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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.

Network138.34.0.0/17
Usable hosts32,766
Subnet mask255.255.128.0
Addresses32,768
Network address
138.34.0.0
Broadcast address
138.34.127.255
First usable
138.34.0.1
Last usable
138.34.127.254
Usable hosts
32,766 (32,768 less the network and broadcast addresses)
Subnet mask
255.255.128.0
Wildcard mask
0.0.127.255 (Cisco ACLs, OSPF)
Prefix length
/17
Type
Public public
Old class
B (default /16)
As numbers
Hex 8A220000 · Integer 2317484032 to 2317516799
Reverse DNS zones
0.34.138.in-addr.arpa
1.34.138.in-addr.arpa
2.34.138.in-addr.arpa
3.34.138.in-addr.arpa
4.34.138.in-addr.arpa
5.34.138.in-addr.arpa
6.34.138.in-addr.arpa
7.34.138.in-addr.arpa
8.34.138.in-addr.arpa
9.34.138.in-addr.arpa
10.34.138.in-addr.arpa
11.34.138.in-addr.arpa
12.34.138.in-addr.arpa
13.34.138.in-addr.arpa
14.34.138.in-addr.arpa
15.34.138.in-addr.arpa
and 112 more
/17 is not on a 8-bit boundary, so it takes 128 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10001010.00100010.00000000.00000000138.34.0.0
Subnet mask11111111.11111111.10000000.00000000255.255.128.0
Network10001010.00100010.00000000.00000000138.34.0.0
Broadcast10001010.00100010.01111111.11111111138.34.127.255
Split into smaller subnets/28
/18 (2)/19 (4)/20 (8)/21 (16)/22 (32)/23 (64)/24 (128)/25 (256)/26 (512)/27 (1,024)/28 (2,048)/29 (4,096)

138.34.0.0/17 makes 2,048 subnets of /28; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1138.34.0.0/28138.34.0.1 to 138.34.0.14138.34.0.1514
2138.34.0.16/28138.34.0.17 to 138.34.0.30138.34.0.3114
3138.34.0.32/28138.34.0.33 to 138.34.0.46138.34.0.4714
4138.34.0.48/28138.34.0.49 to 138.34.0.62138.34.0.6314
5138.34.0.64/28138.34.0.65 to 138.34.0.78138.34.0.7914
6138.34.0.80/28138.34.0.81 to 138.34.0.94138.34.0.9514
7138.34.0.96/28138.34.0.97 to 138.34.0.110138.34.0.11114
8138.34.0.112/28138.34.0.113 to 138.34.0.126138.34.0.12714
9138.34.0.128/28138.34.0.129 to 138.34.0.142138.34.0.14314
10138.34.0.144/28138.34.0.145 to 138.34.0.158138.34.0.15914
11138.34.0.160/28138.34.0.161 to 138.34.0.174138.34.0.17514
12138.34.0.176/28138.34.0.177 to 138.34.0.190138.34.0.19114
13138.34.0.192/28138.34.0.193 to 138.34.0.206138.34.0.20714
14138.34.0.208/28138.34.0.209 to 138.34.0.222138.34.0.22314
15138.34.0.224/28138.34.0.225 to 138.34.0.238138.34.0.23914
16138.34.0.240/28138.34.0.241 to 138.34.0.254138.34.0.25514
17138.34.1.0/28138.34.1.1 to 138.34.1.14138.34.1.1514
18138.34.1.16/28138.34.1.17 to 138.34.1.30138.34.1.3114
19138.34.1.32/28138.34.1.33 to 138.34.1.46138.34.1.4714
20138.34.1.48/28138.34.1.49 to 138.34.1.62138.34.1.6314
21138.34.1.64/28138.34.1.65 to 138.34.1.78138.34.1.7914
22138.34.1.80/28138.34.1.81 to 138.34.1.94138.34.1.9514
23138.34.1.96/28138.34.1.97 to 138.34.1.110138.34.1.11114
24138.34.1.112/28138.34.1.113 to 138.34.1.126138.34.1.12714
25138.34.1.128/28138.34.1.129 to 138.34.1.142138.34.1.14314
26138.34.1.144/28138.34.1.145 to 138.34.1.158138.34.1.15914
27138.34.1.160/28138.34.1.161 to 138.34.1.174138.34.1.17514
28138.34.1.176/28138.34.1.177 to 138.34.1.190138.34.1.19114
29138.34.1.192/28138.34.1.193 to 138.34.1.206138.34.1.20714
30138.34.1.208/28138.34.1.209 to 138.34.1.222138.34.1.22314
31138.34.1.224/28138.34.1.225 to 138.34.1.238138.34.1.23914
32138.34.1.240/28138.34.1.241 to 138.34.1.254138.34.1.25514
33138.34.2.0/28138.34.2.1 to 138.34.2.14138.34.2.1514
34138.34.2.16/28138.34.2.17 to 138.34.2.30138.34.2.3114
35138.34.2.32/28138.34.2.33 to 138.34.2.46138.34.2.4714
36138.34.2.48/28138.34.2.49 to 138.34.2.62138.34.2.6314
37138.34.2.64/28138.34.2.65 to 138.34.2.78138.34.2.7914
38138.34.2.80/28138.34.2.81 to 138.34.2.94138.34.2.9514
39138.34.2.96/28138.34.2.97 to 138.34.2.110138.34.2.11114
40138.34.2.112/28138.34.2.113 to 138.34.2.126138.34.2.12714
41138.34.2.128/28138.34.2.129 to 138.34.2.142138.34.2.14314
42138.34.2.144/28138.34.2.145 to 138.34.2.158138.34.2.15914
43138.34.2.160/28138.34.2.161 to 138.34.2.174138.34.2.17514
44138.34.2.176/28138.34.2.177 to 138.34.2.190138.34.2.19114
45138.34.2.192/28138.34.2.193 to 138.34.2.206138.34.2.20714
46138.34.2.208/28138.34.2.209 to 138.34.2.222138.34.2.22314
47138.34.2.224/28138.34.2.225 to 138.34.2.238138.34.2.23914
48138.34.2.240/28138.34.2.241 to 138.34.2.254138.34.2.25514
49138.34.3.0/28138.34.3.1 to 138.34.3.14138.34.3.1514
50138.34.3.16/28138.34.3.17 to 138.34.3.30138.34.3.3114
51138.34.3.32/28138.34.3.33 to 138.34.3.46138.34.3.4714
52138.34.3.48/28138.34.3.49 to 138.34.3.62138.34.3.6314
53138.34.3.64/28138.34.3.65 to 138.34.3.78138.34.3.7914
54138.34.3.80/28138.34.3.81 to 138.34.3.94138.34.3.9514
55138.34.3.96/28138.34.3.97 to 138.34.3.110138.34.3.11114
56138.34.3.112/28138.34.3.113 to 138.34.3.126138.34.3.12714
57138.34.3.128/28138.34.3.129 to 138.34.3.142138.34.3.14314
58138.34.3.144/28138.34.3.145 to 138.34.3.158138.34.3.15914
59138.34.3.160/28138.34.3.161 to 138.34.3.174138.34.3.17514
60138.34.3.176/28138.34.3.177 to 138.34.3.190138.34.3.19114
61138.34.3.192/28138.34.3.193 to 138.34.3.206138.34.3.20714
62138.34.3.208/28138.34.3.209 to 138.34.3.222138.34.3.22314
63138.34.3.224/28138.34.3.225 to 138.34.3.238138.34.3.23914
64138.34.3.240/28138.34.3.241 to 138.34.3.254138.34.3.25514
65138.34.4.0/28138.34.4.1 to 138.34.4.14138.34.4.1514
66138.34.4.16/28138.34.4.17 to 138.34.4.30138.34.4.3114
67138.34.4.32/28138.34.4.33 to 138.34.4.46138.34.4.4714
68138.34.4.48/28138.34.4.49 to 138.34.4.62138.34.4.6314
69138.34.4.64/28138.34.4.65 to 138.34.4.78138.34.4.7914
70138.34.4.80/28138.34.4.81 to 138.34.4.94138.34.4.9514
71138.34.4.96/28138.34.4.97 to 138.34.4.110138.34.4.11114
72138.34.4.112/28138.34.4.113 to 138.34.4.126138.34.4.12714
73138.34.4.128/28138.34.4.129 to 138.34.4.142138.34.4.14314
74138.34.4.144/28138.34.4.145 to 138.34.4.158138.34.4.15914
75138.34.4.160/28138.34.4.161 to 138.34.4.174138.34.4.17514
76138.34.4.176/28138.34.4.177 to 138.34.4.190138.34.4.19114
77138.34.4.192/28138.34.4.193 to 138.34.4.206138.34.4.20714
78138.34.4.208/28138.34.4.209 to 138.34.4.222138.34.4.22314
79138.34.4.224/28138.34.4.225 to 138.34.4.238138.34.4.23914
80138.34.4.240/28138.34.4.241 to 138.34.4.254138.34.4.25514
81138.34.5.0/28138.34.5.1 to 138.34.5.14138.34.5.1514
82138.34.5.16/28138.34.5.17 to 138.34.5.30138.34.5.3114
83138.34.5.32/28138.34.5.33 to 138.34.5.46138.34.5.4714
84138.34.5.48/28138.34.5.49 to 138.34.5.62138.34.5.6314
85138.34.5.64/28138.34.5.65 to 138.34.5.78138.34.5.7914
86138.34.5.80/28138.34.5.81 to 138.34.5.94138.34.5.9514
87138.34.5.96/28138.34.5.97 to 138.34.5.110138.34.5.11114
88138.34.5.112/28138.34.5.113 to 138.34.5.126138.34.5.12714
89138.34.5.128/28138.34.5.129 to 138.34.5.142138.34.5.14314
90138.34.5.144/28138.34.5.145 to 138.34.5.158138.34.5.15914
91138.34.5.160/28138.34.5.161 to 138.34.5.174138.34.5.17514
92138.34.5.176/28138.34.5.177 to 138.34.5.190138.34.5.19114
93138.34.5.192/28138.34.5.193 to 138.34.5.206138.34.5.20714
94138.34.5.208/28138.34.5.209 to 138.34.5.222138.34.5.22314
95138.34.5.224/28138.34.5.225 to 138.34.5.238138.34.5.23914
96138.34.5.240/28138.34.5.241 to 138.34.5.254138.34.5.25514
97138.34.6.0/28138.34.6.1 to 138.34.6.14138.34.6.1514
98138.34.6.16/28138.34.6.17 to 138.34.6.30138.34.6.3114
99138.34.6.32/28138.34.6.33 to 138.34.6.46138.34.6.4714
100138.34.6.48/28138.34.6.49 to 138.34.6.62138.34.6.6314
101138.34.6.64/28138.34.6.65 to 138.34.6.78138.34.6.7914
102138.34.6.80/28138.34.6.81 to 138.34.6.94138.34.6.9514
103138.34.6.96/28138.34.6.97 to 138.34.6.110138.34.6.11114
104138.34.6.112/28138.34.6.113 to 138.34.6.126138.34.6.12714
105138.34.6.128/28138.34.6.129 to 138.34.6.142138.34.6.14314
106138.34.6.144/28138.34.6.145 to 138.34.6.158138.34.6.15914
107138.34.6.160/28138.34.6.161 to 138.34.6.174138.34.6.17514
108138.34.6.176/28138.34.6.177 to 138.34.6.190138.34.6.19114
109138.34.6.192/28138.34.6.193 to 138.34.6.206138.34.6.20714
110138.34.6.208/28138.34.6.209 to 138.34.6.222138.34.6.22314
111138.34.6.224/28138.34.6.225 to 138.34.6.238138.34.6.23914
112138.34.6.240/28138.34.6.241 to 138.34.6.254138.34.6.25514
113138.34.7.0/28138.34.7.1 to 138.34.7.14138.34.7.1514
114138.34.7.16/28138.34.7.17 to 138.34.7.30138.34.7.3114
115138.34.7.32/28138.34.7.33 to 138.34.7.46138.34.7.4714
116138.34.7.48/28138.34.7.49 to 138.34.7.62138.34.7.6314
117138.34.7.64/28138.34.7.65 to 138.34.7.78138.34.7.7914
118138.34.7.80/28138.34.7.81 to 138.34.7.94138.34.7.9514
119138.34.7.96/28138.34.7.97 to 138.34.7.110138.34.7.11114
120138.34.7.112/28138.34.7.113 to 138.34.7.126138.34.7.12714
121138.34.7.128/28138.34.7.129 to 138.34.7.142138.34.7.14314
122138.34.7.144/28138.34.7.145 to 138.34.7.158138.34.7.15914
123138.34.7.160/28138.34.7.161 to 138.34.7.174138.34.7.17514
124138.34.7.176/28138.34.7.177 to 138.34.7.190138.34.7.19114
125138.34.7.192/28138.34.7.193 to 138.34.7.206138.34.7.20714
126138.34.7.208/28138.34.7.209 to 138.34.7.222138.34.7.22314
127138.34.7.224/28138.34.7.225 to 138.34.7.238138.34.7.23914
128138.34.7.240/28138.34.7.241 to 138.34.7.254138.34.7.25514
129138.34.8.0/28138.34.8.1 to 138.34.8.14138.34.8.1514
130138.34.8.16/28138.34.8.17 to 138.34.8.30138.34.8.3114
131138.34.8.32/28138.34.8.33 to 138.34.8.46138.34.8.4714
132138.34.8.48/28138.34.8.49 to 138.34.8.62138.34.8.6314
133138.34.8.64/28138.34.8.65 to 138.34.8.78138.34.8.7914
134138.34.8.80/28138.34.8.81 to 138.34.8.94138.34.8.9514
135138.34.8.96/28138.34.8.97 to 138.34.8.110138.34.8.11114
136138.34.8.112/28138.34.8.113 to 138.34.8.126138.34.8.12714
137138.34.8.128/28138.34.8.129 to 138.34.8.142138.34.8.14314
138138.34.8.144/28138.34.8.145 to 138.34.8.158138.34.8.15914
139138.34.8.160/28138.34.8.161 to 138.34.8.174138.34.8.17514
140138.34.8.176/28138.34.8.177 to 138.34.8.190138.34.8.19114
141138.34.8.192/28138.34.8.193 to 138.34.8.206138.34.8.20714
142138.34.8.208/28138.34.8.209 to 138.34.8.222138.34.8.22314
143138.34.8.224/28138.34.8.225 to 138.34.8.238138.34.8.23914
144138.34.8.240/28138.34.8.241 to 138.34.8.254138.34.8.25514
145138.34.9.0/28138.34.9.1 to 138.34.9.14138.34.9.1514
146138.34.9.16/28138.34.9.17 to 138.34.9.30138.34.9.3114
147138.34.9.32/28138.34.9.33 to 138.34.9.46138.34.9.4714
148138.34.9.48/28138.34.9.49 to 138.34.9.62138.34.9.6314
149138.34.9.64/28138.34.9.65 to 138.34.9.78138.34.9.7914
150138.34.9.80/28138.34.9.81 to 138.34.9.94138.34.9.9514
151138.34.9.96/28138.34.9.97 to 138.34.9.110138.34.9.11114
152138.34.9.112/28138.34.9.113 to 138.34.9.126138.34.9.12714
153138.34.9.128/28138.34.9.129 to 138.34.9.142138.34.9.14314
154138.34.9.144/28138.34.9.145 to 138.34.9.158138.34.9.15914
155138.34.9.160/28138.34.9.161 to 138.34.9.174138.34.9.17514
156138.34.9.176/28138.34.9.177 to 138.34.9.190138.34.9.19114
157138.34.9.192/28138.34.9.193 to 138.34.9.206138.34.9.20714
158138.34.9.208/28138.34.9.209 to 138.34.9.222138.34.9.22314
159138.34.9.224/28138.34.9.225 to 138.34.9.238138.34.9.23914
160138.34.9.240/28138.34.9.241 to 138.34.9.254138.34.9.25514
161138.34.10.0/28138.34.10.1 to 138.34.10.14138.34.10.1514
162138.34.10.16/28138.34.10.17 to 138.34.10.30138.34.10.3114
163138.34.10.32/28138.34.10.33 to 138.34.10.46138.34.10.4714
164138.34.10.48/28138.34.10.49 to 138.34.10.62138.34.10.6314
165138.34.10.64/28138.34.10.65 to 138.34.10.78138.34.10.7914
166138.34.10.80/28138.34.10.81 to 138.34.10.94138.34.10.9514
167138.34.10.96/28138.34.10.97 to 138.34.10.110138.34.10.11114
168138.34.10.112/28138.34.10.113 to 138.34.10.126138.34.10.12714
169138.34.10.128/28138.34.10.129 to 138.34.10.142138.34.10.14314
170138.34.10.144/28138.34.10.145 to 138.34.10.158138.34.10.15914
171138.34.10.160/28138.34.10.161 to 138.34.10.174138.34.10.17514
172138.34.10.176/28138.34.10.177 to 138.34.10.190138.34.10.19114
173138.34.10.192/28138.34.10.193 to 138.34.10.206138.34.10.20714
174138.34.10.208/28138.34.10.209 to 138.34.10.222138.34.10.22314
175138.34.10.224/28138.34.10.225 to 138.34.10.238138.34.10.23914
176138.34.10.240/28138.34.10.241 to 138.34.10.254138.34.10.25514
177138.34.11.0/28138.34.11.1 to 138.34.11.14138.34.11.1514
178138.34.11.16/28138.34.11.17 to 138.34.11.30138.34.11.3114
179138.34.11.32/28138.34.11.33 to 138.34.11.46138.34.11.4714
180138.34.11.48/28138.34.11.49 to 138.34.11.62138.34.11.6314
181138.34.11.64/28138.34.11.65 to 138.34.11.78138.34.11.7914
182138.34.11.80/28138.34.11.81 to 138.34.11.94138.34.11.9514
183138.34.11.96/28138.34.11.97 to 138.34.11.110138.34.11.11114
184138.34.11.112/28138.34.11.113 to 138.34.11.126138.34.11.12714
185138.34.11.128/28138.34.11.129 to 138.34.11.142138.34.11.14314
186138.34.11.144/28138.34.11.145 to 138.34.11.158138.34.11.15914
187138.34.11.160/28138.34.11.161 to 138.34.11.174138.34.11.17514
188138.34.11.176/28138.34.11.177 to 138.34.11.190138.34.11.19114
189138.34.11.192/28138.34.11.193 to 138.34.11.206138.34.11.20714
190138.34.11.208/28138.34.11.209 to 138.34.11.222138.34.11.22314
191138.34.11.224/28138.34.11.225 to 138.34.11.238138.34.11.23914
192138.34.11.240/28138.34.11.241 to 138.34.11.254138.34.11.25514
193138.34.12.0/28138.34.12.1 to 138.34.12.14138.34.12.1514
194138.34.12.16/28138.34.12.17 to 138.34.12.30138.34.12.3114
195138.34.12.32/28138.34.12.33 to 138.34.12.46138.34.12.4714
196138.34.12.48/28138.34.12.49 to 138.34.12.62138.34.12.6314
197138.34.12.64/28138.34.12.65 to 138.34.12.78138.34.12.7914
198138.34.12.80/28138.34.12.81 to 138.34.12.94138.34.12.9514
199138.34.12.96/28138.34.12.97 to 138.34.12.110138.34.12.11114
200138.34.12.112/28138.34.12.113 to 138.34.12.126138.34.12.12714
201138.34.12.128/28138.34.12.129 to 138.34.12.142138.34.12.14314
202138.34.12.144/28138.34.12.145 to 138.34.12.158138.34.12.15914
203138.34.12.160/28138.34.12.161 to 138.34.12.174138.34.12.17514
204138.34.12.176/28138.34.12.177 to 138.34.12.190138.34.12.19114
205138.34.12.192/28138.34.12.193 to 138.34.12.206138.34.12.20714
206138.34.12.208/28138.34.12.209 to 138.34.12.222138.34.12.22314
207138.34.12.224/28138.34.12.225 to 138.34.12.238138.34.12.23914
208138.34.12.240/28138.34.12.241 to 138.34.12.254138.34.12.25514
209138.34.13.0/28138.34.13.1 to 138.34.13.14138.34.13.1514
210138.34.13.16/28138.34.13.17 to 138.34.13.30138.34.13.3114
211138.34.13.32/28138.34.13.33 to 138.34.13.46138.34.13.4714
212138.34.13.48/28138.34.13.49 to 138.34.13.62138.34.13.6314
213138.34.13.64/28138.34.13.65 to 138.34.13.78138.34.13.7914
214138.34.13.80/28138.34.13.81 to 138.34.13.94138.34.13.9514
215138.34.13.96/28138.34.13.97 to 138.34.13.110138.34.13.11114
216138.34.13.112/28138.34.13.113 to 138.34.13.126138.34.13.12714
217138.34.13.128/28138.34.13.129 to 138.34.13.142138.34.13.14314
218138.34.13.144/28138.34.13.145 to 138.34.13.158138.34.13.15914
219138.34.13.160/28138.34.13.161 to 138.34.13.174138.34.13.17514
220138.34.13.176/28138.34.13.177 to 138.34.13.190138.34.13.19114
221138.34.13.192/28138.34.13.193 to 138.34.13.206138.34.13.20714
222138.34.13.208/28138.34.13.209 to 138.34.13.222138.34.13.22314
223138.34.13.224/28138.34.13.225 to 138.34.13.238138.34.13.23914
224138.34.13.240/28138.34.13.241 to 138.34.13.254138.34.13.25514
225138.34.14.0/28138.34.14.1 to 138.34.14.14138.34.14.1514
226138.34.14.16/28138.34.14.17 to 138.34.14.30138.34.14.3114
227138.34.14.32/28138.34.14.33 to 138.34.14.46138.34.14.4714
228138.34.14.48/28138.34.14.49 to 138.34.14.62138.34.14.6314
229138.34.14.64/28138.34.14.65 to 138.34.14.78138.34.14.7914
230138.34.14.80/28138.34.14.81 to 138.34.14.94138.34.14.9514
231138.34.14.96/28138.34.14.97 to 138.34.14.110138.34.14.11114
232138.34.14.112/28138.34.14.113 to 138.34.14.126138.34.14.12714
233138.34.14.128/28138.34.14.129 to 138.34.14.142138.34.14.14314
234138.34.14.144/28138.34.14.145 to 138.34.14.158138.34.14.15914
235138.34.14.160/28138.34.14.161 to 138.34.14.174138.34.14.17514
236138.34.14.176/28138.34.14.177 to 138.34.14.190138.34.14.19114
237138.34.14.192/28138.34.14.193 to 138.34.14.206138.34.14.20714
238138.34.14.208/28138.34.14.209 to 138.34.14.222138.34.14.22314
239138.34.14.224/28138.34.14.225 to 138.34.14.238138.34.14.23914
240138.34.14.240/28138.34.14.241 to 138.34.14.254138.34.14.25514
241138.34.15.0/28138.34.15.1 to 138.34.15.14138.34.15.1514
242138.34.15.16/28138.34.15.17 to 138.34.15.30138.34.15.3114
243138.34.15.32/28138.34.15.33 to 138.34.15.46138.34.15.4714
244138.34.15.48/28138.34.15.49 to 138.34.15.62138.34.15.6314
245138.34.15.64/28138.34.15.65 to 138.34.15.78138.34.15.7914
246138.34.15.80/28138.34.15.81 to 138.34.15.94138.34.15.9514
247138.34.15.96/28138.34.15.97 to 138.34.15.110138.34.15.11114
248138.34.15.112/28138.34.15.113 to 138.34.15.126138.34.15.12714
249138.34.15.128/28138.34.15.129 to 138.34.15.142138.34.15.14314
250138.34.15.144/28138.34.15.145 to 138.34.15.158138.34.15.15914
251138.34.15.160/28138.34.15.161 to 138.34.15.174138.34.15.17514
252138.34.15.176/28138.34.15.177 to 138.34.15.190138.34.15.19114
253138.34.15.192/28138.34.15.193 to 138.34.15.206138.34.15.20714
254138.34.15.208/28138.34.15.209 to 138.34.15.222138.34.15.22314
255138.34.15.224/28138.34.15.225 to 138.34.15.238138.34.15.23914
256138.34.15.240/28138.34.15.241 to 138.34.15.254138.34.15.25514

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.