1.0.0/19178.1.0.1 to 178.1.31.254178.1.31.2558,190
10178.1.32.0/19178.1.32.1 to 178.1.63.254178.1.63.2558,190
11178.1.64.0/19178.1.64.1 to 178.1.95.254178.1.95.2558,190
12178.1.96.0/19178.1.96.1 to 178.1.127.254178.1.127.2558,190
13178.1.128.0/19178.1.128.1 to 178.1.159.254178.1.159.2558,190
14178.1.160.0/19178.1.160.1 to 178.1.191.254178.1.191.2558,190
15178.1.192.0/19178.1.192.1 to 178.1.223.254178.1.223.2558,190
16178.1.224.0/19178.1.224.1 to 178.1.255.254178.1.255.2558,190
17178.2.0.0/19178.2.0.1 to 178.2.31.254178.2.31.2558,190
18178.2.32.0/19178.2.32.1 to 178.2.63.254178.2.63.2558,190
19178.2.64.0/19178.2.64.1 to 178.2.95.254178.2.95.2558,190
20178.2.96.0/19178.2.96.1 to 178.2.127.254178.2.127.2558,190
21178.2.128.0/19178.2.128.1 to 178.2.159.254178.2.159.2558,190
22178.2.160.0/19178.2.160.1 to 178.2.191.254178.2.191.2558,190
23178.2.192.0/19178.2.192.1 to 178.2.223.254178.2.223.2558,190
24178.2.224.0/19178.2.224.1 to 178.2.255.254178.2.255.2558,190
25178.3.0.0/19178.3.0.1 to 178.3.31.254178.3.31.2558,190
26178.3.32.0/19178.3.32.1 to 178.3.63.254178.3.63.2558,190
27178.3.64.0/19178.3.64.1 to 178.3.95.254178.3.95.2558,190
28178.3.96.0/19178.3.96.1 to 178.3.127.254178.3.127.2558,190
29178.3.128.0/19178.3.128.1 to 178.3.159.254178.3.159.2558,190
30178.3.160.0/19178.3.160.1 to 178.3.191.254178.3.191.2558,190
31178.3.192.0/19178.3.192.1 to 178.3.223.254178.3.223.2558,190
32178.3.224.0/19178.3.224.1 to 178.3.255.254178.3.255.2558,190
33178.4.0.0/19178.4.0.1 to 178.4.31.254178.4.31.2558,190
34178.4.32.0/19178.4.32.1 to 178.4.63.254178.4.63.2558,190
35178.4.64.0/19178.4.64.1 to 178.4.95.254178.4.95.2558,190
36178.4.96.0/19178.4.96.1 to 178.4.127.254178.4.127.2558,190
37178.4.128.0/19178.4.128.1 to 178.4.159.254178.4.159.2558,190
38178.4.160.0/19178.4.160.1 to 178.4.191.254178.4.191.2558,190
39178.4.192.0/19178.4.192.1 to 178.4.223.254178.4.223.2558,190
40178.4.224.0/19178.4.224.1 to 178.4.255.254178.4.255.2558,190
41178.5.0.0/19178.5.0.1 to 178.5.31.254178.5.31.2558,190
42178.5.32.0/19178.5.32.1 to 178.5.63.254178.5.63.2558,190
43178.5.64.0/19178.5.64.1 to 178.5.95.254178.5.95.2558,190
44178.5.96.0/19178.5.96.1 to 178.5.127.254178.5.127.2558,190
45178.5.128.0/19178.5.128.1 to 178.5.159.254178.5.159.2558,190
46178.5.160.0/19178.5.160.1 to 178.5.191.254178.5.191.2558,190
47178.5.192.0/19178.5.192.1 to 178.5.223.254178.5.223.2558,190
48178.5.224.0/19178.5.224.1 to 178.5.255.254178.5.255.2558,190
49178.6.0.0/19178.6.0.1 to 178.6.31.254178.6.31.2558,190
50178.6.32.0/19178.6.32.1 to 178.6.63.254178.6.63.2558,190
51178.6.64.0/19178.6.64.1 to 178.6.95.254178.6.95.2558,190
52178.6.96.0/19178.6.96.1 to 178.6.127.254178.6.127.2558,190
53178.6.128.0/19178.6.128.1 to 178.6.159.254178.6.159.2558,190
54178.6.160.0/19178.6.160.1 to 178.6.191.254178.6.191.2558,190
55178.6.192.0/19178.6.192.1 to 178.6.223.254178.6.223.2558,190
56178.6.224.0/19178.6.224.1 to 178.6.255.254178.6.255.2558,190
57178.7.0.0/19178.7.0.1 to 178.7.31.254178.7.31.2558,190
58178.7.32.0/19178.7.32.1 to 178.7.63.254178.7.63.2558,190
59178.7.64.0/19178.7.64.1 to 178.7.95.254178.7.95.2558,190
60178.7.96.0/19178.7.96.1 to 178.7.127.254178.7.127.2558,190
61178.7.128.0/19178.7.128.1 to 178.7.159.254178.7.159.2558,190
62178.7.160.0/19178.7.160.1 to 178.7.191.254178.7.191.2558,190
63178.7.192.0/19178.7.192.1 to 178.7.223.254178.7.223.2558,190
64178.7.224.0/19178.7.224.1 to 178.7.255.254178.7.255.2558,190
65178.8.0.0/19178.8.0.1 to 178.8.31.254178.8.31.2558,190
66178.8.32.0/19178.8.32.1 to 178.8.63.254178.8.63.2558,190
67178.8.64.0/19178.8.64.1 to 178.8.95.254178.8.95.2558,190
68178.8.96.0/19178.8.96.1 to 178.8.127.254178.8.127.2558,190
69178.8.128.0/19178.8.128.1 to 178.8.159.254178.8.159.2558,190
70178.8.160.0/19178.8.160.1 to 178.8.191.254178.8.191.2558,190
71178.8.192.0/19178.8.192.1 to 178.8.223.254178.8.223.2558,190
72178.8.224.0/19178.8.224.1 to 178.8.255.254178.8.255.2558,190
73178.9.0.0/19178.9.0.1 to 178.9.31.254178.9.31.2558,190
74178.9.32.0/19178.9.32.1 to 178.9.63.254178.9.63.2558,190
75178.9.64.0/19178.9.64.1 to 178.9.95.254178.9.95.2558,190
76178.9.96.0/19178.9.96.1 to 178.9.127.254178.9.127.2558,190
77178.9.128.0/19178.9.128.1 to 178.9.159.254178.9.159.2558,190
78178.9.160.0/19178.9.160.1 to 178.9.191.254178.9.191.2558,190
79178.9.192.0/19178.9.192.1 to 178.9.223.254178.9.223.2558,190
80178.9.224.0/19178.9.224.1 to 178.9.255.254178.9.255.2558,190
81178.10.0.0/19178.10.0.1 to 178.10.31.254178.10.31.2558,190
82178.10.32.0/19178.10.32.1 to 178.10.63.254178.10.63.2558,190
83178.10.64.0/19178.10.64.1 to 178.10.95.254178.10.95.2558,190
84178.10.96.0/19178.10.96.1 to 178.10.127.254178.10.127.2558,190
85178.10.128.0/19178.10.128.1 to 178.10.159.254178.10.159.2558,190
86178.10.160.0/19178.10.160.1 to 178.10.191.254178.10.191.2558,190
87178.10.192.0/19178.10.192.1 to 178.10.223.254178.10.223.2558,190
88178.10.224.0/19178.10.224.1 to 178.10.255.254178.10.255.2558,190
89178.11.0.0/19178.11.0.1 to 178.11.31.254178.11.31.2558,190
90178.11.32.0/19178.11.32.1 to 178.11.63.254178.11.63.2558,190
91178.11.64.0/19178.11.64.1 to 178.11.95.254178.11.95.2558,190
92178.11.96.0/19178.11.96.1 to 178.11.127.254178.11.127.2558,190
93178.11.128.0/19178.11.128.1 to 178.11.159.254178.11.159.2558,190
94178.11.160.0/19178.11.160.1 to 178.11.191.254178.11.191.2558,190
95178.11.192.0/19178.11.192.1 to 178.11.223.254178.11.223.2558,190
96178.11.224.0/19178.11.224.1 to 178.11.255.254178.11.255.2558,190
97178.12.0.0/19178.12.0.1 to 178.12.31.254178.12.31.2558,190
98178.12.32.0/19178.12.32.1 to 178.12.63.254178.12.63.2558,190
99178.12.64.0/19178.12.64.1 to 178.12.95.254178.12.95.2558,190
100178.12.96.0/19178.12.96.1 to 178.12.127.254178.12.127.2558,190
101178.12.128.0/19178.12.128.1 to 178.12.159.254178.12.159.2558,190
102178.12.160.0/19178.12.160.1 to 178.12.191.254178.12.191.2558,190
103178.12.192.0/19178.12.192.1 to 178.12.223.254178.12.223.2558,190
104178.12.224.0/19178.12.224.1 to 178.12.255.254178.12.255.2558,190
105178.13.0.0/19178.13.0.1 to 178.13.31.254178.13.31.2558,190
106178.13.32.0/19178.13.32.1 to 178.13.63.254178.13.63.2558,190
107178.13.64.0/19178.13.64.1 to 178.13.95.254178.13.95.2558,190
108178.13.96.0/19178.13.96.1 to 178.13.127.254178.13.127.2558,190
109178.13.128.0/19178.13.128.1 to 178.13.159.254178.13.159.2558,190
110178.13.160.0/19178.13.160.1 to 178.13.191.254178.13.191.2558,190
111178.13.192.0/19178.13.192.1 to 178.13.223.254178.13.223.2558,190
112178.13.224.0/19178.13.224.1 to 178.13.255.254178.13.255.2558,190
113178.14.0.0/19178.14.0.1 to 178.14.31.254178.14.31.2558,190
114178.14.32.0/19178.14.32.1 to 178.14.63.254178.14.63.2558,190
115178.14.64.0/19178.14.64.1 to 178.14.95.254178.14.95.2558,190
116178.14.96.0/19178.14.96.1 to 178.14.127.254178.14.127.2558,190
117178.14.128.0/19178.14.128.1 to 178.14.159.254178.14.159.2558,190
118178.14.160.0/19178.14.160.1 to 178.14.191.254178.14.191.2558,190
119178.14.192.0/19178.14.192.1 to 178.14.223.254178.14.223.2558,190
120178.14.224.0/19178.14.224.1 to 178.14.255.254178.14.255.2558,190
121178.15.0.0/19178.15.0.1 to 178.15.31.254178.15.31.2558,190
122178.15.32.0/19178.15.32.1 to 178.15.63.254178.15.63.2558,190
123178.15.64.0/19178.15.64.1 to 178.15.95.254178.15.95.2558,190
124178.15.96.0/19178.15.96.1 to 178.15.127.254178.15.127.2558,190
125178.15.128.0/19178.15.128.1 to 178.15.159.254178.15.159.2558,190
126178.15.160.0/19178.15.160.1 to 178.15.191.254178.15.191.2558,190
127178.15.192.0/19178.15.192.1 to 178.15.223.254178.15.223.2558,190
128178.15.224.0/19178.15.224.1 to 178.15.255.254178.15.255.2558,190
129178.16.0.0/19178.16.0.1 to 178.16.31.254178.16.31.2558,190
130178.16.32.0/19178.16.32.1 to 178.16.63.254178.16.63.2558,190
131178.16.64.0/19178.16.64.1 to 178.16.95.254178.16.95.2558,190
132178.16.96.0/19178.16.96.1 to 178.16.127.254178.16.127.2558,190
133178.16.128.0/19178.16.128.1 to 178.16.159.254178.16.159.2558,190
134178.16.160.0/19178.16.160.1 to 178.16.191.254178.16.191.2558,190
135178.16.192.0/19178.16.192.1 to 178.16.223.254178.16.223.2558,190
136178.16.224.0/19178.16.224.1 to 178.16.255.254178.16.255.2558,190
137178.17.0.0/19178.17.0.1 to 178.17.31.254178.17.31.2558,190
138178.17.32.0/19178.17.32.1 to 178.17.63.254178.17.63.2558,190
139178.17.64.0/19178.17.64.1 to 178.17.95.254178.17.95.2558,190
140178.17.96.0/19178.17.96.1 to 178.17.127.254178.17.127.2558,190
141178.17.128.0/19178.17.128.1 to 178.17.159.254178.17.159.2558,190
142178.17.160.0/19178.17.160.1 to 178.17.191.254178.17.191.2558,190
143178.17.192.0/19178.17.192.1 to 178.17.223.254178.17.223.2558,190
144178.17.224.0/19178.17.224.1 to 178.17.255.254178.17.255.2558,190
145178.18.0.0/19178.18.0.1 to 178.18.31.254178.18.31.2558,190
146178.18.32.0/19178.18.32.1 to 178.18.63.254178.18.63.2558,190
147178.18.64.0/19178.18.64.1 to 178.18.95.254178.18.95.2558,190
148178.18.96.0/19178.18.96.1 to 178.18.127.254178.18.127.2558,190
149178.18.128.0/19178.18.128.1 to 178.18.159.254178.18.159.2558,190
150178.18.160.0/19178.18.160.1 to 178.18.191.254178.18.191.2558,190
151178.18.192.0/19178.18.192.1 to 178.18.223.254178.18.223.2558,190
152178.18.224.0/19178.18.224.1 to 178.18.255.254178.18.255.2558,190
153178.19.0.0/19178.19.0.1 to 178.19.31.254178.19.31.2558,190
154178.19.32.0/19178.19.32.1 to 178.19.63.254178.19.63.2558,190
155178.19.64.0/19178.19.64.1 to 178.19.95.254178.19.95.2558,190
156178.19.96.0/19178.19.96.1 to 178.19.127.254178.19.127.2558,190
157178.19.128.0/19178.19.128.1 to 178.19.159.254178.19.159.2558,190
158178.19.160.0/19178.19.160.1 to 178.19.191.254178.19.191.2558,190
159178.19.192.0/19178.19.192.1 to 178.19.223.254178.19.223.2558,190
160178.19.224.0/19178.19.224.1 to 178.19.255.254178.19.255.2558,190
161178.20.0.0/19178.20.0.1 to 178.20.31.254178.20.31.2558,190
162178.20.32.0/19178.20.32.1 to 178.20.63.254178.20.63.2558,190
163178.20.64.0/19178.20.64.1 to 178.20.95.254178.20.95.2558,190
164178.20.96.0/19178.20.96.1 to 178.20.127.254178.20.127.2558,190
165178.20.128.0/19178.20.128.1 to 178.20.159.254178.20.159.2558,190
166178.20.160.0/19178.20.160.1 to 178.20.191.254178.20.191.2558,190
167178.20.192.0/19178.20.192.1 to 178.20.223.254178.20.223.2558,190
168178.20.224.0/19178.20.224.1 to 178.20.255.254178.20.255.2558,190
169178.21.0.0/19178.21.0.1 to 178.21.31.254178.21.31.2558,190
170178.21.32.0/19178.21.32.1 to 178.21.63.254178.21.63.2558,190
171178.21.64.0/19178.21.64.1 to 178.21.95.254178.21.95.2558,190
172178.21.96.0/19178.21.96.1 to 178.21.127.254178.21.127.2558,190
173178.21.128.0/19178.21.128.1 to 178.21.159.254178.21.159.2558,190
174178.21.160.0/19178.21.160.1 to 178.21.191.254178.21.191.2558,190
175178.21.192.0/19178.21.192.1 to 178.21.223.254178.21.223.2558,190
176178.21.224.0/19178.21.224.1 to 178.21.255.254178.21.255.2558,190
177178.22.0.0/19178.22.0.1 to 178.22.31.254178.22.31.2558,190
178178.22.32.0/19178.22.32.1 to 178.22.63.254178.22.63.2558,190
179178.22.64.0/19178.22.64.1 to 178.22.95.254178.22.95.2558,190
180178.22.96.0/19178.22.96.1 to 178.22.127.254178.22.127.2558,190
181178.22.128.0/19178.22.128.1 to 178.22.159.254178.22.159.2558,190
182178.22.160.0/19178.22.160.1 to 178.22.191.254178.22.191.2558,190
183178.22.192.0/19178.22.192.1 to 178.22.223.254178.22.223.2558,190
184178.22.224.0/19178.22.224.1 to 178.22.255.254178.22.255.2558,190
185178.23.0.0/19178.23.0.1 to 178.23.31.254178.23.31.2558,190
186178.23.32.0/19178.23.32.1 to 178.23.63.254178.23.63.2558,190
187178.23.64.0/19178.23.64.1 to 178.23.95.254178.23.95.2558,190
188178.23.96.0/19178.23.96.1 to 178.23.127.254178.23.127.2558,190
189178.23.128.0/19178.23.128.1 to 178.23.159.254178.23.159.2558,190
190178.23.160.0/19178.23.160.1 to 178.23.191.254178.23.191.2558,190
191178.23.192.0/19178.23.192.1 to 178.23.223.254178.23.223.2558,190
192178.23.224.0/19178.23.224.1 to 178.23.255.254178.23.255.2558,190
193178.24.0.0/19178.24.0.1 to 178.24.31.254178.24.31.2558,190
194178.24.32.0/19178.24.32.1 to 178.24.63.254178.24.63.2558,190
195178.24.64.0/19178.24.64.1 to 178.24.95.254178.24.95.2558,190
196178.24.96.0/19178.24.96.1 to 178.24.127.254178.24.127.2558,190
197178.24.128.0/19178.24.128.1 to 178.24.159.254178.24.159.2558,190
198178.24.160.0/19178.24.160.1 to 178.24.191.254178.24.191.2558,190
199178.24.192.0/19178.24.192.1 to 178.24.223.254178.24.223.2558,190
200178.24.224.0/19178.24.224.1 to 178.24.255.254178.24.255.2558,190
201178.25.0.0/19178.25.0.1 to 178.25.31.254178.25.31.2558,190
202178.25.32.0/19178.25.32.1 to 178.25.63.254178.25.63.2558,190
203178.25.64.0/19178.25.64.1 to 178.25.95.254178.25.95.2558,190
204178.25.96.0/19178.25.96.1 to 178.25.127.254178.25.127.2558,190
205178.25.128.0/19178.25.128.1 to 178.25.159.254178.25.159.2558,190
206178.25.160.0/19178.25.160.1 to 178.25.191.254178.25.191.2558,190
207178.25.192.0/19178.25.192.1 to 178.25.223.254178.25.223.2558,190
208178.25.224.0/19178.25.224.1 to 178.25.255.254178.25.255.2558,190
209178.26.0.0/19178.26.0.1 to 178.26.31.254178.26.31.2558,190
210178.26.32.0/19178.26.32.1 to 178.26.63.254178.26.63.2558,190
211178.26.64.0/19178.26.64.1 to 178.26.95.254178.26.95.2558,190
212178.26.96.0/19178.26.96.1 to 178.26.127.254178.26.127.2558,190
213178.26.128.0/19178.26.128.1 to 178.26.159.254178.26.159.2558,190
214178.26.160.0/19178.26.160.1 to 178.26.191.254178.26.191.2558,190
215178.26.192.0/19178.26.192.1 to 178.26.223.254178.26.223.2558,190
216178.26.224.0/19178.26.224.1 to 178.26.255.254178.26.255.2558,190
217178.27.0.0/19178.27.0.1 to 178.27.31.254178.27.31.2558,190
218178.27.32.0/19178.27.32.1 to 178.27.63.254178.27.63.2558,190
219178.27.64.0/19178.27.64.1 to 178.27.95.254178.27.95.2558,190
220178.27.96.0/19178.27.96.1 to 178.27.127.254178.27.127.2558,190
221178.27.128.0/19178.27.128.1 to 178.27.159.254178.27.159.2558,190
222178.27.160.0/19178.27.160.1 to 178.27.191.254178.27.191.2558,190
223178.27.192.0/19178.27.192.1 to 178.27.223.254178.27.223.2558,190
224178.27.224.0/19178.27.224.1 to 178.27.255.254178.27.255.2558,190
225178.28.0.0/19178.28.0.1 to 178.28.31.254178.28.31.2558,190
226178.28.32.0/19178.28.32.1 to 178.28.63.254178.28.63.2558,190
227178.28.64.0/19178.28.64.1 to 178.28.95.254178.28.95.2558,190
228178.28.96.0/19178.28.96.1 to 178.28.127.254178.28.127.2558,190
229178.28.128.0/19178.28.128.1 to 178.28.159.254178.28.159.2558,190
230178.28.160.0/19178.28.160.1 to 178.28.191.254178.28.191.2558,190
231178.28.192.0/19178.28.192.1 to 178.28.223.254178.28.223.2558,190
232178.28.224.0/19178.28.224.1 to 178.28.255.254178.28.255.2558,190
233178.29.0.0/19178.29.0.1 to 178.29.31.254178.29.31.2558,190
234178.29.32.0/19178.29.32.1 to 178.29.63.254178.29.63.2558,190
235178.29.64.0/19178.29.64.1 to 178.29.95.254178.29.95.2558,190
236178.29.96.0/19178.29.96.1 to 178.29.127.254178.29.127.2558,190
237178.29.128.0/19178.29.128.1 to 178.29.159.254178.29.159.2558,190
238178.29.160.0/19178.29.160.1 to 178.29.191.254178.29.191.2558,190
239178.29.192.0/19178.29.192.1 to 178.29.223.254178.29.223.2558,190
240178.29.224.0/19178.29.224.1 to 178.29.255.254178.29.255.2558,190
241178.30.0.0/19178.30.0.1 to 178.30.31.254178.30.31.2558,190
242178.30.32.0/19178.30.32.1 to 178.30.63.254178.30.63.2558,190
243178.30.64.0/19178.30.64.1 to 178.30.95.254178.30.95.2558,190
244178.30.96.0/19178.30.96.1 to 178.30.127.254178.30.127.2558,190
245178.30.128.0/19178.30.128.1 to 178.30.159.254178.30.159.2558,190
246178.30.160.0/19178.30.160.1 to 178.30.191.254178.30.191.2558,190
247178.30.192.0/19178.30.192.1 to 178.30.223.254178.30.223.2558,190
248178.30.224.0/19178.30.224.1 to 178.30.255.254178.30.255.2558,190
249178.31.0.0/19178.31.0.1 to 178.31.31.254178.31.31.2558,190
250178.31.32.0/19178.31.32.1 to 178.31.63.254178.31.63.2558,190
251178.31.64.0/19178.31.64.1 to 178.31.95.254178.31.95.2558,190
252178.31.96.0/19178.31.96.1 to 178.31.127.254178.31.127.2558,190
253178.31.128.0/19178.31.128.1 to 178.31.159.254178.31.159.2558,190
254178.31.160.0/19178.31.160.1 to 178.31.191.254178.31.191.2558,190
255178.31.192.0/19178.31.192.1 to 178.31.223.254178.31.223.2558,190
256178.31.224.0/19178.31.224.1 to 178.31.255.254178.31.255.2558,190

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.