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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.

Network106.131.0.0/17
Usable hosts32,766
Subnet mask255.255.128.0
Addresses32,768
Network address
106.131.0.0
Broadcast address
106.131.127.255
First usable
106.131.0.1
Last usable
106.131.127.254
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
A (default /8)
As numbers
Hex 6A830000 · Integer 1786970112 to 1787002879
Reverse DNS zones
0.131.106.in-addr.arpa
1.131.106.in-addr.arpa
2.131.106.in-addr.arpa
3.131.106.in-addr.arpa
4.131.106.in-addr.arpa
5.131.106.in-addr.arpa
6.131.106.in-addr.arpa
7.131.106.in-addr.arpa
8.131.106.in-addr.arpa
9.131.106.in-addr.arpa
10.131.106.in-addr.arpa
11.131.106.in-addr.arpa
12.131.106.in-addr.arpa
13.131.106.in-addr.arpa
14.131.106.in-addr.arpa
15.131.106.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
Address01101010.10000011.00000000.00000000106.131.0.0
Subnet mask11111111.11111111.10000000.00000000255.255.128.0
Network01101010.10000011.00000000.00000000106.131.0.0
Broadcast01101010.10000011.01111111.11111111106.131.127.255
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)

106.131.0.0/17 makes 256 subnets of /25.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1106.131.0.0/25106.131.0.1 to 106.131.0.126106.131.0.127126
2106.131.0.128/25106.131.0.129 to 106.131.0.254106.131.0.255126
3106.131.1.0/25106.131.1.1 to 106.131.1.126106.131.1.127126
4106.131.1.128/25106.131.1.129 to 106.131.1.254106.131.1.255126
5106.131.2.0/25106.131.2.1 to 106.131.2.126106.131.2.127126
6106.131.2.128/25106.131.2.129 to 106.131.2.254106.131.2.255126
7106.131.3.0/25106.131.3.1 to 106.131.3.126106.131.3.127126
8106.131.3.128/25106.131.3.129 to 106.131.3.254106.131.3.255126
9106.131.4.0/25106.131.4.1 to 106.131.4.126106.131.4.127126
10106.131.4.128/25106.131.4.129 to 106.131.4.254106.131.4.255126
11106.131.5.0/25106.131.5.1 to 106.131.5.126106.131.5.127126
12106.131.5.128/25106.131.5.129 to 106.131.5.254106.131.5.255126
13106.131.6.0/25106.131.6.1 to 106.131.6.126106.131.6.127126
14106.131.6.128/25106.131.6.129 to 106.131.6.254106.131.6.255126
15106.131.7.0/25106.131.7.1 to 106.131.7.126106.131.7.127126
16106.131.7.128/25106.131.7.129 to 106.131.7.254106.131.7.255126
17106.131.8.0/25106.131.8.1 to 106.131.8.126106.131.8.127126
18106.131.8.128/25106.131.8.129 to 106.131.8.254106.131.8.255126
19106.131.9.0/25106.131.9.1 to 106.131.9.126106.131.9.127126
20106.131.9.128/25106.131.9.129 to 106.131.9.254106.131.9.255126
21106.131.10.0/25106.131.10.1 to 106.131.10.126106.131.10.127126
22106.131.10.128/25106.131.10.129 to 106.131.10.254106.131.10.255126
23106.131.11.0/25106.131.11.1 to 106.131.11.126106.131.11.127126
24106.131.11.128/25106.131.11.129 to 106.131.11.254106.131.11.255126
25106.131.12.0/25106.131.12.1 to 106.131.12.126106.131.12.127126
26106.131.12.128/25106.131.12.129 to 106.131.12.254106.131.12.255126
27106.131.13.0/25106.131.13.1 to 106.131.13.126106.131.13.127126
28106.131.13.128/25106.131.13.129 to 106.131.13.254106.131.13.255126
29106.131.14.0/25106.131.14.1 to 106.131.14.126106.131.14.127126
30106.131.14.128/25106.131.14.129 to 106.131.14.254106.131.14.255126
31106.131.15.0/25106.131.15.1 to 106.131.15.126106.131.15.127126
32106.131.15.128/25106.131.15.129 to 106.131.15.254106.131.15.255126
33106.131.16.0/25106.131.16.1 to 106.131.16.126106.131.16.127126
34106.131.16.128/25106.131.16.129 to 106.131.16.254106.131.16.255126
35106.131.17.0/25106.131.17.1 to 106.131.17.126106.131.17.127126
36106.131.17.128/25106.131.17.129 to 106.131.17.254106.131.17.255126
37106.131.18.0/25106.131.18.1 to 106.131.18.126106.131.18.127126
38106.131.18.128/25106.131.18.129 to 106.131.18.254106.131.18.255126
39106.131.19.0/25106.131.19.1 to 106.131.19.126106.131.19.127126
40106.131.19.128/25106.131.19.129 to 106.131.19.254106.131.19.255126
41106.131.20.0/25106.131.20.1 to 106.131.20.126106.131.20.127126
42106.131.20.128/25106.131.20.129 to 106.131.20.254106.131.20.255126
43106.131.21.0/25106.131.21.1 to 106.131.21.126106.131.21.127126
44106.131.21.128/25106.131.21.129 to 106.131.21.254106.131.21.255126
45106.131.22.0/25106.131.22.1 to 106.131.22.126106.131.22.127126
46106.131.22.128/25106.131.22.129 to 106.131.22.254106.131.22.255126
47106.131.23.0/25106.131.23.1 to 106.131.23.126106.131.23.127126
48106.131.23.128/25106.131.23.129 to 106.131.23.254106.131.23.255126
49106.131.24.0/25106.131.24.1 to 106.131.24.126106.131.24.127126
50106.131.24.128/25106.131.24.129 to 106.131.24.254106.131.24.255126
51106.131.25.0/25106.131.25.1 to 106.131.25.126106.131.25.127126
52106.131.25.128/25106.131.25.129 to 106.131.25.254106.131.25.255126
53106.131.26.0/25106.131.26.1 to 106.131.26.126106.131.26.127126
54106.131.26.128/25106.131.26.129 to 106.131.26.254106.131.26.255126
55106.131.27.0/25106.131.27.1 to 106.131.27.126106.131.27.127126
56106.131.27.128/25106.131.27.129 to 106.131.27.254106.131.27.255126
57106.131.28.0/25106.131.28.1 to 106.131.28.126106.131.28.127126
58106.131.28.128/25106.131.28.129 to 106.131.28.254106.131.28.255126
59106.131.29.0/25106.131.29.1 to 106.131.29.126106.131.29.127126
60106.131.29.128/25106.131.29.129 to 106.131.29.254106.131.29.255126
61106.131.30.0/25106.131.30.1 to 106.131.30.126106.131.30.127126
62106.131.30.128/25106.131.30.129 to 106.131.30.254106.131.30.255126
63106.131.31.0/25106.131.31.1 to 106.131.31.126106.131.31.127126
64106.131.31.128/25106.131.31.129 to 106.131.31.254106.131.31.255126
65106.131.32.0/25106.131.32.1 to 106.131.32.126106.131.32.127126
66106.131.32.128/25106.131.32.129 to 106.131.32.254106.131.32.255126
67106.131.33.0/25106.131.33.1 to 106.131.33.126106.131.33.127126
68106.131.33.128/25106.131.33.129 to 106.131.33.254106.131.33.255126
69106.131.34.0/25106.131.34.1 to 106.131.34.126106.131.34.127126
70106.131.34.128/25106.131.34.129 to 106.131.34.254106.131.34.255126
71106.131.35.0/25106.131.35.1 to 106.131.35.126106.131.35.127126
72106.131.35.128/25106.131.35.129 to 106.131.35.254106.131.35.255126
73106.131.36.0/25106.131.36.1 to 106.131.36.126106.131.36.127126
74106.131.36.128/25106.131.36.129 to 106.131.36.254106.131.36.255126
75106.131.37.0/25106.131.37.1 to 106.131.37.126106.131.37.127126
76106.131.37.128/25106.131.37.129 to 106.131.37.254106.131.37.255126
77106.131.38.0/25106.131.38.1 to 106.131.38.126106.131.38.127126
78106.131.38.128/25106.131.38.129 to 106.131.38.254106.131.38.255126
79106.131.39.0/25106.131.39.1 to 106.131.39.126106.131.39.127126
80106.131.39.128/25106.131.39.129 to 106.131.39.254106.131.39.255126
81106.131.40.0/25106.131.40.1 to 106.131.40.126106.131.40.127126
82106.131.40.128/25106.131.40.129 to 106.131.40.254106.131.40.255126
83106.131.41.0/25106.131.41.1 to 106.131.41.126106.131.41.127126
84106.131.41.128/25106.131.41.129 to 106.131.41.254106.131.41.255126
85106.131.42.0/25106.131.42.1 to 106.131.42.126106.131.42.127126
86106.131.42.128/25106.131.42.129 to 106.131.42.254106.131.42.255126
87106.131.43.0/25106.131.43.1 to 106.131.43.126106.131.43.127126
88106.131.43.128/25106.131.43.129 to 106.131.43.254106.131.43.255126
89106.131.44.0/25106.131.44.1 to 106.131.44.126106.131.44.127126
90106.131.44.128/25106.131.44.129 to 106.131.44.254106.131.44.255126
91106.131.45.0/25106.131.45.1 to 106.131.45.126106.131.45.127126
92106.131.45.128/25106.131.45.129 to 106.131.45.254106.131.45.255126
93106.131.46.0/25106.131.46.1 to 106.131.46.126106.131.46.127126
94106.131.46.128/25106.131.46.129 to 106.131.46.254106.131.46.255126
95106.131.47.0/25106.131.47.1 to 106.131.47.126106.131.47.127126
96106.131.47.128/25106.131.47.129 to 106.131.47.254106.131.47.255126
97106.131.48.0/25106.131.48.1 to 106.131.48.126106.131.48.127126
98106.131.48.128/25106.131.48.129 to 106.131.48.254106.131.48.255126
99106.131.49.0/25106.131.49.1 to 106.131.49.126106.131.49.127126
100106.131.49.128/25106.131.49.129 to 106.131.49.254106.131.49.255126
101106.131.50.0/25106.131.50.1 to 106.131.50.126106.131.50.127126
102106.131.50.128/25106.131.50.129 to 106.131.50.254106.131.50.255126
103106.131.51.0/25106.131.51.1 to 106.131.51.126106.131.51.127126
104106.131.51.128/25106.131.51.129 to 106.131.51.254106.131.51.255126
105106.131.52.0/25106.131.52.1 to 106.131.52.126106.131.52.127126
106106.131.52.128/25106.131.52.129 to 106.131.52.254106.131.52.255126
107106.131.53.0/25106.131.53.1 to 106.131.53.126106.131.53.127126
108106.131.53.128/25106.131.53.129 to 106.131.53.254106.131.53.255126
109106.131.54.0/25106.131.54.1 to 106.131.54.126106.131.54.127126
110106.131.54.128/25106.131.54.129 to 106.131.54.254106.131.54.255126
111106.131.55.0/25106.131.55.1 to 106.131.55.126106.131.55.127126
112106.131.55.128/25106.131.55.129 to 106.131.55.254106.131.55.255126
113106.131.56.0/25106.131.56.1 to 106.131.56.126106.131.56.127126
114106.131.56.128/25106.131.56.129 to 106.131.56.254106.131.56.255126
115106.131.57.0/25106.131.57.1 to 106.131.57.126106.131.57.127126
116106.131.57.128/25106.131.57.129 to 106.131.57.254106.131.57.255126
117106.131.58.0/25106.131.58.1 to 106.131.58.126106.131.58.127126
118106.131.58.128/25106.131.58.129 to 106.131.58.254106.131.58.255126
119106.131.59.0/25106.131.59.1 to 106.131.59.126106.131.59.127126
120106.131.59.128/25106.131.59.129 to 106.131.59.254106.131.59.255126
121106.131.60.0/25106.131.60.1 to 106.131.60.126106.131.60.127126
122106.131.60.128/25106.131.60.129 to 106.131.60.254106.131.60.255126
123106.131.61.0/25106.131.61.1 to 106.131.61.126106.131.61.127126
124106.131.61.128/25106.131.61.129 to 106.131.61.254106.131.61.255126
125106.131.62.0/25106.131.62.1 to 106.131.62.126106.131.62.127126
126106.131.62.128/25106.131.62.129 to 106.131.62.254106.131.62.255126
127106.131.63.0/25106.131.63.1 to 106.131.63.126106.131.63.127126
128106.131.63.128/25106.131.63.129 to 106.131.63.254106.131.63.255126
129106.131.64.0/25106.131.64.1 to 106.131.64.126106.131.64.127126
130106.131.64.128/25106.131.64.129 to 106.131.64.254106.131.64.255126
131106.131.65.0/25106.131.65.1 to 106.131.65.126106.131.65.127126
132106.131.65.128/25106.131.65.129 to 106.131.65.254106.131.65.255126
133106.131.66.0/25106.131.66.1 to 106.131.66.126106.131.66.127126
134106.131.66.128/25106.131.66.129 to 106.131.66.254106.131.66.255126
135106.131.67.0/25106.131.67.1 to 106.131.67.126106.131.67.127126
136106.131.67.128/25106.131.67.129 to 106.131.67.254106.131.67.255126
137106.131.68.0/25106.131.68.1 to 106.131.68.126106.131.68.127126
138106.131.68.128/25106.131.68.129 to 106.131.68.254106.131.68.255126
139106.131.69.0/25106.131.69.1 to 106.131.69.126106.131.69.127126
140106.131.69.128/25106.131.69.129 to 106.131.69.254106.131.69.255126
141106.131.70.0/25106.131.70.1 to 106.131.70.126106.131.70.127126
142106.131.70.128/25106.131.70.129 to 106.131.70.254106.131.70.255126
143106.131.71.0/25106.131.71.1 to 106.131.71.126106.131.71.127126
144106.131.71.128/25106.131.71.129 to 106.131.71.254106.131.71.255126
145106.131.72.0/25106.131.72.1 to 106.131.72.126106.131.72.127126
146106.131.72.128/25106.131.72.129 to 106.131.72.254106.131.72.255126
147106.131.73.0/25106.131.73.1 to 106.131.73.126106.131.73.127126
148106.131.73.128/25106.131.73.129 to 106.131.73.254106.131.73.255126
149106.131.74.0/25106.131.74.1 to 106.131.74.126106.131.74.127126
150106.131.74.128/25106.131.74.129 to 106.131.74.254106.131.74.255126
151106.131.75.0/25106.131.75.1 to 106.131.75.126106.131.75.127126
152106.131.75.128/25106.131.75.129 to 106.131.75.254106.131.75.255126
153106.131.76.0/25106.131.76.1 to 106.131.76.126106.131.76.127126
154106.131.76.128/25106.131.76.129 to 106.131.76.254106.131.76.255126
155106.131.77.0/25106.131.77.1 to 106.131.77.126106.131.77.127126
156106.131.77.128/25106.131.77.129 to 106.131.77.254106.131.77.255126
157106.131.78.0/25106.131.78.1 to 106.131.78.126106.131.78.127126
158106.131.78.128/25106.131.78.129 to 106.131.78.254106.131.78.255126
159106.131.79.0/25106.131.79.1 to 106.131.79.126106.131.79.127126
160106.131.79.128/25106.131.79.129 to 106.131.79.254106.131.79.255126
161106.131.80.0/25106.131.80.1 to 106.131.80.126106.131.80.127126
162106.131.80.128/25106.131.80.129 to 106.131.80.254106.131.80.255126
163106.131.81.0/25106.131.81.1 to 106.131.81.126106.131.81.127126
164106.131.81.128/25106.131.81.129 to 106.131.81.254106.131.81.255126
165106.131.82.0/25106.131.82.1 to 106.131.82.126106.131.82.127126
166106.131.82.128/25106.131.82.129 to 106.131.82.254106.131.82.255126
167106.131.83.0/25106.131.83.1 to 106.131.83.126106.131.83.127126
168106.131.83.128/25106.131.83.129 to 106.131.83.254106.131.83.255126
169106.131.84.0/25106.131.84.1 to 106.131.84.126106.131.84.127126
170106.131.84.128/25106.131.84.129 to 106.131.84.254106.131.84.255126
171106.131.85.0/25106.131.85.1 to 106.131.85.126106.131.85.127126
172106.131.85.128/25106.131.85.129 to 106.131.85.254106.131.85.255126
173106.131.86.0/25106.131.86.1 to 106.131.86.126106.131.86.127126
174106.131.86.128/25106.131.86.129 to 106.131.86.254106.131.86.255126
175106.131.87.0/25106.131.87.1 to 106.131.87.126106.131.87.127126
176106.131.87.128/25106.131.87.129 to 106.131.87.254106.131.87.255126
177106.131.88.0/25106.131.88.1 to 106.131.88.126106.131.88.127126
178106.131.88.128/25106.131.88.129 to 106.131.88.254106.131.88.255126
179106.131.89.0/25106.131.89.1 to 106.131.89.126106.131.89.127126
180106.131.89.128/25106.131.89.129 to 106.131.89.254106.131.89.255126
181106.131.90.0/25106.131.90.1 to 106.131.90.126106.131.90.127126
182106.131.90.128/25106.131.90.129 to 106.131.90.254106.131.90.255126
183106.131.91.0/25106.131.91.1 to 106.131.91.126106.131.91.127126
184106.131.91.128/25106.131.91.129 to 106.131.91.254106.131.91.255126
185106.131.92.0/25106.131.92.1 to 106.131.92.126106.131.92.127126
186106.131.92.128/25106.131.92.129 to 106.131.92.254106.131.92.255126
187106.131.93.0/25106.131.93.1 to 106.131.93.126106.131.93.127126
188106.131.93.128/25106.131.93.129 to 106.131.93.254106.131.93.255126
189106.131.94.0/25106.131.94.1 to 106.131.94.126106.131.94.127126
190106.131.94.128/25106.131.94.129 to 106.131.94.254106.131.94.255126
191106.131.95.0/25106.131.95.1 to 106.131.95.126106.131.95.127126
192106.131.95.128/25106.131.95.129 to 106.131.95.254106.131.95.255126
193106.131.96.0/25106.131.96.1 to 106.131.96.126106.131.96.127126
194106.131.96.128/25106.131.96.129 to 106.131.96.254106.131.96.255126
195106.131.97.0/25106.131.97.1 to 106.131.97.126106.131.97.127126
196106.131.97.128/25106.131.97.129 to 106.131.97.254106.131.97.255126
197106.131.98.0/25106.131.98.1 to 106.131.98.126106.131.98.127126
198106.131.98.128/25106.131.98.129 to 106.131.98.254106.131.98.255126
199106.131.99.0/25106.131.99.1 to 106.131.99.126106.131.99.127126
200106.131.99.128/25106.131.99.129 to 106.131.99.254106.131.99.255126
201106.131.100.0/25106.131.100.1 to 106.131.100.126106.131.100.127126
202106.131.100.128/25106.131.100.129 to 106.131.100.254106.131.100.255126
203106.131.101.0/25106.131.101.1 to 106.131.101.126106.131.101.127126
204106.131.101.128/25106.131.101.129 to 106.131.101.254106.131.101.255126
205106.131.102.0/25106.131.102.1 to 106.131.102.126106.131.102.127126
206106.131.102.128/25106.131.102.129 to 106.131.102.254106.131.102.255126
207106.131.103.0/25106.131.103.1 to 106.131.103.126106.131.103.127126
208106.131.103.128/25106.131.103.129 to 106.131.103.254106.131.103.255126
209106.131.104.0/25106.131.104.1 to 106.131.104.126106.131.104.127126
210106.131.104.128/25106.131.104.129 to 106.131.104.254106.131.104.255126
211106.131.105.0/25106.131.105.1 to 106.131.105.126106.131.105.127126
212106.131.105.128/25106.131.105.129 to 106.131.105.254106.131.105.255126
213106.131.106.0/25106.131.106.1 to 106.131.106.126106.131.106.127126
214106.131.106.128/25106.131.106.129 to 106.131.106.254106.131.106.255126
215106.131.107.0/25106.131.107.1 to 106.131.107.126106.131.107.127126
216106.131.107.128/25106.131.107.129 to 106.131.107.254106.131.107.255126
217106.131.108.0/25106.131.108.1 to 106.131.108.126106.131.108.127126
218106.131.108.128/25106.131.108.129 to 106.131.108.254106.131.108.255126
219106.131.109.0/25106.131.109.1 to 106.131.109.126106.131.109.127126
220106.131.109.128/25106.131.109.129 to 106.131.109.254106.131.109.255126
221106.131.110.0/25106.131.110.1 to 106.131.110.126106.131.110.127126
222106.131.110.128/25106.131.110.129 to 106.131.110.254106.131.110.255126
223106.131.111.0/25106.131.111.1 to 106.131.111.126106.131.111.127126
224106.131.111.128/25106.131.111.129 to 106.131.111.254106.131.111.255126
225106.131.112.0/25106.131.112.1 to 106.131.112.126106.131.112.127126
226106.131.112.128/25106.131.112.129 to 106.131.112.254106.131.112.255126
227106.131.113.0/25106.131.113.1 to 106.131.113.126106.131.113.127126
228106.131.113.128/25106.131.113.129 to 106.131.113.254106.131.113.255126
229106.131.114.0/25106.131.114.1 to 106.131.114.126106.131.114.127126
230106.131.114.128/25106.131.114.129 to 106.131.114.254106.131.114.255126
231106.131.115.0/25106.131.115.1 to 106.131.115.126106.131.115.127126
232106.131.115.128/25106.131.115.129 to 106.131.115.254106.131.115.255126
233106.131.116.0/25106.131.116.1 to 106.131.116.126106.131.116.127126
234106.131.116.128/25106.131.116.129 to 106.131.116.254106.131.116.255126
235106.131.117.0/25106.131.117.1 to 106.131.117.126106.131.117.127126
236106.131.117.128/25106.131.117.129 to 106.131.117.254106.131.117.255126
237106.131.118.0/25106.131.118.1 to 106.131.118.126106.131.118.127126
238106.131.118.128/25106.131.118.129 to 106.131.118.254106.131.118.255126
239106.131.119.0/25106.131.119.1 to 106.131.119.126106.131.119.127126
240106.131.119.128/25106.131.119.129 to 106.131.119.254106.131.119.255126
241106.131.120.0/25106.131.120.1 to 106.131.120.126106.131.120.127126
242106.131.120.128/25106.131.120.129 to 106.131.120.254106.131.120.255126
243106.131.121.0/25106.131.121.1 to 106.131.121.126106.131.121.127126
244106.131.121.128/25106.131.121.129 to 106.131.121.254106.131.121.255126
245106.131.122.0/25106.131.122.1 to 106.131.122.126106.131.122.127126
246106.131.122.128/25106.131.122.129 to 106.131.122.254106.131.122.255126
247106.131.123.0/25106.131.123.1 to 106.131.123.126106.131.123.127126
248106.131.123.128/25106.131.123.129 to 106.131.123.254106.131.123.255126
249106.131.124.0/25106.131.124.1 to 106.131.124.126106.131.124.127126
250106.131.124.128/25106.131.124.129 to 106.131.124.254106.131.124.255126
251106.131.125.0/25106.131.125.1 to 106.131.125.126106.131.125.127126
252106.131.125.128/25106.131.125.129 to 106.131.125.254106.131.125.255126
253106.131.126.0/25106.131.126.1 to 106.131.126.126106.131.126.127126
254106.131.126.128/25106.131.126.129 to 106.131.126.254106.131.126.255126
255106.131.127.0/25106.131.127.1 to 106.131.127.126106.131.127.127126
256106.131.127.128/25106.131.127.129 to 106.131.127.254106.131.127.255126

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.