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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.

Network183.72.0.0/13
Usable hosts524,286
Subnet mask255.248.0.0
Addresses524,288
Network address
183.72.0.0
Broadcast address
183.79.255.255
First usable
183.72.0.1
Last usable
183.79.255.254
Usable hosts
524,286 (524,288 less the network and broadcast addresses)
Subnet mask
255.248.0.0
Wildcard mask
0.7.255.255 (Cisco ACLs, OSPF)
Prefix length
/13
Type
Public public
Old class
B (default /16)
As numbers
Hex B7480000 · Integer 3074949120 to 3075473407
Reverse DNS zones
72.183.in-addr.arpa
73.183.in-addr.arpa
74.183.in-addr.arpa
75.183.in-addr.arpa
76.183.in-addr.arpa
77.183.in-addr.arpa
78.183.in-addr.arpa
79.183.in-addr.arpa
/13 is not on a 8-bit boundary, so it takes 8 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10110111.01001000.00000000.00000000183.72.0.0
Subnet mask11111111.11111000.00000000.00000000255.248.0.0
Network10110111.01001000.00000000.00000000183.72.0.0
Broadcast10110111.01001111.11111111.11111111183.79.255.255
Split into smaller subnets/25
/14 (2)/15 (4)/16 (8)/17 (16)/18 (32)/19 (64)/20 (128)/21 (256)/22 (512)/23 (1,024)/24 (2,048)/25 (4,096)

183.72.0.0/13 makes 4,096 subnets of /25; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1183.72.0.0/25183.72.0.1 to 183.72.0.126183.72.0.127126
2183.72.0.128/25183.72.0.129 to 183.72.0.254183.72.0.255126
3183.72.1.0/25183.72.1.1 to 183.72.1.126183.72.1.127126
4183.72.1.128/25183.72.1.129 to 183.72.1.254183.72.1.255126
5183.72.2.0/25183.72.2.1 to 183.72.2.126183.72.2.127126
6183.72.2.128/25183.72.2.129 to 183.72.2.254183.72.2.255126
7183.72.3.0/25183.72.3.1 to 183.72.3.126183.72.3.127126
8183.72.3.128/25183.72.3.129 to 183.72.3.254183.72.3.255126
9183.72.4.0/25183.72.4.1 to 183.72.4.126183.72.4.127126
10183.72.4.128/25183.72.4.129 to 183.72.4.254183.72.4.255126
11183.72.5.0/25183.72.5.1 to 183.72.5.126183.72.5.127126
12183.72.5.128/25183.72.5.129 to 183.72.5.254183.72.5.255126
13183.72.6.0/25183.72.6.1 to 183.72.6.126183.72.6.127126
14183.72.6.128/25183.72.6.129 to 183.72.6.254183.72.6.255126
15183.72.7.0/25183.72.7.1 to 183.72.7.126183.72.7.127126
16183.72.7.128/25183.72.7.129 to 183.72.7.254183.72.7.255126
17183.72.8.0/25183.72.8.1 to 183.72.8.126183.72.8.127126
18183.72.8.128/25183.72.8.129 to 183.72.8.254183.72.8.255126
19183.72.9.0/25183.72.9.1 to 183.72.9.126183.72.9.127126
20183.72.9.128/25183.72.9.129 to 183.72.9.254183.72.9.255126
21183.72.10.0/25183.72.10.1 to 183.72.10.126183.72.10.127126
22183.72.10.128/25183.72.10.129 to 183.72.10.254183.72.10.255126
23183.72.11.0/25183.72.11.1 to 183.72.11.126183.72.11.127126
24183.72.11.128/25183.72.11.129 to 183.72.11.254183.72.11.255126
25183.72.12.0/25183.72.12.1 to 183.72.12.126183.72.12.127126
26183.72.12.128/25183.72.12.129 to 183.72.12.254183.72.12.255126
27183.72.13.0/25183.72.13.1 to 183.72.13.126183.72.13.127126
28183.72.13.128/25183.72.13.129 to 183.72.13.254183.72.13.255126
29183.72.14.0/25183.72.14.1 to 183.72.14.126183.72.14.127126
30183.72.14.128/25183.72.14.129 to 183.72.14.254183.72.14.255126
31183.72.15.0/25183.72.15.1 to 183.72.15.126183.72.15.127126
32183.72.15.128/25183.72.15.129 to 183.72.15.254183.72.15.255126
33183.72.16.0/25183.72.16.1 to 183.72.16.126183.72.16.127126
34183.72.16.128/25183.72.16.129 to 183.72.16.254183.72.16.255126
35183.72.17.0/25183.72.17.1 to 183.72.17.126183.72.17.127126
36183.72.17.128/25183.72.17.129 to 183.72.17.254183.72.17.255126
37183.72.18.0/25183.72.18.1 to 183.72.18.126183.72.18.127126
38183.72.18.128/25183.72.18.129 to 183.72.18.254183.72.18.255126
39183.72.19.0/25183.72.19.1 to 183.72.19.126183.72.19.127126
40183.72.19.128/25183.72.19.129 to 183.72.19.254183.72.19.255126
41183.72.20.0/25183.72.20.1 to 183.72.20.126183.72.20.127126
42183.72.20.128/25183.72.20.129 to 183.72.20.254183.72.20.255126
43183.72.21.0/25183.72.21.1 to 183.72.21.126183.72.21.127126
44183.72.21.128/25183.72.21.129 to 183.72.21.254183.72.21.255126
45183.72.22.0/25183.72.22.1 to 183.72.22.126183.72.22.127126
46183.72.22.128/25183.72.22.129 to 183.72.22.254183.72.22.255126
47183.72.23.0/25183.72.23.1 to 183.72.23.126183.72.23.127126
48183.72.23.128/25183.72.23.129 to 183.72.23.254183.72.23.255126
49183.72.24.0/25183.72.24.1 to 183.72.24.126183.72.24.127126
50183.72.24.128/25183.72.24.129 to 183.72.24.254183.72.24.255126
51183.72.25.0/25183.72.25.1 to 183.72.25.126183.72.25.127126
52183.72.25.128/25183.72.25.129 to 183.72.25.254183.72.25.255126
53183.72.26.0/25183.72.26.1 to 183.72.26.126183.72.26.127126
54183.72.26.128/25183.72.26.129 to 183.72.26.254183.72.26.255126
55183.72.27.0/25183.72.27.1 to 183.72.27.126183.72.27.127126
56183.72.27.128/25183.72.27.129 to 183.72.27.254183.72.27.255126
57183.72.28.0/25183.72.28.1 to 183.72.28.126183.72.28.127126
58183.72.28.128/25183.72.28.129 to 183.72.28.254183.72.28.255126
59183.72.29.0/25183.72.29.1 to 183.72.29.126183.72.29.127126
60183.72.29.128/25183.72.29.129 to 183.72.29.254183.72.29.255126
61183.72.30.0/25183.72.30.1 to 183.72.30.126183.72.30.127126
62183.72.30.128/25183.72.30.129 to 183.72.30.254183.72.30.255126
63183.72.31.0/25183.72.31.1 to 183.72.31.126183.72.31.127126
64183.72.31.128/25183.72.31.129 to 183.72.31.254183.72.31.255126
65183.72.32.0/25183.72.32.1 to 183.72.32.126183.72.32.127126
66183.72.32.128/25183.72.32.129 to 183.72.32.254183.72.32.255126
67183.72.33.0/25183.72.33.1 to 183.72.33.126183.72.33.127126
68183.72.33.128/25183.72.33.129 to 183.72.33.254183.72.33.255126
69183.72.34.0/25183.72.34.1 to 183.72.34.126183.72.34.127126
70183.72.34.128/25183.72.34.129 to 183.72.34.254183.72.34.255126
71183.72.35.0/25183.72.35.1 to 183.72.35.126183.72.35.127126
72183.72.35.128/25183.72.35.129 to 183.72.35.254183.72.35.255126
73183.72.36.0/25183.72.36.1 to 183.72.36.126183.72.36.127126
74183.72.36.128/25183.72.36.129 to 183.72.36.254183.72.36.255126
75183.72.37.0/25183.72.37.1 to 183.72.37.126183.72.37.127126
76183.72.37.128/25183.72.37.129 to 183.72.37.254183.72.37.255126
77183.72.38.0/25183.72.38.1 to 183.72.38.126183.72.38.127126
78183.72.38.128/25183.72.38.129 to 183.72.38.254183.72.38.255126
79183.72.39.0/25183.72.39.1 to 183.72.39.126183.72.39.127126
80183.72.39.128/25183.72.39.129 to 183.72.39.254183.72.39.255126
81183.72.40.0/25183.72.40.1 to 183.72.40.126183.72.40.127126
82183.72.40.128/25183.72.40.129 to 183.72.40.254183.72.40.255126
83183.72.41.0/25183.72.41.1 to 183.72.41.126183.72.41.127126
84183.72.41.128/25183.72.41.129 to 183.72.41.254183.72.41.255126
85183.72.42.0/25183.72.42.1 to 183.72.42.126183.72.42.127126
86183.72.42.128/25183.72.42.129 to 183.72.42.254183.72.42.255126
87183.72.43.0/25183.72.43.1 to 183.72.43.126183.72.43.127126
88183.72.43.128/25183.72.43.129 to 183.72.43.254183.72.43.255126
89183.72.44.0/25183.72.44.1 to 183.72.44.126183.72.44.127126
90183.72.44.128/25183.72.44.129 to 183.72.44.254183.72.44.255126
91183.72.45.0/25183.72.45.1 to 183.72.45.126183.72.45.127126
92183.72.45.128/25183.72.45.129 to 183.72.45.254183.72.45.255126
93183.72.46.0/25183.72.46.1 to 183.72.46.126183.72.46.127126
94183.72.46.128/25183.72.46.129 to 183.72.46.254183.72.46.255126
95183.72.47.0/25183.72.47.1 to 183.72.47.126183.72.47.127126
96183.72.47.128/25183.72.47.129 to 183.72.47.254183.72.47.255126
97183.72.48.0/25183.72.48.1 to 183.72.48.126183.72.48.127126
98183.72.48.128/25183.72.48.129 to 183.72.48.254183.72.48.255126
99183.72.49.0/25183.72.49.1 to 183.72.49.126183.72.49.127126
100183.72.49.128/25183.72.49.129 to 183.72.49.254183.72.49.255126
101183.72.50.0/25183.72.50.1 to 183.72.50.126183.72.50.127126
102183.72.50.128/25183.72.50.129 to 183.72.50.254183.72.50.255126
103183.72.51.0/25183.72.51.1 to 183.72.51.126183.72.51.127126
104183.72.51.128/25183.72.51.129 to 183.72.51.254183.72.51.255126
105183.72.52.0/25183.72.52.1 to 183.72.52.126183.72.52.127126
106183.72.52.128/25183.72.52.129 to 183.72.52.254183.72.52.255126
107183.72.53.0/25183.72.53.1 to 183.72.53.126183.72.53.127126
108183.72.53.128/25183.72.53.129 to 183.72.53.254183.72.53.255126
109183.72.54.0/25183.72.54.1 to 183.72.54.126183.72.54.127126
110183.72.54.128/25183.72.54.129 to 183.72.54.254183.72.54.255126
111183.72.55.0/25183.72.55.1 to 183.72.55.126183.72.55.127126
112183.72.55.128/25183.72.55.129 to 183.72.55.254183.72.55.255126
113183.72.56.0/25183.72.56.1 to 183.72.56.126183.72.56.127126
114183.72.56.128/25183.72.56.129 to 183.72.56.254183.72.56.255126
115183.72.57.0/25183.72.57.1 to 183.72.57.126183.72.57.127126
116183.72.57.128/25183.72.57.129 to 183.72.57.254183.72.57.255126
117183.72.58.0/25183.72.58.1 to 183.72.58.126183.72.58.127126
118183.72.58.128/25183.72.58.129 to 183.72.58.254183.72.58.255126
119183.72.59.0/25183.72.59.1 to 183.72.59.126183.72.59.127126
120183.72.59.128/25183.72.59.129 to 183.72.59.254183.72.59.255126
121183.72.60.0/25183.72.60.1 to 183.72.60.126183.72.60.127126
122183.72.60.128/25183.72.60.129 to 183.72.60.254183.72.60.255126
123183.72.61.0/25183.72.61.1 to 183.72.61.126183.72.61.127126
124183.72.61.128/25183.72.61.129 to 183.72.61.254183.72.61.255126
125183.72.62.0/25183.72.62.1 to 183.72.62.126183.72.62.127126
126183.72.62.128/25183.72.62.129 to 183.72.62.254183.72.62.255126
127183.72.63.0/25183.72.63.1 to 183.72.63.126183.72.63.127126
128183.72.63.128/25183.72.63.129 to 183.72.63.254183.72.63.255126
129183.72.64.0/25183.72.64.1 to 183.72.64.126183.72.64.127126
130183.72.64.128/25183.72.64.129 to 183.72.64.254183.72.64.255126
131183.72.65.0/25183.72.65.1 to 183.72.65.126183.72.65.127126
132183.72.65.128/25183.72.65.129 to 183.72.65.254183.72.65.255126
133183.72.66.0/25183.72.66.1 to 183.72.66.126183.72.66.127126
134183.72.66.128/25183.72.66.129 to 183.72.66.254183.72.66.255126
135183.72.67.0/25183.72.67.1 to 183.72.67.126183.72.67.127126
136183.72.67.128/25183.72.67.129 to 183.72.67.254183.72.67.255126
137183.72.68.0/25183.72.68.1 to 183.72.68.126183.72.68.127126
138183.72.68.128/25183.72.68.129 to 183.72.68.254183.72.68.255126
139183.72.69.0/25183.72.69.1 to 183.72.69.126183.72.69.127126
140183.72.69.128/25183.72.69.129 to 183.72.69.254183.72.69.255126
141183.72.70.0/25183.72.70.1 to 183.72.70.126183.72.70.127126
142183.72.70.128/25183.72.70.129 to 183.72.70.254183.72.70.255126
143183.72.71.0/25183.72.71.1 to 183.72.71.126183.72.71.127126
144183.72.71.128/25183.72.71.129 to 183.72.71.254183.72.71.255126
145183.72.72.0/25183.72.72.1 to 183.72.72.126183.72.72.127126
146183.72.72.128/25183.72.72.129 to 183.72.72.254183.72.72.255126
147183.72.73.0/25183.72.73.1 to 183.72.73.126183.72.73.127126
148183.72.73.128/25183.72.73.129 to 183.72.73.254183.72.73.255126
149183.72.74.0/25183.72.74.1 to 183.72.74.126183.72.74.127126
150183.72.74.128/25183.72.74.129 to 183.72.74.254183.72.74.255126
151183.72.75.0/25183.72.75.1 to 183.72.75.126183.72.75.127126
152183.72.75.128/25183.72.75.129 to 183.72.75.254183.72.75.255126
153183.72.76.0/25183.72.76.1 to 183.72.76.126183.72.76.127126
154183.72.76.128/25183.72.76.129 to 183.72.76.254183.72.76.255126
155183.72.77.0/25183.72.77.1 to 183.72.77.126183.72.77.127126
156183.72.77.128/25183.72.77.129 to 183.72.77.254183.72.77.255126
157183.72.78.0/25183.72.78.1 to 183.72.78.126183.72.78.127126
158183.72.78.128/25183.72.78.129 to 183.72.78.254183.72.78.255126
159183.72.79.0/25183.72.79.1 to 183.72.79.126183.72.79.127126
160183.72.79.128/25183.72.79.129 to 183.72.79.254183.72.79.255126
161183.72.80.0/25183.72.80.1 to 183.72.80.126183.72.80.127126
162183.72.80.128/25183.72.80.129 to 183.72.80.254183.72.80.255126
163183.72.81.0/25183.72.81.1 to 183.72.81.126183.72.81.127126
164183.72.81.128/25183.72.81.129 to 183.72.81.254183.72.81.255126
165183.72.82.0/25183.72.82.1 to 183.72.82.126183.72.82.127126
166183.72.82.128/25183.72.82.129 to 183.72.82.254183.72.82.255126
167183.72.83.0/25183.72.83.1 to 183.72.83.126183.72.83.127126
168183.72.83.128/25183.72.83.129 to 183.72.83.254183.72.83.255126
169183.72.84.0/25183.72.84.1 to 183.72.84.126183.72.84.127126
170183.72.84.128/25183.72.84.129 to 183.72.84.254183.72.84.255126
171183.72.85.0/25183.72.85.1 to 183.72.85.126183.72.85.127126
172183.72.85.128/25183.72.85.129 to 183.72.85.254183.72.85.255126
173183.72.86.0/25183.72.86.1 to 183.72.86.126183.72.86.127126
174183.72.86.128/25183.72.86.129 to 183.72.86.254183.72.86.255126
175183.72.87.0/25183.72.87.1 to 183.72.87.126183.72.87.127126
176183.72.87.128/25183.72.87.129 to 183.72.87.254183.72.87.255126
177183.72.88.0/25183.72.88.1 to 183.72.88.126183.72.88.127126
178183.72.88.128/25183.72.88.129 to 183.72.88.254183.72.88.255126
179183.72.89.0/25183.72.89.1 to 183.72.89.126183.72.89.127126
180183.72.89.128/25183.72.89.129 to 183.72.89.254183.72.89.255126
181183.72.90.0/25183.72.90.1 to 183.72.90.126183.72.90.127126
182183.72.90.128/25183.72.90.129 to 183.72.90.254183.72.90.255126
183183.72.91.0/25183.72.91.1 to 183.72.91.126183.72.91.127126
184183.72.91.128/25183.72.91.129 to 183.72.91.254183.72.91.255126
185183.72.92.0/25183.72.92.1 to 183.72.92.126183.72.92.127126
186183.72.92.128/25183.72.92.129 to 183.72.92.254183.72.92.255126
187183.72.93.0/25183.72.93.1 to 183.72.93.126183.72.93.127126
188183.72.93.128/25183.72.93.129 to 183.72.93.254183.72.93.255126
189183.72.94.0/25183.72.94.1 to 183.72.94.126183.72.94.127126
190183.72.94.128/25183.72.94.129 to 183.72.94.254183.72.94.255126
191183.72.95.0/25183.72.95.1 to 183.72.95.126183.72.95.127126
192183.72.95.128/25183.72.95.129 to 183.72.95.254183.72.95.255126
193183.72.96.0/25183.72.96.1 to 183.72.96.126183.72.96.127126
194183.72.96.128/25183.72.96.129 to 183.72.96.254183.72.96.255126
195183.72.97.0/25183.72.97.1 to 183.72.97.126183.72.97.127126
196183.72.97.128/25183.72.97.129 to 183.72.97.254183.72.97.255126
197183.72.98.0/25183.72.98.1 to 183.72.98.126183.72.98.127126
198183.72.98.128/25183.72.98.129 to 183.72.98.254183.72.98.255126
199183.72.99.0/25183.72.99.1 to 183.72.99.126183.72.99.127126
200183.72.99.128/25183.72.99.129 to 183.72.99.254183.72.99.255126
201183.72.100.0/25183.72.100.1 to 183.72.100.126183.72.100.127126
202183.72.100.128/25183.72.100.129 to 183.72.100.254183.72.100.255126
203183.72.101.0/25183.72.101.1 to 183.72.101.126183.72.101.127126
204183.72.101.128/25183.72.101.129 to 183.72.101.254183.72.101.255126
205183.72.102.0/25183.72.102.1 to 183.72.102.126183.72.102.127126
206183.72.102.128/25183.72.102.129 to 183.72.102.254183.72.102.255126
207183.72.103.0/25183.72.103.1 to 183.72.103.126183.72.103.127126
208183.72.103.128/25183.72.103.129 to 183.72.103.254183.72.103.255126
209183.72.104.0/25183.72.104.1 to 183.72.104.126183.72.104.127126
210183.72.104.128/25183.72.104.129 to 183.72.104.254183.72.104.255126
211183.72.105.0/25183.72.105.1 to 183.72.105.126183.72.105.127126
212183.72.105.128/25183.72.105.129 to 183.72.105.254183.72.105.255126
213183.72.106.0/25183.72.106.1 to 183.72.106.126183.72.106.127126
214183.72.106.128/25183.72.106.129 to 183.72.106.254183.72.106.255126
215183.72.107.0/25183.72.107.1 to 183.72.107.126183.72.107.127126
216183.72.107.128/25183.72.107.129 to 183.72.107.254183.72.107.255126
217183.72.108.0/25183.72.108.1 to 183.72.108.126183.72.108.127126
218183.72.108.128/25183.72.108.129 to 183.72.108.254183.72.108.255126
219183.72.109.0/25183.72.109.1 to 183.72.109.126183.72.109.127126
220183.72.109.128/25183.72.109.129 to 183.72.109.254183.72.109.255126
221183.72.110.0/25183.72.110.1 to 183.72.110.126183.72.110.127126
222183.72.110.128/25183.72.110.129 to 183.72.110.254183.72.110.255126
223183.72.111.0/25183.72.111.1 to 183.72.111.126183.72.111.127126
224183.72.111.128/25183.72.111.129 to 183.72.111.254183.72.111.255126
225183.72.112.0/25183.72.112.1 to 183.72.112.126183.72.112.127126
226183.72.112.128/25183.72.112.129 to 183.72.112.254183.72.112.255126
227183.72.113.0/25183.72.113.1 to 183.72.113.126183.72.113.127126
228183.72.113.128/25183.72.113.129 to 183.72.113.254183.72.113.255126
229183.72.114.0/25183.72.114.1 to 183.72.114.126183.72.114.127126
230183.72.114.128/25183.72.114.129 to 183.72.114.254183.72.114.255126
231183.72.115.0/25183.72.115.1 to 183.72.115.126183.72.115.127126
232183.72.115.128/25183.72.115.129 to 183.72.115.254183.72.115.255126
233183.72.116.0/25183.72.116.1 to 183.72.116.126183.72.116.127126
234183.72.116.128/25183.72.116.129 to 183.72.116.254183.72.116.255126
235183.72.117.0/25183.72.117.1 to 183.72.117.126183.72.117.127126
236183.72.117.128/25183.72.117.129 to 183.72.117.254183.72.117.255126
237183.72.118.0/25183.72.118.1 to 183.72.118.126183.72.118.127126
238183.72.118.128/25183.72.118.129 to 183.72.118.254183.72.118.255126
239183.72.119.0/25183.72.119.1 to 183.72.119.126183.72.119.127126
240183.72.119.128/25183.72.119.129 to 183.72.119.254183.72.119.255126
241183.72.120.0/25183.72.120.1 to 183.72.120.126183.72.120.127126
242183.72.120.128/25183.72.120.129 to 183.72.120.254183.72.120.255126
243183.72.121.0/25183.72.121.1 to 183.72.121.126183.72.121.127126
244183.72.121.128/25183.72.121.129 to 183.72.121.254183.72.121.255126
245183.72.122.0/25183.72.122.1 to 183.72.122.126183.72.122.127126
246183.72.122.128/25183.72.122.129 to 183.72.122.254183.72.122.255126
247183.72.123.0/25183.72.123.1 to 183.72.123.126183.72.123.127126
248183.72.123.128/25183.72.123.129 to 183.72.123.254183.72.123.255126
249183.72.124.0/25183.72.124.1 to 183.72.124.126183.72.124.127126
250183.72.124.128/25183.72.124.129 to 183.72.124.254183.72.124.255126
251183.72.125.0/25183.72.125.1 to 183.72.125.126183.72.125.127126
252183.72.125.128/25183.72.125.129 to 183.72.125.254183.72.125.255126
253183.72.126.0/25183.72.126.1 to 183.72.126.126183.72.126.127126
254183.72.126.128/25183.72.126.129 to 183.72.126.254183.72.126.255126
255183.72.127.0/25183.72.127.1 to 183.72.127.126183.72.127.127126
256183.72.127.128/25183.72.127.129 to 183.72.127.254183.72.127.255126

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.