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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.

Network219.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
219.0.0.0
Broadcast address
219.255.255.255
First usable
219.0.0.1
Last usable
219.255.255.254
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 DB000000 · Integer 3674210304 to 3690987519
Reverse DNS zone
219.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11011011..00000000.00000000.00000000219.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network11011011..00000000.00000000.00000000219.0.0.0
Broadcast11011011..11111111.11111111.11111111219.255.255.255
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)

219.0.0.0/8 makes 512 subnets of /17; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1219.0.0.0/17219.0.0.1 to 219.0.127.254219.0.127.25532,766
2219.0.128.0/17219.0.128.1 to 219.0.255.254219.0.255.25532,766
3219.1.0.0/17219.1.0.1 to 219.1.127.254219.1.127.25532,766
4219.1.128.0/17219.1.128.1 to 219.1.255.254219.1.255.25532,766
5219.2.0.0/17219.2.0.1 to 219.2.127.254219.2.127.25532,766
6219.2.128.0/17219.2.128.1 to 219.2.255.254219.2.255.25532,766
7219.3.0.0/17219.3.0.1 to 219.3.127.254219.3.127.25532,766
8219.3.128.0/17219.3.128.1 to 219.3.255.254219.3.255.25532,766
9219.4.0.0/17219.4.0.1 to 219.4.127.254219.4.127.25532,766
10219.4.128.0/17219.4.128.1 to 219.4.255.254219.4.255.25532,766
11219.5.0.0/17219.5.0.1 to 219.5.127.254219.5.127.25532,766
12219.5.128.0/17219.5.128.1 to 219.5.255.254219.5.255.25532,766
13219.6.0.0/17219.6.0.1 to 219.6.127.254219.6.127.25532,766
14219.6.128.0/17219.6.128.1 to 219.6.255.254219.6.255.25532,766
15219.7.0.0/17219.7.0.1 to 219.7.127.254219.7.127.25532,766
16219.7.128.0/17219.7.128.1 to 219.7.255.254219.7.255.25532,766
17219.8.0.0/17219.8.0.1 to 219.8.127.254219.8.127.25532,766
18219.8.128.0/17219.8.128.1 to 219.8.255.254219.8.255.25532,766
19219.9.0.0/17219.9.0.1 to 219.9.127.254219.9.127.25532,766
20219.9.128.0/17219.9.128.1 to 219.9.255.254219.9.255.25532,766
21219.10.0.0/17219.10.0.1 to 219.10.127.254219.10.127.25532,766
22219.10.128.0/17219.10.128.1 to 219.10.255.254219.10.255.25532,766
23219.11.0.0/17219.11.0.1 to 219.11.127.254219.11.127.25532,766
24219.11.128.0/17219.11.128.1 to 219.11.255.254219.11.255.25532,766
25219.12.0.0/17219.12.0.1 to 219.12.127.254219.12.127.25532,766
26219.12.128.0/17219.12.128.1 to 219.12.255.254219.12.255.25532,766
27219.13.0.0/17219.13.0.1 to 219.13.127.254219.13.127.25532,766
28219.13.128.0/17219.13.128.1 to 219.13.255.254219.13.255.25532,766
29219.14.0.0/17219.14.0.1 to 219.14.127.254219.14.127.25532,766
30219.14.128.0/17219.14.128.1 to 219.14.255.254219.14.255.25532,766
31219.15.0.0/17219.15.0.1 to 219.15.127.254219.15.127.25532,766
32219.15.128.0/17219.15.128.1 to 219.15.255.254219.15.255.25532,766
33219.16.0.0/17219.16.0.1 to 219.16.127.254219.16.127.25532,766
34219.16.128.0/17219.16.128.1 to 219.16.255.254219.16.255.25532,766
35219.17.0.0/17219.17.0.1 to 219.17.127.254219.17.127.25532,766
36219.17.128.0/17219.17.128.1 to 219.17.255.254219.17.255.25532,766
37219.18.0.0/17219.18.0.1 to 219.18.127.254219.18.127.25532,766
38219.18.128.0/17219.18.128.1 to 219.18.255.254219.18.255.25532,766
39219.19.0.0/17219.19.0.1 to 219.19.127.254219.19.127.25532,766
40219.19.128.0/17219.19.128.1 to 219.19.255.254219.19.255.25532,766
41219.20.0.0/17219.20.0.1 to 219.20.127.254219.20.127.25532,766
42219.20.128.0/17219.20.128.1 to 219.20.255.254219.20.255.25532,766
43219.21.0.0/17219.21.0.1 to 219.21.127.254219.21.127.25532,766
44219.21.128.0/17219.21.128.1 to 219.21.255.254219.21.255.25532,766
45219.22.0.0/17219.22.0.1 to 219.22.127.254219.22.127.25532,766
46219.22.128.0/17219.22.128.1 to 219.22.255.254219.22.255.25532,766
47219.23.0.0/17219.23.0.1 to 219.23.127.254219.23.127.25532,766
48219.23.128.0/17219.23.128.1 to 219.23.255.254219.23.255.25532,766
49219.24.0.0/17219.24.0.1 to 219.24.127.254219.24.127.25532,766
50219.24.128.0/17219.24.128.1 to 219.24.255.254219.24.255.25532,766
51219.25.0.0/17219.25.0.1 to 219.25.127.254219.25.127.25532,766
52219.25.128.0/17219.25.128.1 to 219.25.255.254219.25.255.25532,766
53219.26.0.0/17219.26.0.1 to 219.26.127.254219.26.127.25532,766
54219.26.128.0/17219.26.128.1 to 219.26.255.254219.26.255.25532,766
55219.27.0.0/17219.27.0.1 to 219.27.127.254219.27.127.25532,766
56219.27.128.0/17219.27.128.1 to 219.27.255.254219.27.255.25532,766
57219.28.0.0/17219.28.0.1 to 219.28.127.254219.28.127.25532,766
58219.28.128.0/17219.28.128.1 to 219.28.255.254219.28.255.25532,766
59219.29.0.0/17219.29.0.1 to 219.29.127.254219.29.127.25532,766
60219.29.128.0/17219.29.128.1 to 219.29.255.254219.29.255.25532,766
61219.30.0.0/17219.30.0.1 to 219.30.127.254219.30.127.25532,766
62219.30.128.0/17219.30.128.1 to 219.30.255.254219.30.255.25532,766
63219.31.0.0/17219.31.0.1 to 219.31.127.254219.31.127.25532,766
64219.31.128.0/17219.31.128.1 to 219.31.255.254219.31.255.25532,766
65219.32.0.0/17219.32.0.1 to 219.32.127.254219.32.127.25532,766
66219.32.128.0/17219.32.128.1 to 219.32.255.254219.32.255.25532,766
67219.33.0.0/17219.33.0.1 to 219.33.127.254219.33.127.25532,766
68219.33.128.0/17219.33.128.1 to 219.33.255.254219.33.255.25532,766
69219.34.0.0/17219.34.0.1 to 219.34.127.254219.34.127.25532,766
70219.34.128.0/17219.34.128.1 to 219.34.255.254219.34.255.25532,766
71219.35.0.0/17219.35.0.1 to 219.35.127.254219.35.127.25532,766
72219.35.128.0/17219.35.128.1 to 219.35.255.254219.35.255.25532,766
73219.36.0.0/17219.36.0.1 to 219.36.127.254219.36.127.25532,766
74219.36.128.0/17219.36.128.1 to 219.36.255.254219.36.255.25532,766
75219.37.0.0/17219.37.0.1 to 219.37.127.254219.37.127.25532,766
76219.37.128.0/17219.37.128.1 to 219.37.255.254219.37.255.25532,766
77219.38.0.0/17219.38.0.1 to 219.38.127.254219.38.127.25532,766
78219.38.128.0/17219.38.128.1 to 219.38.255.254219.38.255.25532,766
79219.39.0.0/17219.39.0.1 to 219.39.127.254219.39.127.25532,766
80219.39.128.0/17219.39.128.1 to 219.39.255.254219.39.255.25532,766
81219.40.0.0/17219.40.0.1 to 219.40.127.254219.40.127.25532,766
82219.40.128.0/17219.40.128.1 to 219.40.255.254219.40.255.25532,766
83219.41.0.0/17219.41.0.1 to 219.41.127.254219.41.127.25532,766
84219.41.128.0/17219.41.128.1 to 219.41.255.254219.41.255.25532,766
85219.42.0.0/17219.42.0.1 to 219.42.127.254219.42.127.25532,766
86219.42.128.0/17219.42.128.1 to 219.42.255.254219.42.255.25532,766
87219.43.0.0/17219.43.0.1 to 219.43.127.254219.43.127.25532,766
88219.43.128.0/17219.43.128.1 to 219.43.255.254219.43.255.25532,766
89219.44.0.0/17219.44.0.1 to 219.44.127.254219.44.127.25532,766
90219.44.128.0/17219.44.128.1 to 219.44.255.254219.44.255.25532,766
91219.45.0.0/17219.45.0.1 to 219.45.127.254219.45.127.25532,766
92219.45.128.0/17219.45.128.1 to 219.45.255.254219.45.255.25532,766
93219.46.0.0/17219.46.0.1 to 219.46.127.254219.46.127.25532,766
94219.46.128.0/17219.46.128.1 to 219.46.255.254219.46.255.25532,766
95219.47.0.0/17219.47.0.1 to 219.47.127.254219.47.127.25532,766
96219.47.128.0/17219.47.128.1 to 219.47.255.254219.47.255.25532,766
97219.48.0.0/17219.48.0.1 to 219.48.127.254219.48.127.25532,766
98219.48.128.0/17219.48.128.1 to 219.48.255.254219.48.255.25532,766
99219.49.0.0/17219.49.0.1 to 219.49.127.254219.49.127.25532,766
100219.49.128.0/17219.49.128.1 to 219.49.255.254219.49.255.25532,766
101219.50.0.0/17219.50.0.1 to 219.50.127.254219.50.127.25532,766
102219.50.128.0/17219.50.128.1 to 219.50.255.254219.50.255.25532,766
103219.51.0.0/17219.51.0.1 to 219.51.127.254219.51.127.25532,766
104219.51.128.0/17219.51.128.1 to 219.51.255.254219.51.255.25532,766
105219.52.0.0/17219.52.0.1 to 219.52.127.254219.52.127.25532,766
106219.52.128.0/17219.52.128.1 to 219.52.255.254219.52.255.25532,766
107219.53.0.0/17219.53.0.1 to 219.53.127.254219.53.127.25532,766
108219.53.128.0/17219.53.128.1 to 219.53.255.254219.53.255.25532,766
109219.54.0.0/17219.54.0.1 to 219.54.127.254219.54.127.25532,766
110219.54.128.0/17219.54.128.1 to 219.54.255.254219.54.255.25532,766
111219.55.0.0/17219.55.0.1 to 219.55.127.254219.55.127.25532,766
112219.55.128.0/17219.55.128.1 to 219.55.255.254219.55.255.25532,766
113219.56.0.0/17219.56.0.1 to 219.56.127.254219.56.127.25532,766
114219.56.128.0/17219.56.128.1 to 219.56.255.254219.56.255.25532,766
115219.57.0.0/17219.57.0.1 to 219.57.127.254219.57.127.25532,766
116219.57.128.0/17219.57.128.1 to 219.57.255.254219.57.255.25532,766
117219.58.0.0/17219.58.0.1 to 219.58.127.254219.58.127.25532,766
118219.58.128.0/17219.58.128.1 to 219.58.255.254219.58.255.25532,766
119219.59.0.0/17219.59.0.1 to 219.59.127.254219.59.127.25532,766
120219.59.128.0/17219.59.128.1 to 219.59.255.254219.59.255.25532,766
121219.60.0.0/17219.60.0.1 to 219.60.127.254219.60.127.25532,766
122219.60.128.0/17219.60.128.1 to 219.60.255.254219.60.255.25532,766
123219.61.0.0/17219.61.0.1 to 219.61.127.254219.61.127.25532,766
124219.61.128.0/17219.61.128.1 to 219.61.255.254219.61.255.25532,766
125219.62.0.0/17219.62.0.1 to 219.62.127.254219.62.127.25532,766
126219.62.128.0/17219.62.128.1 to 219.62.255.254219.62.255.25532,766
127219.63.0.0/17219.63.0.1 to 219.63.127.254219.63.127.25532,766
128219.63.128.0/17219.63.128.1 to 219.63.255.254219.63.255.25532,766
129219.64.0.0/17219.64.0.1 to 219.64.127.254219.64.127.25532,766
130219.64.128.0/17219.64.128.1 to 219.64.255.254219.64.255.25532,766
131219.65.0.0/17219.65.0.1 to 219.65.127.254219.65.127.25532,766
132219.65.128.0/17219.65.128.1 to 219.65.255.254219.65.255.25532,766
133219.66.0.0/17219.66.0.1 to 219.66.127.254219.66.127.25532,766
134219.66.128.0/17219.66.128.1 to 219.66.255.254219.66.255.25532,766
135219.67.0.0/17219.67.0.1 to 219.67.127.254219.67.127.25532,766
136219.67.128.0/17219.67.128.1 to 219.67.255.254219.67.255.25532,766
137219.68.0.0/17219.68.0.1 to 219.68.127.254219.68.127.25532,766
138219.68.128.0/17219.68.128.1 to 219.68.255.254219.68.255.25532,766
139219.69.0.0/17219.69.0.1 to 219.69.127.254219.69.127.25532,766
140219.69.128.0/17219.69.128.1 to 219.69.255.254219.69.255.25532,766
141219.70.0.0/17219.70.0.1 to 219.70.127.254219.70.127.25532,766
142219.70.128.0/17219.70.128.1 to 219.70.255.254219.70.255.25532,766
143219.71.0.0/17219.71.0.1 to 219.71.127.254219.71.127.25532,766
144219.71.128.0/17219.71.128.1 to 219.71.255.254219.71.255.25532,766
145219.72.0.0/17219.72.0.1 to 219.72.127.254219.72.127.25532,766
146219.72.128.0/17219.72.128.1 to 219.72.255.254219.72.255.25532,766
147219.73.0.0/17219.73.0.1 to 219.73.127.254219.73.127.25532,766
148219.73.128.0/17219.73.128.1 to 219.73.255.254219.73.255.25532,766
149219.74.0.0/17219.74.0.1 to 219.74.127.254219.74.127.25532,766
150219.74.128.0/17219.74.128.1 to 219.74.255.254219.74.255.25532,766
151219.75.0.0/17219.75.0.1 to 219.75.127.254219.75.127.25532,766
152219.75.128.0/17219.75.128.1 to 219.75.255.254219.75.255.25532,766
153219.76.0.0/17219.76.0.1 to 219.76.127.254219.76.127.25532,766
154219.76.128.0/17219.76.128.1 to 219.76.255.254219.76.255.25532,766
155219.77.0.0/17219.77.0.1 to 219.77.127.254219.77.127.25532,766
156219.77.128.0/17219.77.128.1 to 219.77.255.254219.77.255.25532,766
157219.78.0.0/17219.78.0.1 to 219.78.127.254219.78.127.25532,766
158219.78.128.0/17219.78.128.1 to 219.78.255.254219.78.255.25532,766
159219.79.0.0/17219.79.0.1 to 219.79.127.254219.79.127.25532,766
160219.79.128.0/17219.79.128.1 to 219.79.255.254219.79.255.25532,766
161219.80.0.0/17219.80.0.1 to 219.80.127.254219.80.127.25532,766
162219.80.128.0/17219.80.128.1 to 219.80.255.254219.80.255.25532,766
163219.81.0.0/17219.81.0.1 to 219.81.127.254219.81.127.25532,766
164219.81.128.0/17219.81.128.1 to 219.81.255.254219.81.255.25532,766
165219.82.0.0/17219.82.0.1 to 219.82.127.254219.82.127.25532,766
166219.82.128.0/17219.82.128.1 to 219.82.255.254219.82.255.25532,766
167219.83.0.0/17219.83.0.1 to 219.83.127.254219.83.127.25532,766
168219.83.128.0/17219.83.128.1 to 219.83.255.254219.83.255.25532,766
169219.84.0.0/17219.84.0.1 to 219.84.127.254219.84.127.25532,766
170219.84.128.0/17219.84.128.1 to 219.84.255.254219.84.255.25532,766
171219.85.0.0/17219.85.0.1 to 219.85.127.254219.85.127.25532,766
172219.85.128.0/17219.85.128.1 to 219.85.255.254219.85.255.25532,766
173219.86.0.0/17219.86.0.1 to 219.86.127.254219.86.127.25532,766
174219.86.128.0/17219.86.128.1 to 219.86.255.254219.86.255.25532,766
175219.87.0.0/17219.87.0.1 to 219.87.127.254219.87.127.25532,766
176219.87.128.0/17219.87.128.1 to 219.87.255.254219.87.255.25532,766
177219.88.0.0/17219.88.0.1 to 219.88.127.254219.88.127.25532,766
178219.88.128.0/17219.88.128.1 to 219.88.255.254219.88.255.25532,766
179219.89.0.0/17219.89.0.1 to 219.89.127.254219.89.127.25532,766
180219.89.128.0/17219.89.128.1 to 219.89.255.254219.89.255.25532,766
181219.90.0.0/17219.90.0.1 to 219.90.127.254219.90.127.25532,766
182219.90.128.0/17219.90.128.1 to 219.90.255.254219.90.255.25532,766
183219.91.0.0/17219.91.0.1 to 219.91.127.254219.91.127.25532,766
184219.91.128.0/17219.91.128.1 to 219.91.255.254219.91.255.25532,766
185219.92.0.0/17219.92.0.1 to 219.92.127.254219.92.127.25532,766
186219.92.128.0/17219.92.128.1 to 219.92.255.254219.92.255.25532,766
187219.93.0.0/17219.93.0.1 to 219.93.127.254219.93.127.25532,766
188219.93.128.0/17219.93.128.1 to 219.93.255.254219.93.255.25532,766
189219.94.0.0/17219.94.0.1 to 219.94.127.254219.94.127.25532,766
190219.94.128.0/17219.94.128.1 to 219.94.255.254219.94.255.25532,766
191219.95.0.0/17219.95.0.1 to 219.95.127.254219.95.127.25532,766
192219.95.128.0/17219.95.128.1 to 219.95.255.254219.95.255.25532,766
193219.96.0.0/17219.96.0.1 to 219.96.127.254219.96.127.25532,766
194219.96.128.0/17219.96.128.1 to 219.96.255.254219.96.255.25532,766
195219.97.0.0/17219.97.0.1 to 219.97.127.254219.97.127.25532,766
196219.97.128.0/17219.97.128.1 to 219.97.255.254219.97.255.25532,766
197219.98.0.0/17219.98.0.1 to 219.98.127.254219.98.127.25532,766
198219.98.128.0/17219.98.128.1 to 219.98.255.254219.98.255.25532,766
199219.99.0.0/17219.99.0.1 to 219.99.127.254219.99.127.25532,766
200219.99.128.0/17219.99.128.1 to 219.99.255.254219.99.255.25532,766
201219.100.0.0/17219.100.0.1 to 219.100.127.254219.100.127.25532,766
202219.100.128.0/17219.100.128.1 to 219.100.255.254219.100.255.25532,766
203219.101.0.0/17219.101.0.1 to 219.101.127.254219.101.127.25532,766
204219.101.128.0/17219.101.128.1 to 219.101.255.254219.101.255.25532,766
205219.102.0.0/17219.102.0.1 to 219.102.127.254219.102.127.25532,766
206219.102.128.0/17219.102.128.1 to 219.102.255.254219.102.255.25532,766
207219.103.0.0/17219.103.0.1 to 219.103.127.254219.103.127.25532,766
208219.103.128.0/17219.103.128.1 to 219.103.255.254219.103.255.25532,766
209219.104.0.0/17219.104.0.1 to 219.104.127.254219.104.127.25532,766
210219.104.128.0/17219.104.128.1 to 219.104.255.254219.104.255.25532,766
211219.105.0.0/17219.105.0.1 to 219.105.127.254219.105.127.25532,766
212219.105.128.0/17219.105.128.1 to 219.105.255.254219.105.255.25532,766
213219.106.0.0/17219.106.0.1 to 219.106.127.254219.106.127.25532,766
214219.106.128.0/17219.106.128.1 to 219.106.255.254219.106.255.25532,766
215219.107.0.0/17219.107.0.1 to 219.107.127.254219.107.127.25532,766
216219.107.128.0/17219.107.128.1 to 219.107.255.254219.107.255.25532,766
217219.108.0.0/17219.108.0.1 to 219.108.127.254219.108.127.25532,766
218219.108.128.0/17219.108.128.1 to 219.108.255.254219.108.255.25532,766
219219.109.0.0/17219.109.0.1 to 219.109.127.254219.109.127.25532,766
220219.109.128.0/17219.109.128.1 to 219.109.255.254219.109.255.25532,766
221219.110.0.0/17219.110.0.1 to 219.110.127.254219.110.127.25532,766
222219.110.128.0/17219.110.128.1 to 219.110.255.254219.110.255.25532,766
223219.111.0.0/17219.111.0.1 to 219.111.127.254219.111.127.25532,766
224219.111.128.0/17219.111.128.1 to 219.111.255.254219.111.255.25532,766
225219.112.0.0/17219.112.0.1 to 219.112.127.254219.112.127.25532,766
226219.112.128.0/17219.112.128.1 to 219.112.255.254219.112.255.25532,766
227219.113.0.0/17219.113.0.1 to 219.113.127.254219.113.127.25532,766
228219.113.128.0/17219.113.128.1 to 219.113.255.254219.113.255.25532,766
229219.114.0.0/17219.114.0.1 to 219.114.127.254219.114.127.25532,766
230219.114.128.0/17219.114.128.1 to 219.114.255.254219.114.255.25532,766
231219.115.0.0/17219.115.0.1 to 219.115.127.254219.115.127.25532,766
232219.115.128.0/17219.115.128.1 to 219.115.255.254219.115.255.25532,766
233219.116.0.0/17219.116.0.1 to 219.116.127.254219.116.127.25532,766
234219.116.128.0/17219.116.128.1 to 219.116.255.254219.116.255.25532,766
235219.117.0.0/17219.117.0.1 to 219.117.127.254219.117.127.25532,766
236219.117.128.0/17219.117.128.1 to 219.117.255.254219.117.255.25532,766
237219.118.0.0/17219.118.0.1 to 219.118.127.254219.118.127.25532,766
238219.118.128.0/17219.118.128.1 to 219.118.255.254219.118.255.25532,766
239219.119.0.0/17219.119.0.1 to 219.119.127.254219.119.127.25532,766
240219.119.128.0/17219.119.128.1 to 219.119.255.254219.119.255.25532,766
241219.120.0.0/17219.120.0.1 to 219.120.127.254219.120.127.25532,766
242219.120.128.0/17219.120.128.1 to 219.120.255.254219.120.255.25532,766
243219.121.0.0/17219.121.0.1 to 219.121.127.254219.121.127.25532,766
244219.121.128.0/17219.121.128.1 to 219.121.255.254219.121.255.25532,766
245219.122.0.0/17219.122.0.1 to 219.122.127.254219.122.127.25532,766
246219.122.128.0/17219.122.128.1 to 219.122.255.254219.122.255.25532,766
247219.123.0.0/17219.123.0.1 to 219.123.127.254219.123.127.25532,766
248219.123.128.0/17219.123.128.1 to 219.123.255.254219.123.255.25532,766
249219.124.0.0/17219.124.0.1 to 219.124.127.254219.124.127.25532,766
250219.124.128.0/17219.124.128.1 to 219.124.255.254219.124.255.25532,766
251219.125.0.0/17219.125.0.1 to 219.125.127.254219.125.127.25532,766
252219.125.128.0/17219.125.128.1 to 219.125.255.254219.125.255.25532,766
253219.126.0.0/17219.126.0.1 to 219.126.127.254219.126.127.25532,766
254219.126.128.0/17219.126.128.1 to 219.126.255.254219.126.255.25532,766
255219.127.0.0/17219.127.0.1 to 219.127.127.254219.127.127.25532,766
256219.127.128.0/17219.127.128.1 to 219.127.255.254219.127.255.25532,766

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.