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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.

Network178.0.0.0/7
Usable hosts33,554,430
Subnet mask254.0.0.0
Addresses33,554,432
Network address
178.0.0.0
Broadcast address
179.255.255.255
First usable
178.0.0.1
Last usable
179.255.255.254
Usable hosts
33,554,430 (33,554,432 less the network and broadcast addresses)
Subnet mask
254.0.0.0
Wildcard mask
1.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/7
Type
Public public
Old class
B (default /16)
As numbers
Hex B2000000 · Integer 2986344448 to 3019898879
Reverse DNS zones
178.in-addr.arpa
179.in-addr.arpa
/7 is not on a 8-bit boundary, so it takes 2 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10110010.00000000.00000000.00000000178.0.0.0
Subnet mask11111110.00000000.00000000.00000000254.0.0.0
Network10110010.00000000.00000000.00000000178.0.0.0
Broadcast10110011.11111111.11111111.11111111179.255.255.255
Split into smaller subnets/18
/8 (2)/9 (4)/10 (8)/11 (16)/12 (32)/13 (64)/14 (128)/15 (256)/16 (512)/17 (1,024)/18 (2,048)/19 (4,096)

178.0.0.0/7 makes 2,048 subnets of /18; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1178.0.0.0/18178.0.0.1 to 178.0.63.254178.0.63.25516,382
2178.0.64.0/18178.0.64.1 to 178.0.127.254178.0.127.25516,382
3178.0.128.0/18178.0.128.1 to 178.0.191.254178.0.191.25516,382
4178.0.192.0/18178.0.192.1 to 178.0.255.254178.0.255.25516,382
5178.1.0.0/18178.1.0.1 to 178.1.63.254178.1.63.25516,382
6178.1.64.0/18178.1.64.1 to 178.1.127.254178.1.127.25516,382
7178.1.128.0/18178.1.128.1 to 178.1.191.254178.1.191.25516,382
8178.1.192.0/18178.1.192.1 to 178.1.255.254178.1.255.25516,382
9178.2.0.0/18178.2.0.1 to 178.2.63.254178.2.63.25516,382
10178.2.64.0/18178.2.64.1 to 178.2.127.254178.2.127.25516,382
11178.2.128.0/18178.2.128.1 to 178.2.191.254178.2.191.25516,382
12178.2.192.0/18178.2.192.1 to 178.2.255.254178.2.255.25516,382
13178.3.0.0/18178.3.0.1 to 178.3.63.254178.3.63.25516,382
14178.3.64.0/18178.3.64.1 to 178.3.127.254178.3.127.25516,382
15178.3.128.0/18178.3.128.1 to 178.3.191.254178.3.191.25516,382
16178.3.192.0/18178.3.192.1 to 178.3.255.254178.3.255.25516,382
17178.4.0.0/18178.4.0.1 to 178.4.63.254178.4.63.25516,382
18178.4.64.0/18178.4.64.1 to 178.4.127.254178.4.127.25516,382
19178.4.128.0/18178.4.128.1 to 178.4.191.254178.4.191.25516,382
20178.4.192.0/18178.4.192.1 to 178.4.255.254178.4.255.25516,382
21178.5.0.0/18178.5.0.1 to 178.5.63.254178.5.63.25516,382
22178.5.64.0/18178.5.64.1 to 178.5.127.254178.5.127.25516,382
23178.5.128.0/18178.5.128.1 to 178.5.191.254178.5.191.25516,382
24178.5.192.0/18178.5.192.1 to 178.5.255.254178.5.255.25516,382
25178.6.0.0/18178.6.0.1 to 178.6.63.254178.6.63.25516,382
26178.6.64.0/18178.6.64.1 to 178.6.127.254178.6.127.25516,382
27178.6.128.0/18178.6.128.1 to 178.6.191.254178.6.191.25516,382
28178.6.192.0/18178.6.192.1 to 178.6.255.254178.6.255.25516,382
29178.7.0.0/18178.7.0.1 to 178.7.63.254178.7.63.25516,382
30178.7.64.0/18178.7.64.1 to 178.7.127.254178.7.127.25516,382
31178.7.128.0/18178.7.128.1 to 178.7.191.254178.7.191.25516,382
32178.7.192.0/18178.7.192.1 to 178.7.255.254178.7.255.25516,382
33178.8.0.0/18178.8.0.1 to 178.8.63.254178.8.63.25516,382
34178.8.64.0/18178.8.64.1 to 178.8.127.254178.8.127.25516,382
35178.8.128.0/18178.8.128.1 to 178.8.191.254178.8.191.25516,382
36178.8.192.0/18178.8.192.1 to 178.8.255.254178.8.255.25516,382
37178.9.0.0/18178.9.0.1 to 178.9.63.254178.9.63.25516,382
38178.9.64.0/18178.9.64.1 to 178.9.127.254178.9.127.25516,382
39178.9.128.0/18178.9.128.1 to 178.9.191.254178.9.191.25516,382
40178.9.192.0/18178.9.192.1 to 178.9.255.254178.9.255.25516,382
41178.10.0.0/18178.10.0.1 to 178.10.63.254178.10.63.25516,382
42178.10.64.0/18178.10.64.1 to 178.10.127.254178.10.127.25516,382
43178.10.128.0/18178.10.128.1 to 178.10.191.254178.10.191.25516,382
44178.10.192.0/18178.10.192.1 to 178.10.255.254178.10.255.25516,382
45178.11.0.0/18178.11.0.1 to 178.11.63.254178.11.63.25516,382
46178.11.64.0/18178.11.64.1 to 178.11.127.254178.11.127.25516,382
47178.11.128.0/18178.11.128.1 to 178.11.191.254178.11.191.25516,382
48178.11.192.0/18178.11.192.1 to 178.11.255.254178.11.255.25516,382
49178.12.0.0/18178.12.0.1 to 178.12.63.254178.12.63.25516,382
50178.12.64.0/18178.12.64.1 to 178.12.127.254178.12.127.25516,382
51178.12.128.0/18178.12.128.1 to 178.12.191.254178.12.191.25516,382
52178.12.192.0/18178.12.192.1 to 178.12.255.254178.12.255.25516,382
53178.13.0.0/18178.13.0.1 to 178.13.63.254178.13.63.25516,382
54178.13.64.0/18178.13.64.1 to 178.13.127.254178.13.127.25516,382
55178.13.128.0/18178.13.128.1 to 178.13.191.254178.13.191.25516,382
56178.13.192.0/18178.13.192.1 to 178.13.255.254178.13.255.25516,382
57178.14.0.0/18178.14.0.1 to 178.14.63.254178.14.63.25516,382
58178.14.64.0/18178.14.64.1 to 178.14.127.254178.14.127.25516,382
59178.14.128.0/18178.14.128.1 to 178.14.191.254178.14.191.25516,382
60178.14.192.0/18178.14.192.1 to 178.14.255.254178.14.255.25516,382
61178.15.0.0/18178.15.0.1 to 178.15.63.254178.15.63.25516,382
62178.15.64.0/18178.15.64.1 to 178.15.127.254178.15.127.25516,382
63178.15.128.0/18178.15.128.1 to 178.15.191.254178.15.191.25516,382
64178.15.192.0/18178.15.192.1 to 178.15.255.254178.15.255.25516,382
65178.16.0.0/18178.16.0.1 to 178.16.63.254178.16.63.25516,382
66178.16.64.0/18178.16.64.1 to 178.16.127.254178.16.127.25516,382
67178.16.128.0/18178.16.128.1 to 178.16.191.254178.16.191.25516,382
68178.16.192.0/18178.16.192.1 to 178.16.255.254178.16.255.25516,382
69178.17.0.0/18178.17.0.1 to 178.17.63.254178.17.63.25516,382
70178.17.64.0/18178.17.64.1 to 178.17.127.254178.17.127.25516,382
71178.17.128.0/18178.17.128.1 to 178.17.191.254178.17.191.25516,382
72178.17.192.0/18178.17.192.1 to 178.17.255.254178.17.255.25516,382
73178.18.0.0/18178.18.0.1 to 178.18.63.254178.18.63.25516,382
74178.18.64.0/18178.18.64.1 to 178.18.127.254178.18.127.25516,382
75178.18.128.0/18178.18.128.1 to 178.18.191.254178.18.191.25516,382
76178.18.192.0/18178.18.192.1 to 178.18.255.254178.18.255.25516,382
77178.19.0.0/18178.19.0.1 to 178.19.63.254178.19.63.25516,382
78178.19.64.0/18178.19.64.1 to 178.19.127.254178.19.127.25516,382
79178.19.128.0/18178.19.128.1 to 178.19.191.254178.19.191.25516,382
80178.19.192.0/18178.19.192.1 to 178.19.255.254178.19.255.25516,382
81178.20.0.0/18178.20.0.1 to 178.20.63.254178.20.63.25516,382
82178.20.64.0/18178.20.64.1 to 178.20.127.254178.20.127.25516,382
83178.20.128.0/18178.20.128.1 to 178.20.191.254178.20.191.25516,382
84178.20.192.0/18178.20.192.1 to 178.20.255.254178.20.255.25516,382
85178.21.0.0/18178.21.0.1 to 178.21.63.254178.21.63.25516,382
86178.21.64.0/18178.21.64.1 to 178.21.127.254178.21.127.25516,382
87178.21.128.0/18178.21.128.1 to 178.21.191.254178.21.191.25516,382
88178.21.192.0/18178.21.192.1 to 178.21.255.254178.21.255.25516,382
89178.22.0.0/18178.22.0.1 to 178.22.63.254178.22.63.25516,382
90178.22.64.0/18178.22.64.1 to 178.22.127.254178.22.127.25516,382
91178.22.128.0/18178.22.128.1 to 178.22.191.254178.22.191.25516,382
92178.22.192.0/18178.22.192.1 to 178.22.255.254178.22.255.25516,382
93178.23.0.0/18178.23.0.1 to 178.23.63.254178.23.63.25516,382
94178.23.64.0/18178.23.64.1 to 178.23.127.254178.23.127.25516,382
95178.23.128.0/18178.23.128.1 to 178.23.191.254178.23.191.25516,382
96178.23.192.0/18178.23.192.1 to 178.23.255.254178.23.255.25516,382
97178.24.0.0/18178.24.0.1 to 178.24.63.254178.24.63.25516,382
98178.24.64.0/18178.24.64.1 to 178.24.127.254178.24.127.25516,382
99178.24.128.0/18178.24.128.1 to 178.24.191.254178.24.191.25516,382
100178.24.192.0/18178.24.192.1 to 178.24.255.254178.24.255.25516,382
101178.25.0.0/18178.25.0.1 to 178.25.63.254178.25.63.25516,382
102178.25.64.0/18178.25.64.1 to 178.25.127.254178.25.127.25516,382
103178.25.128.0/18178.25.128.1 to 178.25.191.254178.25.191.25516,382
104178.25.192.0/18178.25.192.1 to 178.25.255.254178.25.255.25516,382
105178.26.0.0/18178.26.0.1 to 178.26.63.254178.26.63.25516,382
106178.26.64.0/18178.26.64.1 to 178.26.127.254178.26.127.25516,382
107178.26.128.0/18178.26.128.1 to 178.26.191.254178.26.191.25516,382
108178.26.192.0/18178.26.192.1 to 178.26.255.254178.26.255.25516,382
109178.27.0.0/18178.27.0.1 to 178.27.63.254178.27.63.25516,382
110178.27.64.0/18178.27.64.1 to 178.27.127.254178.27.127.25516,382
111178.27.128.0/18178.27.128.1 to 178.27.191.254178.27.191.25516,382
112178.27.192.0/18178.27.192.1 to 178.27.255.254178.27.255.25516,382
113178.28.0.0/18178.28.0.1 to 178.28.63.254178.28.63.25516,382
114178.28.64.0/18178.28.64.1 to 178.28.127.254178.28.127.25516,382
115178.28.128.0/18178.28.128.1 to 178.28.191.254178.28.191.25516,382
116178.28.192.0/18178.28.192.1 to 178.28.255.254178.28.255.25516,382
117178.29.0.0/18178.29.0.1 to 178.29.63.254178.29.63.25516,382
118178.29.64.0/18178.29.64.1 to 178.29.127.254178.29.127.25516,382
119178.29.128.0/18178.29.128.1 to 178.29.191.254178.29.191.25516,382
120178.29.192.0/18178.29.192.1 to 178.29.255.254178.29.255.25516,382
121178.30.0.0/18178.30.0.1 to 178.30.63.254178.30.63.25516,382
122178.30.64.0/18178.30.64.1 to 178.30.127.254178.30.127.25516,382
123178.30.128.0/18178.30.128.1 to 178.30.191.254178.30.191.25516,382
124178.30.192.0/18178.30.192.1 to 178.30.255.254178.30.255.25516,382
125178.31.0.0/18178.31.0.1 to 178.31.63.254178.31.63.25516,382
126178.31.64.0/18178.31.64.1 to 178.31.127.254178.31.127.25516,382
127178.31.128.0/18178.31.128.1 to 178.31.191.254178.31.191.25516,382
128178.31.192.0/18178.31.192.1 to 178.31.255.254178.31.255.25516,382
129178.32.0.0/18178.32.0.1 to 178.32.63.254178.32.63.25516,382
130178.32.64.0/18178.32.64.1 to 178.32.127.254178.32.127.25516,382
131178.32.128.0/18178.32.128.1 to 178.32.191.254178.32.191.25516,382
132178.32.192.0/18178.32.192.1 to 178.32.255.254178.32.255.25516,382
133178.33.0.0/18178.33.0.1 to 178.33.63.254178.33.63.25516,382
134178.33.64.0/18178.33.64.1 to 178.33.127.254178.33.127.25516,382
135178.33.128.0/18178.33.128.1 to 178.33.191.254178.33.191.25516,382
136178.33.192.0/18178.33.192.1 to 178.33.255.254178.33.255.25516,382
137178.34.0.0/18178.34.0.1 to 178.34.63.254178.34.63.25516,382
138178.34.64.0/18178.34.64.1 to 178.34.127.254178.34.127.25516,382
139178.34.128.0/18178.34.128.1 to 178.34.191.254178.34.191.25516,382
140178.34.192.0/18178.34.192.1 to 178.34.255.254178.34.255.25516,382
141178.35.0.0/18178.35.0.1 to 178.35.63.254178.35.63.25516,382
142178.35.64.0/18178.35.64.1 to 178.35.127.254178.35.127.25516,382
143178.35.128.0/18178.35.128.1 to 178.35.191.254178.35.191.25516,382
144178.35.192.0/18178.35.192.1 to 178.35.255.254178.35.255.25516,382
145178.36.0.0/18178.36.0.1 to 178.36.63.254178.36.63.25516,382
146178.36.64.0/18178.36.64.1 to 178.36.127.254178.36.127.25516,382
147178.36.128.0/18178.36.128.1 to 178.36.191.254178.36.191.25516,382
148178.36.192.0/18178.36.192.1 to 178.36.255.254178.36.255.25516,382
149178.37.0.0/18178.37.0.1 to 178.37.63.254178.37.63.25516,382
150178.37.64.0/18178.37.64.1 to 178.37.127.254178.37.127.25516,382
151178.37.128.0/18178.37.128.1 to 178.37.191.254178.37.191.25516,382
152178.37.192.0/18178.37.192.1 to 178.37.255.254178.37.255.25516,382
153178.38.0.0/18178.38.0.1 to 178.38.63.254178.38.63.25516,382
154178.38.64.0/18178.38.64.1 to 178.38.127.254178.38.127.25516,382
155178.38.128.0/18178.38.128.1 to 178.38.191.254178.38.191.25516,382
156178.38.192.0/18178.38.192.1 to 178.38.255.254178.38.255.25516,382
157178.39.0.0/18178.39.0.1 to 178.39.63.254178.39.63.25516,382
158178.39.64.0/18178.39.64.1 to 178.39.127.254178.39.127.25516,382
159178.39.128.0/18178.39.128.1 to 178.39.191.254178.39.191.25516,382
160178.39.192.0/18178.39.192.1 to 178.39.255.254178.39.255.25516,382
161178.40.0.0/18178.40.0.1 to 178.40.63.254178.40.63.25516,382
162178.40.64.0/18178.40.64.1 to 178.40.127.254178.40.127.25516,382
163178.40.128.0/18178.40.128.1 to 178.40.191.254178.40.191.25516,382
164178.40.192.0/18178.40.192.1 to 178.40.255.254178.40.255.25516,382
165178.41.0.0/18178.41.0.1 to 178.41.63.254178.41.63.25516,382
166178.41.64.0/18178.41.64.1 to 178.41.127.254178.41.127.25516,382
167178.41.128.0/18178.41.128.1 to 178.41.191.254178.41.191.25516,382
168178.41.192.0/18178.41.192.1 to 178.41.255.254178.41.255.25516,382
169178.42.0.0/18178.42.0.1 to 178.42.63.254178.42.63.25516,382
170178.42.64.0/18178.42.64.1 to 178.42.127.254178.42.127.25516,382
171178.42.128.0/18178.42.128.1 to 178.42.191.254178.42.191.25516,382
172178.42.192.0/18178.42.192.1 to 178.42.255.254178.42.255.25516,382
173178.43.0.0/18178.43.0.1 to 178.43.63.254178.43.63.25516,382
174178.43.64.0/18178.43.64.1 to 178.43.127.254178.43.127.25516,382
175178.43.128.0/18178.43.128.1 to 178.43.191.254178.43.191.25516,382
176178.43.192.0/18178.43.192.1 to 178.43.255.254178.43.255.25516,382
177178.44.0.0/18178.44.0.1 to 178.44.63.254178.44.63.25516,382
178178.44.64.0/18178.44.64.1 to 178.44.127.254178.44.127.25516,382
179178.44.128.0/18178.44.128.1 to 178.44.191.254178.44.191.25516,382
180178.44.192.0/18178.44.192.1 to 178.44.255.254178.44.255.25516,382
181178.45.0.0/18178.45.0.1 to 178.45.63.254178.45.63.25516,382
182178.45.64.0/18178.45.64.1 to 178.45.127.254178.45.127.25516,382
183178.45.128.0/18178.45.128.1 to 178.45.191.254178.45.191.25516,382
184178.45.192.0/18178.45.192.1 to 178.45.255.254178.45.255.25516,382
185178.46.0.0/18178.46.0.1 to 178.46.63.254178.46.63.25516,382
186178.46.64.0/18178.46.64.1 to 178.46.127.254178.46.127.25516,382
187178.46.128.0/18178.46.128.1 to 178.46.191.254178.46.191.25516,382
188178.46.192.0/18178.46.192.1 to 178.46.255.254178.46.255.25516,382
189178.47.0.0/18178.47.0.1 to 178.47.63.254178.47.63.25516,382
190178.47.64.0/18178.47.64.1 to 178.47.127.254178.47.127.25516,382
191178.47.128.0/18178.47.128.1 to 178.47.191.254178.47.191.25516,382
192178.47.192.0/18178.47.192.1 to 178.47.255.254178.47.255.25516,382
193178.48.0.0/18178.48.0.1 to 178.48.63.254178.48.63.25516,382
194178.48.64.0/18178.48.64.1 to 178.48.127.254178.48.127.25516,382
195178.48.128.0/18178.48.128.1 to 178.48.191.254178.48.191.25516,382
196178.48.192.0/18178.48.192.1 to 178.48.255.254178.48.255.25516,382
197178.49.0.0/18178.49.0.1 to 178.49.63.254178.49.63.25516,382
198178.49.64.0/18178.49.64.1 to 178.49.127.254178.49.127.25516,382
199178.49.128.0/18178.49.128.1 to 178.49.191.254178.49.191.25516,382
200178.49.192.0/18178.49.192.1 to 178.49.255.254178.49.255.25516,382
201178.50.0.0/18178.50.0.1 to 178.50.63.254178.50.63.25516,382
202178.50.64.0/18178.50.64.1 to 178.50.127.254178.50.127.25516,382
203178.50.128.0/18178.50.128.1 to 178.50.191.254178.50.191.25516,382
204178.50.192.0/18178.50.192.1 to 178.50.255.254178.50.255.25516,382
205178.51.0.0/18178.51.0.1 to 178.51.63.254178.51.63.25516,382
206178.51.64.0/18178.51.64.1 to 178.51.127.254178.51.127.25516,382
207178.51.128.0/18178.51.128.1 to 178.51.191.254178.51.191.25516,382
208178.51.192.0/18178.51.192.1 to 178.51.255.254178.51.255.25516,382
209178.52.0.0/18178.52.0.1 to 178.52.63.254178.52.63.25516,382
210178.52.64.0/18178.52.64.1 to 178.52.127.254178.52.127.25516,382
211178.52.128.0/18178.52.128.1 to 178.52.191.254178.52.191.25516,382
212178.52.192.0/18178.52.192.1 to 178.52.255.254178.52.255.25516,382
213178.53.0.0/18178.53.0.1 to 178.53.63.254178.53.63.25516,382
214178.53.64.0/18178.53.64.1 to 178.53.127.254178.53.127.25516,382
215178.53.128.0/18178.53.128.1 to 178.53.191.254178.53.191.25516,382
216178.53.192.0/18178.53.192.1 to 178.53.255.254178.53.255.25516,382
217178.54.0.0/18178.54.0.1 to 178.54.63.254178.54.63.25516,382
218178.54.64.0/18178.54.64.1 to 178.54.127.254178.54.127.25516,382
219178.54.128.0/18178.54.128.1 to 178.54.191.254178.54.191.25516,382
220178.54.192.0/18178.54.192.1 to 178.54.255.254178.54.255.25516,382
221178.55.0.0/18178.55.0.1 to 178.55.63.254178.55.63.25516,382
222178.55.64.0/18178.55.64.1 to 178.55.127.254178.55.127.25516,382
223178.55.128.0/18178.55.128.1 to 178.55.191.254178.55.191.25516,382
224178.55.192.0/18178.55.192.1 to 178.55.255.254178.55.255.25516,382
225178.56.0.0/18178.56.0.1 to 178.56.63.254178.56.63.25516,382
226178.56.64.0/18178.56.64.1 to 178.56.127.254178.56.127.25516,382
227178.56.128.0/18178.56.128.1 to 178.56.191.254178.56.191.25516,382
228178.56.192.0/18178.56.192.1 to 178.56.255.254178.56.255.25516,382
229178.57.0.0/18178.57.0.1 to 178.57.63.254178.57.63.25516,382
230178.57.64.0/18178.57.64.1 to 178.57.127.254178.57.127.25516,382
231178.57.128.0/18178.57.128.1 to 178.57.191.254178.57.191.25516,382
232178.57.192.0/18178.57.192.1 to 178.57.255.254178.57.255.25516,382
233178.58.0.0/18178.58.0.1 to 178.58.63.254178.58.63.25516,382
234178.58.64.0/18178.58.64.1 to 178.58.127.254178.58.127.25516,382
235178.58.128.0/18178.58.128.1 to 178.58.191.254178.58.191.25516,382
236178.58.192.0/18178.58.192.1 to 178.58.255.254178.58.255.25516,382
237178.59.0.0/18178.59.0.1 to 178.59.63.254178.59.63.25516,382
238178.59.64.0/18178.59.64.1 to 178.59.127.254178.59.127.25516,382
239178.59.128.0/18178.59.128.1 to 178.59.191.254178.59.191.25516,382
240178.59.192.0/18178.59.192.1 to 178.59.255.254178.59.255.25516,382
241178.60.0.0/18178.60.0.1 to 178.60.63.254178.60.63.25516,382
242178.60.64.0/18178.60.64.1 to 178.60.127.254178.60.127.25516,382
243178.60.128.0/18178.60.128.1 to 178.60.191.254178.60.191.25516,382
244178.60.192.0/18178.60.192.1 to 178.60.255.254178.60.255.25516,382
245178.61.0.0/18178.61.0.1 to 178.61.63.254178.61.63.25516,382
246178.61.64.0/18178.61.64.1 to 178.61.127.254178.61.127.25516,382
247178.61.128.0/18178.61.128.1 to 178.61.191.254178.61.191.25516,382
248178.61.192.0/18178.61.192.1 to 178.61.255.254178.61.255.25516,382
249178.62.0.0/18178.62.0.1 to 178.62.63.254178.62.63.25516,382
250178.62.64.0/18178.62.64.1 to 178.62.127.254178.62.127.25516,382
251178.62.128.0/18178.62.128.1 to 178.62.191.254178.62.191.25516,382
252178.62.192.0/18178.62.192.1 to 178.62.255.254178.62.255.25516,382
253178.63.0.0/18178.63.0.1 to 178.63.63.254178.63.63.25516,382
254178.63.64.0/18178.63.64.1 to 178.63.127.254178.63.127.25516,382
255178.63.128.0/18178.63.128.1 to 178.63.191.254178.63.191.25516,382
256178.63.192.0/18178.63.192.1 to 178.63.255.254178.63.255.25516,382

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.