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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.

Network201.192.0.0/10
Usable hosts4,194,302
Subnet mask255.192.0.0
Addresses4,194,304
Network address
201.192.0.0
Broadcast address
201.255.255.255
First usable
201.192.0.1
Last usable
201.255.255.254
Usable hosts
4,194,302 (4,194,304 less the network and broadcast addresses)
Subnet mask
255.192.0.0
Wildcard mask
0.63.255.255 (Cisco ACLs, OSPF)
Prefix length
/10
Type
Public public
Old class
C (default /24)
As numbers
Hex C9C00000 · Integer 3384803328 to 3388997631
Reverse DNS zones
192.201.in-addr.arpa
193.201.in-addr.arpa
194.201.in-addr.arpa
195.201.in-addr.arpa
196.201.in-addr.arpa
197.201.in-addr.arpa
198.201.in-addr.arpa
199.201.in-addr.arpa
200.201.in-addr.arpa
201.201.in-addr.arpa
202.201.in-addr.arpa
203.201.in-addr.arpa
204.201.in-addr.arpa
205.201.in-addr.arpa
206.201.in-addr.arpa
207.201.in-addr.arpa
and 48 more
/10 is not on a 8-bit boundary, so it takes 64 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11001001.11000000.00000000.00000000201.192.0.0
Subnet mask11111111.11000000.00000000.00000000255.192.0.0
Network11001001.11000000.00000000.00000000201.192.0.0
Broadcast11001001.11111111.11111111.11111111201.255.255.255
Split into smaller subnets/18
/11 (2)/12 (4)/13 (8)/14 (16)/15 (32)/16 (64)/17 (128)/18 (256)/19 (512)/20 (1,024)/21 (2,048)/22 (4,096)

201.192.0.0/10 makes 256 subnets of /18.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1201.192.0.0/18201.192.0.1 to 201.192.63.254201.192.63.25516,382
2201.192.64.0/18201.192.64.1 to 201.192.127.254201.192.127.25516,382
3201.192.128.0/18201.192.128.1 to 201.192.191.254201.192.191.25516,382
4201.192.192.0/18201.192.192.1 to 201.192.255.254201.192.255.25516,382
5201.193.0.0/18201.193.0.1 to 201.193.63.254201.193.63.25516,382
6201.193.64.0/18201.193.64.1 to 201.193.127.254201.193.127.25516,382
7201.193.128.0/18201.193.128.1 to 201.193.191.254201.193.191.25516,382
8201.193.192.0/18201.193.192.1 to 201.193.255.254201.193.255.25516,382
9201.194.0.0/18201.194.0.1 to 201.194.63.254201.194.63.25516,382
10201.194.64.0/18201.194.64.1 to 201.194.127.254201.194.127.25516,382
11201.194.128.0/18201.194.128.1 to 201.194.191.254201.194.191.25516,382
12201.194.192.0/18201.194.192.1 to 201.194.255.254201.194.255.25516,382
13201.195.0.0/18201.195.0.1 to 201.195.63.254201.195.63.25516,382
14201.195.64.0/18201.195.64.1 to 201.195.127.254201.195.127.25516,382
15201.195.128.0/18201.195.128.1 to 201.195.191.254201.195.191.25516,382
16201.195.192.0/18201.195.192.1 to 201.195.255.254201.195.255.25516,382
17201.196.0.0/18201.196.0.1 to 201.196.63.254201.196.63.25516,382
18201.196.64.0/18201.196.64.1 to 201.196.127.254201.196.127.25516,382
19201.196.128.0/18201.196.128.1 to 201.196.191.254201.196.191.25516,382
20201.196.192.0/18201.196.192.1 to 201.196.255.254201.196.255.25516,382
21201.197.0.0/18201.197.0.1 to 201.197.63.254201.197.63.25516,382
22201.197.64.0/18201.197.64.1 to 201.197.127.254201.197.127.25516,382
23201.197.128.0/18201.197.128.1 to 201.197.191.254201.197.191.25516,382
24201.197.192.0/18201.197.192.1 to 201.197.255.254201.197.255.25516,382
25201.198.0.0/18201.198.0.1 to 201.198.63.254201.198.63.25516,382
26201.198.64.0/18201.198.64.1 to 201.198.127.254201.198.127.25516,382
27201.198.128.0/18201.198.128.1 to 201.198.191.254201.198.191.25516,382
28201.198.192.0/18201.198.192.1 to 201.198.255.254201.198.255.25516,382
29201.199.0.0/18201.199.0.1 to 201.199.63.254201.199.63.25516,382
30201.199.64.0/18201.199.64.1 to 201.199.127.254201.199.127.25516,382
31201.199.128.0/18201.199.128.1 to 201.199.191.254201.199.191.25516,382
32201.199.192.0/18201.199.192.1 to 201.199.255.254201.199.255.25516,382
33201.200.0.0/18201.200.0.1 to 201.200.63.254201.200.63.25516,382
34201.200.64.0/18201.200.64.1 to 201.200.127.254201.200.127.25516,382
35201.200.128.0/18201.200.128.1 to 201.200.191.254201.200.191.25516,382
36201.200.192.0/18201.200.192.1 to 201.200.255.254201.200.255.25516,382
37201.201.0.0/18201.201.0.1 to 201.201.63.254201.201.63.25516,382
38201.201.64.0/18201.201.64.1 to 201.201.127.254201.201.127.25516,382
39201.201.128.0/18201.201.128.1 to 201.201.191.254201.201.191.25516,382
40201.201.192.0/18201.201.192.1 to 201.201.255.254201.201.255.25516,382
41201.202.0.0/18201.202.0.1 to 201.202.63.254201.202.63.25516,382
42201.202.64.0/18201.202.64.1 to 201.202.127.254201.202.127.25516,382
43201.202.128.0/18201.202.128.1 to 201.202.191.254201.202.191.25516,382
44201.202.192.0/18201.202.192.1 to 201.202.255.254201.202.255.25516,382
45201.203.0.0/18201.203.0.1 to 201.203.63.254201.203.63.25516,382
46201.203.64.0/18201.203.64.1 to 201.203.127.254201.203.127.25516,382
47201.203.128.0/18201.203.128.1 to 201.203.191.254201.203.191.25516,382
48201.203.192.0/18201.203.192.1 to 201.203.255.254201.203.255.25516,382
49201.204.0.0/18201.204.0.1 to 201.204.63.254201.204.63.25516,382
50201.204.64.0/18201.204.64.1 to 201.204.127.254201.204.127.25516,382
51201.204.128.0/18201.204.128.1 to 201.204.191.254201.204.191.25516,382
52201.204.192.0/18201.204.192.1 to 201.204.255.254201.204.255.25516,382
53201.205.0.0/18201.205.0.1 to 201.205.63.254201.205.63.25516,382
54201.205.64.0/18201.205.64.1 to 201.205.127.254201.205.127.25516,382
55201.205.128.0/18201.205.128.1 to 201.205.191.254201.205.191.25516,382
56201.205.192.0/18201.205.192.1 to 201.205.255.254201.205.255.25516,382
57201.206.0.0/18201.206.0.1 to 201.206.63.254201.206.63.25516,382
58201.206.64.0/18201.206.64.1 to 201.206.127.254201.206.127.25516,382
59201.206.128.0/18201.206.128.1 to 201.206.191.254201.206.191.25516,382
60201.206.192.0/18201.206.192.1 to 201.206.255.254201.206.255.25516,382
61201.207.0.0/18201.207.0.1 to 201.207.63.254201.207.63.25516,382
62201.207.64.0/18201.207.64.1 to 201.207.127.254201.207.127.25516,382
63201.207.128.0/18201.207.128.1 to 201.207.191.254201.207.191.25516,382
64201.207.192.0/18201.207.192.1 to 201.207.255.254201.207.255.25516,382
65201.208.0.0/18201.208.0.1 to 201.208.63.254201.208.63.25516,382
66201.208.64.0/18201.208.64.1 to 201.208.127.254201.208.127.25516,382
67201.208.128.0/18201.208.128.1 to 201.208.191.254201.208.191.25516,382
68201.208.192.0/18201.208.192.1 to 201.208.255.254201.208.255.25516,382
69201.209.0.0/18201.209.0.1 to 201.209.63.254201.209.63.25516,382
70201.209.64.0/18201.209.64.1 to 201.209.127.254201.209.127.25516,382
71201.209.128.0/18201.209.128.1 to 201.209.191.254201.209.191.25516,382
72201.209.192.0/18201.209.192.1 to 201.209.255.254201.209.255.25516,382
73201.210.0.0/18201.210.0.1 to 201.210.63.254201.210.63.25516,382
74201.210.64.0/18201.210.64.1 to 201.210.127.254201.210.127.25516,382
75201.210.128.0/18201.210.128.1 to 201.210.191.254201.210.191.25516,382
76201.210.192.0/18201.210.192.1 to 201.210.255.254201.210.255.25516,382
77201.211.0.0/18201.211.0.1 to 201.211.63.254201.211.63.25516,382
78201.211.64.0/18201.211.64.1 to 201.211.127.254201.211.127.25516,382
79201.211.128.0/18201.211.128.1 to 201.211.191.254201.211.191.25516,382
80201.211.192.0/18201.211.192.1 to 201.211.255.254201.211.255.25516,382
81201.212.0.0/18201.212.0.1 to 201.212.63.254201.212.63.25516,382
82201.212.64.0/18201.212.64.1 to 201.212.127.254201.212.127.25516,382
83201.212.128.0/18201.212.128.1 to 201.212.191.254201.212.191.25516,382
84201.212.192.0/18201.212.192.1 to 201.212.255.254201.212.255.25516,382
85201.213.0.0/18201.213.0.1 to 201.213.63.254201.213.63.25516,382
86201.213.64.0/18201.213.64.1 to 201.213.127.254201.213.127.25516,382
87201.213.128.0/18201.213.128.1 to 201.213.191.254201.213.191.25516,382
88201.213.192.0/18201.213.192.1 to 201.213.255.254201.213.255.25516,382
89201.214.0.0/18201.214.0.1 to 201.214.63.254201.214.63.25516,382
90201.214.64.0/18201.214.64.1 to 201.214.127.254201.214.127.25516,382
91201.214.128.0/18201.214.128.1 to 201.214.191.254201.214.191.25516,382
92201.214.192.0/18201.214.192.1 to 201.214.255.254201.214.255.25516,382
93201.215.0.0/18201.215.0.1 to 201.215.63.254201.215.63.25516,382
94201.215.64.0/18201.215.64.1 to 201.215.127.254201.215.127.25516,382
95201.215.128.0/18201.215.128.1 to 201.215.191.254201.215.191.25516,382
96201.215.192.0/18201.215.192.1 to 201.215.255.254201.215.255.25516,382
97201.216.0.0/18201.216.0.1 to 201.216.63.254201.216.63.25516,382
98201.216.64.0/18201.216.64.1 to 201.216.127.254201.216.127.25516,382
99201.216.128.0/18201.216.128.1 to 201.216.191.254201.216.191.25516,382
100201.216.192.0/18201.216.192.1 to 201.216.255.254201.216.255.25516,382
101201.217.0.0/18201.217.0.1 to 201.217.63.254201.217.63.25516,382
102201.217.64.0/18201.217.64.1 to 201.217.127.254201.217.127.25516,382
103201.217.128.0/18201.217.128.1 to 201.217.191.254201.217.191.25516,382
104201.217.192.0/18201.217.192.1 to 201.217.255.254201.217.255.25516,382
105201.218.0.0/18201.218.0.1 to 201.218.63.254201.218.63.25516,382
106201.218.64.0/18201.218.64.1 to 201.218.127.254201.218.127.25516,382
107201.218.128.0/18201.218.128.1 to 201.218.191.254201.218.191.25516,382
108201.218.192.0/18201.218.192.1 to 201.218.255.254201.218.255.25516,382
109201.219.0.0/18201.219.0.1 to 201.219.63.254201.219.63.25516,382
110201.219.64.0/18201.219.64.1 to 201.219.127.254201.219.127.25516,382
111201.219.128.0/18201.219.128.1 to 201.219.191.254201.219.191.25516,382
112201.219.192.0/18201.219.192.1 to 201.219.255.254201.219.255.25516,382
113201.220.0.0/18201.220.0.1 to 201.220.63.254201.220.63.25516,382
114201.220.64.0/18201.220.64.1 to 201.220.127.254201.220.127.25516,382
115201.220.128.0/18201.220.128.1 to 201.220.191.254201.220.191.25516,382
116201.220.192.0/18201.220.192.1 to 201.220.255.254201.220.255.25516,382
117201.221.0.0/18201.221.0.1 to 201.221.63.254201.221.63.25516,382
118201.221.64.0/18201.221.64.1 to 201.221.127.254201.221.127.25516,382
119201.221.128.0/18201.221.128.1 to 201.221.191.254201.221.191.25516,382
120201.221.192.0/18201.221.192.1 to 201.221.255.254201.221.255.25516,382
121201.222.0.0/18201.222.0.1 to 201.222.63.254201.222.63.25516,382
122201.222.64.0/18201.222.64.1 to 201.222.127.254201.222.127.25516,382
123201.222.128.0/18201.222.128.1 to 201.222.191.254201.222.191.25516,382
124201.222.192.0/18201.222.192.1 to 201.222.255.254201.222.255.25516,382
125201.223.0.0/18201.223.0.1 to 201.223.63.254201.223.63.25516,382
126201.223.64.0/18201.223.64.1 to 201.223.127.254201.223.127.25516,382
127201.223.128.0/18201.223.128.1 to 201.223.191.254201.223.191.25516,382
128201.223.192.0/18201.223.192.1 to 201.223.255.254201.223.255.25516,382
129201.224.0.0/18201.224.0.1 to 201.224.63.254201.224.63.25516,382
130201.224.64.0/18201.224.64.1 to 201.224.127.254201.224.127.25516,382
131201.224.128.0/18201.224.128.1 to 201.224.191.254201.224.191.25516,382
132201.224.192.0/18201.224.192.1 to 201.224.255.254201.224.255.25516,382
133201.225.0.0/18201.225.0.1 to 201.225.63.254201.225.63.25516,382
134201.225.64.0/18201.225.64.1 to 201.225.127.254201.225.127.25516,382
135201.225.128.0/18201.225.128.1 to 201.225.191.254201.225.191.25516,382
136201.225.192.0/18201.225.192.1 to 201.225.255.254201.225.255.25516,382
137201.226.0.0/18201.226.0.1 to 201.226.63.254201.226.63.25516,382
138201.226.64.0/18201.226.64.1 to 201.226.127.254201.226.127.25516,382
139201.226.128.0/18201.226.128.1 to 201.226.191.254201.226.191.25516,382
140201.226.192.0/18201.226.192.1 to 201.226.255.254201.226.255.25516,382
141201.227.0.0/18201.227.0.1 to 201.227.63.254201.227.63.25516,382
142201.227.64.0/18201.227.64.1 to 201.227.127.254201.227.127.25516,382
143201.227.128.0/18201.227.128.1 to 201.227.191.254201.227.191.25516,382
144201.227.192.0/18201.227.192.1 to 201.227.255.254201.227.255.25516,382
145201.228.0.0/18201.228.0.1 to 201.228.63.254201.228.63.25516,382
146201.228.64.0/18201.228.64.1 to 201.228.127.254201.228.127.25516,382
147201.228.128.0/18201.228.128.1 to 201.228.191.254201.228.191.25516,382
148201.228.192.0/18201.228.192.1 to 201.228.255.254201.228.255.25516,382
149201.229.0.0/18201.229.0.1 to 201.229.63.254201.229.63.25516,382
150201.229.64.0/18201.229.64.1 to 201.229.127.254201.229.127.25516,382
151201.229.128.0/18201.229.128.1 to 201.229.191.254201.229.191.25516,382
152201.229.192.0/18201.229.192.1 to 201.229.255.254201.229.255.25516,382
153201.230.0.0/18201.230.0.1 to 201.230.63.254201.230.63.25516,382
154201.230.64.0/18201.230.64.1 to 201.230.127.254201.230.127.25516,382
155201.230.128.0/18201.230.128.1 to 201.230.191.254201.230.191.25516,382
156201.230.192.0/18201.230.192.1 to 201.230.255.254201.230.255.25516,382
157201.231.0.0/18201.231.0.1 to 201.231.63.254201.231.63.25516,382
158201.231.64.0/18201.231.64.1 to 201.231.127.254201.231.127.25516,382
159201.231.128.0/18201.231.128.1 to 201.231.191.254201.231.191.25516,382
160201.231.192.0/18201.231.192.1 to 201.231.255.254201.231.255.25516,382
161201.232.0.0/18201.232.0.1 to 201.232.63.254201.232.63.25516,382
162201.232.64.0/18201.232.64.1 to 201.232.127.254201.232.127.25516,382
163201.232.128.0/18201.232.128.1 to 201.232.191.254201.232.191.25516,382
164201.232.192.0/18201.232.192.1 to 201.232.255.254201.232.255.25516,382
165201.233.0.0/18201.233.0.1 to 201.233.63.254201.233.63.25516,382
166201.233.64.0/18201.233.64.1 to 201.233.127.254201.233.127.25516,382
167201.233.128.0/18201.233.128.1 to 201.233.191.254201.233.191.25516,382
168201.233.192.0/18201.233.192.1 to 201.233.255.254201.233.255.25516,382
169201.234.0.0/18201.234.0.1 to 201.234.63.254201.234.63.25516,382
170201.234.64.0/18201.234.64.1 to 201.234.127.254201.234.127.25516,382
171201.234.128.0/18201.234.128.1 to 201.234.191.254201.234.191.25516,382
172201.234.192.0/18201.234.192.1 to 201.234.255.254201.234.255.25516,382
173201.235.0.0/18201.235.0.1 to 201.235.63.254201.235.63.25516,382
174201.235.64.0/18201.235.64.1 to 201.235.127.254201.235.127.25516,382
175201.235.128.0/18201.235.128.1 to 201.235.191.254201.235.191.25516,382
176201.235.192.0/18201.235.192.1 to 201.235.255.254201.235.255.25516,382
177201.236.0.0/18201.236.0.1 to 201.236.63.254201.236.63.25516,382
178201.236.64.0/18201.236.64.1 to 201.236.127.254201.236.127.25516,382
179201.236.128.0/18201.236.128.1 to 201.236.191.254201.236.191.25516,382
180201.236.192.0/18201.236.192.1 to 201.236.255.254201.236.255.25516,382
181201.237.0.0/18201.237.0.1 to 201.237.63.254201.237.63.25516,382
182201.237.64.0/18201.237.64.1 to 201.237.127.254201.237.127.25516,382
183201.237.128.0/18201.237.128.1 to 201.237.191.254201.237.191.25516,382
184201.237.192.0/18201.237.192.1 to 201.237.255.254201.237.255.25516,382
185201.238.0.0/18201.238.0.1 to 201.238.63.254201.238.63.25516,382
186201.238.64.0/18201.238.64.1 to 201.238.127.254201.238.127.25516,382
187201.238.128.0/18201.238.128.1 to 201.238.191.254201.238.191.25516,382
188201.238.192.0/18201.238.192.1 to 201.238.255.254201.238.255.25516,382
189201.239.0.0/18201.239.0.1 to 201.239.63.254201.239.63.25516,382
190201.239.64.0/18201.239.64.1 to 201.239.127.254201.239.127.25516,382
191201.239.128.0/18201.239.128.1 to 201.239.191.254201.239.191.25516,382
192201.239.192.0/18201.239.192.1 to 201.239.255.254201.239.255.25516,382
193201.240.0.0/18201.240.0.1 to 201.240.63.254201.240.63.25516,382
194201.240.64.0/18201.240.64.1 to 201.240.127.254201.240.127.25516,382
195201.240.128.0/18201.240.128.1 to 201.240.191.254201.240.191.25516,382
196201.240.192.0/18201.240.192.1 to 201.240.255.254201.240.255.25516,382
197201.241.0.0/18201.241.0.1 to 201.241.63.254201.241.63.25516,382
198201.241.64.0/18201.241.64.1 to 201.241.127.254201.241.127.25516,382
199201.241.128.0/18201.241.128.1 to 201.241.191.254201.241.191.25516,382
200201.241.192.0/18201.241.192.1 to 201.241.255.254201.241.255.25516,382
201201.242.0.0/18201.242.0.1 to 201.242.63.254201.242.63.25516,382
202201.242.64.0/18201.242.64.1 to 201.242.127.254201.242.127.25516,382
203201.242.128.0/18201.242.128.1 to 201.242.191.254201.242.191.25516,382
204201.242.192.0/18201.242.192.1 to 201.242.255.254201.242.255.25516,382
205201.243.0.0/18201.243.0.1 to 201.243.63.254201.243.63.25516,382
206201.243.64.0/18201.243.64.1 to 201.243.127.254201.243.127.25516,382
207201.243.128.0/18201.243.128.1 to 201.243.191.254201.243.191.25516,382
208201.243.192.0/18201.243.192.1 to 201.243.255.254201.243.255.25516,382
209201.244.0.0/18201.244.0.1 to 201.244.63.254201.244.63.25516,382
210201.244.64.0/18201.244.64.1 to 201.244.127.254201.244.127.25516,382
211201.244.128.0/18201.244.128.1 to 201.244.191.254201.244.191.25516,382
212201.244.192.0/18201.244.192.1 to 201.244.255.254201.244.255.25516,382
213201.245.0.0/18201.245.0.1 to 201.245.63.254201.245.63.25516,382
214201.245.64.0/18201.245.64.1 to 201.245.127.254201.245.127.25516,382
215201.245.128.0/18201.245.128.1 to 201.245.191.254201.245.191.25516,382
216201.245.192.0/18201.245.192.1 to 201.245.255.254201.245.255.25516,382
217201.246.0.0/18201.246.0.1 to 201.246.63.254201.246.63.25516,382
218201.246.64.0/18201.246.64.1 to 201.246.127.254201.246.127.25516,382
219201.246.128.0/18201.246.128.1 to 201.246.191.254201.246.191.25516,382
220201.246.192.0/18201.246.192.1 to 201.246.255.254201.246.255.25516,382
221201.247.0.0/18201.247.0.1 to 201.247.63.254201.247.63.25516,382
222201.247.64.0/18201.247.64.1 to 201.247.127.254201.247.127.25516,382
223201.247.128.0/18201.247.128.1 to 201.247.191.254201.247.191.25516,382
224201.247.192.0/18201.247.192.1 to 201.247.255.254201.247.255.25516,382
225201.248.0.0/18201.248.0.1 to 201.248.63.254201.248.63.25516,382
226201.248.64.0/18201.248.64.1 to 201.248.127.254201.248.127.25516,382
227201.248.128.0/18201.248.128.1 to 201.248.191.254201.248.191.25516,382
228201.248.192.0/18201.248.192.1 to 201.248.255.254201.248.255.25516,382
229201.249.0.0/18201.249.0.1 to 201.249.63.254201.249.63.25516,382
230201.249.64.0/18201.249.64.1 to 201.249.127.254201.249.127.25516,382
231201.249.128.0/18201.249.128.1 to 201.249.191.254201.249.191.25516,382
232201.249.192.0/18201.249.192.1 to 201.249.255.254201.249.255.25516,382
233201.250.0.0/18201.250.0.1 to 201.250.63.254201.250.63.25516,382
234201.250.64.0/18201.250.64.1 to 201.250.127.254201.250.127.25516,382
235201.250.128.0/18201.250.128.1 to 201.250.191.254201.250.191.25516,382
236201.250.192.0/18201.250.192.1 to 201.250.255.254201.250.255.25516,382
237201.251.0.0/18201.251.0.1 to 201.251.63.254201.251.63.25516,382
238201.251.64.0/18201.251.64.1 to 201.251.127.254201.251.127.25516,382
239201.251.128.0/18201.251.128.1 to 201.251.191.254201.251.191.25516,382
240201.251.192.0/18201.251.192.1 to 201.251.255.254201.251.255.25516,382
241201.252.0.0/18201.252.0.1 to 201.252.63.254201.252.63.25516,382
242201.252.64.0/18201.252.64.1 to 201.252.127.254201.252.127.25516,382
243201.252.128.0/18201.252.128.1 to 201.252.191.254201.252.191.25516,382
244201.252.192.0/18201.252.192.1 to 201.252.255.254201.252.255.25516,382
245201.253.0.0/18201.253.0.1 to 201.253.63.254201.253.63.25516,382
246201.253.64.0/18201.253.64.1 to 201.253.127.254201.253.127.25516,382
247201.253.128.0/18201.253.128.1 to 201.253.191.254201.253.191.25516,382
248201.253.192.0/18201.253.192.1 to 201.253.255.254201.253.255.25516,382
249201.254.0.0/18201.254.0.1 to 201.254.63.254201.254.63.25516,382
250201.254.64.0/18201.254.64.1 to 201.254.127.254201.254.127.25516,382
251201.254.128.0/18201.254.128.1 to 201.254.191.254201.254.191.25516,382
252201.254.192.0/18201.254.192.1 to 201.254.255.254201.254.255.25516,382
253201.255.0.0/18201.255.0.1 to 201.255.63.254201.255.63.25516,382
254201.255.64.0/18201.255.64.1 to 201.255.127.254201.255.127.25516,382
255201.255.128.0/18201.255.128.1 to 201.255.191.254201.255.191.25516,382
256201.255.192.0/18201.255.192.1 to 201.255.255.254201.255.255.25516,382

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.