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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.

Network239.34.0.0/15
Usable hosts131,070
Subnet mask255.254.0.0
Addresses131,072
Network address
239.34.0.0
Broadcast address
239.35.255.255
First usable
239.34.0.1
Last usable
239.35.255.254
Usable hosts
131,070 (131,072 less the network and broadcast addresses)
Subnet mask
255.254.0.0
Wildcard mask
0.1.255.255 (Cisco ACLs, OSPF)
Prefix length
/15
Type
Multicast 224.0.0.0/4
One-to-many traffic, such as IPTV and routing protocols
Old class
D (multicast)
As numbers
Hex EF220000 · Integer 4011982848 to 4012113919
Reverse DNS zones
34.239.in-addr.arpa
35.239.in-addr.arpa
/15 is not on a 8-bit boundary, so it takes 2 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11101111.00100010.00000000.00000000239.34.0.0
Subnet mask11111111.11111110.00000000.00000000255.254.0.0
Network11101111.00100010.00000000.00000000239.34.0.0
Broadcast11101111.00100011.11111111.11111111239.35.255.255
Split into smaller subnets/25
/16 (2)/17 (4)/18 (8)/19 (16)/20 (32)/21 (64)/22 (128)/23 (256)/24 (512)/25 (1,024)/26 (2,048)/27 (4,096)

239.34.0.0/15 makes 1,024 subnets of /25; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1239.34.0.0/25239.34.0.1 to 239.34.0.126239.34.0.127126
2239.34.0.128/25239.34.0.129 to 239.34.0.254239.34.0.255126
3239.34.1.0/25239.34.1.1 to 239.34.1.126239.34.1.127126
4239.34.1.128/25239.34.1.129 to 239.34.1.254239.34.1.255126
5239.34.2.0/25239.34.2.1 to 239.34.2.126239.34.2.127126
6239.34.2.128/25239.34.2.129 to 239.34.2.254239.34.2.255126
7239.34.3.0/25239.34.3.1 to 239.34.3.126239.34.3.127126
8239.34.3.128/25239.34.3.129 to 239.34.3.254239.34.3.255126
9239.34.4.0/25239.34.4.1 to 239.34.4.126239.34.4.127126
10239.34.4.128/25239.34.4.129 to 239.34.4.254239.34.4.255126
11239.34.5.0/25239.34.5.1 to 239.34.5.126239.34.5.127126
12239.34.5.128/25239.34.5.129 to 239.34.5.254239.34.5.255126
13239.34.6.0/25239.34.6.1 to 239.34.6.126239.34.6.127126
14239.34.6.128/25239.34.6.129 to 239.34.6.254239.34.6.255126
15239.34.7.0/25239.34.7.1 to 239.34.7.126239.34.7.127126
16239.34.7.128/25239.34.7.129 to 239.34.7.254239.34.7.255126
17239.34.8.0/25239.34.8.1 to 239.34.8.126239.34.8.127126
18239.34.8.128/25239.34.8.129 to 239.34.8.254239.34.8.255126
19239.34.9.0/25239.34.9.1 to 239.34.9.126239.34.9.127126
20239.34.9.128/25239.34.9.129 to 239.34.9.254239.34.9.255126
21239.34.10.0/25239.34.10.1 to 239.34.10.126239.34.10.127126
22239.34.10.128/25239.34.10.129 to 239.34.10.254239.34.10.255126
23239.34.11.0/25239.34.11.1 to 239.34.11.126239.34.11.127126
24239.34.11.128/25239.34.11.129 to 239.34.11.254239.34.11.255126
25239.34.12.0/25239.34.12.1 to 239.34.12.126239.34.12.127126
26239.34.12.128/25239.34.12.129 to 239.34.12.254239.34.12.255126
27239.34.13.0/25239.34.13.1 to 239.34.13.126239.34.13.127126
28239.34.13.128/25239.34.13.129 to 239.34.13.254239.34.13.255126
29239.34.14.0/25239.34.14.1 to 239.34.14.126239.34.14.127126
30239.34.14.128/25239.34.14.129 to 239.34.14.254239.34.14.255126
31239.34.15.0/25239.34.15.1 to 239.34.15.126239.34.15.127126
32239.34.15.128/25239.34.15.129 to 239.34.15.254239.34.15.255126
33239.34.16.0/25239.34.16.1 to 239.34.16.126239.34.16.127126
34239.34.16.128/25239.34.16.129 to 239.34.16.254239.34.16.255126
35239.34.17.0/25239.34.17.1 to 239.34.17.126239.34.17.127126
36239.34.17.128/25239.34.17.129 to 239.34.17.254239.34.17.255126
37239.34.18.0/25239.34.18.1 to 239.34.18.126239.34.18.127126
38239.34.18.128/25239.34.18.129 to 239.34.18.254239.34.18.255126
39239.34.19.0/25239.34.19.1 to 239.34.19.126239.34.19.127126
40239.34.19.128/25239.34.19.129 to 239.34.19.254239.34.19.255126
41239.34.20.0/25239.34.20.1 to 239.34.20.126239.34.20.127126
42239.34.20.128/25239.34.20.129 to 239.34.20.254239.34.20.255126
43239.34.21.0/25239.34.21.1 to 239.34.21.126239.34.21.127126
44239.34.21.128/25239.34.21.129 to 239.34.21.254239.34.21.255126
45239.34.22.0/25239.34.22.1 to 239.34.22.126239.34.22.127126
46239.34.22.128/25239.34.22.129 to 239.34.22.254239.34.22.255126
47239.34.23.0/25239.34.23.1 to 239.34.23.126239.34.23.127126
48239.34.23.128/25239.34.23.129 to 239.34.23.254239.34.23.255126
49239.34.24.0/25239.34.24.1 to 239.34.24.126239.34.24.127126
50239.34.24.128/25239.34.24.129 to 239.34.24.254239.34.24.255126
51239.34.25.0/25239.34.25.1 to 239.34.25.126239.34.25.127126
52239.34.25.128/25239.34.25.129 to 239.34.25.254239.34.25.255126
53239.34.26.0/25239.34.26.1 to 239.34.26.126239.34.26.127126
54239.34.26.128/25239.34.26.129 to 239.34.26.254239.34.26.255126
55239.34.27.0/25239.34.27.1 to 239.34.27.126239.34.27.127126
56239.34.27.128/25239.34.27.129 to 239.34.27.254239.34.27.255126
57239.34.28.0/25239.34.28.1 to 239.34.28.126239.34.28.127126
58239.34.28.128/25239.34.28.129 to 239.34.28.254239.34.28.255126
59239.34.29.0/25239.34.29.1 to 239.34.29.126239.34.29.127126
60239.34.29.128/25239.34.29.129 to 239.34.29.254239.34.29.255126
61239.34.30.0/25239.34.30.1 to 239.34.30.126239.34.30.127126
62239.34.30.128/25239.34.30.129 to 239.34.30.254239.34.30.255126
63239.34.31.0/25239.34.31.1 to 239.34.31.126239.34.31.127126
64239.34.31.128/25239.34.31.129 to 239.34.31.254239.34.31.255126
65239.34.32.0/25239.34.32.1 to 239.34.32.126239.34.32.127126
66239.34.32.128/25239.34.32.129 to 239.34.32.254239.34.32.255126
67239.34.33.0/25239.34.33.1 to 239.34.33.126239.34.33.127126
68239.34.33.128/25239.34.33.129 to 239.34.33.254239.34.33.255126
69239.34.34.0/25239.34.34.1 to 239.34.34.126239.34.34.127126
70239.34.34.128/25239.34.34.129 to 239.34.34.254239.34.34.255126
71239.34.35.0/25239.34.35.1 to 239.34.35.126239.34.35.127126
72239.34.35.128/25239.34.35.129 to 239.34.35.254239.34.35.255126
73239.34.36.0/25239.34.36.1 to 239.34.36.126239.34.36.127126
74239.34.36.128/25239.34.36.129 to 239.34.36.254239.34.36.255126
75239.34.37.0/25239.34.37.1 to 239.34.37.126239.34.37.127126
76239.34.37.128/25239.34.37.129 to 239.34.37.254239.34.37.255126
77239.34.38.0/25239.34.38.1 to 239.34.38.126239.34.38.127126
78239.34.38.128/25239.34.38.129 to 239.34.38.254239.34.38.255126
79239.34.39.0/25239.34.39.1 to 239.34.39.126239.34.39.127126
80239.34.39.128/25239.34.39.129 to 239.34.39.254239.34.39.255126
81239.34.40.0/25239.34.40.1 to 239.34.40.126239.34.40.127126
82239.34.40.128/25239.34.40.129 to 239.34.40.254239.34.40.255126
83239.34.41.0/25239.34.41.1 to 239.34.41.126239.34.41.127126
84239.34.41.128/25239.34.41.129 to 239.34.41.254239.34.41.255126
85239.34.42.0/25239.34.42.1 to 239.34.42.126239.34.42.127126
86239.34.42.128/25239.34.42.129 to 239.34.42.254239.34.42.255126
87239.34.43.0/25239.34.43.1 to 239.34.43.126239.34.43.127126
88239.34.43.128/25239.34.43.129 to 239.34.43.254239.34.43.255126
89239.34.44.0/25239.34.44.1 to 239.34.44.126239.34.44.127126
90239.34.44.128/25239.34.44.129 to 239.34.44.254239.34.44.255126
91239.34.45.0/25239.34.45.1 to 239.34.45.126239.34.45.127126
92239.34.45.128/25239.34.45.129 to 239.34.45.254239.34.45.255126
93239.34.46.0/25239.34.46.1 to 239.34.46.126239.34.46.127126
94239.34.46.128/25239.34.46.129 to 239.34.46.254239.34.46.255126
95239.34.47.0/25239.34.47.1 to 239.34.47.126239.34.47.127126
96239.34.47.128/25239.34.47.129 to 239.34.47.254239.34.47.255126
97239.34.48.0/25239.34.48.1 to 239.34.48.126239.34.48.127126
98239.34.48.128/25239.34.48.129 to 239.34.48.254239.34.48.255126
99239.34.49.0/25239.34.49.1 to 239.34.49.126239.34.49.127126
100239.34.49.128/25239.34.49.129 to 239.34.49.254239.34.49.255126
101239.34.50.0/25239.34.50.1 to 239.34.50.126239.34.50.127126
102239.34.50.128/25239.34.50.129 to 239.34.50.254239.34.50.255126
103239.34.51.0/25239.34.51.1 to 239.34.51.126239.34.51.127126
104239.34.51.128/25239.34.51.129 to 239.34.51.254239.34.51.255126
105239.34.52.0/25239.34.52.1 to 239.34.52.126239.34.52.127126
106239.34.52.128/25239.34.52.129 to 239.34.52.254239.34.52.255126
107239.34.53.0/25239.34.53.1 to 239.34.53.126239.34.53.127126
108239.34.53.128/25239.34.53.129 to 239.34.53.254239.34.53.255126
109239.34.54.0/25239.34.54.1 to 239.34.54.126239.34.54.127126
110239.34.54.128/25239.34.54.129 to 239.34.54.254239.34.54.255126
111239.34.55.0/25239.34.55.1 to 239.34.55.126239.34.55.127126
112239.34.55.128/25239.34.55.129 to 239.34.55.254239.34.55.255126
113239.34.56.0/25239.34.56.1 to 239.34.56.126239.34.56.127126
114239.34.56.128/25239.34.56.129 to 239.34.56.254239.34.56.255126
115239.34.57.0/25239.34.57.1 to 239.34.57.126239.34.57.127126
116239.34.57.128/25239.34.57.129 to 239.34.57.254239.34.57.255126
117239.34.58.0/25239.34.58.1 to 239.34.58.126239.34.58.127126
118239.34.58.128/25239.34.58.129 to 239.34.58.254239.34.58.255126
119239.34.59.0/25239.34.59.1 to 239.34.59.126239.34.59.127126
120239.34.59.128/25239.34.59.129 to 239.34.59.254239.34.59.255126
121239.34.60.0/25239.34.60.1 to 239.34.60.126239.34.60.127126
122239.34.60.128/25239.34.60.129 to 239.34.60.254239.34.60.255126
123239.34.61.0/25239.34.61.1 to 239.34.61.126239.34.61.127126
124239.34.61.128/25239.34.61.129 to 239.34.61.254239.34.61.255126
125239.34.62.0/25239.34.62.1 to 239.34.62.126239.34.62.127126
126239.34.62.128/25239.34.62.129 to 239.34.62.254239.34.62.255126
127239.34.63.0/25239.34.63.1 to 239.34.63.126239.34.63.127126
128239.34.63.128/25239.34.63.129 to 239.34.63.254239.34.63.255126
129239.34.64.0/25239.34.64.1 to 239.34.64.126239.34.64.127126
130239.34.64.128/25239.34.64.129 to 239.34.64.254239.34.64.255126
131239.34.65.0/25239.34.65.1 to 239.34.65.126239.34.65.127126
132239.34.65.128/25239.34.65.129 to 239.34.65.254239.34.65.255126
133239.34.66.0/25239.34.66.1 to 239.34.66.126239.34.66.127126
134239.34.66.128/25239.34.66.129 to 239.34.66.254239.34.66.255126
135239.34.67.0/25239.34.67.1 to 239.34.67.126239.34.67.127126
136239.34.67.128/25239.34.67.129 to 239.34.67.254239.34.67.255126
137239.34.68.0/25239.34.68.1 to 239.34.68.126239.34.68.127126
138239.34.68.128/25239.34.68.129 to 239.34.68.254239.34.68.255126
139239.34.69.0/25239.34.69.1 to 239.34.69.126239.34.69.127126
140239.34.69.128/25239.34.69.129 to 239.34.69.254239.34.69.255126
141239.34.70.0/25239.34.70.1 to 239.34.70.126239.34.70.127126
142239.34.70.128/25239.34.70.129 to 239.34.70.254239.34.70.255126
143239.34.71.0/25239.34.71.1 to 239.34.71.126239.34.71.127126
144239.34.71.128/25239.34.71.129 to 239.34.71.254239.34.71.255126
145239.34.72.0/25239.34.72.1 to 239.34.72.126239.34.72.127126
146239.34.72.128/25239.34.72.129 to 239.34.72.254239.34.72.255126
147239.34.73.0/25239.34.73.1 to 239.34.73.126239.34.73.127126
148239.34.73.128/25239.34.73.129 to 239.34.73.254239.34.73.255126
149239.34.74.0/25239.34.74.1 to 239.34.74.126239.34.74.127126
150239.34.74.128/25239.34.74.129 to 239.34.74.254239.34.74.255126
151239.34.75.0/25239.34.75.1 to 239.34.75.126239.34.75.127126
152239.34.75.128/25239.34.75.129 to 239.34.75.254239.34.75.255126
153239.34.76.0/25239.34.76.1 to 239.34.76.126239.34.76.127126
154239.34.76.128/25239.34.76.129 to 239.34.76.254239.34.76.255126
155239.34.77.0/25239.34.77.1 to 239.34.77.126239.34.77.127126
156239.34.77.128/25239.34.77.129 to 239.34.77.254239.34.77.255126
157239.34.78.0/25239.34.78.1 to 239.34.78.126239.34.78.127126
158239.34.78.128/25239.34.78.129 to 239.34.78.254239.34.78.255126
159239.34.79.0/25239.34.79.1 to 239.34.79.126239.34.79.127126
160239.34.79.128/25239.34.79.129 to 239.34.79.254239.34.79.255126
161239.34.80.0/25239.34.80.1 to 239.34.80.126239.34.80.127126
162239.34.80.128/25239.34.80.129 to 239.34.80.254239.34.80.255126
163239.34.81.0/25239.34.81.1 to 239.34.81.126239.34.81.127126
164239.34.81.128/25239.34.81.129 to 239.34.81.254239.34.81.255126
165239.34.82.0/25239.34.82.1 to 239.34.82.126239.34.82.127126
166239.34.82.128/25239.34.82.129 to 239.34.82.254239.34.82.255126
167239.34.83.0/25239.34.83.1 to 239.34.83.126239.34.83.127126
168239.34.83.128/25239.34.83.129 to 239.34.83.254239.34.83.255126
169239.34.84.0/25239.34.84.1 to 239.34.84.126239.34.84.127126
170239.34.84.128/25239.34.84.129 to 239.34.84.254239.34.84.255126
171239.34.85.0/25239.34.85.1 to 239.34.85.126239.34.85.127126
172239.34.85.128/25239.34.85.129 to 239.34.85.254239.34.85.255126
173239.34.86.0/25239.34.86.1 to 239.34.86.126239.34.86.127126
174239.34.86.128/25239.34.86.129 to 239.34.86.254239.34.86.255126
175239.34.87.0/25239.34.87.1 to 239.34.87.126239.34.87.127126
176239.34.87.128/25239.34.87.129 to 239.34.87.254239.34.87.255126
177239.34.88.0/25239.34.88.1 to 239.34.88.126239.34.88.127126
178239.34.88.128/25239.34.88.129 to 239.34.88.254239.34.88.255126
179239.34.89.0/25239.34.89.1 to 239.34.89.126239.34.89.127126
180239.34.89.128/25239.34.89.129 to 239.34.89.254239.34.89.255126
181239.34.90.0/25239.34.90.1 to 239.34.90.126239.34.90.127126
182239.34.90.128/25239.34.90.129 to 239.34.90.254239.34.90.255126
183239.34.91.0/25239.34.91.1 to 239.34.91.126239.34.91.127126
184239.34.91.128/25239.34.91.129 to 239.34.91.254239.34.91.255126
185239.34.92.0/25239.34.92.1 to 239.34.92.126239.34.92.127126
186239.34.92.128/25239.34.92.129 to 239.34.92.254239.34.92.255126
187239.34.93.0/25239.34.93.1 to 239.34.93.126239.34.93.127126
188239.34.93.128/25239.34.93.129 to 239.34.93.254239.34.93.255126
189239.34.94.0/25239.34.94.1 to 239.34.94.126239.34.94.127126
190239.34.94.128/25239.34.94.129 to 239.34.94.254239.34.94.255126
191239.34.95.0/25239.34.95.1 to 239.34.95.126239.34.95.127126
192239.34.95.128/25239.34.95.129 to 239.34.95.254239.34.95.255126
193239.34.96.0/25239.34.96.1 to 239.34.96.126239.34.96.127126
194239.34.96.128/25239.34.96.129 to 239.34.96.254239.34.96.255126
195239.34.97.0/25239.34.97.1 to 239.34.97.126239.34.97.127126
196239.34.97.128/25239.34.97.129 to 239.34.97.254239.34.97.255126
197239.34.98.0/25239.34.98.1 to 239.34.98.126239.34.98.127126
198239.34.98.128/25239.34.98.129 to 239.34.98.254239.34.98.255126
199239.34.99.0/25239.34.99.1 to 239.34.99.126239.34.99.127126
200239.34.99.128/25239.34.99.129 to 239.34.99.254239.34.99.255126
201239.34.100.0/25239.34.100.1 to 239.34.100.126239.34.100.127126
202239.34.100.128/25239.34.100.129 to 239.34.100.254239.34.100.255126
203239.34.101.0/25239.34.101.1 to 239.34.101.126239.34.101.127126
204239.34.101.128/25239.34.101.129 to 239.34.101.254239.34.101.255126
205239.34.102.0/25239.34.102.1 to 239.34.102.126239.34.102.127126
206239.34.102.128/25239.34.102.129 to 239.34.102.254239.34.102.255126
207239.34.103.0/25239.34.103.1 to 239.34.103.126239.34.103.127126
208239.34.103.128/25239.34.103.129 to 239.34.103.254239.34.103.255126
209239.34.104.0/25239.34.104.1 to 239.34.104.126239.34.104.127126
210239.34.104.128/25239.34.104.129 to 239.34.104.254239.34.104.255126
211239.34.105.0/25239.34.105.1 to 239.34.105.126239.34.105.127126
212239.34.105.128/25239.34.105.129 to 239.34.105.254239.34.105.255126
213239.34.106.0/25239.34.106.1 to 239.34.106.126239.34.106.127126
214239.34.106.128/25239.34.106.129 to 239.34.106.254239.34.106.255126
215239.34.107.0/25239.34.107.1 to 239.34.107.126239.34.107.127126
216239.34.107.128/25239.34.107.129 to 239.34.107.254239.34.107.255126
217239.34.108.0/25239.34.108.1 to 239.34.108.126239.34.108.127126
218239.34.108.128/25239.34.108.129 to 239.34.108.254239.34.108.255126
219239.34.109.0/25239.34.109.1 to 239.34.109.126239.34.109.127126
220239.34.109.128/25239.34.109.129 to 239.34.109.254239.34.109.255126
221239.34.110.0/25239.34.110.1 to 239.34.110.126239.34.110.127126
222239.34.110.128/25239.34.110.129 to 239.34.110.254239.34.110.255126
223239.34.111.0/25239.34.111.1 to 239.34.111.126239.34.111.127126
224239.34.111.128/25239.34.111.129 to 239.34.111.254239.34.111.255126
225239.34.112.0/25239.34.112.1 to 239.34.112.126239.34.112.127126
226239.34.112.128/25239.34.112.129 to 239.34.112.254239.34.112.255126
227239.34.113.0/25239.34.113.1 to 239.34.113.126239.34.113.127126
228239.34.113.128/25239.34.113.129 to 239.34.113.254239.34.113.255126
229239.34.114.0/25239.34.114.1 to 239.34.114.126239.34.114.127126
230239.34.114.128/25239.34.114.129 to 239.34.114.254239.34.114.255126
231239.34.115.0/25239.34.115.1 to 239.34.115.126239.34.115.127126
232239.34.115.128/25239.34.115.129 to 239.34.115.254239.34.115.255126
233239.34.116.0/25239.34.116.1 to 239.34.116.126239.34.116.127126
234239.34.116.128/25239.34.116.129 to 239.34.116.254239.34.116.255126
235239.34.117.0/25239.34.117.1 to 239.34.117.126239.34.117.127126
236239.34.117.128/25239.34.117.129 to 239.34.117.254239.34.117.255126
237239.34.118.0/25239.34.118.1 to 239.34.118.126239.34.118.127126
238239.34.118.128/25239.34.118.129 to 239.34.118.254239.34.118.255126
239239.34.119.0/25239.34.119.1 to 239.34.119.126239.34.119.127126
240239.34.119.128/25239.34.119.129 to 239.34.119.254239.34.119.255126
241239.34.120.0/25239.34.120.1 to 239.34.120.126239.34.120.127126
242239.34.120.128/25239.34.120.129 to 239.34.120.254239.34.120.255126
243239.34.121.0/25239.34.121.1 to 239.34.121.126239.34.121.127126
244239.34.121.128/25239.34.121.129 to 239.34.121.254239.34.121.255126
245239.34.122.0/25239.34.122.1 to 239.34.122.126239.34.122.127126
246239.34.122.128/25239.34.122.129 to 239.34.122.254239.34.122.255126
247239.34.123.0/25239.34.123.1 to 239.34.123.126239.34.123.127126
248239.34.123.128/25239.34.123.129 to 239.34.123.254239.34.123.255126
249239.34.124.0/25239.34.124.1 to 239.34.124.126239.34.124.127126
250239.34.124.128/25239.34.124.129 to 239.34.124.254239.34.124.255126
251239.34.125.0/25239.34.125.1 to 239.34.125.126239.34.125.127126
252239.34.125.128/25239.34.125.129 to 239.34.125.254239.34.125.255126
253239.34.126.0/25239.34.126.1 to 239.34.126.126239.34.126.127126
254239.34.126.128/25239.34.126.129 to 239.34.126.254239.34.126.255126
255239.34.127.0/25239.34.127.1 to 239.34.127.126239.34.127.127126
256239.34.127.128/25239.34.127.129 to 239.34.127.254239.34.127.255126

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.