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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.

Network155.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
155.0.0.0
Broadcast address
155.255.255.255
First usable
155.0.0.1
Last usable
155.255.255.254
Usable hosts
16,777,214 (16,777,216 less the network and broadcast addresses)
Subnet mask
255.0.0.0
Wildcard mask
0.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/8
Type
Public public
Old class
B (default /16)
As numbers
Hex 9B000000 · Integer 2600468480 to 2617245695
Reverse DNS zone
155.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10011011..00000000.00000000.00000000155.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network10011011..00000000.00000000.00000000155.0.0.0
Broadcast10011011..11111111.11111111.11111111155.255.255.255
Split into smaller subnets/17
/9 (2)/10 (4)/11 (8)/12 (16)/13 (32)/14 (64)/15 (128)/16 (256)/17 (512)/18 (1,024)/19 (2,048)/20 (4,096)

155.0.0.0/8 makes 512 subnets of /17; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1155.0.0.0/17155.0.0.1 to 155.0.127.254155.0.127.25532,766
2155.0.128.0/17155.0.128.1 to 155.0.255.254155.0.255.25532,766
3155.1.0.0/17155.1.0.1 to 155.1.127.254155.1.127.25532,766
4155.1.128.0/17155.1.128.1 to 155.1.255.254155.1.255.25532,766
5155.2.0.0/17155.2.0.1 to 155.2.127.254155.2.127.25532,766
6155.2.128.0/17155.2.128.1 to 155.2.255.254155.2.255.25532,766
7155.3.0.0/17155.3.0.1 to 155.3.127.254155.3.127.25532,766
8155.3.128.0/17155.3.128.1 to 155.3.255.254155.3.255.25532,766
9155.4.0.0/17155.4.0.1 to 155.4.127.254155.4.127.25532,766
10155.4.128.0/17155.4.128.1 to 155.4.255.254155.4.255.25532,766
11155.5.0.0/17155.5.0.1 to 155.5.127.254155.5.127.25532,766
12155.5.128.0/17155.5.128.1 to 155.5.255.254155.5.255.25532,766
13155.6.0.0/17155.6.0.1 to 155.6.127.254155.6.127.25532,766
14155.6.128.0/17155.6.128.1 to 155.6.255.254155.6.255.25532,766
15155.7.0.0/17155.7.0.1 to 155.7.127.254155.7.127.25532,766
16155.7.128.0/17155.7.128.1 to 155.7.255.254155.7.255.25532,766
17155.8.0.0/17155.8.0.1 to 155.8.127.254155.8.127.25532,766
18155.8.128.0/17155.8.128.1 to 155.8.255.254155.8.255.25532,766
19155.9.0.0/17155.9.0.1 to 155.9.127.254155.9.127.25532,766
20155.9.128.0/17155.9.128.1 to 155.9.255.254155.9.255.25532,766
21155.10.0.0/17155.10.0.1 to 155.10.127.254155.10.127.25532,766
22155.10.128.0/17155.10.128.1 to 155.10.255.254155.10.255.25532,766
23155.11.0.0/17155.11.0.1 to 155.11.127.254155.11.127.25532,766
24155.11.128.0/17155.11.128.1 to 155.11.255.254155.11.255.25532,766
25155.12.0.0/17155.12.0.1 to 155.12.127.254155.12.127.25532,766
26155.12.128.0/17155.12.128.1 to 155.12.255.254155.12.255.25532,766
27155.13.0.0/17155.13.0.1 to 155.13.127.254155.13.127.25532,766
28155.13.128.0/17155.13.128.1 to 155.13.255.254155.13.255.25532,766
29155.14.0.0/17155.14.0.1 to 155.14.127.254155.14.127.25532,766
30155.14.128.0/17155.14.128.1 to 155.14.255.254155.14.255.25532,766
31155.15.0.0/17155.15.0.1 to 155.15.127.254155.15.127.25532,766
32155.15.128.0/17155.15.128.1 to 155.15.255.254155.15.255.25532,766
33155.16.0.0/17155.16.0.1 to 155.16.127.254155.16.127.25532,766
34155.16.128.0/17155.16.128.1 to 155.16.255.254155.16.255.25532,766
35155.17.0.0/17155.17.0.1 to 155.17.127.254155.17.127.25532,766
36155.17.128.0/17155.17.128.1 to 155.17.255.254155.17.255.25532,766
37155.18.0.0/17155.18.0.1 to 155.18.127.254155.18.127.25532,766
38155.18.128.0/17155.18.128.1 to 155.18.255.254155.18.255.25532,766
39155.19.0.0/17155.19.0.1 to 155.19.127.254155.19.127.25532,766
40155.19.128.0/17155.19.128.1 to 155.19.255.254155.19.255.25532,766
41155.20.0.0/17155.20.0.1 to 155.20.127.254155.20.127.25532,766
42155.20.128.0/17155.20.128.1 to 155.20.255.254155.20.255.25532,766
43155.21.0.0/17155.21.0.1 to 155.21.127.254155.21.127.25532,766
44155.21.128.0/17155.21.128.1 to 155.21.255.254155.21.255.25532,766
45155.22.0.0/17155.22.0.1 to 155.22.127.254155.22.127.25532,766
46155.22.128.0/17155.22.128.1 to 155.22.255.254155.22.255.25532,766
47155.23.0.0/17155.23.0.1 to 155.23.127.254155.23.127.25532,766
48155.23.128.0/17155.23.128.1 to 155.23.255.254155.23.255.25532,766
49155.24.0.0/17155.24.0.1 to 155.24.127.254155.24.127.25532,766
50155.24.128.0/17155.24.128.1 to 155.24.255.254155.24.255.25532,766
51155.25.0.0/17155.25.0.1 to 155.25.127.254155.25.127.25532,766
52155.25.128.0/17155.25.128.1 to 155.25.255.254155.25.255.25532,766
53155.26.0.0/17155.26.0.1 to 155.26.127.254155.26.127.25532,766
54155.26.128.0/17155.26.128.1 to 155.26.255.254155.26.255.25532,766
55155.27.0.0/17155.27.0.1 to 155.27.127.254155.27.127.25532,766
56155.27.128.0/17155.27.128.1 to 155.27.255.254155.27.255.25532,766
57155.28.0.0/17155.28.0.1 to 155.28.127.254155.28.127.25532,766
58155.28.128.0/17155.28.128.1 to 155.28.255.254155.28.255.25532,766
59155.29.0.0/17155.29.0.1 to 155.29.127.254155.29.127.25532,766
60155.29.128.0/17155.29.128.1 to 155.29.255.254155.29.255.25532,766
61155.30.0.0/17155.30.0.1 to 155.30.127.254155.30.127.25532,766
62155.30.128.0/17155.30.128.1 to 155.30.255.254155.30.255.25532,766
63155.31.0.0/17155.31.0.1 to 155.31.127.254155.31.127.25532,766
64155.31.128.0/17155.31.128.1 to 155.31.255.254155.31.255.25532,766
65155.32.0.0/17155.32.0.1 to 155.32.127.254155.32.127.25532,766
66155.32.128.0/17155.32.128.1 to 155.32.255.254155.32.255.25532,766
67155.33.0.0/17155.33.0.1 to 155.33.127.254155.33.127.25532,766
68155.33.128.0/17155.33.128.1 to 155.33.255.254155.33.255.25532,766
69155.34.0.0/17155.34.0.1 to 155.34.127.254155.34.127.25532,766
70155.34.128.0/17155.34.128.1 to 155.34.255.254155.34.255.25532,766
71155.35.0.0/17155.35.0.1 to 155.35.127.254155.35.127.25532,766
72155.35.128.0/17155.35.128.1 to 155.35.255.254155.35.255.25532,766
73155.36.0.0/17155.36.0.1 to 155.36.127.254155.36.127.25532,766
74155.36.128.0/17155.36.128.1 to 155.36.255.254155.36.255.25532,766
75155.37.0.0/17155.37.0.1 to 155.37.127.254155.37.127.25532,766
76155.37.128.0/17155.37.128.1 to 155.37.255.254155.37.255.25532,766
77155.38.0.0/17155.38.0.1 to 155.38.127.254155.38.127.25532,766
78155.38.128.0/17155.38.128.1 to 155.38.255.254155.38.255.25532,766
79155.39.0.0/17155.39.0.1 to 155.39.127.254155.39.127.25532,766
80155.39.128.0/17155.39.128.1 to 155.39.255.254155.39.255.25532,766
81155.40.0.0/17155.40.0.1 to 155.40.127.254155.40.127.25532,766
82155.40.128.0/17155.40.128.1 to 155.40.255.254155.40.255.25532,766
83155.41.0.0/17155.41.0.1 to 155.41.127.254155.41.127.25532,766
84155.41.128.0/17155.41.128.1 to 155.41.255.254155.41.255.25532,766
85155.42.0.0/17155.42.0.1 to 155.42.127.254155.42.127.25532,766
86155.42.128.0/17155.42.128.1 to 155.42.255.254155.42.255.25532,766
87155.43.0.0/17155.43.0.1 to 155.43.127.254155.43.127.25532,766
88155.43.128.0/17155.43.128.1 to 155.43.255.254155.43.255.25532,766
89155.44.0.0/17155.44.0.1 to 155.44.127.254155.44.127.25532,766
90155.44.128.0/17155.44.128.1 to 155.44.255.254155.44.255.25532,766
91155.45.0.0/17155.45.0.1 to 155.45.127.254155.45.127.25532,766
92155.45.128.0/17155.45.128.1 to 155.45.255.254155.45.255.25532,766
93155.46.0.0/17155.46.0.1 to 155.46.127.254155.46.127.25532,766
94155.46.128.0/17155.46.128.1 to 155.46.255.254155.46.255.25532,766
95155.47.0.0/17155.47.0.1 to 155.47.127.254155.47.127.25532,766
96155.47.128.0/17155.47.128.1 to 155.47.255.254155.47.255.25532,766
97155.48.0.0/17155.48.0.1 to 155.48.127.254155.48.127.25532,766
98155.48.128.0/17155.48.128.1 to 155.48.255.254155.48.255.25532,766
99155.49.0.0/17155.49.0.1 to 155.49.127.254155.49.127.25532,766
100155.49.128.0/17155.49.128.1 to 155.49.255.254155.49.255.25532,766
101155.50.0.0/17155.50.0.1 to 155.50.127.254155.50.127.25532,766
102155.50.128.0/17155.50.128.1 to 155.50.255.254155.50.255.25532,766
103155.51.0.0/17155.51.0.1 to 155.51.127.254155.51.127.25532,766
104155.51.128.0/17155.51.128.1 to 155.51.255.254155.51.255.25532,766
105155.52.0.0/17155.52.0.1 to 155.52.127.254155.52.127.25532,766
106155.52.128.0/17155.52.128.1 to 155.52.255.254155.52.255.25532,766
107155.53.0.0/17155.53.0.1 to 155.53.127.254155.53.127.25532,766
108155.53.128.0/17155.53.128.1 to 155.53.255.254155.53.255.25532,766
109155.54.0.0/17155.54.0.1 to 155.54.127.254155.54.127.25532,766
110155.54.128.0/17155.54.128.1 to 155.54.255.254155.54.255.25532,766
111155.55.0.0/17155.55.0.1 to 155.55.127.254155.55.127.25532,766
112155.55.128.0/17155.55.128.1 to 155.55.255.254155.55.255.25532,766
113155.56.0.0/17155.56.0.1 to 155.56.127.254155.56.127.25532,766
114155.56.128.0/17155.56.128.1 to 155.56.255.254155.56.255.25532,766
115155.57.0.0/17155.57.0.1 to 155.57.127.254155.57.127.25532,766
116155.57.128.0/17155.57.128.1 to 155.57.255.254155.57.255.25532,766
117155.58.0.0/17155.58.0.1 to 155.58.127.254155.58.127.25532,766
118155.58.128.0/17155.58.128.1 to 155.58.255.254155.58.255.25532,766
119155.59.0.0/17155.59.0.1 to 155.59.127.254155.59.127.25532,766
120155.59.128.0/17155.59.128.1 to 155.59.255.254155.59.255.25532,766
121155.60.0.0/17155.60.0.1 to 155.60.127.254155.60.127.25532,766
122155.60.128.0/17155.60.128.1 to 155.60.255.254155.60.255.25532,766
123155.61.0.0/17155.61.0.1 to 155.61.127.254155.61.127.25532,766
124155.61.128.0/17155.61.128.1 to 155.61.255.254155.61.255.25532,766
125155.62.0.0/17155.62.0.1 to 155.62.127.254155.62.127.25532,766
126155.62.128.0/17155.62.128.1 to 155.62.255.254155.62.255.25532,766
127155.63.0.0/17155.63.0.1 to 155.63.127.254155.63.127.25532,766
128155.63.128.0/17155.63.128.1 to 155.63.255.254155.63.255.25532,766
129155.64.0.0/17155.64.0.1 to 155.64.127.254155.64.127.25532,766
130155.64.128.0/17155.64.128.1 to 155.64.255.254155.64.255.25532,766
131155.65.0.0/17155.65.0.1 to 155.65.127.254155.65.127.25532,766
132155.65.128.0/17155.65.128.1 to 155.65.255.254155.65.255.25532,766
133155.66.0.0/17155.66.0.1 to 155.66.127.254155.66.127.25532,766
134155.66.128.0/17155.66.128.1 to 155.66.255.254155.66.255.25532,766
135155.67.0.0/17155.67.0.1 to 155.67.127.254155.67.127.25532,766
136155.67.128.0/17155.67.128.1 to 155.67.255.254155.67.255.25532,766
137155.68.0.0/17155.68.0.1 to 155.68.127.254155.68.127.25532,766
138155.68.128.0/17155.68.128.1 to 155.68.255.254155.68.255.25532,766
139155.69.0.0/17155.69.0.1 to 155.69.127.254155.69.127.25532,766
140155.69.128.0/17155.69.128.1 to 155.69.255.254155.69.255.25532,766
141155.70.0.0/17155.70.0.1 to 155.70.127.254155.70.127.25532,766
142155.70.128.0/17155.70.128.1 to 155.70.255.254155.70.255.25532,766
143155.71.0.0/17155.71.0.1 to 155.71.127.254155.71.127.25532,766
144155.71.128.0/17155.71.128.1 to 155.71.255.254155.71.255.25532,766
145155.72.0.0/17155.72.0.1 to 155.72.127.254155.72.127.25532,766
146155.72.128.0/17155.72.128.1 to 155.72.255.254155.72.255.25532,766
147155.73.0.0/17155.73.0.1 to 155.73.127.254155.73.127.25532,766
148155.73.128.0/17155.73.128.1 to 155.73.255.254155.73.255.25532,766
149155.74.0.0/17155.74.0.1 to 155.74.127.254155.74.127.25532,766
150155.74.128.0/17155.74.128.1 to 155.74.255.254155.74.255.25532,766
151155.75.0.0/17155.75.0.1 to 155.75.127.254155.75.127.25532,766
152155.75.128.0/17155.75.128.1 to 155.75.255.254155.75.255.25532,766
153155.76.0.0/17155.76.0.1 to 155.76.127.254155.76.127.25532,766
154155.76.128.0/17155.76.128.1 to 155.76.255.254155.76.255.25532,766
155155.77.0.0/17155.77.0.1 to 155.77.127.254155.77.127.25532,766
156155.77.128.0/17155.77.128.1 to 155.77.255.254155.77.255.25532,766
157155.78.0.0/17155.78.0.1 to 155.78.127.254155.78.127.25532,766
158155.78.128.0/17155.78.128.1 to 155.78.255.254155.78.255.25532,766
159155.79.0.0/17155.79.0.1 to 155.79.127.254155.79.127.25532,766
160155.79.128.0/17155.79.128.1 to 155.79.255.254155.79.255.25532,766
161155.80.0.0/17155.80.0.1 to 155.80.127.254155.80.127.25532,766
162155.80.128.0/17155.80.128.1 to 155.80.255.254155.80.255.25532,766
163155.81.0.0/17155.81.0.1 to 155.81.127.254155.81.127.25532,766
164155.81.128.0/17155.81.128.1 to 155.81.255.254155.81.255.25532,766
165155.82.0.0/17155.82.0.1 to 155.82.127.254155.82.127.25532,766
166155.82.128.0/17155.82.128.1 to 155.82.255.254155.82.255.25532,766
167155.83.0.0/17155.83.0.1 to 155.83.127.254155.83.127.25532,766
168155.83.128.0/17155.83.128.1 to 155.83.255.254155.83.255.25532,766
169155.84.0.0/17155.84.0.1 to 155.84.127.254155.84.127.25532,766
170155.84.128.0/17155.84.128.1 to 155.84.255.254155.84.255.25532,766
171155.85.0.0/17155.85.0.1 to 155.85.127.254155.85.127.25532,766
172155.85.128.0/17155.85.128.1 to 155.85.255.254155.85.255.25532,766
173155.86.0.0/17155.86.0.1 to 155.86.127.254155.86.127.25532,766
174155.86.128.0/17155.86.128.1 to 155.86.255.254155.86.255.25532,766
175155.87.0.0/17155.87.0.1 to 155.87.127.254155.87.127.25532,766
176155.87.128.0/17155.87.128.1 to 155.87.255.254155.87.255.25532,766
177155.88.0.0/17155.88.0.1 to 155.88.127.254155.88.127.25532,766
178155.88.128.0/17155.88.128.1 to 155.88.255.254155.88.255.25532,766
179155.89.0.0/17155.89.0.1 to 155.89.127.254155.89.127.25532,766
180155.89.128.0/17155.89.128.1 to 155.89.255.254155.89.255.25532,766
181155.90.0.0/17155.90.0.1 to 155.90.127.254155.90.127.25532,766
182155.90.128.0/17155.90.128.1 to 155.90.255.254155.90.255.25532,766
183155.91.0.0/17155.91.0.1 to 155.91.127.254155.91.127.25532,766
184155.91.128.0/17155.91.128.1 to 155.91.255.254155.91.255.25532,766
185155.92.0.0/17155.92.0.1 to 155.92.127.254155.92.127.25532,766
186155.92.128.0/17155.92.128.1 to 155.92.255.254155.92.255.25532,766
187155.93.0.0/17155.93.0.1 to 155.93.127.254155.93.127.25532,766
188155.93.128.0/17155.93.128.1 to 155.93.255.254155.93.255.25532,766
189155.94.0.0/17155.94.0.1 to 155.94.127.254155.94.127.25532,766
190155.94.128.0/17155.94.128.1 to 155.94.255.254155.94.255.25532,766
191155.95.0.0/17155.95.0.1 to 155.95.127.254155.95.127.25532,766
192155.95.128.0/17155.95.128.1 to 155.95.255.254155.95.255.25532,766
193155.96.0.0/17155.96.0.1 to 155.96.127.254155.96.127.25532,766
194155.96.128.0/17155.96.128.1 to 155.96.255.254155.96.255.25532,766
195155.97.0.0/17155.97.0.1 to 155.97.127.254155.97.127.25532,766
196155.97.128.0/17155.97.128.1 to 155.97.255.254155.97.255.25532,766
197155.98.0.0/17155.98.0.1 to 155.98.127.254155.98.127.25532,766
198155.98.128.0/17155.98.128.1 to 155.98.255.254155.98.255.25532,766
199155.99.0.0/17155.99.0.1 to 155.99.127.254155.99.127.25532,766
200155.99.128.0/17155.99.128.1 to 155.99.255.254155.99.255.25532,766
201155.100.0.0/17155.100.0.1 to 155.100.127.254155.100.127.25532,766
202155.100.128.0/17155.100.128.1 to 155.100.255.254155.100.255.25532,766
203155.101.0.0/17155.101.0.1 to 155.101.127.254155.101.127.25532,766
204155.101.128.0/17155.101.128.1 to 155.101.255.254155.101.255.25532,766
205155.102.0.0/17155.102.0.1 to 155.102.127.254155.102.127.25532,766
206155.102.128.0/17155.102.128.1 to 155.102.255.254155.102.255.25532,766
207155.103.0.0/17155.103.0.1 to 155.103.127.254155.103.127.25532,766
208155.103.128.0/17155.103.128.1 to 155.103.255.254155.103.255.25532,766
209155.104.0.0/17155.104.0.1 to 155.104.127.254155.104.127.25532,766
210155.104.128.0/17155.104.128.1 to 155.104.255.254155.104.255.25532,766
211155.105.0.0/17155.105.0.1 to 155.105.127.254155.105.127.25532,766
212155.105.128.0/17155.105.128.1 to 155.105.255.254155.105.255.25532,766
213155.106.0.0/17155.106.0.1 to 155.106.127.254155.106.127.25532,766
214155.106.128.0/17155.106.128.1 to 155.106.255.254155.106.255.25532,766
215155.107.0.0/17155.107.0.1 to 155.107.127.254155.107.127.25532,766
216155.107.128.0/17155.107.128.1 to 155.107.255.254155.107.255.25532,766
217155.108.0.0/17155.108.0.1 to 155.108.127.254155.108.127.25532,766
218155.108.128.0/17155.108.128.1 to 155.108.255.254155.108.255.25532,766
219155.109.0.0/17155.109.0.1 to 155.109.127.254155.109.127.25532,766
220155.109.128.0/17155.109.128.1 to 155.109.255.254155.109.255.25532,766
221155.110.0.0/17155.110.0.1 to 155.110.127.254155.110.127.25532,766
222155.110.128.0/17155.110.128.1 to 155.110.255.254155.110.255.25532,766
223155.111.0.0/17155.111.0.1 to 155.111.127.254155.111.127.25532,766
224155.111.128.0/17155.111.128.1 to 155.111.255.254155.111.255.25532,766
225155.112.0.0/17155.112.0.1 to 155.112.127.254155.112.127.25532,766
226155.112.128.0/17155.112.128.1 to 155.112.255.254155.112.255.25532,766
227155.113.0.0/17155.113.0.1 to 155.113.127.254155.113.127.25532,766
228155.113.128.0/17155.113.128.1 to 155.113.255.254155.113.255.25532,766
229155.114.0.0/17155.114.0.1 to 155.114.127.254155.114.127.25532,766
230155.114.128.0/17155.114.128.1 to 155.114.255.254155.114.255.25532,766
231155.115.0.0/17155.115.0.1 to 155.115.127.254155.115.127.25532,766
232155.115.128.0/17155.115.128.1 to 155.115.255.254155.115.255.25532,766
233155.116.0.0/17155.116.0.1 to 155.116.127.254155.116.127.25532,766
234155.116.128.0/17155.116.128.1 to 155.116.255.254155.116.255.25532,766
235155.117.0.0/17155.117.0.1 to 155.117.127.254155.117.127.25532,766
236155.117.128.0/17155.117.128.1 to 155.117.255.254155.117.255.25532,766
237155.118.0.0/17155.118.0.1 to 155.118.127.254155.118.127.25532,766
238155.118.128.0/17155.118.128.1 to 155.118.255.254155.118.255.25532,766
239155.119.0.0/17155.119.0.1 to 155.119.127.254155.119.127.25532,766
240155.119.128.0/17155.119.128.1 to 155.119.255.254155.119.255.25532,766
241155.120.0.0/17155.120.0.1 to 155.120.127.254155.120.127.25532,766
242155.120.128.0/17155.120.128.1 to 155.120.255.254155.120.255.25532,766
243155.121.0.0/17155.121.0.1 to 155.121.127.254155.121.127.25532,766
244155.121.128.0/17155.121.128.1 to 155.121.255.254155.121.255.25532,766
245155.122.0.0/17155.122.0.1 to 155.122.127.254155.122.127.25532,766
246155.122.128.0/17155.122.128.1 to 155.122.255.254155.122.255.25532,766
247155.123.0.0/17155.123.0.1 to 155.123.127.254155.123.127.25532,766
248155.123.128.0/17155.123.128.1 to 155.123.255.254155.123.255.25532,766
249155.124.0.0/17155.124.0.1 to 155.124.127.254155.124.127.25532,766
250155.124.128.0/17155.124.128.1 to 155.124.255.254155.124.255.25532,766
251155.125.0.0/17155.125.0.1 to 155.125.127.254155.125.127.25532,766
252155.125.128.0/17155.125.128.1 to 155.125.255.254155.125.255.25532,766
253155.126.0.0/17155.126.0.1 to 155.126.127.254155.126.127.25532,766
254155.126.128.0/17155.126.128.1 to 155.126.255.254155.126.255.25532,766
255155.127.0.0/17155.127.0.1 to 155.127.127.254155.127.127.25532,766
256155.127.128.0/17155.127.128.1 to 155.127.255.254155.127.255.25532,766

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.