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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.

Network122.3.0.0/19
Usable hosts8,190
Subnet mask255.255.224.0
Addresses8,192
Network address
122.3.0.0
Broadcast address
122.3.31.255
First usable
122.3.0.1
Last usable
122.3.31.254
Usable hosts
8,190 (8,192 less the network and broadcast addresses)
Subnet mask
255.255.224.0
Wildcard mask
0.0.31.255 (Cisco ACLs, OSPF)
Prefix length
/19
Type
Public public
Old class
A (default /8)
As numbers
Hex 7A030000 · Integer 2047016960 to 2047025151
Reverse DNS zones
0.3.122.in-addr.arpa
1.3.122.in-addr.arpa
2.3.122.in-addr.arpa
3.3.122.in-addr.arpa
4.3.122.in-addr.arpa
5.3.122.in-addr.arpa
6.3.122.in-addr.arpa
7.3.122.in-addr.arpa
8.3.122.in-addr.arpa
9.3.122.in-addr.arpa
10.3.122.in-addr.arpa
11.3.122.in-addr.arpa
12.3.122.in-addr.arpa
13.3.122.in-addr.arpa
14.3.122.in-addr.arpa
15.3.122.in-addr.arpa
and 16 more
/19 is not on a 8-bit boundary, so it takes 32 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01111010.00000011.00000000.00000000122.3.0.0
Subnet mask11111111.11111111.11100000.00000000255.255.224.0
Network01111010.00000011.00000000.00000000122.3.0.0
Broadcast01111010.00000011.00011111.11111111122.3.31.255
Split into smaller subnets/27
/20 (2)/21 (4)/22 (8)/23 (16)/24 (32)/25 (64)/26 (128)/27 (256)/28 (512)/29 (1,024)/30 (2,048)/31 (4,096)

122.3.0.0/19 makes 256 subnets of /27.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1122.3.0.0/27122.3.0.1 to 122.3.0.30122.3.0.3130
2122.3.0.32/27122.3.0.33 to 122.3.0.62122.3.0.6330
3122.3.0.64/27122.3.0.65 to 122.3.0.94122.3.0.9530
4122.3.0.96/27122.3.0.97 to 122.3.0.126122.3.0.12730
5122.3.0.128/27122.3.0.129 to 122.3.0.158122.3.0.15930
6122.3.0.160/27122.3.0.161 to 122.3.0.190122.3.0.19130
7122.3.0.192/27122.3.0.193 to 122.3.0.222122.3.0.22330
8122.3.0.224/27122.3.0.225 to 122.3.0.254122.3.0.25530
9122.3.1.0/27122.3.1.1 to 122.3.1.30122.3.1.3130
10122.3.1.32/27122.3.1.33 to 122.3.1.62122.3.1.6330
11122.3.1.64/27122.3.1.65 to 122.3.1.94122.3.1.9530
12122.3.1.96/27122.3.1.97 to 122.3.1.126122.3.1.12730
13122.3.1.128/27122.3.1.129 to 122.3.1.158122.3.1.15930
14122.3.1.160/27122.3.1.161 to 122.3.1.190122.3.1.19130
15122.3.1.192/27122.3.1.193 to 122.3.1.222122.3.1.22330
16122.3.1.224/27122.3.1.225 to 122.3.1.254122.3.1.25530
17122.3.2.0/27122.3.2.1 to 122.3.2.30122.3.2.3130
18122.3.2.32/27122.3.2.33 to 122.3.2.62122.3.2.6330
19122.3.2.64/27122.3.2.65 to 122.3.2.94122.3.2.9530
20122.3.2.96/27122.3.2.97 to 122.3.2.126122.3.2.12730
21122.3.2.128/27122.3.2.129 to 122.3.2.158122.3.2.15930
22122.3.2.160/27122.3.2.161 to 122.3.2.190122.3.2.19130
23122.3.2.192/27122.3.2.193 to 122.3.2.222122.3.2.22330
24122.3.2.224/27122.3.2.225 to 122.3.2.254122.3.2.25530
25122.3.3.0/27122.3.3.1 to 122.3.3.30122.3.3.3130
26122.3.3.32/27122.3.3.33 to 122.3.3.62122.3.3.6330
27122.3.3.64/27122.3.3.65 to 122.3.3.94122.3.3.9530
28122.3.3.96/27122.3.3.97 to 122.3.3.126122.3.3.12730
29122.3.3.128/27122.3.3.129 to 122.3.3.158122.3.3.15930
30122.3.3.160/27122.3.3.161 to 122.3.3.190122.3.3.19130
31122.3.3.192/27122.3.3.193 to 122.3.3.222122.3.3.22330
32122.3.3.224/27122.3.3.225 to 122.3.3.254122.3.3.25530
33122.3.4.0/27122.3.4.1 to 122.3.4.30122.3.4.3130
34122.3.4.32/27122.3.4.33 to 122.3.4.62122.3.4.6330
35122.3.4.64/27122.3.4.65 to 122.3.4.94122.3.4.9530
36122.3.4.96/27122.3.4.97 to 122.3.4.126122.3.4.12730
37122.3.4.128/27122.3.4.129 to 122.3.4.158122.3.4.15930
38122.3.4.160/27122.3.4.161 to 122.3.4.190122.3.4.19130
39122.3.4.192/27122.3.4.193 to 122.3.4.222122.3.4.22330
40122.3.4.224/27122.3.4.225 to 122.3.4.254122.3.4.25530
41122.3.5.0/27122.3.5.1 to 122.3.5.30122.3.5.3130
42122.3.5.32/27122.3.5.33 to 122.3.5.62122.3.5.6330
43122.3.5.64/27122.3.5.65 to 122.3.5.94122.3.5.9530
44122.3.5.96/27122.3.5.97 to 122.3.5.126122.3.5.12730
45122.3.5.128/27122.3.5.129 to 122.3.5.158122.3.5.15930
46122.3.5.160/27122.3.5.161 to 122.3.5.190122.3.5.19130
47122.3.5.192/27122.3.5.193 to 122.3.5.222122.3.5.22330
48122.3.5.224/27122.3.5.225 to 122.3.5.254122.3.5.25530
49122.3.6.0/27122.3.6.1 to 122.3.6.30122.3.6.3130
50122.3.6.32/27122.3.6.33 to 122.3.6.62122.3.6.6330
51122.3.6.64/27122.3.6.65 to 122.3.6.94122.3.6.9530
52122.3.6.96/27122.3.6.97 to 122.3.6.126122.3.6.12730
53122.3.6.128/27122.3.6.129 to 122.3.6.158122.3.6.15930
54122.3.6.160/27122.3.6.161 to 122.3.6.190122.3.6.19130
55122.3.6.192/27122.3.6.193 to 122.3.6.222122.3.6.22330
56122.3.6.224/27122.3.6.225 to 122.3.6.254122.3.6.25530
57122.3.7.0/27122.3.7.1 to 122.3.7.30122.3.7.3130
58122.3.7.32/27122.3.7.33 to 122.3.7.62122.3.7.6330
59122.3.7.64/27122.3.7.65 to 122.3.7.94122.3.7.9530
60122.3.7.96/27122.3.7.97 to 122.3.7.126122.3.7.12730
61122.3.7.128/27122.3.7.129 to 122.3.7.158122.3.7.15930
62122.3.7.160/27122.3.7.161 to 122.3.7.190122.3.7.19130
63122.3.7.192/27122.3.7.193 to 122.3.7.222122.3.7.22330
64122.3.7.224/27122.3.7.225 to 122.3.7.254122.3.7.25530
65122.3.8.0/27122.3.8.1 to 122.3.8.30122.3.8.3130
66122.3.8.32/27122.3.8.33 to 122.3.8.62122.3.8.6330
67122.3.8.64/27122.3.8.65 to 122.3.8.94122.3.8.9530
68122.3.8.96/27122.3.8.97 to 122.3.8.126122.3.8.12730
69122.3.8.128/27122.3.8.129 to 122.3.8.158122.3.8.15930
70122.3.8.160/27122.3.8.161 to 122.3.8.190122.3.8.19130
71122.3.8.192/27122.3.8.193 to 122.3.8.222122.3.8.22330
72122.3.8.224/27122.3.8.225 to 122.3.8.254122.3.8.25530
73122.3.9.0/27122.3.9.1 to 122.3.9.30122.3.9.3130
74122.3.9.32/27122.3.9.33 to 122.3.9.62122.3.9.6330
75122.3.9.64/27122.3.9.65 to 122.3.9.94122.3.9.9530
76122.3.9.96/27122.3.9.97 to 122.3.9.126122.3.9.12730
77122.3.9.128/27122.3.9.129 to 122.3.9.158122.3.9.15930
78122.3.9.160/27122.3.9.161 to 122.3.9.190122.3.9.19130
79122.3.9.192/27122.3.9.193 to 122.3.9.222122.3.9.22330
80122.3.9.224/27122.3.9.225 to 122.3.9.254122.3.9.25530
81122.3.10.0/27122.3.10.1 to 122.3.10.30122.3.10.3130
82122.3.10.32/27122.3.10.33 to 122.3.10.62122.3.10.6330
83122.3.10.64/27122.3.10.65 to 122.3.10.94122.3.10.9530
84122.3.10.96/27122.3.10.97 to 122.3.10.126122.3.10.12730
85122.3.10.128/27122.3.10.129 to 122.3.10.158122.3.10.15930
86122.3.10.160/27122.3.10.161 to 122.3.10.190122.3.10.19130
87122.3.10.192/27122.3.10.193 to 122.3.10.222122.3.10.22330
88122.3.10.224/27122.3.10.225 to 122.3.10.254122.3.10.25530
89122.3.11.0/27122.3.11.1 to 122.3.11.30122.3.11.3130
90122.3.11.32/27122.3.11.33 to 122.3.11.62122.3.11.6330
91122.3.11.64/27122.3.11.65 to 122.3.11.94122.3.11.9530
92122.3.11.96/27122.3.11.97 to 122.3.11.126122.3.11.12730
93122.3.11.128/27122.3.11.129 to 122.3.11.158122.3.11.15930
94122.3.11.160/27122.3.11.161 to 122.3.11.190122.3.11.19130
95122.3.11.192/27122.3.11.193 to 122.3.11.222122.3.11.22330
96122.3.11.224/27122.3.11.225 to 122.3.11.254122.3.11.25530
97122.3.12.0/27122.3.12.1 to 122.3.12.30122.3.12.3130
98122.3.12.32/27122.3.12.33 to 122.3.12.62122.3.12.6330
99122.3.12.64/27122.3.12.65 to 122.3.12.94122.3.12.9530
100122.3.12.96/27122.3.12.97 to 122.3.12.126122.3.12.12730
101122.3.12.128/27122.3.12.129 to 122.3.12.158122.3.12.15930
102122.3.12.160/27122.3.12.161 to 122.3.12.190122.3.12.19130
103122.3.12.192/27122.3.12.193 to 122.3.12.222122.3.12.22330
104122.3.12.224/27122.3.12.225 to 122.3.12.254122.3.12.25530
105122.3.13.0/27122.3.13.1 to 122.3.13.30122.3.13.3130
106122.3.13.32/27122.3.13.33 to 122.3.13.62122.3.13.6330
107122.3.13.64/27122.3.13.65 to 122.3.13.94122.3.13.9530
108122.3.13.96/27122.3.13.97 to 122.3.13.126122.3.13.12730
109122.3.13.128/27122.3.13.129 to 122.3.13.158122.3.13.15930
110122.3.13.160/27122.3.13.161 to 122.3.13.190122.3.13.19130
111122.3.13.192/27122.3.13.193 to 122.3.13.222122.3.13.22330
112122.3.13.224/27122.3.13.225 to 122.3.13.254122.3.13.25530
113122.3.14.0/27122.3.14.1 to 122.3.14.30122.3.14.3130
114122.3.14.32/27122.3.14.33 to 122.3.14.62122.3.14.6330
115122.3.14.64/27122.3.14.65 to 122.3.14.94122.3.14.9530
116122.3.14.96/27122.3.14.97 to 122.3.14.126122.3.14.12730
117122.3.14.128/27122.3.14.129 to 122.3.14.158122.3.14.15930
118122.3.14.160/27122.3.14.161 to 122.3.14.190122.3.14.19130
119122.3.14.192/27122.3.14.193 to 122.3.14.222122.3.14.22330
120122.3.14.224/27122.3.14.225 to 122.3.14.254122.3.14.25530
121122.3.15.0/27122.3.15.1 to 122.3.15.30122.3.15.3130
122122.3.15.32/27122.3.15.33 to 122.3.15.62122.3.15.6330
123122.3.15.64/27122.3.15.65 to 122.3.15.94122.3.15.9530
124122.3.15.96/27122.3.15.97 to 122.3.15.126122.3.15.12730
125122.3.15.128/27122.3.15.129 to 122.3.15.158122.3.15.15930
126122.3.15.160/27122.3.15.161 to 122.3.15.190122.3.15.19130
127122.3.15.192/27122.3.15.193 to 122.3.15.222122.3.15.22330
128122.3.15.224/27122.3.15.225 to 122.3.15.254122.3.15.25530
129122.3.16.0/27122.3.16.1 to 122.3.16.30122.3.16.3130
130122.3.16.32/27122.3.16.33 to 122.3.16.62122.3.16.6330
131122.3.16.64/27122.3.16.65 to 122.3.16.94122.3.16.9530
132122.3.16.96/27122.3.16.97 to 122.3.16.126122.3.16.12730
133122.3.16.128/27122.3.16.129 to 122.3.16.158122.3.16.15930
134122.3.16.160/27122.3.16.161 to 122.3.16.190122.3.16.19130
135122.3.16.192/27122.3.16.193 to 122.3.16.222122.3.16.22330
136122.3.16.224/27122.3.16.225 to 122.3.16.254122.3.16.25530
137122.3.17.0/27122.3.17.1 to 122.3.17.30122.3.17.3130
138122.3.17.32/27122.3.17.33 to 122.3.17.62122.3.17.6330
139122.3.17.64/27122.3.17.65 to 122.3.17.94122.3.17.9530
140122.3.17.96/27122.3.17.97 to 122.3.17.126122.3.17.12730
141122.3.17.128/27122.3.17.129 to 122.3.17.158122.3.17.15930
142122.3.17.160/27122.3.17.161 to 122.3.17.190122.3.17.19130
143122.3.17.192/27122.3.17.193 to 122.3.17.222122.3.17.22330
144122.3.17.224/27122.3.17.225 to 122.3.17.254122.3.17.25530
145122.3.18.0/27122.3.18.1 to 122.3.18.30122.3.18.3130
146122.3.18.32/27122.3.18.33 to 122.3.18.62122.3.18.6330
147122.3.18.64/27122.3.18.65 to 122.3.18.94122.3.18.9530
148122.3.18.96/27122.3.18.97 to 122.3.18.126122.3.18.12730
149122.3.18.128/27122.3.18.129 to 122.3.18.158122.3.18.15930
150122.3.18.160/27122.3.18.161 to 122.3.18.190122.3.18.19130
151122.3.18.192/27122.3.18.193 to 122.3.18.222122.3.18.22330
152122.3.18.224/27122.3.18.225 to 122.3.18.254122.3.18.25530
153122.3.19.0/27122.3.19.1 to 122.3.19.30122.3.19.3130
154122.3.19.32/27122.3.19.33 to 122.3.19.62122.3.19.6330
155122.3.19.64/27122.3.19.65 to 122.3.19.94122.3.19.9530
156122.3.19.96/27122.3.19.97 to 122.3.19.126122.3.19.12730
157122.3.19.128/27122.3.19.129 to 122.3.19.158122.3.19.15930
158122.3.19.160/27122.3.19.161 to 122.3.19.190122.3.19.19130
159122.3.19.192/27122.3.19.193 to 122.3.19.222122.3.19.22330
160122.3.19.224/27122.3.19.225 to 122.3.19.254122.3.19.25530
161122.3.20.0/27122.3.20.1 to 122.3.20.30122.3.20.3130
162122.3.20.32/27122.3.20.33 to 122.3.20.62122.3.20.6330
163122.3.20.64/27122.3.20.65 to 122.3.20.94122.3.20.9530
164122.3.20.96/27122.3.20.97 to 122.3.20.126122.3.20.12730
165122.3.20.128/27122.3.20.129 to 122.3.20.158122.3.20.15930
166122.3.20.160/27122.3.20.161 to 122.3.20.190122.3.20.19130
167122.3.20.192/27122.3.20.193 to 122.3.20.222122.3.20.22330
168122.3.20.224/27122.3.20.225 to 122.3.20.254122.3.20.25530
169122.3.21.0/27122.3.21.1 to 122.3.21.30122.3.21.3130
170122.3.21.32/27122.3.21.33 to 122.3.21.62122.3.21.6330
171122.3.21.64/27122.3.21.65 to 122.3.21.94122.3.21.9530
172122.3.21.96/27122.3.21.97 to 122.3.21.126122.3.21.12730
173122.3.21.128/27122.3.21.129 to 122.3.21.158122.3.21.15930
174122.3.21.160/27122.3.21.161 to 122.3.21.190122.3.21.19130
175122.3.21.192/27122.3.21.193 to 122.3.21.222122.3.21.22330
176122.3.21.224/27122.3.21.225 to 122.3.21.254122.3.21.25530
177122.3.22.0/27122.3.22.1 to 122.3.22.30122.3.22.3130
178122.3.22.32/27122.3.22.33 to 122.3.22.62122.3.22.6330
179122.3.22.64/27122.3.22.65 to 122.3.22.94122.3.22.9530
180122.3.22.96/27122.3.22.97 to 122.3.22.126122.3.22.12730
181122.3.22.128/27122.3.22.129 to 122.3.22.158122.3.22.15930
182122.3.22.160/27122.3.22.161 to 122.3.22.190122.3.22.19130
183122.3.22.192/27122.3.22.193 to 122.3.22.222122.3.22.22330
184122.3.22.224/27122.3.22.225 to 122.3.22.254122.3.22.25530
185122.3.23.0/27122.3.23.1 to 122.3.23.30122.3.23.3130
186122.3.23.32/27122.3.23.33 to 122.3.23.62122.3.23.6330
187122.3.23.64/27122.3.23.65 to 122.3.23.94122.3.23.9530
188122.3.23.96/27122.3.23.97 to 122.3.23.126122.3.23.12730
189122.3.23.128/27122.3.23.129 to 122.3.23.158122.3.23.15930
190122.3.23.160/27122.3.23.161 to 122.3.23.190122.3.23.19130
191122.3.23.192/27122.3.23.193 to 122.3.23.222122.3.23.22330
192122.3.23.224/27122.3.23.225 to 122.3.23.254122.3.23.25530
193122.3.24.0/27122.3.24.1 to 122.3.24.30122.3.24.3130
194122.3.24.32/27122.3.24.33 to 122.3.24.62122.3.24.6330
195122.3.24.64/27122.3.24.65 to 122.3.24.94122.3.24.9530
196122.3.24.96/27122.3.24.97 to 122.3.24.126122.3.24.12730
197122.3.24.128/27122.3.24.129 to 122.3.24.158122.3.24.15930
198122.3.24.160/27122.3.24.161 to 122.3.24.190122.3.24.19130
199122.3.24.192/27122.3.24.193 to 122.3.24.222122.3.24.22330
200122.3.24.224/27122.3.24.225 to 122.3.24.254122.3.24.25530
201122.3.25.0/27122.3.25.1 to 122.3.25.30122.3.25.3130
202122.3.25.32/27122.3.25.33 to 122.3.25.62122.3.25.6330
203122.3.25.64/27122.3.25.65 to 122.3.25.94122.3.25.9530
204122.3.25.96/27122.3.25.97 to 122.3.25.126122.3.25.12730
205122.3.25.128/27122.3.25.129 to 122.3.25.158122.3.25.15930
206122.3.25.160/27122.3.25.161 to 122.3.25.190122.3.25.19130
207122.3.25.192/27122.3.25.193 to 122.3.25.222122.3.25.22330
208122.3.25.224/27122.3.25.225 to 122.3.25.254122.3.25.25530
209122.3.26.0/27122.3.26.1 to 122.3.26.30122.3.26.3130
210122.3.26.32/27122.3.26.33 to 122.3.26.62122.3.26.6330
211122.3.26.64/27122.3.26.65 to 122.3.26.94122.3.26.9530
212122.3.26.96/27122.3.26.97 to 122.3.26.126122.3.26.12730
213122.3.26.128/27122.3.26.129 to 122.3.26.158122.3.26.15930
214122.3.26.160/27122.3.26.161 to 122.3.26.190122.3.26.19130
215122.3.26.192/27122.3.26.193 to 122.3.26.222122.3.26.22330
216122.3.26.224/27122.3.26.225 to 122.3.26.254122.3.26.25530
217122.3.27.0/27122.3.27.1 to 122.3.27.30122.3.27.3130
218122.3.27.32/27122.3.27.33 to 122.3.27.62122.3.27.6330
219122.3.27.64/27122.3.27.65 to 122.3.27.94122.3.27.9530
220122.3.27.96/27122.3.27.97 to 122.3.27.126122.3.27.12730
221122.3.27.128/27122.3.27.129 to 122.3.27.158122.3.27.15930
222122.3.27.160/27122.3.27.161 to 122.3.27.190122.3.27.19130
223122.3.27.192/27122.3.27.193 to 122.3.27.222122.3.27.22330
224122.3.27.224/27122.3.27.225 to 122.3.27.254122.3.27.25530
225122.3.28.0/27122.3.28.1 to 122.3.28.30122.3.28.3130
226122.3.28.32/27122.3.28.33 to 122.3.28.62122.3.28.6330
227122.3.28.64/27122.3.28.65 to 122.3.28.94122.3.28.9530
228122.3.28.96/27122.3.28.97 to 122.3.28.126122.3.28.12730
229122.3.28.128/27122.3.28.129 to 122.3.28.158122.3.28.15930
230122.3.28.160/27122.3.28.161 to 122.3.28.190122.3.28.19130
231122.3.28.192/27122.3.28.193 to 122.3.28.222122.3.28.22330
232122.3.28.224/27122.3.28.225 to 122.3.28.254122.3.28.25530
233122.3.29.0/27122.3.29.1 to 122.3.29.30122.3.29.3130
234122.3.29.32/27122.3.29.33 to 122.3.29.62122.3.29.6330
235122.3.29.64/27122.3.29.65 to 122.3.29.94122.3.29.9530
236122.3.29.96/27122.3.29.97 to 122.3.29.126122.3.29.12730
237122.3.29.128/27122.3.29.129 to 122.3.29.158122.3.29.15930
238122.3.29.160/27122.3.29.161 to 122.3.29.190122.3.29.19130
239122.3.29.192/27122.3.29.193 to 122.3.29.222122.3.29.22330
240122.3.29.224/27122.3.29.225 to 122.3.29.254122.3.29.25530
241122.3.30.0/27122.3.30.1 to 122.3.30.30122.3.30.3130
242122.3.30.32/27122.3.30.33 to 122.3.30.62122.3.30.6330
243122.3.30.64/27122.3.30.65 to 122.3.30.94122.3.30.9530
244122.3.30.96/27122.3.30.97 to 122.3.30.126122.3.30.12730
245122.3.30.128/27122.3.30.129 to 122.3.30.158122.3.30.15930
246122.3.30.160/27122.3.30.161 to 122.3.30.190122.3.30.19130
247122.3.30.192/27122.3.30.193 to 122.3.30.222122.3.30.22330
248122.3.30.224/27122.3.30.225 to 122.3.30.254122.3.30.25530
249122.3.31.0/27122.3.31.1 to 122.3.31.30122.3.31.3130
250122.3.31.32/27122.3.31.33 to 122.3.31.62122.3.31.6330
251122.3.31.64/27122.3.31.65 to 122.3.31.94122.3.31.9530
252122.3.31.96/27122.3.31.97 to 122.3.31.126122.3.31.12730
253122.3.31.128/27122.3.31.129 to 122.3.31.158122.3.31.15930
254122.3.31.160/27122.3.31.161 to 122.3.31.190122.3.31.19130
255122.3.31.192/27122.3.31.193 to 122.3.31.222122.3.31.22330
256122.3.31.224/27122.3.31.225 to 122.3.31.254122.3.31.25530

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.