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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.

Network210.0.0.0/7
Usable hosts33,554,430
Subnet mask254.0.0.0
Addresses33,554,432
Network address
210.0.0.0
Broadcast address
211.255.255.255
First usable
210.0.0.1
Last usable
211.255.255.254
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
C (default /24)
As numbers
Hex D2000000 · Integer 3523215360 to 3556769791
Reverse DNS zones
210.in-addr.arpa
211.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
Address11010010.00000000.00000000.00000000210.0.0.0
Subnet mask11111110.00000000.00000000.00000000254.0.0.0
Network11010010.00000000.00000000.00000000210.0.0.0
Broadcast11010011.11111111.11111111.11111111211.255.255.255
Split into smaller subnets/17
/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)

210.0.0.0/7 makes 1,024 subnets of /17; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1210.0.0.0/17210.0.0.1 to 210.0.127.254210.0.127.25532,766
2210.0.128.0/17210.0.128.1 to 210.0.255.254210.0.255.25532,766
3210.1.0.0/17210.1.0.1 to 210.1.127.254210.1.127.25532,766
4210.1.128.0/17210.1.128.1 to 210.1.255.254210.1.255.25532,766
5210.2.0.0/17210.2.0.1 to 210.2.127.254210.2.127.25532,766
6210.2.128.0/17210.2.128.1 to 210.2.255.254210.2.255.25532,766
7210.3.0.0/17210.3.0.1 to 210.3.127.254210.3.127.25532,766
8210.3.128.0/17210.3.128.1 to 210.3.255.254210.3.255.25532,766
9210.4.0.0/17210.4.0.1 to 210.4.127.254210.4.127.25532,766
10210.4.128.0/17210.4.128.1 to 210.4.255.254210.4.255.25532,766
11210.5.0.0/17210.5.0.1 to 210.5.127.254210.5.127.25532,766
12210.5.128.0/17210.5.128.1 to 210.5.255.254210.5.255.25532,766
13210.6.0.0/17210.6.0.1 to 210.6.127.254210.6.127.25532,766
14210.6.128.0/17210.6.128.1 to 210.6.255.254210.6.255.25532,766
15210.7.0.0/17210.7.0.1 to 210.7.127.254210.7.127.25532,766
16210.7.128.0/17210.7.128.1 to 210.7.255.254210.7.255.25532,766
17210.8.0.0/17210.8.0.1 to 210.8.127.254210.8.127.25532,766
18210.8.128.0/17210.8.128.1 to 210.8.255.254210.8.255.25532,766
19210.9.0.0/17210.9.0.1 to 210.9.127.254210.9.127.25532,766
20210.9.128.0/17210.9.128.1 to 210.9.255.254210.9.255.25532,766
21210.10.0.0/17210.10.0.1 to 210.10.127.254210.10.127.25532,766
22210.10.128.0/17210.10.128.1 to 210.10.255.254210.10.255.25532,766
23210.11.0.0/17210.11.0.1 to 210.11.127.254210.11.127.25532,766
24210.11.128.0/17210.11.128.1 to 210.11.255.254210.11.255.25532,766
25210.12.0.0/17210.12.0.1 to 210.12.127.254210.12.127.25532,766
26210.12.128.0/17210.12.128.1 to 210.12.255.254210.12.255.25532,766
27210.13.0.0/17210.13.0.1 to 210.13.127.254210.13.127.25532,766
28210.13.128.0/17210.13.128.1 to 210.13.255.254210.13.255.25532,766
29210.14.0.0/17210.14.0.1 to 210.14.127.254210.14.127.25532,766
30210.14.128.0/17210.14.128.1 to 210.14.255.254210.14.255.25532,766
31210.15.0.0/17210.15.0.1 to 210.15.127.254210.15.127.25532,766
32210.15.128.0/17210.15.128.1 to 210.15.255.254210.15.255.25532,766
33210.16.0.0/17210.16.0.1 to 210.16.127.254210.16.127.25532,766
34210.16.128.0/17210.16.128.1 to 210.16.255.254210.16.255.25532,766
35210.17.0.0/17210.17.0.1 to 210.17.127.254210.17.127.25532,766
36210.17.128.0/17210.17.128.1 to 210.17.255.254210.17.255.25532,766
37210.18.0.0/17210.18.0.1 to 210.18.127.254210.18.127.25532,766
38210.18.128.0/17210.18.128.1 to 210.18.255.254210.18.255.25532,766
39210.19.0.0/17210.19.0.1 to 210.19.127.254210.19.127.25532,766
40210.19.128.0/17210.19.128.1 to 210.19.255.254210.19.255.25532,766
41210.20.0.0/17210.20.0.1 to 210.20.127.254210.20.127.25532,766
42210.20.128.0/17210.20.128.1 to 210.20.255.254210.20.255.25532,766
43210.21.0.0/17210.21.0.1 to 210.21.127.254210.21.127.25532,766
44210.21.128.0/17210.21.128.1 to 210.21.255.254210.21.255.25532,766
45210.22.0.0/17210.22.0.1 to 210.22.127.254210.22.127.25532,766
46210.22.128.0/17210.22.128.1 to 210.22.255.254210.22.255.25532,766
47210.23.0.0/17210.23.0.1 to 210.23.127.254210.23.127.25532,766
48210.23.128.0/17210.23.128.1 to 210.23.255.254210.23.255.25532,766
49210.24.0.0/17210.24.0.1 to 210.24.127.254210.24.127.25532,766
50210.24.128.0/17210.24.128.1 to 210.24.255.254210.24.255.25532,766
51210.25.0.0/17210.25.0.1 to 210.25.127.254210.25.127.25532,766
52210.25.128.0/17210.25.128.1 to 210.25.255.254210.25.255.25532,766
53210.26.0.0/17210.26.0.1 to 210.26.127.254210.26.127.25532,766
54210.26.128.0/17210.26.128.1 to 210.26.255.254210.26.255.25532,766
55210.27.0.0/17210.27.0.1 to 210.27.127.254210.27.127.25532,766
56210.27.128.0/17210.27.128.1 to 210.27.255.254210.27.255.25532,766
57210.28.0.0/17210.28.0.1 to 210.28.127.254210.28.127.25532,766
58210.28.128.0/17210.28.128.1 to 210.28.255.254210.28.255.25532,766
59210.29.0.0/17210.29.0.1 to 210.29.127.254210.29.127.25532,766
60210.29.128.0/17210.29.128.1 to 210.29.255.254210.29.255.25532,766
61210.30.0.0/17210.30.0.1 to 210.30.127.254210.30.127.25532,766
62210.30.128.0/17210.30.128.1 to 210.30.255.254210.30.255.25532,766
63210.31.0.0/17210.31.0.1 to 210.31.127.254210.31.127.25532,766
64210.31.128.0/17210.31.128.1 to 210.31.255.254210.31.255.25532,766
65210.32.0.0/17210.32.0.1 to 210.32.127.254210.32.127.25532,766
66210.32.128.0/17210.32.128.1 to 210.32.255.254210.32.255.25532,766
67210.33.0.0/17210.33.0.1 to 210.33.127.254210.33.127.25532,766
68210.33.128.0/17210.33.128.1 to 210.33.255.254210.33.255.25532,766
69210.34.0.0/17210.34.0.1 to 210.34.127.254210.34.127.25532,766
70210.34.128.0/17210.34.128.1 to 210.34.255.254210.34.255.25532,766
71210.35.0.0/17210.35.0.1 to 210.35.127.254210.35.127.25532,766
72210.35.128.0/17210.35.128.1 to 210.35.255.254210.35.255.25532,766
73210.36.0.0/17210.36.0.1 to 210.36.127.254210.36.127.25532,766
74210.36.128.0/17210.36.128.1 to 210.36.255.254210.36.255.25532,766
75210.37.0.0/17210.37.0.1 to 210.37.127.254210.37.127.25532,766
76210.37.128.0/17210.37.128.1 to 210.37.255.254210.37.255.25532,766
77210.38.0.0/17210.38.0.1 to 210.38.127.254210.38.127.25532,766
78210.38.128.0/17210.38.128.1 to 210.38.255.254210.38.255.25532,766
79210.39.0.0/17210.39.0.1 to 210.39.127.254210.39.127.25532,766
80210.39.128.0/17210.39.128.1 to 210.39.255.254210.39.255.25532,766
81210.40.0.0/17210.40.0.1 to 210.40.127.254210.40.127.25532,766
82210.40.128.0/17210.40.128.1 to 210.40.255.254210.40.255.25532,766
83210.41.0.0/17210.41.0.1 to 210.41.127.254210.41.127.25532,766
84210.41.128.0/17210.41.128.1 to 210.41.255.254210.41.255.25532,766
85210.42.0.0/17210.42.0.1 to 210.42.127.254210.42.127.25532,766
86210.42.128.0/17210.42.128.1 to 210.42.255.254210.42.255.25532,766
87210.43.0.0/17210.43.0.1 to 210.43.127.254210.43.127.25532,766
88210.43.128.0/17210.43.128.1 to 210.43.255.254210.43.255.25532,766
89210.44.0.0/17210.44.0.1 to 210.44.127.254210.44.127.25532,766
90210.44.128.0/17210.44.128.1 to 210.44.255.254210.44.255.25532,766
91210.45.0.0/17210.45.0.1 to 210.45.127.254210.45.127.25532,766
92210.45.128.0/17210.45.128.1 to 210.45.255.254210.45.255.25532,766
93210.46.0.0/17210.46.0.1 to 210.46.127.254210.46.127.25532,766
94210.46.128.0/17210.46.128.1 to 210.46.255.254210.46.255.25532,766
95210.47.0.0/17210.47.0.1 to 210.47.127.254210.47.127.25532,766
96210.47.128.0/17210.47.128.1 to 210.47.255.254210.47.255.25532,766
97210.48.0.0/17210.48.0.1 to 210.48.127.254210.48.127.25532,766
98210.48.128.0/17210.48.128.1 to 210.48.255.254210.48.255.25532,766
99210.49.0.0/17210.49.0.1 to 210.49.127.254210.49.127.25532,766
100210.49.128.0/17210.49.128.1 to 210.49.255.254210.49.255.25532,766
101210.50.0.0/17210.50.0.1 to 210.50.127.254210.50.127.25532,766
102210.50.128.0/17210.50.128.1 to 210.50.255.254210.50.255.25532,766
103210.51.0.0/17210.51.0.1 to 210.51.127.254210.51.127.25532,766
104210.51.128.0/17210.51.128.1 to 210.51.255.254210.51.255.25532,766
105210.52.0.0/17210.52.0.1 to 210.52.127.254210.52.127.25532,766
106210.52.128.0/17210.52.128.1 to 210.52.255.254210.52.255.25532,766
107210.53.0.0/17210.53.0.1 to 210.53.127.254210.53.127.25532,766
108210.53.128.0/17210.53.128.1 to 210.53.255.254210.53.255.25532,766
109210.54.0.0/17210.54.0.1 to 210.54.127.254210.54.127.25532,766
110210.54.128.0/17210.54.128.1 to 210.54.255.254210.54.255.25532,766
111210.55.0.0/17210.55.0.1 to 210.55.127.254210.55.127.25532,766
112210.55.128.0/17210.55.128.1 to 210.55.255.254210.55.255.25532,766
113210.56.0.0/17210.56.0.1 to 210.56.127.254210.56.127.25532,766
114210.56.128.0/17210.56.128.1 to 210.56.255.254210.56.255.25532,766
115210.57.0.0/17210.57.0.1 to 210.57.127.254210.57.127.25532,766
116210.57.128.0/17210.57.128.1 to 210.57.255.254210.57.255.25532,766
117210.58.0.0/17210.58.0.1 to 210.58.127.254210.58.127.25532,766
118210.58.128.0/17210.58.128.1 to 210.58.255.254210.58.255.25532,766
119210.59.0.0/17210.59.0.1 to 210.59.127.254210.59.127.25532,766
120210.59.128.0/17210.59.128.1 to 210.59.255.254210.59.255.25532,766
121210.60.0.0/17210.60.0.1 to 210.60.127.254210.60.127.25532,766
122210.60.128.0/17210.60.128.1 to 210.60.255.254210.60.255.25532,766
123210.61.0.0/17210.61.0.1 to 210.61.127.254210.61.127.25532,766
124210.61.128.0/17210.61.128.1 to 210.61.255.254210.61.255.25532,766
125210.62.0.0/17210.62.0.1 to 210.62.127.254210.62.127.25532,766
126210.62.128.0/17210.62.128.1 to 210.62.255.254210.62.255.25532,766
127210.63.0.0/17210.63.0.1 to 210.63.127.254210.63.127.25532,766
128210.63.128.0/17210.63.128.1 to 210.63.255.254210.63.255.25532,766
129210.64.0.0/17210.64.0.1 to 210.64.127.254210.64.127.25532,766
130210.64.128.0/17210.64.128.1 to 210.64.255.254210.64.255.25532,766
131210.65.0.0/17210.65.0.1 to 210.65.127.254210.65.127.25532,766
132210.65.128.0/17210.65.128.1 to 210.65.255.254210.65.255.25532,766
133210.66.0.0/17210.66.0.1 to 210.66.127.254210.66.127.25532,766
134210.66.128.0/17210.66.128.1 to 210.66.255.254210.66.255.25532,766
135210.67.0.0/17210.67.0.1 to 210.67.127.254210.67.127.25532,766
136210.67.128.0/17210.67.128.1 to 210.67.255.254210.67.255.25532,766
137210.68.0.0/17210.68.0.1 to 210.68.127.254210.68.127.25532,766
138210.68.128.0/17210.68.128.1 to 210.68.255.254210.68.255.25532,766
139210.69.0.0/17210.69.0.1 to 210.69.127.254210.69.127.25532,766
140210.69.128.0/17210.69.128.1 to 210.69.255.254210.69.255.25532,766
141210.70.0.0/17210.70.0.1 to 210.70.127.254210.70.127.25532,766
142210.70.128.0/17210.70.128.1 to 210.70.255.254210.70.255.25532,766
143210.71.0.0/17210.71.0.1 to 210.71.127.254210.71.127.25532,766
144210.71.128.0/17210.71.128.1 to 210.71.255.254210.71.255.25532,766
145210.72.0.0/17210.72.0.1 to 210.72.127.254210.72.127.25532,766
146210.72.128.0/17210.72.128.1 to 210.72.255.254210.72.255.25532,766
147210.73.0.0/17210.73.0.1 to 210.73.127.254210.73.127.25532,766
148210.73.128.0/17210.73.128.1 to 210.73.255.254210.73.255.25532,766
149210.74.0.0/17210.74.0.1 to 210.74.127.254210.74.127.25532,766
150210.74.128.0/17210.74.128.1 to 210.74.255.254210.74.255.25532,766
151210.75.0.0/17210.75.0.1 to 210.75.127.254210.75.127.25532,766
152210.75.128.0/17210.75.128.1 to 210.75.255.254210.75.255.25532,766
153210.76.0.0/17210.76.0.1 to 210.76.127.254210.76.127.25532,766
154210.76.128.0/17210.76.128.1 to 210.76.255.254210.76.255.25532,766
155210.77.0.0/17210.77.0.1 to 210.77.127.254210.77.127.25532,766
156210.77.128.0/17210.77.128.1 to 210.77.255.254210.77.255.25532,766
157210.78.0.0/17210.78.0.1 to 210.78.127.254210.78.127.25532,766
158210.78.128.0/17210.78.128.1 to 210.78.255.254210.78.255.25532,766
159210.79.0.0/17210.79.0.1 to 210.79.127.254210.79.127.25532,766
160210.79.128.0/17210.79.128.1 to 210.79.255.254210.79.255.25532,766
161210.80.0.0/17210.80.0.1 to 210.80.127.254210.80.127.25532,766
162210.80.128.0/17210.80.128.1 to 210.80.255.254210.80.255.25532,766
163210.81.0.0/17210.81.0.1 to 210.81.127.254210.81.127.25532,766
164210.81.128.0/17210.81.128.1 to 210.81.255.254210.81.255.25532,766
165210.82.0.0/17210.82.0.1 to 210.82.127.254210.82.127.25532,766
166210.82.128.0/17210.82.128.1 to 210.82.255.254210.82.255.25532,766
167210.83.0.0/17210.83.0.1 to 210.83.127.254210.83.127.25532,766
168210.83.128.0/17210.83.128.1 to 210.83.255.254210.83.255.25532,766
169210.84.0.0/17210.84.0.1 to 210.84.127.254210.84.127.25532,766
170210.84.128.0/17210.84.128.1 to 210.84.255.254210.84.255.25532,766
171210.85.0.0/17210.85.0.1 to 210.85.127.254210.85.127.25532,766
172210.85.128.0/17210.85.128.1 to 210.85.255.254210.85.255.25532,766
173210.86.0.0/17210.86.0.1 to 210.86.127.254210.86.127.25532,766
174210.86.128.0/17210.86.128.1 to 210.86.255.254210.86.255.25532,766
175210.87.0.0/17210.87.0.1 to 210.87.127.254210.87.127.25532,766
176210.87.128.0/17210.87.128.1 to 210.87.255.254210.87.255.25532,766
177210.88.0.0/17210.88.0.1 to 210.88.127.254210.88.127.25532,766
178210.88.128.0/17210.88.128.1 to 210.88.255.254210.88.255.25532,766
179210.89.0.0/17210.89.0.1 to 210.89.127.254210.89.127.25532,766
180210.89.128.0/17210.89.128.1 to 210.89.255.254210.89.255.25532,766
181210.90.0.0/17210.90.0.1 to 210.90.127.254210.90.127.25532,766
182210.90.128.0/17210.90.128.1 to 210.90.255.254210.90.255.25532,766
183210.91.0.0/17210.91.0.1 to 210.91.127.254210.91.127.25532,766
184210.91.128.0/17210.91.128.1 to 210.91.255.254210.91.255.25532,766
185210.92.0.0/17210.92.0.1 to 210.92.127.254210.92.127.25532,766
186210.92.128.0/17210.92.128.1 to 210.92.255.254210.92.255.25532,766
187210.93.0.0/17210.93.0.1 to 210.93.127.254210.93.127.25532,766
188210.93.128.0/17210.93.128.1 to 210.93.255.254210.93.255.25532,766
189210.94.0.0/17210.94.0.1 to 210.94.127.254210.94.127.25532,766
190210.94.128.0/17210.94.128.1 to 210.94.255.254210.94.255.25532,766
191210.95.0.0/17210.95.0.1 to 210.95.127.254210.95.127.25532,766
192210.95.128.0/17210.95.128.1 to 210.95.255.254210.95.255.25532,766
193210.96.0.0/17210.96.0.1 to 210.96.127.254210.96.127.25532,766
194210.96.128.0/17210.96.128.1 to 210.96.255.254210.96.255.25532,766
195210.97.0.0/17210.97.0.1 to 210.97.127.254210.97.127.25532,766
196210.97.128.0/17210.97.128.1 to 210.97.255.254210.97.255.25532,766
197210.98.0.0/17210.98.0.1 to 210.98.127.254210.98.127.25532,766
198210.98.128.0/17210.98.128.1 to 210.98.255.254210.98.255.25532,766
199210.99.0.0/17210.99.0.1 to 210.99.127.254210.99.127.25532,766
200210.99.128.0/17210.99.128.1 to 210.99.255.254210.99.255.25532,766
201210.100.0.0/17210.100.0.1 to 210.100.127.254210.100.127.25532,766
202210.100.128.0/17210.100.128.1 to 210.100.255.254210.100.255.25532,766
203210.101.0.0/17210.101.0.1 to 210.101.127.254210.101.127.25532,766
204210.101.128.0/17210.101.128.1 to 210.101.255.254210.101.255.25532,766
205210.102.0.0/17210.102.0.1 to 210.102.127.254210.102.127.25532,766
206210.102.128.0/17210.102.128.1 to 210.102.255.254210.102.255.25532,766
207210.103.0.0/17210.103.0.1 to 210.103.127.254210.103.127.25532,766
208210.103.128.0/17210.103.128.1 to 210.103.255.254210.103.255.25532,766
209210.104.0.0/17210.104.0.1 to 210.104.127.254210.104.127.25532,766
210210.104.128.0/17210.104.128.1 to 210.104.255.254210.104.255.25532,766
211210.105.0.0/17210.105.0.1 to 210.105.127.254210.105.127.25532,766
212210.105.128.0/17210.105.128.1 to 210.105.255.254210.105.255.25532,766
213210.106.0.0/17210.106.0.1 to 210.106.127.254210.106.127.25532,766
214210.106.128.0/17210.106.128.1 to 210.106.255.254210.106.255.25532,766
215210.107.0.0/17210.107.0.1 to 210.107.127.254210.107.127.25532,766
216210.107.128.0/17210.107.128.1 to 210.107.255.254210.107.255.25532,766
217210.108.0.0/17210.108.0.1 to 210.108.127.254210.108.127.25532,766
218210.108.128.0/17210.108.128.1 to 210.108.255.254210.108.255.25532,766
219210.109.0.0/17210.109.0.1 to 210.109.127.254210.109.127.25532,766
220210.109.128.0/17210.109.128.1 to 210.109.255.254210.109.255.25532,766
221210.110.0.0/17210.110.0.1 to 210.110.127.254210.110.127.25532,766
222210.110.128.0/17210.110.128.1 to 210.110.255.254210.110.255.25532,766
223210.111.0.0/17210.111.0.1 to 210.111.127.254210.111.127.25532,766
224210.111.128.0/17210.111.128.1 to 210.111.255.254210.111.255.25532,766
225210.112.0.0/17210.112.0.1 to 210.112.127.254210.112.127.25532,766
226210.112.128.0/17210.112.128.1 to 210.112.255.254210.112.255.25532,766
227210.113.0.0/17210.113.0.1 to 210.113.127.254210.113.127.25532,766
228210.113.128.0/17210.113.128.1 to 210.113.255.254210.113.255.25532,766
229210.114.0.0/17210.114.0.1 to 210.114.127.254210.114.127.25532,766
230210.114.128.0/17210.114.128.1 to 210.114.255.254210.114.255.25532,766
231210.115.0.0/17210.115.0.1 to 210.115.127.254210.115.127.25532,766
232210.115.128.0/17210.115.128.1 to 210.115.255.254210.115.255.25532,766
233210.116.0.0/17210.116.0.1 to 210.116.127.254210.116.127.25532,766
234210.116.128.0/17210.116.128.1 to 210.116.255.254210.116.255.25532,766
235210.117.0.0/17210.117.0.1 to 210.117.127.254210.117.127.25532,766
236210.117.128.0/17210.117.128.1 to 210.117.255.254210.117.255.25532,766
237210.118.0.0/17210.118.0.1 to 210.118.127.254210.118.127.25532,766
238210.118.128.0/17210.118.128.1 to 210.118.255.254210.118.255.25532,766
239210.119.0.0/17210.119.0.1 to 210.119.127.254210.119.127.25532,766
240210.119.128.0/17210.119.128.1 to 210.119.255.254210.119.255.25532,766
241210.120.0.0/17210.120.0.1 to 210.120.127.254210.120.127.25532,766
242210.120.128.0/17210.120.128.1 to 210.120.255.254210.120.255.25532,766
243210.121.0.0/17210.121.0.1 to 210.121.127.254210.121.127.25532,766
244210.121.128.0/17210.121.128.1 to 210.121.255.254210.121.255.25532,766
245210.122.0.0/17210.122.0.1 to 210.122.127.254210.122.127.25532,766
246210.122.128.0/17210.122.128.1 to 210.122.255.254210.122.255.25532,766
247210.123.0.0/17210.123.0.1 to 210.123.127.254210.123.127.25532,766
248210.123.128.0/17210.123.128.1 to 210.123.255.254210.123.255.25532,766
249210.124.0.0/17210.124.0.1 to 210.124.127.254210.124.127.25532,766
250210.124.128.0/17210.124.128.1 to 210.124.255.254210.124.255.25532,766
251210.125.0.0/17210.125.0.1 to 210.125.127.254210.125.127.25532,766
252210.125.128.0/17210.125.128.1 to 210.125.255.254210.125.255.25532,766
253210.126.0.0/17210.126.0.1 to 210.126.127.254210.126.127.25532,766
254210.126.128.0/17210.126.128.1 to 210.126.255.254210.126.255.25532,766
255210.127.0.0/17210.127.0.1 to 210.127.127.254210.127.127.25532,766
256210.127.128.0/17210.127.128.1 to 210.127.255.254210.127.255.25532,766

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.