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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.

Network140.0.0.0/6
Usable hosts67,108,862
Subnet mask252.0.0.0
Addresses67,108,864
Network address
140.0.0.0
Broadcast address
143.255.255.255
First usable
140.0.0.1
Last usable
143.255.255.254
Usable hosts
67,108,862 (67,108,864 less the network and broadcast addresses)
Subnet mask
252.0.0.0
Wildcard mask
3.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/6
Type
Public public
Old class
B (default /16)
As numbers
Hex 8C000000 · Integer 2348810240 to 2415919103
Reverse DNS zones
140.in-addr.arpa
141.in-addr.arpa
142.in-addr.arpa
143.in-addr.arpa
/6 is not on a 8-bit boundary, so it takes 4 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10001100.00000000.00000000.00000000140.0.0.0
Subnet mask11111100.00000000.00000000.00000000252.0.0.0
Network10001100.00000000.00000000.00000000140.0.0.0
Broadcast10001111.11111111.11111111.11111111143.255.255.255
Split into smaller subnets/15
/7 (2)/8 (4)/9 (8)/10 (16)/11 (32)/12 (64)/13 (128)/14 (256)/15 (512)/16 (1,024)/17 (2,048)/18 (4,096)

140.0.0.0/6 makes 512 subnets of /15; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1140.0.0.0/15140.0.0.1 to 140.1.255.254140.1.255.255131,070
2140.2.0.0/15140.2.0.1 to 140.3.255.254140.3.255.255131,070
3140.4.0.0/15140.4.0.1 to 140.5.255.254140.5.255.255131,070
4140.6.0.0/15140.6.0.1 to 140.7.255.254140.7.255.255131,070
5140.8.0.0/15140.8.0.1 to 140.9.255.254140.9.255.255131,070
6140.10.0.0/15140.10.0.1 to 140.11.255.254140.11.255.255131,070
7140.12.0.0/15140.12.0.1 to 140.13.255.254140.13.255.255131,070
8140.14.0.0/15140.14.0.1 to 140.15.255.254140.15.255.255131,070
9140.16.0.0/15140.16.0.1 to 140.17.255.254140.17.255.255131,070
10140.18.0.0/15140.18.0.1 to 140.19.255.254140.19.255.255131,070
11140.20.0.0/15140.20.0.1 to 140.21.255.254140.21.255.255131,070
12140.22.0.0/15140.22.0.1 to 140.23.255.254140.23.255.255131,070
13140.24.0.0/15140.24.0.1 to 140.25.255.254140.25.255.255131,070
14140.26.0.0/15140.26.0.1 to 140.27.255.254140.27.255.255131,070
15140.28.0.0/15140.28.0.1 to 140.29.255.254140.29.255.255131,070
16140.30.0.0/15140.30.0.1 to 140.31.255.254140.31.255.255131,070
17140.32.0.0/15140.32.0.1 to 140.33.255.254140.33.255.255131,070
18140.34.0.0/15140.34.0.1 to 140.35.255.254140.35.255.255131,070
19140.36.0.0/15140.36.0.1 to 140.37.255.254140.37.255.255131,070
20140.38.0.0/15140.38.0.1 to 140.39.255.254140.39.255.255131,070
21140.40.0.0/15140.40.0.1 to 140.41.255.254140.41.255.255131,070
22140.42.0.0/15140.42.0.1 to 140.43.255.254140.43.255.255131,070
23140.44.0.0/15140.44.0.1 to 140.45.255.254140.45.255.255131,070
24140.46.0.0/15140.46.0.1 to 140.47.255.254140.47.255.255131,070
25140.48.0.0/15140.48.0.1 to 140.49.255.254140.49.255.255131,070
26140.50.0.0/15140.50.0.1 to 140.51.255.254140.51.255.255131,070
27140.52.0.0/15140.52.0.1 to 140.53.255.254140.53.255.255131,070
28140.54.0.0/15140.54.0.1 to 140.55.255.254140.55.255.255131,070
29140.56.0.0/15140.56.0.1 to 140.57.255.254140.57.255.255131,070
30140.58.0.0/15140.58.0.1 to 140.59.255.254140.59.255.255131,070
31140.60.0.0/15140.60.0.1 to 140.61.255.254140.61.255.255131,070
32140.62.0.0/15140.62.0.1 to 140.63.255.254140.63.255.255131,070
33140.64.0.0/15140.64.0.1 to 140.65.255.254140.65.255.255131,070
34140.66.0.0/15140.66.0.1 to 140.67.255.254140.67.255.255131,070
35140.68.0.0/15140.68.0.1 to 140.69.255.254140.69.255.255131,070
36140.70.0.0/15140.70.0.1 to 140.71.255.254140.71.255.255131,070
37140.72.0.0/15140.72.0.1 to 140.73.255.254140.73.255.255131,070
38140.74.0.0/15140.74.0.1 to 140.75.255.254140.75.255.255131,070
39140.76.0.0/15140.76.0.1 to 140.77.255.254140.77.255.255131,070
40140.78.0.0/15140.78.0.1 to 140.79.255.254140.79.255.255131,070
41140.80.0.0/15140.80.0.1 to 140.81.255.254140.81.255.255131,070
42140.82.0.0/15140.82.0.1 to 140.83.255.254140.83.255.255131,070
43140.84.0.0/15140.84.0.1 to 140.85.255.254140.85.255.255131,070
44140.86.0.0/15140.86.0.1 to 140.87.255.254140.87.255.255131,070
45140.88.0.0/15140.88.0.1 to 140.89.255.254140.89.255.255131,070
46140.90.0.0/15140.90.0.1 to 140.91.255.254140.91.255.255131,070
47140.92.0.0/15140.92.0.1 to 140.93.255.254140.93.255.255131,070
48140.94.0.0/15140.94.0.1 to 140.95.255.254140.95.255.255131,070
49140.96.0.0/15140.96.0.1 to 140.97.255.254140.97.255.255131,070
50140.98.0.0/15140.98.0.1 to 140.99.255.254140.99.255.255131,070
51140.100.0.0/15140.100.0.1 to 140.101.255.254140.101.255.255131,070
52140.102.0.0/15140.102.0.1 to 140.103.255.254140.103.255.255131,070
53140.104.0.0/15140.104.0.1 to 140.105.255.254140.105.255.255131,070
54140.106.0.0/15140.106.0.1 to 140.107.255.254140.107.255.255131,070
55140.108.0.0/15140.108.0.1 to 140.109.255.254140.109.255.255131,070
56140.110.0.0/15140.110.0.1 to 140.111.255.254140.111.255.255131,070
57140.112.0.0/15140.112.0.1 to 140.113.255.254140.113.255.255131,070
58140.114.0.0/15140.114.0.1 to 140.115.255.254140.115.255.255131,070
59140.116.0.0/15140.116.0.1 to 140.117.255.254140.117.255.255131,070
60140.118.0.0/15140.118.0.1 to 140.119.255.254140.119.255.255131,070
61140.120.0.0/15140.120.0.1 to 140.121.255.254140.121.255.255131,070
62140.122.0.0/15140.122.0.1 to 140.123.255.254140.123.255.255131,070
63140.124.0.0/15140.124.0.1 to 140.125.255.254140.125.255.255131,070
64140.126.0.0/15140.126.0.1 to 140.127.255.254140.127.255.255131,070
65140.128.0.0/15140.128.0.1 to 140.129.255.254140.129.255.255131,070
66140.130.0.0/15140.130.0.1 to 140.131.255.254140.131.255.255131,070
67140.132.0.0/15140.132.0.1 to 140.133.255.254140.133.255.255131,070
68140.134.0.0/15140.134.0.1 to 140.135.255.254140.135.255.255131,070
69140.136.0.0/15140.136.0.1 to 140.137.255.254140.137.255.255131,070
70140.138.0.0/15140.138.0.1 to 140.139.255.254140.139.255.255131,070
71140.140.0.0/15140.140.0.1 to 140.141.255.254140.141.255.255131,070
72140.142.0.0/15140.142.0.1 to 140.143.255.254140.143.255.255131,070
73140.144.0.0/15140.144.0.1 to 140.145.255.254140.145.255.255131,070
74140.146.0.0/15140.146.0.1 to 140.147.255.254140.147.255.255131,070
75140.148.0.0/15140.148.0.1 to 140.149.255.254140.149.255.255131,070
76140.150.0.0/15140.150.0.1 to 140.151.255.254140.151.255.255131,070
77140.152.0.0/15140.152.0.1 to 140.153.255.254140.153.255.255131,070
78140.154.0.0/15140.154.0.1 to 140.155.255.254140.155.255.255131,070
79140.156.0.0/15140.156.0.1 to 140.157.255.254140.157.255.255131,070
80140.158.0.0/15140.158.0.1 to 140.159.255.254140.159.255.255131,070
81140.160.0.0/15140.160.0.1 to 140.161.255.254140.161.255.255131,070
82140.162.0.0/15140.162.0.1 to 140.163.255.254140.163.255.255131,070
83140.164.0.0/15140.164.0.1 to 140.165.255.254140.165.255.255131,070
84140.166.0.0/15140.166.0.1 to 140.167.255.254140.167.255.255131,070
85140.168.0.0/15140.168.0.1 to 140.169.255.254140.169.255.255131,070
86140.170.0.0/15140.170.0.1 to 140.171.255.254140.171.255.255131,070
87140.172.0.0/15140.172.0.1 to 140.173.255.254140.173.255.255131,070
88140.174.0.0/15140.174.0.1 to 140.175.255.254140.175.255.255131,070
89140.176.0.0/15140.176.0.1 to 140.177.255.254140.177.255.255131,070
90140.178.0.0/15140.178.0.1 to 140.179.255.254140.179.255.255131,070
91140.180.0.0/15140.180.0.1 to 140.181.255.254140.181.255.255131,070
92140.182.0.0/15140.182.0.1 to 140.183.255.254140.183.255.255131,070
93140.184.0.0/15140.184.0.1 to 140.185.255.254140.185.255.255131,070
94140.186.0.0/15140.186.0.1 to 140.187.255.254140.187.255.255131,070
95140.188.0.0/15140.188.0.1 to 140.189.255.254140.189.255.255131,070
96140.190.0.0/15140.190.0.1 to 140.191.255.254140.191.255.255131,070
97140.192.0.0/15140.192.0.1 to 140.193.255.254140.193.255.255131,070
98140.194.0.0/15140.194.0.1 to 140.195.255.254140.195.255.255131,070
99140.196.0.0/15140.196.0.1 to 140.197.255.254140.197.255.255131,070
100140.198.0.0/15140.198.0.1 to 140.199.255.254140.199.255.255131,070
101140.200.0.0/15140.200.0.1 to 140.201.255.254140.201.255.255131,070
102140.202.0.0/15140.202.0.1 to 140.203.255.254140.203.255.255131,070
103140.204.0.0/15140.204.0.1 to 140.205.255.254140.205.255.255131,070
104140.206.0.0/15140.206.0.1 to 140.207.255.254140.207.255.255131,070
105140.208.0.0/15140.208.0.1 to 140.209.255.254140.209.255.255131,070
106140.210.0.0/15140.210.0.1 to 140.211.255.254140.211.255.255131,070
107140.212.0.0/15140.212.0.1 to 140.213.255.254140.213.255.255131,070
108140.214.0.0/15140.214.0.1 to 140.215.255.254140.215.255.255131,070
109140.216.0.0/15140.216.0.1 to 140.217.255.254140.217.255.255131,070
110140.218.0.0/15140.218.0.1 to 140.219.255.254140.219.255.255131,070
111140.220.0.0/15140.220.0.1 to 140.221.255.254140.221.255.255131,070
112140.222.0.0/15140.222.0.1 to 140.223.255.254140.223.255.255131,070
113140.224.0.0/15140.224.0.1 to 140.225.255.254140.225.255.255131,070
114140.226.0.0/15140.226.0.1 to 140.227.255.254140.227.255.255131,070
115140.228.0.0/15140.228.0.1 to 140.229.255.254140.229.255.255131,070
116140.230.0.0/15140.230.0.1 to 140.231.255.254140.231.255.255131,070
117140.232.0.0/15140.232.0.1 to 140.233.255.254140.233.255.255131,070
118140.234.0.0/15140.234.0.1 to 140.235.255.254140.235.255.255131,070
119140.236.0.0/15140.236.0.1 to 140.237.255.254140.237.255.255131,070
120140.238.0.0/15140.238.0.1 to 140.239.255.254140.239.255.255131,070
121140.240.0.0/15140.240.0.1 to 140.241.255.254140.241.255.255131,070
122140.242.0.0/15140.242.0.1 to 140.243.255.254140.243.255.255131,070
123140.244.0.0/15140.244.0.1 to 140.245.255.254140.245.255.255131,070
124140.246.0.0/15140.246.0.1 to 140.247.255.254140.247.255.255131,070
125140.248.0.0/15140.248.0.1 to 140.249.255.254140.249.255.255131,070
126140.250.0.0/15140.250.0.1 to 140.251.255.254140.251.255.255131,070
127140.252.0.0/15140.252.0.1 to 140.253.255.254140.253.255.255131,070
128140.254.0.0/15140.254.0.1 to 140.255.255.254140.255.255.255131,070
129141.0.0.0/15141.0.0.1 to 141.1.255.254141.1.255.255131,070
130141.2.0.0/15141.2.0.1 to 141.3.255.254141.3.255.255131,070
131141.4.0.0/15141.4.0.1 to 141.5.255.254141.5.255.255131,070
132141.6.0.0/15141.6.0.1 to 141.7.255.254141.7.255.255131,070
133141.8.0.0/15141.8.0.1 to 141.9.255.254141.9.255.255131,070
134141.10.0.0/15141.10.0.1 to 141.11.255.254141.11.255.255131,070
135141.12.0.0/15141.12.0.1 to 141.13.255.254141.13.255.255131,070
136141.14.0.0/15141.14.0.1 to 141.15.255.254141.15.255.255131,070
137141.16.0.0/15141.16.0.1 to 141.17.255.254141.17.255.255131,070
138141.18.0.0/15141.18.0.1 to 141.19.255.254141.19.255.255131,070
139141.20.0.0/15141.20.0.1 to 141.21.255.254141.21.255.255131,070
140141.22.0.0/15141.22.0.1 to 141.23.255.254141.23.255.255131,070
141141.24.0.0/15141.24.0.1 to 141.25.255.254141.25.255.255131,070
142141.26.0.0/15141.26.0.1 to 141.27.255.254141.27.255.255131,070
143141.28.0.0/15141.28.0.1 to 141.29.255.254141.29.255.255131,070
144141.30.0.0/15141.30.0.1 to 141.31.255.254141.31.255.255131,070
145141.32.0.0/15141.32.0.1 to 141.33.255.254141.33.255.255131,070
146141.34.0.0/15141.34.0.1 to 141.35.255.254141.35.255.255131,070
147141.36.0.0/15141.36.0.1 to 141.37.255.254141.37.255.255131,070
148141.38.0.0/15141.38.0.1 to 141.39.255.254141.39.255.255131,070
149141.40.0.0/15141.40.0.1 to 141.41.255.254141.41.255.255131,070
150141.42.0.0/15141.42.0.1 to 141.43.255.254141.43.255.255131,070
151141.44.0.0/15141.44.0.1 to 141.45.255.254141.45.255.255131,070
152141.46.0.0/15141.46.0.1 to 141.47.255.254141.47.255.255131,070
153141.48.0.0/15141.48.0.1 to 141.49.255.254141.49.255.255131,070
154141.50.0.0/15141.50.0.1 to 141.51.255.254141.51.255.255131,070
155141.52.0.0/15141.52.0.1 to 141.53.255.254141.53.255.255131,070
156141.54.0.0/15141.54.0.1 to 141.55.255.254141.55.255.255131,070
157141.56.0.0/15141.56.0.1 to 141.57.255.254141.57.255.255131,070
158141.58.0.0/15141.58.0.1 to 141.59.255.254141.59.255.255131,070
159141.60.0.0/15141.60.0.1 to 141.61.255.254141.61.255.255131,070
160141.62.0.0/15141.62.0.1 to 141.63.255.254141.63.255.255131,070
161141.64.0.0/15141.64.0.1 to 141.65.255.254141.65.255.255131,070
162141.66.0.0/15141.66.0.1 to 141.67.255.254141.67.255.255131,070
163141.68.0.0/15141.68.0.1 to 141.69.255.254141.69.255.255131,070
164141.70.0.0/15141.70.0.1 to 141.71.255.254141.71.255.255131,070
165141.72.0.0/15141.72.0.1 to 141.73.255.254141.73.255.255131,070
166141.74.0.0/15141.74.0.1 to 141.75.255.254141.75.255.255131,070
167141.76.0.0/15141.76.0.1 to 141.77.255.254141.77.255.255131,070
168141.78.0.0/15141.78.0.1 to 141.79.255.254141.79.255.255131,070
169141.80.0.0/15141.80.0.1 to 141.81.255.254141.81.255.255131,070
170141.82.0.0/15141.82.0.1 to 141.83.255.254141.83.255.255131,070
171141.84.0.0/15141.84.0.1 to 141.85.255.254141.85.255.255131,070
172141.86.0.0/15141.86.0.1 to 141.87.255.254141.87.255.255131,070
173141.88.0.0/15141.88.0.1 to 141.89.255.254141.89.255.255131,070
174141.90.0.0/15141.90.0.1 to 141.91.255.254141.91.255.255131,070
175141.92.0.0/15141.92.0.1 to 141.93.255.254141.93.255.255131,070
176141.94.0.0/15141.94.0.1 to 141.95.255.254141.95.255.255131,070
177141.96.0.0/15141.96.0.1 to 141.97.255.254141.97.255.255131,070
178141.98.0.0/15141.98.0.1 to 141.99.255.254141.99.255.255131,070
179141.100.0.0/15141.100.0.1 to 141.101.255.254141.101.255.255131,070
180141.102.0.0/15141.102.0.1 to 141.103.255.254141.103.255.255131,070
181141.104.0.0/15141.104.0.1 to 141.105.255.254141.105.255.255131,070
182141.106.0.0/15141.106.0.1 to 141.107.255.254141.107.255.255131,070
183141.108.0.0/15141.108.0.1 to 141.109.255.254141.109.255.255131,070
184141.110.0.0/15141.110.0.1 to 141.111.255.254141.111.255.255131,070
185141.112.0.0/15141.112.0.1 to 141.113.255.254141.113.255.255131,070
186141.114.0.0/15141.114.0.1 to 141.115.255.254141.115.255.255131,070
187141.116.0.0/15141.116.0.1 to 141.117.255.254141.117.255.255131,070
188141.118.0.0/15141.118.0.1 to 141.119.255.254141.119.255.255131,070
189141.120.0.0/15141.120.0.1 to 141.121.255.254141.121.255.255131,070
190141.122.0.0/15141.122.0.1 to 141.123.255.254141.123.255.255131,070
191141.124.0.0/15141.124.0.1 to 141.125.255.254141.125.255.255131,070
192141.126.0.0/15141.126.0.1 to 141.127.255.254141.127.255.255131,070
193141.128.0.0/15141.128.0.1 to 141.129.255.254141.129.255.255131,070
194141.130.0.0/15141.130.0.1 to 141.131.255.254141.131.255.255131,070
195141.132.0.0/15141.132.0.1 to 141.133.255.254141.133.255.255131,070
196141.134.0.0/15141.134.0.1 to 141.135.255.254141.135.255.255131,070
197141.136.0.0/15141.136.0.1 to 141.137.255.254141.137.255.255131,070
198141.138.0.0/15141.138.0.1 to 141.139.255.254141.139.255.255131,070
199141.140.0.0/15141.140.0.1 to 141.141.255.254141.141.255.255131,070
200141.142.0.0/15141.142.0.1 to 141.143.255.254141.143.255.255131,070
201141.144.0.0/15141.144.0.1 to 141.145.255.254141.145.255.255131,070
202141.146.0.0/15141.146.0.1 to 141.147.255.254141.147.255.255131,070
203141.148.0.0/15141.148.0.1 to 141.149.255.254141.149.255.255131,070
204141.150.0.0/15141.150.0.1 to 141.151.255.254141.151.255.255131,070
205141.152.0.0/15141.152.0.1 to 141.153.255.254141.153.255.255131,070
206141.154.0.0/15141.154.0.1 to 141.155.255.254141.155.255.255131,070
207141.156.0.0/15141.156.0.1 to 141.157.255.254141.157.255.255131,070
208141.158.0.0/15141.158.0.1 to 141.159.255.254141.159.255.255131,070
209141.160.0.0/15141.160.0.1 to 141.161.255.254141.161.255.255131,070
210141.162.0.0/15141.162.0.1 to 141.163.255.254141.163.255.255131,070
211141.164.0.0/15141.164.0.1 to 141.165.255.254141.165.255.255131,070
212141.166.0.0/15141.166.0.1 to 141.167.255.254141.167.255.255131,070
213141.168.0.0/15141.168.0.1 to 141.169.255.254141.169.255.255131,070
214141.170.0.0/15141.170.0.1 to 141.171.255.254141.171.255.255131,070
215141.172.0.0/15141.172.0.1 to 141.173.255.254141.173.255.255131,070
216141.174.0.0/15141.174.0.1 to 141.175.255.254141.175.255.255131,070
217141.176.0.0/15141.176.0.1 to 141.177.255.254141.177.255.255131,070
218141.178.0.0/15141.178.0.1 to 141.179.255.254141.179.255.255131,070
219141.180.0.0/15141.180.0.1 to 141.181.255.254141.181.255.255131,070
220141.182.0.0/15141.182.0.1 to 141.183.255.254141.183.255.255131,070
221141.184.0.0/15141.184.0.1 to 141.185.255.254141.185.255.255131,070
222141.186.0.0/15141.186.0.1 to 141.187.255.254141.187.255.255131,070
223141.188.0.0/15141.188.0.1 to 141.189.255.254141.189.255.255131,070
224141.190.0.0/15141.190.0.1 to 141.191.255.254141.191.255.255131,070
225141.192.0.0/15141.192.0.1 to 141.193.255.254141.193.255.255131,070
226141.194.0.0/15141.194.0.1 to 141.195.255.254141.195.255.255131,070
227141.196.0.0/15141.196.0.1 to 141.197.255.254141.197.255.255131,070
228141.198.0.0/15141.198.0.1 to 141.199.255.254141.199.255.255131,070
229141.200.0.0/15141.200.0.1 to 141.201.255.254141.201.255.255131,070
230141.202.0.0/15141.202.0.1 to 141.203.255.254141.203.255.255131,070
231141.204.0.0/15141.204.0.1 to 141.205.255.254141.205.255.255131,070
232141.206.0.0/15141.206.0.1 to 141.207.255.254141.207.255.255131,070
233141.208.0.0/15141.208.0.1 to 141.209.255.254141.209.255.255131,070
234141.210.0.0/15141.210.0.1 to 141.211.255.254141.211.255.255131,070
235141.212.0.0/15141.212.0.1 to 141.213.255.254141.213.255.255131,070
236141.214.0.0/15141.214.0.1 to 141.215.255.254141.215.255.255131,070
237141.216.0.0/15141.216.0.1 to 141.217.255.254141.217.255.255131,070
238141.218.0.0/15141.218.0.1 to 141.219.255.254141.219.255.255131,070
239141.220.0.0/15141.220.0.1 to 141.221.255.254141.221.255.255131,070
240141.222.0.0/15141.222.0.1 to 141.223.255.254141.223.255.255131,070
241141.224.0.0/15141.224.0.1 to 141.225.255.254141.225.255.255131,070
242141.226.0.0/15141.226.0.1 to 141.227.255.254141.227.255.255131,070
243141.228.0.0/15141.228.0.1 to 141.229.255.254141.229.255.255131,070
244141.230.0.0/15141.230.0.1 to 141.231.255.254141.231.255.255131,070
245141.232.0.0/15141.232.0.1 to 141.233.255.254141.233.255.255131,070
246141.234.0.0/15141.234.0.1 to 141.235.255.254141.235.255.255131,070
247141.236.0.0/15141.236.0.1 to 141.237.255.254141.237.255.255131,070
248141.238.0.0/15141.238.0.1 to 141.239.255.254141.239.255.255131,070
249141.240.0.0/15141.240.0.1 to 141.241.255.254141.241.255.255131,070
250141.242.0.0/15141.242.0.1 to 141.243.255.254141.243.255.255131,070
251141.244.0.0/15141.244.0.1 to 141.245.255.254141.245.255.255131,070
252141.246.0.0/15141.246.0.1 to 141.247.255.254141.247.255.255131,070
253141.248.0.0/15141.248.0.1 to 141.249.255.254141.249.255.255131,070
254141.250.0.0/15141.250.0.1 to 141.251.255.254141.251.255.255131,070
255141.252.0.0/15141.252.0.1 to 141.253.255.254141.253.255.255131,070
256141.254.0.0/15141.254.0.1 to 141.255.255.254141.255.255.255131,070

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.