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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.

Network155.166.0.0/15
Usable hosts131,070
Subnet mask255.254.0.0
Addresses131,072
Network address
155.166.0.0
Broadcast address
155.167.255.255
First usable
155.166.0.1
Last usable
155.167.255.254
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
Public public
Old class
B (default /16)
As numbers
Hex 9BA60000 · Integer 2611347456 to 2611478527
Reverse DNS zones
166.155.in-addr.arpa
167.155.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
Address10011011.10100110.00000000.00000000155.166.0.0
Subnet mask11111111.11111110.00000000.00000000255.254.0.0
Network10011011.10100110.00000000.00000000155.166.0.0
Broadcast10011011.10100111.11111111.11111111155.167.255.255
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)

155.166.0.0/15 makes 1,024 subnets of /25; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1155.166.0.0/25155.166.0.1 to 155.166.0.126155.166.0.127126
2155.166.0.128/25155.166.0.129 to 155.166.0.254155.166.0.255126
3155.166.1.0/25155.166.1.1 to 155.166.1.126155.166.1.127126
4155.166.1.128/25155.166.1.129 to 155.166.1.254155.166.1.255126
5155.166.2.0/25155.166.2.1 to 155.166.2.126155.166.2.127126
6155.166.2.128/25155.166.2.129 to 155.166.2.254155.166.2.255126
7155.166.3.0/25155.166.3.1 to 155.166.3.126155.166.3.127126
8155.166.3.128/25155.166.3.129 to 155.166.3.254155.166.3.255126
9155.166.4.0/25155.166.4.1 to 155.166.4.126155.166.4.127126
10155.166.4.128/25155.166.4.129 to 155.166.4.254155.166.4.255126
11155.166.5.0/25155.166.5.1 to 155.166.5.126155.166.5.127126
12155.166.5.128/25155.166.5.129 to 155.166.5.254155.166.5.255126
13155.166.6.0/25155.166.6.1 to 155.166.6.126155.166.6.127126
14155.166.6.128/25155.166.6.129 to 155.166.6.254155.166.6.255126
15155.166.7.0/25155.166.7.1 to 155.166.7.126155.166.7.127126
16155.166.7.128/25155.166.7.129 to 155.166.7.254155.166.7.255126
17155.166.8.0/25155.166.8.1 to 155.166.8.126155.166.8.127126
18155.166.8.128/25155.166.8.129 to 155.166.8.254155.166.8.255126
19155.166.9.0/25155.166.9.1 to 155.166.9.126155.166.9.127126
20155.166.9.128/25155.166.9.129 to 155.166.9.254155.166.9.255126
21155.166.10.0/25155.166.10.1 to 155.166.10.126155.166.10.127126
22155.166.10.128/25155.166.10.129 to 155.166.10.254155.166.10.255126
23155.166.11.0/25155.166.11.1 to 155.166.11.126155.166.11.127126
24155.166.11.128/25155.166.11.129 to 155.166.11.254155.166.11.255126
25155.166.12.0/25155.166.12.1 to 155.166.12.126155.166.12.127126
26155.166.12.128/25155.166.12.129 to 155.166.12.254155.166.12.255126
27155.166.13.0/25155.166.13.1 to 155.166.13.126155.166.13.127126
28155.166.13.128/25155.166.13.129 to 155.166.13.254155.166.13.255126
29155.166.14.0/25155.166.14.1 to 155.166.14.126155.166.14.127126
30155.166.14.128/25155.166.14.129 to 155.166.14.254155.166.14.255126
31155.166.15.0/25155.166.15.1 to 155.166.15.126155.166.15.127126
32155.166.15.128/25155.166.15.129 to 155.166.15.254155.166.15.255126
33155.166.16.0/25155.166.16.1 to 155.166.16.126155.166.16.127126
34155.166.16.128/25155.166.16.129 to 155.166.16.254155.166.16.255126
35155.166.17.0/25155.166.17.1 to 155.166.17.126155.166.17.127126
36155.166.17.128/25155.166.17.129 to 155.166.17.254155.166.17.255126
37155.166.18.0/25155.166.18.1 to 155.166.18.126155.166.18.127126
38155.166.18.128/25155.166.18.129 to 155.166.18.254155.166.18.255126
39155.166.19.0/25155.166.19.1 to 155.166.19.126155.166.19.127126
40155.166.19.128/25155.166.19.129 to 155.166.19.254155.166.19.255126
41155.166.20.0/25155.166.20.1 to 155.166.20.126155.166.20.127126
42155.166.20.128/25155.166.20.129 to 155.166.20.254155.166.20.255126
43155.166.21.0/25155.166.21.1 to 155.166.21.126155.166.21.127126
44155.166.21.128/25155.166.21.129 to 155.166.21.254155.166.21.255126
45155.166.22.0/25155.166.22.1 to 155.166.22.126155.166.22.127126
46155.166.22.128/25155.166.22.129 to 155.166.22.254155.166.22.255126
47155.166.23.0/25155.166.23.1 to 155.166.23.126155.166.23.127126
48155.166.23.128/25155.166.23.129 to 155.166.23.254155.166.23.255126
49155.166.24.0/25155.166.24.1 to 155.166.24.126155.166.24.127126
50155.166.24.128/25155.166.24.129 to 155.166.24.254155.166.24.255126
51155.166.25.0/25155.166.25.1 to 155.166.25.126155.166.25.127126
52155.166.25.128/25155.166.25.129 to 155.166.25.254155.166.25.255126
53155.166.26.0/25155.166.26.1 to 155.166.26.126155.166.26.127126
54155.166.26.128/25155.166.26.129 to 155.166.26.254155.166.26.255126
55155.166.27.0/25155.166.27.1 to 155.166.27.126155.166.27.127126
56155.166.27.128/25155.166.27.129 to 155.166.27.254155.166.27.255126
57155.166.28.0/25155.166.28.1 to 155.166.28.126155.166.28.127126
58155.166.28.128/25155.166.28.129 to 155.166.28.254155.166.28.255126
59155.166.29.0/25155.166.29.1 to 155.166.29.126155.166.29.127126
60155.166.29.128/25155.166.29.129 to 155.166.29.254155.166.29.255126
61155.166.30.0/25155.166.30.1 to 155.166.30.126155.166.30.127126
62155.166.30.128/25155.166.30.129 to 155.166.30.254155.166.30.255126
63155.166.31.0/25155.166.31.1 to 155.166.31.126155.166.31.127126
64155.166.31.128/25155.166.31.129 to 155.166.31.254155.166.31.255126
65155.166.32.0/25155.166.32.1 to 155.166.32.126155.166.32.127126
66155.166.32.128/25155.166.32.129 to 155.166.32.254155.166.32.255126
67155.166.33.0/25155.166.33.1 to 155.166.33.126155.166.33.127126
68155.166.33.128/25155.166.33.129 to 155.166.33.254155.166.33.255126
69155.166.34.0/25155.166.34.1 to 155.166.34.126155.166.34.127126
70155.166.34.128/25155.166.34.129 to 155.166.34.254155.166.34.255126
71155.166.35.0/25155.166.35.1 to 155.166.35.126155.166.35.127126
72155.166.35.128/25155.166.35.129 to 155.166.35.254155.166.35.255126
73155.166.36.0/25155.166.36.1 to 155.166.36.126155.166.36.127126
74155.166.36.128/25155.166.36.129 to 155.166.36.254155.166.36.255126
75155.166.37.0/25155.166.37.1 to 155.166.37.126155.166.37.127126
76155.166.37.128/25155.166.37.129 to 155.166.37.254155.166.37.255126
77155.166.38.0/25155.166.38.1 to 155.166.38.126155.166.38.127126
78155.166.38.128/25155.166.38.129 to 155.166.38.254155.166.38.255126
79155.166.39.0/25155.166.39.1 to 155.166.39.126155.166.39.127126
80155.166.39.128/25155.166.39.129 to 155.166.39.254155.166.39.255126
81155.166.40.0/25155.166.40.1 to 155.166.40.126155.166.40.127126
82155.166.40.128/25155.166.40.129 to 155.166.40.254155.166.40.255126
83155.166.41.0/25155.166.41.1 to 155.166.41.126155.166.41.127126
84155.166.41.128/25155.166.41.129 to 155.166.41.254155.166.41.255126
85155.166.42.0/25155.166.42.1 to 155.166.42.126155.166.42.127126
86155.166.42.128/25155.166.42.129 to 155.166.42.254155.166.42.255126
87155.166.43.0/25155.166.43.1 to 155.166.43.126155.166.43.127126
88155.166.43.128/25155.166.43.129 to 155.166.43.254155.166.43.255126
89155.166.44.0/25155.166.44.1 to 155.166.44.126155.166.44.127126
90155.166.44.128/25155.166.44.129 to 155.166.44.254155.166.44.255126
91155.166.45.0/25155.166.45.1 to 155.166.45.126155.166.45.127126
92155.166.45.128/25155.166.45.129 to 155.166.45.254155.166.45.255126
93155.166.46.0/25155.166.46.1 to 155.166.46.126155.166.46.127126
94155.166.46.128/25155.166.46.129 to 155.166.46.254155.166.46.255126
95155.166.47.0/25155.166.47.1 to 155.166.47.126155.166.47.127126
96155.166.47.128/25155.166.47.129 to 155.166.47.254155.166.47.255126
97155.166.48.0/25155.166.48.1 to 155.166.48.126155.166.48.127126
98155.166.48.128/25155.166.48.129 to 155.166.48.254155.166.48.255126
99155.166.49.0/25155.166.49.1 to 155.166.49.126155.166.49.127126
100155.166.49.128/25155.166.49.129 to 155.166.49.254155.166.49.255126
101155.166.50.0/25155.166.50.1 to 155.166.50.126155.166.50.127126
102155.166.50.128/25155.166.50.129 to 155.166.50.254155.166.50.255126
103155.166.51.0/25155.166.51.1 to 155.166.51.126155.166.51.127126
104155.166.51.128/25155.166.51.129 to 155.166.51.254155.166.51.255126
105155.166.52.0/25155.166.52.1 to 155.166.52.126155.166.52.127126
106155.166.52.128/25155.166.52.129 to 155.166.52.254155.166.52.255126
107155.166.53.0/25155.166.53.1 to 155.166.53.126155.166.53.127126
108155.166.53.128/25155.166.53.129 to 155.166.53.254155.166.53.255126
109155.166.54.0/25155.166.54.1 to 155.166.54.126155.166.54.127126
110155.166.54.128/25155.166.54.129 to 155.166.54.254155.166.54.255126
111155.166.55.0/25155.166.55.1 to 155.166.55.126155.166.55.127126
112155.166.55.128/25155.166.55.129 to 155.166.55.254155.166.55.255126
113155.166.56.0/25155.166.56.1 to 155.166.56.126155.166.56.127126
114155.166.56.128/25155.166.56.129 to 155.166.56.254155.166.56.255126
115155.166.57.0/25155.166.57.1 to 155.166.57.126155.166.57.127126
116155.166.57.128/25155.166.57.129 to 155.166.57.254155.166.57.255126
117155.166.58.0/25155.166.58.1 to 155.166.58.126155.166.58.127126
118155.166.58.128/25155.166.58.129 to 155.166.58.254155.166.58.255126
119155.166.59.0/25155.166.59.1 to 155.166.59.126155.166.59.127126
120155.166.59.128/25155.166.59.129 to 155.166.59.254155.166.59.255126
121155.166.60.0/25155.166.60.1 to 155.166.60.126155.166.60.127126
122155.166.60.128/25155.166.60.129 to 155.166.60.254155.166.60.255126
123155.166.61.0/25155.166.61.1 to 155.166.61.126155.166.61.127126
124155.166.61.128/25155.166.61.129 to 155.166.61.254155.166.61.255126
125155.166.62.0/25155.166.62.1 to 155.166.62.126155.166.62.127126
126155.166.62.128/25155.166.62.129 to 155.166.62.254155.166.62.255126
127155.166.63.0/25155.166.63.1 to 155.166.63.126155.166.63.127126
128155.166.63.128/25155.166.63.129 to 155.166.63.254155.166.63.255126
129155.166.64.0/25155.166.64.1 to 155.166.64.126155.166.64.127126
130155.166.64.128/25155.166.64.129 to 155.166.64.254155.166.64.255126
131155.166.65.0/25155.166.65.1 to 155.166.65.126155.166.65.127126
132155.166.65.128/25155.166.65.129 to 155.166.65.254155.166.65.255126
133155.166.66.0/25155.166.66.1 to 155.166.66.126155.166.66.127126
134155.166.66.128/25155.166.66.129 to 155.166.66.254155.166.66.255126
135155.166.67.0/25155.166.67.1 to 155.166.67.126155.166.67.127126
136155.166.67.128/25155.166.67.129 to 155.166.67.254155.166.67.255126
137155.166.68.0/25155.166.68.1 to 155.166.68.126155.166.68.127126
138155.166.68.128/25155.166.68.129 to 155.166.68.254155.166.68.255126
139155.166.69.0/25155.166.69.1 to 155.166.69.126155.166.69.127126
140155.166.69.128/25155.166.69.129 to 155.166.69.254155.166.69.255126
141155.166.70.0/25155.166.70.1 to 155.166.70.126155.166.70.127126
142155.166.70.128/25155.166.70.129 to 155.166.70.254155.166.70.255126
143155.166.71.0/25155.166.71.1 to 155.166.71.126155.166.71.127126
144155.166.71.128/25155.166.71.129 to 155.166.71.254155.166.71.255126
145155.166.72.0/25155.166.72.1 to 155.166.72.126155.166.72.127126
146155.166.72.128/25155.166.72.129 to 155.166.72.254155.166.72.255126
147155.166.73.0/25155.166.73.1 to 155.166.73.126155.166.73.127126
148155.166.73.128/25155.166.73.129 to 155.166.73.254155.166.73.255126
149155.166.74.0/25155.166.74.1 to 155.166.74.126155.166.74.127126
150155.166.74.128/25155.166.74.129 to 155.166.74.254155.166.74.255126
151155.166.75.0/25155.166.75.1 to 155.166.75.126155.166.75.127126
152155.166.75.128/25155.166.75.129 to 155.166.75.254155.166.75.255126
153155.166.76.0/25155.166.76.1 to 155.166.76.126155.166.76.127126
154155.166.76.128/25155.166.76.129 to 155.166.76.254155.166.76.255126
155155.166.77.0/25155.166.77.1 to 155.166.77.126155.166.77.127126
156155.166.77.128/25155.166.77.129 to 155.166.77.254155.166.77.255126
157155.166.78.0/25155.166.78.1 to 155.166.78.126155.166.78.127126
158155.166.78.128/25155.166.78.129 to 155.166.78.254155.166.78.255126
159155.166.79.0/25155.166.79.1 to 155.166.79.126155.166.79.127126
160155.166.79.128/25155.166.79.129 to 155.166.79.254155.166.79.255126
161155.166.80.0/25155.166.80.1 to 155.166.80.126155.166.80.127126
162155.166.80.128/25155.166.80.129 to 155.166.80.254155.166.80.255126
163155.166.81.0/25155.166.81.1 to 155.166.81.126155.166.81.127126
164155.166.81.128/25155.166.81.129 to 155.166.81.254155.166.81.255126
165155.166.82.0/25155.166.82.1 to 155.166.82.126155.166.82.127126
166155.166.82.128/25155.166.82.129 to 155.166.82.254155.166.82.255126
167155.166.83.0/25155.166.83.1 to 155.166.83.126155.166.83.127126
168155.166.83.128/25155.166.83.129 to 155.166.83.254155.166.83.255126
169155.166.84.0/25155.166.84.1 to 155.166.84.126155.166.84.127126
170155.166.84.128/25155.166.84.129 to 155.166.84.254155.166.84.255126
171155.166.85.0/25155.166.85.1 to 155.166.85.126155.166.85.127126
172155.166.85.128/25155.166.85.129 to 155.166.85.254155.166.85.255126
173155.166.86.0/25155.166.86.1 to 155.166.86.126155.166.86.127126
174155.166.86.128/25155.166.86.129 to 155.166.86.254155.166.86.255126
175155.166.87.0/25155.166.87.1 to 155.166.87.126155.166.87.127126
176155.166.87.128/25155.166.87.129 to 155.166.87.254155.166.87.255126
177155.166.88.0/25155.166.88.1 to 155.166.88.126155.166.88.127126
178155.166.88.128/25155.166.88.129 to 155.166.88.254155.166.88.255126
179155.166.89.0/25155.166.89.1 to 155.166.89.126155.166.89.127126
180155.166.89.128/25155.166.89.129 to 155.166.89.254155.166.89.255126
181155.166.90.0/25155.166.90.1 to 155.166.90.126155.166.90.127126
182155.166.90.128/25155.166.90.129 to 155.166.90.254155.166.90.255126
183155.166.91.0/25155.166.91.1 to 155.166.91.126155.166.91.127126
184155.166.91.128/25155.166.91.129 to 155.166.91.254155.166.91.255126
185155.166.92.0/25155.166.92.1 to 155.166.92.126155.166.92.127126
186155.166.92.128/25155.166.92.129 to 155.166.92.254155.166.92.255126
187155.166.93.0/25155.166.93.1 to 155.166.93.126155.166.93.127126
188155.166.93.128/25155.166.93.129 to 155.166.93.254155.166.93.255126
189155.166.94.0/25155.166.94.1 to 155.166.94.126155.166.94.127126
190155.166.94.128/25155.166.94.129 to 155.166.94.254155.166.94.255126
191155.166.95.0/25155.166.95.1 to 155.166.95.126155.166.95.127126
192155.166.95.128/25155.166.95.129 to 155.166.95.254155.166.95.255126
193155.166.96.0/25155.166.96.1 to 155.166.96.126155.166.96.127126
194155.166.96.128/25155.166.96.129 to 155.166.96.254155.166.96.255126
195155.166.97.0/25155.166.97.1 to 155.166.97.126155.166.97.127126
196155.166.97.128/25155.166.97.129 to 155.166.97.254155.166.97.255126
197155.166.98.0/25155.166.98.1 to 155.166.98.126155.166.98.127126
198155.166.98.128/25155.166.98.129 to 155.166.98.254155.166.98.255126
199155.166.99.0/25155.166.99.1 to 155.166.99.126155.166.99.127126
200155.166.99.128/25155.166.99.129 to 155.166.99.254155.166.99.255126
201155.166.100.0/25155.166.100.1 to 155.166.100.126155.166.100.127126
202155.166.100.128/25155.166.100.129 to 155.166.100.254155.166.100.255126
203155.166.101.0/25155.166.101.1 to 155.166.101.126155.166.101.127126
204155.166.101.128/25155.166.101.129 to 155.166.101.254155.166.101.255126
205155.166.102.0/25155.166.102.1 to 155.166.102.126155.166.102.127126
206155.166.102.128/25155.166.102.129 to 155.166.102.254155.166.102.255126
207155.166.103.0/25155.166.103.1 to 155.166.103.126155.166.103.127126
208155.166.103.128/25155.166.103.129 to 155.166.103.254155.166.103.255126
209155.166.104.0/25155.166.104.1 to 155.166.104.126155.166.104.127126
210155.166.104.128/25155.166.104.129 to 155.166.104.254155.166.104.255126
211155.166.105.0/25155.166.105.1 to 155.166.105.126155.166.105.127126
212155.166.105.128/25155.166.105.129 to 155.166.105.254155.166.105.255126
213155.166.106.0/25155.166.106.1 to 155.166.106.126155.166.106.127126
214155.166.106.128/25155.166.106.129 to 155.166.106.254155.166.106.255126
215155.166.107.0/25155.166.107.1 to 155.166.107.126155.166.107.127126
216155.166.107.128/25155.166.107.129 to 155.166.107.254155.166.107.255126
217155.166.108.0/25155.166.108.1 to 155.166.108.126155.166.108.127126
218155.166.108.128/25155.166.108.129 to 155.166.108.254155.166.108.255126
219155.166.109.0/25155.166.109.1 to 155.166.109.126155.166.109.127126
220155.166.109.128/25155.166.109.129 to 155.166.109.254155.166.109.255126
221155.166.110.0/25155.166.110.1 to 155.166.110.126155.166.110.127126
222155.166.110.128/25155.166.110.129 to 155.166.110.254155.166.110.255126
223155.166.111.0/25155.166.111.1 to 155.166.111.126155.166.111.127126
224155.166.111.128/25155.166.111.129 to 155.166.111.254155.166.111.255126
225155.166.112.0/25155.166.112.1 to 155.166.112.126155.166.112.127126
226155.166.112.128/25155.166.112.129 to 155.166.112.254155.166.112.255126
227155.166.113.0/25155.166.113.1 to 155.166.113.126155.166.113.127126
228155.166.113.128/25155.166.113.129 to 155.166.113.254155.166.113.255126
229155.166.114.0/25155.166.114.1 to 155.166.114.126155.166.114.127126
230155.166.114.128/25155.166.114.129 to 155.166.114.254155.166.114.255126
231155.166.115.0/25155.166.115.1 to 155.166.115.126155.166.115.127126
232155.166.115.128/25155.166.115.129 to 155.166.115.254155.166.115.255126
233155.166.116.0/25155.166.116.1 to 155.166.116.126155.166.116.127126
234155.166.116.128/25155.166.116.129 to 155.166.116.254155.166.116.255126
235155.166.117.0/25155.166.117.1 to 155.166.117.126155.166.117.127126
236155.166.117.128/25155.166.117.129 to 155.166.117.254155.166.117.255126
237155.166.118.0/25155.166.118.1 to 155.166.118.126155.166.118.127126
238155.166.118.128/25155.166.118.129 to 155.166.118.254155.166.118.255126
239155.166.119.0/25155.166.119.1 to 155.166.119.126155.166.119.127126
240155.166.119.128/25155.166.119.129 to 155.166.119.254155.166.119.255126
241155.166.120.0/25155.166.120.1 to 155.166.120.126155.166.120.127126
242155.166.120.128/25155.166.120.129 to 155.166.120.254155.166.120.255126
243155.166.121.0/25155.166.121.1 to 155.166.121.126155.166.121.127126
244155.166.121.128/25155.166.121.129 to 155.166.121.254155.166.121.255126
245155.166.122.0/25155.166.122.1 to 155.166.122.126155.166.122.127126
246155.166.122.128/25155.166.122.129 to 155.166.122.254155.166.122.255126
247155.166.123.0/25155.166.123.1 to 155.166.123.126155.166.123.127126
248155.166.123.128/25155.166.123.129 to 155.166.123.254155.166.123.255126
249155.166.124.0/25155.166.124.1 to 155.166.124.126155.166.124.127126
250155.166.124.128/25155.166.124.129 to 155.166.124.254155.166.124.255126
251155.166.125.0/25155.166.125.1 to 155.166.125.126155.166.125.127126
252155.166.125.128/25155.166.125.129 to 155.166.125.254155.166.125.255126
253155.166.126.0/25155.166.126.1 to 155.166.126.126155.166.126.127126
254155.166.126.128/25155.166.126.129 to 155.166.126.254155.166.126.255126
255155.166.127.0/25155.166.127.1 to 155.166.127.126155.166.127.127126
256155.166.127.128/25155.166.127.129 to 155.166.127.254155.166.127.255126

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.