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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.

Network201.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
201.0.0.0
Broadcast address
201.255.255.255
First usable
201.0.0.1
Last usable
201.255.255.254
Usable hosts
16,777,214 (16,777,216 less the network and broadcast addresses)
Subnet mask
255.0.0.0
Wildcard mask
0.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/8
Type
Public public
Old class
C (default /24)
As numbers
Hex C9000000 · Integer 3372220416 to 3388997631
Reverse DNS zone
201.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11001001..00000000.00000000.00000000201.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network11001001..00000000.00000000.00000000201.0.0.0
Broadcast11001001..11111111.11111111.11111111201.255.255.255
Split into smaller subnets/16
/9 (2)/10 (4)/11 (8)/12 (16)/13 (32)/14 (64)/15 (128)/16 (256)/17 (512)/18 (1,024)/19 (2,048)/20 (4,096)

201.0.0.0/8 makes 256 subnets of /16.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1201.0.0.0/16201.0.0.1 to 201.0.255.254201.0.255.25565,534
2201.1.0.0/16201.1.0.1 to 201.1.255.254201.1.255.25565,534
3201.2.0.0/16201.2.0.1 to 201.2.255.254201.2.255.25565,534
4201.3.0.0/16201.3.0.1 to 201.3.255.254201.3.255.25565,534
5201.4.0.0/16201.4.0.1 to 201.4.255.254201.4.255.25565,534
6201.5.0.0/16201.5.0.1 to 201.5.255.254201.5.255.25565,534
7201.6.0.0/16201.6.0.1 to 201.6.255.254201.6.255.25565,534
8201.7.0.0/16201.7.0.1 to 201.7.255.254201.7.255.25565,534
9201.8.0.0/16201.8.0.1 to 201.8.255.254201.8.255.25565,534
10201.9.0.0/16201.9.0.1 to 201.9.255.254201.9.255.25565,534
11201.10.0.0/16201.10.0.1 to 201.10.255.254201.10.255.25565,534
12201.11.0.0/16201.11.0.1 to 201.11.255.254201.11.255.25565,534
13201.12.0.0/16201.12.0.1 to 201.12.255.254201.12.255.25565,534
14201.13.0.0/16201.13.0.1 to 201.13.255.254201.13.255.25565,534
15201.14.0.0/16201.14.0.1 to 201.14.255.254201.14.255.25565,534
16201.15.0.0/16201.15.0.1 to 201.15.255.254201.15.255.25565,534
17201.16.0.0/16201.16.0.1 to 201.16.255.254201.16.255.25565,534
18201.17.0.0/16201.17.0.1 to 201.17.255.254201.17.255.25565,534
19201.18.0.0/16201.18.0.1 to 201.18.255.254201.18.255.25565,534
20201.19.0.0/16201.19.0.1 to 201.19.255.254201.19.255.25565,534
21201.20.0.0/16201.20.0.1 to 201.20.255.254201.20.255.25565,534
22201.21.0.0/16201.21.0.1 to 201.21.255.254201.21.255.25565,534
23201.22.0.0/16201.22.0.1 to 201.22.255.254201.22.255.25565,534
24201.23.0.0/16201.23.0.1 to 201.23.255.254201.23.255.25565,534
25201.24.0.0/16201.24.0.1 to 201.24.255.254201.24.255.25565,534
26201.25.0.0/16201.25.0.1 to 201.25.255.254201.25.255.25565,534
27201.26.0.0/16201.26.0.1 to 201.26.255.254201.26.255.25565,534
28201.27.0.0/16201.27.0.1 to 201.27.255.254201.27.255.25565,534
29201.28.0.0/16201.28.0.1 to 201.28.255.254201.28.255.25565,534
30201.29.0.0/16201.29.0.1 to 201.29.255.254201.29.255.25565,534
31201.30.0.0/16201.30.0.1 to 201.30.255.254201.30.255.25565,534
32201.31.0.0/16201.31.0.1 to 201.31.255.254201.31.255.25565,534
33201.32.0.0/16201.32.0.1 to 201.32.255.254201.32.255.25565,534
34201.33.0.0/16201.33.0.1 to 201.33.255.254201.33.255.25565,534
35201.34.0.0/16201.34.0.1 to 201.34.255.254201.34.255.25565,534
36201.35.0.0/16201.35.0.1 to 201.35.255.254201.35.255.25565,534
37201.36.0.0/16201.36.0.1 to 201.36.255.254201.36.255.25565,534
38201.37.0.0/16201.37.0.1 to 201.37.255.254201.37.255.25565,534
39201.38.0.0/16201.38.0.1 to 201.38.255.254201.38.255.25565,534
40201.39.0.0/16201.39.0.1 to 201.39.255.254201.39.255.25565,534
41201.40.0.0/16201.40.0.1 to 201.40.255.254201.40.255.25565,534
42201.41.0.0/16201.41.0.1 to 201.41.255.254201.41.255.25565,534
43201.42.0.0/16201.42.0.1 to 201.42.255.254201.42.255.25565,534
44201.43.0.0/16201.43.0.1 to 201.43.255.254201.43.255.25565,534
45201.44.0.0/16201.44.0.1 to 201.44.255.254201.44.255.25565,534
46201.45.0.0/16201.45.0.1 to 201.45.255.254201.45.255.25565,534
47201.46.0.0/16201.46.0.1 to 201.46.255.254201.46.255.25565,534
48201.47.0.0/16201.47.0.1 to 201.47.255.254201.47.255.25565,534
49201.48.0.0/16201.48.0.1 to 201.48.255.254201.48.255.25565,534
50201.49.0.0/16201.49.0.1 to 201.49.255.254201.49.255.25565,534
51201.50.0.0/16201.50.0.1 to 201.50.255.254201.50.255.25565,534
52201.51.0.0/16201.51.0.1 to 201.51.255.254201.51.255.25565,534
53201.52.0.0/16201.52.0.1 to 201.52.255.254201.52.255.25565,534
54201.53.0.0/16201.53.0.1 to 201.53.255.254201.53.255.25565,534
55201.54.0.0/16201.54.0.1 to 201.54.255.254201.54.255.25565,534
56201.55.0.0/16201.55.0.1 to 201.55.255.254201.55.255.25565,534
57201.56.0.0/16201.56.0.1 to 201.56.255.254201.56.255.25565,534
58201.57.0.0/16201.57.0.1 to 201.57.255.254201.57.255.25565,534
59201.58.0.0/16201.58.0.1 to 201.58.255.254201.58.255.25565,534
60201.59.0.0/16201.59.0.1 to 201.59.255.254201.59.255.25565,534
61201.60.0.0/16201.60.0.1 to 201.60.255.254201.60.255.25565,534
62201.61.0.0/16201.61.0.1 to 201.61.255.254201.61.255.25565,534
63201.62.0.0/16201.62.0.1 to 201.62.255.254201.62.255.25565,534
64201.63.0.0/16201.63.0.1 to 201.63.255.254201.63.255.25565,534
65201.64.0.0/16201.64.0.1 to 201.64.255.254201.64.255.25565,534
66201.65.0.0/16201.65.0.1 to 201.65.255.254201.65.255.25565,534
67201.66.0.0/16201.66.0.1 to 201.66.255.254201.66.255.25565,534
68201.67.0.0/16201.67.0.1 to 201.67.255.254201.67.255.25565,534
69201.68.0.0/16201.68.0.1 to 201.68.255.254201.68.255.25565,534
70201.69.0.0/16201.69.0.1 to 201.69.255.254201.69.255.25565,534
71201.70.0.0/16201.70.0.1 to 201.70.255.254201.70.255.25565,534
72201.71.0.0/16201.71.0.1 to 201.71.255.254201.71.255.25565,534
73201.72.0.0/16201.72.0.1 to 201.72.255.254201.72.255.25565,534
74201.73.0.0/16201.73.0.1 to 201.73.255.254201.73.255.25565,534
75201.74.0.0/16201.74.0.1 to 201.74.255.254201.74.255.25565,534
76201.75.0.0/16201.75.0.1 to 201.75.255.254201.75.255.25565,534
77201.76.0.0/16201.76.0.1 to 201.76.255.254201.76.255.25565,534
78201.77.0.0/16201.77.0.1 to 201.77.255.254201.77.255.25565,534
79201.78.0.0/16201.78.0.1 to 201.78.255.254201.78.255.25565,534
80201.79.0.0/16201.79.0.1 to 201.79.255.254201.79.255.25565,534
81201.80.0.0/16201.80.0.1 to 201.80.255.254201.80.255.25565,534
82201.81.0.0/16201.81.0.1 to 201.81.255.254201.81.255.25565,534
83201.82.0.0/16201.82.0.1 to 201.82.255.254201.82.255.25565,534
84201.83.0.0/16201.83.0.1 to 201.83.255.254201.83.255.25565,534
85201.84.0.0/16201.84.0.1 to 201.84.255.254201.84.255.25565,534
86201.85.0.0/16201.85.0.1 to 201.85.255.254201.85.255.25565,534
87201.86.0.0/16201.86.0.1 to 201.86.255.254201.86.255.25565,534
88201.87.0.0/16201.87.0.1 to 201.87.255.254201.87.255.25565,534
89201.88.0.0/16201.88.0.1 to 201.88.255.254201.88.255.25565,534
90201.89.0.0/16201.89.0.1 to 201.89.255.254201.89.255.25565,534
91201.90.0.0/16201.90.0.1 to 201.90.255.254201.90.255.25565,534
92201.91.0.0/16201.91.0.1 to 201.91.255.254201.91.255.25565,534
93201.92.0.0/16201.92.0.1 to 201.92.255.254201.92.255.25565,534
94201.93.0.0/16201.93.0.1 to 201.93.255.254201.93.255.25565,534
95201.94.0.0/16201.94.0.1 to 201.94.255.254201.94.255.25565,534
96201.95.0.0/16201.95.0.1 to 201.95.255.254201.95.255.25565,534
97201.96.0.0/16201.96.0.1 to 201.96.255.254201.96.255.25565,534
98201.97.0.0/16201.97.0.1 to 201.97.255.254201.97.255.25565,534
99201.98.0.0/16201.98.0.1 to 201.98.255.254201.98.255.25565,534
100201.99.0.0/16201.99.0.1 to 201.99.255.254201.99.255.25565,534
101201.100.0.0/16201.100.0.1 to 201.100.255.254201.100.255.25565,534
102201.101.0.0/16201.101.0.1 to 201.101.255.254201.101.255.25565,534
103201.102.0.0/16201.102.0.1 to 201.102.255.254201.102.255.25565,534
104201.103.0.0/16201.103.0.1 to 201.103.255.254201.103.255.25565,534
105201.104.0.0/16201.104.0.1 to 201.104.255.254201.104.255.25565,534
106201.105.0.0/16201.105.0.1 to 201.105.255.254201.105.255.25565,534
107201.106.0.0/16201.106.0.1 to 201.106.255.254201.106.255.25565,534
108201.107.0.0/16201.107.0.1 to 201.107.255.254201.107.255.25565,534
109201.108.0.0/16201.108.0.1 to 201.108.255.254201.108.255.25565,534
110201.109.0.0/16201.109.0.1 to 201.109.255.254201.109.255.25565,534
111201.110.0.0/16201.110.0.1 to 201.110.255.254201.110.255.25565,534
112201.111.0.0/16201.111.0.1 to 201.111.255.254201.111.255.25565,534
113201.112.0.0/16201.112.0.1 to 201.112.255.254201.112.255.25565,534
114201.113.0.0/16201.113.0.1 to 201.113.255.254201.113.255.25565,534
115201.114.0.0/16201.114.0.1 to 201.114.255.254201.114.255.25565,534
116201.115.0.0/16201.115.0.1 to 201.115.255.254201.115.255.25565,534
117201.116.0.0/16201.116.0.1 to 201.116.255.254201.116.255.25565,534
118201.117.0.0/16201.117.0.1 to 201.117.255.254201.117.255.25565,534
119201.118.0.0/16201.118.0.1 to 201.118.255.254201.118.255.25565,534
120201.119.0.0/16201.119.0.1 to 201.119.255.254201.119.255.25565,534
121201.120.0.0/16201.120.0.1 to 201.120.255.254201.120.255.25565,534
122201.121.0.0/16201.121.0.1 to 201.121.255.254201.121.255.25565,534
123201.122.0.0/16201.122.0.1 to 201.122.255.254201.122.255.25565,534
124201.123.0.0/16201.123.0.1 to 201.123.255.254201.123.255.25565,534
125201.124.0.0/16201.124.0.1 to 201.124.255.254201.124.255.25565,534
126201.125.0.0/16201.125.0.1 to 201.125.255.254201.125.255.25565,534
127201.126.0.0/16201.126.0.1 to 201.126.255.254201.126.255.25565,534
128201.127.0.0/16201.127.0.1 to 201.127.255.254201.127.255.25565,534
129201.128.0.0/16201.128.0.1 to 201.128.255.254201.128.255.25565,534
130201.129.0.0/16201.129.0.1 to 201.129.255.254201.129.255.25565,534
131201.130.0.0/16201.130.0.1 to 201.130.255.254201.130.255.25565,534
132201.131.0.0/16201.131.0.1 to 201.131.255.254201.131.255.25565,534
133201.132.0.0/16201.132.0.1 to 201.132.255.254201.132.255.25565,534
134201.133.0.0/16201.133.0.1 to 201.133.255.254201.133.255.25565,534
135201.134.0.0/16201.134.0.1 to 201.134.255.254201.134.255.25565,534
136201.135.0.0/16201.135.0.1 to 201.135.255.254201.135.255.25565,534
137201.136.0.0/16201.136.0.1 to 201.136.255.254201.136.255.25565,534
138201.137.0.0/16201.137.0.1 to 201.137.255.254201.137.255.25565,534
139201.138.0.0/16201.138.0.1 to 201.138.255.254201.138.255.25565,534
140201.139.0.0/16201.139.0.1 to 201.139.255.254201.139.255.25565,534
141201.140.0.0/16201.140.0.1 to 201.140.255.254201.140.255.25565,534
142201.141.0.0/16201.141.0.1 to 201.141.255.254201.141.255.25565,534
143201.142.0.0/16201.142.0.1 to 201.142.255.254201.142.255.25565,534
144201.143.0.0/16201.143.0.1 to 201.143.255.254201.143.255.25565,534
145201.144.0.0/16201.144.0.1 to 201.144.255.254201.144.255.25565,534
146201.145.0.0/16201.145.0.1 to 201.145.255.254201.145.255.25565,534
147201.146.0.0/16201.146.0.1 to 201.146.255.254201.146.255.25565,534
148201.147.0.0/16201.147.0.1 to 201.147.255.254201.147.255.25565,534
149201.148.0.0/16201.148.0.1 to 201.148.255.254201.148.255.25565,534
150201.149.0.0/16201.149.0.1 to 201.149.255.254201.149.255.25565,534
151201.150.0.0/16201.150.0.1 to 201.150.255.254201.150.255.25565,534
152201.151.0.0/16201.151.0.1 to 201.151.255.254201.151.255.25565,534
153201.152.0.0/16201.152.0.1 to 201.152.255.254201.152.255.25565,534
154201.153.0.0/16201.153.0.1 to 201.153.255.254201.153.255.25565,534
155201.154.0.0/16201.154.0.1 to 201.154.255.254201.154.255.25565,534
156201.155.0.0/16201.155.0.1 to 201.155.255.254201.155.255.25565,534
157201.156.0.0/16201.156.0.1 to 201.156.255.254201.156.255.25565,534
158201.157.0.0/16201.157.0.1 to 201.157.255.254201.157.255.25565,534
159201.158.0.0/16201.158.0.1 to 201.158.255.254201.158.255.25565,534
160201.159.0.0/16201.159.0.1 to 201.159.255.254201.159.255.25565,534
161201.160.0.0/16201.160.0.1 to 201.160.255.254201.160.255.25565,534
162201.161.0.0/16201.161.0.1 to 201.161.255.254201.161.255.25565,534
163201.162.0.0/16201.162.0.1 to 201.162.255.254201.162.255.25565,534
164201.163.0.0/16201.163.0.1 to 201.163.255.254201.163.255.25565,534
165201.164.0.0/16201.164.0.1 to 201.164.255.254201.164.255.25565,534
166201.165.0.0/16201.165.0.1 to 201.165.255.254201.165.255.25565,534
167201.166.0.0/16201.166.0.1 to 201.166.255.254201.166.255.25565,534
168201.167.0.0/16201.167.0.1 to 201.167.255.254201.167.255.25565,534
169201.168.0.0/16201.168.0.1 to 201.168.255.254201.168.255.25565,534
170201.169.0.0/16201.169.0.1 to 201.169.255.254201.169.255.25565,534
171201.170.0.0/16201.170.0.1 to 201.170.255.254201.170.255.25565,534
172201.171.0.0/16201.171.0.1 to 201.171.255.254201.171.255.25565,534
173201.172.0.0/16201.172.0.1 to 201.172.255.254201.172.255.25565,534
174201.173.0.0/16201.173.0.1 to 201.173.255.254201.173.255.25565,534
175201.174.0.0/16201.174.0.1 to 201.174.255.254201.174.255.25565,534
176201.175.0.0/16201.175.0.1 to 201.175.255.254201.175.255.25565,534
177201.176.0.0/16201.176.0.1 to 201.176.255.254201.176.255.25565,534
178201.177.0.0/16201.177.0.1 to 201.177.255.254201.177.255.25565,534
179201.178.0.0/16201.178.0.1 to 201.178.255.254201.178.255.25565,534
180201.179.0.0/16201.179.0.1 to 201.179.255.254201.179.255.25565,534
181201.180.0.0/16201.180.0.1 to 201.180.255.254201.180.255.25565,534
182201.181.0.0/16201.181.0.1 to 201.181.255.254201.181.255.25565,534
183201.182.0.0/16201.182.0.1 to 201.182.255.254201.182.255.25565,534
184201.183.0.0/16201.183.0.1 to 201.183.255.254201.183.255.25565,534
185201.184.0.0/16201.184.0.1 to 201.184.255.254201.184.255.25565,534
186201.185.0.0/16201.185.0.1 to 201.185.255.254201.185.255.25565,534
187201.186.0.0/16201.186.0.1 to 201.186.255.254201.186.255.25565,534
188201.187.0.0/16201.187.0.1 to 201.187.255.254201.187.255.25565,534
189201.188.0.0/16201.188.0.1 to 201.188.255.254201.188.255.25565,534
190201.189.0.0/16201.189.0.1 to 201.189.255.254201.189.255.25565,534
191201.190.0.0/16201.190.0.1 to 201.190.255.254201.190.255.25565,534
192201.191.0.0/16201.191.0.1 to 201.191.255.254201.191.255.25565,534
193201.192.0.0/16201.192.0.1 to 201.192.255.254201.192.255.25565,534
194201.193.0.0/16201.193.0.1 to 201.193.255.254201.193.255.25565,534
195201.194.0.0/16201.194.0.1 to 201.194.255.254201.194.255.25565,534
196201.195.0.0/16201.195.0.1 to 201.195.255.254201.195.255.25565,534
197201.196.0.0/16201.196.0.1 to 201.196.255.254201.196.255.25565,534
198201.197.0.0/16201.197.0.1 to 201.197.255.254201.197.255.25565,534
199201.198.0.0/16201.198.0.1 to 201.198.255.254201.198.255.25565,534
200201.199.0.0/16201.199.0.1 to 201.199.255.254201.199.255.25565,534
201201.200.0.0/16201.200.0.1 to 201.200.255.254201.200.255.25565,534
202201.201.0.0/16201.201.0.1 to 201.201.255.254201.201.255.25565,534
203201.202.0.0/16201.202.0.1 to 201.202.255.254201.202.255.25565,534
204201.203.0.0/16201.203.0.1 to 201.203.255.254201.203.255.25565,534
205201.204.0.0/16201.204.0.1 to 201.204.255.254201.204.255.25565,534
206201.205.0.0/16201.205.0.1 to 201.205.255.254201.205.255.25565,534
207201.206.0.0/16201.206.0.1 to 201.206.255.254201.206.255.25565,534
208201.207.0.0/16201.207.0.1 to 201.207.255.254201.207.255.25565,534
209201.208.0.0/16201.208.0.1 to 201.208.255.254201.208.255.25565,534
210201.209.0.0/16201.209.0.1 to 201.209.255.254201.209.255.25565,534
211201.210.0.0/16201.210.0.1 to 201.210.255.254201.210.255.25565,534
212201.211.0.0/16201.211.0.1 to 201.211.255.254201.211.255.25565,534
213201.212.0.0/16201.212.0.1 to 201.212.255.254201.212.255.25565,534
214201.213.0.0/16201.213.0.1 to 201.213.255.254201.213.255.25565,534
215201.214.0.0/16201.214.0.1 to 201.214.255.254201.214.255.25565,534
216201.215.0.0/16201.215.0.1 to 201.215.255.254201.215.255.25565,534
217201.216.0.0/16201.216.0.1 to 201.216.255.254201.216.255.25565,534
218201.217.0.0/16201.217.0.1 to 201.217.255.254201.217.255.25565,534
219201.218.0.0/16201.218.0.1 to 201.218.255.254201.218.255.25565,534
220201.219.0.0/16201.219.0.1 to 201.219.255.254201.219.255.25565,534
221201.220.0.0/16201.220.0.1 to 201.220.255.254201.220.255.25565,534
222201.221.0.0/16201.221.0.1 to 201.221.255.254201.221.255.25565,534
223201.222.0.0/16201.222.0.1 to 201.222.255.254201.222.255.25565,534
224201.223.0.0/16201.223.0.1 to 201.223.255.254201.223.255.25565,534
225201.224.0.0/16201.224.0.1 to 201.224.255.254201.224.255.25565,534
226201.225.0.0/16201.225.0.1 to 201.225.255.254201.225.255.25565,534
227201.226.0.0/16201.226.0.1 to 201.226.255.254201.226.255.25565,534
228201.227.0.0/16201.227.0.1 to 201.227.255.254201.227.255.25565,534
229201.228.0.0/16201.228.0.1 to 201.228.255.254201.228.255.25565,534
230201.229.0.0/16201.229.0.1 to 201.229.255.254201.229.255.25565,534
231201.230.0.0/16201.230.0.1 to 201.230.255.254201.230.255.25565,534
232201.231.0.0/16201.231.0.1 to 201.231.255.254201.231.255.25565,534
233201.232.0.0/16201.232.0.1 to 201.232.255.254201.232.255.25565,534
234201.233.0.0/16201.233.0.1 to 201.233.255.254201.233.255.25565,534
235201.234.0.0/16201.234.0.1 to 201.234.255.254201.234.255.25565,534
236201.235.0.0/16201.235.0.1 to 201.235.255.254201.235.255.25565,534
237201.236.0.0/16201.236.0.1 to 201.236.255.254201.236.255.25565,534
238201.237.0.0/16201.237.0.1 to 201.237.255.254201.237.255.25565,534
239201.238.0.0/16201.238.0.1 to 201.238.255.254201.238.255.25565,534
240201.239.0.0/16201.239.0.1 to 201.239.255.254201.239.255.25565,534
241201.240.0.0/16201.240.0.1 to 201.240.255.254201.240.255.25565,534
242201.241.0.0/16201.241.0.1 to 201.241.255.254201.241.255.25565,534
243201.242.0.0/16201.242.0.1 to 201.242.255.254201.242.255.25565,534
244201.243.0.0/16201.243.0.1 to 201.243.255.254201.243.255.25565,534
245201.244.0.0/16201.244.0.1 to 201.244.255.254201.244.255.25565,534
246201.245.0.0/16201.245.0.1 to 201.245.255.254201.245.255.25565,534
247201.246.0.0/16201.246.0.1 to 201.246.255.254201.246.255.25565,534
248201.247.0.0/16201.247.0.1 to 201.247.255.254201.247.255.25565,534
249201.248.0.0/16201.248.0.1 to 201.248.255.254201.248.255.25565,534
250201.249.0.0/16201.249.0.1 to 201.249.255.254201.249.255.25565,534
251201.250.0.0/16201.250.0.1 to 201.250.255.254201.250.255.25565,534
252201.251.0.0/16201.251.0.1 to 201.251.255.254201.251.255.25565,534
253201.252.0.0/16201.252.0.1 to 201.252.255.254201.252.255.25565,534
254201.253.0.0/16201.253.0.1 to 201.253.255.254201.253.255.25565,534
255201.254.0.0/16201.254.0.1 to 201.254.255.254201.254.255.25565,534
256201.255.0.0/16201.255.0.1 to 201.255.255.254201.255.255.25565,534

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.