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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.

Network200.166.0.0/16
Usable hosts65,534
Subnet mask255.255.0.0
Addresses65,536
Network address
200.166.0.0
Broadcast address
200.166.255.255
First usable
200.166.0.1
Last usable
200.166.255.254
Usable hosts
65,534 (65,536 less the network and broadcast addresses)
Subnet mask
255.255.0.0
Wildcard mask
0.0.255.255 (Cisco ACLs, OSPF)
Prefix length
/16
Type
Public public
Old class
C (default /24)
As numbers
Hex C8A60000 · Integer 3366322176 to 3366387711
Reverse DNS zone
166.200.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11001000.10100110..00000000.00000000200.166.0.0
Subnet mask11111111.11111111..00000000.00000000255.255.0.0
Network11001000.10100110..00000000.00000000200.166.0.0
Broadcast11001000.10100110..11111111.11111111200.166.255.255
Split into smaller subnets/24
/17 (2)/18 (4)/19 (8)/20 (16)/21 (32)/22 (64)/23 (128)/24 (256)/25 (512)/26 (1,024)/27 (2,048)/28 (4,096)

200.166.0.0/16 makes 256 subnets of /24.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1200.166.0.0/24200.166.0.1 to 200.166.0.254200.166.0.255254
2200.166.1.0/24200.166.1.1 to 200.166.1.254200.166.1.255254
3200.166.2.0/24200.166.2.1 to 200.166.2.254200.166.2.255254
4200.166.3.0/24200.166.3.1 to 200.166.3.254200.166.3.255254
5200.166.4.0/24200.166.4.1 to 200.166.4.254200.166.4.255254
6200.166.5.0/24200.166.5.1 to 200.166.5.254200.166.5.255254
7200.166.6.0/24200.166.6.1 to 200.166.6.254200.166.6.255254
8200.166.7.0/24200.166.7.1 to 200.166.7.254200.166.7.255254
9200.166.8.0/24200.166.8.1 to 200.166.8.254200.166.8.255254
10200.166.9.0/24200.166.9.1 to 200.166.9.254200.166.9.255254
11200.166.10.0/24200.166.10.1 to 200.166.10.254200.166.10.255254
12200.166.11.0/24200.166.11.1 to 200.166.11.254200.166.11.255254
13200.166.12.0/24200.166.12.1 to 200.166.12.254200.166.12.255254
14200.166.13.0/24200.166.13.1 to 200.166.13.254200.166.13.255254
15200.166.14.0/24200.166.14.1 to 200.166.14.254200.166.14.255254
16200.166.15.0/24200.166.15.1 to 200.166.15.254200.166.15.255254
17200.166.16.0/24200.166.16.1 to 200.166.16.254200.166.16.255254
18200.166.17.0/24200.166.17.1 to 200.166.17.254200.166.17.255254
19200.166.18.0/24200.166.18.1 to 200.166.18.254200.166.18.255254
20200.166.19.0/24200.166.19.1 to 200.166.19.254200.166.19.255254
21200.166.20.0/24200.166.20.1 to 200.166.20.254200.166.20.255254
22200.166.21.0/24200.166.21.1 to 200.166.21.254200.166.21.255254
23200.166.22.0/24200.166.22.1 to 200.166.22.254200.166.22.255254
24200.166.23.0/24200.166.23.1 to 200.166.23.254200.166.23.255254
25200.166.24.0/24200.166.24.1 to 200.166.24.254200.166.24.255254
26200.166.25.0/24200.166.25.1 to 200.166.25.254200.166.25.255254
27200.166.26.0/24200.166.26.1 to 200.166.26.254200.166.26.255254
28200.166.27.0/24200.166.27.1 to 200.166.27.254200.166.27.255254
29200.166.28.0/24200.166.28.1 to 200.166.28.254200.166.28.255254
30200.166.29.0/24200.166.29.1 to 200.166.29.254200.166.29.255254
31200.166.30.0/24200.166.30.1 to 200.166.30.254200.166.30.255254
32200.166.31.0/24200.166.31.1 to 200.166.31.254200.166.31.255254
33200.166.32.0/24200.166.32.1 to 200.166.32.254200.166.32.255254
34200.166.33.0/24200.166.33.1 to 200.166.33.254200.166.33.255254
35200.166.34.0/24200.166.34.1 to 200.166.34.254200.166.34.255254
36200.166.35.0/24200.166.35.1 to 200.166.35.254200.166.35.255254
37200.166.36.0/24200.166.36.1 to 200.166.36.254200.166.36.255254
38200.166.37.0/24200.166.37.1 to 200.166.37.254200.166.37.255254
39200.166.38.0/24200.166.38.1 to 200.166.38.254200.166.38.255254
40200.166.39.0/24200.166.39.1 to 200.166.39.254200.166.39.255254
41200.166.40.0/24200.166.40.1 to 200.166.40.254200.166.40.255254
42200.166.41.0/24200.166.41.1 to 200.166.41.254200.166.41.255254
43200.166.42.0/24200.166.42.1 to 200.166.42.254200.166.42.255254
44200.166.43.0/24200.166.43.1 to 200.166.43.254200.166.43.255254
45200.166.44.0/24200.166.44.1 to 200.166.44.254200.166.44.255254
46200.166.45.0/24200.166.45.1 to 200.166.45.254200.166.45.255254
47200.166.46.0/24200.166.46.1 to 200.166.46.254200.166.46.255254
48200.166.47.0/24200.166.47.1 to 200.166.47.254200.166.47.255254
49200.166.48.0/24200.166.48.1 to 200.166.48.254200.166.48.255254
50200.166.49.0/24200.166.49.1 to 200.166.49.254200.166.49.255254
51200.166.50.0/24200.166.50.1 to 200.166.50.254200.166.50.255254
52200.166.51.0/24200.166.51.1 to 200.166.51.254200.166.51.255254
53200.166.52.0/24200.166.52.1 to 200.166.52.254200.166.52.255254
54200.166.53.0/24200.166.53.1 to 200.166.53.254200.166.53.255254
55200.166.54.0/24200.166.54.1 to 200.166.54.254200.166.54.255254
56200.166.55.0/24200.166.55.1 to 200.166.55.254200.166.55.255254
57200.166.56.0/24200.166.56.1 to 200.166.56.254200.166.56.255254
58200.166.57.0/24200.166.57.1 to 200.166.57.254200.166.57.255254
59200.166.58.0/24200.166.58.1 to 200.166.58.254200.166.58.255254
60200.166.59.0/24200.166.59.1 to 200.166.59.254200.166.59.255254
61200.166.60.0/24200.166.60.1 to 200.166.60.254200.166.60.255254
62200.166.61.0/24200.166.61.1 to 200.166.61.254200.166.61.255254
63200.166.62.0/24200.166.62.1 to 200.166.62.254200.166.62.255254
64200.166.63.0/24200.166.63.1 to 200.166.63.254200.166.63.255254
65200.166.64.0/24200.166.64.1 to 200.166.64.254200.166.64.255254
66200.166.65.0/24200.166.65.1 to 200.166.65.254200.166.65.255254
67200.166.66.0/24200.166.66.1 to 200.166.66.254200.166.66.255254
68200.166.67.0/24200.166.67.1 to 200.166.67.254200.166.67.255254
69200.166.68.0/24200.166.68.1 to 200.166.68.254200.166.68.255254
70200.166.69.0/24200.166.69.1 to 200.166.69.254200.166.69.255254
71200.166.70.0/24200.166.70.1 to 200.166.70.254200.166.70.255254
72200.166.71.0/24200.166.71.1 to 200.166.71.254200.166.71.255254
73200.166.72.0/24200.166.72.1 to 200.166.72.254200.166.72.255254
74200.166.73.0/24200.166.73.1 to 200.166.73.254200.166.73.255254
75200.166.74.0/24200.166.74.1 to 200.166.74.254200.166.74.255254
76200.166.75.0/24200.166.75.1 to 200.166.75.254200.166.75.255254
77200.166.76.0/24200.166.76.1 to 200.166.76.254200.166.76.255254
78200.166.77.0/24200.166.77.1 to 200.166.77.254200.166.77.255254
79200.166.78.0/24200.166.78.1 to 200.166.78.254200.166.78.255254
80200.166.79.0/24200.166.79.1 to 200.166.79.254200.166.79.255254
81200.166.80.0/24200.166.80.1 to 200.166.80.254200.166.80.255254
82200.166.81.0/24200.166.81.1 to 200.166.81.254200.166.81.255254
83200.166.82.0/24200.166.82.1 to 200.166.82.254200.166.82.255254
84200.166.83.0/24200.166.83.1 to 200.166.83.254200.166.83.255254
85200.166.84.0/24200.166.84.1 to 200.166.84.254200.166.84.255254
86200.166.85.0/24200.166.85.1 to 200.166.85.254200.166.85.255254
87200.166.86.0/24200.166.86.1 to 200.166.86.254200.166.86.255254
88200.166.87.0/24200.166.87.1 to 200.166.87.254200.166.87.255254
89200.166.88.0/24200.166.88.1 to 200.166.88.254200.166.88.255254
90200.166.89.0/24200.166.89.1 to 200.166.89.254200.166.89.255254
91200.166.90.0/24200.166.90.1 to 200.166.90.254200.166.90.255254
92200.166.91.0/24200.166.91.1 to 200.166.91.254200.166.91.255254
93200.166.92.0/24200.166.92.1 to 200.166.92.254200.166.92.255254
94200.166.93.0/24200.166.93.1 to 200.166.93.254200.166.93.255254
95200.166.94.0/24200.166.94.1 to 200.166.94.254200.166.94.255254
96200.166.95.0/24200.166.95.1 to 200.166.95.254200.166.95.255254
97200.166.96.0/24200.166.96.1 to 200.166.96.254200.166.96.255254
98200.166.97.0/24200.166.97.1 to 200.166.97.254200.166.97.255254
99200.166.98.0/24200.166.98.1 to 200.166.98.254200.166.98.255254
100200.166.99.0/24200.166.99.1 to 200.166.99.254200.166.99.255254
101200.166.100.0/24200.166.100.1 to 200.166.100.254200.166.100.255254
102200.166.101.0/24200.166.101.1 to 200.166.101.254200.166.101.255254
103200.166.102.0/24200.166.102.1 to 200.166.102.254200.166.102.255254
104200.166.103.0/24200.166.103.1 to 200.166.103.254200.166.103.255254
105200.166.104.0/24200.166.104.1 to 200.166.104.254200.166.104.255254
106200.166.105.0/24200.166.105.1 to 200.166.105.254200.166.105.255254
107200.166.106.0/24200.166.106.1 to 200.166.106.254200.166.106.255254
108200.166.107.0/24200.166.107.1 to 200.166.107.254200.166.107.255254
109200.166.108.0/24200.166.108.1 to 200.166.108.254200.166.108.255254
110200.166.109.0/24200.166.109.1 to 200.166.109.254200.166.109.255254
111200.166.110.0/24200.166.110.1 to 200.166.110.254200.166.110.255254
112200.166.111.0/24200.166.111.1 to 200.166.111.254200.166.111.255254
113200.166.112.0/24200.166.112.1 to 200.166.112.254200.166.112.255254
114200.166.113.0/24200.166.113.1 to 200.166.113.254200.166.113.255254
115200.166.114.0/24200.166.114.1 to 200.166.114.254200.166.114.255254
116200.166.115.0/24200.166.115.1 to 200.166.115.254200.166.115.255254
117200.166.116.0/24200.166.116.1 to 200.166.116.254200.166.116.255254
118200.166.117.0/24200.166.117.1 to 200.166.117.254200.166.117.255254
119200.166.118.0/24200.166.118.1 to 200.166.118.254200.166.118.255254
120200.166.119.0/24200.166.119.1 to 200.166.119.254200.166.119.255254
121200.166.120.0/24200.166.120.1 to 200.166.120.254200.166.120.255254
122200.166.121.0/24200.166.121.1 to 200.166.121.254200.166.121.255254
123200.166.122.0/24200.166.122.1 to 200.166.122.254200.166.122.255254
124200.166.123.0/24200.166.123.1 to 200.166.123.254200.166.123.255254
125200.166.124.0/24200.166.124.1 to 200.166.124.254200.166.124.255254
126200.166.125.0/24200.166.125.1 to 200.166.125.254200.166.125.255254
127200.166.126.0/24200.166.126.1 to 200.166.126.254200.166.126.255254
128200.166.127.0/24200.166.127.1 to 200.166.127.254200.166.127.255254
129200.166.128.0/24200.166.128.1 to 200.166.128.254200.166.128.255254
130200.166.129.0/24200.166.129.1 to 200.166.129.254200.166.129.255254
131200.166.130.0/24200.166.130.1 to 200.166.130.254200.166.130.255254
132200.166.131.0/24200.166.131.1 to 200.166.131.254200.166.131.255254
133200.166.132.0/24200.166.132.1 to 200.166.132.254200.166.132.255254
134200.166.133.0/24200.166.133.1 to 200.166.133.254200.166.133.255254
135200.166.134.0/24200.166.134.1 to 200.166.134.254200.166.134.255254
136200.166.135.0/24200.166.135.1 to 200.166.135.254200.166.135.255254
137200.166.136.0/24200.166.136.1 to 200.166.136.254200.166.136.255254
138200.166.137.0/24200.166.137.1 to 200.166.137.254200.166.137.255254
139200.166.138.0/24200.166.138.1 to 200.166.138.254200.166.138.255254
140200.166.139.0/24200.166.139.1 to 200.166.139.254200.166.139.255254
141200.166.140.0/24200.166.140.1 to 200.166.140.254200.166.140.255254
142200.166.141.0/24200.166.141.1 to 200.166.141.254200.166.141.255254
143200.166.142.0/24200.166.142.1 to 200.166.142.254200.166.142.255254
144200.166.143.0/24200.166.143.1 to 200.166.143.254200.166.143.255254
145200.166.144.0/24200.166.144.1 to 200.166.144.254200.166.144.255254
146200.166.145.0/24200.166.145.1 to 200.166.145.254200.166.145.255254
147200.166.146.0/24200.166.146.1 to 200.166.146.254200.166.146.255254
148200.166.147.0/24200.166.147.1 to 200.166.147.254200.166.147.255254
149200.166.148.0/24200.166.148.1 to 200.166.148.254200.166.148.255254
150200.166.149.0/24200.166.149.1 to 200.166.149.254200.166.149.255254
151200.166.150.0/24200.166.150.1 to 200.166.150.254200.166.150.255254
152200.166.151.0/24200.166.151.1 to 200.166.151.254200.166.151.255254
153200.166.152.0/24200.166.152.1 to 200.166.152.254200.166.152.255254
154200.166.153.0/24200.166.153.1 to 200.166.153.254200.166.153.255254
155200.166.154.0/24200.166.154.1 to 200.166.154.254200.166.154.255254
156200.166.155.0/24200.166.155.1 to 200.166.155.254200.166.155.255254
157200.166.156.0/24200.166.156.1 to 200.166.156.254200.166.156.255254
158200.166.157.0/24200.166.157.1 to 200.166.157.254200.166.157.255254
159200.166.158.0/24200.166.158.1 to 200.166.158.254200.166.158.255254
160200.166.159.0/24200.166.159.1 to 200.166.159.254200.166.159.255254
161200.166.160.0/24200.166.160.1 to 200.166.160.254200.166.160.255254
162200.166.161.0/24200.166.161.1 to 200.166.161.254200.166.161.255254
163200.166.162.0/24200.166.162.1 to 200.166.162.254200.166.162.255254
164200.166.163.0/24200.166.163.1 to 200.166.163.254200.166.163.255254
165200.166.164.0/24200.166.164.1 to 200.166.164.254200.166.164.255254
166200.166.165.0/24200.166.165.1 to 200.166.165.254200.166.165.255254
167200.166.166.0/24200.166.166.1 to 200.166.166.254200.166.166.255254
168200.166.167.0/24200.166.167.1 to 200.166.167.254200.166.167.255254
169200.166.168.0/24200.166.168.1 to 200.166.168.254200.166.168.255254
170200.166.169.0/24200.166.169.1 to 200.166.169.254200.166.169.255254
171200.166.170.0/24200.166.170.1 to 200.166.170.254200.166.170.255254
172200.166.171.0/24200.166.171.1 to 200.166.171.254200.166.171.255254
173200.166.172.0/24200.166.172.1 to 200.166.172.254200.166.172.255254
174200.166.173.0/24200.166.173.1 to 200.166.173.254200.166.173.255254
175200.166.174.0/24200.166.174.1 to 200.166.174.254200.166.174.255254
176200.166.175.0/24200.166.175.1 to 200.166.175.254200.166.175.255254
177200.166.176.0/24200.166.176.1 to 200.166.176.254200.166.176.255254
178200.166.177.0/24200.166.177.1 to 200.166.177.254200.166.177.255254
179200.166.178.0/24200.166.178.1 to 200.166.178.254200.166.178.255254
180200.166.179.0/24200.166.179.1 to 200.166.179.254200.166.179.255254
181200.166.180.0/24200.166.180.1 to 200.166.180.254200.166.180.255254
182200.166.181.0/24200.166.181.1 to 200.166.181.254200.166.181.255254
183200.166.182.0/24200.166.182.1 to 200.166.182.254200.166.182.255254
184200.166.183.0/24200.166.183.1 to 200.166.183.254200.166.183.255254
185200.166.184.0/24200.166.184.1 to 200.166.184.254200.166.184.255254
186200.166.185.0/24200.166.185.1 to 200.166.185.254200.166.185.255254
187200.166.186.0/24200.166.186.1 to 200.166.186.254200.166.186.255254
188200.166.187.0/24200.166.187.1 to 200.166.187.254200.166.187.255254
189200.166.188.0/24200.166.188.1 to 200.166.188.254200.166.188.255254
190200.166.189.0/24200.166.189.1 to 200.166.189.254200.166.189.255254
191200.166.190.0/24200.166.190.1 to 200.166.190.254200.166.190.255254
192200.166.191.0/24200.166.191.1 to 200.166.191.254200.166.191.255254
193200.166.192.0/24200.166.192.1 to 200.166.192.254200.166.192.255254
194200.166.193.0/24200.166.193.1 to 200.166.193.254200.166.193.255254
195200.166.194.0/24200.166.194.1 to 200.166.194.254200.166.194.255254
196200.166.195.0/24200.166.195.1 to 200.166.195.254200.166.195.255254
197200.166.196.0/24200.166.196.1 to 200.166.196.254200.166.196.255254
198200.166.197.0/24200.166.197.1 to 200.166.197.254200.166.197.255254
199200.166.198.0/24200.166.198.1 to 200.166.198.254200.166.198.255254
200200.166.199.0/24200.166.199.1 to 200.166.199.254200.166.199.255254
201200.166.200.0/24200.166.200.1 to 200.166.200.254200.166.200.255254
202200.166.201.0/24200.166.201.1 to 200.166.201.254200.166.201.255254
203200.166.202.0/24200.166.202.1 to 200.166.202.254200.166.202.255254
204200.166.203.0/24200.166.203.1 to 200.166.203.254200.166.203.255254
205200.166.204.0/24200.166.204.1 to 200.166.204.254200.166.204.255254
206200.166.205.0/24200.166.205.1 to 200.166.205.254200.166.205.255254
207200.166.206.0/24200.166.206.1 to 200.166.206.254200.166.206.255254
208200.166.207.0/24200.166.207.1 to 200.166.207.254200.166.207.255254
209200.166.208.0/24200.166.208.1 to 200.166.208.254200.166.208.255254
210200.166.209.0/24200.166.209.1 to 200.166.209.254200.166.209.255254
211200.166.210.0/24200.166.210.1 to 200.166.210.254200.166.210.255254
212200.166.211.0/24200.166.211.1 to 200.166.211.254200.166.211.255254
213200.166.212.0/24200.166.212.1 to 200.166.212.254200.166.212.255254
214200.166.213.0/24200.166.213.1 to 200.166.213.254200.166.213.255254
215200.166.214.0/24200.166.214.1 to 200.166.214.254200.166.214.255254
216200.166.215.0/24200.166.215.1 to 200.166.215.254200.166.215.255254
217200.166.216.0/24200.166.216.1 to 200.166.216.254200.166.216.255254
218200.166.217.0/24200.166.217.1 to 200.166.217.254200.166.217.255254
219200.166.218.0/24200.166.218.1 to 200.166.218.254200.166.218.255254
220200.166.219.0/24200.166.219.1 to 200.166.219.254200.166.219.255254
221200.166.220.0/24200.166.220.1 to 200.166.220.254200.166.220.255254
222200.166.221.0/24200.166.221.1 to 200.166.221.254200.166.221.255254
223200.166.222.0/24200.166.222.1 to 200.166.222.254200.166.222.255254
224200.166.223.0/24200.166.223.1 to 200.166.223.254200.166.223.255254
225200.166.224.0/24200.166.224.1 to 200.166.224.254200.166.224.255254
226200.166.225.0/24200.166.225.1 to 200.166.225.254200.166.225.255254
227200.166.226.0/24200.166.226.1 to 200.166.226.254200.166.226.255254
228200.166.227.0/24200.166.227.1 to 200.166.227.254200.166.227.255254
229200.166.228.0/24200.166.228.1 to 200.166.228.254200.166.228.255254
230200.166.229.0/24200.166.229.1 to 200.166.229.254200.166.229.255254
231200.166.230.0/24200.166.230.1 to 200.166.230.254200.166.230.255254
232200.166.231.0/24200.166.231.1 to 200.166.231.254200.166.231.255254
233200.166.232.0/24200.166.232.1 to 200.166.232.254200.166.232.255254
234200.166.233.0/24200.166.233.1 to 200.166.233.254200.166.233.255254
235200.166.234.0/24200.166.234.1 to 200.166.234.254200.166.234.255254
236200.166.235.0/24200.166.235.1 to 200.166.235.254200.166.235.255254
237200.166.236.0/24200.166.236.1 to 200.166.236.254200.166.236.255254
238200.166.237.0/24200.166.237.1 to 200.166.237.254200.166.237.255254
239200.166.238.0/24200.166.238.1 to 200.166.238.254200.166.238.255254
240200.166.239.0/24200.166.239.1 to 200.166.239.254200.166.239.255254
241200.166.240.0/24200.166.240.1 to 200.166.240.254200.166.240.255254
242200.166.241.0/24200.166.241.1 to 200.166.241.254200.166.241.255254
243200.166.242.0/24200.166.242.1 to 200.166.242.254200.166.242.255254
244200.166.243.0/24200.166.243.1 to 200.166.243.254200.166.243.255254
245200.166.244.0/24200.166.244.1 to 200.166.244.254200.166.244.255254
246200.166.245.0/24200.166.245.1 to 200.166.245.254200.166.245.255254
247200.166.246.0/24200.166.246.1 to 200.166.246.254200.166.246.255254
248200.166.247.0/24200.166.247.1 to 200.166.247.254200.166.247.255254
249200.166.248.0/24200.166.248.1 to 200.166.248.254200.166.248.255254
250200.166.249.0/24200.166.249.1 to 200.166.249.254200.166.249.255254
251200.166.250.0/24200.166.250.1 to 200.166.250.254200.166.250.255254
252200.166.251.0/24200.166.251.1 to 200.166.251.254200.166.251.255254
253200.166.252.0/24200.166.252.1 to 200.166.252.254200.166.252.255254
254200.166.253.0/24200.166.253.1 to 200.166.253.254200.166.253.255254
255200.166.254.0/24200.166.254.1 to 200.166.254.254200.166.254.255254
256200.166.255.0/24200.166.255.1 to 200.166.255.254200.166.255.255254

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.