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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.

Network129.3.0.0/19
Usable hosts8,190
Subnet mask255.255.224.0
Addresses8,192
Network address
129.3.0.0
Broadcast address
129.3.31.255
First usable
129.3.0.1
Last usable
129.3.31.254
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
B (default /16)
As numbers
Hex 81030000 · Integer 2164457472 to 2164465663
Reverse DNS zones
0.3.129.in-addr.arpa
1.3.129.in-addr.arpa
2.3.129.in-addr.arpa
3.3.129.in-addr.arpa
4.3.129.in-addr.arpa
5.3.129.in-addr.arpa
6.3.129.in-addr.arpa
7.3.129.in-addr.arpa
8.3.129.in-addr.arpa
9.3.129.in-addr.arpa
10.3.129.in-addr.arpa
11.3.129.in-addr.arpa
12.3.129.in-addr.arpa
13.3.129.in-addr.arpa
14.3.129.in-addr.arpa
15.3.129.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
Address10000001.00000011.00000000.00000000129.3.0.0
Subnet mask11111111.11111111.11100000.00000000255.255.224.0
Network10000001.00000011.00000000.00000000129.3.0.0
Broadcast10000001.00000011.00011111.11111111129.3.31.255
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)

129.3.0.0/19 makes 256 subnets of /27.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1129.3.0.0/27129.3.0.1 to 129.3.0.30129.3.0.3130
2129.3.0.32/27129.3.0.33 to 129.3.0.62129.3.0.6330
3129.3.0.64/27129.3.0.65 to 129.3.0.94129.3.0.9530
4129.3.0.96/27129.3.0.97 to 129.3.0.126129.3.0.12730
5129.3.0.128/27129.3.0.129 to 129.3.0.158129.3.0.15930
6129.3.0.160/27129.3.0.161 to 129.3.0.190129.3.0.19130
7129.3.0.192/27129.3.0.193 to 129.3.0.222129.3.0.22330
8129.3.0.224/27129.3.0.225 to 129.3.0.254129.3.0.25530
9129.3.1.0/27129.3.1.1 to 129.3.1.30129.3.1.3130
10129.3.1.32/27129.3.1.33 to 129.3.1.62129.3.1.6330
11129.3.1.64/27129.3.1.65 to 129.3.1.94129.3.1.9530
12129.3.1.96/27129.3.1.97 to 129.3.1.126129.3.1.12730
13129.3.1.128/27129.3.1.129 to 129.3.1.158129.3.1.15930
14129.3.1.160/27129.3.1.161 to 129.3.1.190129.3.1.19130
15129.3.1.192/27129.3.1.193 to 129.3.1.222129.3.1.22330
16129.3.1.224/27129.3.1.225 to 129.3.1.254129.3.1.25530
17129.3.2.0/27129.3.2.1 to 129.3.2.30129.3.2.3130
18129.3.2.32/27129.3.2.33 to 129.3.2.62129.3.2.6330
19129.3.2.64/27129.3.2.65 to 129.3.2.94129.3.2.9530
20129.3.2.96/27129.3.2.97 to 129.3.2.126129.3.2.12730
21129.3.2.128/27129.3.2.129 to 129.3.2.158129.3.2.15930
22129.3.2.160/27129.3.2.161 to 129.3.2.190129.3.2.19130
23129.3.2.192/27129.3.2.193 to 129.3.2.222129.3.2.22330
24129.3.2.224/27129.3.2.225 to 129.3.2.254129.3.2.25530
25129.3.3.0/27129.3.3.1 to 129.3.3.30129.3.3.3130
26129.3.3.32/27129.3.3.33 to 129.3.3.62129.3.3.6330
27129.3.3.64/27129.3.3.65 to 129.3.3.94129.3.3.9530
28129.3.3.96/27129.3.3.97 to 129.3.3.126129.3.3.12730
29129.3.3.128/27129.3.3.129 to 129.3.3.158129.3.3.15930
30129.3.3.160/27129.3.3.161 to 129.3.3.190129.3.3.19130
31129.3.3.192/27129.3.3.193 to 129.3.3.222129.3.3.22330
32129.3.3.224/27129.3.3.225 to 129.3.3.254129.3.3.25530
33129.3.4.0/27129.3.4.1 to 129.3.4.30129.3.4.3130
34129.3.4.32/27129.3.4.33 to 129.3.4.62129.3.4.6330
35129.3.4.64/27129.3.4.65 to 129.3.4.94129.3.4.9530
36129.3.4.96/27129.3.4.97 to 129.3.4.126129.3.4.12730
37129.3.4.128/27129.3.4.129 to 129.3.4.158129.3.4.15930
38129.3.4.160/27129.3.4.161 to 129.3.4.190129.3.4.19130
39129.3.4.192/27129.3.4.193 to 129.3.4.222129.3.4.22330
40129.3.4.224/27129.3.4.225 to 129.3.4.254129.3.4.25530
41129.3.5.0/27129.3.5.1 to 129.3.5.30129.3.5.3130
42129.3.5.32/27129.3.5.33 to 129.3.5.62129.3.5.6330
43129.3.5.64/27129.3.5.65 to 129.3.5.94129.3.5.9530
44129.3.5.96/27129.3.5.97 to 129.3.5.126129.3.5.12730
45129.3.5.128/27129.3.5.129 to 129.3.5.158129.3.5.15930
46129.3.5.160/27129.3.5.161 to 129.3.5.190129.3.5.19130
47129.3.5.192/27129.3.5.193 to 129.3.5.222129.3.5.22330
48129.3.5.224/27129.3.5.225 to 129.3.5.254129.3.5.25530
49129.3.6.0/27129.3.6.1 to 129.3.6.30129.3.6.3130
50129.3.6.32/27129.3.6.33 to 129.3.6.62129.3.6.6330
51129.3.6.64/27129.3.6.65 to 129.3.6.94129.3.6.9530
52129.3.6.96/27129.3.6.97 to 129.3.6.126129.3.6.12730
53129.3.6.128/27129.3.6.129 to 129.3.6.158129.3.6.15930
54129.3.6.160/27129.3.6.161 to 129.3.6.190129.3.6.19130
55129.3.6.192/27129.3.6.193 to 129.3.6.222129.3.6.22330
56129.3.6.224/27129.3.6.225 to 129.3.6.254129.3.6.25530
57129.3.7.0/27129.3.7.1 to 129.3.7.30129.3.7.3130
58129.3.7.32/27129.3.7.33 to 129.3.7.62129.3.7.6330
59129.3.7.64/27129.3.7.65 to 129.3.7.94129.3.7.9530
60129.3.7.96/27129.3.7.97 to 129.3.7.126129.3.7.12730
61129.3.7.128/27129.3.7.129 to 129.3.7.158129.3.7.15930
62129.3.7.160/27129.3.7.161 to 129.3.7.190129.3.7.19130
63129.3.7.192/27129.3.7.193 to 129.3.7.222129.3.7.22330
64129.3.7.224/27129.3.7.225 to 129.3.7.254129.3.7.25530
65129.3.8.0/27129.3.8.1 to 129.3.8.30129.3.8.3130
66129.3.8.32/27129.3.8.33 to 129.3.8.62129.3.8.6330
67129.3.8.64/27129.3.8.65 to 129.3.8.94129.3.8.9530
68129.3.8.96/27129.3.8.97 to 129.3.8.126129.3.8.12730
69129.3.8.128/27129.3.8.129 to 129.3.8.158129.3.8.15930
70129.3.8.160/27129.3.8.161 to 129.3.8.190129.3.8.19130
71129.3.8.192/27129.3.8.193 to 129.3.8.222129.3.8.22330
72129.3.8.224/27129.3.8.225 to 129.3.8.254129.3.8.25530
73129.3.9.0/27129.3.9.1 to 129.3.9.30129.3.9.3130
74129.3.9.32/27129.3.9.33 to 129.3.9.62129.3.9.6330
75129.3.9.64/27129.3.9.65 to 129.3.9.94129.3.9.9530
76129.3.9.96/27129.3.9.97 to 129.3.9.126129.3.9.12730
77129.3.9.128/27129.3.9.129 to 129.3.9.158129.3.9.15930
78129.3.9.160/27129.3.9.161 to 129.3.9.190129.3.9.19130
79129.3.9.192/27129.3.9.193 to 129.3.9.222129.3.9.22330
80129.3.9.224/27129.3.9.225 to 129.3.9.254129.3.9.25530
81129.3.10.0/27129.3.10.1 to 129.3.10.30129.3.10.3130
82129.3.10.32/27129.3.10.33 to 129.3.10.62129.3.10.6330
83129.3.10.64/27129.3.10.65 to 129.3.10.94129.3.10.9530
84129.3.10.96/27129.3.10.97 to 129.3.10.126129.3.10.12730
85129.3.10.128/27129.3.10.129 to 129.3.10.158129.3.10.15930
86129.3.10.160/27129.3.10.161 to 129.3.10.190129.3.10.19130
87129.3.10.192/27129.3.10.193 to 129.3.10.222129.3.10.22330
88129.3.10.224/27129.3.10.225 to 129.3.10.254129.3.10.25530
89129.3.11.0/27129.3.11.1 to 129.3.11.30129.3.11.3130
90129.3.11.32/27129.3.11.33 to 129.3.11.62129.3.11.6330
91129.3.11.64/27129.3.11.65 to 129.3.11.94129.3.11.9530
92129.3.11.96/27129.3.11.97 to 129.3.11.126129.3.11.12730
93129.3.11.128/27129.3.11.129 to 129.3.11.158129.3.11.15930
94129.3.11.160/27129.3.11.161 to 129.3.11.190129.3.11.19130
95129.3.11.192/27129.3.11.193 to 129.3.11.222129.3.11.22330
96129.3.11.224/27129.3.11.225 to 129.3.11.254129.3.11.25530
97129.3.12.0/27129.3.12.1 to 129.3.12.30129.3.12.3130
98129.3.12.32/27129.3.12.33 to 129.3.12.62129.3.12.6330
99129.3.12.64/27129.3.12.65 to 129.3.12.94129.3.12.9530
100129.3.12.96/27129.3.12.97 to 129.3.12.126129.3.12.12730
101129.3.12.128/27129.3.12.129 to 129.3.12.158129.3.12.15930
102129.3.12.160/27129.3.12.161 to 129.3.12.190129.3.12.19130
103129.3.12.192/27129.3.12.193 to 129.3.12.222129.3.12.22330
104129.3.12.224/27129.3.12.225 to 129.3.12.254129.3.12.25530
105129.3.13.0/27129.3.13.1 to 129.3.13.30129.3.13.3130
106129.3.13.32/27129.3.13.33 to 129.3.13.62129.3.13.6330
107129.3.13.64/27129.3.13.65 to 129.3.13.94129.3.13.9530
108129.3.13.96/27129.3.13.97 to 129.3.13.126129.3.13.12730
109129.3.13.128/27129.3.13.129 to 129.3.13.158129.3.13.15930
110129.3.13.160/27129.3.13.161 to 129.3.13.190129.3.13.19130
111129.3.13.192/27129.3.13.193 to 129.3.13.222129.3.13.22330
112129.3.13.224/27129.3.13.225 to 129.3.13.254129.3.13.25530
113129.3.14.0/27129.3.14.1 to 129.3.14.30129.3.14.3130
114129.3.14.32/27129.3.14.33 to 129.3.14.62129.3.14.6330
115129.3.14.64/27129.3.14.65 to 129.3.14.94129.3.14.9530
116129.3.14.96/27129.3.14.97 to 129.3.14.126129.3.14.12730
117129.3.14.128/27129.3.14.129 to 129.3.14.158129.3.14.15930
118129.3.14.160/27129.3.14.161 to 129.3.14.190129.3.14.19130
119129.3.14.192/27129.3.14.193 to 129.3.14.222129.3.14.22330
120129.3.14.224/27129.3.14.225 to 129.3.14.254129.3.14.25530
121129.3.15.0/27129.3.15.1 to 129.3.15.30129.3.15.3130
122129.3.15.32/27129.3.15.33 to 129.3.15.62129.3.15.6330
123129.3.15.64/27129.3.15.65 to 129.3.15.94129.3.15.9530
124129.3.15.96/27129.3.15.97 to 129.3.15.126129.3.15.12730
125129.3.15.128/27129.3.15.129 to 129.3.15.158129.3.15.15930
126129.3.15.160/27129.3.15.161 to 129.3.15.190129.3.15.19130
127129.3.15.192/27129.3.15.193 to 129.3.15.222129.3.15.22330
128129.3.15.224/27129.3.15.225 to 129.3.15.254129.3.15.25530
129129.3.16.0/27129.3.16.1 to 129.3.16.30129.3.16.3130
130129.3.16.32/27129.3.16.33 to 129.3.16.62129.3.16.6330
131129.3.16.64/27129.3.16.65 to 129.3.16.94129.3.16.9530
132129.3.16.96/27129.3.16.97 to 129.3.16.126129.3.16.12730
133129.3.16.128/27129.3.16.129 to 129.3.16.158129.3.16.15930
134129.3.16.160/27129.3.16.161 to 129.3.16.190129.3.16.19130
135129.3.16.192/27129.3.16.193 to 129.3.16.222129.3.16.22330
136129.3.16.224/27129.3.16.225 to 129.3.16.254129.3.16.25530
137129.3.17.0/27129.3.17.1 to 129.3.17.30129.3.17.3130
138129.3.17.32/27129.3.17.33 to 129.3.17.62129.3.17.6330
139129.3.17.64/27129.3.17.65 to 129.3.17.94129.3.17.9530
140129.3.17.96/27129.3.17.97 to 129.3.17.126129.3.17.12730
141129.3.17.128/27129.3.17.129 to 129.3.17.158129.3.17.15930
142129.3.17.160/27129.3.17.161 to 129.3.17.190129.3.17.19130
143129.3.17.192/27129.3.17.193 to 129.3.17.222129.3.17.22330
144129.3.17.224/27129.3.17.225 to 129.3.17.254129.3.17.25530
145129.3.18.0/27129.3.18.1 to 129.3.18.30129.3.18.3130
146129.3.18.32/27129.3.18.33 to 129.3.18.62129.3.18.6330
147129.3.18.64/27129.3.18.65 to 129.3.18.94129.3.18.9530
148129.3.18.96/27129.3.18.97 to 129.3.18.126129.3.18.12730
149129.3.18.128/27129.3.18.129 to 129.3.18.158129.3.18.15930
150129.3.18.160/27129.3.18.161 to 129.3.18.190129.3.18.19130
151129.3.18.192/27129.3.18.193 to 129.3.18.222129.3.18.22330
152129.3.18.224/27129.3.18.225 to 129.3.18.254129.3.18.25530
153129.3.19.0/27129.3.19.1 to 129.3.19.30129.3.19.3130
154129.3.19.32/27129.3.19.33 to 129.3.19.62129.3.19.6330
155129.3.19.64/27129.3.19.65 to 129.3.19.94129.3.19.9530
156129.3.19.96/27129.3.19.97 to 129.3.19.126129.3.19.12730
157129.3.19.128/27129.3.19.129 to 129.3.19.158129.3.19.15930
158129.3.19.160/27129.3.19.161 to 129.3.19.190129.3.19.19130
159129.3.19.192/27129.3.19.193 to 129.3.19.222129.3.19.22330
160129.3.19.224/27129.3.19.225 to 129.3.19.254129.3.19.25530
161129.3.20.0/27129.3.20.1 to 129.3.20.30129.3.20.3130
162129.3.20.32/27129.3.20.33 to 129.3.20.62129.3.20.6330
163129.3.20.64/27129.3.20.65 to 129.3.20.94129.3.20.9530
164129.3.20.96/27129.3.20.97 to 129.3.20.126129.3.20.12730
165129.3.20.128/27129.3.20.129 to 129.3.20.158129.3.20.15930
166129.3.20.160/27129.3.20.161 to 129.3.20.190129.3.20.19130
167129.3.20.192/27129.3.20.193 to 129.3.20.222129.3.20.22330
168129.3.20.224/27129.3.20.225 to 129.3.20.254129.3.20.25530
169129.3.21.0/27129.3.21.1 to 129.3.21.30129.3.21.3130
170129.3.21.32/27129.3.21.33 to 129.3.21.62129.3.21.6330
171129.3.21.64/27129.3.21.65 to 129.3.21.94129.3.21.9530
172129.3.21.96/27129.3.21.97 to 129.3.21.126129.3.21.12730
173129.3.21.128/27129.3.21.129 to 129.3.21.158129.3.21.15930
174129.3.21.160/27129.3.21.161 to 129.3.21.190129.3.21.19130
175129.3.21.192/27129.3.21.193 to 129.3.21.222129.3.21.22330
176129.3.21.224/27129.3.21.225 to 129.3.21.254129.3.21.25530
177129.3.22.0/27129.3.22.1 to 129.3.22.30129.3.22.3130
178129.3.22.32/27129.3.22.33 to 129.3.22.62129.3.22.6330
179129.3.22.64/27129.3.22.65 to 129.3.22.94129.3.22.9530
180129.3.22.96/27129.3.22.97 to 129.3.22.126129.3.22.12730
181129.3.22.128/27129.3.22.129 to 129.3.22.158129.3.22.15930
182129.3.22.160/27129.3.22.161 to 129.3.22.190129.3.22.19130
183129.3.22.192/27129.3.22.193 to 129.3.22.222129.3.22.22330
184129.3.22.224/27129.3.22.225 to 129.3.22.254129.3.22.25530
185129.3.23.0/27129.3.23.1 to 129.3.23.30129.3.23.3130
186129.3.23.32/27129.3.23.33 to 129.3.23.62129.3.23.6330
187129.3.23.64/27129.3.23.65 to 129.3.23.94129.3.23.9530
188129.3.23.96/27129.3.23.97 to 129.3.23.126129.3.23.12730
189129.3.23.128/27129.3.23.129 to 129.3.23.158129.3.23.15930
190129.3.23.160/27129.3.23.161 to 129.3.23.190129.3.23.19130
191129.3.23.192/27129.3.23.193 to 129.3.23.222129.3.23.22330
192129.3.23.224/27129.3.23.225 to 129.3.23.254129.3.23.25530
193129.3.24.0/27129.3.24.1 to 129.3.24.30129.3.24.3130
194129.3.24.32/27129.3.24.33 to 129.3.24.62129.3.24.6330
195129.3.24.64/27129.3.24.65 to 129.3.24.94129.3.24.9530
196129.3.24.96/27129.3.24.97 to 129.3.24.126129.3.24.12730
197129.3.24.128/27129.3.24.129 to 129.3.24.158129.3.24.15930
198129.3.24.160/27129.3.24.161 to 129.3.24.190129.3.24.19130
199129.3.24.192/27129.3.24.193 to 129.3.24.222129.3.24.22330
200129.3.24.224/27129.3.24.225 to 129.3.24.254129.3.24.25530
201129.3.25.0/27129.3.25.1 to 129.3.25.30129.3.25.3130
202129.3.25.32/27129.3.25.33 to 129.3.25.62129.3.25.6330
203129.3.25.64/27129.3.25.65 to 129.3.25.94129.3.25.9530
204129.3.25.96/27129.3.25.97 to 129.3.25.126129.3.25.12730
205129.3.25.128/27129.3.25.129 to 129.3.25.158129.3.25.15930
206129.3.25.160/27129.3.25.161 to 129.3.25.190129.3.25.19130
207129.3.25.192/27129.3.25.193 to 129.3.25.222129.3.25.22330
208129.3.25.224/27129.3.25.225 to 129.3.25.254129.3.25.25530
209129.3.26.0/27129.3.26.1 to 129.3.26.30129.3.26.3130
210129.3.26.32/27129.3.26.33 to 129.3.26.62129.3.26.6330
211129.3.26.64/27129.3.26.65 to 129.3.26.94129.3.26.9530
212129.3.26.96/27129.3.26.97 to 129.3.26.126129.3.26.12730
213129.3.26.128/27129.3.26.129 to 129.3.26.158129.3.26.15930
214129.3.26.160/27129.3.26.161 to 129.3.26.190129.3.26.19130
215129.3.26.192/27129.3.26.193 to 129.3.26.222129.3.26.22330
216129.3.26.224/27129.3.26.225 to 129.3.26.254129.3.26.25530
217129.3.27.0/27129.3.27.1 to 129.3.27.30129.3.27.3130
218129.3.27.32/27129.3.27.33 to 129.3.27.62129.3.27.6330
219129.3.27.64/27129.3.27.65 to 129.3.27.94129.3.27.9530
220129.3.27.96/27129.3.27.97 to 129.3.27.126129.3.27.12730
221129.3.27.128/27129.3.27.129 to 129.3.27.158129.3.27.15930
222129.3.27.160/27129.3.27.161 to 129.3.27.190129.3.27.19130
223129.3.27.192/27129.3.27.193 to 129.3.27.222129.3.27.22330
224129.3.27.224/27129.3.27.225 to 129.3.27.254129.3.27.25530
225129.3.28.0/27129.3.28.1 to 129.3.28.30129.3.28.3130
226129.3.28.32/27129.3.28.33 to 129.3.28.62129.3.28.6330
227129.3.28.64/27129.3.28.65 to 129.3.28.94129.3.28.9530
228129.3.28.96/27129.3.28.97 to 129.3.28.126129.3.28.12730
229129.3.28.128/27129.3.28.129 to 129.3.28.158129.3.28.15930
230129.3.28.160/27129.3.28.161 to 129.3.28.190129.3.28.19130
231129.3.28.192/27129.3.28.193 to 129.3.28.222129.3.28.22330
232129.3.28.224/27129.3.28.225 to 129.3.28.254129.3.28.25530
233129.3.29.0/27129.3.29.1 to 129.3.29.30129.3.29.3130
234129.3.29.32/27129.3.29.33 to 129.3.29.62129.3.29.6330
235129.3.29.64/27129.3.29.65 to 129.3.29.94129.3.29.9530
236129.3.29.96/27129.3.29.97 to 129.3.29.126129.3.29.12730
237129.3.29.128/27129.3.29.129 to 129.3.29.158129.3.29.15930
238129.3.29.160/27129.3.29.161 to 129.3.29.190129.3.29.19130
239129.3.29.192/27129.3.29.193 to 129.3.29.222129.3.29.22330
240129.3.29.224/27129.3.29.225 to 129.3.29.254129.3.29.25530
241129.3.30.0/27129.3.30.1 to 129.3.30.30129.3.30.3130
242129.3.30.32/27129.3.30.33 to 129.3.30.62129.3.30.6330
243129.3.30.64/27129.3.30.65 to 129.3.30.94129.3.30.9530
244129.3.30.96/27129.3.30.97 to 129.3.30.126129.3.30.12730
245129.3.30.128/27129.3.30.129 to 129.3.30.158129.3.30.15930
246129.3.30.160/27129.3.30.161 to 129.3.30.190129.3.30.19130
247129.3.30.192/27129.3.30.193 to 129.3.30.222129.3.30.22330
248129.3.30.224/27129.3.30.225 to 129.3.30.254129.3.30.25530
249129.3.31.0/27129.3.31.1 to 129.3.31.30129.3.31.3130
250129.3.31.32/27129.3.31.33 to 129.3.31.62129.3.31.6330
251129.3.31.64/27129.3.31.65 to 129.3.31.94129.3.31.9530
252129.3.31.96/27129.3.31.97 to 129.3.31.126129.3.31.12730
253129.3.31.128/27129.3.31.129 to 129.3.31.158129.3.31.15930
254129.3.31.160/27129.3.31.161 to 129.3.31.190129.3.31.19130
255129.3.31.192/27129.3.31.193 to 129.3.31.222129.3.31.22330
256129.3.31.224/27129.3.31.225 to 129.3.31.254129.3.31.25530

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.