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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.

Network142.0.0.0/7
Usable hosts33,554,430
Subnet mask254.0.0.0
Addresses33,554,432
Network address
142.0.0.0
Broadcast address
143.255.255.255
First usable
142.0.0.1
Last usable
143.255.255.254
Usable hosts
33,554,430 (33,554,432 less the network and broadcast addresses)
Subnet mask
254.0.0.0
Wildcard mask
1.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/7
Type
Public public
Old class
B (default /16)
As numbers
Hex 8E000000 · Integer 2382364672 to 2415919103
Reverse DNS zones
142.in-addr.arpa
143.in-addr.arpa
/7 is not on a 8-bit boundary, so it takes 2 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10001110.00000000.00000000.00000000142.0.0.0
Subnet mask11111110.00000000.00000000.00000000254.0.0.0
Network10001110.00000000.00000000.00000000142.0.0.0
Broadcast10001111.11111111.11111111.11111111143.255.255.255
Split into smaller subnets/16
/8 (2)/9 (4)/10 (8)/11 (16)/12 (32)/13 (64)/14 (128)/15 (256)/16 (512)/17 (1,024)/18 (2,048)/19 (4,096)

142.0.0.0/7 makes 512 subnets of /16; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1142.0.0.0/16142.0.0.1 to 142.0.255.254142.0.255.25565,534
2142.1.0.0/16142.1.0.1 to 142.1.255.254142.1.255.25565,534
3142.2.0.0/16142.2.0.1 to 142.2.255.254142.2.255.25565,534
4142.3.0.0/16142.3.0.1 to 142.3.255.254142.3.255.25565,534
5142.4.0.0/16142.4.0.1 to 142.4.255.254142.4.255.25565,534
6142.5.0.0/16142.5.0.1 to 142.5.255.254142.5.255.25565,534
7142.6.0.0/16142.6.0.1 to 142.6.255.254142.6.255.25565,534
8142.7.0.0/16142.7.0.1 to 142.7.255.254142.7.255.25565,534
9142.8.0.0/16142.8.0.1 to 142.8.255.254142.8.255.25565,534
10142.9.0.0/16142.9.0.1 to 142.9.255.254142.9.255.25565,534
11142.10.0.0/16142.10.0.1 to 142.10.255.254142.10.255.25565,534
12142.11.0.0/16142.11.0.1 to 142.11.255.254142.11.255.25565,534
13142.12.0.0/16142.12.0.1 to 142.12.255.254142.12.255.25565,534
14142.13.0.0/16142.13.0.1 to 142.13.255.254142.13.255.25565,534
15142.14.0.0/16142.14.0.1 to 142.14.255.254142.14.255.25565,534
16142.15.0.0/16142.15.0.1 to 142.15.255.254142.15.255.25565,534
17142.16.0.0/16142.16.0.1 to 142.16.255.254142.16.255.25565,534
18142.17.0.0/16142.17.0.1 to 142.17.255.254142.17.255.25565,534
19142.18.0.0/16142.18.0.1 to 142.18.255.254142.18.255.25565,534
20142.19.0.0/16142.19.0.1 to 142.19.255.254142.19.255.25565,534
21142.20.0.0/16142.20.0.1 to 142.20.255.254142.20.255.25565,534
22142.21.0.0/16142.21.0.1 to 142.21.255.254142.21.255.25565,534
23142.22.0.0/16142.22.0.1 to 142.22.255.254142.22.255.25565,534
24142.23.0.0/16142.23.0.1 to 142.23.255.254142.23.255.25565,534
25142.24.0.0/16142.24.0.1 to 142.24.255.254142.24.255.25565,534
26142.25.0.0/16142.25.0.1 to 142.25.255.254142.25.255.25565,534
27142.26.0.0/16142.26.0.1 to 142.26.255.254142.26.255.25565,534
28142.27.0.0/16142.27.0.1 to 142.27.255.254142.27.255.25565,534
29142.28.0.0/16142.28.0.1 to 142.28.255.254142.28.255.25565,534
30142.29.0.0/16142.29.0.1 to 142.29.255.254142.29.255.25565,534
31142.30.0.0/16142.30.0.1 to 142.30.255.254142.30.255.25565,534
32142.31.0.0/16142.31.0.1 to 142.31.255.254142.31.255.25565,534
33142.32.0.0/16142.32.0.1 to 142.32.255.254142.32.255.25565,534
34142.33.0.0/16142.33.0.1 to 142.33.255.254142.33.255.25565,534
35142.34.0.0/16142.34.0.1 to 142.34.255.254142.34.255.25565,534
36142.35.0.0/16142.35.0.1 to 142.35.255.254142.35.255.25565,534
37142.36.0.0/16142.36.0.1 to 142.36.255.254142.36.255.25565,534
38142.37.0.0/16142.37.0.1 to 142.37.255.254142.37.255.25565,534
39142.38.0.0/16142.38.0.1 to 142.38.255.254142.38.255.25565,534
40142.39.0.0/16142.39.0.1 to 142.39.255.254142.39.255.25565,534
41142.40.0.0/16142.40.0.1 to 142.40.255.254142.40.255.25565,534
42142.41.0.0/16142.41.0.1 to 142.41.255.254142.41.255.25565,534
43142.42.0.0/16142.42.0.1 to 142.42.255.254142.42.255.25565,534
44142.43.0.0/16142.43.0.1 to 142.43.255.254142.43.255.25565,534
45142.44.0.0/16142.44.0.1 to 142.44.255.254142.44.255.25565,534
46142.45.0.0/16142.45.0.1 to 142.45.255.254142.45.255.25565,534
47142.46.0.0/16142.46.0.1 to 142.46.255.254142.46.255.25565,534
48142.47.0.0/16142.47.0.1 to 142.47.255.254142.47.255.25565,534
49142.48.0.0/16142.48.0.1 to 142.48.255.254142.48.255.25565,534
50142.49.0.0/16142.49.0.1 to 142.49.255.254142.49.255.25565,534
51142.50.0.0/16142.50.0.1 to 142.50.255.254142.50.255.25565,534
52142.51.0.0/16142.51.0.1 to 142.51.255.254142.51.255.25565,534
53142.52.0.0/16142.52.0.1 to 142.52.255.254142.52.255.25565,534
54142.53.0.0/16142.53.0.1 to 142.53.255.254142.53.255.25565,534
55142.54.0.0/16142.54.0.1 to 142.54.255.254142.54.255.25565,534
56142.55.0.0/16142.55.0.1 to 142.55.255.254142.55.255.25565,534
57142.56.0.0/16142.56.0.1 to 142.56.255.254142.56.255.25565,534
58142.57.0.0/16142.57.0.1 to 142.57.255.254142.57.255.25565,534
59142.58.0.0/16142.58.0.1 to 142.58.255.254142.58.255.25565,534
60142.59.0.0/16142.59.0.1 to 142.59.255.254142.59.255.25565,534
61142.60.0.0/16142.60.0.1 to 142.60.255.254142.60.255.25565,534
62142.61.0.0/16142.61.0.1 to 142.61.255.254142.61.255.25565,534
63142.62.0.0/16142.62.0.1 to 142.62.255.254142.62.255.25565,534
64142.63.0.0/16142.63.0.1 to 142.63.255.254142.63.255.25565,534
65142.64.0.0/16142.64.0.1 to 142.64.255.254142.64.255.25565,534
66142.65.0.0/16142.65.0.1 to 142.65.255.254142.65.255.25565,534
67142.66.0.0/16142.66.0.1 to 142.66.255.254142.66.255.25565,534
68142.67.0.0/16142.67.0.1 to 142.67.255.254142.67.255.25565,534
69142.68.0.0/16142.68.0.1 to 142.68.255.254142.68.255.25565,534
70142.69.0.0/16142.69.0.1 to 142.69.255.254142.69.255.25565,534
71142.70.0.0/16142.70.0.1 to 142.70.255.254142.70.255.25565,534
72142.71.0.0/16142.71.0.1 to 142.71.255.254142.71.255.25565,534
73142.72.0.0/16142.72.0.1 to 142.72.255.254142.72.255.25565,534
74142.73.0.0/16142.73.0.1 to 142.73.255.254142.73.255.25565,534
75142.74.0.0/16142.74.0.1 to 142.74.255.254142.74.255.25565,534
76142.75.0.0/16142.75.0.1 to 142.75.255.254142.75.255.25565,534
77142.76.0.0/16142.76.0.1 to 142.76.255.254142.76.255.25565,534
78142.77.0.0/16142.77.0.1 to 142.77.255.254142.77.255.25565,534
79142.78.0.0/16142.78.0.1 to 142.78.255.254142.78.255.25565,534
80142.79.0.0/16142.79.0.1 to 142.79.255.254142.79.255.25565,534
81142.80.0.0/16142.80.0.1 to 142.80.255.254142.80.255.25565,534
82142.81.0.0/16142.81.0.1 to 142.81.255.254142.81.255.25565,534
83142.82.0.0/16142.82.0.1 to 142.82.255.254142.82.255.25565,534
84142.83.0.0/16142.83.0.1 to 142.83.255.254142.83.255.25565,534
85142.84.0.0/16142.84.0.1 to 142.84.255.254142.84.255.25565,534
86142.85.0.0/16142.85.0.1 to 142.85.255.254142.85.255.25565,534
87142.86.0.0/16142.86.0.1 to 142.86.255.254142.86.255.25565,534
88142.87.0.0/16142.87.0.1 to 142.87.255.254142.87.255.25565,534
89142.88.0.0/16142.88.0.1 to 142.88.255.254142.88.255.25565,534
90142.89.0.0/16142.89.0.1 to 142.89.255.254142.89.255.25565,534
91142.90.0.0/16142.90.0.1 to 142.90.255.254142.90.255.25565,534
92142.91.0.0/16142.91.0.1 to 142.91.255.254142.91.255.25565,534
93142.92.0.0/16142.92.0.1 to 142.92.255.254142.92.255.25565,534
94142.93.0.0/16142.93.0.1 to 142.93.255.254142.93.255.25565,534
95142.94.0.0/16142.94.0.1 to 142.94.255.254142.94.255.25565,534
96142.95.0.0/16142.95.0.1 to 142.95.255.254142.95.255.25565,534
97142.96.0.0/16142.96.0.1 to 142.96.255.254142.96.255.25565,534
98142.97.0.0/16142.97.0.1 to 142.97.255.254142.97.255.25565,534
99142.98.0.0/16142.98.0.1 to 142.98.255.254142.98.255.25565,534
100142.99.0.0/16142.99.0.1 to 142.99.255.254142.99.255.25565,534
101142.100.0.0/16142.100.0.1 to 142.100.255.254142.100.255.25565,534
102142.101.0.0/16142.101.0.1 to 142.101.255.254142.101.255.25565,534
103142.102.0.0/16142.102.0.1 to 142.102.255.254142.102.255.25565,534
104142.103.0.0/16142.103.0.1 to 142.103.255.254142.103.255.25565,534
105142.104.0.0/16142.104.0.1 to 142.104.255.254142.104.255.25565,534
106142.105.0.0/16142.105.0.1 to 142.105.255.254142.105.255.25565,534
107142.106.0.0/16142.106.0.1 to 142.106.255.254142.106.255.25565,534
108142.107.0.0/16142.107.0.1 to 142.107.255.254142.107.255.25565,534
109142.108.0.0/16142.108.0.1 to 142.108.255.254142.108.255.25565,534
110142.109.0.0/16142.109.0.1 to 142.109.255.254142.109.255.25565,534
111142.110.0.0/16142.110.0.1 to 142.110.255.254142.110.255.25565,534
112142.111.0.0/16142.111.0.1 to 142.111.255.254142.111.255.25565,534
113142.112.0.0/16142.112.0.1 to 142.112.255.254142.112.255.25565,534
114142.113.0.0/16142.113.0.1 to 142.113.255.254142.113.255.25565,534
115142.114.0.0/16142.114.0.1 to 142.114.255.254142.114.255.25565,534
116142.115.0.0/16142.115.0.1 to 142.115.255.254142.115.255.25565,534
117142.116.0.0/16142.116.0.1 to 142.116.255.254142.116.255.25565,534
118142.117.0.0/16142.117.0.1 to 142.117.255.254142.117.255.25565,534
119142.118.0.0/16142.118.0.1 to 142.118.255.254142.118.255.25565,534
120142.119.0.0/16142.119.0.1 to 142.119.255.254142.119.255.25565,534
121142.120.0.0/16142.120.0.1 to 142.120.255.254142.120.255.25565,534
122142.121.0.0/16142.121.0.1 to 142.121.255.254142.121.255.25565,534
123142.122.0.0/16142.122.0.1 to 142.122.255.254142.122.255.25565,534
124142.123.0.0/16142.123.0.1 to 142.123.255.254142.123.255.25565,534
125142.124.0.0/16142.124.0.1 to 142.124.255.254142.124.255.25565,534
126142.125.0.0/16142.125.0.1 to 142.125.255.254142.125.255.25565,534
127142.126.0.0/16142.126.0.1 to 142.126.255.254142.126.255.25565,534
128142.127.0.0/16142.127.0.1 to 142.127.255.254142.127.255.25565,534
129142.128.0.0/16142.128.0.1 to 142.128.255.254142.128.255.25565,534
130142.129.0.0/16142.129.0.1 to 142.129.255.254142.129.255.25565,534
131142.130.0.0/16142.130.0.1 to 142.130.255.254142.130.255.25565,534
132142.131.0.0/16142.131.0.1 to 142.131.255.254142.131.255.25565,534
133142.132.0.0/16142.132.0.1 to 142.132.255.254142.132.255.25565,534
134142.133.0.0/16142.133.0.1 to 142.133.255.254142.133.255.25565,534
135142.134.0.0/16142.134.0.1 to 142.134.255.254142.134.255.25565,534
136142.135.0.0/16142.135.0.1 to 142.135.255.254142.135.255.25565,534
137142.136.0.0/16142.136.0.1 to 142.136.255.254142.136.255.25565,534
138142.137.0.0/16142.137.0.1 to 142.137.255.254142.137.255.25565,534
139142.138.0.0/16142.138.0.1 to 142.138.255.254142.138.255.25565,534
140142.139.0.0/16142.139.0.1 to 142.139.255.254142.139.255.25565,534
141142.140.0.0/16142.140.0.1 to 142.140.255.254142.140.255.25565,534
142142.141.0.0/16142.141.0.1 to 142.141.255.254142.141.255.25565,534
143142.142.0.0/16142.142.0.1 to 142.142.255.254142.142.255.25565,534
144142.143.0.0/16142.143.0.1 to 142.143.255.254142.143.255.25565,534
145142.144.0.0/16142.144.0.1 to 142.144.255.254142.144.255.25565,534
146142.145.0.0/16142.145.0.1 to 142.145.255.254142.145.255.25565,534
147142.146.0.0/16142.146.0.1 to 142.146.255.254142.146.255.25565,534
148142.147.0.0/16142.147.0.1 to 142.147.255.254142.147.255.25565,534
149142.148.0.0/16142.148.0.1 to 142.148.255.254142.148.255.25565,534
150142.149.0.0/16142.149.0.1 to 142.149.255.254142.149.255.25565,534
151142.150.0.0/16142.150.0.1 to 142.150.255.254142.150.255.25565,534
152142.151.0.0/16142.151.0.1 to 142.151.255.254142.151.255.25565,534
153142.152.0.0/16142.152.0.1 to 142.152.255.254142.152.255.25565,534
154142.153.0.0/16142.153.0.1 to 142.153.255.254142.153.255.25565,534
155142.154.0.0/16142.154.0.1 to 142.154.255.254142.154.255.25565,534
156142.155.0.0/16142.155.0.1 to 142.155.255.254142.155.255.25565,534
157142.156.0.0/16142.156.0.1 to 142.156.255.254142.156.255.25565,534
158142.157.0.0/16142.157.0.1 to 142.157.255.254142.157.255.25565,534
159142.158.0.0/16142.158.0.1 to 142.158.255.254142.158.255.25565,534
160142.159.0.0/16142.159.0.1 to 142.159.255.254142.159.255.25565,534
161142.160.0.0/16142.160.0.1 to 142.160.255.254142.160.255.25565,534
162142.161.0.0/16142.161.0.1 to 142.161.255.254142.161.255.25565,534
163142.162.0.0/16142.162.0.1 to 142.162.255.254142.162.255.25565,534
164142.163.0.0/16142.163.0.1 to 142.163.255.254142.163.255.25565,534
165142.164.0.0/16142.164.0.1 to 142.164.255.254142.164.255.25565,534
166142.165.0.0/16142.165.0.1 to 142.165.255.254142.165.255.25565,534
167142.166.0.0/16142.166.0.1 to 142.166.255.254142.166.255.25565,534
168142.167.0.0/16142.167.0.1 to 142.167.255.254142.167.255.25565,534
169142.168.0.0/16142.168.0.1 to 142.168.255.254142.168.255.25565,534
170142.169.0.0/16142.169.0.1 to 142.169.255.254142.169.255.25565,534
171142.170.0.0/16142.170.0.1 to 142.170.255.254142.170.255.25565,534
172142.171.0.0/16142.171.0.1 to 142.171.255.254142.171.255.25565,534
173142.172.0.0/16142.172.0.1 to 142.172.255.254142.172.255.25565,534
174142.173.0.0/16142.173.0.1 to 142.173.255.254142.173.255.25565,534
175142.174.0.0/16142.174.0.1 to 142.174.255.254142.174.255.25565,534
176142.175.0.0/16142.175.0.1 to 142.175.255.254142.175.255.25565,534
177142.176.0.0/16142.176.0.1 to 142.176.255.254142.176.255.25565,534
178142.177.0.0/16142.177.0.1 to 142.177.255.254142.177.255.25565,534
179142.178.0.0/16142.178.0.1 to 142.178.255.254142.178.255.25565,534
180142.179.0.0/16142.179.0.1 to 142.179.255.254142.179.255.25565,534
181142.180.0.0/16142.180.0.1 to 142.180.255.254142.180.255.25565,534
182142.181.0.0/16142.181.0.1 to 142.181.255.254142.181.255.25565,534
183142.182.0.0/16142.182.0.1 to 142.182.255.254142.182.255.25565,534
184142.183.0.0/16142.183.0.1 to 142.183.255.254142.183.255.25565,534
185142.184.0.0/16142.184.0.1 to 142.184.255.254142.184.255.25565,534
186142.185.0.0/16142.185.0.1 to 142.185.255.254142.185.255.25565,534
187142.186.0.0/16142.186.0.1 to 142.186.255.254142.186.255.25565,534
188142.187.0.0/16142.187.0.1 to 142.187.255.254142.187.255.25565,534
189142.188.0.0/16142.188.0.1 to 142.188.255.254142.188.255.25565,534
190142.189.0.0/16142.189.0.1 to 142.189.255.254142.189.255.25565,534
191142.190.0.0/16142.190.0.1 to 142.190.255.254142.190.255.25565,534
192142.191.0.0/16142.191.0.1 to 142.191.255.254142.191.255.25565,534
193142.192.0.0/16142.192.0.1 to 142.192.255.254142.192.255.25565,534
194142.193.0.0/16142.193.0.1 to 142.193.255.254142.193.255.25565,534
195142.194.0.0/16142.194.0.1 to 142.194.255.254142.194.255.25565,534
196142.195.0.0/16142.195.0.1 to 142.195.255.254142.195.255.25565,534
197142.196.0.0/16142.196.0.1 to 142.196.255.254142.196.255.25565,534
198142.197.0.0/16142.197.0.1 to 142.197.255.254142.197.255.25565,534
199142.198.0.0/16142.198.0.1 to 142.198.255.254142.198.255.25565,534
200142.199.0.0/16142.199.0.1 to 142.199.255.254142.199.255.25565,534
201142.200.0.0/16142.200.0.1 to 142.200.255.254142.200.255.25565,534
202142.201.0.0/16142.201.0.1 to 142.201.255.254142.201.255.25565,534
203142.202.0.0/16142.202.0.1 to 142.202.255.254142.202.255.25565,534
204142.203.0.0/16142.203.0.1 to 142.203.255.254142.203.255.25565,534
205142.204.0.0/16142.204.0.1 to 142.204.255.254142.204.255.25565,534
206142.205.0.0/16142.205.0.1 to 142.205.255.254142.205.255.25565,534
207142.206.0.0/16142.206.0.1 to 142.206.255.254142.206.255.25565,534
208142.207.0.0/16142.207.0.1 to 142.207.255.254142.207.255.25565,534
209142.208.0.0/16142.208.0.1 to 142.208.255.254142.208.255.25565,534
210142.209.0.0/16142.209.0.1 to 142.209.255.254142.209.255.25565,534
211142.210.0.0/16142.210.0.1 to 142.210.255.254142.210.255.25565,534
212142.211.0.0/16142.211.0.1 to 142.211.255.254142.211.255.25565,534
213142.212.0.0/16142.212.0.1 to 142.212.255.254142.212.255.25565,534
214142.213.0.0/16142.213.0.1 to 142.213.255.254142.213.255.25565,534
215142.214.0.0/16142.214.0.1 to 142.214.255.254142.214.255.25565,534
216142.215.0.0/16142.215.0.1 to 142.215.255.254142.215.255.25565,534
217142.216.0.0/16142.216.0.1 to 142.216.255.254142.216.255.25565,534
218142.217.0.0/16142.217.0.1 to 142.217.255.254142.217.255.25565,534
219142.218.0.0/16142.218.0.1 to 142.218.255.254142.218.255.25565,534
220142.219.0.0/16142.219.0.1 to 142.219.255.254142.219.255.25565,534
221142.220.0.0/16142.220.0.1 to 142.220.255.254142.220.255.25565,534
222142.221.0.0/16142.221.0.1 to 142.221.255.254142.221.255.25565,534
223142.222.0.0/16142.222.0.1 to 142.222.255.254142.222.255.25565,534
224142.223.0.0/16142.223.0.1 to 142.223.255.254142.223.255.25565,534
225142.224.0.0/16142.224.0.1 to 142.224.255.254142.224.255.25565,534
226142.225.0.0/16142.225.0.1 to 142.225.255.254142.225.255.25565,534
227142.226.0.0/16142.226.0.1 to 142.226.255.254142.226.255.25565,534
228142.227.0.0/16142.227.0.1 to 142.227.255.254142.227.255.25565,534
229142.228.0.0/16142.228.0.1 to 142.228.255.254142.228.255.25565,534
230142.229.0.0/16142.229.0.1 to 142.229.255.254142.229.255.25565,534
231142.230.0.0/16142.230.0.1 to 142.230.255.254142.230.255.25565,534
232142.231.0.0/16142.231.0.1 to 142.231.255.254142.231.255.25565,534
233142.232.0.0/16142.232.0.1 to 142.232.255.254142.232.255.25565,534
234142.233.0.0/16142.233.0.1 to 142.233.255.254142.233.255.25565,534
235142.234.0.0/16142.234.0.1 to 142.234.255.254142.234.255.25565,534
236142.235.0.0/16142.235.0.1 to 142.235.255.254142.235.255.25565,534
237142.236.0.0/16142.236.0.1 to 142.236.255.254142.236.255.25565,534
238142.237.0.0/16142.237.0.1 to 142.237.255.254142.237.255.25565,534
239142.238.0.0/16142.238.0.1 to 142.238.255.254142.238.255.25565,534
240142.239.0.0/16142.239.0.1 to 142.239.255.254142.239.255.25565,534
241142.240.0.0/16142.240.0.1 to 142.240.255.254142.240.255.25565,534
242142.241.0.0/16142.241.0.1 to 142.241.255.254142.241.255.25565,534
243142.242.0.0/16142.242.0.1 to 142.242.255.254142.242.255.25565,534
244142.243.0.0/16142.243.0.1 to 142.243.255.254142.243.255.25565,534
245142.244.0.0/16142.244.0.1 to 142.244.255.254142.244.255.25565,534
246142.245.0.0/16142.245.0.1 to 142.245.255.254142.245.255.25565,534
247142.246.0.0/16142.246.0.1 to 142.246.255.254142.246.255.25565,534
248142.247.0.0/16142.247.0.1 to 142.247.255.254142.247.255.25565,534
249142.248.0.0/16142.248.0.1 to 142.248.255.254142.248.255.25565,534
250142.249.0.0/16142.249.0.1 to 142.249.255.254142.249.255.25565,534
251142.250.0.0/16142.250.0.1 to 142.250.255.254142.250.255.25565,534
252142.251.0.0/16142.251.0.1 to 142.251.255.254142.251.255.25565,534
253142.252.0.0/16142.252.0.1 to 142.252.255.254142.252.255.25565,534
254142.253.0.0/16142.253.0.1 to 142.253.255.254142.253.255.25565,534
255142.254.0.0/16142.254.0.1 to 142.254.255.254142.254.255.25565,534
256142.255.0.0/16142.255.0.1 to 142.255.255.254142.255.255.25565,534

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.