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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/26
/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 2,048 subnets of /26; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1155.166.0.0/26155.166.0.1 to 155.166.0.62155.166.0.6362
2155.166.0.64/26155.166.0.65 to 155.166.0.126155.166.0.12762
3155.166.0.128/26155.166.0.129 to 155.166.0.190155.166.0.19162
4155.166.0.192/26155.166.0.193 to 155.166.0.254155.166.0.25562
5155.166.1.0/26155.166.1.1 to 155.166.1.62155.166.1.6362
6155.166.1.64/26155.166.1.65 to 155.166.1.126155.166.1.12762
7155.166.1.128/26155.166.1.129 to 155.166.1.190155.166.1.19162
8155.166.1.192/26155.166.1.193 to 155.166.1.254155.166.1.25562
9155.166.2.0/26155.166.2.1 to 155.166.2.62155.166.2.6362
10155.166.2.64/26155.166.2.65 to 155.166.2.126155.166.2.12762
11155.166.2.128/26155.166.2.129 to 155.166.2.190155.166.2.19162
12155.166.2.192/26155.166.2.193 to 155.166.2.254155.166.2.25562
13155.166.3.0/26155.166.3.1 to 155.166.3.62155.166.3.6362
14155.166.3.64/26155.166.3.65 to 155.166.3.126155.166.3.12762
15155.166.3.128/26155.166.3.129 to 155.166.3.190155.166.3.19162
16155.166.3.192/26155.166.3.193 to 155.166.3.254155.166.3.25562
17155.166.4.0/26155.166.4.1 to 155.166.4.62155.166.4.6362
18155.166.4.64/26155.166.4.65 to 155.166.4.126155.166.4.12762
19155.166.4.128/26155.166.4.129 to 155.166.4.190155.166.4.19162
20155.166.4.192/26155.166.4.193 to 155.166.4.254155.166.4.25562
21155.166.5.0/26155.166.5.1 to 155.166.5.62155.166.5.6362
22155.166.5.64/26155.166.5.65 to 155.166.5.126155.166.5.12762
23155.166.5.128/26155.166.5.129 to 155.166.5.190155.166.5.19162
24155.166.5.192/26155.166.5.193 to 155.166.5.254155.166.5.25562
25155.166.6.0/26155.166.6.1 to 155.166.6.62155.166.6.6362
26155.166.6.64/26155.166.6.65 to 155.166.6.126155.166.6.12762
27155.166.6.128/26155.166.6.129 to 155.166.6.190155.166.6.19162
28155.166.6.192/26155.166.6.193 to 155.166.6.254155.166.6.25562
29155.166.7.0/26155.166.7.1 to 155.166.7.62155.166.7.6362
30155.166.7.64/26155.166.7.65 to 155.166.7.126155.166.7.12762
31155.166.7.128/26155.166.7.129 to 155.166.7.190155.166.7.19162
32155.166.7.192/26155.166.7.193 to 155.166.7.254155.166.7.25562
33155.166.8.0/26155.166.8.1 to 155.166.8.62155.166.8.6362
34155.166.8.64/26155.166.8.65 to 155.166.8.126155.166.8.12762
35155.166.8.128/26155.166.8.129 to 155.166.8.190155.166.8.19162
36155.166.8.192/26155.166.8.193 to 155.166.8.254155.166.8.25562
37155.166.9.0/26155.166.9.1 to 155.166.9.62155.166.9.6362
38155.166.9.64/26155.166.9.65 to 155.166.9.126155.166.9.12762
39155.166.9.128/26155.166.9.129 to 155.166.9.190155.166.9.19162
40155.166.9.192/26155.166.9.193 to 155.166.9.254155.166.9.25562
41155.166.10.0/26155.166.10.1 to 155.166.10.62155.166.10.6362
42155.166.10.64/26155.166.10.65 to 155.166.10.126155.166.10.12762
43155.166.10.128/26155.166.10.129 to 155.166.10.190155.166.10.19162
44155.166.10.192/26155.166.10.193 to 155.166.10.254155.166.10.25562
45155.166.11.0/26155.166.11.1 to 155.166.11.62155.166.11.6362
46155.166.11.64/26155.166.11.65 to 155.166.11.126155.166.11.12762
47155.166.11.128/26155.166.11.129 to 155.166.11.190155.166.11.19162
48155.166.11.192/26155.166.11.193 to 155.166.11.254155.166.11.25562
49155.166.12.0/26155.166.12.1 to 155.166.12.62155.166.12.6362
50155.166.12.64/26155.166.12.65 to 155.166.12.126155.166.12.12762
51155.166.12.128/26155.166.12.129 to 155.166.12.190155.166.12.19162
52155.166.12.192/26155.166.12.193 to 155.166.12.254155.166.12.25562
53155.166.13.0/26155.166.13.1 to 155.166.13.62155.166.13.6362
54155.166.13.64/26155.166.13.65 to 155.166.13.126155.166.13.12762
55155.166.13.128/26155.166.13.129 to 155.166.13.190155.166.13.19162
56155.166.13.192/26155.166.13.193 to 155.166.13.254155.166.13.25562
57155.166.14.0/26155.166.14.1 to 155.166.14.62155.166.14.6362
58155.166.14.64/26155.166.14.65 to 155.166.14.126155.166.14.12762
59155.166.14.128/26155.166.14.129 to 155.166.14.190155.166.14.19162
60155.166.14.192/26155.166.14.193 to 155.166.14.254155.166.14.25562
61155.166.15.0/26155.166.15.1 to 155.166.15.62155.166.15.6362
62155.166.15.64/26155.166.15.65 to 155.166.15.126155.166.15.12762
63155.166.15.128/26155.166.15.129 to 155.166.15.190155.166.15.19162
64155.166.15.192/26155.166.15.193 to 155.166.15.254155.166.15.25562
65155.166.16.0/26155.166.16.1 to 155.166.16.62155.166.16.6362
66155.166.16.64/26155.166.16.65 to 155.166.16.126155.166.16.12762
67155.166.16.128/26155.166.16.129 to 155.166.16.190155.166.16.19162
68155.166.16.192/26155.166.16.193 to 155.166.16.254155.166.16.25562
69155.166.17.0/26155.166.17.1 to 155.166.17.62155.166.17.6362
70155.166.17.64/26155.166.17.65 to 155.166.17.126155.166.17.12762
71155.166.17.128/26155.166.17.129 to 155.166.17.190155.166.17.19162
72155.166.17.192/26155.166.17.193 to 155.166.17.254155.166.17.25562
73155.166.18.0/26155.166.18.1 to 155.166.18.62155.166.18.6362
74155.166.18.64/26155.166.18.65 to 155.166.18.126155.166.18.12762
75155.166.18.128/26155.166.18.129 to 155.166.18.190155.166.18.19162
76155.166.18.192/26155.166.18.193 to 155.166.18.254155.166.18.25562
77155.166.19.0/26155.166.19.1 to 155.166.19.62155.166.19.6362
78155.166.19.64/26155.166.19.65 to 155.166.19.126155.166.19.12762
79155.166.19.128/26155.166.19.129 to 155.166.19.190155.166.19.19162
80155.166.19.192/26155.166.19.193 to 155.166.19.254155.166.19.25562
81155.166.20.0/26155.166.20.1 to 155.166.20.62155.166.20.6362
82155.166.20.64/26155.166.20.65 to 155.166.20.126155.166.20.12762
83155.166.20.128/26155.166.20.129 to 155.166.20.190155.166.20.19162
84155.166.20.192/26155.166.20.193 to 155.166.20.254155.166.20.25562
85155.166.21.0/26155.166.21.1 to 155.166.21.62155.166.21.6362
86155.166.21.64/26155.166.21.65 to 155.166.21.126155.166.21.12762
87155.166.21.128/26155.166.21.129 to 155.166.21.190155.166.21.19162
88155.166.21.192/26155.166.21.193 to 155.166.21.254155.166.21.25562
89155.166.22.0/26155.166.22.1 to 155.166.22.62155.166.22.6362
90155.166.22.64/26155.166.22.65 to 155.166.22.126155.166.22.12762
91155.166.22.128/26155.166.22.129 to 155.166.22.190155.166.22.19162
92155.166.22.192/26155.166.22.193 to 155.166.22.254155.166.22.25562
93155.166.23.0/26155.166.23.1 to 155.166.23.62155.166.23.6362
94155.166.23.64/26155.166.23.65 to 155.166.23.126155.166.23.12762
95155.166.23.128/26155.166.23.129 to 155.166.23.190155.166.23.19162
96155.166.23.192/26155.166.23.193 to 155.166.23.254155.166.23.25562
97155.166.24.0/26155.166.24.1 to 155.166.24.62155.166.24.6362
98155.166.24.64/26155.166.24.65 to 155.166.24.126155.166.24.12762
99155.166.24.128/26155.166.24.129 to 155.166.24.190155.166.24.19162
100155.166.24.192/26155.166.24.193 to 155.166.24.254155.166.24.25562
101155.166.25.0/26155.166.25.1 to 155.166.25.62155.166.25.6362
102155.166.25.64/26155.166.25.65 to 155.166.25.126155.166.25.12762
103155.166.25.128/26155.166.25.129 to 155.166.25.190155.166.25.19162
104155.166.25.192/26155.166.25.193 to 155.166.25.254155.166.25.25562
105155.166.26.0/26155.166.26.1 to 155.166.26.62155.166.26.6362
106155.166.26.64/26155.166.26.65 to 155.166.26.126155.166.26.12762
107155.166.26.128/26155.166.26.129 to 155.166.26.190155.166.26.19162
108155.166.26.192/26155.166.26.193 to 155.166.26.254155.166.26.25562
109155.166.27.0/26155.166.27.1 to 155.166.27.62155.166.27.6362
110155.166.27.64/26155.166.27.65 to 155.166.27.126155.166.27.12762
111155.166.27.128/26155.166.27.129 to 155.166.27.190155.166.27.19162
112155.166.27.192/26155.166.27.193 to 155.166.27.254155.166.27.25562
113155.166.28.0/26155.166.28.1 to 155.166.28.62155.166.28.6362
114155.166.28.64/26155.166.28.65 to 155.166.28.126155.166.28.12762
115155.166.28.128/26155.166.28.129 to 155.166.28.190155.166.28.19162
116155.166.28.192/26155.166.28.193 to 155.166.28.254155.166.28.25562
117155.166.29.0/26155.166.29.1 to 155.166.29.62155.166.29.6362
118155.166.29.64/26155.166.29.65 to 155.166.29.126155.166.29.12762
119155.166.29.128/26155.166.29.129 to 155.166.29.190155.166.29.19162
120155.166.29.192/26155.166.29.193 to 155.166.29.254155.166.29.25562
121155.166.30.0/26155.166.30.1 to 155.166.30.62155.166.30.6362
122155.166.30.64/26155.166.30.65 to 155.166.30.126155.166.30.12762
123155.166.30.128/26155.166.30.129 to 155.166.30.190155.166.30.19162
124155.166.30.192/26155.166.30.193 to 155.166.30.254155.166.30.25562
125155.166.31.0/26155.166.31.1 to 155.166.31.62155.166.31.6362
126155.166.31.64/26155.166.31.65 to 155.166.31.126155.166.31.12762
127155.166.31.128/26155.166.31.129 to 155.166.31.190155.166.31.19162
128155.166.31.192/26155.166.31.193 to 155.166.31.254155.166.31.25562
129155.166.32.0/26155.166.32.1 to 155.166.32.62155.166.32.6362
130155.166.32.64/26155.166.32.65 to 155.166.32.126155.166.32.12762
131155.166.32.128/26155.166.32.129 to 155.166.32.190155.166.32.19162
132155.166.32.192/26155.166.32.193 to 155.166.32.254155.166.32.25562
133155.166.33.0/26155.166.33.1 to 155.166.33.62155.166.33.6362
134155.166.33.64/26155.166.33.65 to 155.166.33.126155.166.33.12762
135155.166.33.128/26155.166.33.129 to 155.166.33.190155.166.33.19162
136155.166.33.192/26155.166.33.193 to 155.166.33.254155.166.33.25562
137155.166.34.0/26155.166.34.1 to 155.166.34.62155.166.34.6362
138155.166.34.64/26155.166.34.65 to 155.166.34.126155.166.34.12762
139155.166.34.128/26155.166.34.129 to 155.166.34.190155.166.34.19162
140155.166.34.192/26155.166.34.193 to 155.166.34.254155.166.34.25562
141155.166.35.0/26155.166.35.1 to 155.166.35.62155.166.35.6362
142155.166.35.64/26155.166.35.65 to 155.166.35.126155.166.35.12762
143155.166.35.128/26155.166.35.129 to 155.166.35.190155.166.35.19162
144155.166.35.192/26155.166.35.193 to 155.166.35.254155.166.35.25562
145155.166.36.0/26155.166.36.1 to 155.166.36.62155.166.36.6362
146155.166.36.64/26155.166.36.65 to 155.166.36.126155.166.36.12762
147155.166.36.128/26155.166.36.129 to 155.166.36.190155.166.36.19162
148155.166.36.192/26155.166.36.193 to 155.166.36.254155.166.36.25562
149155.166.37.0/26155.166.37.1 to 155.166.37.62155.166.37.6362
150155.166.37.64/26155.166.37.65 to 155.166.37.126155.166.37.12762
151155.166.37.128/26155.166.37.129 to 155.166.37.190155.166.37.19162
152155.166.37.192/26155.166.37.193 to 155.166.37.254155.166.37.25562
153155.166.38.0/26155.166.38.1 to 155.166.38.62155.166.38.6362
154155.166.38.64/26155.166.38.65 to 155.166.38.126155.166.38.12762
155155.166.38.128/26155.166.38.129 to 155.166.38.190155.166.38.19162
156155.166.38.192/26155.166.38.193 to 155.166.38.254155.166.38.25562
157155.166.39.0/26155.166.39.1 to 155.166.39.62155.166.39.6362
158155.166.39.64/26155.166.39.65 to 155.166.39.126155.166.39.12762
159155.166.39.128/26155.166.39.129 to 155.166.39.190155.166.39.19162
160155.166.39.192/26155.166.39.193 to 155.166.39.254155.166.39.25562
161155.166.40.0/26155.166.40.1 to 155.166.40.62155.166.40.6362
162155.166.40.64/26155.166.40.65 to 155.166.40.126155.166.40.12762
163155.166.40.128/26155.166.40.129 to 155.166.40.190155.166.40.19162
164155.166.40.192/26155.166.40.193 to 155.166.40.254155.166.40.25562
165155.166.41.0/26155.166.41.1 to 155.166.41.62155.166.41.6362
166155.166.41.64/26155.166.41.65 to 155.166.41.126155.166.41.12762
167155.166.41.128/26155.166.41.129 to 155.166.41.190155.166.41.19162
168155.166.41.192/26155.166.41.193 to 155.166.41.254155.166.41.25562
169155.166.42.0/26155.166.42.1 to 155.166.42.62155.166.42.6362
170155.166.42.64/26155.166.42.65 to 155.166.42.126155.166.42.12762
171155.166.42.128/26155.166.42.129 to 155.166.42.190155.166.42.19162
172155.166.42.192/26155.166.42.193 to 155.166.42.254155.166.42.25562
173155.166.43.0/26155.166.43.1 to 155.166.43.62155.166.43.6362
174155.166.43.64/26155.166.43.65 to 155.166.43.126155.166.43.12762
175155.166.43.128/26155.166.43.129 to 155.166.43.190155.166.43.19162
176155.166.43.192/26155.166.43.193 to 155.166.43.254155.166.43.25562
177155.166.44.0/26155.166.44.1 to 155.166.44.62155.166.44.6362
178155.166.44.64/26155.166.44.65 to 155.166.44.126155.166.44.12762
179155.166.44.128/26155.166.44.129 to 155.166.44.190155.166.44.19162
180155.166.44.192/26155.166.44.193 to 155.166.44.254155.166.44.25562
181155.166.45.0/26155.166.45.1 to 155.166.45.62155.166.45.6362
182155.166.45.64/26155.166.45.65 to 155.166.45.126155.166.45.12762
183155.166.45.128/26155.166.45.129 to 155.166.45.190155.166.45.19162
184155.166.45.192/26155.166.45.193 to 155.166.45.254155.166.45.25562
185155.166.46.0/26155.166.46.1 to 155.166.46.62155.166.46.6362
186155.166.46.64/26155.166.46.65 to 155.166.46.126155.166.46.12762
187155.166.46.128/26155.166.46.129 to 155.166.46.190155.166.46.19162
188155.166.46.192/26155.166.46.193 to 155.166.46.254155.166.46.25562
189155.166.47.0/26155.166.47.1 to 155.166.47.62155.166.47.6362
190155.166.47.64/26155.166.47.65 to 155.166.47.126155.166.47.12762
191155.166.47.128/26155.166.47.129 to 155.166.47.190155.166.47.19162
192155.166.47.192/26155.166.47.193 to 155.166.47.254155.166.47.25562
193155.166.48.0/26155.166.48.1 to 155.166.48.62155.166.48.6362
194155.166.48.64/26155.166.48.65 to 155.166.48.126155.166.48.12762
195155.166.48.128/26155.166.48.129 to 155.166.48.190155.166.48.19162
196155.166.48.192/26155.166.48.193 to 155.166.48.254155.166.48.25562
197155.166.49.0/26155.166.49.1 to 155.166.49.62155.166.49.6362
198155.166.49.64/26155.166.49.65 to 155.166.49.126155.166.49.12762
199155.166.49.128/26155.166.49.129 to 155.166.49.190155.166.49.19162
200155.166.49.192/26155.166.49.193 to 155.166.49.254155.166.49.25562
201155.166.50.0/26155.166.50.1 to 155.166.50.62155.166.50.6362
202155.166.50.64/26155.166.50.65 to 155.166.50.126155.166.50.12762
203155.166.50.128/26155.166.50.129 to 155.166.50.190155.166.50.19162
204155.166.50.192/26155.166.50.193 to 155.166.50.254155.166.50.25562
205155.166.51.0/26155.166.51.1 to 155.166.51.62155.166.51.6362
206155.166.51.64/26155.166.51.65 to 155.166.51.126155.166.51.12762
207155.166.51.128/26155.166.51.129 to 155.166.51.190155.166.51.19162
208155.166.51.192/26155.166.51.193 to 155.166.51.254155.166.51.25562
209155.166.52.0/26155.166.52.1 to 155.166.52.62155.166.52.6362
210155.166.52.64/26155.166.52.65 to 155.166.52.126155.166.52.12762
211155.166.52.128/26155.166.52.129 to 155.166.52.190155.166.52.19162
212155.166.52.192/26155.166.52.193 to 155.166.52.254155.166.52.25562
213155.166.53.0/26155.166.53.1 to 155.166.53.62155.166.53.6362
214155.166.53.64/26155.166.53.65 to 155.166.53.126155.166.53.12762
215155.166.53.128/26155.166.53.129 to 155.166.53.190155.166.53.19162
216155.166.53.192/26155.166.53.193 to 155.166.53.254155.166.53.25562
217155.166.54.0/26155.166.54.1 to 155.166.54.62155.166.54.6362
218155.166.54.64/26155.166.54.65 to 155.166.54.126155.166.54.12762
219155.166.54.128/26155.166.54.129 to 155.166.54.190155.166.54.19162
220155.166.54.192/26155.166.54.193 to 155.166.54.254155.166.54.25562
221155.166.55.0/26155.166.55.1 to 155.166.55.62155.166.55.6362
222155.166.55.64/26155.166.55.65 to 155.166.55.126155.166.55.12762
223155.166.55.128/26155.166.55.129 to 155.166.55.190155.166.55.19162
224155.166.55.192/26155.166.55.193 to 155.166.55.254155.166.55.25562
225155.166.56.0/26155.166.56.1 to 155.166.56.62155.166.56.6362
226155.166.56.64/26155.166.56.65 to 155.166.56.126155.166.56.12762
227155.166.56.128/26155.166.56.129 to 155.166.56.190155.166.56.19162
228155.166.56.192/26155.166.56.193 to 155.166.56.254155.166.56.25562
229155.166.57.0/26155.166.57.1 to 155.166.57.62155.166.57.6362
230155.166.57.64/26155.166.57.65 to 155.166.57.126155.166.57.12762
231155.166.57.128/26155.166.57.129 to 155.166.57.190155.166.57.19162
232155.166.57.192/26155.166.57.193 to 155.166.57.254155.166.57.25562
233155.166.58.0/26155.166.58.1 to 155.166.58.62155.166.58.6362
234155.166.58.64/26155.166.58.65 to 155.166.58.126155.166.58.12762
235155.166.58.128/26155.166.58.129 to 155.166.58.190155.166.58.19162
236155.166.58.192/26155.166.58.193 to 155.166.58.254155.166.58.25562
237155.166.59.0/26155.166.59.1 to 155.166.59.62155.166.59.6362
238155.166.59.64/26155.166.59.65 to 155.166.59.126155.166.59.12762
239155.166.59.128/26155.166.59.129 to 155.166.59.190155.166.59.19162
240155.166.59.192/26155.166.59.193 to 155.166.59.254155.166.59.25562
241155.166.60.0/26155.166.60.1 to 155.166.60.62155.166.60.6362
242155.166.60.64/26155.166.60.65 to 155.166.60.126155.166.60.12762
243155.166.60.128/26155.166.60.129 to 155.166.60.190155.166.60.19162
244155.166.60.192/26155.166.60.193 to 155.166.60.254155.166.60.25562
245155.166.61.0/26155.166.61.1 to 155.166.61.62155.166.61.6362
246155.166.61.64/26155.166.61.65 to 155.166.61.126155.166.61.12762
247155.166.61.128/26155.166.61.129 to 155.166.61.190155.166.61.19162
248155.166.61.192/26155.166.61.193 to 155.166.61.254155.166.61.25562
249155.166.62.0/26155.166.62.1 to 155.166.62.62155.166.62.6362
250155.166.62.64/26155.166.62.65 to 155.166.62.126155.166.62.12762
251155.166.62.128/26155.166.62.129 to 155.166.62.190155.166.62.19162
252155.166.62.192/26155.166.62.193 to 155.166.62.254155.166.62.25562
253155.166.63.0/26155.166.63.1 to 155.166.63.62155.166.63.6362
254155.166.63.64/26155.166.63.65 to 155.166.63.126155.166.63.12762
255155.166.63.128/26155.166.63.129 to 155.166.63.190155.166.63.19162
256155.166.63.192/26155.166.63.193 to 155.166.63.254155.166.63.25562

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.