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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.

Network166.32.0.0/15
Usable hosts131,070
Subnet mask255.254.0.0
Addresses131,072
Network address
166.32.0.0
Broadcast address
166.33.255.255
First usable
166.32.0.1
Last usable
166.33.255.254
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 A6200000 · Integer 2787115008 to 2787246079
Reverse DNS zones
32.166.in-addr.arpa
33.166.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
Address10100110.00100000.00000000.00000000166.32.0.0
Subnet mask11111111.11111110.00000000.00000000255.254.0.0
Network10100110.00100000.00000000.00000000166.32.0.0
Broadcast10100110.00100001.11111111.11111111166.33.255.255
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)

166.32.0.0/15 makes 2,048 subnets of /26; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1166.32.0.0/26166.32.0.1 to 166.32.0.62166.32.0.6362
2166.32.0.64/26166.32.0.65 to 166.32.0.126166.32.0.12762
3166.32.0.128/26166.32.0.129 to 166.32.0.190166.32.0.19162
4166.32.0.192/26166.32.0.193 to 166.32.0.254166.32.0.25562
5166.32.1.0/26166.32.1.1 to 166.32.1.62166.32.1.6362
6166.32.1.64/26166.32.1.65 to 166.32.1.126166.32.1.12762
7166.32.1.128/26166.32.1.129 to 166.32.1.190166.32.1.19162
8166.32.1.192/26166.32.1.193 to 166.32.1.254166.32.1.25562
9166.32.2.0/26166.32.2.1 to 166.32.2.62166.32.2.6362
10166.32.2.64/26166.32.2.65 to 166.32.2.126166.32.2.12762
11166.32.2.128/26166.32.2.129 to 166.32.2.190166.32.2.19162
12166.32.2.192/26166.32.2.193 to 166.32.2.254166.32.2.25562
13166.32.3.0/26166.32.3.1 to 166.32.3.62166.32.3.6362
14166.32.3.64/26166.32.3.65 to 166.32.3.126166.32.3.12762
15166.32.3.128/26166.32.3.129 to 166.32.3.190166.32.3.19162
16166.32.3.192/26166.32.3.193 to 166.32.3.254166.32.3.25562
17166.32.4.0/26166.32.4.1 to 166.32.4.62166.32.4.6362
18166.32.4.64/26166.32.4.65 to 166.32.4.126166.32.4.12762
19166.32.4.128/26166.32.4.129 to 166.32.4.190166.32.4.19162
20166.32.4.192/26166.32.4.193 to 166.32.4.254166.32.4.25562
21166.32.5.0/26166.32.5.1 to 166.32.5.62166.32.5.6362
22166.32.5.64/26166.32.5.65 to 166.32.5.126166.32.5.12762
23166.32.5.128/26166.32.5.129 to 166.32.5.190166.32.5.19162
24166.32.5.192/26166.32.5.193 to 166.32.5.254166.32.5.25562
25166.32.6.0/26166.32.6.1 to 166.32.6.62166.32.6.6362
26166.32.6.64/26166.32.6.65 to 166.32.6.126166.32.6.12762
27166.32.6.128/26166.32.6.129 to 166.32.6.190166.32.6.19162
28166.32.6.192/26166.32.6.193 to 166.32.6.254166.32.6.25562
29166.32.7.0/26166.32.7.1 to 166.32.7.62166.32.7.6362
30166.32.7.64/26166.32.7.65 to 166.32.7.126166.32.7.12762
31166.32.7.128/26166.32.7.129 to 166.32.7.190166.32.7.19162
32166.32.7.192/26166.32.7.193 to 166.32.7.254166.32.7.25562
33166.32.8.0/26166.32.8.1 to 166.32.8.62166.32.8.6362
34166.32.8.64/26166.32.8.65 to 166.32.8.126166.32.8.12762
35166.32.8.128/26166.32.8.129 to 166.32.8.190166.32.8.19162
36166.32.8.192/26166.32.8.193 to 166.32.8.254166.32.8.25562
37166.32.9.0/26166.32.9.1 to 166.32.9.62166.32.9.6362
38166.32.9.64/26166.32.9.65 to 166.32.9.126166.32.9.12762
39166.32.9.128/26166.32.9.129 to 166.32.9.190166.32.9.19162
40166.32.9.192/26166.32.9.193 to 166.32.9.254166.32.9.25562
41166.32.10.0/26166.32.10.1 to 166.32.10.62166.32.10.6362
42166.32.10.64/26166.32.10.65 to 166.32.10.126166.32.10.12762
43166.32.10.128/26166.32.10.129 to 166.32.10.190166.32.10.19162
44166.32.10.192/26166.32.10.193 to 166.32.10.254166.32.10.25562
45166.32.11.0/26166.32.11.1 to 166.32.11.62166.32.11.6362
46166.32.11.64/26166.32.11.65 to 166.32.11.126166.32.11.12762
47166.32.11.128/26166.32.11.129 to 166.32.11.190166.32.11.19162
48166.32.11.192/26166.32.11.193 to 166.32.11.254166.32.11.25562
49166.32.12.0/26166.32.12.1 to 166.32.12.62166.32.12.6362
50166.32.12.64/26166.32.12.65 to 166.32.12.126166.32.12.12762
51166.32.12.128/26166.32.12.129 to 166.32.12.190166.32.12.19162
52166.32.12.192/26166.32.12.193 to 166.32.12.254166.32.12.25562
53166.32.13.0/26166.32.13.1 to 166.32.13.62166.32.13.6362
54166.32.13.64/26166.32.13.65 to 166.32.13.126166.32.13.12762
55166.32.13.128/26166.32.13.129 to 166.32.13.190166.32.13.19162
56166.32.13.192/26166.32.13.193 to 166.32.13.254166.32.13.25562
57166.32.14.0/26166.32.14.1 to 166.32.14.62166.32.14.6362
58166.32.14.64/26166.32.14.65 to 166.32.14.126166.32.14.12762
59166.32.14.128/26166.32.14.129 to 166.32.14.190166.32.14.19162
60166.32.14.192/26166.32.14.193 to 166.32.14.254166.32.14.25562
61166.32.15.0/26166.32.15.1 to 166.32.15.62166.32.15.6362
62166.32.15.64/26166.32.15.65 to 166.32.15.126166.32.15.12762
63166.32.15.128/26166.32.15.129 to 166.32.15.190166.32.15.19162
64166.32.15.192/26166.32.15.193 to 166.32.15.254166.32.15.25562
65166.32.16.0/26166.32.16.1 to 166.32.16.62166.32.16.6362
66166.32.16.64/26166.32.16.65 to 166.32.16.126166.32.16.12762
67166.32.16.128/26166.32.16.129 to 166.32.16.190166.32.16.19162
68166.32.16.192/26166.32.16.193 to 166.32.16.254166.32.16.25562
69166.32.17.0/26166.32.17.1 to 166.32.17.62166.32.17.6362
70166.32.17.64/26166.32.17.65 to 166.32.17.126166.32.17.12762
71166.32.17.128/26166.32.17.129 to 166.32.17.190166.32.17.19162
72166.32.17.192/26166.32.17.193 to 166.32.17.254166.32.17.25562
73166.32.18.0/26166.32.18.1 to 166.32.18.62166.32.18.6362
74166.32.18.64/26166.32.18.65 to 166.32.18.126166.32.18.12762
75166.32.18.128/26166.32.18.129 to 166.32.18.190166.32.18.19162
76166.32.18.192/26166.32.18.193 to 166.32.18.254166.32.18.25562
77166.32.19.0/26166.32.19.1 to 166.32.19.62166.32.19.6362
78166.32.19.64/26166.32.19.65 to 166.32.19.126166.32.19.12762
79166.32.19.128/26166.32.19.129 to 166.32.19.190166.32.19.19162
80166.32.19.192/26166.32.19.193 to 166.32.19.254166.32.19.25562
81166.32.20.0/26166.32.20.1 to 166.32.20.62166.32.20.6362
82166.32.20.64/26166.32.20.65 to 166.32.20.126166.32.20.12762
83166.32.20.128/26166.32.20.129 to 166.32.20.190166.32.20.19162
84166.32.20.192/26166.32.20.193 to 166.32.20.254166.32.20.25562
85166.32.21.0/26166.32.21.1 to 166.32.21.62166.32.21.6362
86166.32.21.64/26166.32.21.65 to 166.32.21.126166.32.21.12762
87166.32.21.128/26166.32.21.129 to 166.32.21.190166.32.21.19162
88166.32.21.192/26166.32.21.193 to 166.32.21.254166.32.21.25562
89166.32.22.0/26166.32.22.1 to 166.32.22.62166.32.22.6362
90166.32.22.64/26166.32.22.65 to 166.32.22.126166.32.22.12762
91166.32.22.128/26166.32.22.129 to 166.32.22.190166.32.22.19162
92166.32.22.192/26166.32.22.193 to 166.32.22.254166.32.22.25562
93166.32.23.0/26166.32.23.1 to 166.32.23.62166.32.23.6362
94166.32.23.64/26166.32.23.65 to 166.32.23.126166.32.23.12762
95166.32.23.128/26166.32.23.129 to 166.32.23.190166.32.23.19162
96166.32.23.192/26166.32.23.193 to 166.32.23.254166.32.23.25562
97166.32.24.0/26166.32.24.1 to 166.32.24.62166.32.24.6362
98166.32.24.64/26166.32.24.65 to 166.32.24.126166.32.24.12762
99166.32.24.128/26166.32.24.129 to 166.32.24.190166.32.24.19162
100166.32.24.192/26166.32.24.193 to 166.32.24.254166.32.24.25562
101166.32.25.0/26166.32.25.1 to 166.32.25.62166.32.25.6362
102166.32.25.64/26166.32.25.65 to 166.32.25.126166.32.25.12762
103166.32.25.128/26166.32.25.129 to 166.32.25.190166.32.25.19162
104166.32.25.192/26166.32.25.193 to 166.32.25.254166.32.25.25562
105166.32.26.0/26166.32.26.1 to 166.32.26.62166.32.26.6362
106166.32.26.64/26166.32.26.65 to 166.32.26.126166.32.26.12762
107166.32.26.128/26166.32.26.129 to 166.32.26.190166.32.26.19162
108166.32.26.192/26166.32.26.193 to 166.32.26.254166.32.26.25562
109166.32.27.0/26166.32.27.1 to 166.32.27.62166.32.27.6362
110166.32.27.64/26166.32.27.65 to 166.32.27.126166.32.27.12762
111166.32.27.128/26166.32.27.129 to 166.32.27.190166.32.27.19162
112166.32.27.192/26166.32.27.193 to 166.32.27.254166.32.27.25562
113166.32.28.0/26166.32.28.1 to 166.32.28.62166.32.28.6362
114166.32.28.64/26166.32.28.65 to 166.32.28.126166.32.28.12762
115166.32.28.128/26166.32.28.129 to 166.32.28.190166.32.28.19162
116166.32.28.192/26166.32.28.193 to 166.32.28.254166.32.28.25562
117166.32.29.0/26166.32.29.1 to 166.32.29.62166.32.29.6362
118166.32.29.64/26166.32.29.65 to 166.32.29.126166.32.29.12762
119166.32.29.128/26166.32.29.129 to 166.32.29.190166.32.29.19162
120166.32.29.192/26166.32.29.193 to 166.32.29.254166.32.29.25562
121166.32.30.0/26166.32.30.1 to 166.32.30.62166.32.30.6362
122166.32.30.64/26166.32.30.65 to 166.32.30.126166.32.30.12762
123166.32.30.128/26166.32.30.129 to 166.32.30.190166.32.30.19162
124166.32.30.192/26166.32.30.193 to 166.32.30.254166.32.30.25562
125166.32.31.0/26166.32.31.1 to 166.32.31.62166.32.31.6362
126166.32.31.64/26166.32.31.65 to 166.32.31.126166.32.31.12762
127166.32.31.128/26166.32.31.129 to 166.32.31.190166.32.31.19162
128166.32.31.192/26166.32.31.193 to 166.32.31.254166.32.31.25562
129166.32.32.0/26166.32.32.1 to 166.32.32.62166.32.32.6362
130166.32.32.64/26166.32.32.65 to 166.32.32.126166.32.32.12762
131166.32.32.128/26166.32.32.129 to 166.32.32.190166.32.32.19162
132166.32.32.192/26166.32.32.193 to 166.32.32.254166.32.32.25562
133166.32.33.0/26166.32.33.1 to 166.32.33.62166.32.33.6362
134166.32.33.64/26166.32.33.65 to 166.32.33.126166.32.33.12762
135166.32.33.128/26166.32.33.129 to 166.32.33.190166.32.33.19162
136166.32.33.192/26166.32.33.193 to 166.32.33.254166.32.33.25562
137166.32.34.0/26166.32.34.1 to 166.32.34.62166.32.34.6362
138166.32.34.64/26166.32.34.65 to 166.32.34.126166.32.34.12762
139166.32.34.128/26166.32.34.129 to 166.32.34.190166.32.34.19162
140166.32.34.192/26166.32.34.193 to 166.32.34.254166.32.34.25562
141166.32.35.0/26166.32.35.1 to 166.32.35.62166.32.35.6362
142166.32.35.64/26166.32.35.65 to 166.32.35.126166.32.35.12762
143166.32.35.128/26166.32.35.129 to 166.32.35.190166.32.35.19162
144166.32.35.192/26166.32.35.193 to 166.32.35.254166.32.35.25562
145166.32.36.0/26166.32.36.1 to 166.32.36.62166.32.36.6362
146166.32.36.64/26166.32.36.65 to 166.32.36.126166.32.36.12762
147166.32.36.128/26166.32.36.129 to 166.32.36.190166.32.36.19162
148166.32.36.192/26166.32.36.193 to 166.32.36.254166.32.36.25562
149166.32.37.0/26166.32.37.1 to 166.32.37.62166.32.37.6362
150166.32.37.64/26166.32.37.65 to 166.32.37.126166.32.37.12762
151166.32.37.128/26166.32.37.129 to 166.32.37.190166.32.37.19162
152166.32.37.192/26166.32.37.193 to 166.32.37.254166.32.37.25562
153166.32.38.0/26166.32.38.1 to 166.32.38.62166.32.38.6362
154166.32.38.64/26166.32.38.65 to 166.32.38.126166.32.38.12762
155166.32.38.128/26166.32.38.129 to 166.32.38.190166.32.38.19162
156166.32.38.192/26166.32.38.193 to 166.32.38.254166.32.38.25562
157166.32.39.0/26166.32.39.1 to 166.32.39.62166.32.39.6362
158166.32.39.64/26166.32.39.65 to 166.32.39.126166.32.39.12762
159166.32.39.128/26166.32.39.129 to 166.32.39.190166.32.39.19162
160166.32.39.192/26166.32.39.193 to 166.32.39.254166.32.39.25562
161166.32.40.0/26166.32.40.1 to 166.32.40.62166.32.40.6362
162166.32.40.64/26166.32.40.65 to 166.32.40.126166.32.40.12762
163166.32.40.128/26166.32.40.129 to 166.32.40.190166.32.40.19162
164166.32.40.192/26166.32.40.193 to 166.32.40.254166.32.40.25562
165166.32.41.0/26166.32.41.1 to 166.32.41.62166.32.41.6362
166166.32.41.64/26166.32.41.65 to 166.32.41.126166.32.41.12762
167166.32.41.128/26166.32.41.129 to 166.32.41.190166.32.41.19162
168166.32.41.192/26166.32.41.193 to 166.32.41.254166.32.41.25562
169166.32.42.0/26166.32.42.1 to 166.32.42.62166.32.42.6362
170166.32.42.64/26166.32.42.65 to 166.32.42.126166.32.42.12762
171166.32.42.128/26166.32.42.129 to 166.32.42.190166.32.42.19162
172166.32.42.192/26166.32.42.193 to 166.32.42.254166.32.42.25562
173166.32.43.0/26166.32.43.1 to 166.32.43.62166.32.43.6362
174166.32.43.64/26166.32.43.65 to 166.32.43.126166.32.43.12762
175166.32.43.128/26166.32.43.129 to 166.32.43.190166.32.43.19162
176166.32.43.192/26166.32.43.193 to 166.32.43.254166.32.43.25562
177166.32.44.0/26166.32.44.1 to 166.32.44.62166.32.44.6362
178166.32.44.64/26166.32.44.65 to 166.32.44.126166.32.44.12762
179166.32.44.128/26166.32.44.129 to 166.32.44.190166.32.44.19162
180166.32.44.192/26166.32.44.193 to 166.32.44.254166.32.44.25562
181166.32.45.0/26166.32.45.1 to 166.32.45.62166.32.45.6362
182166.32.45.64/26166.32.45.65 to 166.32.45.126166.32.45.12762
183166.32.45.128/26166.32.45.129 to 166.32.45.190166.32.45.19162
184166.32.45.192/26166.32.45.193 to 166.32.45.254166.32.45.25562
185166.32.46.0/26166.32.46.1 to 166.32.46.62166.32.46.6362
186166.32.46.64/26166.32.46.65 to 166.32.46.126166.32.46.12762
187166.32.46.128/26166.32.46.129 to 166.32.46.190166.32.46.19162
188166.32.46.192/26166.32.46.193 to 166.32.46.254166.32.46.25562
189166.32.47.0/26166.32.47.1 to 166.32.47.62166.32.47.6362
190166.32.47.64/26166.32.47.65 to 166.32.47.126166.32.47.12762
191166.32.47.128/26166.32.47.129 to 166.32.47.190166.32.47.19162
192166.32.47.192/26166.32.47.193 to 166.32.47.254166.32.47.25562
193166.32.48.0/26166.32.48.1 to 166.32.48.62166.32.48.6362
194166.32.48.64/26166.32.48.65 to 166.32.48.126166.32.48.12762
195166.32.48.128/26166.32.48.129 to 166.32.48.190166.32.48.19162
196166.32.48.192/26166.32.48.193 to 166.32.48.254166.32.48.25562
197166.32.49.0/26166.32.49.1 to 166.32.49.62166.32.49.6362
198166.32.49.64/26166.32.49.65 to 166.32.49.126166.32.49.12762
199166.32.49.128/26166.32.49.129 to 166.32.49.190166.32.49.19162
200166.32.49.192/26166.32.49.193 to 166.32.49.254166.32.49.25562
201166.32.50.0/26166.32.50.1 to 166.32.50.62166.32.50.6362
202166.32.50.64/26166.32.50.65 to 166.32.50.126166.32.50.12762
203166.32.50.128/26166.32.50.129 to 166.32.50.190166.32.50.19162
204166.32.50.192/26166.32.50.193 to 166.32.50.254166.32.50.25562
205166.32.51.0/26166.32.51.1 to 166.32.51.62166.32.51.6362
206166.32.51.64/26166.32.51.65 to 166.32.51.126166.32.51.12762
207166.32.51.128/26166.32.51.129 to 166.32.51.190166.32.51.19162
208166.32.51.192/26166.32.51.193 to 166.32.51.254166.32.51.25562
209166.32.52.0/26166.32.52.1 to 166.32.52.62166.32.52.6362
210166.32.52.64/26166.32.52.65 to 166.32.52.126166.32.52.12762
211166.32.52.128/26166.32.52.129 to 166.32.52.190166.32.52.19162
212166.32.52.192/26166.32.52.193 to 166.32.52.254166.32.52.25562
213166.32.53.0/26166.32.53.1 to 166.32.53.62166.32.53.6362
214166.32.53.64/26166.32.53.65 to 166.32.53.126166.32.53.12762
215166.32.53.128/26166.32.53.129 to 166.32.53.190166.32.53.19162
216166.32.53.192/26166.32.53.193 to 166.32.53.254166.32.53.25562
217166.32.54.0/26166.32.54.1 to 166.32.54.62166.32.54.6362
218166.32.54.64/26166.32.54.65 to 166.32.54.126166.32.54.12762
219166.32.54.128/26166.32.54.129 to 166.32.54.190166.32.54.19162
220166.32.54.192/26166.32.54.193 to 166.32.54.254166.32.54.25562
221166.32.55.0/26166.32.55.1 to 166.32.55.62166.32.55.6362
222166.32.55.64/26166.32.55.65 to 166.32.55.126166.32.55.12762
223166.32.55.128/26166.32.55.129 to 166.32.55.190166.32.55.19162
224166.32.55.192/26166.32.55.193 to 166.32.55.254166.32.55.25562
225166.32.56.0/26166.32.56.1 to 166.32.56.62166.32.56.6362
226166.32.56.64/26166.32.56.65 to 166.32.56.126166.32.56.12762
227166.32.56.128/26166.32.56.129 to 166.32.56.190166.32.56.19162
228166.32.56.192/26166.32.56.193 to 166.32.56.254166.32.56.25562
229166.32.57.0/26166.32.57.1 to 166.32.57.62166.32.57.6362
230166.32.57.64/26166.32.57.65 to 166.32.57.126166.32.57.12762
231166.32.57.128/26166.32.57.129 to 166.32.57.190166.32.57.19162
232166.32.57.192/26166.32.57.193 to 166.32.57.254166.32.57.25562
233166.32.58.0/26166.32.58.1 to 166.32.58.62166.32.58.6362
234166.32.58.64/26166.32.58.65 to 166.32.58.126166.32.58.12762
235166.32.58.128/26166.32.58.129 to 166.32.58.190166.32.58.19162
236166.32.58.192/26166.32.58.193 to 166.32.58.254166.32.58.25562
237166.32.59.0/26166.32.59.1 to 166.32.59.62166.32.59.6362
238166.32.59.64/26166.32.59.65 to 166.32.59.126166.32.59.12762
239166.32.59.128/26166.32.59.129 to 166.32.59.190166.32.59.19162
240166.32.59.192/26166.32.59.193 to 166.32.59.254166.32.59.25562
241166.32.60.0/26166.32.60.1 to 166.32.60.62166.32.60.6362
242166.32.60.64/26166.32.60.65 to 166.32.60.126166.32.60.12762
243166.32.60.128/26166.32.60.129 to 166.32.60.190166.32.60.19162
244166.32.60.192/26166.32.60.193 to 166.32.60.254166.32.60.25562
245166.32.61.0/26166.32.61.1 to 166.32.61.62166.32.61.6362
246166.32.61.64/26166.32.61.65 to 166.32.61.126166.32.61.12762
247166.32.61.128/26166.32.61.129 to 166.32.61.190166.32.61.19162
248166.32.61.192/26166.32.61.193 to 166.32.61.254166.32.61.25562
249166.32.62.0/26166.32.62.1 to 166.32.62.62166.32.62.6362
250166.32.62.64/26166.32.62.65 to 166.32.62.126166.32.62.12762
251166.32.62.128/26166.32.62.129 to 166.32.62.190166.32.62.19162
252166.32.62.192/26166.32.62.193 to 166.32.62.254166.32.62.25562
253166.32.63.0/26166.32.63.1 to 166.32.63.62166.32.63.6362
254166.32.63.64/26166.32.63.65 to 166.32.63.126166.32.63.12762
255166.32.63.128/26166.32.63.129 to 166.32.63.190166.32.63.19162
256166.32.63.192/26166.32.63.193 to 166.32.63.254166.32.63.25562

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.