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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.

Network211.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
211.0.0.0
Broadcast address
211.255.255.255
First usable
211.0.0.1
Last usable
211.255.255.254
Usable hosts
16,777,214 (16,777,216 less the network and broadcast addresses)
Subnet mask
255.0.0.0
Wildcard mask
0.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/8
Type
Public public
Old class
C (default /24)
As numbers
Hex D3000000 · Integer 3539992576 to 3556769791
Reverse DNS zone
211.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11010011..00000000.00000000.00000000211.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network11010011..00000000.00000000.00000000211.0.0.0
Broadcast11010011..11111111.11111111.11111111211.255.255.255
Split into smaller subnets/17
/9 (2)/10 (4)/11 (8)/12 (16)/13 (32)/14 (64)/15 (128)/16 (256)/17 (512)/18 (1,024)/19 (2,048)/20 (4,096)

211.0.0.0/8 makes 512 subnets of /17; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1211.0.0.0/17211.0.0.1 to 211.0.127.254211.0.127.25532,766
2211.0.128.0/17211.0.128.1 to 211.0.255.254211.0.255.25532,766
3211.1.0.0/17211.1.0.1 to 211.1.127.254211.1.127.25532,766
4211.1.128.0/17211.1.128.1 to 211.1.255.254211.1.255.25532,766
5211.2.0.0/17211.2.0.1 to 211.2.127.254211.2.127.25532,766
6211.2.128.0/17211.2.128.1 to 211.2.255.254211.2.255.25532,766
7211.3.0.0/17211.3.0.1 to 211.3.127.254211.3.127.25532,766
8211.3.128.0/17211.3.128.1 to 211.3.255.254211.3.255.25532,766
9211.4.0.0/17211.4.0.1 to 211.4.127.254211.4.127.25532,766
10211.4.128.0/17211.4.128.1 to 211.4.255.254211.4.255.25532,766
11211.5.0.0/17211.5.0.1 to 211.5.127.254211.5.127.25532,766
12211.5.128.0/17211.5.128.1 to 211.5.255.254211.5.255.25532,766
13211.6.0.0/17211.6.0.1 to 211.6.127.254211.6.127.25532,766
14211.6.128.0/17211.6.128.1 to 211.6.255.254211.6.255.25532,766
15211.7.0.0/17211.7.0.1 to 211.7.127.254211.7.127.25532,766
16211.7.128.0/17211.7.128.1 to 211.7.255.254211.7.255.25532,766
17211.8.0.0/17211.8.0.1 to 211.8.127.254211.8.127.25532,766
18211.8.128.0/17211.8.128.1 to 211.8.255.254211.8.255.25532,766
19211.9.0.0/17211.9.0.1 to 211.9.127.254211.9.127.25532,766
20211.9.128.0/17211.9.128.1 to 211.9.255.254211.9.255.25532,766
21211.10.0.0/17211.10.0.1 to 211.10.127.254211.10.127.25532,766
22211.10.128.0/17211.10.128.1 to 211.10.255.254211.10.255.25532,766
23211.11.0.0/17211.11.0.1 to 211.11.127.254211.11.127.25532,766
24211.11.128.0/17211.11.128.1 to 211.11.255.254211.11.255.25532,766
25211.12.0.0/17211.12.0.1 to 211.12.127.254211.12.127.25532,766
26211.12.128.0/17211.12.128.1 to 211.12.255.254211.12.255.25532,766
27211.13.0.0/17211.13.0.1 to 211.13.127.254211.13.127.25532,766
28211.13.128.0/17211.13.128.1 to 211.13.255.254211.13.255.25532,766
29211.14.0.0/17211.14.0.1 to 211.14.127.254211.14.127.25532,766
30211.14.128.0/17211.14.128.1 to 211.14.255.254211.14.255.25532,766
31211.15.0.0/17211.15.0.1 to 211.15.127.254211.15.127.25532,766
32211.15.128.0/17211.15.128.1 to 211.15.255.254211.15.255.25532,766
33211.16.0.0/17211.16.0.1 to 211.16.127.254211.16.127.25532,766
34211.16.128.0/17211.16.128.1 to 211.16.255.254211.16.255.25532,766
35211.17.0.0/17211.17.0.1 to 211.17.127.254211.17.127.25532,766
36211.17.128.0/17211.17.128.1 to 211.17.255.254211.17.255.25532,766
37211.18.0.0/17211.18.0.1 to 211.18.127.254211.18.127.25532,766
38211.18.128.0/17211.18.128.1 to 211.18.255.254211.18.255.25532,766
39211.19.0.0/17211.19.0.1 to 211.19.127.254211.19.127.25532,766
40211.19.128.0/17211.19.128.1 to 211.19.255.254211.19.255.25532,766
41211.20.0.0/17211.20.0.1 to 211.20.127.254211.20.127.25532,766
42211.20.128.0/17211.20.128.1 to 211.20.255.254211.20.255.25532,766
43211.21.0.0/17211.21.0.1 to 211.21.127.254211.21.127.25532,766
44211.21.128.0/17211.21.128.1 to 211.21.255.254211.21.255.25532,766
45211.22.0.0/17211.22.0.1 to 211.22.127.254211.22.127.25532,766
46211.22.128.0/17211.22.128.1 to 211.22.255.254211.22.255.25532,766
47211.23.0.0/17211.23.0.1 to 211.23.127.254211.23.127.25532,766
48211.23.128.0/17211.23.128.1 to 211.23.255.254211.23.255.25532,766
49211.24.0.0/17211.24.0.1 to 211.24.127.254211.24.127.25532,766
50211.24.128.0/17211.24.128.1 to 211.24.255.254211.24.255.25532,766
51211.25.0.0/17211.25.0.1 to 211.25.127.254211.25.127.25532,766
52211.25.128.0/17211.25.128.1 to 211.25.255.254211.25.255.25532,766
53211.26.0.0/17211.26.0.1 to 211.26.127.254211.26.127.25532,766
54211.26.128.0/17211.26.128.1 to 211.26.255.254211.26.255.25532,766
55211.27.0.0/17211.27.0.1 to 211.27.127.254211.27.127.25532,766
56211.27.128.0/17211.27.128.1 to 211.27.255.254211.27.255.25532,766
57211.28.0.0/17211.28.0.1 to 211.28.127.254211.28.127.25532,766
58211.28.128.0/17211.28.128.1 to 211.28.255.254211.28.255.25532,766
59211.29.0.0/17211.29.0.1 to 211.29.127.254211.29.127.25532,766
60211.29.128.0/17211.29.128.1 to 211.29.255.254211.29.255.25532,766
61211.30.0.0/17211.30.0.1 to 211.30.127.254211.30.127.25532,766
62211.30.128.0/17211.30.128.1 to 211.30.255.254211.30.255.25532,766
63211.31.0.0/17211.31.0.1 to 211.31.127.254211.31.127.25532,766
64211.31.128.0/17211.31.128.1 to 211.31.255.254211.31.255.25532,766
65211.32.0.0/17211.32.0.1 to 211.32.127.254211.32.127.25532,766
66211.32.128.0/17211.32.128.1 to 211.32.255.254211.32.255.25532,766
67211.33.0.0/17211.33.0.1 to 211.33.127.254211.33.127.25532,766
68211.33.128.0/17211.33.128.1 to 211.33.255.254211.33.255.25532,766
69211.34.0.0/17211.34.0.1 to 211.34.127.254211.34.127.25532,766
70211.34.128.0/17211.34.128.1 to 211.34.255.254211.34.255.25532,766
71211.35.0.0/17211.35.0.1 to 211.35.127.254211.35.127.25532,766
72211.35.128.0/17211.35.128.1 to 211.35.255.254211.35.255.25532,766
73211.36.0.0/17211.36.0.1 to 211.36.127.254211.36.127.25532,766
74211.36.128.0/17211.36.128.1 to 211.36.255.254211.36.255.25532,766
75211.37.0.0/17211.37.0.1 to 211.37.127.254211.37.127.25532,766
76211.37.128.0/17211.37.128.1 to 211.37.255.254211.37.255.25532,766
77211.38.0.0/17211.38.0.1 to 211.38.127.254211.38.127.25532,766
78211.38.128.0/17211.38.128.1 to 211.38.255.254211.38.255.25532,766
79211.39.0.0/17211.39.0.1 to 211.39.127.254211.39.127.25532,766
80211.39.128.0/17211.39.128.1 to 211.39.255.254211.39.255.25532,766
81211.40.0.0/17211.40.0.1 to 211.40.127.254211.40.127.25532,766
82211.40.128.0/17211.40.128.1 to 211.40.255.254211.40.255.25532,766
83211.41.0.0/17211.41.0.1 to 211.41.127.254211.41.127.25532,766
84211.41.128.0/17211.41.128.1 to 211.41.255.254211.41.255.25532,766
85211.42.0.0/17211.42.0.1 to 211.42.127.254211.42.127.25532,766
86211.42.128.0/17211.42.128.1 to 211.42.255.254211.42.255.25532,766
87211.43.0.0/17211.43.0.1 to 211.43.127.254211.43.127.25532,766
88211.43.128.0/17211.43.128.1 to 211.43.255.254211.43.255.25532,766
89211.44.0.0/17211.44.0.1 to 211.44.127.254211.44.127.25532,766
90211.44.128.0/17211.44.128.1 to 211.44.255.254211.44.255.25532,766
91211.45.0.0/17211.45.0.1 to 211.45.127.254211.45.127.25532,766
92211.45.128.0/17211.45.128.1 to 211.45.255.254211.45.255.25532,766
93211.46.0.0/17211.46.0.1 to 211.46.127.254211.46.127.25532,766
94211.46.128.0/17211.46.128.1 to 211.46.255.254211.46.255.25532,766
95211.47.0.0/17211.47.0.1 to 211.47.127.254211.47.127.25532,766
96211.47.128.0/17211.47.128.1 to 211.47.255.254211.47.255.25532,766
97211.48.0.0/17211.48.0.1 to 211.48.127.254211.48.127.25532,766
98211.48.128.0/17211.48.128.1 to 211.48.255.254211.48.255.25532,766
99211.49.0.0/17211.49.0.1 to 211.49.127.254211.49.127.25532,766
100211.49.128.0/17211.49.128.1 to 211.49.255.254211.49.255.25532,766
101211.50.0.0/17211.50.0.1 to 211.50.127.254211.50.127.25532,766
102211.50.128.0/17211.50.128.1 to 211.50.255.254211.50.255.25532,766
103211.51.0.0/17211.51.0.1 to 211.51.127.254211.51.127.25532,766
104211.51.128.0/17211.51.128.1 to 211.51.255.254211.51.255.25532,766
105211.52.0.0/17211.52.0.1 to 211.52.127.254211.52.127.25532,766
106211.52.128.0/17211.52.128.1 to 211.52.255.254211.52.255.25532,766
107211.53.0.0/17211.53.0.1 to 211.53.127.254211.53.127.25532,766
108211.53.128.0/17211.53.128.1 to 211.53.255.254211.53.255.25532,766
109211.54.0.0/17211.54.0.1 to 211.54.127.254211.54.127.25532,766
110211.54.128.0/17211.54.128.1 to 211.54.255.254211.54.255.25532,766
111211.55.0.0/17211.55.0.1 to 211.55.127.254211.55.127.25532,766
112211.55.128.0/17211.55.128.1 to 211.55.255.254211.55.255.25532,766
113211.56.0.0/17211.56.0.1 to 211.56.127.254211.56.127.25532,766
114211.56.128.0/17211.56.128.1 to 211.56.255.254211.56.255.25532,766
115211.57.0.0/17211.57.0.1 to 211.57.127.254211.57.127.25532,766
116211.57.128.0/17211.57.128.1 to 211.57.255.254211.57.255.25532,766
117211.58.0.0/17211.58.0.1 to 211.58.127.254211.58.127.25532,766
118211.58.128.0/17211.58.128.1 to 211.58.255.254211.58.255.25532,766
119211.59.0.0/17211.59.0.1 to 211.59.127.254211.59.127.25532,766
120211.59.128.0/17211.59.128.1 to 211.59.255.254211.59.255.25532,766
121211.60.0.0/17211.60.0.1 to 211.60.127.254211.60.127.25532,766
122211.60.128.0/17211.60.128.1 to 211.60.255.254211.60.255.25532,766
123211.61.0.0/17211.61.0.1 to 211.61.127.254211.61.127.25532,766
124211.61.128.0/17211.61.128.1 to 211.61.255.254211.61.255.25532,766
125211.62.0.0/17211.62.0.1 to 211.62.127.254211.62.127.25532,766
126211.62.128.0/17211.62.128.1 to 211.62.255.254211.62.255.25532,766
127211.63.0.0/17211.63.0.1 to 211.63.127.254211.63.127.25532,766
128211.63.128.0/17211.63.128.1 to 211.63.255.254211.63.255.25532,766
129211.64.0.0/17211.64.0.1 to 211.64.127.254211.64.127.25532,766
130211.64.128.0/17211.64.128.1 to 211.64.255.254211.64.255.25532,766
131211.65.0.0/17211.65.0.1 to 211.65.127.254211.65.127.25532,766
132211.65.128.0/17211.65.128.1 to 211.65.255.254211.65.255.25532,766
133211.66.0.0/17211.66.0.1 to 211.66.127.254211.66.127.25532,766
134211.66.128.0/17211.66.128.1 to 211.66.255.254211.66.255.25532,766
135211.67.0.0/17211.67.0.1 to 211.67.127.254211.67.127.25532,766
136211.67.128.0/17211.67.128.1 to 211.67.255.254211.67.255.25532,766
137211.68.0.0/17211.68.0.1 to 211.68.127.254211.68.127.25532,766
138211.68.128.0/17211.68.128.1 to 211.68.255.254211.68.255.25532,766
139211.69.0.0/17211.69.0.1 to 211.69.127.254211.69.127.25532,766
140211.69.128.0/17211.69.128.1 to 211.69.255.254211.69.255.25532,766
141211.70.0.0/17211.70.0.1 to 211.70.127.254211.70.127.25532,766
142211.70.128.0/17211.70.128.1 to 211.70.255.254211.70.255.25532,766
143211.71.0.0/17211.71.0.1 to 211.71.127.254211.71.127.25532,766
144211.71.128.0/17211.71.128.1 to 211.71.255.254211.71.255.25532,766
145211.72.0.0/17211.72.0.1 to 211.72.127.254211.72.127.25532,766
146211.72.128.0/17211.72.128.1 to 211.72.255.254211.72.255.25532,766
147211.73.0.0/17211.73.0.1 to 211.73.127.254211.73.127.25532,766
148211.73.128.0/17211.73.128.1 to 211.73.255.254211.73.255.25532,766
149211.74.0.0/17211.74.0.1 to 211.74.127.254211.74.127.25532,766
150211.74.128.0/17211.74.128.1 to 211.74.255.254211.74.255.25532,766
151211.75.0.0/17211.75.0.1 to 211.75.127.254211.75.127.25532,766
152211.75.128.0/17211.75.128.1 to 211.75.255.254211.75.255.25532,766
153211.76.0.0/17211.76.0.1 to 211.76.127.254211.76.127.25532,766
154211.76.128.0/17211.76.128.1 to 211.76.255.254211.76.255.25532,766
155211.77.0.0/17211.77.0.1 to 211.77.127.254211.77.127.25532,766
156211.77.128.0/17211.77.128.1 to 211.77.255.254211.77.255.25532,766
157211.78.0.0/17211.78.0.1 to 211.78.127.254211.78.127.25532,766
158211.78.128.0/17211.78.128.1 to 211.78.255.254211.78.255.25532,766
159211.79.0.0/17211.79.0.1 to 211.79.127.254211.79.127.25532,766
160211.79.128.0/17211.79.128.1 to 211.79.255.254211.79.255.25532,766
161211.80.0.0/17211.80.0.1 to 211.80.127.254211.80.127.25532,766
162211.80.128.0/17211.80.128.1 to 211.80.255.254211.80.255.25532,766
163211.81.0.0/17211.81.0.1 to 211.81.127.254211.81.127.25532,766
164211.81.128.0/17211.81.128.1 to 211.81.255.254211.81.255.25532,766
165211.82.0.0/17211.82.0.1 to 211.82.127.254211.82.127.25532,766
166211.82.128.0/17211.82.128.1 to 211.82.255.254211.82.255.25532,766
167211.83.0.0/17211.83.0.1 to 211.83.127.254211.83.127.25532,766
168211.83.128.0/17211.83.128.1 to 211.83.255.254211.83.255.25532,766
169211.84.0.0/17211.84.0.1 to 211.84.127.254211.84.127.25532,766
170211.84.128.0/17211.84.128.1 to 211.84.255.254211.84.255.25532,766
171211.85.0.0/17211.85.0.1 to 211.85.127.254211.85.127.25532,766
172211.85.128.0/17211.85.128.1 to 211.85.255.254211.85.255.25532,766
173211.86.0.0/17211.86.0.1 to 211.86.127.254211.86.127.25532,766
174211.86.128.0/17211.86.128.1 to 211.86.255.254211.86.255.25532,766
175211.87.0.0/17211.87.0.1 to 211.87.127.254211.87.127.25532,766
176211.87.128.0/17211.87.128.1 to 211.87.255.254211.87.255.25532,766
177211.88.0.0/17211.88.0.1 to 211.88.127.254211.88.127.25532,766
178211.88.128.0/17211.88.128.1 to 211.88.255.254211.88.255.25532,766
179211.89.0.0/17211.89.0.1 to 211.89.127.254211.89.127.25532,766
180211.89.128.0/17211.89.128.1 to 211.89.255.254211.89.255.25532,766
181211.90.0.0/17211.90.0.1 to 211.90.127.254211.90.127.25532,766
182211.90.128.0/17211.90.128.1 to 211.90.255.254211.90.255.25532,766
183211.91.0.0/17211.91.0.1 to 211.91.127.254211.91.127.25532,766
184211.91.128.0/17211.91.128.1 to 211.91.255.254211.91.255.25532,766
185211.92.0.0/17211.92.0.1 to 211.92.127.254211.92.127.25532,766
186211.92.128.0/17211.92.128.1 to 211.92.255.254211.92.255.25532,766
187211.93.0.0/17211.93.0.1 to 211.93.127.254211.93.127.25532,766
188211.93.128.0/17211.93.128.1 to 211.93.255.254211.93.255.25532,766
189211.94.0.0/17211.94.0.1 to 211.94.127.254211.94.127.25532,766
190211.94.128.0/17211.94.128.1 to 211.94.255.254211.94.255.25532,766
191211.95.0.0/17211.95.0.1 to 211.95.127.254211.95.127.25532,766
192211.95.128.0/17211.95.128.1 to 211.95.255.254211.95.255.25532,766
193211.96.0.0/17211.96.0.1 to 211.96.127.254211.96.127.25532,766
194211.96.128.0/17211.96.128.1 to 211.96.255.254211.96.255.25532,766
195211.97.0.0/17211.97.0.1 to 211.97.127.254211.97.127.25532,766
196211.97.128.0/17211.97.128.1 to 211.97.255.254211.97.255.25532,766
197211.98.0.0/17211.98.0.1 to 211.98.127.254211.98.127.25532,766
198211.98.128.0/17211.98.128.1 to 211.98.255.254211.98.255.25532,766
199211.99.0.0/17211.99.0.1 to 211.99.127.254211.99.127.25532,766
200211.99.128.0/17211.99.128.1 to 211.99.255.254211.99.255.25532,766
201211.100.0.0/17211.100.0.1 to 211.100.127.254211.100.127.25532,766
202211.100.128.0/17211.100.128.1 to 211.100.255.254211.100.255.25532,766
203211.101.0.0/17211.101.0.1 to 211.101.127.254211.101.127.25532,766
204211.101.128.0/17211.101.128.1 to 211.101.255.254211.101.255.25532,766
205211.102.0.0/17211.102.0.1 to 211.102.127.254211.102.127.25532,766
206211.102.128.0/17211.102.128.1 to 211.102.255.254211.102.255.25532,766
207211.103.0.0/17211.103.0.1 to 211.103.127.254211.103.127.25532,766
208211.103.128.0/17211.103.128.1 to 211.103.255.254211.103.255.25532,766
209211.104.0.0/17211.104.0.1 to 211.104.127.254211.104.127.25532,766
210211.104.128.0/17211.104.128.1 to 211.104.255.254211.104.255.25532,766
211211.105.0.0/17211.105.0.1 to 211.105.127.254211.105.127.25532,766
212211.105.128.0/17211.105.128.1 to 211.105.255.254211.105.255.25532,766
213211.106.0.0/17211.106.0.1 to 211.106.127.254211.106.127.25532,766
214211.106.128.0/17211.106.128.1 to 211.106.255.254211.106.255.25532,766
215211.107.0.0/17211.107.0.1 to 211.107.127.254211.107.127.25532,766
216211.107.128.0/17211.107.128.1 to 211.107.255.254211.107.255.25532,766
217211.108.0.0/17211.108.0.1 to 211.108.127.254211.108.127.25532,766
218211.108.128.0/17211.108.128.1 to 211.108.255.254211.108.255.25532,766
219211.109.0.0/17211.109.0.1 to 211.109.127.254211.109.127.25532,766
220211.109.128.0/17211.109.128.1 to 211.109.255.254211.109.255.25532,766
221211.110.0.0/17211.110.0.1 to 211.110.127.254211.110.127.25532,766
222211.110.128.0/17211.110.128.1 to 211.110.255.254211.110.255.25532,766
223211.111.0.0/17211.111.0.1 to 211.111.127.254211.111.127.25532,766
224211.111.128.0/17211.111.128.1 to 211.111.255.254211.111.255.25532,766
225211.112.0.0/17211.112.0.1 to 211.112.127.254211.112.127.25532,766
226211.112.128.0/17211.112.128.1 to 211.112.255.254211.112.255.25532,766
227211.113.0.0/17211.113.0.1 to 211.113.127.254211.113.127.25532,766
228211.113.128.0/17211.113.128.1 to 211.113.255.254211.113.255.25532,766
229211.114.0.0/17211.114.0.1 to 211.114.127.254211.114.127.25532,766
230211.114.128.0/17211.114.128.1 to 211.114.255.254211.114.255.25532,766
231211.115.0.0/17211.115.0.1 to 211.115.127.254211.115.127.25532,766
232211.115.128.0/17211.115.128.1 to 211.115.255.254211.115.255.25532,766
233211.116.0.0/17211.116.0.1 to 211.116.127.254211.116.127.25532,766
234211.116.128.0/17211.116.128.1 to 211.116.255.254211.116.255.25532,766
235211.117.0.0/17211.117.0.1 to 211.117.127.254211.117.127.25532,766
236211.117.128.0/17211.117.128.1 to 211.117.255.254211.117.255.25532,766
237211.118.0.0/17211.118.0.1 to 211.118.127.254211.118.127.25532,766
238211.118.128.0/17211.118.128.1 to 211.118.255.254211.118.255.25532,766
239211.119.0.0/17211.119.0.1 to 211.119.127.254211.119.127.25532,766
240211.119.128.0/17211.119.128.1 to 211.119.255.254211.119.255.25532,766
241211.120.0.0/17211.120.0.1 to 211.120.127.254211.120.127.25532,766
242211.120.128.0/17211.120.128.1 to 211.120.255.254211.120.255.25532,766
243211.121.0.0/17211.121.0.1 to 211.121.127.254211.121.127.25532,766
244211.121.128.0/17211.121.128.1 to 211.121.255.254211.121.255.25532,766
245211.122.0.0/17211.122.0.1 to 211.122.127.254211.122.127.25532,766
246211.122.128.0/17211.122.128.1 to 211.122.255.254211.122.255.25532,766
247211.123.0.0/17211.123.0.1 to 211.123.127.254211.123.127.25532,766
248211.123.128.0/17211.123.128.1 to 211.123.255.254211.123.255.25532,766
249211.124.0.0/17211.124.0.1 to 211.124.127.254211.124.127.25532,766
250211.124.128.0/17211.124.128.1 to 211.124.255.254211.124.255.25532,766
251211.125.0.0/17211.125.0.1 to 211.125.127.254211.125.127.25532,766
252211.125.128.0/17211.125.128.1 to 211.125.255.254211.125.255.25532,766
253211.126.0.0/17211.126.0.1 to 211.126.127.254211.126.127.25532,766
254211.126.128.0/17211.126.128.1 to 211.126.255.254211.126.255.25532,766
255211.127.0.0/17211.127.0.1 to 211.127.127.254211.127.127.25532,766
256211.127.128.0/17211.127.128.1 to 211.127.255.254211.127.255.25532,766

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.