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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.

Network217.78.0.0/16
Usable hosts65,534
Subnet mask255.255.0.0
Addresses65,536
Network address
217.78.0.0
Broadcast address
217.78.255.255
First usable
217.78.0.1
Last usable
217.78.255.254
Usable hosts
65,534 (65,536 less the network and broadcast addresses)
Subnet mask
255.255.0.0
Wildcard mask
0.0.255.255 (Cisco ACLs, OSPF)
Prefix length
/16
Type
Public public
Old class
C (default /24)
As numbers
Hex D94E0000 · Integer 3645767680 to 3645833215
Reverse DNS zone
78.217.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11011001.01001110..00000000.00000000217.78.0.0
Subnet mask11111111.11111111..00000000.00000000255.255.0.0
Network11011001.01001110..00000000.00000000217.78.0.0
Broadcast11011001.01001110..11111111.11111111217.78.255.255
Split into smaller subnets/25
/17 (2)/18 (4)/19 (8)/20 (16)/21 (32)/22 (64)/23 (128)/24 (256)/25 (512)/26 (1,024)/27 (2,048)/28 (4,096)

217.78.0.0/16 makes 512 subnets of /25; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1217.78.0.0/25217.78.0.1 to 217.78.0.126217.78.0.127126
2217.78.0.128/25217.78.0.129 to 217.78.0.254217.78.0.255126
3217.78.1.0/25217.78.1.1 to 217.78.1.126217.78.1.127126
4217.78.1.128/25217.78.1.129 to 217.78.1.254217.78.1.255126
5217.78.2.0/25217.78.2.1 to 217.78.2.126217.78.2.127126
6217.78.2.128/25217.78.2.129 to 217.78.2.254217.78.2.255126
7217.78.3.0/25217.78.3.1 to 217.78.3.126217.78.3.127126
8217.78.3.128/25217.78.3.129 to 217.78.3.254217.78.3.255126
9217.78.4.0/25217.78.4.1 to 217.78.4.126217.78.4.127126
10217.78.4.128/25217.78.4.129 to 217.78.4.254217.78.4.255126
11217.78.5.0/25217.78.5.1 to 217.78.5.126217.78.5.127126
12217.78.5.128/25217.78.5.129 to 217.78.5.254217.78.5.255126
13217.78.6.0/25217.78.6.1 to 217.78.6.126217.78.6.127126
14217.78.6.128/25217.78.6.129 to 217.78.6.254217.78.6.255126
15217.78.7.0/25217.78.7.1 to 217.78.7.126217.78.7.127126
16217.78.7.128/25217.78.7.129 to 217.78.7.254217.78.7.255126
17217.78.8.0/25217.78.8.1 to 217.78.8.126217.78.8.127126
18217.78.8.128/25217.78.8.129 to 217.78.8.254217.78.8.255126
19217.78.9.0/25217.78.9.1 to 217.78.9.126217.78.9.127126
20217.78.9.128/25217.78.9.129 to 217.78.9.254217.78.9.255126
21217.78.10.0/25217.78.10.1 to 217.78.10.126217.78.10.127126
22217.78.10.128/25217.78.10.129 to 217.78.10.254217.78.10.255126
23217.78.11.0/25217.78.11.1 to 217.78.11.126217.78.11.127126
24217.78.11.128/25217.78.11.129 to 217.78.11.254217.78.11.255126
25217.78.12.0/25217.78.12.1 to 217.78.12.126217.78.12.127126
26217.78.12.128/25217.78.12.129 to 217.78.12.254217.78.12.255126
27217.78.13.0/25217.78.13.1 to 217.78.13.126217.78.13.127126
28217.78.13.128/25217.78.13.129 to 217.78.13.254217.78.13.255126
29217.78.14.0/25217.78.14.1 to 217.78.14.126217.78.14.127126
30217.78.14.128/25217.78.14.129 to 217.78.14.254217.78.14.255126
31217.78.15.0/25217.78.15.1 to 217.78.15.126217.78.15.127126
32217.78.15.128/25217.78.15.129 to 217.78.15.254217.78.15.255126
33217.78.16.0/25217.78.16.1 to 217.78.16.126217.78.16.127126
34217.78.16.128/25217.78.16.129 to 217.78.16.254217.78.16.255126
35217.78.17.0/25217.78.17.1 to 217.78.17.126217.78.17.127126
36217.78.17.128/25217.78.17.129 to 217.78.17.254217.78.17.255126
37217.78.18.0/25217.78.18.1 to 217.78.18.126217.78.18.127126
38217.78.18.128/25217.78.18.129 to 217.78.18.254217.78.18.255126
39217.78.19.0/25217.78.19.1 to 217.78.19.126217.78.19.127126
40217.78.19.128/25217.78.19.129 to 217.78.19.254217.78.19.255126
41217.78.20.0/25217.78.20.1 to 217.78.20.126217.78.20.127126
42217.78.20.128/25217.78.20.129 to 217.78.20.254217.78.20.255126
43217.78.21.0/25217.78.21.1 to 217.78.21.126217.78.21.127126
44217.78.21.128/25217.78.21.129 to 217.78.21.254217.78.21.255126
45217.78.22.0/25217.78.22.1 to 217.78.22.126217.78.22.127126
46217.78.22.128/25217.78.22.129 to 217.78.22.254217.78.22.255126
47217.78.23.0/25217.78.23.1 to 217.78.23.126217.78.23.127126
48217.78.23.128/25217.78.23.129 to 217.78.23.254217.78.23.255126
49217.78.24.0/25217.78.24.1 to 217.78.24.126217.78.24.127126
50217.78.24.128/25217.78.24.129 to 217.78.24.254217.78.24.255126
51217.78.25.0/25217.78.25.1 to 217.78.25.126217.78.25.127126
52217.78.25.128/25217.78.25.129 to 217.78.25.254217.78.25.255126
53217.78.26.0/25217.78.26.1 to 217.78.26.126217.78.26.127126
54217.78.26.128/25217.78.26.129 to 217.78.26.254217.78.26.255126
55217.78.27.0/25217.78.27.1 to 217.78.27.126217.78.27.127126
56217.78.27.128/25217.78.27.129 to 217.78.27.254217.78.27.255126
57217.78.28.0/25217.78.28.1 to 217.78.28.126217.78.28.127126
58217.78.28.128/25217.78.28.129 to 217.78.28.254217.78.28.255126
59217.78.29.0/25217.78.29.1 to 217.78.29.126217.78.29.127126
60217.78.29.128/25217.78.29.129 to 217.78.29.254217.78.29.255126
61217.78.30.0/25217.78.30.1 to 217.78.30.126217.78.30.127126
62217.78.30.128/25217.78.30.129 to 217.78.30.254217.78.30.255126
63217.78.31.0/25217.78.31.1 to 217.78.31.126217.78.31.127126
64217.78.31.128/25217.78.31.129 to 217.78.31.254217.78.31.255126
65217.78.32.0/25217.78.32.1 to 217.78.32.126217.78.32.127126
66217.78.32.128/25217.78.32.129 to 217.78.32.254217.78.32.255126
67217.78.33.0/25217.78.33.1 to 217.78.33.126217.78.33.127126
68217.78.33.128/25217.78.33.129 to 217.78.33.254217.78.33.255126
69217.78.34.0/25217.78.34.1 to 217.78.34.126217.78.34.127126
70217.78.34.128/25217.78.34.129 to 217.78.34.254217.78.34.255126
71217.78.35.0/25217.78.35.1 to 217.78.35.126217.78.35.127126
72217.78.35.128/25217.78.35.129 to 217.78.35.254217.78.35.255126
73217.78.36.0/25217.78.36.1 to 217.78.36.126217.78.36.127126
74217.78.36.128/25217.78.36.129 to 217.78.36.254217.78.36.255126
75217.78.37.0/25217.78.37.1 to 217.78.37.126217.78.37.127126
76217.78.37.128/25217.78.37.129 to 217.78.37.254217.78.37.255126
77217.78.38.0/25217.78.38.1 to 217.78.38.126217.78.38.127126
78217.78.38.128/25217.78.38.129 to 217.78.38.254217.78.38.255126
79217.78.39.0/25217.78.39.1 to 217.78.39.126217.78.39.127126
80217.78.39.128/25217.78.39.129 to 217.78.39.254217.78.39.255126
81217.78.40.0/25217.78.40.1 to 217.78.40.126217.78.40.127126
82217.78.40.128/25217.78.40.129 to 217.78.40.254217.78.40.255126
83217.78.41.0/25217.78.41.1 to 217.78.41.126217.78.41.127126
84217.78.41.128/25217.78.41.129 to 217.78.41.254217.78.41.255126
85217.78.42.0/25217.78.42.1 to 217.78.42.126217.78.42.127126
86217.78.42.128/25217.78.42.129 to 217.78.42.254217.78.42.255126
87217.78.43.0/25217.78.43.1 to 217.78.43.126217.78.43.127126
88217.78.43.128/25217.78.43.129 to 217.78.43.254217.78.43.255126
89217.78.44.0/25217.78.44.1 to 217.78.44.126217.78.44.127126
90217.78.44.128/25217.78.44.129 to 217.78.44.254217.78.44.255126
91217.78.45.0/25217.78.45.1 to 217.78.45.126217.78.45.127126
92217.78.45.128/25217.78.45.129 to 217.78.45.254217.78.45.255126
93217.78.46.0/25217.78.46.1 to 217.78.46.126217.78.46.127126
94217.78.46.128/25217.78.46.129 to 217.78.46.254217.78.46.255126
95217.78.47.0/25217.78.47.1 to 217.78.47.126217.78.47.127126
96217.78.47.128/25217.78.47.129 to 217.78.47.254217.78.47.255126
97217.78.48.0/25217.78.48.1 to 217.78.48.126217.78.48.127126
98217.78.48.128/25217.78.48.129 to 217.78.48.254217.78.48.255126
99217.78.49.0/25217.78.49.1 to 217.78.49.126217.78.49.127126
100217.78.49.128/25217.78.49.129 to 217.78.49.254217.78.49.255126
101217.78.50.0/25217.78.50.1 to 217.78.50.126217.78.50.127126
102217.78.50.128/25217.78.50.129 to 217.78.50.254217.78.50.255126
103217.78.51.0/25217.78.51.1 to 217.78.51.126217.78.51.127126
104217.78.51.128/25217.78.51.129 to 217.78.51.254217.78.51.255126
105217.78.52.0/25217.78.52.1 to 217.78.52.126217.78.52.127126
106217.78.52.128/25217.78.52.129 to 217.78.52.254217.78.52.255126
107217.78.53.0/25217.78.53.1 to 217.78.53.126217.78.53.127126
108217.78.53.128/25217.78.53.129 to 217.78.53.254217.78.53.255126
109217.78.54.0/25217.78.54.1 to 217.78.54.126217.78.54.127126
110217.78.54.128/25217.78.54.129 to 217.78.54.254217.78.54.255126
111217.78.55.0/25217.78.55.1 to 217.78.55.126217.78.55.127126
112217.78.55.128/25217.78.55.129 to 217.78.55.254217.78.55.255126
113217.78.56.0/25217.78.56.1 to 217.78.56.126217.78.56.127126
114217.78.56.128/25217.78.56.129 to 217.78.56.254217.78.56.255126
115217.78.57.0/25217.78.57.1 to 217.78.57.126217.78.57.127126
116217.78.57.128/25217.78.57.129 to 217.78.57.254217.78.57.255126
117217.78.58.0/25217.78.58.1 to 217.78.58.126217.78.58.127126
118217.78.58.128/25217.78.58.129 to 217.78.58.254217.78.58.255126
119217.78.59.0/25217.78.59.1 to 217.78.59.126217.78.59.127126
120217.78.59.128/25217.78.59.129 to 217.78.59.254217.78.59.255126
121217.78.60.0/25217.78.60.1 to 217.78.60.126217.78.60.127126
122217.78.60.128/25217.78.60.129 to 217.78.60.254217.78.60.255126
123217.78.61.0/25217.78.61.1 to 217.78.61.126217.78.61.127126
124217.78.61.128/25217.78.61.129 to 217.78.61.254217.78.61.255126
125217.78.62.0/25217.78.62.1 to 217.78.62.126217.78.62.127126
126217.78.62.128/25217.78.62.129 to 217.78.62.254217.78.62.255126
127217.78.63.0/25217.78.63.1 to 217.78.63.126217.78.63.127126
128217.78.63.128/25217.78.63.129 to 217.78.63.254217.78.63.255126
129217.78.64.0/25217.78.64.1 to 217.78.64.126217.78.64.127126
130217.78.64.128/25217.78.64.129 to 217.78.64.254217.78.64.255126
131217.78.65.0/25217.78.65.1 to 217.78.65.126217.78.65.127126
132217.78.65.128/25217.78.65.129 to 217.78.65.254217.78.65.255126
133217.78.66.0/25217.78.66.1 to 217.78.66.126217.78.66.127126
134217.78.66.128/25217.78.66.129 to 217.78.66.254217.78.66.255126
135217.78.67.0/25217.78.67.1 to 217.78.67.126217.78.67.127126
136217.78.67.128/25217.78.67.129 to 217.78.67.254217.78.67.255126
137217.78.68.0/25217.78.68.1 to 217.78.68.126217.78.68.127126
138217.78.68.128/25217.78.68.129 to 217.78.68.254217.78.68.255126
139217.78.69.0/25217.78.69.1 to 217.78.69.126217.78.69.127126
140217.78.69.128/25217.78.69.129 to 217.78.69.254217.78.69.255126
141217.78.70.0/25217.78.70.1 to 217.78.70.126217.78.70.127126
142217.78.70.128/25217.78.70.129 to 217.78.70.254217.78.70.255126
143217.78.71.0/25217.78.71.1 to 217.78.71.126217.78.71.127126
144217.78.71.128/25217.78.71.129 to 217.78.71.254217.78.71.255126
145217.78.72.0/25217.78.72.1 to 217.78.72.126217.78.72.127126
146217.78.72.128/25217.78.72.129 to 217.78.72.254217.78.72.255126
147217.78.73.0/25217.78.73.1 to 217.78.73.126217.78.73.127126
148217.78.73.128/25217.78.73.129 to 217.78.73.254217.78.73.255126
149217.78.74.0/25217.78.74.1 to 217.78.74.126217.78.74.127126
150217.78.74.128/25217.78.74.129 to 217.78.74.254217.78.74.255126
151217.78.75.0/25217.78.75.1 to 217.78.75.126217.78.75.127126
152217.78.75.128/25217.78.75.129 to 217.78.75.254217.78.75.255126
153217.78.76.0/25217.78.76.1 to 217.78.76.126217.78.76.127126
154217.78.76.128/25217.78.76.129 to 217.78.76.254217.78.76.255126
155217.78.77.0/25217.78.77.1 to 217.78.77.126217.78.77.127126
156217.78.77.128/25217.78.77.129 to 217.78.77.254217.78.77.255126
157217.78.78.0/25217.78.78.1 to 217.78.78.126217.78.78.127126
158217.78.78.128/25217.78.78.129 to 217.78.78.254217.78.78.255126
159217.78.79.0/25217.78.79.1 to 217.78.79.126217.78.79.127126
160217.78.79.128/25217.78.79.129 to 217.78.79.254217.78.79.255126
161217.78.80.0/25217.78.80.1 to 217.78.80.126217.78.80.127126
162217.78.80.128/25217.78.80.129 to 217.78.80.254217.78.80.255126
163217.78.81.0/25217.78.81.1 to 217.78.81.126217.78.81.127126
164217.78.81.128/25217.78.81.129 to 217.78.81.254217.78.81.255126
165217.78.82.0/25217.78.82.1 to 217.78.82.126217.78.82.127126
166217.78.82.128/25217.78.82.129 to 217.78.82.254217.78.82.255126
167217.78.83.0/25217.78.83.1 to 217.78.83.126217.78.83.127126
168217.78.83.128/25217.78.83.129 to 217.78.83.254217.78.83.255126
169217.78.84.0/25217.78.84.1 to 217.78.84.126217.78.84.127126
170217.78.84.128/25217.78.84.129 to 217.78.84.254217.78.84.255126
171217.78.85.0/25217.78.85.1 to 217.78.85.126217.78.85.127126
172217.78.85.128/25217.78.85.129 to 217.78.85.254217.78.85.255126
173217.78.86.0/25217.78.86.1 to 217.78.86.126217.78.86.127126
174217.78.86.128/25217.78.86.129 to 217.78.86.254217.78.86.255126
175217.78.87.0/25217.78.87.1 to 217.78.87.126217.78.87.127126
176217.78.87.128/25217.78.87.129 to 217.78.87.254217.78.87.255126
177217.78.88.0/25217.78.88.1 to 217.78.88.126217.78.88.127126
178217.78.88.128/25217.78.88.129 to 217.78.88.254217.78.88.255126
179217.78.89.0/25217.78.89.1 to 217.78.89.126217.78.89.127126
180217.78.89.128/25217.78.89.129 to 217.78.89.254217.78.89.255126
181217.78.90.0/25217.78.90.1 to 217.78.90.126217.78.90.127126
182217.78.90.128/25217.78.90.129 to 217.78.90.254217.78.90.255126
183217.78.91.0/25217.78.91.1 to 217.78.91.126217.78.91.127126
184217.78.91.128/25217.78.91.129 to 217.78.91.254217.78.91.255126
185217.78.92.0/25217.78.92.1 to 217.78.92.126217.78.92.127126
186217.78.92.128/25217.78.92.129 to 217.78.92.254217.78.92.255126
187217.78.93.0/25217.78.93.1 to 217.78.93.126217.78.93.127126
188217.78.93.128/25217.78.93.129 to 217.78.93.254217.78.93.255126
189217.78.94.0/25217.78.94.1 to 217.78.94.126217.78.94.127126
190217.78.94.128/25217.78.94.129 to 217.78.94.254217.78.94.255126
191217.78.95.0/25217.78.95.1 to 217.78.95.126217.78.95.127126
192217.78.95.128/25217.78.95.129 to 217.78.95.254217.78.95.255126
193217.78.96.0/25217.78.96.1 to 217.78.96.126217.78.96.127126
194217.78.96.128/25217.78.96.129 to 217.78.96.254217.78.96.255126
195217.78.97.0/25217.78.97.1 to 217.78.97.126217.78.97.127126
196217.78.97.128/25217.78.97.129 to 217.78.97.254217.78.97.255126
197217.78.98.0/25217.78.98.1 to 217.78.98.126217.78.98.127126
198217.78.98.128/25217.78.98.129 to 217.78.98.254217.78.98.255126
199217.78.99.0/25217.78.99.1 to 217.78.99.126217.78.99.127126
200217.78.99.128/25217.78.99.129 to 217.78.99.254217.78.99.255126
201217.78.100.0/25217.78.100.1 to 217.78.100.126217.78.100.127126
202217.78.100.128/25217.78.100.129 to 217.78.100.254217.78.100.255126
203217.78.101.0/25217.78.101.1 to 217.78.101.126217.78.101.127126
204217.78.101.128/25217.78.101.129 to 217.78.101.254217.78.101.255126
205217.78.102.0/25217.78.102.1 to 217.78.102.126217.78.102.127126
206217.78.102.128/25217.78.102.129 to 217.78.102.254217.78.102.255126
207217.78.103.0/25217.78.103.1 to 217.78.103.126217.78.103.127126
208217.78.103.128/25217.78.103.129 to 217.78.103.254217.78.103.255126
209217.78.104.0/25217.78.104.1 to 217.78.104.126217.78.104.127126
210217.78.104.128/25217.78.104.129 to 217.78.104.254217.78.104.255126
211217.78.105.0/25217.78.105.1 to 217.78.105.126217.78.105.127126
212217.78.105.128/25217.78.105.129 to 217.78.105.254217.78.105.255126
213217.78.106.0/25217.78.106.1 to 217.78.106.126217.78.106.127126
214217.78.106.128/25217.78.106.129 to 217.78.106.254217.78.106.255126
215217.78.107.0/25217.78.107.1 to 217.78.107.126217.78.107.127126
216217.78.107.128/25217.78.107.129 to 217.78.107.254217.78.107.255126
217217.78.108.0/25217.78.108.1 to 217.78.108.126217.78.108.127126
218217.78.108.128/25217.78.108.129 to 217.78.108.254217.78.108.255126
219217.78.109.0/25217.78.109.1 to 217.78.109.126217.78.109.127126
220217.78.109.128/25217.78.109.129 to 217.78.109.254217.78.109.255126
221217.78.110.0/25217.78.110.1 to 217.78.110.126217.78.110.127126
222217.78.110.128/25217.78.110.129 to 217.78.110.254217.78.110.255126
223217.78.111.0/25217.78.111.1 to 217.78.111.126217.78.111.127126
224217.78.111.128/25217.78.111.129 to 217.78.111.254217.78.111.255126
225217.78.112.0/25217.78.112.1 to 217.78.112.126217.78.112.127126
226217.78.112.128/25217.78.112.129 to 217.78.112.254217.78.112.255126
227217.78.113.0/25217.78.113.1 to 217.78.113.126217.78.113.127126
228217.78.113.128/25217.78.113.129 to 217.78.113.254217.78.113.255126
229217.78.114.0/25217.78.114.1 to 217.78.114.126217.78.114.127126
230217.78.114.128/25217.78.114.129 to 217.78.114.254217.78.114.255126
231217.78.115.0/25217.78.115.1 to 217.78.115.126217.78.115.127126
232217.78.115.128/25217.78.115.129 to 217.78.115.254217.78.115.255126
233217.78.116.0/25217.78.116.1 to 217.78.116.126217.78.116.127126
234217.78.116.128/25217.78.116.129 to 217.78.116.254217.78.116.255126
235217.78.117.0/25217.78.117.1 to 217.78.117.126217.78.117.127126
236217.78.117.128/25217.78.117.129 to 217.78.117.254217.78.117.255126
237217.78.118.0/25217.78.118.1 to 217.78.118.126217.78.118.127126
238217.78.118.128/25217.78.118.129 to 217.78.118.254217.78.118.255126
239217.78.119.0/25217.78.119.1 to 217.78.119.126217.78.119.127126
240217.78.119.128/25217.78.119.129 to 217.78.119.254217.78.119.255126
241217.78.120.0/25217.78.120.1 to 217.78.120.126217.78.120.127126
242217.78.120.128/25217.78.120.129 to 217.78.120.254217.78.120.255126
243217.78.121.0/25217.78.121.1 to 217.78.121.126217.78.121.127126
244217.78.121.128/25217.78.121.129 to 217.78.121.254217.78.121.255126
245217.78.122.0/25217.78.122.1 to 217.78.122.126217.78.122.127126
246217.78.122.128/25217.78.122.129 to 217.78.122.254217.78.122.255126
247217.78.123.0/25217.78.123.1 to 217.78.123.126217.78.123.127126
248217.78.123.128/25217.78.123.129 to 217.78.123.254217.78.123.255126
249217.78.124.0/25217.78.124.1 to 217.78.124.126217.78.124.127126
250217.78.124.128/25217.78.124.129 to 217.78.124.254217.78.124.255126
251217.78.125.0/25217.78.125.1 to 217.78.125.126217.78.125.127126
252217.78.125.128/25217.78.125.129 to 217.78.125.254217.78.125.255126
253217.78.126.0/25217.78.126.1 to 217.78.126.126217.78.126.127126
254217.78.126.128/25217.78.126.129 to 217.78.126.254217.78.126.255126
255217.78.127.0/25217.78.127.1 to 217.78.127.126217.78.127.127126
256217.78.127.128/25217.78.127.129 to 217.78.127.254217.78.127.255126

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.