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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.

Network120.0.0.0/6
Usable hosts67,108,862
Subnet mask252.0.0.0
Addresses67,108,864
Network address
120.0.0.0
Broadcast address
123.255.255.255
First usable
120.0.0.1
Last usable
123.255.255.254
Usable hosts
67,108,862 (67,108,864 less the network and broadcast addresses)
Subnet mask
252.0.0.0
Wildcard mask
3.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/6
Type
Public public
Old class
A (default /8)
As numbers
Hex 78000000 · Integer 2013265920 to 2080374783
Reverse DNS zones
120.in-addr.arpa
121.in-addr.arpa
122.in-addr.arpa
123.in-addr.arpa
/6 is not on a 8-bit boundary, so it takes 4 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01111000.00000000.00000000.00000000120.0.0.0
Subnet mask11111100.00000000.00000000.00000000252.0.0.0
Network01111000.00000000.00000000.00000000120.0.0.0
Broadcast01111011.11111111.11111111.11111111123.255.255.255
Split into smaller subnets/17
/7 (2)/8 (4)/9 (8)/10 (16)/11 (32)/12 (64)/13 (128)/14 (256)/15 (512)/16 (1,024)/17 (2,048)/18 (4,096)

120.0.0.0/6 makes 2,048 subnets of /17; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1120.0.0.0/17120.0.0.1 to 120.0.127.254120.0.127.25532,766
2120.0.128.0/17120.0.128.1 to 120.0.255.254120.0.255.25532,766
3120.1.0.0/17120.1.0.1 to 120.1.127.254120.1.127.25532,766
4120.1.128.0/17120.1.128.1 to 120.1.255.254120.1.255.25532,766
5120.2.0.0/17120.2.0.1 to 120.2.127.254120.2.127.25532,766
6120.2.128.0/17120.2.128.1 to 120.2.255.254120.2.255.25532,766
7120.3.0.0/17120.3.0.1 to 120.3.127.254120.3.127.25532,766
8120.3.128.0/17120.3.128.1 to 120.3.255.254120.3.255.25532,766
9120.4.0.0/17120.4.0.1 to 120.4.127.254120.4.127.25532,766
10120.4.128.0/17120.4.128.1 to 120.4.255.254120.4.255.25532,766
11120.5.0.0/17120.5.0.1 to 120.5.127.254120.5.127.25532,766
12120.5.128.0/17120.5.128.1 to 120.5.255.254120.5.255.25532,766
13120.6.0.0/17120.6.0.1 to 120.6.127.254120.6.127.25532,766
14120.6.128.0/17120.6.128.1 to 120.6.255.254120.6.255.25532,766
15120.7.0.0/17120.7.0.1 to 120.7.127.254120.7.127.25532,766
16120.7.128.0/17120.7.128.1 to 120.7.255.254120.7.255.25532,766
17120.8.0.0/17120.8.0.1 to 120.8.127.254120.8.127.25532,766
18120.8.128.0/17120.8.128.1 to 120.8.255.254120.8.255.25532,766
19120.9.0.0/17120.9.0.1 to 120.9.127.254120.9.127.25532,766
20120.9.128.0/17120.9.128.1 to 120.9.255.254120.9.255.25532,766
21120.10.0.0/17120.10.0.1 to 120.10.127.254120.10.127.25532,766
22120.10.128.0/17120.10.128.1 to 120.10.255.254120.10.255.25532,766
23120.11.0.0/17120.11.0.1 to 120.11.127.254120.11.127.25532,766
24120.11.128.0/17120.11.128.1 to 120.11.255.254120.11.255.25532,766
25120.12.0.0/17120.12.0.1 to 120.12.127.254120.12.127.25532,766
26120.12.128.0/17120.12.128.1 to 120.12.255.254120.12.255.25532,766
27120.13.0.0/17120.13.0.1 to 120.13.127.254120.13.127.25532,766
28120.13.128.0/17120.13.128.1 to 120.13.255.254120.13.255.25532,766
29120.14.0.0/17120.14.0.1 to 120.14.127.254120.14.127.25532,766
30120.14.128.0/17120.14.128.1 to 120.14.255.254120.14.255.25532,766
31120.15.0.0/17120.15.0.1 to 120.15.127.254120.15.127.25532,766
32120.15.128.0/17120.15.128.1 to 120.15.255.254120.15.255.25532,766
33120.16.0.0/17120.16.0.1 to 120.16.127.254120.16.127.25532,766
34120.16.128.0/17120.16.128.1 to 120.16.255.254120.16.255.25532,766
35120.17.0.0/17120.17.0.1 to 120.17.127.254120.17.127.25532,766
36120.17.128.0/17120.17.128.1 to 120.17.255.254120.17.255.25532,766
37120.18.0.0/17120.18.0.1 to 120.18.127.254120.18.127.25532,766
38120.18.128.0/17120.18.128.1 to 120.18.255.254120.18.255.25532,766
39120.19.0.0/17120.19.0.1 to 120.19.127.254120.19.127.25532,766
40120.19.128.0/17120.19.128.1 to 120.19.255.254120.19.255.25532,766
41120.20.0.0/17120.20.0.1 to 120.20.127.254120.20.127.25532,766
42120.20.128.0/17120.20.128.1 to 120.20.255.254120.20.255.25532,766
43120.21.0.0/17120.21.0.1 to 120.21.127.254120.21.127.25532,766
44120.21.128.0/17120.21.128.1 to 120.21.255.254120.21.255.25532,766
45120.22.0.0/17120.22.0.1 to 120.22.127.254120.22.127.25532,766
46120.22.128.0/17120.22.128.1 to 120.22.255.254120.22.255.25532,766
47120.23.0.0/17120.23.0.1 to 120.23.127.254120.23.127.25532,766
48120.23.128.0/17120.23.128.1 to 120.23.255.254120.23.255.25532,766
49120.24.0.0/17120.24.0.1 to 120.24.127.254120.24.127.25532,766
50120.24.128.0/17120.24.128.1 to 120.24.255.254120.24.255.25532,766
51120.25.0.0/17120.25.0.1 to 120.25.127.254120.25.127.25532,766
52120.25.128.0/17120.25.128.1 to 120.25.255.254120.25.255.25532,766
53120.26.0.0/17120.26.0.1 to 120.26.127.254120.26.127.25532,766
54120.26.128.0/17120.26.128.1 to 120.26.255.254120.26.255.25532,766
55120.27.0.0/17120.27.0.1 to 120.27.127.254120.27.127.25532,766
56120.27.128.0/17120.27.128.1 to 120.27.255.254120.27.255.25532,766
57120.28.0.0/17120.28.0.1 to 120.28.127.254120.28.127.25532,766
58120.28.128.0/17120.28.128.1 to 120.28.255.254120.28.255.25532,766
59120.29.0.0/17120.29.0.1 to 120.29.127.254120.29.127.25532,766
60120.29.128.0/17120.29.128.1 to 120.29.255.254120.29.255.25532,766
61120.30.0.0/17120.30.0.1 to 120.30.127.254120.30.127.25532,766
62120.30.128.0/17120.30.128.1 to 120.30.255.254120.30.255.25532,766
63120.31.0.0/17120.31.0.1 to 120.31.127.254120.31.127.25532,766
64120.31.128.0/17120.31.128.1 to 120.31.255.254120.31.255.25532,766
65120.32.0.0/17120.32.0.1 to 120.32.127.254120.32.127.25532,766
66120.32.128.0/17120.32.128.1 to 120.32.255.254120.32.255.25532,766
67120.33.0.0/17120.33.0.1 to 120.33.127.254120.33.127.25532,766
68120.33.128.0/17120.33.128.1 to 120.33.255.254120.33.255.25532,766
69120.34.0.0/17120.34.0.1 to 120.34.127.254120.34.127.25532,766
70120.34.128.0/17120.34.128.1 to 120.34.255.254120.34.255.25532,766
71120.35.0.0/17120.35.0.1 to 120.35.127.254120.35.127.25532,766
72120.35.128.0/17120.35.128.1 to 120.35.255.254120.35.255.25532,766
73120.36.0.0/17120.36.0.1 to 120.36.127.254120.36.127.25532,766
74120.36.128.0/17120.36.128.1 to 120.36.255.254120.36.255.25532,766
75120.37.0.0/17120.37.0.1 to 120.37.127.254120.37.127.25532,766
76120.37.128.0/17120.37.128.1 to 120.37.255.254120.37.255.25532,766
77120.38.0.0/17120.38.0.1 to 120.38.127.254120.38.127.25532,766
78120.38.128.0/17120.38.128.1 to 120.38.255.254120.38.255.25532,766
79120.39.0.0/17120.39.0.1 to 120.39.127.254120.39.127.25532,766
80120.39.128.0/17120.39.128.1 to 120.39.255.254120.39.255.25532,766
81120.40.0.0/17120.40.0.1 to 120.40.127.254120.40.127.25532,766
82120.40.128.0/17120.40.128.1 to 120.40.255.254120.40.255.25532,766
83120.41.0.0/17120.41.0.1 to 120.41.127.254120.41.127.25532,766
84120.41.128.0/17120.41.128.1 to 120.41.255.254120.41.255.25532,766
85120.42.0.0/17120.42.0.1 to 120.42.127.254120.42.127.25532,766
86120.42.128.0/17120.42.128.1 to 120.42.255.254120.42.255.25532,766
87120.43.0.0/17120.43.0.1 to 120.43.127.254120.43.127.25532,766
88120.43.128.0/17120.43.128.1 to 120.43.255.254120.43.255.25532,766
89120.44.0.0/17120.44.0.1 to 120.44.127.254120.44.127.25532,766
90120.44.128.0/17120.44.128.1 to 120.44.255.254120.44.255.25532,766
91120.45.0.0/17120.45.0.1 to 120.45.127.254120.45.127.25532,766
92120.45.128.0/17120.45.128.1 to 120.45.255.254120.45.255.25532,766
93120.46.0.0/17120.46.0.1 to 120.46.127.254120.46.127.25532,766
94120.46.128.0/17120.46.128.1 to 120.46.255.254120.46.255.25532,766
95120.47.0.0/17120.47.0.1 to 120.47.127.254120.47.127.25532,766
96120.47.128.0/17120.47.128.1 to 120.47.255.254120.47.255.25532,766
97120.48.0.0/17120.48.0.1 to 120.48.127.254120.48.127.25532,766
98120.48.128.0/17120.48.128.1 to 120.48.255.254120.48.255.25532,766
99120.49.0.0/17120.49.0.1 to 120.49.127.254120.49.127.25532,766
100120.49.128.0/17120.49.128.1 to 120.49.255.254120.49.255.25532,766
101120.50.0.0/17120.50.0.1 to 120.50.127.254120.50.127.25532,766
102120.50.128.0/17120.50.128.1 to 120.50.255.254120.50.255.25532,766
103120.51.0.0/17120.51.0.1 to 120.51.127.254120.51.127.25532,766
104120.51.128.0/17120.51.128.1 to 120.51.255.254120.51.255.25532,766
105120.52.0.0/17120.52.0.1 to 120.52.127.254120.52.127.25532,766
106120.52.128.0/17120.52.128.1 to 120.52.255.254120.52.255.25532,766
107120.53.0.0/17120.53.0.1 to 120.53.127.254120.53.127.25532,766
108120.53.128.0/17120.53.128.1 to 120.53.255.254120.53.255.25532,766
109120.54.0.0/17120.54.0.1 to 120.54.127.254120.54.127.25532,766
110120.54.128.0/17120.54.128.1 to 120.54.255.254120.54.255.25532,766
111120.55.0.0/17120.55.0.1 to 120.55.127.254120.55.127.25532,766
112120.55.128.0/17120.55.128.1 to 120.55.255.254120.55.255.25532,766
113120.56.0.0/17120.56.0.1 to 120.56.127.254120.56.127.25532,766
114120.56.128.0/17120.56.128.1 to 120.56.255.254120.56.255.25532,766
115120.57.0.0/17120.57.0.1 to 120.57.127.254120.57.127.25532,766
116120.57.128.0/17120.57.128.1 to 120.57.255.254120.57.255.25532,766
117120.58.0.0/17120.58.0.1 to 120.58.127.254120.58.127.25532,766
118120.58.128.0/17120.58.128.1 to 120.58.255.254120.58.255.25532,766
119120.59.0.0/17120.59.0.1 to 120.59.127.254120.59.127.25532,766
120120.59.128.0/17120.59.128.1 to 120.59.255.254120.59.255.25532,766
121120.60.0.0/17120.60.0.1 to 120.60.127.254120.60.127.25532,766
122120.60.128.0/17120.60.128.1 to 120.60.255.254120.60.255.25532,766
123120.61.0.0/17120.61.0.1 to 120.61.127.254120.61.127.25532,766
124120.61.128.0/17120.61.128.1 to 120.61.255.254120.61.255.25532,766
125120.62.0.0/17120.62.0.1 to 120.62.127.254120.62.127.25532,766
126120.62.128.0/17120.62.128.1 to 120.62.255.254120.62.255.25532,766
127120.63.0.0/17120.63.0.1 to 120.63.127.254120.63.127.25532,766
128120.63.128.0/17120.63.128.1 to 120.63.255.254120.63.255.25532,766
129120.64.0.0/17120.64.0.1 to 120.64.127.254120.64.127.25532,766
130120.64.128.0/17120.64.128.1 to 120.64.255.254120.64.255.25532,766
131120.65.0.0/17120.65.0.1 to 120.65.127.254120.65.127.25532,766
132120.65.128.0/17120.65.128.1 to 120.65.255.254120.65.255.25532,766
133120.66.0.0/17120.66.0.1 to 120.66.127.254120.66.127.25532,766
134120.66.128.0/17120.66.128.1 to 120.66.255.254120.66.255.25532,766
135120.67.0.0/17120.67.0.1 to 120.67.127.254120.67.127.25532,766
136120.67.128.0/17120.67.128.1 to 120.67.255.254120.67.255.25532,766
137120.68.0.0/17120.68.0.1 to 120.68.127.254120.68.127.25532,766
138120.68.128.0/17120.68.128.1 to 120.68.255.254120.68.255.25532,766
139120.69.0.0/17120.69.0.1 to 120.69.127.254120.69.127.25532,766
140120.69.128.0/17120.69.128.1 to 120.69.255.254120.69.255.25532,766
141120.70.0.0/17120.70.0.1 to 120.70.127.254120.70.127.25532,766
142120.70.128.0/17120.70.128.1 to 120.70.255.254120.70.255.25532,766
143120.71.0.0/17120.71.0.1 to 120.71.127.254120.71.127.25532,766
144120.71.128.0/17120.71.128.1 to 120.71.255.254120.71.255.25532,766
145120.72.0.0/17120.72.0.1 to 120.72.127.254120.72.127.25532,766
146120.72.128.0/17120.72.128.1 to 120.72.255.254120.72.255.25532,766
147120.73.0.0/17120.73.0.1 to 120.73.127.254120.73.127.25532,766
148120.73.128.0/17120.73.128.1 to 120.73.255.254120.73.255.25532,766
149120.74.0.0/17120.74.0.1 to 120.74.127.254120.74.127.25532,766
150120.74.128.0/17120.74.128.1 to 120.74.255.254120.74.255.25532,766
151120.75.0.0/17120.75.0.1 to 120.75.127.254120.75.127.25532,766
152120.75.128.0/17120.75.128.1 to 120.75.255.254120.75.255.25532,766
153120.76.0.0/17120.76.0.1 to 120.76.127.254120.76.127.25532,766
154120.76.128.0/17120.76.128.1 to 120.76.255.254120.76.255.25532,766
155120.77.0.0/17120.77.0.1 to 120.77.127.254120.77.127.25532,766
156120.77.128.0/17120.77.128.1 to 120.77.255.254120.77.255.25532,766
157120.78.0.0/17120.78.0.1 to 120.78.127.254120.78.127.25532,766
158120.78.128.0/17120.78.128.1 to 120.78.255.254120.78.255.25532,766
159120.79.0.0/17120.79.0.1 to 120.79.127.254120.79.127.25532,766
160120.79.128.0/17120.79.128.1 to 120.79.255.254120.79.255.25532,766
161120.80.0.0/17120.80.0.1 to 120.80.127.254120.80.127.25532,766
162120.80.128.0/17120.80.128.1 to 120.80.255.254120.80.255.25532,766
163120.81.0.0/17120.81.0.1 to 120.81.127.254120.81.127.25532,766
164120.81.128.0/17120.81.128.1 to 120.81.255.254120.81.255.25532,766
165120.82.0.0/17120.82.0.1 to 120.82.127.254120.82.127.25532,766
166120.82.128.0/17120.82.128.1 to 120.82.255.254120.82.255.25532,766
167120.83.0.0/17120.83.0.1 to 120.83.127.254120.83.127.25532,766
168120.83.128.0/17120.83.128.1 to 120.83.255.254120.83.255.25532,766
169120.84.0.0/17120.84.0.1 to 120.84.127.254120.84.127.25532,766
170120.84.128.0/17120.84.128.1 to 120.84.255.254120.84.255.25532,766
171120.85.0.0/17120.85.0.1 to 120.85.127.254120.85.127.25532,766
172120.85.128.0/17120.85.128.1 to 120.85.255.254120.85.255.25532,766
173120.86.0.0/17120.86.0.1 to 120.86.127.254120.86.127.25532,766
174120.86.128.0/17120.86.128.1 to 120.86.255.254120.86.255.25532,766
175120.87.0.0/17120.87.0.1 to 120.87.127.254120.87.127.25532,766
176120.87.128.0/17120.87.128.1 to 120.87.255.254120.87.255.25532,766
177120.88.0.0/17120.88.0.1 to 120.88.127.254120.88.127.25532,766
178120.88.128.0/17120.88.128.1 to 120.88.255.254120.88.255.25532,766
179120.89.0.0/17120.89.0.1 to 120.89.127.254120.89.127.25532,766
180120.89.128.0/17120.89.128.1 to 120.89.255.254120.89.255.25532,766
181120.90.0.0/17120.90.0.1 to 120.90.127.254120.90.127.25532,766
182120.90.128.0/17120.90.128.1 to 120.90.255.254120.90.255.25532,766
183120.91.0.0/17120.91.0.1 to 120.91.127.254120.91.127.25532,766
184120.91.128.0/17120.91.128.1 to 120.91.255.254120.91.255.25532,766
185120.92.0.0/17120.92.0.1 to 120.92.127.254120.92.127.25532,766
186120.92.128.0/17120.92.128.1 to 120.92.255.254120.92.255.25532,766
187120.93.0.0/17120.93.0.1 to 120.93.127.254120.93.127.25532,766
188120.93.128.0/17120.93.128.1 to 120.93.255.254120.93.255.25532,766
189120.94.0.0/17120.94.0.1 to 120.94.127.254120.94.127.25532,766
190120.94.128.0/17120.94.128.1 to 120.94.255.254120.94.255.25532,766
191120.95.0.0/17120.95.0.1 to 120.95.127.254120.95.127.25532,766
192120.95.128.0/17120.95.128.1 to 120.95.255.254120.95.255.25532,766
193120.96.0.0/17120.96.0.1 to 120.96.127.254120.96.127.25532,766
194120.96.128.0/17120.96.128.1 to 120.96.255.254120.96.255.25532,766
195120.97.0.0/17120.97.0.1 to 120.97.127.254120.97.127.25532,766
196120.97.128.0/17120.97.128.1 to 120.97.255.254120.97.255.25532,766
197120.98.0.0/17120.98.0.1 to 120.98.127.254120.98.127.25532,766
198120.98.128.0/17120.98.128.1 to 120.98.255.254120.98.255.25532,766
199120.99.0.0/17120.99.0.1 to 120.99.127.254120.99.127.25532,766
200120.99.128.0/17120.99.128.1 to 120.99.255.254120.99.255.25532,766
201120.100.0.0/17120.100.0.1 to 120.100.127.254120.100.127.25532,766
202120.100.128.0/17120.100.128.1 to 120.100.255.254120.100.255.25532,766
203120.101.0.0/17120.101.0.1 to 120.101.127.254120.101.127.25532,766
204120.101.128.0/17120.101.128.1 to 120.101.255.254120.101.255.25532,766
205120.102.0.0/17120.102.0.1 to 120.102.127.254120.102.127.25532,766
206120.102.128.0/17120.102.128.1 to 120.102.255.254120.102.255.25532,766
207120.103.0.0/17120.103.0.1 to 120.103.127.254120.103.127.25532,766
208120.103.128.0/17120.103.128.1 to 120.103.255.254120.103.255.25532,766
209120.104.0.0/17120.104.0.1 to 120.104.127.254120.104.127.25532,766
210120.104.128.0/17120.104.128.1 to 120.104.255.254120.104.255.25532,766
211120.105.0.0/17120.105.0.1 to 120.105.127.254120.105.127.25532,766
212120.105.128.0/17120.105.128.1 to 120.105.255.254120.105.255.25532,766
213120.106.0.0/17120.106.0.1 to 120.106.127.254120.106.127.25532,766
214120.106.128.0/17120.106.128.1 to 120.106.255.254120.106.255.25532,766
215120.107.0.0/17120.107.0.1 to 120.107.127.254120.107.127.25532,766
216120.107.128.0/17120.107.128.1 to 120.107.255.254120.107.255.25532,766
217120.108.0.0/17120.108.0.1 to 120.108.127.254120.108.127.25532,766
218120.108.128.0/17120.108.128.1 to 120.108.255.254120.108.255.25532,766
219120.109.0.0/17120.109.0.1 to 120.109.127.254120.109.127.25532,766
220120.109.128.0/17120.109.128.1 to 120.109.255.254120.109.255.25532,766
221120.110.0.0/17120.110.0.1 to 120.110.127.254120.110.127.25532,766
222120.110.128.0/17120.110.128.1 to 120.110.255.254120.110.255.25532,766
223120.111.0.0/17120.111.0.1 to 120.111.127.254120.111.127.25532,766
224120.111.128.0/17120.111.128.1 to 120.111.255.254120.111.255.25532,766
225120.112.0.0/17120.112.0.1 to 120.112.127.254120.112.127.25532,766
226120.112.128.0/17120.112.128.1 to 120.112.255.254120.112.255.25532,766
227120.113.0.0/17120.113.0.1 to 120.113.127.254120.113.127.25532,766
228120.113.128.0/17120.113.128.1 to 120.113.255.254120.113.255.25532,766
229120.114.0.0/17120.114.0.1 to 120.114.127.254120.114.127.25532,766
230120.114.128.0/17120.114.128.1 to 120.114.255.254120.114.255.25532,766
231120.115.0.0/17120.115.0.1 to 120.115.127.254120.115.127.25532,766
232120.115.128.0/17120.115.128.1 to 120.115.255.254120.115.255.25532,766
233120.116.0.0/17120.116.0.1 to 120.116.127.254120.116.127.25532,766
234120.116.128.0/17120.116.128.1 to 120.116.255.254120.116.255.25532,766
235120.117.0.0/17120.117.0.1 to 120.117.127.254120.117.127.25532,766
236120.117.128.0/17120.117.128.1 to 120.117.255.254120.117.255.25532,766
237120.118.0.0/17120.118.0.1 to 120.118.127.254120.118.127.25532,766
238120.118.128.0/17120.118.128.1 to 120.118.255.254120.118.255.25532,766
239120.119.0.0/17120.119.0.1 to 120.119.127.254120.119.127.25532,766
240120.119.128.0/17120.119.128.1 to 120.119.255.254120.119.255.25532,766
241120.120.0.0/17120.120.0.1 to 120.120.127.254120.120.127.25532,766
242120.120.128.0/17120.120.128.1 to 120.120.255.254120.120.255.25532,766
243120.121.0.0/17120.121.0.1 to 120.121.127.254120.121.127.25532,766
244120.121.128.0/17120.121.128.1 to 120.121.255.254120.121.255.25532,766
245120.122.0.0/17120.122.0.1 to 120.122.127.254120.122.127.25532,766
246120.122.128.0/17120.122.128.1 to 120.122.255.254120.122.255.25532,766
247120.123.0.0/17120.123.0.1 to 120.123.127.254120.123.127.25532,766
248120.123.128.0/17120.123.128.1 to 120.123.255.254120.123.255.25532,766
249120.124.0.0/17120.124.0.1 to 120.124.127.254120.124.127.25532,766
250120.124.128.0/17120.124.128.1 to 120.124.255.254120.124.255.25532,766
251120.125.0.0/17120.125.0.1 to 120.125.127.254120.125.127.25532,766
252120.125.128.0/17120.125.128.1 to 120.125.255.254120.125.255.25532,766
253120.126.0.0/17120.126.0.1 to 120.126.127.254120.126.127.25532,766
254120.126.128.0/17120.126.128.1 to 120.126.255.254120.126.255.25532,766
255120.127.0.0/17120.127.0.1 to 120.127.127.254120.127.127.25532,766
256120.127.128.0/17120.127.128.1 to 120.127.255.254120.127.255.25532,766

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.