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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.

Network138.78.0.0/17
Usable hosts32,766
Subnet mask255.255.128.0
Addresses32,768
Network address
138.78.0.0
Broadcast address
138.78.127.255
First usable
138.78.0.1
Last usable
138.78.127.254
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 8A4E0000 · Integer 2320367616 to 2320400383
Reverse DNS zones
0.78.138.in-addr.arpa
1.78.138.in-addr.arpa
2.78.138.in-addr.arpa
3.78.138.in-addr.arpa
4.78.138.in-addr.arpa
5.78.138.in-addr.arpa
6.78.138.in-addr.arpa
7.78.138.in-addr.arpa
8.78.138.in-addr.arpa
9.78.138.in-addr.arpa
10.78.138.in-addr.arpa
11.78.138.in-addr.arpa
12.78.138.in-addr.arpa
13.78.138.in-addr.arpa
14.78.138.in-addr.arpa
15.78.138.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
Address10001010.01001110.00000000.00000000138.78.0.0
Subnet mask11111111.11111111.10000000.00000000255.255.128.0
Network10001010.01001110.00000000.00000000138.78.0.0
Broadcast10001010.01001110.01111111.11111111138.78.127.255
Split into smaller subnets/29
/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)

138.78.0.0/17 makes 4,096 subnets of /29; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1138.78.0.0/29138.78.0.1 to 138.78.0.6138.78.0.76
2138.78.0.8/29138.78.0.9 to 138.78.0.14138.78.0.156
3138.78.0.16/29138.78.0.17 to 138.78.0.22138.78.0.236
4138.78.0.24/29138.78.0.25 to 138.78.0.30138.78.0.316
5138.78.0.32/29138.78.0.33 to 138.78.0.38138.78.0.396
6138.78.0.40/29138.78.0.41 to 138.78.0.46138.78.0.476
7138.78.0.48/29138.78.0.49 to 138.78.0.54138.78.0.556
8138.78.0.56/29138.78.0.57 to 138.78.0.62138.78.0.636
9138.78.0.64/29138.78.0.65 to 138.78.0.70138.78.0.716
10138.78.0.72/29138.78.0.73 to 138.78.0.78138.78.0.796
11138.78.0.80/29138.78.0.81 to 138.78.0.86138.78.0.876
12138.78.0.88/29138.78.0.89 to 138.78.0.94138.78.0.956
13138.78.0.96/29138.78.0.97 to 138.78.0.102138.78.0.1036
14138.78.0.104/29138.78.0.105 to 138.78.0.110138.78.0.1116
15138.78.0.112/29138.78.0.113 to 138.78.0.118138.78.0.1196
16138.78.0.120/29138.78.0.121 to 138.78.0.126138.78.0.1276
17138.78.0.128/29138.78.0.129 to 138.78.0.134138.78.0.1356
18138.78.0.136/29138.78.0.137 to 138.78.0.142138.78.0.1436
19138.78.0.144/29138.78.0.145 to 138.78.0.150138.78.0.1516
20138.78.0.152/29138.78.0.153 to 138.78.0.158138.78.0.1596
21138.78.0.160/29138.78.0.161 to 138.78.0.166138.78.0.1676
22138.78.0.168/29138.78.0.169 to 138.78.0.174138.78.0.1756
23138.78.0.176/29138.78.0.177 to 138.78.0.182138.78.0.1836
24138.78.0.184/29138.78.0.185 to 138.78.0.190138.78.0.1916
25138.78.0.192/29138.78.0.193 to 138.78.0.198138.78.0.1996
26138.78.0.200/29138.78.0.201 to 138.78.0.206138.78.0.2076
27138.78.0.208/29138.78.0.209 to 138.78.0.214138.78.0.2156
28138.78.0.216/29138.78.0.217 to 138.78.0.222138.78.0.2236
29138.78.0.224/29138.78.0.225 to 138.78.0.230138.78.0.2316
30138.78.0.232/29138.78.0.233 to 138.78.0.238138.78.0.2396
31138.78.0.240/29138.78.0.241 to 138.78.0.246138.78.0.2476
32138.78.0.248/29138.78.0.249 to 138.78.0.254138.78.0.2556
33138.78.1.0/29138.78.1.1 to 138.78.1.6138.78.1.76
34138.78.1.8/29138.78.1.9 to 138.78.1.14138.78.1.156
35138.78.1.16/29138.78.1.17 to 138.78.1.22138.78.1.236
36138.78.1.24/29138.78.1.25 to 138.78.1.30138.78.1.316
37138.78.1.32/29138.78.1.33 to 138.78.1.38138.78.1.396
38138.78.1.40/29138.78.1.41 to 138.78.1.46138.78.1.476
39138.78.1.48/29138.78.1.49 to 138.78.1.54138.78.1.556
40138.78.1.56/29138.78.1.57 to 138.78.1.62138.78.1.636
41138.78.1.64/29138.78.1.65 to 138.78.1.70138.78.1.716
42138.78.1.72/29138.78.1.73 to 138.78.1.78138.78.1.796
43138.78.1.80/29138.78.1.81 to 138.78.1.86138.78.1.876
44138.78.1.88/29138.78.1.89 to 138.78.1.94138.78.1.956
45138.78.1.96/29138.78.1.97 to 138.78.1.102138.78.1.1036
46138.78.1.104/29138.78.1.105 to 138.78.1.110138.78.1.1116
47138.78.1.112/29138.78.1.113 to 138.78.1.118138.78.1.1196
48138.78.1.120/29138.78.1.121 to 138.78.1.126138.78.1.1276
49138.78.1.128/29138.78.1.129 to 138.78.1.134138.78.1.1356
50138.78.1.136/29138.78.1.137 to 138.78.1.142138.78.1.1436
51138.78.1.144/29138.78.1.145 to 138.78.1.150138.78.1.1516
52138.78.1.152/29138.78.1.153 to 138.78.1.158138.78.1.1596
53138.78.1.160/29138.78.1.161 to 138.78.1.166138.78.1.1676
54138.78.1.168/29138.78.1.169 to 138.78.1.174138.78.1.1756
55138.78.1.176/29138.78.1.177 to 138.78.1.182138.78.1.1836
56138.78.1.184/29138.78.1.185 to 138.78.1.190138.78.1.1916
57138.78.1.192/29138.78.1.193 to 138.78.1.198138.78.1.1996
58138.78.1.200/29138.78.1.201 to 138.78.1.206138.78.1.2076
59138.78.1.208/29138.78.1.209 to 138.78.1.214138.78.1.2156
60138.78.1.216/29138.78.1.217 to 138.78.1.222138.78.1.2236
61138.78.1.224/29138.78.1.225 to 138.78.1.230138.78.1.2316
62138.78.1.232/29138.78.1.233 to 138.78.1.238138.78.1.2396
63138.78.1.240/29138.78.1.241 to 138.78.1.246138.78.1.2476
64138.78.1.248/29138.78.1.249 to 138.78.1.254138.78.1.2556
65138.78.2.0/29138.78.2.1 to 138.78.2.6138.78.2.76
66138.78.2.8/29138.78.2.9 to 138.78.2.14138.78.2.156
67138.78.2.16/29138.78.2.17 to 138.78.2.22138.78.2.236
68138.78.2.24/29138.78.2.25 to 138.78.2.30138.78.2.316
69138.78.2.32/29138.78.2.33 to 138.78.2.38138.78.2.396
70138.78.2.40/29138.78.2.41 to 138.78.2.46138.78.2.476
71138.78.2.48/29138.78.2.49 to 138.78.2.54138.78.2.556
72138.78.2.56/29138.78.2.57 to 138.78.2.62138.78.2.636
73138.78.2.64/29138.78.2.65 to 138.78.2.70138.78.2.716
74138.78.2.72/29138.78.2.73 to 138.78.2.78138.78.2.796
75138.78.2.80/29138.78.2.81 to 138.78.2.86138.78.2.876
76138.78.2.88/29138.78.2.89 to 138.78.2.94138.78.2.956
77138.78.2.96/29138.78.2.97 to 138.78.2.102138.78.2.1036
78138.78.2.104/29138.78.2.105 to 138.78.2.110138.78.2.1116
79138.78.2.112/29138.78.2.113 to 138.78.2.118138.78.2.1196
80138.78.2.120/29138.78.2.121 to 138.78.2.126138.78.2.1276
81138.78.2.128/29138.78.2.129 to 138.78.2.134138.78.2.1356
82138.78.2.136/29138.78.2.137 to 138.78.2.142138.78.2.1436
83138.78.2.144/29138.78.2.145 to 138.78.2.150138.78.2.1516
84138.78.2.152/29138.78.2.153 to 138.78.2.158138.78.2.1596
85138.78.2.160/29138.78.2.161 to 138.78.2.166138.78.2.1676
86138.78.2.168/29138.78.2.169 to 138.78.2.174138.78.2.1756
87138.78.2.176/29138.78.2.177 to 138.78.2.182138.78.2.1836
88138.78.2.184/29138.78.2.185 to 138.78.2.190138.78.2.1916
89138.78.2.192/29138.78.2.193 to 138.78.2.198138.78.2.1996
90138.78.2.200/29138.78.2.201 to 138.78.2.206138.78.2.2076
91138.78.2.208/29138.78.2.209 to 138.78.2.214138.78.2.2156
92138.78.2.216/29138.78.2.217 to 138.78.2.222138.78.2.2236
93138.78.2.224/29138.78.2.225 to 138.78.2.230138.78.2.2316
94138.78.2.232/29138.78.2.233 to 138.78.2.238138.78.2.2396
95138.78.2.240/29138.78.2.241 to 138.78.2.246138.78.2.2476
96138.78.2.248/29138.78.2.249 to 138.78.2.254138.78.2.2556
97138.78.3.0/29138.78.3.1 to 138.78.3.6138.78.3.76
98138.78.3.8/29138.78.3.9 to 138.78.3.14138.78.3.156
99138.78.3.16/29138.78.3.17 to 138.78.3.22138.78.3.236
100138.78.3.24/29138.78.3.25 to 138.78.3.30138.78.3.316
101138.78.3.32/29138.78.3.33 to 138.78.3.38138.78.3.396
102138.78.3.40/29138.78.3.41 to 138.78.3.46138.78.3.476
103138.78.3.48/29138.78.3.49 to 138.78.3.54138.78.3.556
104138.78.3.56/29138.78.3.57 to 138.78.3.62138.78.3.636
105138.78.3.64/29138.78.3.65 to 138.78.3.70138.78.3.716
106138.78.3.72/29138.78.3.73 to 138.78.3.78138.78.3.796
107138.78.3.80/29138.78.3.81 to 138.78.3.86138.78.3.876
108138.78.3.88/29138.78.3.89 to 138.78.3.94138.78.3.956
109138.78.3.96/29138.78.3.97 to 138.78.3.102138.78.3.1036
110138.78.3.104/29138.78.3.105 to 138.78.3.110138.78.3.1116
111138.78.3.112/29138.78.3.113 to 138.78.3.118138.78.3.1196
112138.78.3.120/29138.78.3.121 to 138.78.3.126138.78.3.1276
113138.78.3.128/29138.78.3.129 to 138.78.3.134138.78.3.1356
114138.78.3.136/29138.78.3.137 to 138.78.3.142138.78.3.1436
115138.78.3.144/29138.78.3.145 to 138.78.3.150138.78.3.1516
116138.78.3.152/29138.78.3.153 to 138.78.3.158138.78.3.1596
117138.78.3.160/29138.78.3.161 to 138.78.3.166138.78.3.1676
118138.78.3.168/29138.78.3.169 to 138.78.3.174138.78.3.1756
119138.78.3.176/29138.78.3.177 to 138.78.3.182138.78.3.1836
120138.78.3.184/29138.78.3.185 to 138.78.3.190138.78.3.1916
121138.78.3.192/29138.78.3.193 to 138.78.3.198138.78.3.1996
122138.78.3.200/29138.78.3.201 to 138.78.3.206138.78.3.2076
123138.78.3.208/29138.78.3.209 to 138.78.3.214138.78.3.2156
124138.78.3.216/29138.78.3.217 to 138.78.3.222138.78.3.2236
125138.78.3.224/29138.78.3.225 to 138.78.3.230138.78.3.2316
126138.78.3.232/29138.78.3.233 to 138.78.3.238138.78.3.2396
127138.78.3.240/29138.78.3.241 to 138.78.3.246138.78.3.2476
128138.78.3.248/29138.78.3.249 to 138.78.3.254138.78.3.2556
129138.78.4.0/29138.78.4.1 to 138.78.4.6138.78.4.76
130138.78.4.8/29138.78.4.9 to 138.78.4.14138.78.4.156
131138.78.4.16/29138.78.4.17 to 138.78.4.22138.78.4.236
132138.78.4.24/29138.78.4.25 to 138.78.4.30138.78.4.316
133138.78.4.32/29138.78.4.33 to 138.78.4.38138.78.4.396
134138.78.4.40/29138.78.4.41 to 138.78.4.46138.78.4.476
135138.78.4.48/29138.78.4.49 to 138.78.4.54138.78.4.556
136138.78.4.56/29138.78.4.57 to 138.78.4.62138.78.4.636
137138.78.4.64/29138.78.4.65 to 138.78.4.70138.78.4.716
138138.78.4.72/29138.78.4.73 to 138.78.4.78138.78.4.796
139138.78.4.80/29138.78.4.81 to 138.78.4.86138.78.4.876
140138.78.4.88/29138.78.4.89 to 138.78.4.94138.78.4.956
141138.78.4.96/29138.78.4.97 to 138.78.4.102138.78.4.1036
142138.78.4.104/29138.78.4.105 to 138.78.4.110138.78.4.1116
143138.78.4.112/29138.78.4.113 to 138.78.4.118138.78.4.1196
144138.78.4.120/29138.78.4.121 to 138.78.4.126138.78.4.1276
145138.78.4.128/29138.78.4.129 to 138.78.4.134138.78.4.1356
146138.78.4.136/29138.78.4.137 to 138.78.4.142138.78.4.1436
147138.78.4.144/29138.78.4.145 to 138.78.4.150138.78.4.1516
148138.78.4.152/29138.78.4.153 to 138.78.4.158138.78.4.1596
149138.78.4.160/29138.78.4.161 to 138.78.4.166138.78.4.1676
150138.78.4.168/29138.78.4.169 to 138.78.4.174138.78.4.1756
151138.78.4.176/29138.78.4.177 to 138.78.4.182138.78.4.1836
152138.78.4.184/29138.78.4.185 to 138.78.4.190138.78.4.1916
153138.78.4.192/29138.78.4.193 to 138.78.4.198138.78.4.1996
154138.78.4.200/29138.78.4.201 to 138.78.4.206138.78.4.2076
155138.78.4.208/29138.78.4.209 to 138.78.4.214138.78.4.2156
156138.78.4.216/29138.78.4.217 to 138.78.4.222138.78.4.2236
157138.78.4.224/29138.78.4.225 to 138.78.4.230138.78.4.2316
158138.78.4.232/29138.78.4.233 to 138.78.4.238138.78.4.2396
159138.78.4.240/29138.78.4.241 to 138.78.4.246138.78.4.2476
160138.78.4.248/29138.78.4.249 to 138.78.4.254138.78.4.2556
161138.78.5.0/29138.78.5.1 to 138.78.5.6138.78.5.76
162138.78.5.8/29138.78.5.9 to 138.78.5.14138.78.5.156
163138.78.5.16/29138.78.5.17 to 138.78.5.22138.78.5.236
164138.78.5.24/29138.78.5.25 to 138.78.5.30138.78.5.316
165138.78.5.32/29138.78.5.33 to 138.78.5.38138.78.5.396
166138.78.5.40/29138.78.5.41 to 138.78.5.46138.78.5.476
167138.78.5.48/29138.78.5.49 to 138.78.5.54138.78.5.556
168138.78.5.56/29138.78.5.57 to 138.78.5.62138.78.5.636
169138.78.5.64/29138.78.5.65 to 138.78.5.70138.78.5.716
170138.78.5.72/29138.78.5.73 to 138.78.5.78138.78.5.796
171138.78.5.80/29138.78.5.81 to 138.78.5.86138.78.5.876
172138.78.5.88/29138.78.5.89 to 138.78.5.94138.78.5.956
173138.78.5.96/29138.78.5.97 to 138.78.5.102138.78.5.1036
174138.78.5.104/29138.78.5.105 to 138.78.5.110138.78.5.1116
175138.78.5.112/29138.78.5.113 to 138.78.5.118138.78.5.1196
176138.78.5.120/29138.78.5.121 to 138.78.5.126138.78.5.1276
177138.78.5.128/29138.78.5.129 to 138.78.5.134138.78.5.1356
178138.78.5.136/29138.78.5.137 to 138.78.5.142138.78.5.1436
179138.78.5.144/29138.78.5.145 to 138.78.5.150138.78.5.1516
180138.78.5.152/29138.78.5.153 to 138.78.5.158138.78.5.1596
181138.78.5.160/29138.78.5.161 to 138.78.5.166138.78.5.1676
182138.78.5.168/29138.78.5.169 to 138.78.5.174138.78.5.1756
183138.78.5.176/29138.78.5.177 to 138.78.5.182138.78.5.1836
184138.78.5.184/29138.78.5.185 to 138.78.5.190138.78.5.1916
185138.78.5.192/29138.78.5.193 to 138.78.5.198138.78.5.1996
186138.78.5.200/29138.78.5.201 to 138.78.5.206138.78.5.2076
187138.78.5.208/29138.78.5.209 to 138.78.5.214138.78.5.2156
188138.78.5.216/29138.78.5.217 to 138.78.5.222138.78.5.2236
189138.78.5.224/29138.78.5.225 to 138.78.5.230138.78.5.2316
190138.78.5.232/29138.78.5.233 to 138.78.5.238138.78.5.2396
191138.78.5.240/29138.78.5.241 to 138.78.5.246138.78.5.2476
192138.78.5.248/29138.78.5.249 to 138.78.5.254138.78.5.2556
193138.78.6.0/29138.78.6.1 to 138.78.6.6138.78.6.76
194138.78.6.8/29138.78.6.9 to 138.78.6.14138.78.6.156
195138.78.6.16/29138.78.6.17 to 138.78.6.22138.78.6.236
196138.78.6.24/29138.78.6.25 to 138.78.6.30138.78.6.316
197138.78.6.32/29138.78.6.33 to 138.78.6.38138.78.6.396
198138.78.6.40/29138.78.6.41 to 138.78.6.46138.78.6.476
199138.78.6.48/29138.78.6.49 to 138.78.6.54138.78.6.556
200138.78.6.56/29138.78.6.57 to 138.78.6.62138.78.6.636
201138.78.6.64/29138.78.6.65 to 138.78.6.70138.78.6.716
202138.78.6.72/29138.78.6.73 to 138.78.6.78138.78.6.796
203138.78.6.80/29138.78.6.81 to 138.78.6.86138.78.6.876
204138.78.6.88/29138.78.6.89 to 138.78.6.94138.78.6.956
205138.78.6.96/29138.78.6.97 to 138.78.6.102138.78.6.1036
206138.78.6.104/29138.78.6.105 to 138.78.6.110138.78.6.1116
207138.78.6.112/29138.78.6.113 to 138.78.6.118138.78.6.1196
208138.78.6.120/29138.78.6.121 to 138.78.6.126138.78.6.1276
209138.78.6.128/29138.78.6.129 to 138.78.6.134138.78.6.1356
210138.78.6.136/29138.78.6.137 to 138.78.6.142138.78.6.1436
211138.78.6.144/29138.78.6.145 to 138.78.6.150138.78.6.1516
212138.78.6.152/29138.78.6.153 to 138.78.6.158138.78.6.1596
213138.78.6.160/29138.78.6.161 to 138.78.6.166138.78.6.1676
214138.78.6.168/29138.78.6.169 to 138.78.6.174138.78.6.1756
215138.78.6.176/29138.78.6.177 to 138.78.6.182138.78.6.1836
216138.78.6.184/29138.78.6.185 to 138.78.6.190138.78.6.1916
217138.78.6.192/29138.78.6.193 to 138.78.6.198138.78.6.1996
218138.78.6.200/29138.78.6.201 to 138.78.6.206138.78.6.2076
219138.78.6.208/29138.78.6.209 to 138.78.6.214138.78.6.2156
220138.78.6.216/29138.78.6.217 to 138.78.6.222138.78.6.2236
221138.78.6.224/29138.78.6.225 to 138.78.6.230138.78.6.2316
222138.78.6.232/29138.78.6.233 to 138.78.6.238138.78.6.2396
223138.78.6.240/29138.78.6.241 to 138.78.6.246138.78.6.2476
224138.78.6.248/29138.78.6.249 to 138.78.6.254138.78.6.2556
225138.78.7.0/29138.78.7.1 to 138.78.7.6138.78.7.76
226138.78.7.8/29138.78.7.9 to 138.78.7.14138.78.7.156
227138.78.7.16/29138.78.7.17 to 138.78.7.22138.78.7.236
228138.78.7.24/29138.78.7.25 to 138.78.7.30138.78.7.316
229138.78.7.32/29138.78.7.33 to 138.78.7.38138.78.7.396
230138.78.7.40/29138.78.7.41 to 138.78.7.46138.78.7.476
231138.78.7.48/29138.78.7.49 to 138.78.7.54138.78.7.556
232138.78.7.56/29138.78.7.57 to 138.78.7.62138.78.7.636
233138.78.7.64/29138.78.7.65 to 138.78.7.70138.78.7.716
234138.78.7.72/29138.78.7.73 to 138.78.7.78138.78.7.796
235138.78.7.80/29138.78.7.81 to 138.78.7.86138.78.7.876
236138.78.7.88/29138.78.7.89 to 138.78.7.94138.78.7.956
237138.78.7.96/29138.78.7.97 to 138.78.7.102138.78.7.1036
238138.78.7.104/29138.78.7.105 to 138.78.7.110138.78.7.1116
239138.78.7.112/29138.78.7.113 to 138.78.7.118138.78.7.1196
240138.78.7.120/29138.78.7.121 to 138.78.7.126138.78.7.1276
241138.78.7.128/29138.78.7.129 to 138.78.7.134138.78.7.1356
242138.78.7.136/29138.78.7.137 to 138.78.7.142138.78.7.1436
243138.78.7.144/29138.78.7.145 to 138.78.7.150138.78.7.1516
244138.78.7.152/29138.78.7.153 to 138.78.7.158138.78.7.1596
245138.78.7.160/29138.78.7.161 to 138.78.7.166138.78.7.1676
246138.78.7.168/29138.78.7.169 to 138.78.7.174138.78.7.1756
247138.78.7.176/29138.78.7.177 to 138.78.7.182138.78.7.1836
248138.78.7.184/29138.78.7.185 to 138.78.7.190138.78.7.1916
249138.78.7.192/29138.78.7.193 to 138.78.7.198138.78.7.1996
250138.78.7.200/29138.78.7.201 to 138.78.7.206138.78.7.2076
251138.78.7.208/29138.78.7.209 to 138.78.7.214138.78.7.2156
252138.78.7.216/29138.78.7.217 to 138.78.7.222138.78.7.2236
253138.78.7.224/29138.78.7.225 to 138.78.7.230138.78.7.2316
254138.78.7.232/29138.78.7.233 to 138.78.7.238138.78.7.2396
255138.78.7.240/29138.78.7.241 to 138.78.7.246138.78.7.2476
256138.78.7.248/29138.78.7.249 to 138.78.7.254138.78.7.2556

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.