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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.

Network201.78.0.0/17
Usable hosts32,766
Subnet mask255.255.128.0
Addresses32,768
Network address
201.78.0.0
Broadcast address
201.78.127.255
First usable
201.78.0.1
Last usable
201.78.127.254
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
C (default /24)
As numbers
Hex C94E0000 · Integer 3377332224 to 3377364991
Reverse DNS zones
0.78.201.in-addr.arpa
1.78.201.in-addr.arpa
2.78.201.in-addr.arpa
3.78.201.in-addr.arpa
4.78.201.in-addr.arpa
5.78.201.in-addr.arpa
6.78.201.in-addr.arpa
7.78.201.in-addr.arpa
8.78.201.in-addr.arpa
9.78.201.in-addr.arpa
10.78.201.in-addr.arpa
11.78.201.in-addr.arpa
12.78.201.in-addr.arpa
13.78.201.in-addr.arpa
14.78.201.in-addr.arpa
15.78.201.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
Address11001001.01001110.00000000.00000000201.78.0.0
Subnet mask11111111.11111111.10000000.00000000255.255.128.0
Network11001001.01001110.00000000.00000000201.78.0.0
Broadcast11001001.01001110.01111111.11111111201.78.127.255
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)

201.78.0.0/17 makes 2,048 subnets of /28; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1201.78.0.0/28201.78.0.1 to 201.78.0.14201.78.0.1514
2201.78.0.16/28201.78.0.17 to 201.78.0.30201.78.0.3114
3201.78.0.32/28201.78.0.33 to 201.78.0.46201.78.0.4714
4201.78.0.48/28201.78.0.49 to 201.78.0.62201.78.0.6314
5201.78.0.64/28201.78.0.65 to 201.78.0.78201.78.0.7914
6201.78.0.80/28201.78.0.81 to 201.78.0.94201.78.0.9514
7201.78.0.96/28201.78.0.97 to 201.78.0.110201.78.0.11114
8201.78.0.112/28201.78.0.113 to 201.78.0.126201.78.0.12714
9201.78.0.128/28201.78.0.129 to 201.78.0.142201.78.0.14314
10201.78.0.144/28201.78.0.145 to 201.78.0.158201.78.0.15914
11201.78.0.160/28201.78.0.161 to 201.78.0.174201.78.0.17514
12201.78.0.176/28201.78.0.177 to 201.78.0.190201.78.0.19114
13201.78.0.192/28201.78.0.193 to 201.78.0.206201.78.0.20714
14201.78.0.208/28201.78.0.209 to 201.78.0.222201.78.0.22314
15201.78.0.224/28201.78.0.225 to 201.78.0.238201.78.0.23914
16201.78.0.240/28201.78.0.241 to 201.78.0.254201.78.0.25514
17201.78.1.0/28201.78.1.1 to 201.78.1.14201.78.1.1514
18201.78.1.16/28201.78.1.17 to 201.78.1.30201.78.1.3114
19201.78.1.32/28201.78.1.33 to 201.78.1.46201.78.1.4714
20201.78.1.48/28201.78.1.49 to 201.78.1.62201.78.1.6314
21201.78.1.64/28201.78.1.65 to 201.78.1.78201.78.1.7914
22201.78.1.80/28201.78.1.81 to 201.78.1.94201.78.1.9514
23201.78.1.96/28201.78.1.97 to 201.78.1.110201.78.1.11114
24201.78.1.112/28201.78.1.113 to 201.78.1.126201.78.1.12714
25201.78.1.128/28201.78.1.129 to 201.78.1.142201.78.1.14314
26201.78.1.144/28201.78.1.145 to 201.78.1.158201.78.1.15914
27201.78.1.160/28201.78.1.161 to 201.78.1.174201.78.1.17514
28201.78.1.176/28201.78.1.177 to 201.78.1.190201.78.1.19114
29201.78.1.192/28201.78.1.193 to 201.78.1.206201.78.1.20714
30201.78.1.208/28201.78.1.209 to 201.78.1.222201.78.1.22314
31201.78.1.224/28201.78.1.225 to 201.78.1.238201.78.1.23914
32201.78.1.240/28201.78.1.241 to 201.78.1.254201.78.1.25514
33201.78.2.0/28201.78.2.1 to 201.78.2.14201.78.2.1514
34201.78.2.16/28201.78.2.17 to 201.78.2.30201.78.2.3114
35201.78.2.32/28201.78.2.33 to 201.78.2.46201.78.2.4714
36201.78.2.48/28201.78.2.49 to 201.78.2.62201.78.2.6314
37201.78.2.64/28201.78.2.65 to 201.78.2.78201.78.2.7914
38201.78.2.80/28201.78.2.81 to 201.78.2.94201.78.2.9514
39201.78.2.96/28201.78.2.97 to 201.78.2.110201.78.2.11114
40201.78.2.112/28201.78.2.113 to 201.78.2.126201.78.2.12714
41201.78.2.128/28201.78.2.129 to 201.78.2.142201.78.2.14314
42201.78.2.144/28201.78.2.145 to 201.78.2.158201.78.2.15914
43201.78.2.160/28201.78.2.161 to 201.78.2.174201.78.2.17514
44201.78.2.176/28201.78.2.177 to 201.78.2.190201.78.2.19114
45201.78.2.192/28201.78.2.193 to 201.78.2.206201.78.2.20714
46201.78.2.208/28201.78.2.209 to 201.78.2.222201.78.2.22314
47201.78.2.224/28201.78.2.225 to 201.78.2.238201.78.2.23914
48201.78.2.240/28201.78.2.241 to 201.78.2.254201.78.2.25514
49201.78.3.0/28201.78.3.1 to 201.78.3.14201.78.3.1514
50201.78.3.16/28201.78.3.17 to 201.78.3.30201.78.3.3114
51201.78.3.32/28201.78.3.33 to 201.78.3.46201.78.3.4714
52201.78.3.48/28201.78.3.49 to 201.78.3.62201.78.3.6314
53201.78.3.64/28201.78.3.65 to 201.78.3.78201.78.3.7914
54201.78.3.80/28201.78.3.81 to 201.78.3.94201.78.3.9514
55201.78.3.96/28201.78.3.97 to 201.78.3.110201.78.3.11114
56201.78.3.112/28201.78.3.113 to 201.78.3.126201.78.3.12714
57201.78.3.128/28201.78.3.129 to 201.78.3.142201.78.3.14314
58201.78.3.144/28201.78.3.145 to 201.78.3.158201.78.3.15914
59201.78.3.160/28201.78.3.161 to 201.78.3.174201.78.3.17514
60201.78.3.176/28201.78.3.177 to 201.78.3.190201.78.3.19114
61201.78.3.192/28201.78.3.193 to 201.78.3.206201.78.3.20714
62201.78.3.208/28201.78.3.209 to 201.78.3.222201.78.3.22314
63201.78.3.224/28201.78.3.225 to 201.78.3.238201.78.3.23914
64201.78.3.240/28201.78.3.241 to 201.78.3.254201.78.3.25514
65201.78.4.0/28201.78.4.1 to 201.78.4.14201.78.4.1514
66201.78.4.16/28201.78.4.17 to 201.78.4.30201.78.4.3114
67201.78.4.32/28201.78.4.33 to 201.78.4.46201.78.4.4714
68201.78.4.48/28201.78.4.49 to 201.78.4.62201.78.4.6314
69201.78.4.64/28201.78.4.65 to 201.78.4.78201.78.4.7914
70201.78.4.80/28201.78.4.81 to 201.78.4.94201.78.4.9514
71201.78.4.96/28201.78.4.97 to 201.78.4.110201.78.4.11114
72201.78.4.112/28201.78.4.113 to 201.78.4.126201.78.4.12714
73201.78.4.128/28201.78.4.129 to 201.78.4.142201.78.4.14314
74201.78.4.144/28201.78.4.145 to 201.78.4.158201.78.4.15914
75201.78.4.160/28201.78.4.161 to 201.78.4.174201.78.4.17514
76201.78.4.176/28201.78.4.177 to 201.78.4.190201.78.4.19114
77201.78.4.192/28201.78.4.193 to 201.78.4.206201.78.4.20714
78201.78.4.208/28201.78.4.209 to 201.78.4.222201.78.4.22314
79201.78.4.224/28201.78.4.225 to 201.78.4.238201.78.4.23914
80201.78.4.240/28201.78.4.241 to 201.78.4.254201.78.4.25514
81201.78.5.0/28201.78.5.1 to 201.78.5.14201.78.5.1514
82201.78.5.16/28201.78.5.17 to 201.78.5.30201.78.5.3114
83201.78.5.32/28201.78.5.33 to 201.78.5.46201.78.5.4714
84201.78.5.48/28201.78.5.49 to 201.78.5.62201.78.5.6314
85201.78.5.64/28201.78.5.65 to 201.78.5.78201.78.5.7914
86201.78.5.80/28201.78.5.81 to 201.78.5.94201.78.5.9514
87201.78.5.96/28201.78.5.97 to 201.78.5.110201.78.5.11114
88201.78.5.112/28201.78.5.113 to 201.78.5.126201.78.5.12714
89201.78.5.128/28201.78.5.129 to 201.78.5.142201.78.5.14314
90201.78.5.144/28201.78.5.145 to 201.78.5.158201.78.5.15914
91201.78.5.160/28201.78.5.161 to 201.78.5.174201.78.5.17514
92201.78.5.176/28201.78.5.177 to 201.78.5.190201.78.5.19114
93201.78.5.192/28201.78.5.193 to 201.78.5.206201.78.5.20714
94201.78.5.208/28201.78.5.209 to 201.78.5.222201.78.5.22314
95201.78.5.224/28201.78.5.225 to 201.78.5.238201.78.5.23914
96201.78.5.240/28201.78.5.241 to 201.78.5.254201.78.5.25514
97201.78.6.0/28201.78.6.1 to 201.78.6.14201.78.6.1514
98201.78.6.16/28201.78.6.17 to 201.78.6.30201.78.6.3114
99201.78.6.32/28201.78.6.33 to 201.78.6.46201.78.6.4714
100201.78.6.48/28201.78.6.49 to 201.78.6.62201.78.6.6314
101201.78.6.64/28201.78.6.65 to 201.78.6.78201.78.6.7914
102201.78.6.80/28201.78.6.81 to 201.78.6.94201.78.6.9514
103201.78.6.96/28201.78.6.97 to 201.78.6.110201.78.6.11114
104201.78.6.112/28201.78.6.113 to 201.78.6.126201.78.6.12714
105201.78.6.128/28201.78.6.129 to 201.78.6.142201.78.6.14314
106201.78.6.144/28201.78.6.145 to 201.78.6.158201.78.6.15914
107201.78.6.160/28201.78.6.161 to 201.78.6.174201.78.6.17514
108201.78.6.176/28201.78.6.177 to 201.78.6.190201.78.6.19114
109201.78.6.192/28201.78.6.193 to 201.78.6.206201.78.6.20714
110201.78.6.208/28201.78.6.209 to 201.78.6.222201.78.6.22314
111201.78.6.224/28201.78.6.225 to 201.78.6.238201.78.6.23914
112201.78.6.240/28201.78.6.241 to 201.78.6.254201.78.6.25514
113201.78.7.0/28201.78.7.1 to 201.78.7.14201.78.7.1514
114201.78.7.16/28201.78.7.17 to 201.78.7.30201.78.7.3114
115201.78.7.32/28201.78.7.33 to 201.78.7.46201.78.7.4714
116201.78.7.48/28201.78.7.49 to 201.78.7.62201.78.7.6314
117201.78.7.64/28201.78.7.65 to 201.78.7.78201.78.7.7914
118201.78.7.80/28201.78.7.81 to 201.78.7.94201.78.7.9514
119201.78.7.96/28201.78.7.97 to 201.78.7.110201.78.7.11114
120201.78.7.112/28201.78.7.113 to 201.78.7.126201.78.7.12714
121201.78.7.128/28201.78.7.129 to 201.78.7.142201.78.7.14314
122201.78.7.144/28201.78.7.145 to 201.78.7.158201.78.7.15914
123201.78.7.160/28201.78.7.161 to 201.78.7.174201.78.7.17514
124201.78.7.176/28201.78.7.177 to 201.78.7.190201.78.7.19114
125201.78.7.192/28201.78.7.193 to 201.78.7.206201.78.7.20714
126201.78.7.208/28201.78.7.209 to 201.78.7.222201.78.7.22314
127201.78.7.224/28201.78.7.225 to 201.78.7.238201.78.7.23914
128201.78.7.240/28201.78.7.241 to 201.78.7.254201.78.7.25514
129201.78.8.0/28201.78.8.1 to 201.78.8.14201.78.8.1514
130201.78.8.16/28201.78.8.17 to 201.78.8.30201.78.8.3114
131201.78.8.32/28201.78.8.33 to 201.78.8.46201.78.8.4714
132201.78.8.48/28201.78.8.49 to 201.78.8.62201.78.8.6314
133201.78.8.64/28201.78.8.65 to 201.78.8.78201.78.8.7914
134201.78.8.80/28201.78.8.81 to 201.78.8.94201.78.8.9514
135201.78.8.96/28201.78.8.97 to 201.78.8.110201.78.8.11114
136201.78.8.112/28201.78.8.113 to 201.78.8.126201.78.8.12714
137201.78.8.128/28201.78.8.129 to 201.78.8.142201.78.8.14314
138201.78.8.144/28201.78.8.145 to 201.78.8.158201.78.8.15914
139201.78.8.160/28201.78.8.161 to 201.78.8.174201.78.8.17514
140201.78.8.176/28201.78.8.177 to 201.78.8.190201.78.8.19114
141201.78.8.192/28201.78.8.193 to 201.78.8.206201.78.8.20714
142201.78.8.208/28201.78.8.209 to 201.78.8.222201.78.8.22314
143201.78.8.224/28201.78.8.225 to 201.78.8.238201.78.8.23914
144201.78.8.240/28201.78.8.241 to 201.78.8.254201.78.8.25514
145201.78.9.0/28201.78.9.1 to 201.78.9.14201.78.9.1514
146201.78.9.16/28201.78.9.17 to 201.78.9.30201.78.9.3114
147201.78.9.32/28201.78.9.33 to 201.78.9.46201.78.9.4714
148201.78.9.48/28201.78.9.49 to 201.78.9.62201.78.9.6314
149201.78.9.64/28201.78.9.65 to 201.78.9.78201.78.9.7914
150201.78.9.80/28201.78.9.81 to 201.78.9.94201.78.9.9514
151201.78.9.96/28201.78.9.97 to 201.78.9.110201.78.9.11114
152201.78.9.112/28201.78.9.113 to 201.78.9.126201.78.9.12714
153201.78.9.128/28201.78.9.129 to 201.78.9.142201.78.9.14314
154201.78.9.144/28201.78.9.145 to 201.78.9.158201.78.9.15914
155201.78.9.160/28201.78.9.161 to 201.78.9.174201.78.9.17514
156201.78.9.176/28201.78.9.177 to 201.78.9.190201.78.9.19114
157201.78.9.192/28201.78.9.193 to 201.78.9.206201.78.9.20714
158201.78.9.208/28201.78.9.209 to 201.78.9.222201.78.9.22314
159201.78.9.224/28201.78.9.225 to 201.78.9.238201.78.9.23914
160201.78.9.240/28201.78.9.241 to 201.78.9.254201.78.9.25514
161201.78.10.0/28201.78.10.1 to 201.78.10.14201.78.10.1514
162201.78.10.16/28201.78.10.17 to 201.78.10.30201.78.10.3114
163201.78.10.32/28201.78.10.33 to 201.78.10.46201.78.10.4714
164201.78.10.48/28201.78.10.49 to 201.78.10.62201.78.10.6314
165201.78.10.64/28201.78.10.65 to 201.78.10.78201.78.10.7914
166201.78.10.80/28201.78.10.81 to 201.78.10.94201.78.10.9514
167201.78.10.96/28201.78.10.97 to 201.78.10.110201.78.10.11114
168201.78.10.112/28201.78.10.113 to 201.78.10.126201.78.10.12714
169201.78.10.128/28201.78.10.129 to 201.78.10.142201.78.10.14314
170201.78.10.144/28201.78.10.145 to 201.78.10.158201.78.10.15914
171201.78.10.160/28201.78.10.161 to 201.78.10.174201.78.10.17514
172201.78.10.176/28201.78.10.177 to 201.78.10.190201.78.10.19114
173201.78.10.192/28201.78.10.193 to 201.78.10.206201.78.10.20714
174201.78.10.208/28201.78.10.209 to 201.78.10.222201.78.10.22314
175201.78.10.224/28201.78.10.225 to 201.78.10.238201.78.10.23914
176201.78.10.240/28201.78.10.241 to 201.78.10.254201.78.10.25514
177201.78.11.0/28201.78.11.1 to 201.78.11.14201.78.11.1514
178201.78.11.16/28201.78.11.17 to 201.78.11.30201.78.11.3114
179201.78.11.32/28201.78.11.33 to 201.78.11.46201.78.11.4714
180201.78.11.48/28201.78.11.49 to 201.78.11.62201.78.11.6314
181201.78.11.64/28201.78.11.65 to 201.78.11.78201.78.11.7914
182201.78.11.80/28201.78.11.81 to 201.78.11.94201.78.11.9514
183201.78.11.96/28201.78.11.97 to 201.78.11.110201.78.11.11114
184201.78.11.112/28201.78.11.113 to 201.78.11.126201.78.11.12714
185201.78.11.128/28201.78.11.129 to 201.78.11.142201.78.11.14314
186201.78.11.144/28201.78.11.145 to 201.78.11.158201.78.11.15914
187201.78.11.160/28201.78.11.161 to 201.78.11.174201.78.11.17514
188201.78.11.176/28201.78.11.177 to 201.78.11.190201.78.11.19114
189201.78.11.192/28201.78.11.193 to 201.78.11.206201.78.11.20714
190201.78.11.208/28201.78.11.209 to 201.78.11.222201.78.11.22314
191201.78.11.224/28201.78.11.225 to 201.78.11.238201.78.11.23914
192201.78.11.240/28201.78.11.241 to 201.78.11.254201.78.11.25514
193201.78.12.0/28201.78.12.1 to 201.78.12.14201.78.12.1514
194201.78.12.16/28201.78.12.17 to 201.78.12.30201.78.12.3114
195201.78.12.32/28201.78.12.33 to 201.78.12.46201.78.12.4714
196201.78.12.48/28201.78.12.49 to 201.78.12.62201.78.12.6314
197201.78.12.64/28201.78.12.65 to 201.78.12.78201.78.12.7914
198201.78.12.80/28201.78.12.81 to 201.78.12.94201.78.12.9514
199201.78.12.96/28201.78.12.97 to 201.78.12.110201.78.12.11114
200201.78.12.112/28201.78.12.113 to 201.78.12.126201.78.12.12714
201201.78.12.128/28201.78.12.129 to 201.78.12.142201.78.12.14314
202201.78.12.144/28201.78.12.145 to 201.78.12.158201.78.12.15914
203201.78.12.160/28201.78.12.161 to 201.78.12.174201.78.12.17514
204201.78.12.176/28201.78.12.177 to 201.78.12.190201.78.12.19114
205201.78.12.192/28201.78.12.193 to 201.78.12.206201.78.12.20714
206201.78.12.208/28201.78.12.209 to 201.78.12.222201.78.12.22314
207201.78.12.224/28201.78.12.225 to 201.78.12.238201.78.12.23914
208201.78.12.240/28201.78.12.241 to 201.78.12.254201.78.12.25514
209201.78.13.0/28201.78.13.1 to 201.78.13.14201.78.13.1514
210201.78.13.16/28201.78.13.17 to 201.78.13.30201.78.13.3114
211201.78.13.32/28201.78.13.33 to 201.78.13.46201.78.13.4714
212201.78.13.48/28201.78.13.49 to 201.78.13.62201.78.13.6314
213201.78.13.64/28201.78.13.65 to 201.78.13.78201.78.13.7914
214201.78.13.80/28201.78.13.81 to 201.78.13.94201.78.13.9514
215201.78.13.96/28201.78.13.97 to 201.78.13.110201.78.13.11114
216201.78.13.112/28201.78.13.113 to 201.78.13.126201.78.13.12714
217201.78.13.128/28201.78.13.129 to 201.78.13.142201.78.13.14314
218201.78.13.144/28201.78.13.145 to 201.78.13.158201.78.13.15914
219201.78.13.160/28201.78.13.161 to 201.78.13.174201.78.13.17514
220201.78.13.176/28201.78.13.177 to 201.78.13.190201.78.13.19114
221201.78.13.192/28201.78.13.193 to 201.78.13.206201.78.13.20714
222201.78.13.208/28201.78.13.209 to 201.78.13.222201.78.13.22314
223201.78.13.224/28201.78.13.225 to 201.78.13.238201.78.13.23914
224201.78.13.240/28201.78.13.241 to 201.78.13.254201.78.13.25514
225201.78.14.0/28201.78.14.1 to 201.78.14.14201.78.14.1514
226201.78.14.16/28201.78.14.17 to 201.78.14.30201.78.14.3114
227201.78.14.32/28201.78.14.33 to 201.78.14.46201.78.14.4714
228201.78.14.48/28201.78.14.49 to 201.78.14.62201.78.14.6314
229201.78.14.64/28201.78.14.65 to 201.78.14.78201.78.14.7914
230201.78.14.80/28201.78.14.81 to 201.78.14.94201.78.14.9514
231201.78.14.96/28201.78.14.97 to 201.78.14.110201.78.14.11114
232201.78.14.112/28201.78.14.113 to 201.78.14.126201.78.14.12714
233201.78.14.128/28201.78.14.129 to 201.78.14.142201.78.14.14314
234201.78.14.144/28201.78.14.145 to 201.78.14.158201.78.14.15914
235201.78.14.160/28201.78.14.161 to 201.78.14.174201.78.14.17514
236201.78.14.176/28201.78.14.177 to 201.78.14.190201.78.14.19114
237201.78.14.192/28201.78.14.193 to 201.78.14.206201.78.14.20714
238201.78.14.208/28201.78.14.209 to 201.78.14.222201.78.14.22314
239201.78.14.224/28201.78.14.225 to 201.78.14.238201.78.14.23914
240201.78.14.240/28201.78.14.241 to 201.78.14.254201.78.14.25514
241201.78.15.0/28201.78.15.1 to 201.78.15.14201.78.15.1514
242201.78.15.16/28201.78.15.17 to 201.78.15.30201.78.15.3114
243201.78.15.32/28201.78.15.33 to 201.78.15.46201.78.15.4714
244201.78.15.48/28201.78.15.49 to 201.78.15.62201.78.15.6314
245201.78.15.64/28201.78.15.65 to 201.78.15.78201.78.15.7914
246201.78.15.80/28201.78.15.81 to 201.78.15.94201.78.15.9514
247201.78.15.96/28201.78.15.97 to 201.78.15.110201.78.15.11114
248201.78.15.112/28201.78.15.113 to 201.78.15.126201.78.15.12714
249201.78.15.128/28201.78.15.129 to 201.78.15.142201.78.15.14314
250201.78.15.144/28201.78.15.145 to 201.78.15.158201.78.15.15914
251201.78.15.160/28201.78.15.161 to 201.78.15.174201.78.15.17514
252201.78.15.176/28201.78.15.177 to 201.78.15.190201.78.15.19114
253201.78.15.192/28201.78.15.193 to 201.78.15.206201.78.15.20714
254201.78.15.208/28201.78.15.209 to 201.78.15.222201.78.15.22314
255201.78.15.224/28201.78.15.225 to 201.78.15.238201.78.15.23914
256201.78.15.240/28201.78.15.241 to 201.78.15.254201.78.15.25514

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.