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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/15
/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 256 subnets of /15.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1142.0.0.0/15142.0.0.1 to 142.1.255.254142.1.255.255131,070
2142.2.0.0/15142.2.0.1 to 142.3.255.254142.3.255.255131,070
3142.4.0.0/15142.4.0.1 to 142.5.255.254142.5.255.255131,070
4142.6.0.0/15142.6.0.1 to 142.7.255.254142.7.255.255131,070
5142.8.0.0/15142.8.0.1 to 142.9.255.254142.9.255.255131,070
6142.10.0.0/15142.10.0.1 to 142.11.255.254142.11.255.255131,070
7142.12.0.0/15142.12.0.1 to 142.13.255.254142.13.255.255131,070
8142.14.0.0/15142.14.0.1 to 142.15.255.254142.15.255.255131,070
9142.16.0.0/15142.16.0.1 to 142.17.255.254142.17.255.255131,070
10142.18.0.0/15142.18.0.1 to 142.19.255.254142.19.255.255131,070
11142.20.0.0/15142.20.0.1 to 142.21.255.254142.21.255.255131,070
12142.22.0.0/15142.22.0.1 to 142.23.255.254142.23.255.255131,070
13142.24.0.0/15142.24.0.1 to 142.25.255.254142.25.255.255131,070
14142.26.0.0/15142.26.0.1 to 142.27.255.254142.27.255.255131,070
15142.28.0.0/15142.28.0.1 to 142.29.255.254142.29.255.255131,070
16142.30.0.0/15142.30.0.1 to 142.31.255.254142.31.255.255131,070
17142.32.0.0/15142.32.0.1 to 142.33.255.254142.33.255.255131,070
18142.34.0.0/15142.34.0.1 to 142.35.255.254142.35.255.255131,070
19142.36.0.0/15142.36.0.1 to 142.37.255.254142.37.255.255131,070
20142.38.0.0/15142.38.0.1 to 142.39.255.254142.39.255.255131,070
21142.40.0.0/15142.40.0.1 to 142.41.255.254142.41.255.255131,070
22142.42.0.0/15142.42.0.1 to 142.43.255.254142.43.255.255131,070
23142.44.0.0/15142.44.0.1 to 142.45.255.254142.45.255.255131,070
24142.46.0.0/15142.46.0.1 to 142.47.255.254142.47.255.255131,070
25142.48.0.0/15142.48.0.1 to 142.49.255.254142.49.255.255131,070
26142.50.0.0/15142.50.0.1 to 142.51.255.254142.51.255.255131,070
27142.52.0.0/15142.52.0.1 to 142.53.255.254142.53.255.255131,070
28142.54.0.0/15142.54.0.1 to 142.55.255.254142.55.255.255131,070
29142.56.0.0/15142.56.0.1 to 142.57.255.254142.57.255.255131,070
30142.58.0.0/15142.58.0.1 to 142.59.255.254142.59.255.255131,070
31142.60.0.0/15142.60.0.1 to 142.61.255.254142.61.255.255131,070
32142.62.0.0/15142.62.0.1 to 142.63.255.254142.63.255.255131,070
33142.64.0.0/15142.64.0.1 to 142.65.255.254142.65.255.255131,070
34142.66.0.0/15142.66.0.1 to 142.67.255.254142.67.255.255131,070
35142.68.0.0/15142.68.0.1 to 142.69.255.254142.69.255.255131,070
36142.70.0.0/15142.70.0.1 to 142.71.255.254142.71.255.255131,070
37142.72.0.0/15142.72.0.1 to 142.73.255.254142.73.255.255131,070
38142.74.0.0/15142.74.0.1 to 142.75.255.254142.75.255.255131,070
39142.76.0.0/15142.76.0.1 to 142.77.255.254142.77.255.255131,070
40142.78.0.0/15142.78.0.1 to 142.79.255.254142.79.255.255131,070
41142.80.0.0/15142.80.0.1 to 142.81.255.254142.81.255.255131,070
42142.82.0.0/15142.82.0.1 to 142.83.255.254142.83.255.255131,070
43142.84.0.0/15142.84.0.1 to 142.85.255.254142.85.255.255131,070
44142.86.0.0/15142.86.0.1 to 142.87.255.254142.87.255.255131,070
45142.88.0.0/15142.88.0.1 to 142.89.255.254142.89.255.255131,070
46142.90.0.0/15142.90.0.1 to 142.91.255.254142.91.255.255131,070
47142.92.0.0/15142.92.0.1 to 142.93.255.254142.93.255.255131,070
48142.94.0.0/15142.94.0.1 to 142.95.255.254142.95.255.255131,070
49142.96.0.0/15142.96.0.1 to 142.97.255.254142.97.255.255131,070
50142.98.0.0/15142.98.0.1 to 142.99.255.254142.99.255.255131,070
51142.100.0.0/15142.100.0.1 to 142.101.255.254142.101.255.255131,070
52142.102.0.0/15142.102.0.1 to 142.103.255.254142.103.255.255131,070
53142.104.0.0/15142.104.0.1 to 142.105.255.254142.105.255.255131,070
54142.106.0.0/15142.106.0.1 to 142.107.255.254142.107.255.255131,070
55142.108.0.0/15142.108.0.1 to 142.109.255.254142.109.255.255131,070
56142.110.0.0/15142.110.0.1 to 142.111.255.254142.111.255.255131,070
57142.112.0.0/15142.112.0.1 to 142.113.255.254142.113.255.255131,070
58142.114.0.0/15142.114.0.1 to 142.115.255.254142.115.255.255131,070
59142.116.0.0/15142.116.0.1 to 142.117.255.254142.117.255.255131,070
60142.118.0.0/15142.118.0.1 to 142.119.255.254142.119.255.255131,070
61142.120.0.0/15142.120.0.1 to 142.121.255.254142.121.255.255131,070
62142.122.0.0/15142.122.0.1 to 142.123.255.254142.123.255.255131,070
63142.124.0.0/15142.124.0.1 to 142.125.255.254142.125.255.255131,070
64142.126.0.0/15142.126.0.1 to 142.127.255.254142.127.255.255131,070
65142.128.0.0/15142.128.0.1 to 142.129.255.254142.129.255.255131,070
66142.130.0.0/15142.130.0.1 to 142.131.255.254142.131.255.255131,070
67142.132.0.0/15142.132.0.1 to 142.133.255.254142.133.255.255131,070
68142.134.0.0/15142.134.0.1 to 142.135.255.254142.135.255.255131,070
69142.136.0.0/15142.136.0.1 to 142.137.255.254142.137.255.255131,070
70142.138.0.0/15142.138.0.1 to 142.139.255.254142.139.255.255131,070
71142.140.0.0/15142.140.0.1 to 142.141.255.254142.141.255.255131,070
72142.142.0.0/15142.142.0.1 to 142.143.255.254142.143.255.255131,070
73142.144.0.0/15142.144.0.1 to 142.145.255.254142.145.255.255131,070
74142.146.0.0/15142.146.0.1 to 142.147.255.254142.147.255.255131,070
75142.148.0.0/15142.148.0.1 to 142.149.255.254142.149.255.255131,070
76142.150.0.0/15142.150.0.1 to 142.151.255.254142.151.255.255131,070
77142.152.0.0/15142.152.0.1 to 142.153.255.254142.153.255.255131,070
78142.154.0.0/15142.154.0.1 to 142.155.255.254142.155.255.255131,070
79142.156.0.0/15142.156.0.1 to 142.157.255.254142.157.255.255131,070
80142.158.0.0/15142.158.0.1 to 142.159.255.254142.159.255.255131,070
81142.160.0.0/15142.160.0.1 to 142.161.255.254142.161.255.255131,070
82142.162.0.0/15142.162.0.1 to 142.163.255.254142.163.255.255131,070
83142.164.0.0/15142.164.0.1 to 142.165.255.254142.165.255.255131,070
84142.166.0.0/15142.166.0.1 to 142.167.255.254142.167.255.255131,070
85142.168.0.0/15142.168.0.1 to 142.169.255.254142.169.255.255131,070
86142.170.0.0/15142.170.0.1 to 142.171.255.254142.171.255.255131,070
87142.172.0.0/15142.172.0.1 to 142.173.255.254142.173.255.255131,070
88142.174.0.0/15142.174.0.1 to 142.175.255.254142.175.255.255131,070
89142.176.0.0/15142.176.0.1 to 142.177.255.254142.177.255.255131,070
90142.178.0.0/15142.178.0.1 to 142.179.255.254142.179.255.255131,070
91142.180.0.0/15142.180.0.1 to 142.181.255.254142.181.255.255131,070
92142.182.0.0/15142.182.0.1 to 142.183.255.254142.183.255.255131,070
93142.184.0.0/15142.184.0.1 to 142.185.255.254142.185.255.255131,070
94142.186.0.0/15142.186.0.1 to 142.187.255.254142.187.255.255131,070
95142.188.0.0/15142.188.0.1 to 142.189.255.254142.189.255.255131,070
96142.190.0.0/15142.190.0.1 to 142.191.255.254142.191.255.255131,070
97142.192.0.0/15142.192.0.1 to 142.193.255.254142.193.255.255131,070
98142.194.0.0/15142.194.0.1 to 142.195.255.254142.195.255.255131,070
99142.196.0.0/15142.196.0.1 to 142.197.255.254142.197.255.255131,070
100142.198.0.0/15142.198.0.1 to 142.199.255.254142.199.255.255131,070
101142.200.0.0/15142.200.0.1 to 142.201.255.254142.201.255.255131,070
102142.202.0.0/15142.202.0.1 to 142.203.255.254142.203.255.255131,070
103142.204.0.0/15142.204.0.1 to 142.205.255.254142.205.255.255131,070
104142.206.0.0/15142.206.0.1 to 142.207.255.254142.207.255.255131,070
105142.208.0.0/15142.208.0.1 to 142.209.255.254142.209.255.255131,070
106142.210.0.0/15142.210.0.1 to 142.211.255.254142.211.255.255131,070
107142.212.0.0/15142.212.0.1 to 142.213.255.254142.213.255.255131,070
108142.214.0.0/15142.214.0.1 to 142.215.255.254142.215.255.255131,070
109142.216.0.0/15142.216.0.1 to 142.217.255.254142.217.255.255131,070
110142.218.0.0/15142.218.0.1 to 142.219.255.254142.219.255.255131,070
111142.220.0.0/15142.220.0.1 to 142.221.255.254142.221.255.255131,070
112142.222.0.0/15142.222.0.1 to 142.223.255.254142.223.255.255131,070
113142.224.0.0/15142.224.0.1 to 142.225.255.254142.225.255.255131,070
114142.226.0.0/15142.226.0.1 to 142.227.255.254142.227.255.255131,070
115142.228.0.0/15142.228.0.1 to 142.229.255.254142.229.255.255131,070
116142.230.0.0/15142.230.0.1 to 142.231.255.254142.231.255.255131,070
117142.232.0.0/15142.232.0.1 to 142.233.255.254142.233.255.255131,070
118142.234.0.0/15142.234.0.1 to 142.235.255.254142.235.255.255131,070
119142.236.0.0/15142.236.0.1 to 142.237.255.254142.237.255.255131,070
120142.238.0.0/15142.238.0.1 to 142.239.255.254142.239.255.255131,070
121142.240.0.0/15142.240.0.1 to 142.241.255.254142.241.255.255131,070
122142.242.0.0/15142.242.0.1 to 142.243.255.254142.243.255.255131,070
123142.244.0.0/15142.244.0.1 to 142.245.255.254142.245.255.255131,070
124142.246.0.0/15142.246.0.1 to 142.247.255.254142.247.255.255131,070
125142.248.0.0/15142.248.0.1 to 142.249.255.254142.249.255.255131,070
126142.250.0.0/15142.250.0.1 to 142.251.255.254142.251.255.255131,070
127142.252.0.0/15142.252.0.1 to 142.253.255.254142.253.255.255131,070
128142.254.0.0/15142.254.0.1 to 142.255.255.254142.255.255.255131,070
129143.0.0.0/15143.0.0.1 to 143.1.255.254143.1.255.255131,070
130143.2.0.0/15143.2.0.1 to 143.3.255.254143.3.255.255131,070
131143.4.0.0/15143.4.0.1 to 143.5.255.254143.5.255.255131,070
132143.6.0.0/15143.6.0.1 to 143.7.255.254143.7.255.255131,070
133143.8.0.0/15143.8.0.1 to 143.9.255.254143.9.255.255131,070
134143.10.0.0/15143.10.0.1 to 143.11.255.254143.11.255.255131,070
135143.12.0.0/15143.12.0.1 to 143.13.255.254143.13.255.255131,070
136143.14.0.0/15143.14.0.1 to 143.15.255.254143.15.255.255131,070
137143.16.0.0/15143.16.0.1 to 143.17.255.254143.17.255.255131,070
138143.18.0.0/15143.18.0.1 to 143.19.255.254143.19.255.255131,070
139143.20.0.0/15143.20.0.1 to 143.21.255.254143.21.255.255131,070
140143.22.0.0/15143.22.0.1 to 143.23.255.254143.23.255.255131,070
141143.24.0.0/15143.24.0.1 to 143.25.255.254143.25.255.255131,070
142143.26.0.0/15143.26.0.1 to 143.27.255.254143.27.255.255131,070
143143.28.0.0/15143.28.0.1 to 143.29.255.254143.29.255.255131,070
144143.30.0.0/15143.30.0.1 to 143.31.255.254143.31.255.255131,070
145143.32.0.0/15143.32.0.1 to 143.33.255.254143.33.255.255131,070
146143.34.0.0/15143.34.0.1 to 143.35.255.254143.35.255.255131,070
147143.36.0.0/15143.36.0.1 to 143.37.255.254143.37.255.255131,070
148143.38.0.0/15143.38.0.1 to 143.39.255.254143.39.255.255131,070
149143.40.0.0/15143.40.0.1 to 143.41.255.254143.41.255.255131,070
150143.42.0.0/15143.42.0.1 to 143.43.255.254143.43.255.255131,070
151143.44.0.0/15143.44.0.1 to 143.45.255.254143.45.255.255131,070
152143.46.0.0/15143.46.0.1 to 143.47.255.254143.47.255.255131,070
153143.48.0.0/15143.48.0.1 to 143.49.255.254143.49.255.255131,070
154143.50.0.0/15143.50.0.1 to 143.51.255.254143.51.255.255131,070
155143.52.0.0/15143.52.0.1 to 143.53.255.254143.53.255.255131,070
156143.54.0.0/15143.54.0.1 to 143.55.255.254143.55.255.255131,070
157143.56.0.0/15143.56.0.1 to 143.57.255.254143.57.255.255131,070
158143.58.0.0/15143.58.0.1 to 143.59.255.254143.59.255.255131,070
159143.60.0.0/15143.60.0.1 to 143.61.255.254143.61.255.255131,070
160143.62.0.0/15143.62.0.1 to 143.63.255.254143.63.255.255131,070
161143.64.0.0/15143.64.0.1 to 143.65.255.254143.65.255.255131,070
162143.66.0.0/15143.66.0.1 to 143.67.255.254143.67.255.255131,070
163143.68.0.0/15143.68.0.1 to 143.69.255.254143.69.255.255131,070
164143.70.0.0/15143.70.0.1 to 143.71.255.254143.71.255.255131,070
165143.72.0.0/15143.72.0.1 to 143.73.255.254143.73.255.255131,070
166143.74.0.0/15143.74.0.1 to 143.75.255.254143.75.255.255131,070
167143.76.0.0/15143.76.0.1 to 143.77.255.254143.77.255.255131,070
168143.78.0.0/15143.78.0.1 to 143.79.255.254143.79.255.255131,070
169143.80.0.0/15143.80.0.1 to 143.81.255.254143.81.255.255131,070
170143.82.0.0/15143.82.0.1 to 143.83.255.254143.83.255.255131,070
171143.84.0.0/15143.84.0.1 to 143.85.255.254143.85.255.255131,070
172143.86.0.0/15143.86.0.1 to 143.87.255.254143.87.255.255131,070
173143.88.0.0/15143.88.0.1 to 143.89.255.254143.89.255.255131,070
174143.90.0.0/15143.90.0.1 to 143.91.255.254143.91.255.255131,070
175143.92.0.0/15143.92.0.1 to 143.93.255.254143.93.255.255131,070
176143.94.0.0/15143.94.0.1 to 143.95.255.254143.95.255.255131,070
177143.96.0.0/15143.96.0.1 to 143.97.255.254143.97.255.255131,070
178143.98.0.0/15143.98.0.1 to 143.99.255.254143.99.255.255131,070
179143.100.0.0/15143.100.0.1 to 143.101.255.254143.101.255.255131,070
180143.102.0.0/15143.102.0.1 to 143.103.255.254143.103.255.255131,070
181143.104.0.0/15143.104.0.1 to 143.105.255.254143.105.255.255131,070
182143.106.0.0/15143.106.0.1 to 143.107.255.254143.107.255.255131,070
183143.108.0.0/15143.108.0.1 to 143.109.255.254143.109.255.255131,070
184143.110.0.0/15143.110.0.1 to 143.111.255.254143.111.255.255131,070
185143.112.0.0/15143.112.0.1 to 143.113.255.254143.113.255.255131,070
186143.114.0.0/15143.114.0.1 to 143.115.255.254143.115.255.255131,070
187143.116.0.0/15143.116.0.1 to 143.117.255.254143.117.255.255131,070
188143.118.0.0/15143.118.0.1 to 143.119.255.254143.119.255.255131,070
189143.120.0.0/15143.120.0.1 to 143.121.255.254143.121.255.255131,070
190143.122.0.0/15143.122.0.1 to 143.123.255.254143.123.255.255131,070
191143.124.0.0/15143.124.0.1 to 143.125.255.254143.125.255.255131,070
192143.126.0.0/15143.126.0.1 to 143.127.255.254143.127.255.255131,070
193143.128.0.0/15143.128.0.1 to 143.129.255.254143.129.255.255131,070
194143.130.0.0/15143.130.0.1 to 143.131.255.254143.131.255.255131,070
195143.132.0.0/15143.132.0.1 to 143.133.255.254143.133.255.255131,070
196143.134.0.0/15143.134.0.1 to 143.135.255.254143.135.255.255131,070
197143.136.0.0/15143.136.0.1 to 143.137.255.254143.137.255.255131,070
198143.138.0.0/15143.138.0.1 to 143.139.255.254143.139.255.255131,070
199143.140.0.0/15143.140.0.1 to 143.141.255.254143.141.255.255131,070
200143.142.0.0/15143.142.0.1 to 143.143.255.254143.143.255.255131,070
201143.144.0.0/15143.144.0.1 to 143.145.255.254143.145.255.255131,070
202143.146.0.0/15143.146.0.1 to 143.147.255.254143.147.255.255131,070
203143.148.0.0/15143.148.0.1 to 143.149.255.254143.149.255.255131,070
204143.150.0.0/15143.150.0.1 to 143.151.255.254143.151.255.255131,070
205143.152.0.0/15143.152.0.1 to 143.153.255.254143.153.255.255131,070
206143.154.0.0/15143.154.0.1 to 143.155.255.254143.155.255.255131,070
207143.156.0.0/15143.156.0.1 to 143.157.255.254143.157.255.255131,070
208143.158.0.0/15143.158.0.1 to 143.159.255.254143.159.255.255131,070
209143.160.0.0/15143.160.0.1 to 143.161.255.254143.161.255.255131,070
210143.162.0.0/15143.162.0.1 to 143.163.255.254143.163.255.255131,070
211143.164.0.0/15143.164.0.1 to 143.165.255.254143.165.255.255131,070
212143.166.0.0/15143.166.0.1 to 143.167.255.254143.167.255.255131,070
213143.168.0.0/15143.168.0.1 to 143.169.255.254143.169.255.255131,070
214143.170.0.0/15143.170.0.1 to 143.171.255.254143.171.255.255131,070
215143.172.0.0/15143.172.0.1 to 143.173.255.254143.173.255.255131,070
216143.174.0.0/15143.174.0.1 to 143.175.255.254143.175.255.255131,070
217143.176.0.0/15143.176.0.1 to 143.177.255.254143.177.255.255131,070
218143.178.0.0/15143.178.0.1 to 143.179.255.254143.179.255.255131,070
219143.180.0.0/15143.180.0.1 to 143.181.255.254143.181.255.255131,070
220143.182.0.0/15143.182.0.1 to 143.183.255.254143.183.255.255131,070
221143.184.0.0/15143.184.0.1 to 143.185.255.254143.185.255.255131,070
222143.186.0.0/15143.186.0.1 to 143.187.255.254143.187.255.255131,070
223143.188.0.0/15143.188.0.1 to 143.189.255.254143.189.255.255131,070
224143.190.0.0/15143.190.0.1 to 143.191.255.254143.191.255.255131,070
225143.192.0.0/15143.192.0.1 to 143.193.255.254143.193.255.255131,070
226143.194.0.0/15143.194.0.1 to 143.195.255.254143.195.255.255131,070
227143.196.0.0/15143.196.0.1 to 143.197.255.254143.197.255.255131,070
228143.198.0.0/15143.198.0.1 to 143.199.255.254143.199.255.255131,070
229143.200.0.0/15143.200.0.1 to 143.201.255.254143.201.255.255131,070
230143.202.0.0/15143.202.0.1 to 143.203.255.254143.203.255.255131,070
231143.204.0.0/15143.204.0.1 to 143.205.255.254143.205.255.255131,070
232143.206.0.0/15143.206.0.1 to 143.207.255.254143.207.255.255131,070
233143.208.0.0/15143.208.0.1 to 143.209.255.254143.209.255.255131,070
234143.210.0.0/15143.210.0.1 to 143.211.255.254143.211.255.255131,070
235143.212.0.0/15143.212.0.1 to 143.213.255.254143.213.255.255131,070
236143.214.0.0/15143.214.0.1 to 143.215.255.254143.215.255.255131,070
237143.216.0.0/15143.216.0.1 to 143.217.255.254143.217.255.255131,070
238143.218.0.0/15143.218.0.1 to 143.219.255.254143.219.255.255131,070
239143.220.0.0/15143.220.0.1 to 143.221.255.254143.221.255.255131,070
240143.222.0.0/15143.222.0.1 to 143.223.255.254143.223.255.255131,070
241143.224.0.0/15143.224.0.1 to 143.225.255.254143.225.255.255131,070
242143.226.0.0/15143.226.0.1 to 143.227.255.254143.227.255.255131,070
243143.228.0.0/15143.228.0.1 to 143.229.255.254143.229.255.255131,070
244143.230.0.0/15143.230.0.1 to 143.231.255.254143.231.255.255131,070
245143.232.0.0/15143.232.0.1 to 143.233.255.254143.233.255.255131,070
246143.234.0.0/15143.234.0.1 to 143.235.255.254143.235.255.255131,070
247143.236.0.0/15143.236.0.1 to 143.237.255.254143.237.255.255131,070
248143.238.0.0/15143.238.0.1 to 143.239.255.254143.239.255.255131,070
249143.240.0.0/15143.240.0.1 to 143.241.255.254143.241.255.255131,070
250143.242.0.0/15143.242.0.1 to 143.243.255.254143.243.255.255131,070
251143.244.0.0/15143.244.0.1 to 143.245.255.254143.245.255.255131,070
252143.246.0.0/15143.246.0.1 to 143.247.255.254143.247.255.255131,070
253143.248.0.0/15143.248.0.1 to 143.249.255.254143.249.255.255131,070
254143.250.0.0/15143.250.0.1 to 143.251.255.254143.251.255.255131,070
255143.252.0.0/15143.252.0.1 to 143.253.255.254143.253.255.255131,070
256143.254.0.0/15143.254.0.1 to 143.255.255.254143.255.255.255131,070

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.