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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.

Network103.26.0.0/16
Usable hosts65,534
Subnet mask255.255.0.0
Addresses65,536
Network address
103.26.0.0
Broadcast address
103.26.255.255
First usable
103.26.0.1
Last usable
103.26.255.254
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
A (default /8)
As numbers
Hex 671A0000 · Integer 1729757184 to 1729822719
Reverse DNS zone
26.103.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01100111.00011010..00000000.00000000103.26.0.0
Subnet mask11111111.11111111..00000000.00000000255.255.0.0
Network01100111.00011010..00000000.00000000103.26.0.0
Broadcast01100111.00011010..11111111.11111111103.26.255.255
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)

103.26.0.0/16 makes 512 subnets of /25; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1103.26.0.0/25103.26.0.1 to 103.26.0.126103.26.0.127126
2103.26.0.128/25103.26.0.129 to 103.26.0.254103.26.0.255126
3103.26.1.0/25103.26.1.1 to 103.26.1.126103.26.1.127126
4103.26.1.128/25103.26.1.129 to 103.26.1.254103.26.1.255126
5103.26.2.0/25103.26.2.1 to 103.26.2.126103.26.2.127126
6103.26.2.128/25103.26.2.129 to 103.26.2.254103.26.2.255126
7103.26.3.0/25103.26.3.1 to 103.26.3.126103.26.3.127126
8103.26.3.128/25103.26.3.129 to 103.26.3.254103.26.3.255126
9103.26.4.0/25103.26.4.1 to 103.26.4.126103.26.4.127126
10103.26.4.128/25103.26.4.129 to 103.26.4.254103.26.4.255126
11103.26.5.0/25103.26.5.1 to 103.26.5.126103.26.5.127126
12103.26.5.128/25103.26.5.129 to 103.26.5.254103.26.5.255126
13103.26.6.0/25103.26.6.1 to 103.26.6.126103.26.6.127126
14103.26.6.128/25103.26.6.129 to 103.26.6.254103.26.6.255126
15103.26.7.0/25103.26.7.1 to 103.26.7.126103.26.7.127126
16103.26.7.128/25103.26.7.129 to 103.26.7.254103.26.7.255126
17103.26.8.0/25103.26.8.1 to 103.26.8.126103.26.8.127126
18103.26.8.128/25103.26.8.129 to 103.26.8.254103.26.8.255126
19103.26.9.0/25103.26.9.1 to 103.26.9.126103.26.9.127126
20103.26.9.128/25103.26.9.129 to 103.26.9.254103.26.9.255126
21103.26.10.0/25103.26.10.1 to 103.26.10.126103.26.10.127126
22103.26.10.128/25103.26.10.129 to 103.26.10.254103.26.10.255126
23103.26.11.0/25103.26.11.1 to 103.26.11.126103.26.11.127126
24103.26.11.128/25103.26.11.129 to 103.26.11.254103.26.11.255126
25103.26.12.0/25103.26.12.1 to 103.26.12.126103.26.12.127126
26103.26.12.128/25103.26.12.129 to 103.26.12.254103.26.12.255126
27103.26.13.0/25103.26.13.1 to 103.26.13.126103.26.13.127126
28103.26.13.128/25103.26.13.129 to 103.26.13.254103.26.13.255126
29103.26.14.0/25103.26.14.1 to 103.26.14.126103.26.14.127126
30103.26.14.128/25103.26.14.129 to 103.26.14.254103.26.14.255126
31103.26.15.0/25103.26.15.1 to 103.26.15.126103.26.15.127126
32103.26.15.128/25103.26.15.129 to 103.26.15.254103.26.15.255126
33103.26.16.0/25103.26.16.1 to 103.26.16.126103.26.16.127126
34103.26.16.128/25103.26.16.129 to 103.26.16.254103.26.16.255126
35103.26.17.0/25103.26.17.1 to 103.26.17.126103.26.17.127126
36103.26.17.128/25103.26.17.129 to 103.26.17.254103.26.17.255126
37103.26.18.0/25103.26.18.1 to 103.26.18.126103.26.18.127126
38103.26.18.128/25103.26.18.129 to 103.26.18.254103.26.18.255126
39103.26.19.0/25103.26.19.1 to 103.26.19.126103.26.19.127126
40103.26.19.128/25103.26.19.129 to 103.26.19.254103.26.19.255126
41103.26.20.0/25103.26.20.1 to 103.26.20.126103.26.20.127126
42103.26.20.128/25103.26.20.129 to 103.26.20.254103.26.20.255126
43103.26.21.0/25103.26.21.1 to 103.26.21.126103.26.21.127126
44103.26.21.128/25103.26.21.129 to 103.26.21.254103.26.21.255126
45103.26.22.0/25103.26.22.1 to 103.26.22.126103.26.22.127126
46103.26.22.128/25103.26.22.129 to 103.26.22.254103.26.22.255126
47103.26.23.0/25103.26.23.1 to 103.26.23.126103.26.23.127126
48103.26.23.128/25103.26.23.129 to 103.26.23.254103.26.23.255126
49103.26.24.0/25103.26.24.1 to 103.26.24.126103.26.24.127126
50103.26.24.128/25103.26.24.129 to 103.26.24.254103.26.24.255126
51103.26.25.0/25103.26.25.1 to 103.26.25.126103.26.25.127126
52103.26.25.128/25103.26.25.129 to 103.26.25.254103.26.25.255126
53103.26.26.0/25103.26.26.1 to 103.26.26.126103.26.26.127126
54103.26.26.128/25103.26.26.129 to 103.26.26.254103.26.26.255126
55103.26.27.0/25103.26.27.1 to 103.26.27.126103.26.27.127126
56103.26.27.128/25103.26.27.129 to 103.26.27.254103.26.27.255126
57103.26.28.0/25103.26.28.1 to 103.26.28.126103.26.28.127126
58103.26.28.128/25103.26.28.129 to 103.26.28.254103.26.28.255126
59103.26.29.0/25103.26.29.1 to 103.26.29.126103.26.29.127126
60103.26.29.128/25103.26.29.129 to 103.26.29.254103.26.29.255126
61103.26.30.0/25103.26.30.1 to 103.26.30.126103.26.30.127126
62103.26.30.128/25103.26.30.129 to 103.26.30.254103.26.30.255126
63103.26.31.0/25103.26.31.1 to 103.26.31.126103.26.31.127126
64103.26.31.128/25103.26.31.129 to 103.26.31.254103.26.31.255126
65103.26.32.0/25103.26.32.1 to 103.26.32.126103.26.32.127126
66103.26.32.128/25103.26.32.129 to 103.26.32.254103.26.32.255126
67103.26.33.0/25103.26.33.1 to 103.26.33.126103.26.33.127126
68103.26.33.128/25103.26.33.129 to 103.26.33.254103.26.33.255126
69103.26.34.0/25103.26.34.1 to 103.26.34.126103.26.34.127126
70103.26.34.128/25103.26.34.129 to 103.26.34.254103.26.34.255126
71103.26.35.0/25103.26.35.1 to 103.26.35.126103.26.35.127126
72103.26.35.128/25103.26.35.129 to 103.26.35.254103.26.35.255126
73103.26.36.0/25103.26.36.1 to 103.26.36.126103.26.36.127126
74103.26.36.128/25103.26.36.129 to 103.26.36.254103.26.36.255126
75103.26.37.0/25103.26.37.1 to 103.26.37.126103.26.37.127126
76103.26.37.128/25103.26.37.129 to 103.26.37.254103.26.37.255126
77103.26.38.0/25103.26.38.1 to 103.26.38.126103.26.38.127126
78103.26.38.128/25103.26.38.129 to 103.26.38.254103.26.38.255126
79103.26.39.0/25103.26.39.1 to 103.26.39.126103.26.39.127126
80103.26.39.128/25103.26.39.129 to 103.26.39.254103.26.39.255126
81103.26.40.0/25103.26.40.1 to 103.26.40.126103.26.40.127126
82103.26.40.128/25103.26.40.129 to 103.26.40.254103.26.40.255126
83103.26.41.0/25103.26.41.1 to 103.26.41.126103.26.41.127126
84103.26.41.128/25103.26.41.129 to 103.26.41.254103.26.41.255126
85103.26.42.0/25103.26.42.1 to 103.26.42.126103.26.42.127126
86103.26.42.128/25103.26.42.129 to 103.26.42.254103.26.42.255126
87103.26.43.0/25103.26.43.1 to 103.26.43.126103.26.43.127126
88103.26.43.128/25103.26.43.129 to 103.26.43.254103.26.43.255126
89103.26.44.0/25103.26.44.1 to 103.26.44.126103.26.44.127126
90103.26.44.128/25103.26.44.129 to 103.26.44.254103.26.44.255126
91103.26.45.0/25103.26.45.1 to 103.26.45.126103.26.45.127126
92103.26.45.128/25103.26.45.129 to 103.26.45.254103.26.45.255126
93103.26.46.0/25103.26.46.1 to 103.26.46.126103.26.46.127126
94103.26.46.128/25103.26.46.129 to 103.26.46.254103.26.46.255126
95103.26.47.0/25103.26.47.1 to 103.26.47.126103.26.47.127126
96103.26.47.128/25103.26.47.129 to 103.26.47.254103.26.47.255126
97103.26.48.0/25103.26.48.1 to 103.26.48.126103.26.48.127126
98103.26.48.128/25103.26.48.129 to 103.26.48.254103.26.48.255126
99103.26.49.0/25103.26.49.1 to 103.26.49.126103.26.49.127126
100103.26.49.128/25103.26.49.129 to 103.26.49.254103.26.49.255126
101103.26.50.0/25103.26.50.1 to 103.26.50.126103.26.50.127126
102103.26.50.128/25103.26.50.129 to 103.26.50.254103.26.50.255126
103103.26.51.0/25103.26.51.1 to 103.26.51.126103.26.51.127126
104103.26.51.128/25103.26.51.129 to 103.26.51.254103.26.51.255126
105103.26.52.0/25103.26.52.1 to 103.26.52.126103.26.52.127126
106103.26.52.128/25103.26.52.129 to 103.26.52.254103.26.52.255126
107103.26.53.0/25103.26.53.1 to 103.26.53.126103.26.53.127126
108103.26.53.128/25103.26.53.129 to 103.26.53.254103.26.53.255126
109103.26.54.0/25103.26.54.1 to 103.26.54.126103.26.54.127126
110103.26.54.128/25103.26.54.129 to 103.26.54.254103.26.54.255126
111103.26.55.0/25103.26.55.1 to 103.26.55.126103.26.55.127126
112103.26.55.128/25103.26.55.129 to 103.26.55.254103.26.55.255126
113103.26.56.0/25103.26.56.1 to 103.26.56.126103.26.56.127126
114103.26.56.128/25103.26.56.129 to 103.26.56.254103.26.56.255126
115103.26.57.0/25103.26.57.1 to 103.26.57.126103.26.57.127126
116103.26.57.128/25103.26.57.129 to 103.26.57.254103.26.57.255126
117103.26.58.0/25103.26.58.1 to 103.26.58.126103.26.58.127126
118103.26.58.128/25103.26.58.129 to 103.26.58.254103.26.58.255126
119103.26.59.0/25103.26.59.1 to 103.26.59.126103.26.59.127126
120103.26.59.128/25103.26.59.129 to 103.26.59.254103.26.59.255126
121103.26.60.0/25103.26.60.1 to 103.26.60.126103.26.60.127126
122103.26.60.128/25103.26.60.129 to 103.26.60.254103.26.60.255126
123103.26.61.0/25103.26.61.1 to 103.26.61.126103.26.61.127126
124103.26.61.128/25103.26.61.129 to 103.26.61.254103.26.61.255126
125103.26.62.0/25103.26.62.1 to 103.26.62.126103.26.62.127126
126103.26.62.128/25103.26.62.129 to 103.26.62.254103.26.62.255126
127103.26.63.0/25103.26.63.1 to 103.26.63.126103.26.63.127126
128103.26.63.128/25103.26.63.129 to 103.26.63.254103.26.63.255126
129103.26.64.0/25103.26.64.1 to 103.26.64.126103.26.64.127126
130103.26.64.128/25103.26.64.129 to 103.26.64.254103.26.64.255126
131103.26.65.0/25103.26.65.1 to 103.26.65.126103.26.65.127126
132103.26.65.128/25103.26.65.129 to 103.26.65.254103.26.65.255126
133103.26.66.0/25103.26.66.1 to 103.26.66.126103.26.66.127126
134103.26.66.128/25103.26.66.129 to 103.26.66.254103.26.66.255126
135103.26.67.0/25103.26.67.1 to 103.26.67.126103.26.67.127126
136103.26.67.128/25103.26.67.129 to 103.26.67.254103.26.67.255126
137103.26.68.0/25103.26.68.1 to 103.26.68.126103.26.68.127126
138103.26.68.128/25103.26.68.129 to 103.26.68.254103.26.68.255126
139103.26.69.0/25103.26.69.1 to 103.26.69.126103.26.69.127126
140103.26.69.128/25103.26.69.129 to 103.26.69.254103.26.69.255126
141103.26.70.0/25103.26.70.1 to 103.26.70.126103.26.70.127126
142103.26.70.128/25103.26.70.129 to 103.26.70.254103.26.70.255126
143103.26.71.0/25103.26.71.1 to 103.26.71.126103.26.71.127126
144103.26.71.128/25103.26.71.129 to 103.26.71.254103.26.71.255126
145103.26.72.0/25103.26.72.1 to 103.26.72.126103.26.72.127126
146103.26.72.128/25103.26.72.129 to 103.26.72.254103.26.72.255126
147103.26.73.0/25103.26.73.1 to 103.26.73.126103.26.73.127126
148103.26.73.128/25103.26.73.129 to 103.26.73.254103.26.73.255126
149103.26.74.0/25103.26.74.1 to 103.26.74.126103.26.74.127126
150103.26.74.128/25103.26.74.129 to 103.26.74.254103.26.74.255126
151103.26.75.0/25103.26.75.1 to 103.26.75.126103.26.75.127126
152103.26.75.128/25103.26.75.129 to 103.26.75.254103.26.75.255126
153103.26.76.0/25103.26.76.1 to 103.26.76.126103.26.76.127126
154103.26.76.128/25103.26.76.129 to 103.26.76.254103.26.76.255126
155103.26.77.0/25103.26.77.1 to 103.26.77.126103.26.77.127126
156103.26.77.128/25103.26.77.129 to 103.26.77.254103.26.77.255126
157103.26.78.0/25103.26.78.1 to 103.26.78.126103.26.78.127126
158103.26.78.128/25103.26.78.129 to 103.26.78.254103.26.78.255126
159103.26.79.0/25103.26.79.1 to 103.26.79.126103.26.79.127126
160103.26.79.128/25103.26.79.129 to 103.26.79.254103.26.79.255126
161103.26.80.0/25103.26.80.1 to 103.26.80.126103.26.80.127126
162103.26.80.128/25103.26.80.129 to 103.26.80.254103.26.80.255126
163103.26.81.0/25103.26.81.1 to 103.26.81.126103.26.81.127126
164103.26.81.128/25103.26.81.129 to 103.26.81.254103.26.81.255126
165103.26.82.0/25103.26.82.1 to 103.26.82.126103.26.82.127126
166103.26.82.128/25103.26.82.129 to 103.26.82.254103.26.82.255126
167103.26.83.0/25103.26.83.1 to 103.26.83.126103.26.83.127126
168103.26.83.128/25103.26.83.129 to 103.26.83.254103.26.83.255126
169103.26.84.0/25103.26.84.1 to 103.26.84.126103.26.84.127126
170103.26.84.128/25103.26.84.129 to 103.26.84.254103.26.84.255126
171103.26.85.0/25103.26.85.1 to 103.26.85.126103.26.85.127126
172103.26.85.128/25103.26.85.129 to 103.26.85.254103.26.85.255126
173103.26.86.0/25103.26.86.1 to 103.26.86.126103.26.86.127126
174103.26.86.128/25103.26.86.129 to 103.26.86.254103.26.86.255126
175103.26.87.0/25103.26.87.1 to 103.26.87.126103.26.87.127126
176103.26.87.128/25103.26.87.129 to 103.26.87.254103.26.87.255126
177103.26.88.0/25103.26.88.1 to 103.26.88.126103.26.88.127126
178103.26.88.128/25103.26.88.129 to 103.26.88.254103.26.88.255126
179103.26.89.0/25103.26.89.1 to 103.26.89.126103.26.89.127126
180103.26.89.128/25103.26.89.129 to 103.26.89.254103.26.89.255126
181103.26.90.0/25103.26.90.1 to 103.26.90.126103.26.90.127126
182103.26.90.128/25103.26.90.129 to 103.26.90.254103.26.90.255126
183103.26.91.0/25103.26.91.1 to 103.26.91.126103.26.91.127126
184103.26.91.128/25103.26.91.129 to 103.26.91.254103.26.91.255126
185103.26.92.0/25103.26.92.1 to 103.26.92.126103.26.92.127126
186103.26.92.128/25103.26.92.129 to 103.26.92.254103.26.92.255126
187103.26.93.0/25103.26.93.1 to 103.26.93.126103.26.93.127126
188103.26.93.128/25103.26.93.129 to 103.26.93.254103.26.93.255126
189103.26.94.0/25103.26.94.1 to 103.26.94.126103.26.94.127126
190103.26.94.128/25103.26.94.129 to 103.26.94.254103.26.94.255126
191103.26.95.0/25103.26.95.1 to 103.26.95.126103.26.95.127126
192103.26.95.128/25103.26.95.129 to 103.26.95.254103.26.95.255126
193103.26.96.0/25103.26.96.1 to 103.26.96.126103.26.96.127126
194103.26.96.128/25103.26.96.129 to 103.26.96.254103.26.96.255126
195103.26.97.0/25103.26.97.1 to 103.26.97.126103.26.97.127126
196103.26.97.128/25103.26.97.129 to 103.26.97.254103.26.97.255126
197103.26.98.0/25103.26.98.1 to 103.26.98.126103.26.98.127126
198103.26.98.128/25103.26.98.129 to 103.26.98.254103.26.98.255126
199103.26.99.0/25103.26.99.1 to 103.26.99.126103.26.99.127126
200103.26.99.128/25103.26.99.129 to 103.26.99.254103.26.99.255126
201103.26.100.0/25103.26.100.1 to 103.26.100.126103.26.100.127126
202103.26.100.128/25103.26.100.129 to 103.26.100.254103.26.100.255126
203103.26.101.0/25103.26.101.1 to 103.26.101.126103.26.101.127126
204103.26.101.128/25103.26.101.129 to 103.26.101.254103.26.101.255126
205103.26.102.0/25103.26.102.1 to 103.26.102.126103.26.102.127126
206103.26.102.128/25103.26.102.129 to 103.26.102.254103.26.102.255126
207103.26.103.0/25103.26.103.1 to 103.26.103.126103.26.103.127126
208103.26.103.128/25103.26.103.129 to 103.26.103.254103.26.103.255126
209103.26.104.0/25103.26.104.1 to 103.26.104.126103.26.104.127126
210103.26.104.128/25103.26.104.129 to 103.26.104.254103.26.104.255126
211103.26.105.0/25103.26.105.1 to 103.26.105.126103.26.105.127126
212103.26.105.128/25103.26.105.129 to 103.26.105.254103.26.105.255126
213103.26.106.0/25103.26.106.1 to 103.26.106.126103.26.106.127126
214103.26.106.128/25103.26.106.129 to 103.26.106.254103.26.106.255126
215103.26.107.0/25103.26.107.1 to 103.26.107.126103.26.107.127126
216103.26.107.128/25103.26.107.129 to 103.26.107.254103.26.107.255126
217103.26.108.0/25103.26.108.1 to 103.26.108.126103.26.108.127126
218103.26.108.128/25103.26.108.129 to 103.26.108.254103.26.108.255126
219103.26.109.0/25103.26.109.1 to 103.26.109.126103.26.109.127126
220103.26.109.128/25103.26.109.129 to 103.26.109.254103.26.109.255126
221103.26.110.0/25103.26.110.1 to 103.26.110.126103.26.110.127126
222103.26.110.128/25103.26.110.129 to 103.26.110.254103.26.110.255126
223103.26.111.0/25103.26.111.1 to 103.26.111.126103.26.111.127126
224103.26.111.128/25103.26.111.129 to 103.26.111.254103.26.111.255126
225103.26.112.0/25103.26.112.1 to 103.26.112.126103.26.112.127126
226103.26.112.128/25103.26.112.129 to 103.26.112.254103.26.112.255126
227103.26.113.0/25103.26.113.1 to 103.26.113.126103.26.113.127126
228103.26.113.128/25103.26.113.129 to 103.26.113.254103.26.113.255126
229103.26.114.0/25103.26.114.1 to 103.26.114.126103.26.114.127126
230103.26.114.128/25103.26.114.129 to 103.26.114.254103.26.114.255126
231103.26.115.0/25103.26.115.1 to 103.26.115.126103.26.115.127126
232103.26.115.128/25103.26.115.129 to 103.26.115.254103.26.115.255126
233103.26.116.0/25103.26.116.1 to 103.26.116.126103.26.116.127126
234103.26.116.128/25103.26.116.129 to 103.26.116.254103.26.116.255126
235103.26.117.0/25103.26.117.1 to 103.26.117.126103.26.117.127126
236103.26.117.128/25103.26.117.129 to 103.26.117.254103.26.117.255126
237103.26.118.0/25103.26.118.1 to 103.26.118.126103.26.118.127126
238103.26.118.128/25103.26.118.129 to 103.26.118.254103.26.118.255126
239103.26.119.0/25103.26.119.1 to 103.26.119.126103.26.119.127126
240103.26.119.128/25103.26.119.129 to 103.26.119.254103.26.119.255126
241103.26.120.0/25103.26.120.1 to 103.26.120.126103.26.120.127126
242103.26.120.128/25103.26.120.129 to 103.26.120.254103.26.120.255126
243103.26.121.0/25103.26.121.1 to 103.26.121.126103.26.121.127126
244103.26.121.128/25103.26.121.129 to 103.26.121.254103.26.121.255126
245103.26.122.0/25103.26.122.1 to 103.26.122.126103.26.122.127126
246103.26.122.128/25103.26.122.129 to 103.26.122.254103.26.122.255126
247103.26.123.0/25103.26.123.1 to 103.26.123.126103.26.123.127126
248103.26.123.128/25103.26.123.129 to 103.26.123.254103.26.123.255126
249103.26.124.0/25103.26.124.1 to 103.26.124.126103.26.124.127126
250103.26.124.128/25103.26.124.129 to 103.26.124.254103.26.124.255126
251103.26.125.0/25103.26.125.1 to 103.26.125.126103.26.125.127126
252103.26.125.128/25103.26.125.129 to 103.26.125.254103.26.125.255126
253103.26.126.0/25103.26.126.1 to 103.26.126.126103.26.126.127126
254103.26.126.128/25103.26.126.129 to 103.26.126.254103.26.126.255126
255103.26.127.0/25103.26.127.1 to 103.26.127.126103.26.127.127126
256103.26.127.128/25103.26.127.129 to 103.26.127.254103.26.127.255126

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.