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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.

Network103.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
103.0.0.0
Broadcast address
103.255.255.255
First usable
103.0.0.1
Last usable
103.255.255.254
Usable hosts
16,777,214 (16,777,216 less the network and broadcast addresses)
Subnet mask
255.0.0.0
Wildcard mask
0.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/8
Type
Public public
Old class
A (default /8)
As numbers
Hex 67000000 · Integer 1728053248 to 1744830463
Reverse DNS zone
103.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01100111..00000000.00000000.00000000103.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network01100111..00000000.00000000.00000000103.0.0.0
Broadcast01100111..11111111.11111111.11111111103.255.255.255
Split into smaller subnets/16
/9 (2)/10 (4)/11 (8)/12 (16)/13 (32)/14 (64)/15 (128)/16 (256)/17 (512)/18 (1,024)/19 (2,048)/20 (4,096)

103.0.0.0/8 makes 256 subnets of /16.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1103.0.0.0/16103.0.0.1 to 103.0.255.254103.0.255.25565,534
2103.1.0.0/16103.1.0.1 to 103.1.255.254103.1.255.25565,534
3103.2.0.0/16103.2.0.1 to 103.2.255.254103.2.255.25565,534
4103.3.0.0/16103.3.0.1 to 103.3.255.254103.3.255.25565,534
5103.4.0.0/16103.4.0.1 to 103.4.255.254103.4.255.25565,534
6103.5.0.0/16103.5.0.1 to 103.5.255.254103.5.255.25565,534
7103.6.0.0/16103.6.0.1 to 103.6.255.254103.6.255.25565,534
8103.7.0.0/16103.7.0.1 to 103.7.255.254103.7.255.25565,534
9103.8.0.0/16103.8.0.1 to 103.8.255.254103.8.255.25565,534
10103.9.0.0/16103.9.0.1 to 103.9.255.254103.9.255.25565,534
11103.10.0.0/16103.10.0.1 to 103.10.255.254103.10.255.25565,534
12103.11.0.0/16103.11.0.1 to 103.11.255.254103.11.255.25565,534
13103.12.0.0/16103.12.0.1 to 103.12.255.254103.12.255.25565,534
14103.13.0.0/16103.13.0.1 to 103.13.255.254103.13.255.25565,534
15103.14.0.0/16103.14.0.1 to 103.14.255.254103.14.255.25565,534
16103.15.0.0/16103.15.0.1 to 103.15.255.254103.15.255.25565,534
17103.16.0.0/16103.16.0.1 to 103.16.255.254103.16.255.25565,534
18103.17.0.0/16103.17.0.1 to 103.17.255.254103.17.255.25565,534
19103.18.0.0/16103.18.0.1 to 103.18.255.254103.18.255.25565,534
20103.19.0.0/16103.19.0.1 to 103.19.255.254103.19.255.25565,534
21103.20.0.0/16103.20.0.1 to 103.20.255.254103.20.255.25565,534
22103.21.0.0/16103.21.0.1 to 103.21.255.254103.21.255.25565,534
23103.22.0.0/16103.22.0.1 to 103.22.255.254103.22.255.25565,534
24103.23.0.0/16103.23.0.1 to 103.23.255.254103.23.255.25565,534
25103.24.0.0/16103.24.0.1 to 103.24.255.254103.24.255.25565,534
26103.25.0.0/16103.25.0.1 to 103.25.255.254103.25.255.25565,534
27103.26.0.0/16103.26.0.1 to 103.26.255.254103.26.255.25565,534
28103.27.0.0/16103.27.0.1 to 103.27.255.254103.27.255.25565,534
29103.28.0.0/16103.28.0.1 to 103.28.255.254103.28.255.25565,534
30103.29.0.0/16103.29.0.1 to 103.29.255.254103.29.255.25565,534
31103.30.0.0/16103.30.0.1 to 103.30.255.254103.30.255.25565,534
32103.31.0.0/16103.31.0.1 to 103.31.255.254103.31.255.25565,534
33103.32.0.0/16103.32.0.1 to 103.32.255.254103.32.255.25565,534
34103.33.0.0/16103.33.0.1 to 103.33.255.254103.33.255.25565,534
35103.34.0.0/16103.34.0.1 to 103.34.255.254103.34.255.25565,534
36103.35.0.0/16103.35.0.1 to 103.35.255.254103.35.255.25565,534
37103.36.0.0/16103.36.0.1 to 103.36.255.254103.36.255.25565,534
38103.37.0.0/16103.37.0.1 to 103.37.255.254103.37.255.25565,534
39103.38.0.0/16103.38.0.1 to 103.38.255.254103.38.255.25565,534
40103.39.0.0/16103.39.0.1 to 103.39.255.254103.39.255.25565,534
41103.40.0.0/16103.40.0.1 to 103.40.255.254103.40.255.25565,534
42103.41.0.0/16103.41.0.1 to 103.41.255.254103.41.255.25565,534
43103.42.0.0/16103.42.0.1 to 103.42.255.254103.42.255.25565,534
44103.43.0.0/16103.43.0.1 to 103.43.255.254103.43.255.25565,534
45103.44.0.0/16103.44.0.1 to 103.44.255.254103.44.255.25565,534
46103.45.0.0/16103.45.0.1 to 103.45.255.254103.45.255.25565,534
47103.46.0.0/16103.46.0.1 to 103.46.255.254103.46.255.25565,534
48103.47.0.0/16103.47.0.1 to 103.47.255.254103.47.255.25565,534
49103.48.0.0/16103.48.0.1 to 103.48.255.254103.48.255.25565,534
50103.49.0.0/16103.49.0.1 to 103.49.255.254103.49.255.25565,534
51103.50.0.0/16103.50.0.1 to 103.50.255.254103.50.255.25565,534
52103.51.0.0/16103.51.0.1 to 103.51.255.254103.51.255.25565,534
53103.52.0.0/16103.52.0.1 to 103.52.255.254103.52.255.25565,534
54103.53.0.0/16103.53.0.1 to 103.53.255.254103.53.255.25565,534
55103.54.0.0/16103.54.0.1 to 103.54.255.254103.54.255.25565,534
56103.55.0.0/16103.55.0.1 to 103.55.255.254103.55.255.25565,534
57103.56.0.0/16103.56.0.1 to 103.56.255.254103.56.255.25565,534
58103.57.0.0/16103.57.0.1 to 103.57.255.254103.57.255.25565,534
59103.58.0.0/16103.58.0.1 to 103.58.255.254103.58.255.25565,534
60103.59.0.0/16103.59.0.1 to 103.59.255.254103.59.255.25565,534
61103.60.0.0/16103.60.0.1 to 103.60.255.254103.60.255.25565,534
62103.61.0.0/16103.61.0.1 to 103.61.255.254103.61.255.25565,534
63103.62.0.0/16103.62.0.1 to 103.62.255.254103.62.255.25565,534
64103.63.0.0/16103.63.0.1 to 103.63.255.254103.63.255.25565,534
65103.64.0.0/16103.64.0.1 to 103.64.255.254103.64.255.25565,534
66103.65.0.0/16103.65.0.1 to 103.65.255.254103.65.255.25565,534
67103.66.0.0/16103.66.0.1 to 103.66.255.254103.66.255.25565,534
68103.67.0.0/16103.67.0.1 to 103.67.255.254103.67.255.25565,534
69103.68.0.0/16103.68.0.1 to 103.68.255.254103.68.255.25565,534
70103.69.0.0/16103.69.0.1 to 103.69.255.254103.69.255.25565,534
71103.70.0.0/16103.70.0.1 to 103.70.255.254103.70.255.25565,534
72103.71.0.0/16103.71.0.1 to 103.71.255.254103.71.255.25565,534
73103.72.0.0/16103.72.0.1 to 103.72.255.254103.72.255.25565,534
74103.73.0.0/16103.73.0.1 to 103.73.255.254103.73.255.25565,534
75103.74.0.0/16103.74.0.1 to 103.74.255.254103.74.255.25565,534
76103.75.0.0/16103.75.0.1 to 103.75.255.254103.75.255.25565,534
77103.76.0.0/16103.76.0.1 to 103.76.255.254103.76.255.25565,534
78103.77.0.0/16103.77.0.1 to 103.77.255.254103.77.255.25565,534
79103.78.0.0/16103.78.0.1 to 103.78.255.254103.78.255.25565,534
80103.79.0.0/16103.79.0.1 to 103.79.255.254103.79.255.25565,534
81103.80.0.0/16103.80.0.1 to 103.80.255.254103.80.255.25565,534
82103.81.0.0/16103.81.0.1 to 103.81.255.254103.81.255.25565,534
83103.82.0.0/16103.82.0.1 to 103.82.255.254103.82.255.25565,534
84103.83.0.0/16103.83.0.1 to 103.83.255.254103.83.255.25565,534
85103.84.0.0/16103.84.0.1 to 103.84.255.254103.84.255.25565,534
86103.85.0.0/16103.85.0.1 to 103.85.255.254103.85.255.25565,534
87103.86.0.0/16103.86.0.1 to 103.86.255.254103.86.255.25565,534
88103.87.0.0/16103.87.0.1 to 103.87.255.254103.87.255.25565,534
89103.88.0.0/16103.88.0.1 to 103.88.255.254103.88.255.25565,534
90103.89.0.0/16103.89.0.1 to 103.89.255.254103.89.255.25565,534
91103.90.0.0/16103.90.0.1 to 103.90.255.254103.90.255.25565,534
92103.91.0.0/16103.91.0.1 to 103.91.255.254103.91.255.25565,534
93103.92.0.0/16103.92.0.1 to 103.92.255.254103.92.255.25565,534
94103.93.0.0/16103.93.0.1 to 103.93.255.254103.93.255.25565,534
95103.94.0.0/16103.94.0.1 to 103.94.255.254103.94.255.25565,534
96103.95.0.0/16103.95.0.1 to 103.95.255.254103.95.255.25565,534
97103.96.0.0/16103.96.0.1 to 103.96.255.254103.96.255.25565,534
98103.97.0.0/16103.97.0.1 to 103.97.255.254103.97.255.25565,534
99103.98.0.0/16103.98.0.1 to 103.98.255.254103.98.255.25565,534
100103.99.0.0/16103.99.0.1 to 103.99.255.254103.99.255.25565,534
101103.100.0.0/16103.100.0.1 to 103.100.255.254103.100.255.25565,534
102103.101.0.0/16103.101.0.1 to 103.101.255.254103.101.255.25565,534
103103.102.0.0/16103.102.0.1 to 103.102.255.254103.102.255.25565,534
104103.103.0.0/16103.103.0.1 to 103.103.255.254103.103.255.25565,534
105103.104.0.0/16103.104.0.1 to 103.104.255.254103.104.255.25565,534
106103.105.0.0/16103.105.0.1 to 103.105.255.254103.105.255.25565,534
107103.106.0.0/16103.106.0.1 to 103.106.255.254103.106.255.25565,534
108103.107.0.0/16103.107.0.1 to 103.107.255.254103.107.255.25565,534
109103.108.0.0/16103.108.0.1 to 103.108.255.254103.108.255.25565,534
110103.109.0.0/16103.109.0.1 to 103.109.255.254103.109.255.25565,534
111103.110.0.0/16103.110.0.1 to 103.110.255.254103.110.255.25565,534
112103.111.0.0/16103.111.0.1 to 103.111.255.254103.111.255.25565,534
113103.112.0.0/16103.112.0.1 to 103.112.255.254103.112.255.25565,534
114103.113.0.0/16103.113.0.1 to 103.113.255.254103.113.255.25565,534
115103.114.0.0/16103.114.0.1 to 103.114.255.254103.114.255.25565,534
116103.115.0.0/16103.115.0.1 to 103.115.255.254103.115.255.25565,534
117103.116.0.0/16103.116.0.1 to 103.116.255.254103.116.255.25565,534
118103.117.0.0/16103.117.0.1 to 103.117.255.254103.117.255.25565,534
119103.118.0.0/16103.118.0.1 to 103.118.255.254103.118.255.25565,534
120103.119.0.0/16103.119.0.1 to 103.119.255.254103.119.255.25565,534
121103.120.0.0/16103.120.0.1 to 103.120.255.254103.120.255.25565,534
122103.121.0.0/16103.121.0.1 to 103.121.255.254103.121.255.25565,534
123103.122.0.0/16103.122.0.1 to 103.122.255.254103.122.255.25565,534
124103.123.0.0/16103.123.0.1 to 103.123.255.254103.123.255.25565,534
125103.124.0.0/16103.124.0.1 to 103.124.255.254103.124.255.25565,534
126103.125.0.0/16103.125.0.1 to 103.125.255.254103.125.255.25565,534
127103.126.0.0/16103.126.0.1 to 103.126.255.254103.126.255.25565,534
128103.127.0.0/16103.127.0.1 to 103.127.255.254103.127.255.25565,534
129103.128.0.0/16103.128.0.1 to 103.128.255.254103.128.255.25565,534
130103.129.0.0/16103.129.0.1 to 103.129.255.254103.129.255.25565,534
131103.130.0.0/16103.130.0.1 to 103.130.255.254103.130.255.25565,534
132103.131.0.0/16103.131.0.1 to 103.131.255.254103.131.255.25565,534
133103.132.0.0/16103.132.0.1 to 103.132.255.254103.132.255.25565,534
134103.133.0.0/16103.133.0.1 to 103.133.255.254103.133.255.25565,534
135103.134.0.0/16103.134.0.1 to 103.134.255.254103.134.255.25565,534
136103.135.0.0/16103.135.0.1 to 103.135.255.254103.135.255.25565,534
137103.136.0.0/16103.136.0.1 to 103.136.255.254103.136.255.25565,534
138103.137.0.0/16103.137.0.1 to 103.137.255.254103.137.255.25565,534
139103.138.0.0/16103.138.0.1 to 103.138.255.254103.138.255.25565,534
140103.139.0.0/16103.139.0.1 to 103.139.255.254103.139.255.25565,534
141103.140.0.0/16103.140.0.1 to 103.140.255.254103.140.255.25565,534
142103.141.0.0/16103.141.0.1 to 103.141.255.254103.141.255.25565,534
143103.142.0.0/16103.142.0.1 to 103.142.255.254103.142.255.25565,534
144103.143.0.0/16103.143.0.1 to 103.143.255.254103.143.255.25565,534
145103.144.0.0/16103.144.0.1 to 103.144.255.254103.144.255.25565,534
146103.145.0.0/16103.145.0.1 to 103.145.255.254103.145.255.25565,534
147103.146.0.0/16103.146.0.1 to 103.146.255.254103.146.255.25565,534
148103.147.0.0/16103.147.0.1 to 103.147.255.254103.147.255.25565,534
149103.148.0.0/16103.148.0.1 to 103.148.255.254103.148.255.25565,534
150103.149.0.0/16103.149.0.1 to 103.149.255.254103.149.255.25565,534
151103.150.0.0/16103.150.0.1 to 103.150.255.254103.150.255.25565,534
152103.151.0.0/16103.151.0.1 to 103.151.255.254103.151.255.25565,534
153103.152.0.0/16103.152.0.1 to 103.152.255.254103.152.255.25565,534
154103.153.0.0/16103.153.0.1 to 103.153.255.254103.153.255.25565,534
155103.154.0.0/16103.154.0.1 to 103.154.255.254103.154.255.25565,534
156103.155.0.0/16103.155.0.1 to 103.155.255.254103.155.255.25565,534
157103.156.0.0/16103.156.0.1 to 103.156.255.254103.156.255.25565,534
158103.157.0.0/16103.157.0.1 to 103.157.255.254103.157.255.25565,534
159103.158.0.0/16103.158.0.1 to 103.158.255.254103.158.255.25565,534
160103.159.0.0/16103.159.0.1 to 103.159.255.254103.159.255.25565,534
161103.160.0.0/16103.160.0.1 to 103.160.255.254103.160.255.25565,534
162103.161.0.0/16103.161.0.1 to 103.161.255.254103.161.255.25565,534
163103.162.0.0/16103.162.0.1 to 103.162.255.254103.162.255.25565,534
164103.163.0.0/16103.163.0.1 to 103.163.255.254103.163.255.25565,534
165103.164.0.0/16103.164.0.1 to 103.164.255.254103.164.255.25565,534
166103.165.0.0/16103.165.0.1 to 103.165.255.254103.165.255.25565,534
167103.166.0.0/16103.166.0.1 to 103.166.255.254103.166.255.25565,534
168103.167.0.0/16103.167.0.1 to 103.167.255.254103.167.255.25565,534
169103.168.0.0/16103.168.0.1 to 103.168.255.254103.168.255.25565,534
170103.169.0.0/16103.169.0.1 to 103.169.255.254103.169.255.25565,534
171103.170.0.0/16103.170.0.1 to 103.170.255.254103.170.255.25565,534
172103.171.0.0/16103.171.0.1 to 103.171.255.254103.171.255.25565,534
173103.172.0.0/16103.172.0.1 to 103.172.255.254103.172.255.25565,534
174103.173.0.0/16103.173.0.1 to 103.173.255.254103.173.255.25565,534
175103.174.0.0/16103.174.0.1 to 103.174.255.254103.174.255.25565,534
176103.175.0.0/16103.175.0.1 to 103.175.255.254103.175.255.25565,534
177103.176.0.0/16103.176.0.1 to 103.176.255.254103.176.255.25565,534
178103.177.0.0/16103.177.0.1 to 103.177.255.254103.177.255.25565,534
179103.178.0.0/16103.178.0.1 to 103.178.255.254103.178.255.25565,534
180103.179.0.0/16103.179.0.1 to 103.179.255.254103.179.255.25565,534
181103.180.0.0/16103.180.0.1 to 103.180.255.254103.180.255.25565,534
182103.181.0.0/16103.181.0.1 to 103.181.255.254103.181.255.25565,534
183103.182.0.0/16103.182.0.1 to 103.182.255.254103.182.255.25565,534
184103.183.0.0/16103.183.0.1 to 103.183.255.254103.183.255.25565,534
185103.184.0.0/16103.184.0.1 to 103.184.255.254103.184.255.25565,534
186103.185.0.0/16103.185.0.1 to 103.185.255.254103.185.255.25565,534
187103.186.0.0/16103.186.0.1 to 103.186.255.254103.186.255.25565,534
188103.187.0.0/16103.187.0.1 to 103.187.255.254103.187.255.25565,534
189103.188.0.0/16103.188.0.1 to 103.188.255.254103.188.255.25565,534
190103.189.0.0/16103.189.0.1 to 103.189.255.254103.189.255.25565,534
191103.190.0.0/16103.190.0.1 to 103.190.255.254103.190.255.25565,534
192103.191.0.0/16103.191.0.1 to 103.191.255.254103.191.255.25565,534
193103.192.0.0/16103.192.0.1 to 103.192.255.254103.192.255.25565,534
194103.193.0.0/16103.193.0.1 to 103.193.255.254103.193.255.25565,534
195103.194.0.0/16103.194.0.1 to 103.194.255.254103.194.255.25565,534
196103.195.0.0/16103.195.0.1 to 103.195.255.254103.195.255.25565,534
197103.196.0.0/16103.196.0.1 to 103.196.255.254103.196.255.25565,534
198103.197.0.0/16103.197.0.1 to 103.197.255.254103.197.255.25565,534
199103.198.0.0/16103.198.0.1 to 103.198.255.254103.198.255.25565,534
200103.199.0.0/16103.199.0.1 to 103.199.255.254103.199.255.25565,534
201103.200.0.0/16103.200.0.1 to 103.200.255.254103.200.255.25565,534
202103.201.0.0/16103.201.0.1 to 103.201.255.254103.201.255.25565,534
203103.202.0.0/16103.202.0.1 to 103.202.255.254103.202.255.25565,534
204103.203.0.0/16103.203.0.1 to 103.203.255.254103.203.255.25565,534
205103.204.0.0/16103.204.0.1 to 103.204.255.254103.204.255.25565,534
206103.205.0.0/16103.205.0.1 to 103.205.255.254103.205.255.25565,534
207103.206.0.0/16103.206.0.1 to 103.206.255.254103.206.255.25565,534
208103.207.0.0/16103.207.0.1 to 103.207.255.254103.207.255.25565,534
209103.208.0.0/16103.208.0.1 to 103.208.255.254103.208.255.25565,534
210103.209.0.0/16103.209.0.1 to 103.209.255.254103.209.255.25565,534
211103.210.0.0/16103.210.0.1 to 103.210.255.254103.210.255.25565,534
212103.211.0.0/16103.211.0.1 to 103.211.255.254103.211.255.25565,534
213103.212.0.0/16103.212.0.1 to 103.212.255.254103.212.255.25565,534
214103.213.0.0/16103.213.0.1 to 103.213.255.254103.213.255.25565,534
215103.214.0.0/16103.214.0.1 to 103.214.255.254103.214.255.25565,534
216103.215.0.0/16103.215.0.1 to 103.215.255.254103.215.255.25565,534
217103.216.0.0/16103.216.0.1 to 103.216.255.254103.216.255.25565,534
218103.217.0.0/16103.217.0.1 to 103.217.255.254103.217.255.25565,534
219103.218.0.0/16103.218.0.1 to 103.218.255.254103.218.255.25565,534
220103.219.0.0/16103.219.0.1 to 103.219.255.254103.219.255.25565,534
221103.220.0.0/16103.220.0.1 to 103.220.255.254103.220.255.25565,534
222103.221.0.0/16103.221.0.1 to 103.221.255.254103.221.255.25565,534
223103.222.0.0/16103.222.0.1 to 103.222.255.254103.222.255.25565,534
224103.223.0.0/16103.223.0.1 to 103.223.255.254103.223.255.25565,534
225103.224.0.0/16103.224.0.1 to 103.224.255.254103.224.255.25565,534
226103.225.0.0/16103.225.0.1 to 103.225.255.254103.225.255.25565,534
227103.226.0.0/16103.226.0.1 to 103.226.255.254103.226.255.25565,534
228103.227.0.0/16103.227.0.1 to 103.227.255.254103.227.255.25565,534
229103.228.0.0/16103.228.0.1 to 103.228.255.254103.228.255.25565,534
230103.229.0.0/16103.229.0.1 to 103.229.255.254103.229.255.25565,534
231103.230.0.0/16103.230.0.1 to 103.230.255.254103.230.255.25565,534
232103.231.0.0/16103.231.0.1 to 103.231.255.254103.231.255.25565,534
233103.232.0.0/16103.232.0.1 to 103.232.255.254103.232.255.25565,534
234103.233.0.0/16103.233.0.1 to 103.233.255.254103.233.255.25565,534
235103.234.0.0/16103.234.0.1 to 103.234.255.254103.234.255.25565,534
236103.235.0.0/16103.235.0.1 to 103.235.255.254103.235.255.25565,534
237103.236.0.0/16103.236.0.1 to 103.236.255.254103.236.255.25565,534
238103.237.0.0/16103.237.0.1 to 103.237.255.254103.237.255.25565,534
239103.238.0.0/16103.238.0.1 to 103.238.255.254103.238.255.25565,534
240103.239.0.0/16103.239.0.1 to 103.239.255.254103.239.255.25565,534
241103.240.0.0/16103.240.0.1 to 103.240.255.254103.240.255.25565,534
242103.241.0.0/16103.241.0.1 to 103.241.255.254103.241.255.25565,534
243103.242.0.0/16103.242.0.1 to 103.242.255.254103.242.255.25565,534
244103.243.0.0/16103.243.0.1 to 103.243.255.254103.243.255.25565,534
245103.244.0.0/16103.244.0.1 to 103.244.255.254103.244.255.25565,534
246103.245.0.0/16103.245.0.1 to 103.245.255.254103.245.255.25565,534
247103.246.0.0/16103.246.0.1 to 103.246.255.254103.246.255.25565,534
248103.247.0.0/16103.247.0.1 to 103.247.255.254103.247.255.25565,534
249103.248.0.0/16103.248.0.1 to 103.248.255.254103.248.255.25565,534
250103.249.0.0/16103.249.0.1 to 103.249.255.254103.249.255.25565,534
251103.250.0.0/16103.250.0.1 to 103.250.255.254103.250.255.25565,534
252103.251.0.0/16103.251.0.1 to 103.251.255.254103.251.255.25565,534
253103.252.0.0/16103.252.0.1 to 103.252.255.254103.252.255.25565,534
254103.253.0.0/16103.253.0.1 to 103.253.255.254103.253.255.25565,534
255103.254.0.0/16103.254.0.1 to 103.254.255.254103.254.255.25565,534
256103.255.0.0/16103.255.0.1 to 103.255.255.254103.255.255.25565,534

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.