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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.

Network239.0.0.0/9
Usable hosts8,388,606
Subnet mask255.128.0.0
Addresses8,388,608
Network address
239.0.0.0
Broadcast address
239.127.255.255
First usable
239.0.0.1
Last usable
239.127.255.254
Usable hosts
8,388,606 (8,388,608 less the network and broadcast addresses)
Subnet mask
255.128.0.0
Wildcard mask
0.127.255.255 (Cisco ACLs, OSPF)
Prefix length
/9
Type
Multicast 224.0.0.0/4
One-to-many traffic, such as IPTV and routing protocols
Old class
D (multicast)
As numbers
Hex EF000000 · Integer 4009754624 to 4018143231
Reverse DNS zones
0.239.in-addr.arpa
1.239.in-addr.arpa
2.239.in-addr.arpa
3.239.in-addr.arpa
4.239.in-addr.arpa
5.239.in-addr.arpa
6.239.in-addr.arpa
7.239.in-addr.arpa
8.239.in-addr.arpa
9.239.in-addr.arpa
10.239.in-addr.arpa
11.239.in-addr.arpa
12.239.in-addr.arpa
13.239.in-addr.arpa
14.239.in-addr.arpa
15.239.in-addr.arpa
and 112 more
/9 is not on a 8-bit boundary, so it takes 128 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11101111.00000000.00000000.00000000239.0.0.0
Subnet mask11111111.10000000.00000000.00000000255.128.0.0
Network11101111.00000000.00000000.00000000239.0.0.0
Broadcast11101111.01111111.11111111.11111111239.127.255.255
Split into smaller subnets/17
/10 (2)/11 (4)/12 (8)/13 (16)/14 (32)/15 (64)/16 (128)/17 (256)/18 (512)/19 (1,024)/20 (2,048)/21 (4,096)

239.0.0.0/9 makes 256 subnets of /17.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1239.0.0.0/17239.0.0.1 to 239.0.127.254239.0.127.25532,766
2239.0.128.0/17239.0.128.1 to 239.0.255.254239.0.255.25532,766
3239.1.0.0/17239.1.0.1 to 239.1.127.254239.1.127.25532,766
4239.1.128.0/17239.1.128.1 to 239.1.255.254239.1.255.25532,766
5239.2.0.0/17239.2.0.1 to 239.2.127.254239.2.127.25532,766
6239.2.128.0/17239.2.128.1 to 239.2.255.254239.2.255.25532,766
7239.3.0.0/17239.3.0.1 to 239.3.127.254239.3.127.25532,766
8239.3.128.0/17239.3.128.1 to 239.3.255.254239.3.255.25532,766
9239.4.0.0/17239.4.0.1 to 239.4.127.254239.4.127.25532,766
10239.4.128.0/17239.4.128.1 to 239.4.255.254239.4.255.25532,766
11239.5.0.0/17239.5.0.1 to 239.5.127.254239.5.127.25532,766
12239.5.128.0/17239.5.128.1 to 239.5.255.254239.5.255.25532,766
13239.6.0.0/17239.6.0.1 to 239.6.127.254239.6.127.25532,766
14239.6.128.0/17239.6.128.1 to 239.6.255.254239.6.255.25532,766
15239.7.0.0/17239.7.0.1 to 239.7.127.254239.7.127.25532,766
16239.7.128.0/17239.7.128.1 to 239.7.255.254239.7.255.25532,766
17239.8.0.0/17239.8.0.1 to 239.8.127.254239.8.127.25532,766
18239.8.128.0/17239.8.128.1 to 239.8.255.254239.8.255.25532,766
19239.9.0.0/17239.9.0.1 to 239.9.127.254239.9.127.25532,766
20239.9.128.0/17239.9.128.1 to 239.9.255.254239.9.255.25532,766
21239.10.0.0/17239.10.0.1 to 239.10.127.254239.10.127.25532,766
22239.10.128.0/17239.10.128.1 to 239.10.255.254239.10.255.25532,766
23239.11.0.0/17239.11.0.1 to 239.11.127.254239.11.127.25532,766
24239.11.128.0/17239.11.128.1 to 239.11.255.254239.11.255.25532,766
25239.12.0.0/17239.12.0.1 to 239.12.127.254239.12.127.25532,766
26239.12.128.0/17239.12.128.1 to 239.12.255.254239.12.255.25532,766
27239.13.0.0/17239.13.0.1 to 239.13.127.254239.13.127.25532,766
28239.13.128.0/17239.13.128.1 to 239.13.255.254239.13.255.25532,766
29239.14.0.0/17239.14.0.1 to 239.14.127.254239.14.127.25532,766
30239.14.128.0/17239.14.128.1 to 239.14.255.254239.14.255.25532,766
31239.15.0.0/17239.15.0.1 to 239.15.127.254239.15.127.25532,766
32239.15.128.0/17239.15.128.1 to 239.15.255.254239.15.255.25532,766
33239.16.0.0/17239.16.0.1 to 239.16.127.254239.16.127.25532,766
34239.16.128.0/17239.16.128.1 to 239.16.255.254239.16.255.25532,766
35239.17.0.0/17239.17.0.1 to 239.17.127.254239.17.127.25532,766
36239.17.128.0/17239.17.128.1 to 239.17.255.254239.17.255.25532,766
37239.18.0.0/17239.18.0.1 to 239.18.127.254239.18.127.25532,766
38239.18.128.0/17239.18.128.1 to 239.18.255.254239.18.255.25532,766
39239.19.0.0/17239.19.0.1 to 239.19.127.254239.19.127.25532,766
40239.19.128.0/17239.19.128.1 to 239.19.255.254239.19.255.25532,766
41239.20.0.0/17239.20.0.1 to 239.20.127.254239.20.127.25532,766
42239.20.128.0/17239.20.128.1 to 239.20.255.254239.20.255.25532,766
43239.21.0.0/17239.21.0.1 to 239.21.127.254239.21.127.25532,766
44239.21.128.0/17239.21.128.1 to 239.21.255.254239.21.255.25532,766
45239.22.0.0/17239.22.0.1 to 239.22.127.254239.22.127.25532,766
46239.22.128.0/17239.22.128.1 to 239.22.255.254239.22.255.25532,766
47239.23.0.0/17239.23.0.1 to 239.23.127.254239.23.127.25532,766
48239.23.128.0/17239.23.128.1 to 239.23.255.254239.23.255.25532,766
49239.24.0.0/17239.24.0.1 to 239.24.127.254239.24.127.25532,766
50239.24.128.0/17239.24.128.1 to 239.24.255.254239.24.255.25532,766
51239.25.0.0/17239.25.0.1 to 239.25.127.254239.25.127.25532,766
52239.25.128.0/17239.25.128.1 to 239.25.255.254239.25.255.25532,766
53239.26.0.0/17239.26.0.1 to 239.26.127.254239.26.127.25532,766
54239.26.128.0/17239.26.128.1 to 239.26.255.254239.26.255.25532,766
55239.27.0.0/17239.27.0.1 to 239.27.127.254239.27.127.25532,766
56239.27.128.0/17239.27.128.1 to 239.27.255.254239.27.255.25532,766
57239.28.0.0/17239.28.0.1 to 239.28.127.254239.28.127.25532,766
58239.28.128.0/17239.28.128.1 to 239.28.255.254239.28.255.25532,766
59239.29.0.0/17239.29.0.1 to 239.29.127.254239.29.127.25532,766
60239.29.128.0/17239.29.128.1 to 239.29.255.254239.29.255.25532,766
61239.30.0.0/17239.30.0.1 to 239.30.127.254239.30.127.25532,766
62239.30.128.0/17239.30.128.1 to 239.30.255.254239.30.255.25532,766
63239.31.0.0/17239.31.0.1 to 239.31.127.254239.31.127.25532,766
64239.31.128.0/17239.31.128.1 to 239.31.255.254239.31.255.25532,766
65239.32.0.0/17239.32.0.1 to 239.32.127.254239.32.127.25532,766
66239.32.128.0/17239.32.128.1 to 239.32.255.254239.32.255.25532,766
67239.33.0.0/17239.33.0.1 to 239.33.127.254239.33.127.25532,766
68239.33.128.0/17239.33.128.1 to 239.33.255.254239.33.255.25532,766
69239.34.0.0/17239.34.0.1 to 239.34.127.254239.34.127.25532,766
70239.34.128.0/17239.34.128.1 to 239.34.255.254239.34.255.25532,766
71239.35.0.0/17239.35.0.1 to 239.35.127.254239.35.127.25532,766
72239.35.128.0/17239.35.128.1 to 239.35.255.254239.35.255.25532,766
73239.36.0.0/17239.36.0.1 to 239.36.127.254239.36.127.25532,766
74239.36.128.0/17239.36.128.1 to 239.36.255.254239.36.255.25532,766
75239.37.0.0/17239.37.0.1 to 239.37.127.254239.37.127.25532,766
76239.37.128.0/17239.37.128.1 to 239.37.255.254239.37.255.25532,766
77239.38.0.0/17239.38.0.1 to 239.38.127.254239.38.127.25532,766
78239.38.128.0/17239.38.128.1 to 239.38.255.254239.38.255.25532,766
79239.39.0.0/17239.39.0.1 to 239.39.127.254239.39.127.25532,766
80239.39.128.0/17239.39.128.1 to 239.39.255.254239.39.255.25532,766
81239.40.0.0/17239.40.0.1 to 239.40.127.254239.40.127.25532,766
82239.40.128.0/17239.40.128.1 to 239.40.255.254239.40.255.25532,766
83239.41.0.0/17239.41.0.1 to 239.41.127.254239.41.127.25532,766
84239.41.128.0/17239.41.128.1 to 239.41.255.254239.41.255.25532,766
85239.42.0.0/17239.42.0.1 to 239.42.127.254239.42.127.25532,766
86239.42.128.0/17239.42.128.1 to 239.42.255.254239.42.255.25532,766
87239.43.0.0/17239.43.0.1 to 239.43.127.254239.43.127.25532,766
88239.43.128.0/17239.43.128.1 to 239.43.255.254239.43.255.25532,766
89239.44.0.0/17239.44.0.1 to 239.44.127.254239.44.127.25532,766
90239.44.128.0/17239.44.128.1 to 239.44.255.254239.44.255.25532,766
91239.45.0.0/17239.45.0.1 to 239.45.127.254239.45.127.25532,766
92239.45.128.0/17239.45.128.1 to 239.45.255.254239.45.255.25532,766
93239.46.0.0/17239.46.0.1 to 239.46.127.254239.46.127.25532,766
94239.46.128.0/17239.46.128.1 to 239.46.255.254239.46.255.25532,766
95239.47.0.0/17239.47.0.1 to 239.47.127.254239.47.127.25532,766
96239.47.128.0/17239.47.128.1 to 239.47.255.254239.47.255.25532,766
97239.48.0.0/17239.48.0.1 to 239.48.127.254239.48.127.25532,766
98239.48.128.0/17239.48.128.1 to 239.48.255.254239.48.255.25532,766
99239.49.0.0/17239.49.0.1 to 239.49.127.254239.49.127.25532,766
100239.49.128.0/17239.49.128.1 to 239.49.255.254239.49.255.25532,766
101239.50.0.0/17239.50.0.1 to 239.50.127.254239.50.127.25532,766
102239.50.128.0/17239.50.128.1 to 239.50.255.254239.50.255.25532,766
103239.51.0.0/17239.51.0.1 to 239.51.127.254239.51.127.25532,766
104239.51.128.0/17239.51.128.1 to 239.51.255.254239.51.255.25532,766
105239.52.0.0/17239.52.0.1 to 239.52.127.254239.52.127.25532,766
106239.52.128.0/17239.52.128.1 to 239.52.255.254239.52.255.25532,766
107239.53.0.0/17239.53.0.1 to 239.53.127.254239.53.127.25532,766
108239.53.128.0/17239.53.128.1 to 239.53.255.254239.53.255.25532,766
109239.54.0.0/17239.54.0.1 to 239.54.127.254239.54.127.25532,766
110239.54.128.0/17239.54.128.1 to 239.54.255.254239.54.255.25532,766
111239.55.0.0/17239.55.0.1 to 239.55.127.254239.55.127.25532,766
112239.55.128.0/17239.55.128.1 to 239.55.255.254239.55.255.25532,766
113239.56.0.0/17239.56.0.1 to 239.56.127.254239.56.127.25532,766
114239.56.128.0/17239.56.128.1 to 239.56.255.254239.56.255.25532,766
115239.57.0.0/17239.57.0.1 to 239.57.127.254239.57.127.25532,766
116239.57.128.0/17239.57.128.1 to 239.57.255.254239.57.255.25532,766
117239.58.0.0/17239.58.0.1 to 239.58.127.254239.58.127.25532,766
118239.58.128.0/17239.58.128.1 to 239.58.255.254239.58.255.25532,766
119239.59.0.0/17239.59.0.1 to 239.59.127.254239.59.127.25532,766
120239.59.128.0/17239.59.128.1 to 239.59.255.254239.59.255.25532,766
121239.60.0.0/17239.60.0.1 to 239.60.127.254239.60.127.25532,766
122239.60.128.0/17239.60.128.1 to 239.60.255.254239.60.255.25532,766
123239.61.0.0/17239.61.0.1 to 239.61.127.254239.61.127.25532,766
124239.61.128.0/17239.61.128.1 to 239.61.255.254239.61.255.25532,766
125239.62.0.0/17239.62.0.1 to 239.62.127.254239.62.127.25532,766
126239.62.128.0/17239.62.128.1 to 239.62.255.254239.62.255.25532,766
127239.63.0.0/17239.63.0.1 to 239.63.127.254239.63.127.25532,766
128239.63.128.0/17239.63.128.1 to 239.63.255.254239.63.255.25532,766
129239.64.0.0/17239.64.0.1 to 239.64.127.254239.64.127.25532,766
130239.64.128.0/17239.64.128.1 to 239.64.255.254239.64.255.25532,766
131239.65.0.0/17239.65.0.1 to 239.65.127.254239.65.127.25532,766
132239.65.128.0/17239.65.128.1 to 239.65.255.254239.65.255.25532,766
133239.66.0.0/17239.66.0.1 to 239.66.127.254239.66.127.25532,766
134239.66.128.0/17239.66.128.1 to 239.66.255.254239.66.255.25532,766
135239.67.0.0/17239.67.0.1 to 239.67.127.254239.67.127.25532,766
136239.67.128.0/17239.67.128.1 to 239.67.255.254239.67.255.25532,766
137239.68.0.0/17239.68.0.1 to 239.68.127.254239.68.127.25532,766
138239.68.128.0/17239.68.128.1 to 239.68.255.254239.68.255.25532,766
139239.69.0.0/17239.69.0.1 to 239.69.127.254239.69.127.25532,766
140239.69.128.0/17239.69.128.1 to 239.69.255.254239.69.255.25532,766
141239.70.0.0/17239.70.0.1 to 239.70.127.254239.70.127.25532,766
142239.70.128.0/17239.70.128.1 to 239.70.255.254239.70.255.25532,766
143239.71.0.0/17239.71.0.1 to 239.71.127.254239.71.127.25532,766
144239.71.128.0/17239.71.128.1 to 239.71.255.254239.71.255.25532,766
145239.72.0.0/17239.72.0.1 to 239.72.127.254239.72.127.25532,766
146239.72.128.0/17239.72.128.1 to 239.72.255.254239.72.255.25532,766
147239.73.0.0/17239.73.0.1 to 239.73.127.254239.73.127.25532,766
148239.73.128.0/17239.73.128.1 to 239.73.255.254239.73.255.25532,766
149239.74.0.0/17239.74.0.1 to 239.74.127.254239.74.127.25532,766
150239.74.128.0/17239.74.128.1 to 239.74.255.254239.74.255.25532,766
151239.75.0.0/17239.75.0.1 to 239.75.127.254239.75.127.25532,766
152239.75.128.0/17239.75.128.1 to 239.75.255.254239.75.255.25532,766
153239.76.0.0/17239.76.0.1 to 239.76.127.254239.76.127.25532,766
154239.76.128.0/17239.76.128.1 to 239.76.255.254239.76.255.25532,766
155239.77.0.0/17239.77.0.1 to 239.77.127.254239.77.127.25532,766
156239.77.128.0/17239.77.128.1 to 239.77.255.254239.77.255.25532,766
157239.78.0.0/17239.78.0.1 to 239.78.127.254239.78.127.25532,766
158239.78.128.0/17239.78.128.1 to 239.78.255.254239.78.255.25532,766
159239.79.0.0/17239.79.0.1 to 239.79.127.254239.79.127.25532,766
160239.79.128.0/17239.79.128.1 to 239.79.255.254239.79.255.25532,766
161239.80.0.0/17239.80.0.1 to 239.80.127.254239.80.127.25532,766
162239.80.128.0/17239.80.128.1 to 239.80.255.254239.80.255.25532,766
163239.81.0.0/17239.81.0.1 to 239.81.127.254239.81.127.25532,766
164239.81.128.0/17239.81.128.1 to 239.81.255.254239.81.255.25532,766
165239.82.0.0/17239.82.0.1 to 239.82.127.254239.82.127.25532,766
166239.82.128.0/17239.82.128.1 to 239.82.255.254239.82.255.25532,766
167239.83.0.0/17239.83.0.1 to 239.83.127.254239.83.127.25532,766
168239.83.128.0/17239.83.128.1 to 239.83.255.254239.83.255.25532,766
169239.84.0.0/17239.84.0.1 to 239.84.127.254239.84.127.25532,766
170239.84.128.0/17239.84.128.1 to 239.84.255.254239.84.255.25532,766
171239.85.0.0/17239.85.0.1 to 239.85.127.254239.85.127.25532,766
172239.85.128.0/17239.85.128.1 to 239.85.255.254239.85.255.25532,766
173239.86.0.0/17239.86.0.1 to 239.86.127.254239.86.127.25532,766
174239.86.128.0/17239.86.128.1 to 239.86.255.254239.86.255.25532,766
175239.87.0.0/17239.87.0.1 to 239.87.127.254239.87.127.25532,766
176239.87.128.0/17239.87.128.1 to 239.87.255.254239.87.255.25532,766
177239.88.0.0/17239.88.0.1 to 239.88.127.254239.88.127.25532,766
178239.88.128.0/17239.88.128.1 to 239.88.255.254239.88.255.25532,766
179239.89.0.0/17239.89.0.1 to 239.89.127.254239.89.127.25532,766
180239.89.128.0/17239.89.128.1 to 239.89.255.254239.89.255.25532,766
181239.90.0.0/17239.90.0.1 to 239.90.127.254239.90.127.25532,766
182239.90.128.0/17239.90.128.1 to 239.90.255.254239.90.255.25532,766
183239.91.0.0/17239.91.0.1 to 239.91.127.254239.91.127.25532,766
184239.91.128.0/17239.91.128.1 to 239.91.255.254239.91.255.25532,766
185239.92.0.0/17239.92.0.1 to 239.92.127.254239.92.127.25532,766
186239.92.128.0/17239.92.128.1 to 239.92.255.254239.92.255.25532,766
187239.93.0.0/17239.93.0.1 to 239.93.127.254239.93.127.25532,766
188239.93.128.0/17239.93.128.1 to 239.93.255.254239.93.255.25532,766
189239.94.0.0/17239.94.0.1 to 239.94.127.254239.94.127.25532,766
190239.94.128.0/17239.94.128.1 to 239.94.255.254239.94.255.25532,766
191239.95.0.0/17239.95.0.1 to 239.95.127.254239.95.127.25532,766
192239.95.128.0/17239.95.128.1 to 239.95.255.254239.95.255.25532,766
193239.96.0.0/17239.96.0.1 to 239.96.127.254239.96.127.25532,766
194239.96.128.0/17239.96.128.1 to 239.96.255.254239.96.255.25532,766
195239.97.0.0/17239.97.0.1 to 239.97.127.254239.97.127.25532,766
196239.97.128.0/17239.97.128.1 to 239.97.255.254239.97.255.25532,766
197239.98.0.0/17239.98.0.1 to 239.98.127.254239.98.127.25532,766
198239.98.128.0/17239.98.128.1 to 239.98.255.254239.98.255.25532,766
199239.99.0.0/17239.99.0.1 to 239.99.127.254239.99.127.25532,766
200239.99.128.0/17239.99.128.1 to 239.99.255.254239.99.255.25532,766
201239.100.0.0/17239.100.0.1 to 239.100.127.254239.100.127.25532,766
202239.100.128.0/17239.100.128.1 to 239.100.255.254239.100.255.25532,766
203239.101.0.0/17239.101.0.1 to 239.101.127.254239.101.127.25532,766
204239.101.128.0/17239.101.128.1 to 239.101.255.254239.101.255.25532,766
205239.102.0.0/17239.102.0.1 to 239.102.127.254239.102.127.25532,766
206239.102.128.0/17239.102.128.1 to 239.102.255.254239.102.255.25532,766
207239.103.0.0/17239.103.0.1 to 239.103.127.254239.103.127.25532,766
208239.103.128.0/17239.103.128.1 to 239.103.255.254239.103.255.25532,766
209239.104.0.0/17239.104.0.1 to 239.104.127.254239.104.127.25532,766
210239.104.128.0/17239.104.128.1 to 239.104.255.254239.104.255.25532,766
211239.105.0.0/17239.105.0.1 to 239.105.127.254239.105.127.25532,766
212239.105.128.0/17239.105.128.1 to 239.105.255.254239.105.255.25532,766
213239.106.0.0/17239.106.0.1 to 239.106.127.254239.106.127.25532,766
214239.106.128.0/17239.106.128.1 to 239.106.255.254239.106.255.25532,766
215239.107.0.0/17239.107.0.1 to 239.107.127.254239.107.127.25532,766
216239.107.128.0/17239.107.128.1 to 239.107.255.254239.107.255.25532,766
217239.108.0.0/17239.108.0.1 to 239.108.127.254239.108.127.25532,766
218239.108.128.0/17239.108.128.1 to 239.108.255.254239.108.255.25532,766
219239.109.0.0/17239.109.0.1 to 239.109.127.254239.109.127.25532,766
220239.109.128.0/17239.109.128.1 to 239.109.255.254239.109.255.25532,766
221239.110.0.0/17239.110.0.1 to 239.110.127.254239.110.127.25532,766
222239.110.128.0/17239.110.128.1 to 239.110.255.254239.110.255.25532,766
223239.111.0.0/17239.111.0.1 to 239.111.127.254239.111.127.25532,766
224239.111.128.0/17239.111.128.1 to 239.111.255.254239.111.255.25532,766
225239.112.0.0/17239.112.0.1 to 239.112.127.254239.112.127.25532,766
226239.112.128.0/17239.112.128.1 to 239.112.255.254239.112.255.25532,766
227239.113.0.0/17239.113.0.1 to 239.113.127.254239.113.127.25532,766
228239.113.128.0/17239.113.128.1 to 239.113.255.254239.113.255.25532,766
229239.114.0.0/17239.114.0.1 to 239.114.127.254239.114.127.25532,766
230239.114.128.0/17239.114.128.1 to 239.114.255.254239.114.255.25532,766
231239.115.0.0/17239.115.0.1 to 239.115.127.254239.115.127.25532,766
232239.115.128.0/17239.115.128.1 to 239.115.255.254239.115.255.25532,766
233239.116.0.0/17239.116.0.1 to 239.116.127.254239.116.127.25532,766
234239.116.128.0/17239.116.128.1 to 239.116.255.254239.116.255.25532,766
235239.117.0.0/17239.117.0.1 to 239.117.127.254239.117.127.25532,766
236239.117.128.0/17239.117.128.1 to 239.117.255.254239.117.255.25532,766
237239.118.0.0/17239.118.0.1 to 239.118.127.254239.118.127.25532,766
238239.118.128.0/17239.118.128.1 to 239.118.255.254239.118.255.25532,766
239239.119.0.0/17239.119.0.1 to 239.119.127.254239.119.127.25532,766
240239.119.128.0/17239.119.128.1 to 239.119.255.254239.119.255.25532,766
241239.120.0.0/17239.120.0.1 to 239.120.127.254239.120.127.25532,766
242239.120.128.0/17239.120.128.1 to 239.120.255.254239.120.255.25532,766
243239.121.0.0/17239.121.0.1 to 239.121.127.254239.121.127.25532,766
244239.121.128.0/17239.121.128.1 to 239.121.255.254239.121.255.25532,766
245239.122.0.0/17239.122.0.1 to 239.122.127.254239.122.127.25532,766
246239.122.128.0/17239.122.128.1 to 239.122.255.254239.122.255.25532,766
247239.123.0.0/17239.123.0.1 to 239.123.127.254239.123.127.25532,766
248239.123.128.0/17239.123.128.1 to 239.123.255.254239.123.255.25532,766
249239.124.0.0/17239.124.0.1 to 239.124.127.254239.124.127.25532,766
250239.124.128.0/17239.124.128.1 to 239.124.255.254239.124.255.25532,766
251239.125.0.0/17239.125.0.1 to 239.125.127.254239.125.127.25532,766
252239.125.128.0/17239.125.128.1 to 239.125.255.254239.125.255.25532,766
253239.126.0.0/17239.126.0.1 to 239.126.127.254239.126.127.25532,766
254239.126.128.0/17239.126.128.1 to 239.126.255.254239.126.255.25532,766
255239.127.0.0/17239.127.0.1 to 239.127.127.254239.127.127.25532,766
256239.127.128.0/17239.127.128.1 to 239.127.255.254239.127.255.25532,766

IPv4 CIDR reference (/0 to /32)

IPv4 prefix lengths
PrefixSubnet maskWildcardAddressesUsable hostsSizeTypical use
/00.0.0.0255.255.255.2554,294,967,2964,294,967,29416,777,216 × /24
/1128.0.0.0127.255.255.2552,147,483,6482,147,483,6468,388,608 × /24
/2192.0.0.063.255.255.2551,073,741,8241,073,741,8224,194,304 × /24
/3224.0.0.031.255.255.255536,870,912536,870,9102,097,152 × /24
/4240.0.0.015.255.255.255268,435,456268,435,4541,048,576 × /24
/5248.0.0.07.255.255.255134,217,728134,217,726524,288 × /24
/6252.0.0.03.255.255.25567,108,86467,108,862262,144 × /24
/7254.0.0.01.255.255.25533,554,43233,554,430131,072 × /24
/8255.0.0.00.255.255.25516,777,21616,777,21465,536 × /24Old class A; 10.0.0.0/8
/9255.128.0.00.127.255.2558,388,6088,388,60632,768 × /24
/10255.192.0.00.63.255.2554,194,3044,194,30216,384 × /24
/11255.224.0.00.31.255.2552,097,1522,097,1508,192 × /24
/12255.240.0.00.15.255.2551,048,5761,048,5744,096 × /24172.16.0.0/12
/13255.248.0.00.7.255.255524,288524,2862,048 × /24
/14255.252.0.00.3.255.255262,144262,1421,024 × /24
/15255.254.0.00.1.255.255131,072131,070512 × /24
/16255.255.0.00.0.255.25565,53665,534256 × /24Old class B; 192.168.0.0/16
/17255.255.128.00.0.127.25532,76832,766128 × /24
/18255.255.192.00.0.63.25516,38416,38264 × /24
/19255.255.224.00.0.31.2558,1928,19032 × /24
/20255.255.240.00.0.15.2554,0964,09416 × /24
/21255.255.248.00.0.7.2552,0482,0468 × /24
/22255.255.252.00.0.3.2551,0241,0224 × /24Large office or guest Wi-Fi (1,022 hosts)
/23255.255.254.00.0.1.2555125102 × /24Larger office LAN (510 hosts)
/24255.255.255.00.0.0.2552562541 × /24Typical office LAN (old class C)
/25255.255.255.1280.0.0.1271281261/2 of a /24Smaller LAN or VLAN
/26255.255.255.1920.0.0.6364621/4 of a /24Smaller LAN or VLAN
/27255.255.255.2240.0.0.3132301/8 of a /24Small VLAN, phones, cameras
/28255.255.255.2400.0.0.1516141/16 of a /24Small VLAN, phones, cameras
/29255.255.255.2480.0.0.7861/32 of a /24Small fixed public block (5 usable)
/30255.255.255.2520.0.0.3421/64 of a /24Point-to-point (old style)
/31255.255.255.2540.0.0.1221/128 of a /24Point-to-point link (RFC 3021)
/32255.255.255.2550.0.0.0111/256 of a /24One host

IPv6 prefix reference

IPv6 prefix lengths
PrefixAddresses/64 LANs/48 sitesNibbleTypical use
/342,535,295,865,117,307,932,921,825,928,971,026,432 (2^125)2,305,843,009,213,693,95235,184,372,088,832NoAll global unicast (2000::/3)
/165,192,296,858,534,827,628,530,496,329,220,096 (2^112)281,474,976,710,6564,294,967,296Yes
/20324,518,553,658,426,726,783,156,020,576,256 (2^108)17,592,186,044,416268,435,456YesLarge provider allocation (RIPE minimum for some)
/29633,825,300,114,114,700,748,351,602,688 (2^99)34,359,738,368524,288NoRIPE allocation to a provider (often)
/3279,228,162,514,264,337,593,543,950,336 (2^96)4,294,967,29665,536YesProvider allocation (RIPE default)
/364,951,760,157,141,521,099,596,496,896 (2^92)268,435,4564,096Yes
/40309,485,009,821,345,068,724,781,056 (2^88)16,777,216256Yes
/4419,342,813,113,834,066,795,298,816 (2^84)1,048,57616Yes
/481,208,925,819,614,629,174,706,176 (2^80)65,5361YesOne site or organisation (RIPE PI / assignment)
/5275,557,863,725,914,323,419,136 (2^76)4,096Yes
/564,722,366,482,869,645,213,696 (2^72)256YesSmall site or home (common provider assignment)
/60295,147,905,179,352,825,856 (2^68)16YesSome home broadband (16 LANs)
/6418,446,744,073,709,551,616 (2^64)1YesOne LAN or VLAN (needed for SLAAC)
/7272,057,594,037,927,936 (2^56)1/256 of a /64Yes
/80281,474,976,710,656 (2^48)1/65,536 of a /64Yes
/964,294,967,2961/4,294,967,296 of a /64YesEmbeds an IPv4 address (NAT64)
/11265,5361/281,474,976,710,656 of a /64Yes
/1202561/72,057,594,037,927,936 of a /64Yes
/124161/1,152,921,504,606,846,976 of a /64Yes
/12641/4,611,686,018,427,387,904 of a /64No
/12721/9,223,372,036,854,775,808 of a /64NoPoint-to-point link (RFC 6164)
/12811/18,446,744,073,709,551,616 of a /64YesOne host or loopback

Private and special ranges

IPv4

Special-purpose ranges
RangeNameWhat it is
255.255.255.255/32Limited broadcastEvery host on the local network
0.0.0.0/8This networkNot routed; 0.0.0.0 means "any address" in settings
10.0.0.0/8Private (RFC 1918)Office and home networks; not routed on the internet
100.64.0.0/10Shared address space (CGNAT)Used by providers behind carrier-grade NAT (RFC 6598)
127.0.0.0/8LoopbackThis computer
169.254.0.0/16Link-local (APIPA)Self-assigned when no DHCP server answers
172.16.0.0/12Private (RFC 1918)Office and home networks; not routed on the internet
192.0.0.0/24IETF protocol assignmentsSpecial uses such as DS-Lite
192.0.2.0/24Documentation (TEST-NET-1)For examples; never used on a network
192.88.99.0/246to4 relay (deprecated)Formerly anycast for 6to4
192.168.0.0/16Private (RFC 1918)Office and home networks; not routed on the internet
198.18.0.0/15BenchmarkingNetwork equipment testing (RFC 2544)
198.51.100.0/24Documentation (TEST-NET-2)For examples; never used on a network
203.0.113.0/24Documentation (TEST-NET-3)For examples; never used on a network
224.0.0.0/4MulticastOne-to-many traffic, such as IPTV and routing protocols
240.0.0.0/4ReservedFuture use; not usable on most systems

IPv6

Special-purpose ranges
RangeNameWhat it is
::/128UnspecifiedNo address; :: means "any address" in settings
::1/128LoopbackThis computer
::ffff:0:0/96IPv4-mappedAn IPv4 address written as IPv6
64:ff9b::/96NAT64IPv4 addresses reached through a NAT64 gateway
100::/64Discard onlyTraffic sent here is dropped (RFC 6666)
2001:db8::/32DocumentationFor examples; never used on a network
2001::/32TeredoIPv6 tunnelled over IPv4 UDP
2002::/166to4IPv6 tunnelled over IPv4 (largely retired)
3fff::/20DocumentationFor examples (RFC 9637)
fc00::/7Unique local (ULA)Private IPv6, like RFC 1918; usually fd00::/8
fe80::/10Link-localEvery IPv6 interface has one; not routed
ff00::/8MulticastOne-to-many traffic; replaces broadcast
2000::/3Global unicastPublic internet addresses

About this tool

A network is written as an address and a prefix length, such as 192.168.1.0/24: the first 24 bits name the network and the rest number the devices on it. The calculator works out where the network starts and ends, how many devices it holds, its subnet and wildcard masks, and the reverse DNS zone to ask your provider for.

It also splits a network into equal smaller ones (one per VLAN or site), turns a range of addresses into the fewest CIDR blocks for a firewall rule, and lists every IPv4 prefix length and the common IPv6 ones in reference tables.

Common questions

Why are two addresses lost in every IPv4 subnet?

The first address names the network and the last is the broadcast address, so a /24 has 256 addresses but 254 for devices. A /31 (a link between two routers) and a /32 (one host) are the exceptions.

What size of IPv6 network should a LAN use?

Always /64. Devices pick their own address within it (SLAAC), which needs the full 64 bits. A site usually gets a /48 or /56 from its provider, which holds 65,536 or 256 LANs.

What is a wildcard mask?

The subnet mask turned inside out: 255.255.255.0 becomes 0.0.0.255. Cisco access lists and OSPF use it to say which bits must match.

Which ranges can I use inside an office?

IPv4: 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16. IPv6: unique local addresses from fd00::/8, though most networks use the public prefix from their provider.