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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.

Network141.64.0.0/12
Usable hosts1,048,574
Subnet mask255.240.0.0
Addresses1,048,576
Network address
141.64.0.0
Broadcast address
141.79.255.255
First usable
141.64.0.1
Last usable
141.79.255.254
Usable hosts
1,048,574 (1,048,576 less the network and broadcast addresses)
Subnet mask
255.240.0.0
Wildcard mask
0.15.255.255 (Cisco ACLs, OSPF)
Prefix length
/12
Type
Public public
Old class
B (default /16)
As numbers
Hex 8D400000 · Integer 2369781760 to 2370830335
Reverse DNS zones
64.141.in-addr.arpa
65.141.in-addr.arpa
66.141.in-addr.arpa
67.141.in-addr.arpa
68.141.in-addr.arpa
69.141.in-addr.arpa
70.141.in-addr.arpa
71.141.in-addr.arpa
72.141.in-addr.arpa
73.141.in-addr.arpa
74.141.in-addr.arpa
75.141.in-addr.arpa
76.141.in-addr.arpa
77.141.in-addr.arpa
78.141.in-addr.arpa
79.141.in-addr.arpa
/12 is not on a 8-bit boundary, so it takes 16 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10001101.01000000.00000000.00000000141.64.0.0
Subnet mask11111111.11110000.00000000.00000000255.240.0.0
Network10001101.01000000.00000000.00000000141.64.0.0
Broadcast10001101.01001111.11111111.11111111141.79.255.255
Split into smaller subnets/23
/13 (2)/14 (4)/15 (8)/16 (16)/17 (32)/18 (64)/19 (128)/20 (256)/21 (512)/22 (1,024)/23 (2,048)/24 (4,096)

141.64.0.0/12 makes 2,048 subnets of /23; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1141.64.0.0/23141.64.0.1 to 141.64.1.254141.64.1.255510
2141.64.2.0/23141.64.2.1 to 141.64.3.254141.64.3.255510
3141.64.4.0/23141.64.4.1 to 141.64.5.254141.64.5.255510
4141.64.6.0/23141.64.6.1 to 141.64.7.254141.64.7.255510
5141.64.8.0/23141.64.8.1 to 141.64.9.254141.64.9.255510
6141.64.10.0/23141.64.10.1 to 141.64.11.254141.64.11.255510
7141.64.12.0/23141.64.12.1 to 141.64.13.254141.64.13.255510
8141.64.14.0/23141.64.14.1 to 141.64.15.254141.64.15.255510
9141.64.16.0/23141.64.16.1 to 141.64.17.254141.64.17.255510
10141.64.18.0/23141.64.18.1 to 141.64.19.254141.64.19.255510
11141.64.20.0/23141.64.20.1 to 141.64.21.254141.64.21.255510
12141.64.22.0/23141.64.22.1 to 141.64.23.254141.64.23.255510
13141.64.24.0/23141.64.24.1 to 141.64.25.254141.64.25.255510
14141.64.26.0/23141.64.26.1 to 141.64.27.254141.64.27.255510
15141.64.28.0/23141.64.28.1 to 141.64.29.254141.64.29.255510
16141.64.30.0/23141.64.30.1 to 141.64.31.254141.64.31.255510
17141.64.32.0/23141.64.32.1 to 141.64.33.254141.64.33.255510
18141.64.34.0/23141.64.34.1 to 141.64.35.254141.64.35.255510
19141.64.36.0/23141.64.36.1 to 141.64.37.254141.64.37.255510
20141.64.38.0/23141.64.38.1 to 141.64.39.254141.64.39.255510
21141.64.40.0/23141.64.40.1 to 141.64.41.254141.64.41.255510
22141.64.42.0/23141.64.42.1 to 141.64.43.254141.64.43.255510
23141.64.44.0/23141.64.44.1 to 141.64.45.254141.64.45.255510
24141.64.46.0/23141.64.46.1 to 141.64.47.254141.64.47.255510
25141.64.48.0/23141.64.48.1 to 141.64.49.254141.64.49.255510
26141.64.50.0/23141.64.50.1 to 141.64.51.254141.64.51.255510
27141.64.52.0/23141.64.52.1 to 141.64.53.254141.64.53.255510
28141.64.54.0/23141.64.54.1 to 141.64.55.254141.64.55.255510
29141.64.56.0/23141.64.56.1 to 141.64.57.254141.64.57.255510
30141.64.58.0/23141.64.58.1 to 141.64.59.254141.64.59.255510
31141.64.60.0/23141.64.60.1 to 141.64.61.254141.64.61.255510
32141.64.62.0/23141.64.62.1 to 141.64.63.254141.64.63.255510
33141.64.64.0/23141.64.64.1 to 141.64.65.254141.64.65.255510
34141.64.66.0/23141.64.66.1 to 141.64.67.254141.64.67.255510
35141.64.68.0/23141.64.68.1 to 141.64.69.254141.64.69.255510
36141.64.70.0/23141.64.70.1 to 141.64.71.254141.64.71.255510
37141.64.72.0/23141.64.72.1 to 141.64.73.254141.64.73.255510
38141.64.74.0/23141.64.74.1 to 141.64.75.254141.64.75.255510
39141.64.76.0/23141.64.76.1 to 141.64.77.254141.64.77.255510
40141.64.78.0/23141.64.78.1 to 141.64.79.254141.64.79.255510
41141.64.80.0/23141.64.80.1 to 141.64.81.254141.64.81.255510
42141.64.82.0/23141.64.82.1 to 141.64.83.254141.64.83.255510
43141.64.84.0/23141.64.84.1 to 141.64.85.254141.64.85.255510
44141.64.86.0/23141.64.86.1 to 141.64.87.254141.64.87.255510
45141.64.88.0/23141.64.88.1 to 141.64.89.254141.64.89.255510
46141.64.90.0/23141.64.90.1 to 141.64.91.254141.64.91.255510
47141.64.92.0/23141.64.92.1 to 141.64.93.254141.64.93.255510
48141.64.94.0/23141.64.94.1 to 141.64.95.254141.64.95.255510
49141.64.96.0/23141.64.96.1 to 141.64.97.254141.64.97.255510
50141.64.98.0/23141.64.98.1 to 141.64.99.254141.64.99.255510
51141.64.100.0/23141.64.100.1 to 141.64.101.254141.64.101.255510
52141.64.102.0/23141.64.102.1 to 141.64.103.254141.64.103.255510
53141.64.104.0/23141.64.104.1 to 141.64.105.254141.64.105.255510
54141.64.106.0/23141.64.106.1 to 141.64.107.254141.64.107.255510
55141.64.108.0/23141.64.108.1 to 141.64.109.254141.64.109.255510
56141.64.110.0/23141.64.110.1 to 141.64.111.254141.64.111.255510
57141.64.112.0/23141.64.112.1 to 141.64.113.254141.64.113.255510
58141.64.114.0/23141.64.114.1 to 141.64.115.254141.64.115.255510
59141.64.116.0/23141.64.116.1 to 141.64.117.254141.64.117.255510
60141.64.118.0/23141.64.118.1 to 141.64.119.254141.64.119.255510
61141.64.120.0/23141.64.120.1 to 141.64.121.254141.64.121.255510
62141.64.122.0/23141.64.122.1 to 141.64.123.254141.64.123.255510
63141.64.124.0/23141.64.124.1 to 141.64.125.254141.64.125.255510
64141.64.126.0/23141.64.126.1 to 141.64.127.254141.64.127.255510
65141.64.128.0/23141.64.128.1 to 141.64.129.254141.64.129.255510
66141.64.130.0/23141.64.130.1 to 141.64.131.254141.64.131.255510
67141.64.132.0/23141.64.132.1 to 141.64.133.254141.64.133.255510
68141.64.134.0/23141.64.134.1 to 141.64.135.254141.64.135.255510
69141.64.136.0/23141.64.136.1 to 141.64.137.254141.64.137.255510
70141.64.138.0/23141.64.138.1 to 141.64.139.254141.64.139.255510
71141.64.140.0/23141.64.140.1 to 141.64.141.254141.64.141.255510
72141.64.142.0/23141.64.142.1 to 141.64.143.254141.64.143.255510
73141.64.144.0/23141.64.144.1 to 141.64.145.254141.64.145.255510
74141.64.146.0/23141.64.146.1 to 141.64.147.254141.64.147.255510
75141.64.148.0/23141.64.148.1 to 141.64.149.254141.64.149.255510
76141.64.150.0/23141.64.150.1 to 141.64.151.254141.64.151.255510
77141.64.152.0/23141.64.152.1 to 141.64.153.254141.64.153.255510
78141.64.154.0/23141.64.154.1 to 141.64.155.254141.64.155.255510
79141.64.156.0/23141.64.156.1 to 141.64.157.254141.64.157.255510
80141.64.158.0/23141.64.158.1 to 141.64.159.254141.64.159.255510
81141.64.160.0/23141.64.160.1 to 141.64.161.254141.64.161.255510
82141.64.162.0/23141.64.162.1 to 141.64.163.254141.64.163.255510
83141.64.164.0/23141.64.164.1 to 141.64.165.254141.64.165.255510
84141.64.166.0/23141.64.166.1 to 141.64.167.254141.64.167.255510
85141.64.168.0/23141.64.168.1 to 141.64.169.254141.64.169.255510
86141.64.170.0/23141.64.170.1 to 141.64.171.254141.64.171.255510
87141.64.172.0/23141.64.172.1 to 141.64.173.254141.64.173.255510
88141.64.174.0/23141.64.174.1 to 141.64.175.254141.64.175.255510
89141.64.176.0/23141.64.176.1 to 141.64.177.254141.64.177.255510
90141.64.178.0/23141.64.178.1 to 141.64.179.254141.64.179.255510
91141.64.180.0/23141.64.180.1 to 141.64.181.254141.64.181.255510
92141.64.182.0/23141.64.182.1 to 141.64.183.254141.64.183.255510
93141.64.184.0/23141.64.184.1 to 141.64.185.254141.64.185.255510
94141.64.186.0/23141.64.186.1 to 141.64.187.254141.64.187.255510
95141.64.188.0/23141.64.188.1 to 141.64.189.254141.64.189.255510
96141.64.190.0/23141.64.190.1 to 141.64.191.254141.64.191.255510
97141.64.192.0/23141.64.192.1 to 141.64.193.254141.64.193.255510
98141.64.194.0/23141.64.194.1 to 141.64.195.254141.64.195.255510
99141.64.196.0/23141.64.196.1 to 141.64.197.254141.64.197.255510
100141.64.198.0/23141.64.198.1 to 141.64.199.254141.64.199.255510
101141.64.200.0/23141.64.200.1 to 141.64.201.254141.64.201.255510
102141.64.202.0/23141.64.202.1 to 141.64.203.254141.64.203.255510
103141.64.204.0/23141.64.204.1 to 141.64.205.254141.64.205.255510
104141.64.206.0/23141.64.206.1 to 141.64.207.254141.64.207.255510
105141.64.208.0/23141.64.208.1 to 141.64.209.254141.64.209.255510
106141.64.210.0/23141.64.210.1 to 141.64.211.254141.64.211.255510
107141.64.212.0/23141.64.212.1 to 141.64.213.254141.64.213.255510
108141.64.214.0/23141.64.214.1 to 141.64.215.254141.64.215.255510
109141.64.216.0/23141.64.216.1 to 141.64.217.254141.64.217.255510
110141.64.218.0/23141.64.218.1 to 141.64.219.254141.64.219.255510
111141.64.220.0/23141.64.220.1 to 141.64.221.254141.64.221.255510
112141.64.222.0/23141.64.222.1 to 141.64.223.254141.64.223.255510
113141.64.224.0/23141.64.224.1 to 141.64.225.254141.64.225.255510
114141.64.226.0/23141.64.226.1 to 141.64.227.254141.64.227.255510
115141.64.228.0/23141.64.228.1 to 141.64.229.254141.64.229.255510
116141.64.230.0/23141.64.230.1 to 141.64.231.254141.64.231.255510
117141.64.232.0/23141.64.232.1 to 141.64.233.254141.64.233.255510
118141.64.234.0/23141.64.234.1 to 141.64.235.254141.64.235.255510
119141.64.236.0/23141.64.236.1 to 141.64.237.254141.64.237.255510
120141.64.238.0/23141.64.238.1 to 141.64.239.254141.64.239.255510
121141.64.240.0/23141.64.240.1 to 141.64.241.254141.64.241.255510
122141.64.242.0/23141.64.242.1 to 141.64.243.254141.64.243.255510
123141.64.244.0/23141.64.244.1 to 141.64.245.254141.64.245.255510
124141.64.246.0/23141.64.246.1 to 141.64.247.254141.64.247.255510
125141.64.248.0/23141.64.248.1 to 141.64.249.254141.64.249.255510
126141.64.250.0/23141.64.250.1 to 141.64.251.254141.64.251.255510
127141.64.252.0/23141.64.252.1 to 141.64.253.254141.64.253.255510
128141.64.254.0/23141.64.254.1 to 141.64.255.254141.64.255.255510
129141.65.0.0/23141.65.0.1 to 141.65.1.254141.65.1.255510
130141.65.2.0/23141.65.2.1 to 141.65.3.254141.65.3.255510
131141.65.4.0/23141.65.4.1 to 141.65.5.254141.65.5.255510
132141.65.6.0/23141.65.6.1 to 141.65.7.254141.65.7.255510
133141.65.8.0/23141.65.8.1 to 141.65.9.254141.65.9.255510
134141.65.10.0/23141.65.10.1 to 141.65.11.254141.65.11.255510
135141.65.12.0/23141.65.12.1 to 141.65.13.254141.65.13.255510
136141.65.14.0/23141.65.14.1 to 141.65.15.254141.65.15.255510
137141.65.16.0/23141.65.16.1 to 141.65.17.254141.65.17.255510
138141.65.18.0/23141.65.18.1 to 141.65.19.254141.65.19.255510
139141.65.20.0/23141.65.20.1 to 141.65.21.254141.65.21.255510
140141.65.22.0/23141.65.22.1 to 141.65.23.254141.65.23.255510
141141.65.24.0/23141.65.24.1 to 141.65.25.254141.65.25.255510
142141.65.26.0/23141.65.26.1 to 141.65.27.254141.65.27.255510
143141.65.28.0/23141.65.28.1 to 141.65.29.254141.65.29.255510
144141.65.30.0/23141.65.30.1 to 141.65.31.254141.65.31.255510
145141.65.32.0/23141.65.32.1 to 141.65.33.254141.65.33.255510
146141.65.34.0/23141.65.34.1 to 141.65.35.254141.65.35.255510
147141.65.36.0/23141.65.36.1 to 141.65.37.254141.65.37.255510
148141.65.38.0/23141.65.38.1 to 141.65.39.254141.65.39.255510
149141.65.40.0/23141.65.40.1 to 141.65.41.254141.65.41.255510
150141.65.42.0/23141.65.42.1 to 141.65.43.254141.65.43.255510
151141.65.44.0/23141.65.44.1 to 141.65.45.254141.65.45.255510
152141.65.46.0/23141.65.46.1 to 141.65.47.254141.65.47.255510
153141.65.48.0/23141.65.48.1 to 141.65.49.254141.65.49.255510
154141.65.50.0/23141.65.50.1 to 141.65.51.254141.65.51.255510
155141.65.52.0/23141.65.52.1 to 141.65.53.254141.65.53.255510
156141.65.54.0/23141.65.54.1 to 141.65.55.254141.65.55.255510
157141.65.56.0/23141.65.56.1 to 141.65.57.254141.65.57.255510
158141.65.58.0/23141.65.58.1 to 141.65.59.254141.65.59.255510
159141.65.60.0/23141.65.60.1 to 141.65.61.254141.65.61.255510
160141.65.62.0/23141.65.62.1 to 141.65.63.254141.65.63.255510
161141.65.64.0/23141.65.64.1 to 141.65.65.254141.65.65.255510
162141.65.66.0/23141.65.66.1 to 141.65.67.254141.65.67.255510
163141.65.68.0/23141.65.68.1 to 141.65.69.254141.65.69.255510
164141.65.70.0/23141.65.70.1 to 141.65.71.254141.65.71.255510
165141.65.72.0/23141.65.72.1 to 141.65.73.254141.65.73.255510
166141.65.74.0/23141.65.74.1 to 141.65.75.254141.65.75.255510
167141.65.76.0/23141.65.76.1 to 141.65.77.254141.65.77.255510
168141.65.78.0/23141.65.78.1 to 141.65.79.254141.65.79.255510
169141.65.80.0/23141.65.80.1 to 141.65.81.254141.65.81.255510
170141.65.82.0/23141.65.82.1 to 141.65.83.254141.65.83.255510
171141.65.84.0/23141.65.84.1 to 141.65.85.254141.65.85.255510
172141.65.86.0/23141.65.86.1 to 141.65.87.254141.65.87.255510
173141.65.88.0/23141.65.88.1 to 141.65.89.254141.65.89.255510
174141.65.90.0/23141.65.90.1 to 141.65.91.254141.65.91.255510
175141.65.92.0/23141.65.92.1 to 141.65.93.254141.65.93.255510
176141.65.94.0/23141.65.94.1 to 141.65.95.254141.65.95.255510
177141.65.96.0/23141.65.96.1 to 141.65.97.254141.65.97.255510
178141.65.98.0/23141.65.98.1 to 141.65.99.254141.65.99.255510
179141.65.100.0/23141.65.100.1 to 141.65.101.254141.65.101.255510
180141.65.102.0/23141.65.102.1 to 141.65.103.254141.65.103.255510
181141.65.104.0/23141.65.104.1 to 141.65.105.254141.65.105.255510
182141.65.106.0/23141.65.106.1 to 141.65.107.254141.65.107.255510
183141.65.108.0/23141.65.108.1 to 141.65.109.254141.65.109.255510
184141.65.110.0/23141.65.110.1 to 141.65.111.254141.65.111.255510
185141.65.112.0/23141.65.112.1 to 141.65.113.254141.65.113.255510
186141.65.114.0/23141.65.114.1 to 141.65.115.254141.65.115.255510
187141.65.116.0/23141.65.116.1 to 141.65.117.254141.65.117.255510
188141.65.118.0/23141.65.118.1 to 141.65.119.254141.65.119.255510
189141.65.120.0/23141.65.120.1 to 141.65.121.254141.65.121.255510
190141.65.122.0/23141.65.122.1 to 141.65.123.254141.65.123.255510
191141.65.124.0/23141.65.124.1 to 141.65.125.254141.65.125.255510
192141.65.126.0/23141.65.126.1 to 141.65.127.254141.65.127.255510
193141.65.128.0/23141.65.128.1 to 141.65.129.254141.65.129.255510
194141.65.130.0/23141.65.130.1 to 141.65.131.254141.65.131.255510
195141.65.132.0/23141.65.132.1 to 141.65.133.254141.65.133.255510
196141.65.134.0/23141.65.134.1 to 141.65.135.254141.65.135.255510
197141.65.136.0/23141.65.136.1 to 141.65.137.254141.65.137.255510
198141.65.138.0/23141.65.138.1 to 141.65.139.254141.65.139.255510
199141.65.140.0/23141.65.140.1 to 141.65.141.254141.65.141.255510
200141.65.142.0/23141.65.142.1 to 141.65.143.254141.65.143.255510
201141.65.144.0/23141.65.144.1 to 141.65.145.254141.65.145.255510
202141.65.146.0/23141.65.146.1 to 141.65.147.254141.65.147.255510
203141.65.148.0/23141.65.148.1 to 141.65.149.254141.65.149.255510
204141.65.150.0/23141.65.150.1 to 141.65.151.254141.65.151.255510
205141.65.152.0/23141.65.152.1 to 141.65.153.254141.65.153.255510
206141.65.154.0/23141.65.154.1 to 141.65.155.254141.65.155.255510
207141.65.156.0/23141.65.156.1 to 141.65.157.254141.65.157.255510
208141.65.158.0/23141.65.158.1 to 141.65.159.254141.65.159.255510
209141.65.160.0/23141.65.160.1 to 141.65.161.254141.65.161.255510
210141.65.162.0/23141.65.162.1 to 141.65.163.254141.65.163.255510
211141.65.164.0/23141.65.164.1 to 141.65.165.254141.65.165.255510
212141.65.166.0/23141.65.166.1 to 141.65.167.254141.65.167.255510
213141.65.168.0/23141.65.168.1 to 141.65.169.254141.65.169.255510
214141.65.170.0/23141.65.170.1 to 141.65.171.254141.65.171.255510
215141.65.172.0/23141.65.172.1 to 141.65.173.254141.65.173.255510
216141.65.174.0/23141.65.174.1 to 141.65.175.254141.65.175.255510
217141.65.176.0/23141.65.176.1 to 141.65.177.254141.65.177.255510
218141.65.178.0/23141.65.178.1 to 141.65.179.254141.65.179.255510
219141.65.180.0/23141.65.180.1 to 141.65.181.254141.65.181.255510
220141.65.182.0/23141.65.182.1 to 141.65.183.254141.65.183.255510
221141.65.184.0/23141.65.184.1 to 141.65.185.254141.65.185.255510
222141.65.186.0/23141.65.186.1 to 141.65.187.254141.65.187.255510
223141.65.188.0/23141.65.188.1 to 141.65.189.254141.65.189.255510
224141.65.190.0/23141.65.190.1 to 141.65.191.254141.65.191.255510
225141.65.192.0/23141.65.192.1 to 141.65.193.254141.65.193.255510
226141.65.194.0/23141.65.194.1 to 141.65.195.254141.65.195.255510
227141.65.196.0/23141.65.196.1 to 141.65.197.254141.65.197.255510
228141.65.198.0/23141.65.198.1 to 141.65.199.254141.65.199.255510
229141.65.200.0/23141.65.200.1 to 141.65.201.254141.65.201.255510
230141.65.202.0/23141.65.202.1 to 141.65.203.254141.65.203.255510
231141.65.204.0/23141.65.204.1 to 141.65.205.254141.65.205.255510
232141.65.206.0/23141.65.206.1 to 141.65.207.254141.65.207.255510
233141.65.208.0/23141.65.208.1 to 141.65.209.254141.65.209.255510
234141.65.210.0/23141.65.210.1 to 141.65.211.254141.65.211.255510
235141.65.212.0/23141.65.212.1 to 141.65.213.254141.65.213.255510
236141.65.214.0/23141.65.214.1 to 141.65.215.254141.65.215.255510
237141.65.216.0/23141.65.216.1 to 141.65.217.254141.65.217.255510
238141.65.218.0/23141.65.218.1 to 141.65.219.254141.65.219.255510
239141.65.220.0/23141.65.220.1 to 141.65.221.254141.65.221.255510
240141.65.222.0/23141.65.222.1 to 141.65.223.254141.65.223.255510
241141.65.224.0/23141.65.224.1 to 141.65.225.254141.65.225.255510
242141.65.226.0/23141.65.226.1 to 141.65.227.254141.65.227.255510
243141.65.228.0/23141.65.228.1 to 141.65.229.254141.65.229.255510
244141.65.230.0/23141.65.230.1 to 141.65.231.254141.65.231.255510
245141.65.232.0/23141.65.232.1 to 141.65.233.254141.65.233.255510
246141.65.234.0/23141.65.234.1 to 141.65.235.254141.65.235.255510
247141.65.236.0/23141.65.236.1 to 141.65.237.254141.65.237.255510
248141.65.238.0/23141.65.238.1 to 141.65.239.254141.65.239.255510
249141.65.240.0/23141.65.240.1 to 141.65.241.254141.65.241.255510
250141.65.242.0/23141.65.242.1 to 141.65.243.254141.65.243.255510
251141.65.244.0/23141.65.244.1 to 141.65.245.254141.65.245.255510
252141.65.246.0/23141.65.246.1 to 141.65.247.254141.65.247.255510
253141.65.248.0/23141.65.248.1 to 141.65.249.254141.65.249.255510
254141.65.250.0/23141.65.250.1 to 141.65.251.254141.65.251.255510
255141.65.252.0/23141.65.252.1 to 141.65.253.254141.65.253.255510
256141.65.254.0/23141.65.254.1 to 141.65.255.254141.65.255.255510

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.