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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.

Network120.0.0.0/7
Usable hosts33,554,430
Subnet mask254.0.0.0
Addresses33,554,432
Network address
120.0.0.0
Broadcast address
121.255.255.255
First usable
120.0.0.1
Last usable
121.255.255.254
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
A (default /8)
As numbers
Hex 78000000 · Integer 2013265920 to 2046820351
Reverse DNS zones
120.in-addr.arpa
121.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
Address01111000.00000000.00000000.00000000120.0.0.0
Subnet mask11111110.00000000.00000000.00000000254.0.0.0
Network01111000.00000000.00000000.00000000120.0.0.0
Broadcast01111001.11111111.11111111.11111111121.255.255.255
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)

120.0.0.0/7 makes 2,048 subnets of /18; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1120.0.0.0/18120.0.0.1 to 120.0.63.254120.0.63.25516,382
2120.0.64.0/18120.0.64.1 to 120.0.127.254120.0.127.25516,382
3120.0.128.0/18120.0.128.1 to 120.0.191.254120.0.191.25516,382
4120.0.192.0/18120.0.192.1 to 120.0.255.254120.0.255.25516,382
5120.1.0.0/18120.1.0.1 to 120.1.63.254120.1.63.25516,382
6120.1.64.0/18120.1.64.1 to 120.1.127.254120.1.127.25516,382
7120.1.128.0/18120.1.128.1 to 120.1.191.254120.1.191.25516,382
8120.1.192.0/18120.1.192.1 to 120.1.255.254120.1.255.25516,382
9120.2.0.0/18120.2.0.1 to 120.2.63.254120.2.63.25516,382
10120.2.64.0/18120.2.64.1 to 120.2.127.254120.2.127.25516,382
11120.2.128.0/18120.2.128.1 to 120.2.191.254120.2.191.25516,382
12120.2.192.0/18120.2.192.1 to 120.2.255.254120.2.255.25516,382
13120.3.0.0/18120.3.0.1 to 120.3.63.254120.3.63.25516,382
14120.3.64.0/18120.3.64.1 to 120.3.127.254120.3.127.25516,382
15120.3.128.0/18120.3.128.1 to 120.3.191.254120.3.191.25516,382
16120.3.192.0/18120.3.192.1 to 120.3.255.254120.3.255.25516,382
17120.4.0.0/18120.4.0.1 to 120.4.63.254120.4.63.25516,382
18120.4.64.0/18120.4.64.1 to 120.4.127.254120.4.127.25516,382
19120.4.128.0/18120.4.128.1 to 120.4.191.254120.4.191.25516,382
20120.4.192.0/18120.4.192.1 to 120.4.255.254120.4.255.25516,382
21120.5.0.0/18120.5.0.1 to 120.5.63.254120.5.63.25516,382
22120.5.64.0/18120.5.64.1 to 120.5.127.254120.5.127.25516,382
23120.5.128.0/18120.5.128.1 to 120.5.191.254120.5.191.25516,382
24120.5.192.0/18120.5.192.1 to 120.5.255.254120.5.255.25516,382
25120.6.0.0/18120.6.0.1 to 120.6.63.254120.6.63.25516,382
26120.6.64.0/18120.6.64.1 to 120.6.127.254120.6.127.25516,382
27120.6.128.0/18120.6.128.1 to 120.6.191.254120.6.191.25516,382
28120.6.192.0/18120.6.192.1 to 120.6.255.254120.6.255.25516,382
29120.7.0.0/18120.7.0.1 to 120.7.63.254120.7.63.25516,382
30120.7.64.0/18120.7.64.1 to 120.7.127.254120.7.127.25516,382
31120.7.128.0/18120.7.128.1 to 120.7.191.254120.7.191.25516,382
32120.7.192.0/18120.7.192.1 to 120.7.255.254120.7.255.25516,382
33120.8.0.0/18120.8.0.1 to 120.8.63.254120.8.63.25516,382
34120.8.64.0/18120.8.64.1 to 120.8.127.254120.8.127.25516,382
35120.8.128.0/18120.8.128.1 to 120.8.191.254120.8.191.25516,382
36120.8.192.0/18120.8.192.1 to 120.8.255.254120.8.255.25516,382
37120.9.0.0/18120.9.0.1 to 120.9.63.254120.9.63.25516,382
38120.9.64.0/18120.9.64.1 to 120.9.127.254120.9.127.25516,382
39120.9.128.0/18120.9.128.1 to 120.9.191.254120.9.191.25516,382
40120.9.192.0/18120.9.192.1 to 120.9.255.254120.9.255.25516,382
41120.10.0.0/18120.10.0.1 to 120.10.63.254120.10.63.25516,382
42120.10.64.0/18120.10.64.1 to 120.10.127.254120.10.127.25516,382
43120.10.128.0/18120.10.128.1 to 120.10.191.254120.10.191.25516,382
44120.10.192.0/18120.10.192.1 to 120.10.255.254120.10.255.25516,382
45120.11.0.0/18120.11.0.1 to 120.11.63.254120.11.63.25516,382
46120.11.64.0/18120.11.64.1 to 120.11.127.254120.11.127.25516,382
47120.11.128.0/18120.11.128.1 to 120.11.191.254120.11.191.25516,382
48120.11.192.0/18120.11.192.1 to 120.11.255.254120.11.255.25516,382
49120.12.0.0/18120.12.0.1 to 120.12.63.254120.12.63.25516,382
50120.12.64.0/18120.12.64.1 to 120.12.127.254120.12.127.25516,382
51120.12.128.0/18120.12.128.1 to 120.12.191.254120.12.191.25516,382
52120.12.192.0/18120.12.192.1 to 120.12.255.254120.12.255.25516,382
53120.13.0.0/18120.13.0.1 to 120.13.63.254120.13.63.25516,382
54120.13.64.0/18120.13.64.1 to 120.13.127.254120.13.127.25516,382
55120.13.128.0/18120.13.128.1 to 120.13.191.254120.13.191.25516,382
56120.13.192.0/18120.13.192.1 to 120.13.255.254120.13.255.25516,382
57120.14.0.0/18120.14.0.1 to 120.14.63.254120.14.63.25516,382
58120.14.64.0/18120.14.64.1 to 120.14.127.254120.14.127.25516,382
59120.14.128.0/18120.14.128.1 to 120.14.191.254120.14.191.25516,382
60120.14.192.0/18120.14.192.1 to 120.14.255.254120.14.255.25516,382
61120.15.0.0/18120.15.0.1 to 120.15.63.254120.15.63.25516,382
62120.15.64.0/18120.15.64.1 to 120.15.127.254120.15.127.25516,382
63120.15.128.0/18120.15.128.1 to 120.15.191.254120.15.191.25516,382
64120.15.192.0/18120.15.192.1 to 120.15.255.254120.15.255.25516,382
65120.16.0.0/18120.16.0.1 to 120.16.63.254120.16.63.25516,382
66120.16.64.0/18120.16.64.1 to 120.16.127.254120.16.127.25516,382
67120.16.128.0/18120.16.128.1 to 120.16.191.254120.16.191.25516,382
68120.16.192.0/18120.16.192.1 to 120.16.255.254120.16.255.25516,382
69120.17.0.0/18120.17.0.1 to 120.17.63.254120.17.63.25516,382
70120.17.64.0/18120.17.64.1 to 120.17.127.254120.17.127.25516,382
71120.17.128.0/18120.17.128.1 to 120.17.191.254120.17.191.25516,382
72120.17.192.0/18120.17.192.1 to 120.17.255.254120.17.255.25516,382
73120.18.0.0/18120.18.0.1 to 120.18.63.254120.18.63.25516,382
74120.18.64.0/18120.18.64.1 to 120.18.127.254120.18.127.25516,382
75120.18.128.0/18120.18.128.1 to 120.18.191.254120.18.191.25516,382
76120.18.192.0/18120.18.192.1 to 120.18.255.254120.18.255.25516,382
77120.19.0.0/18120.19.0.1 to 120.19.63.254120.19.63.25516,382
78120.19.64.0/18120.19.64.1 to 120.19.127.254120.19.127.25516,382
79120.19.128.0/18120.19.128.1 to 120.19.191.254120.19.191.25516,382
80120.19.192.0/18120.19.192.1 to 120.19.255.254120.19.255.25516,382
81120.20.0.0/18120.20.0.1 to 120.20.63.254120.20.63.25516,382
82120.20.64.0/18120.20.64.1 to 120.20.127.254120.20.127.25516,382
83120.20.128.0/18120.20.128.1 to 120.20.191.254120.20.191.25516,382
84120.20.192.0/18120.20.192.1 to 120.20.255.254120.20.255.25516,382
85120.21.0.0/18120.21.0.1 to 120.21.63.254120.21.63.25516,382
86120.21.64.0/18120.21.64.1 to 120.21.127.254120.21.127.25516,382
87120.21.128.0/18120.21.128.1 to 120.21.191.254120.21.191.25516,382
88120.21.192.0/18120.21.192.1 to 120.21.255.254120.21.255.25516,382
89120.22.0.0/18120.22.0.1 to 120.22.63.254120.22.63.25516,382
90120.22.64.0/18120.22.64.1 to 120.22.127.254120.22.127.25516,382
91120.22.128.0/18120.22.128.1 to 120.22.191.254120.22.191.25516,382
92120.22.192.0/18120.22.192.1 to 120.22.255.254120.22.255.25516,382
93120.23.0.0/18120.23.0.1 to 120.23.63.254120.23.63.25516,382
94120.23.64.0/18120.23.64.1 to 120.23.127.254120.23.127.25516,382
95120.23.128.0/18120.23.128.1 to 120.23.191.254120.23.191.25516,382
96120.23.192.0/18120.23.192.1 to 120.23.255.254120.23.255.25516,382
97120.24.0.0/18120.24.0.1 to 120.24.63.254120.24.63.25516,382
98120.24.64.0/18120.24.64.1 to 120.24.127.254120.24.127.25516,382
99120.24.128.0/18120.24.128.1 to 120.24.191.254120.24.191.25516,382
100120.24.192.0/18120.24.192.1 to 120.24.255.254120.24.255.25516,382
101120.25.0.0/18120.25.0.1 to 120.25.63.254120.25.63.25516,382
102120.25.64.0/18120.25.64.1 to 120.25.127.254120.25.127.25516,382
103120.25.128.0/18120.25.128.1 to 120.25.191.254120.25.191.25516,382
104120.25.192.0/18120.25.192.1 to 120.25.255.254120.25.255.25516,382
105120.26.0.0/18120.26.0.1 to 120.26.63.254120.26.63.25516,382
106120.26.64.0/18120.26.64.1 to 120.26.127.254120.26.127.25516,382
107120.26.128.0/18120.26.128.1 to 120.26.191.254120.26.191.25516,382
108120.26.192.0/18120.26.192.1 to 120.26.255.254120.26.255.25516,382
109120.27.0.0/18120.27.0.1 to 120.27.63.254120.27.63.25516,382
110120.27.64.0/18120.27.64.1 to 120.27.127.254120.27.127.25516,382
111120.27.128.0/18120.27.128.1 to 120.27.191.254120.27.191.25516,382
112120.27.192.0/18120.27.192.1 to 120.27.255.254120.27.255.25516,382
113120.28.0.0/18120.28.0.1 to 120.28.63.254120.28.63.25516,382
114120.28.64.0/18120.28.64.1 to 120.28.127.254120.28.127.25516,382
115120.28.128.0/18120.28.128.1 to 120.28.191.254120.28.191.25516,382
116120.28.192.0/18120.28.192.1 to 120.28.255.254120.28.255.25516,382
117120.29.0.0/18120.29.0.1 to 120.29.63.254120.29.63.25516,382
118120.29.64.0/18120.29.64.1 to 120.29.127.254120.29.127.25516,382
119120.29.128.0/18120.29.128.1 to 120.29.191.254120.29.191.25516,382
120120.29.192.0/18120.29.192.1 to 120.29.255.254120.29.255.25516,382
121120.30.0.0/18120.30.0.1 to 120.30.63.254120.30.63.25516,382
122120.30.64.0/18120.30.64.1 to 120.30.127.254120.30.127.25516,382
123120.30.128.0/18120.30.128.1 to 120.30.191.254120.30.191.25516,382
124120.30.192.0/18120.30.192.1 to 120.30.255.254120.30.255.25516,382
125120.31.0.0/18120.31.0.1 to 120.31.63.254120.31.63.25516,382
126120.31.64.0/18120.31.64.1 to 120.31.127.254120.31.127.25516,382
127120.31.128.0/18120.31.128.1 to 120.31.191.254120.31.191.25516,382
128120.31.192.0/18120.31.192.1 to 120.31.255.254120.31.255.25516,382
129120.32.0.0/18120.32.0.1 to 120.32.63.254120.32.63.25516,382
130120.32.64.0/18120.32.64.1 to 120.32.127.254120.32.127.25516,382
131120.32.128.0/18120.32.128.1 to 120.32.191.254120.32.191.25516,382
132120.32.192.0/18120.32.192.1 to 120.32.255.254120.32.255.25516,382
133120.33.0.0/18120.33.0.1 to 120.33.63.254120.33.63.25516,382
134120.33.64.0/18120.33.64.1 to 120.33.127.254120.33.127.25516,382
135120.33.128.0/18120.33.128.1 to 120.33.191.254120.33.191.25516,382
136120.33.192.0/18120.33.192.1 to 120.33.255.254120.33.255.25516,382
137120.34.0.0/18120.34.0.1 to 120.34.63.254120.34.63.25516,382
138120.34.64.0/18120.34.64.1 to 120.34.127.254120.34.127.25516,382
139120.34.128.0/18120.34.128.1 to 120.34.191.254120.34.191.25516,382
140120.34.192.0/18120.34.192.1 to 120.34.255.254120.34.255.25516,382
141120.35.0.0/18120.35.0.1 to 120.35.63.254120.35.63.25516,382
142120.35.64.0/18120.35.64.1 to 120.35.127.254120.35.127.25516,382
143120.35.128.0/18120.35.128.1 to 120.35.191.254120.35.191.25516,382
144120.35.192.0/18120.35.192.1 to 120.35.255.254120.35.255.25516,382
145120.36.0.0/18120.36.0.1 to 120.36.63.254120.36.63.25516,382
146120.36.64.0/18120.36.64.1 to 120.36.127.254120.36.127.25516,382
147120.36.128.0/18120.36.128.1 to 120.36.191.254120.36.191.25516,382
148120.36.192.0/18120.36.192.1 to 120.36.255.254120.36.255.25516,382
149120.37.0.0/18120.37.0.1 to 120.37.63.254120.37.63.25516,382
150120.37.64.0/18120.37.64.1 to 120.37.127.254120.37.127.25516,382
151120.37.128.0/18120.37.128.1 to 120.37.191.254120.37.191.25516,382
152120.37.192.0/18120.37.192.1 to 120.37.255.254120.37.255.25516,382
153120.38.0.0/18120.38.0.1 to 120.38.63.254120.38.63.25516,382
154120.38.64.0/18120.38.64.1 to 120.38.127.254120.38.127.25516,382
155120.38.128.0/18120.38.128.1 to 120.38.191.254120.38.191.25516,382
156120.38.192.0/18120.38.192.1 to 120.38.255.254120.38.255.25516,382
157120.39.0.0/18120.39.0.1 to 120.39.63.254120.39.63.25516,382
158120.39.64.0/18120.39.64.1 to 120.39.127.254120.39.127.25516,382
159120.39.128.0/18120.39.128.1 to 120.39.191.254120.39.191.25516,382
160120.39.192.0/18120.39.192.1 to 120.39.255.254120.39.255.25516,382
161120.40.0.0/18120.40.0.1 to 120.40.63.254120.40.63.25516,382
162120.40.64.0/18120.40.64.1 to 120.40.127.254120.40.127.25516,382
163120.40.128.0/18120.40.128.1 to 120.40.191.254120.40.191.25516,382
164120.40.192.0/18120.40.192.1 to 120.40.255.254120.40.255.25516,382
165120.41.0.0/18120.41.0.1 to 120.41.63.254120.41.63.25516,382
166120.41.64.0/18120.41.64.1 to 120.41.127.254120.41.127.25516,382
167120.41.128.0/18120.41.128.1 to 120.41.191.254120.41.191.25516,382
168120.41.192.0/18120.41.192.1 to 120.41.255.254120.41.255.25516,382
169120.42.0.0/18120.42.0.1 to 120.42.63.254120.42.63.25516,382
170120.42.64.0/18120.42.64.1 to 120.42.127.254120.42.127.25516,382
171120.42.128.0/18120.42.128.1 to 120.42.191.254120.42.191.25516,382
172120.42.192.0/18120.42.192.1 to 120.42.255.254120.42.255.25516,382
173120.43.0.0/18120.43.0.1 to 120.43.63.254120.43.63.25516,382
174120.43.64.0/18120.43.64.1 to 120.43.127.254120.43.127.25516,382
175120.43.128.0/18120.43.128.1 to 120.43.191.254120.43.191.25516,382
176120.43.192.0/18120.43.192.1 to 120.43.255.254120.43.255.25516,382
177120.44.0.0/18120.44.0.1 to 120.44.63.254120.44.63.25516,382
178120.44.64.0/18120.44.64.1 to 120.44.127.254120.44.127.25516,382
179120.44.128.0/18120.44.128.1 to 120.44.191.254120.44.191.25516,382
180120.44.192.0/18120.44.192.1 to 120.44.255.254120.44.255.25516,382
181120.45.0.0/18120.45.0.1 to 120.45.63.254120.45.63.25516,382
182120.45.64.0/18120.45.64.1 to 120.45.127.254120.45.127.25516,382
183120.45.128.0/18120.45.128.1 to 120.45.191.254120.45.191.25516,382
184120.45.192.0/18120.45.192.1 to 120.45.255.254120.45.255.25516,382
185120.46.0.0/18120.46.0.1 to 120.46.63.254120.46.63.25516,382
186120.46.64.0/18120.46.64.1 to 120.46.127.254120.46.127.25516,382
187120.46.128.0/18120.46.128.1 to 120.46.191.254120.46.191.25516,382
188120.46.192.0/18120.46.192.1 to 120.46.255.254120.46.255.25516,382
189120.47.0.0/18120.47.0.1 to 120.47.63.254120.47.63.25516,382
190120.47.64.0/18120.47.64.1 to 120.47.127.254120.47.127.25516,382
191120.47.128.0/18120.47.128.1 to 120.47.191.254120.47.191.25516,382
192120.47.192.0/18120.47.192.1 to 120.47.255.254120.47.255.25516,382
193120.48.0.0/18120.48.0.1 to 120.48.63.254120.48.63.25516,382
194120.48.64.0/18120.48.64.1 to 120.48.127.254120.48.127.25516,382
195120.48.128.0/18120.48.128.1 to 120.48.191.254120.48.191.25516,382
196120.48.192.0/18120.48.192.1 to 120.48.255.254120.48.255.25516,382
197120.49.0.0/18120.49.0.1 to 120.49.63.254120.49.63.25516,382
198120.49.64.0/18120.49.64.1 to 120.49.127.254120.49.127.25516,382
199120.49.128.0/18120.49.128.1 to 120.49.191.254120.49.191.25516,382
200120.49.192.0/18120.49.192.1 to 120.49.255.254120.49.255.25516,382
201120.50.0.0/18120.50.0.1 to 120.50.63.254120.50.63.25516,382
202120.50.64.0/18120.50.64.1 to 120.50.127.254120.50.127.25516,382
203120.50.128.0/18120.50.128.1 to 120.50.191.254120.50.191.25516,382
204120.50.192.0/18120.50.192.1 to 120.50.255.254120.50.255.25516,382
205120.51.0.0/18120.51.0.1 to 120.51.63.254120.51.63.25516,382
206120.51.64.0/18120.51.64.1 to 120.51.127.254120.51.127.25516,382
207120.51.128.0/18120.51.128.1 to 120.51.191.254120.51.191.25516,382
208120.51.192.0/18120.51.192.1 to 120.51.255.254120.51.255.25516,382
209120.52.0.0/18120.52.0.1 to 120.52.63.254120.52.63.25516,382
210120.52.64.0/18120.52.64.1 to 120.52.127.254120.52.127.25516,382
211120.52.128.0/18120.52.128.1 to 120.52.191.254120.52.191.25516,382
212120.52.192.0/18120.52.192.1 to 120.52.255.254120.52.255.25516,382
213120.53.0.0/18120.53.0.1 to 120.53.63.254120.53.63.25516,382
214120.53.64.0/18120.53.64.1 to 120.53.127.254120.53.127.25516,382
215120.53.128.0/18120.53.128.1 to 120.53.191.254120.53.191.25516,382
216120.53.192.0/18120.53.192.1 to 120.53.255.254120.53.255.25516,382
217120.54.0.0/18120.54.0.1 to 120.54.63.254120.54.63.25516,382
218120.54.64.0/18120.54.64.1 to 120.54.127.254120.54.127.25516,382
219120.54.128.0/18120.54.128.1 to 120.54.191.254120.54.191.25516,382
220120.54.192.0/18120.54.192.1 to 120.54.255.254120.54.255.25516,382
221120.55.0.0/18120.55.0.1 to 120.55.63.254120.55.63.25516,382
222120.55.64.0/18120.55.64.1 to 120.55.127.254120.55.127.25516,382
223120.55.128.0/18120.55.128.1 to 120.55.191.254120.55.191.25516,382
224120.55.192.0/18120.55.192.1 to 120.55.255.254120.55.255.25516,382
225120.56.0.0/18120.56.0.1 to 120.56.63.254120.56.63.25516,382
226120.56.64.0/18120.56.64.1 to 120.56.127.254120.56.127.25516,382
227120.56.128.0/18120.56.128.1 to 120.56.191.254120.56.191.25516,382
228120.56.192.0/18120.56.192.1 to 120.56.255.254120.56.255.25516,382
229120.57.0.0/18120.57.0.1 to 120.57.63.254120.57.63.25516,382
230120.57.64.0/18120.57.64.1 to 120.57.127.254120.57.127.25516,382
231120.57.128.0/18120.57.128.1 to 120.57.191.254120.57.191.25516,382
232120.57.192.0/18120.57.192.1 to 120.57.255.254120.57.255.25516,382
233120.58.0.0/18120.58.0.1 to 120.58.63.254120.58.63.25516,382
234120.58.64.0/18120.58.64.1 to 120.58.127.254120.58.127.25516,382
235120.58.128.0/18120.58.128.1 to 120.58.191.254120.58.191.25516,382
236120.58.192.0/18120.58.192.1 to 120.58.255.254120.58.255.25516,382
237120.59.0.0/18120.59.0.1 to 120.59.63.254120.59.63.25516,382
238120.59.64.0/18120.59.64.1 to 120.59.127.254120.59.127.25516,382
239120.59.128.0/18120.59.128.1 to 120.59.191.254120.59.191.25516,382
240120.59.192.0/18120.59.192.1 to 120.59.255.254120.59.255.25516,382
241120.60.0.0/18120.60.0.1 to 120.60.63.254120.60.63.25516,382
242120.60.64.0/18120.60.64.1 to 120.60.127.254120.60.127.25516,382
243120.60.128.0/18120.60.128.1 to 120.60.191.254120.60.191.25516,382
244120.60.192.0/18120.60.192.1 to 120.60.255.254120.60.255.25516,382
245120.61.0.0/18120.61.0.1 to 120.61.63.254120.61.63.25516,382
246120.61.64.0/18120.61.64.1 to 120.61.127.254120.61.127.25516,382
247120.61.128.0/18120.61.128.1 to 120.61.191.254120.61.191.25516,382
248120.61.192.0/18120.61.192.1 to 120.61.255.254120.61.255.25516,382
249120.62.0.0/18120.62.0.1 to 120.62.63.254120.62.63.25516,382
250120.62.64.0/18120.62.64.1 to 120.62.127.254120.62.127.25516,382
251120.62.128.0/18120.62.128.1 to 120.62.191.254120.62.191.25516,382
252120.62.192.0/18120.62.192.1 to 120.62.255.254120.62.255.25516,382
253120.63.0.0/18120.63.0.1 to 120.63.63.254120.63.63.25516,382
254120.63.64.0/18120.63.64.1 to 120.63.127.254120.63.127.25516,382
255120.63.128.0/18120.63.128.1 to 120.63.191.254120.63.191.25516,382
256120.63.192.0/18120.63.192.1 to 120.63.255.254120.63.255.25516,382

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.