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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.

Network129.26.0.0/19
Usable hosts8,190
Subnet mask255.255.224.0
Addresses8,192
Network address
129.26.0.0
Broadcast address
129.26.31.255
First usable
129.26.0.1
Last usable
129.26.31.254
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 811A0000 · Integer 2165964800 to 2165972991
Reverse DNS zones
0.26.129.in-addr.arpa
1.26.129.in-addr.arpa
2.26.129.in-addr.arpa
3.26.129.in-addr.arpa
4.26.129.in-addr.arpa
5.26.129.in-addr.arpa
6.26.129.in-addr.arpa
7.26.129.in-addr.arpa
8.26.129.in-addr.arpa
9.26.129.in-addr.arpa
10.26.129.in-addr.arpa
11.26.129.in-addr.arpa
12.26.129.in-addr.arpa
13.26.129.in-addr.arpa
14.26.129.in-addr.arpa
15.26.129.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
Address10000001.00011010.00000000.00000000129.26.0.0
Subnet mask11111111.11111111.11100000.00000000255.255.224.0
Network10000001.00011010.00000000.00000000129.26.0.0
Broadcast10000001.00011010.00011111.11111111129.26.31.255
Split into smaller subnets/28
/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)

129.26.0.0/19 makes 512 subnets of /28; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1129.26.0.0/28129.26.0.1 to 129.26.0.14129.26.0.1514
2129.26.0.16/28129.26.0.17 to 129.26.0.30129.26.0.3114
3129.26.0.32/28129.26.0.33 to 129.26.0.46129.26.0.4714
4129.26.0.48/28129.26.0.49 to 129.26.0.62129.26.0.6314
5129.26.0.64/28129.26.0.65 to 129.26.0.78129.26.0.7914
6129.26.0.80/28129.26.0.81 to 129.26.0.94129.26.0.9514
7129.26.0.96/28129.26.0.97 to 129.26.0.110129.26.0.11114
8129.26.0.112/28129.26.0.113 to 129.26.0.126129.26.0.12714
9129.26.0.128/28129.26.0.129 to 129.26.0.142129.26.0.14314
10129.26.0.144/28129.26.0.145 to 129.26.0.158129.26.0.15914
11129.26.0.160/28129.26.0.161 to 129.26.0.174129.26.0.17514
12129.26.0.176/28129.26.0.177 to 129.26.0.190129.26.0.19114
13129.26.0.192/28129.26.0.193 to 129.26.0.206129.26.0.20714
14129.26.0.208/28129.26.0.209 to 129.26.0.222129.26.0.22314
15129.26.0.224/28129.26.0.225 to 129.26.0.238129.26.0.23914
16129.26.0.240/28129.26.0.241 to 129.26.0.254129.26.0.25514
17129.26.1.0/28129.26.1.1 to 129.26.1.14129.26.1.1514
18129.26.1.16/28129.26.1.17 to 129.26.1.30129.26.1.3114
19129.26.1.32/28129.26.1.33 to 129.26.1.46129.26.1.4714
20129.26.1.48/28129.26.1.49 to 129.26.1.62129.26.1.6314
21129.26.1.64/28129.26.1.65 to 129.26.1.78129.26.1.7914
22129.26.1.80/28129.26.1.81 to 129.26.1.94129.26.1.9514
23129.26.1.96/28129.26.1.97 to 129.26.1.110129.26.1.11114
24129.26.1.112/28129.26.1.113 to 129.26.1.126129.26.1.12714
25129.26.1.128/28129.26.1.129 to 129.26.1.142129.26.1.14314
26129.26.1.144/28129.26.1.145 to 129.26.1.158129.26.1.15914
27129.26.1.160/28129.26.1.161 to 129.26.1.174129.26.1.17514
28129.26.1.176/28129.26.1.177 to 129.26.1.190129.26.1.19114
29129.26.1.192/28129.26.1.193 to 129.26.1.206129.26.1.20714
30129.26.1.208/28129.26.1.209 to 129.26.1.222129.26.1.22314
31129.26.1.224/28129.26.1.225 to 129.26.1.238129.26.1.23914
32129.26.1.240/28129.26.1.241 to 129.26.1.254129.26.1.25514
33129.26.2.0/28129.26.2.1 to 129.26.2.14129.26.2.1514
34129.26.2.16/28129.26.2.17 to 129.26.2.30129.26.2.3114
35129.26.2.32/28129.26.2.33 to 129.26.2.46129.26.2.4714
36129.26.2.48/28129.26.2.49 to 129.26.2.62129.26.2.6314
37129.26.2.64/28129.26.2.65 to 129.26.2.78129.26.2.7914
38129.26.2.80/28129.26.2.81 to 129.26.2.94129.26.2.9514
39129.26.2.96/28129.26.2.97 to 129.26.2.110129.26.2.11114
40129.26.2.112/28129.26.2.113 to 129.26.2.126129.26.2.12714
41129.26.2.128/28129.26.2.129 to 129.26.2.142129.26.2.14314
42129.26.2.144/28129.26.2.145 to 129.26.2.158129.26.2.15914
43129.26.2.160/28129.26.2.161 to 129.26.2.174129.26.2.17514
44129.26.2.176/28129.26.2.177 to 129.26.2.190129.26.2.19114
45129.26.2.192/28129.26.2.193 to 129.26.2.206129.26.2.20714
46129.26.2.208/28129.26.2.209 to 129.26.2.222129.26.2.22314
47129.26.2.224/28129.26.2.225 to 129.26.2.238129.26.2.23914
48129.26.2.240/28129.26.2.241 to 129.26.2.254129.26.2.25514
49129.26.3.0/28129.26.3.1 to 129.26.3.14129.26.3.1514
50129.26.3.16/28129.26.3.17 to 129.26.3.30129.26.3.3114
51129.26.3.32/28129.26.3.33 to 129.26.3.46129.26.3.4714
52129.26.3.48/28129.26.3.49 to 129.26.3.62129.26.3.6314
53129.26.3.64/28129.26.3.65 to 129.26.3.78129.26.3.7914
54129.26.3.80/28129.26.3.81 to 129.26.3.94129.26.3.9514
55129.26.3.96/28129.26.3.97 to 129.26.3.110129.26.3.11114
56129.26.3.112/28129.26.3.113 to 129.26.3.126129.26.3.12714
57129.26.3.128/28129.26.3.129 to 129.26.3.142129.26.3.14314
58129.26.3.144/28129.26.3.145 to 129.26.3.158129.26.3.15914
59129.26.3.160/28129.26.3.161 to 129.26.3.174129.26.3.17514
60129.26.3.176/28129.26.3.177 to 129.26.3.190129.26.3.19114
61129.26.3.192/28129.26.3.193 to 129.26.3.206129.26.3.20714
62129.26.3.208/28129.26.3.209 to 129.26.3.222129.26.3.22314
63129.26.3.224/28129.26.3.225 to 129.26.3.238129.26.3.23914
64129.26.3.240/28129.26.3.241 to 129.26.3.254129.26.3.25514
65129.26.4.0/28129.26.4.1 to 129.26.4.14129.26.4.1514
66129.26.4.16/28129.26.4.17 to 129.26.4.30129.26.4.3114
67129.26.4.32/28129.26.4.33 to 129.26.4.46129.26.4.4714
68129.26.4.48/28129.26.4.49 to 129.26.4.62129.26.4.6314
69129.26.4.64/28129.26.4.65 to 129.26.4.78129.26.4.7914
70129.26.4.80/28129.26.4.81 to 129.26.4.94129.26.4.9514
71129.26.4.96/28129.26.4.97 to 129.26.4.110129.26.4.11114
72129.26.4.112/28129.26.4.113 to 129.26.4.126129.26.4.12714
73129.26.4.128/28129.26.4.129 to 129.26.4.142129.26.4.14314
74129.26.4.144/28129.26.4.145 to 129.26.4.158129.26.4.15914
75129.26.4.160/28129.26.4.161 to 129.26.4.174129.26.4.17514
76129.26.4.176/28129.26.4.177 to 129.26.4.190129.26.4.19114
77129.26.4.192/28129.26.4.193 to 129.26.4.206129.26.4.20714
78129.26.4.208/28129.26.4.209 to 129.26.4.222129.26.4.22314
79129.26.4.224/28129.26.4.225 to 129.26.4.238129.26.4.23914
80129.26.4.240/28129.26.4.241 to 129.26.4.254129.26.4.25514
81129.26.5.0/28129.26.5.1 to 129.26.5.14129.26.5.1514
82129.26.5.16/28129.26.5.17 to 129.26.5.30129.26.5.3114
83129.26.5.32/28129.26.5.33 to 129.26.5.46129.26.5.4714
84129.26.5.48/28129.26.5.49 to 129.26.5.62129.26.5.6314
85129.26.5.64/28129.26.5.65 to 129.26.5.78129.26.5.7914
86129.26.5.80/28129.26.5.81 to 129.26.5.94129.26.5.9514
87129.26.5.96/28129.26.5.97 to 129.26.5.110129.26.5.11114
88129.26.5.112/28129.26.5.113 to 129.26.5.126129.26.5.12714
89129.26.5.128/28129.26.5.129 to 129.26.5.142129.26.5.14314
90129.26.5.144/28129.26.5.145 to 129.26.5.158129.26.5.15914
91129.26.5.160/28129.26.5.161 to 129.26.5.174129.26.5.17514
92129.26.5.176/28129.26.5.177 to 129.26.5.190129.26.5.19114
93129.26.5.192/28129.26.5.193 to 129.26.5.206129.26.5.20714
94129.26.5.208/28129.26.5.209 to 129.26.5.222129.26.5.22314
95129.26.5.224/28129.26.5.225 to 129.26.5.238129.26.5.23914
96129.26.5.240/28129.26.5.241 to 129.26.5.254129.26.5.25514
97129.26.6.0/28129.26.6.1 to 129.26.6.14129.26.6.1514
98129.26.6.16/28129.26.6.17 to 129.26.6.30129.26.6.3114
99129.26.6.32/28129.26.6.33 to 129.26.6.46129.26.6.4714
100129.26.6.48/28129.26.6.49 to 129.26.6.62129.26.6.6314
101129.26.6.64/28129.26.6.65 to 129.26.6.78129.26.6.7914
102129.26.6.80/28129.26.6.81 to 129.26.6.94129.26.6.9514
103129.26.6.96/28129.26.6.97 to 129.26.6.110129.26.6.11114
104129.26.6.112/28129.26.6.113 to 129.26.6.126129.26.6.12714
105129.26.6.128/28129.26.6.129 to 129.26.6.142129.26.6.14314
106129.26.6.144/28129.26.6.145 to 129.26.6.158129.26.6.15914
107129.26.6.160/28129.26.6.161 to 129.26.6.174129.26.6.17514
108129.26.6.176/28129.26.6.177 to 129.26.6.190129.26.6.19114
109129.26.6.192/28129.26.6.193 to 129.26.6.206129.26.6.20714
110129.26.6.208/28129.26.6.209 to 129.26.6.222129.26.6.22314
111129.26.6.224/28129.26.6.225 to 129.26.6.238129.26.6.23914
112129.26.6.240/28129.26.6.241 to 129.26.6.254129.26.6.25514
113129.26.7.0/28129.26.7.1 to 129.26.7.14129.26.7.1514
114129.26.7.16/28129.26.7.17 to 129.26.7.30129.26.7.3114
115129.26.7.32/28129.26.7.33 to 129.26.7.46129.26.7.4714
116129.26.7.48/28129.26.7.49 to 129.26.7.62129.26.7.6314
117129.26.7.64/28129.26.7.65 to 129.26.7.78129.26.7.7914
118129.26.7.80/28129.26.7.81 to 129.26.7.94129.26.7.9514
119129.26.7.96/28129.26.7.97 to 129.26.7.110129.26.7.11114
120129.26.7.112/28129.26.7.113 to 129.26.7.126129.26.7.12714
121129.26.7.128/28129.26.7.129 to 129.26.7.142129.26.7.14314
122129.26.7.144/28129.26.7.145 to 129.26.7.158129.26.7.15914
123129.26.7.160/28129.26.7.161 to 129.26.7.174129.26.7.17514
124129.26.7.176/28129.26.7.177 to 129.26.7.190129.26.7.19114
125129.26.7.192/28129.26.7.193 to 129.26.7.206129.26.7.20714
126129.26.7.208/28129.26.7.209 to 129.26.7.222129.26.7.22314
127129.26.7.224/28129.26.7.225 to 129.26.7.238129.26.7.23914
128129.26.7.240/28129.26.7.241 to 129.26.7.254129.26.7.25514
129129.26.8.0/28129.26.8.1 to 129.26.8.14129.26.8.1514
130129.26.8.16/28129.26.8.17 to 129.26.8.30129.26.8.3114
131129.26.8.32/28129.26.8.33 to 129.26.8.46129.26.8.4714
132129.26.8.48/28129.26.8.49 to 129.26.8.62129.26.8.6314
133129.26.8.64/28129.26.8.65 to 129.26.8.78129.26.8.7914
134129.26.8.80/28129.26.8.81 to 129.26.8.94129.26.8.9514
135129.26.8.96/28129.26.8.97 to 129.26.8.110129.26.8.11114
136129.26.8.112/28129.26.8.113 to 129.26.8.126129.26.8.12714
137129.26.8.128/28129.26.8.129 to 129.26.8.142129.26.8.14314
138129.26.8.144/28129.26.8.145 to 129.26.8.158129.26.8.15914
139129.26.8.160/28129.26.8.161 to 129.26.8.174129.26.8.17514
140129.26.8.176/28129.26.8.177 to 129.26.8.190129.26.8.19114
141129.26.8.192/28129.26.8.193 to 129.26.8.206129.26.8.20714
142129.26.8.208/28129.26.8.209 to 129.26.8.222129.26.8.22314
143129.26.8.224/28129.26.8.225 to 129.26.8.238129.26.8.23914
144129.26.8.240/28129.26.8.241 to 129.26.8.254129.26.8.25514
145129.26.9.0/28129.26.9.1 to 129.26.9.14129.26.9.1514
146129.26.9.16/28129.26.9.17 to 129.26.9.30129.26.9.3114
147129.26.9.32/28129.26.9.33 to 129.26.9.46129.26.9.4714
148129.26.9.48/28129.26.9.49 to 129.26.9.62129.26.9.6314
149129.26.9.64/28129.26.9.65 to 129.26.9.78129.26.9.7914
150129.26.9.80/28129.26.9.81 to 129.26.9.94129.26.9.9514
151129.26.9.96/28129.26.9.97 to 129.26.9.110129.26.9.11114
152129.26.9.112/28129.26.9.113 to 129.26.9.126129.26.9.12714
153129.26.9.128/28129.26.9.129 to 129.26.9.142129.26.9.14314
154129.26.9.144/28129.26.9.145 to 129.26.9.158129.26.9.15914
155129.26.9.160/28129.26.9.161 to 129.26.9.174129.26.9.17514
156129.26.9.176/28129.26.9.177 to 129.26.9.190129.26.9.19114
157129.26.9.192/28129.26.9.193 to 129.26.9.206129.26.9.20714
158129.26.9.208/28129.26.9.209 to 129.26.9.222129.26.9.22314
159129.26.9.224/28129.26.9.225 to 129.26.9.238129.26.9.23914
160129.26.9.240/28129.26.9.241 to 129.26.9.254129.26.9.25514
161129.26.10.0/28129.26.10.1 to 129.26.10.14129.26.10.1514
162129.26.10.16/28129.26.10.17 to 129.26.10.30129.26.10.3114
163129.26.10.32/28129.26.10.33 to 129.26.10.46129.26.10.4714
164129.26.10.48/28129.26.10.49 to 129.26.10.62129.26.10.6314
165129.26.10.64/28129.26.10.65 to 129.26.10.78129.26.10.7914
166129.26.10.80/28129.26.10.81 to 129.26.10.94129.26.10.9514
167129.26.10.96/28129.26.10.97 to 129.26.10.110129.26.10.11114
168129.26.10.112/28129.26.10.113 to 129.26.10.126129.26.10.12714
169129.26.10.128/28129.26.10.129 to 129.26.10.142129.26.10.14314
170129.26.10.144/28129.26.10.145 to 129.26.10.158129.26.10.15914
171129.26.10.160/28129.26.10.161 to 129.26.10.174129.26.10.17514
172129.26.10.176/28129.26.10.177 to 129.26.10.190129.26.10.19114
173129.26.10.192/28129.26.10.193 to 129.26.10.206129.26.10.20714
174129.26.10.208/28129.26.10.209 to 129.26.10.222129.26.10.22314
175129.26.10.224/28129.26.10.225 to 129.26.10.238129.26.10.23914
176129.26.10.240/28129.26.10.241 to 129.26.10.254129.26.10.25514
177129.26.11.0/28129.26.11.1 to 129.26.11.14129.26.11.1514
178129.26.11.16/28129.26.11.17 to 129.26.11.30129.26.11.3114
179129.26.11.32/28129.26.11.33 to 129.26.11.46129.26.11.4714
180129.26.11.48/28129.26.11.49 to 129.26.11.62129.26.11.6314
181129.26.11.64/28129.26.11.65 to 129.26.11.78129.26.11.7914
182129.26.11.80/28129.26.11.81 to 129.26.11.94129.26.11.9514
183129.26.11.96/28129.26.11.97 to 129.26.11.110129.26.11.11114
184129.26.11.112/28129.26.11.113 to 129.26.11.126129.26.11.12714
185129.26.11.128/28129.26.11.129 to 129.26.11.142129.26.11.14314
186129.26.11.144/28129.26.11.145 to 129.26.11.158129.26.11.15914
187129.26.11.160/28129.26.11.161 to 129.26.11.174129.26.11.17514
188129.26.11.176/28129.26.11.177 to 129.26.11.190129.26.11.19114
189129.26.11.192/28129.26.11.193 to 129.26.11.206129.26.11.20714
190129.26.11.208/28129.26.11.209 to 129.26.11.222129.26.11.22314
191129.26.11.224/28129.26.11.225 to 129.26.11.238129.26.11.23914
192129.26.11.240/28129.26.11.241 to 129.26.11.254129.26.11.25514
193129.26.12.0/28129.26.12.1 to 129.26.12.14129.26.12.1514
194129.26.12.16/28129.26.12.17 to 129.26.12.30129.26.12.3114
195129.26.12.32/28129.26.12.33 to 129.26.12.46129.26.12.4714
196129.26.12.48/28129.26.12.49 to 129.26.12.62129.26.12.6314
197129.26.12.64/28129.26.12.65 to 129.26.12.78129.26.12.7914
198129.26.12.80/28129.26.12.81 to 129.26.12.94129.26.12.9514
199129.26.12.96/28129.26.12.97 to 129.26.12.110129.26.12.11114
200129.26.12.112/28129.26.12.113 to 129.26.12.126129.26.12.12714
201129.26.12.128/28129.26.12.129 to 129.26.12.142129.26.12.14314
202129.26.12.144/28129.26.12.145 to 129.26.12.158129.26.12.15914
203129.26.12.160/28129.26.12.161 to 129.26.12.174129.26.12.17514
204129.26.12.176/28129.26.12.177 to 129.26.12.190129.26.12.19114
205129.26.12.192/28129.26.12.193 to 129.26.12.206129.26.12.20714
206129.26.12.208/28129.26.12.209 to 129.26.12.222129.26.12.22314
207129.26.12.224/28129.26.12.225 to 129.26.12.238129.26.12.23914
208129.26.12.240/28129.26.12.241 to 129.26.12.254129.26.12.25514
209129.26.13.0/28129.26.13.1 to 129.26.13.14129.26.13.1514
210129.26.13.16/28129.26.13.17 to 129.26.13.30129.26.13.3114
211129.26.13.32/28129.26.13.33 to 129.26.13.46129.26.13.4714
212129.26.13.48/28129.26.13.49 to 129.26.13.62129.26.13.6314
213129.26.13.64/28129.26.13.65 to 129.26.13.78129.26.13.7914
214129.26.13.80/28129.26.13.81 to 129.26.13.94129.26.13.9514
215129.26.13.96/28129.26.13.97 to 129.26.13.110129.26.13.11114
216129.26.13.112/28129.26.13.113 to 129.26.13.126129.26.13.12714
217129.26.13.128/28129.26.13.129 to 129.26.13.142129.26.13.14314
218129.26.13.144/28129.26.13.145 to 129.26.13.158129.26.13.15914
219129.26.13.160/28129.26.13.161 to 129.26.13.174129.26.13.17514
220129.26.13.176/28129.26.13.177 to 129.26.13.190129.26.13.19114
221129.26.13.192/28129.26.13.193 to 129.26.13.206129.26.13.20714
222129.26.13.208/28129.26.13.209 to 129.26.13.222129.26.13.22314
223129.26.13.224/28129.26.13.225 to 129.26.13.238129.26.13.23914
224129.26.13.240/28129.26.13.241 to 129.26.13.254129.26.13.25514
225129.26.14.0/28129.26.14.1 to 129.26.14.14129.26.14.1514
226129.26.14.16/28129.26.14.17 to 129.26.14.30129.26.14.3114
227129.26.14.32/28129.26.14.33 to 129.26.14.46129.26.14.4714
228129.26.14.48/28129.26.14.49 to 129.26.14.62129.26.14.6314
229129.26.14.64/28129.26.14.65 to 129.26.14.78129.26.14.7914
230129.26.14.80/28129.26.14.81 to 129.26.14.94129.26.14.9514
231129.26.14.96/28129.26.14.97 to 129.26.14.110129.26.14.11114
232129.26.14.112/28129.26.14.113 to 129.26.14.126129.26.14.12714
233129.26.14.128/28129.26.14.129 to 129.26.14.142129.26.14.14314
234129.26.14.144/28129.26.14.145 to 129.26.14.158129.26.14.15914
235129.26.14.160/28129.26.14.161 to 129.26.14.174129.26.14.17514
236129.26.14.176/28129.26.14.177 to 129.26.14.190129.26.14.19114
237129.26.14.192/28129.26.14.193 to 129.26.14.206129.26.14.20714
238129.26.14.208/28129.26.14.209 to 129.26.14.222129.26.14.22314
239129.26.14.224/28129.26.14.225 to 129.26.14.238129.26.14.23914
240129.26.14.240/28129.26.14.241 to 129.26.14.254129.26.14.25514
241129.26.15.0/28129.26.15.1 to 129.26.15.14129.26.15.1514
242129.26.15.16/28129.26.15.17 to 129.26.15.30129.26.15.3114
243129.26.15.32/28129.26.15.33 to 129.26.15.46129.26.15.4714
244129.26.15.48/28129.26.15.49 to 129.26.15.62129.26.15.6314
245129.26.15.64/28129.26.15.65 to 129.26.15.78129.26.15.7914
246129.26.15.80/28129.26.15.81 to 129.26.15.94129.26.15.9514
247129.26.15.96/28129.26.15.97 to 129.26.15.110129.26.15.11114
248129.26.15.112/28129.26.15.113 to 129.26.15.126129.26.15.12714
249129.26.15.128/28129.26.15.129 to 129.26.15.142129.26.15.14314
250129.26.15.144/28129.26.15.145 to 129.26.15.158129.26.15.15914
251129.26.15.160/28129.26.15.161 to 129.26.15.174129.26.15.17514
252129.26.15.176/28129.26.15.177 to 129.26.15.190129.26.15.19114
253129.26.15.192/28129.26.15.193 to 129.26.15.206129.26.15.20714
254129.26.15.208/28129.26.15.209 to 129.26.15.222129.26.15.22314
255129.26.15.224/28129.26.15.225 to 129.26.15.238129.26.15.23914
256129.26.15.240/28129.26.15.241 to 129.26.15.254129.26.15.25514

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.