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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.

Network138.84.0.0/17
Usable hosts32,766
Subnet mask255.255.128.0
Addresses32,768
Network address
138.84.0.0
Broadcast address
138.84.127.255
First usable
138.84.0.1
Last usable
138.84.127.254
Usable hosts
32,766 (32,768 less the network and broadcast addresses)
Subnet mask
255.255.128.0
Wildcard mask
0.0.127.255 (Cisco ACLs, OSPF)
Prefix length
/17
Type
Public public
Old class
B (default /16)
As numbers
Hex 8A540000 · Integer 2320760832 to 2320793599
Reverse DNS zones
0.84.138.in-addr.arpa
1.84.138.in-addr.arpa
2.84.138.in-addr.arpa
3.84.138.in-addr.arpa
4.84.138.in-addr.arpa
5.84.138.in-addr.arpa
6.84.138.in-addr.arpa
7.84.138.in-addr.arpa
8.84.138.in-addr.arpa
9.84.138.in-addr.arpa
10.84.138.in-addr.arpa
11.84.138.in-addr.arpa
12.84.138.in-addr.arpa
13.84.138.in-addr.arpa
14.84.138.in-addr.arpa
15.84.138.in-addr.arpa
and 112 more
/17 is not on a 8-bit boundary, so it takes 128 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10001010.01010100.00000000.00000000138.84.0.0
Subnet mask11111111.11111111.10000000.00000000255.255.128.0
Network10001010.01010100.00000000.00000000138.84.0.0
Broadcast10001010.01010100.01111111.11111111138.84.127.255
Split into smaller subnets/25
/18 (2)/19 (4)/20 (8)/21 (16)/22 (32)/23 (64)/24 (128)/25 (256)/26 (512)/27 (1,024)/28 (2,048)/29 (4,096)

138.84.0.0/17 makes 256 subnets of /25.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1138.84.0.0/25138.84.0.1 to 138.84.0.126138.84.0.127126
2138.84.0.128/25138.84.0.129 to 138.84.0.254138.84.0.255126
3138.84.1.0/25138.84.1.1 to 138.84.1.126138.84.1.127126
4138.84.1.128/25138.84.1.129 to 138.84.1.254138.84.1.255126
5138.84.2.0/25138.84.2.1 to 138.84.2.126138.84.2.127126
6138.84.2.128/25138.84.2.129 to 138.84.2.254138.84.2.255126
7138.84.3.0/25138.84.3.1 to 138.84.3.126138.84.3.127126
8138.84.3.128/25138.84.3.129 to 138.84.3.254138.84.3.255126
9138.84.4.0/25138.84.4.1 to 138.84.4.126138.84.4.127126
10138.84.4.128/25138.84.4.129 to 138.84.4.254138.84.4.255126
11138.84.5.0/25138.84.5.1 to 138.84.5.126138.84.5.127126
12138.84.5.128/25138.84.5.129 to 138.84.5.254138.84.5.255126
13138.84.6.0/25138.84.6.1 to 138.84.6.126138.84.6.127126
14138.84.6.128/25138.84.6.129 to 138.84.6.254138.84.6.255126
15138.84.7.0/25138.84.7.1 to 138.84.7.126138.84.7.127126
16138.84.7.128/25138.84.7.129 to 138.84.7.254138.84.7.255126
17138.84.8.0/25138.84.8.1 to 138.84.8.126138.84.8.127126
18138.84.8.128/25138.84.8.129 to 138.84.8.254138.84.8.255126
19138.84.9.0/25138.84.9.1 to 138.84.9.126138.84.9.127126
20138.84.9.128/25138.84.9.129 to 138.84.9.254138.84.9.255126
21138.84.10.0/25138.84.10.1 to 138.84.10.126138.84.10.127126
22138.84.10.128/25138.84.10.129 to 138.84.10.254138.84.10.255126
23138.84.11.0/25138.84.11.1 to 138.84.11.126138.84.11.127126
24138.84.11.128/25138.84.11.129 to 138.84.11.254138.84.11.255126
25138.84.12.0/25138.84.12.1 to 138.84.12.126138.84.12.127126
26138.84.12.128/25138.84.12.129 to 138.84.12.254138.84.12.255126
27138.84.13.0/25138.84.13.1 to 138.84.13.126138.84.13.127126
28138.84.13.128/25138.84.13.129 to 138.84.13.254138.84.13.255126
29138.84.14.0/25138.84.14.1 to 138.84.14.126138.84.14.127126
30138.84.14.128/25138.84.14.129 to 138.84.14.254138.84.14.255126
31138.84.15.0/25138.84.15.1 to 138.84.15.126138.84.15.127126
32138.84.15.128/25138.84.15.129 to 138.84.15.254138.84.15.255126
33138.84.16.0/25138.84.16.1 to 138.84.16.126138.84.16.127126
34138.84.16.128/25138.84.16.129 to 138.84.16.254138.84.16.255126
35138.84.17.0/25138.84.17.1 to 138.84.17.126138.84.17.127126
36138.84.17.128/25138.84.17.129 to 138.84.17.254138.84.17.255126
37138.84.18.0/25138.84.18.1 to 138.84.18.126138.84.18.127126
38138.84.18.128/25138.84.18.129 to 138.84.18.254138.84.18.255126
39138.84.19.0/25138.84.19.1 to 138.84.19.126138.84.19.127126
40138.84.19.128/25138.84.19.129 to 138.84.19.254138.84.19.255126
41138.84.20.0/25138.84.20.1 to 138.84.20.126138.84.20.127126
42138.84.20.128/25138.84.20.129 to 138.84.20.254138.84.20.255126
43138.84.21.0/25138.84.21.1 to 138.84.21.126138.84.21.127126
44138.84.21.128/25138.84.21.129 to 138.84.21.254138.84.21.255126
45138.84.22.0/25138.84.22.1 to 138.84.22.126138.84.22.127126
46138.84.22.128/25138.84.22.129 to 138.84.22.254138.84.22.255126
47138.84.23.0/25138.84.23.1 to 138.84.23.126138.84.23.127126
48138.84.23.128/25138.84.23.129 to 138.84.23.254138.84.23.255126
49138.84.24.0/25138.84.24.1 to 138.84.24.126138.84.24.127126
50138.84.24.128/25138.84.24.129 to 138.84.24.254138.84.24.255126
51138.84.25.0/25138.84.25.1 to 138.84.25.126138.84.25.127126
52138.84.25.128/25138.84.25.129 to 138.84.25.254138.84.25.255126
53138.84.26.0/25138.84.26.1 to 138.84.26.126138.84.26.127126
54138.84.26.128/25138.84.26.129 to 138.84.26.254138.84.26.255126
55138.84.27.0/25138.84.27.1 to 138.84.27.126138.84.27.127126
56138.84.27.128/25138.84.27.129 to 138.84.27.254138.84.27.255126
57138.84.28.0/25138.84.28.1 to 138.84.28.126138.84.28.127126
58138.84.28.128/25138.84.28.129 to 138.84.28.254138.84.28.255126
59138.84.29.0/25138.84.29.1 to 138.84.29.126138.84.29.127126
60138.84.29.128/25138.84.29.129 to 138.84.29.254138.84.29.255126
61138.84.30.0/25138.84.30.1 to 138.84.30.126138.84.30.127126
62138.84.30.128/25138.84.30.129 to 138.84.30.254138.84.30.255126
63138.84.31.0/25138.84.31.1 to 138.84.31.126138.84.31.127126
64138.84.31.128/25138.84.31.129 to 138.84.31.254138.84.31.255126
65138.84.32.0/25138.84.32.1 to 138.84.32.126138.84.32.127126
66138.84.32.128/25138.84.32.129 to 138.84.32.254138.84.32.255126
67138.84.33.0/25138.84.33.1 to 138.84.33.126138.84.33.127126
68138.84.33.128/25138.84.33.129 to 138.84.33.254138.84.33.255126
69138.84.34.0/25138.84.34.1 to 138.84.34.126138.84.34.127126
70138.84.34.128/25138.84.34.129 to 138.84.34.254138.84.34.255126
71138.84.35.0/25138.84.35.1 to 138.84.35.126138.84.35.127126
72138.84.35.128/25138.84.35.129 to 138.84.35.254138.84.35.255126
73138.84.36.0/25138.84.36.1 to 138.84.36.126138.84.36.127126
74138.84.36.128/25138.84.36.129 to 138.84.36.254138.84.36.255126
75138.84.37.0/25138.84.37.1 to 138.84.37.126138.84.37.127126
76138.84.37.128/25138.84.37.129 to 138.84.37.254138.84.37.255126
77138.84.38.0/25138.84.38.1 to 138.84.38.126138.84.38.127126
78138.84.38.128/25138.84.38.129 to 138.84.38.254138.84.38.255126
79138.84.39.0/25138.84.39.1 to 138.84.39.126138.84.39.127126
80138.84.39.128/25138.84.39.129 to 138.84.39.254138.84.39.255126
81138.84.40.0/25138.84.40.1 to 138.84.40.126138.84.40.127126
82138.84.40.128/25138.84.40.129 to 138.84.40.254138.84.40.255126
83138.84.41.0/25138.84.41.1 to 138.84.41.126138.84.41.127126
84138.84.41.128/25138.84.41.129 to 138.84.41.254138.84.41.255126
85138.84.42.0/25138.84.42.1 to 138.84.42.126138.84.42.127126
86138.84.42.128/25138.84.42.129 to 138.84.42.254138.84.42.255126
87138.84.43.0/25138.84.43.1 to 138.84.43.126138.84.43.127126
88138.84.43.128/25138.84.43.129 to 138.84.43.254138.84.43.255126
89138.84.44.0/25138.84.44.1 to 138.84.44.126138.84.44.127126
90138.84.44.128/25138.84.44.129 to 138.84.44.254138.84.44.255126
91138.84.45.0/25138.84.45.1 to 138.84.45.126138.84.45.127126
92138.84.45.128/25138.84.45.129 to 138.84.45.254138.84.45.255126
93138.84.46.0/25138.84.46.1 to 138.84.46.126138.84.46.127126
94138.84.46.128/25138.84.46.129 to 138.84.46.254138.84.46.255126
95138.84.47.0/25138.84.47.1 to 138.84.47.126138.84.47.127126
96138.84.47.128/25138.84.47.129 to 138.84.47.254138.84.47.255126
97138.84.48.0/25138.84.48.1 to 138.84.48.126138.84.48.127126
98138.84.48.128/25138.84.48.129 to 138.84.48.254138.84.48.255126
99138.84.49.0/25138.84.49.1 to 138.84.49.126138.84.49.127126
100138.84.49.128/25138.84.49.129 to 138.84.49.254138.84.49.255126
101138.84.50.0/25138.84.50.1 to 138.84.50.126138.84.50.127126
102138.84.50.128/25138.84.50.129 to 138.84.50.254138.84.50.255126
103138.84.51.0/25138.84.51.1 to 138.84.51.126138.84.51.127126
104138.84.51.128/25138.84.51.129 to 138.84.51.254138.84.51.255126
105138.84.52.0/25138.84.52.1 to 138.84.52.126138.84.52.127126
106138.84.52.128/25138.84.52.129 to 138.84.52.254138.84.52.255126
107138.84.53.0/25138.84.53.1 to 138.84.53.126138.84.53.127126
108138.84.53.128/25138.84.53.129 to 138.84.53.254138.84.53.255126
109138.84.54.0/25138.84.54.1 to 138.84.54.126138.84.54.127126
110138.84.54.128/25138.84.54.129 to 138.84.54.254138.84.54.255126
111138.84.55.0/25138.84.55.1 to 138.84.55.126138.84.55.127126
112138.84.55.128/25138.84.55.129 to 138.84.55.254138.84.55.255126
113138.84.56.0/25138.84.56.1 to 138.84.56.126138.84.56.127126
114138.84.56.128/25138.84.56.129 to 138.84.56.254138.84.56.255126
115138.84.57.0/25138.84.57.1 to 138.84.57.126138.84.57.127126
116138.84.57.128/25138.84.57.129 to 138.84.57.254138.84.57.255126
117138.84.58.0/25138.84.58.1 to 138.84.58.126138.84.58.127126
118138.84.58.128/25138.84.58.129 to 138.84.58.254138.84.58.255126
119138.84.59.0/25138.84.59.1 to 138.84.59.126138.84.59.127126
120138.84.59.128/25138.84.59.129 to 138.84.59.254138.84.59.255126
121138.84.60.0/25138.84.60.1 to 138.84.60.126138.84.60.127126
122138.84.60.128/25138.84.60.129 to 138.84.60.254138.84.60.255126
123138.84.61.0/25138.84.61.1 to 138.84.61.126138.84.61.127126
124138.84.61.128/25138.84.61.129 to 138.84.61.254138.84.61.255126
125138.84.62.0/25138.84.62.1 to 138.84.62.126138.84.62.127126
126138.84.62.128/25138.84.62.129 to 138.84.62.254138.84.62.255126
127138.84.63.0/25138.84.63.1 to 138.84.63.126138.84.63.127126
128138.84.63.128/25138.84.63.129 to 138.84.63.254138.84.63.255126
129138.84.64.0/25138.84.64.1 to 138.84.64.126138.84.64.127126
130138.84.64.128/25138.84.64.129 to 138.84.64.254138.84.64.255126
131138.84.65.0/25138.84.65.1 to 138.84.65.126138.84.65.127126
132138.84.65.128/25138.84.65.129 to 138.84.65.254138.84.65.255126
133138.84.66.0/25138.84.66.1 to 138.84.66.126138.84.66.127126
134138.84.66.128/25138.84.66.129 to 138.84.66.254138.84.66.255126
135138.84.67.0/25138.84.67.1 to 138.84.67.126138.84.67.127126
136138.84.67.128/25138.84.67.129 to 138.84.67.254138.84.67.255126
137138.84.68.0/25138.84.68.1 to 138.84.68.126138.84.68.127126
138138.84.68.128/25138.84.68.129 to 138.84.68.254138.84.68.255126
139138.84.69.0/25138.84.69.1 to 138.84.69.126138.84.69.127126
140138.84.69.128/25138.84.69.129 to 138.84.69.254138.84.69.255126
141138.84.70.0/25138.84.70.1 to 138.84.70.126138.84.70.127126
142138.84.70.128/25138.84.70.129 to 138.84.70.254138.84.70.255126
143138.84.71.0/25138.84.71.1 to 138.84.71.126138.84.71.127126
144138.84.71.128/25138.84.71.129 to 138.84.71.254138.84.71.255126
145138.84.72.0/25138.84.72.1 to 138.84.72.126138.84.72.127126
146138.84.72.128/25138.84.72.129 to 138.84.72.254138.84.72.255126
147138.84.73.0/25138.84.73.1 to 138.84.73.126138.84.73.127126
148138.84.73.128/25138.84.73.129 to 138.84.73.254138.84.73.255126
149138.84.74.0/25138.84.74.1 to 138.84.74.126138.84.74.127126
150138.84.74.128/25138.84.74.129 to 138.84.74.254138.84.74.255126
151138.84.75.0/25138.84.75.1 to 138.84.75.126138.84.75.127126
152138.84.75.128/25138.84.75.129 to 138.84.75.254138.84.75.255126
153138.84.76.0/25138.84.76.1 to 138.84.76.126138.84.76.127126
154138.84.76.128/25138.84.76.129 to 138.84.76.254138.84.76.255126
155138.84.77.0/25138.84.77.1 to 138.84.77.126138.84.77.127126
156138.84.77.128/25138.84.77.129 to 138.84.77.254138.84.77.255126
157138.84.78.0/25138.84.78.1 to 138.84.78.126138.84.78.127126
158138.84.78.128/25138.84.78.129 to 138.84.78.254138.84.78.255126
159138.84.79.0/25138.84.79.1 to 138.84.79.126138.84.79.127126
160138.84.79.128/25138.84.79.129 to 138.84.79.254138.84.79.255126
161138.84.80.0/25138.84.80.1 to 138.84.80.126138.84.80.127126
162138.84.80.128/25138.84.80.129 to 138.84.80.254138.84.80.255126
163138.84.81.0/25138.84.81.1 to 138.84.81.126138.84.81.127126
164138.84.81.128/25138.84.81.129 to 138.84.81.254138.84.81.255126
165138.84.82.0/25138.84.82.1 to 138.84.82.126138.84.82.127126
166138.84.82.128/25138.84.82.129 to 138.84.82.254138.84.82.255126
167138.84.83.0/25138.84.83.1 to 138.84.83.126138.84.83.127126
168138.84.83.128/25138.84.83.129 to 138.84.83.254138.84.83.255126
169138.84.84.0/25138.84.84.1 to 138.84.84.126138.84.84.127126
170138.84.84.128/25138.84.84.129 to 138.84.84.254138.84.84.255126
171138.84.85.0/25138.84.85.1 to 138.84.85.126138.84.85.127126
172138.84.85.128/25138.84.85.129 to 138.84.85.254138.84.85.255126
173138.84.86.0/25138.84.86.1 to 138.84.86.126138.84.86.127126
174138.84.86.128/25138.84.86.129 to 138.84.86.254138.84.86.255126
175138.84.87.0/25138.84.87.1 to 138.84.87.126138.84.87.127126
176138.84.87.128/25138.84.87.129 to 138.84.87.254138.84.87.255126
177138.84.88.0/25138.84.88.1 to 138.84.88.126138.84.88.127126
178138.84.88.128/25138.84.88.129 to 138.84.88.254138.84.88.255126
179138.84.89.0/25138.84.89.1 to 138.84.89.126138.84.89.127126
180138.84.89.128/25138.84.89.129 to 138.84.89.254138.84.89.255126
181138.84.90.0/25138.84.90.1 to 138.84.90.126138.84.90.127126
182138.84.90.128/25138.84.90.129 to 138.84.90.254138.84.90.255126
183138.84.91.0/25138.84.91.1 to 138.84.91.126138.84.91.127126
184138.84.91.128/25138.84.91.129 to 138.84.91.254138.84.91.255126
185138.84.92.0/25138.84.92.1 to 138.84.92.126138.84.92.127126
186138.84.92.128/25138.84.92.129 to 138.84.92.254138.84.92.255126
187138.84.93.0/25138.84.93.1 to 138.84.93.126138.84.93.127126
188138.84.93.128/25138.84.93.129 to 138.84.93.254138.84.93.255126
189138.84.94.0/25138.84.94.1 to 138.84.94.126138.84.94.127126
190138.84.94.128/25138.84.94.129 to 138.84.94.254138.84.94.255126
191138.84.95.0/25138.84.95.1 to 138.84.95.126138.84.95.127126
192138.84.95.128/25138.84.95.129 to 138.84.95.254138.84.95.255126
193138.84.96.0/25138.84.96.1 to 138.84.96.126138.84.96.127126
194138.84.96.128/25138.84.96.129 to 138.84.96.254138.84.96.255126
195138.84.97.0/25138.84.97.1 to 138.84.97.126138.84.97.127126
196138.84.97.128/25138.84.97.129 to 138.84.97.254138.84.97.255126
197138.84.98.0/25138.84.98.1 to 138.84.98.126138.84.98.127126
198138.84.98.128/25138.84.98.129 to 138.84.98.254138.84.98.255126
199138.84.99.0/25138.84.99.1 to 138.84.99.126138.84.99.127126
200138.84.99.128/25138.84.99.129 to 138.84.99.254138.84.99.255126
201138.84.100.0/25138.84.100.1 to 138.84.100.126138.84.100.127126
202138.84.100.128/25138.84.100.129 to 138.84.100.254138.84.100.255126
203138.84.101.0/25138.84.101.1 to 138.84.101.126138.84.101.127126
204138.84.101.128/25138.84.101.129 to 138.84.101.254138.84.101.255126
205138.84.102.0/25138.84.102.1 to 138.84.102.126138.84.102.127126
206138.84.102.128/25138.84.102.129 to 138.84.102.254138.84.102.255126
207138.84.103.0/25138.84.103.1 to 138.84.103.126138.84.103.127126
208138.84.103.128/25138.84.103.129 to 138.84.103.254138.84.103.255126
209138.84.104.0/25138.84.104.1 to 138.84.104.126138.84.104.127126
210138.84.104.128/25138.84.104.129 to 138.84.104.254138.84.104.255126
211138.84.105.0/25138.84.105.1 to 138.84.105.126138.84.105.127126
212138.84.105.128/25138.84.105.129 to 138.84.105.254138.84.105.255126
213138.84.106.0/25138.84.106.1 to 138.84.106.126138.84.106.127126
214138.84.106.128/25138.84.106.129 to 138.84.106.254138.84.106.255126
215138.84.107.0/25138.84.107.1 to 138.84.107.126138.84.107.127126
216138.84.107.128/25138.84.107.129 to 138.84.107.254138.84.107.255126
217138.84.108.0/25138.84.108.1 to 138.84.108.126138.84.108.127126
218138.84.108.128/25138.84.108.129 to 138.84.108.254138.84.108.255126
219138.84.109.0/25138.84.109.1 to 138.84.109.126138.84.109.127126
220138.84.109.128/25138.84.109.129 to 138.84.109.254138.84.109.255126
221138.84.110.0/25138.84.110.1 to 138.84.110.126138.84.110.127126
222138.84.110.128/25138.84.110.129 to 138.84.110.254138.84.110.255126
223138.84.111.0/25138.84.111.1 to 138.84.111.126138.84.111.127126
224138.84.111.128/25138.84.111.129 to 138.84.111.254138.84.111.255126
225138.84.112.0/25138.84.112.1 to 138.84.112.126138.84.112.127126
226138.84.112.128/25138.84.112.129 to 138.84.112.254138.84.112.255126
227138.84.113.0/25138.84.113.1 to 138.84.113.126138.84.113.127126
228138.84.113.128/25138.84.113.129 to 138.84.113.254138.84.113.255126
229138.84.114.0/25138.84.114.1 to 138.84.114.126138.84.114.127126
230138.84.114.128/25138.84.114.129 to 138.84.114.254138.84.114.255126
231138.84.115.0/25138.84.115.1 to 138.84.115.126138.84.115.127126
232138.84.115.128/25138.84.115.129 to 138.84.115.254138.84.115.255126
233138.84.116.0/25138.84.116.1 to 138.84.116.126138.84.116.127126
234138.84.116.128/25138.84.116.129 to 138.84.116.254138.84.116.255126
235138.84.117.0/25138.84.117.1 to 138.84.117.126138.84.117.127126
236138.84.117.128/25138.84.117.129 to 138.84.117.254138.84.117.255126
237138.84.118.0/25138.84.118.1 to 138.84.118.126138.84.118.127126
238138.84.118.128/25138.84.118.129 to 138.84.118.254138.84.118.255126
239138.84.119.0/25138.84.119.1 to 138.84.119.126138.84.119.127126
240138.84.119.128/25138.84.119.129 to 138.84.119.254138.84.119.255126
241138.84.120.0/25138.84.120.1 to 138.84.120.126138.84.120.127126
242138.84.120.128/25138.84.120.129 to 138.84.120.254138.84.120.255126
243138.84.121.0/25138.84.121.1 to 138.84.121.126138.84.121.127126
244138.84.121.128/25138.84.121.129 to 138.84.121.254138.84.121.255126
245138.84.122.0/25138.84.122.1 to 138.84.122.126138.84.122.127126
246138.84.122.128/25138.84.122.129 to 138.84.122.254138.84.122.255126
247138.84.123.0/25138.84.123.1 to 138.84.123.126138.84.123.127126
248138.84.123.128/25138.84.123.129 to 138.84.123.254138.84.123.255126
249138.84.124.0/25138.84.124.1 to 138.84.124.126138.84.124.127126
250138.84.124.128/25138.84.124.129 to 138.84.124.254138.84.124.255126
251138.84.125.0/25138.84.125.1 to 138.84.125.126138.84.125.127126
252138.84.125.128/25138.84.125.129 to 138.84.125.254138.84.125.255126
253138.84.126.0/25138.84.126.1 to 138.84.126.126138.84.126.127126
254138.84.126.128/25138.84.126.129 to 138.84.126.254138.84.126.255126
255138.84.127.0/25138.84.127.1 to 138.84.127.126138.84.127.127126
256138.84.127.128/25138.84.127.129 to 138.84.127.254138.84.127.255126

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.