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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.

Network228.96.0.0/12
Usable hosts1,048,574
Subnet mask255.240.0.0
Addresses1,048,576
Network address
228.96.0.0
Broadcast address
228.111.255.255
First usable
228.96.0.1
Last usable
228.111.255.254
Usable hosts
1,048,574 (1,048,576 less the network and broadcast addresses)
Subnet mask
255.240.0.0
Wildcard mask
0.15.255.255 (Cisco ACLs, OSPF)
Prefix length
/12
Type
Multicast 224.0.0.0/4
One-to-many traffic, such as IPTV and routing protocols
Old class
D (multicast)
As numbers
Hex E4600000 · Integer 3831496704 to 3832545279
Reverse DNS zones
96.228.in-addr.arpa
97.228.in-addr.arpa
98.228.in-addr.arpa
99.228.in-addr.arpa
100.228.in-addr.arpa
101.228.in-addr.arpa
102.228.in-addr.arpa
103.228.in-addr.arpa
104.228.in-addr.arpa
105.228.in-addr.arpa
106.228.in-addr.arpa
107.228.in-addr.arpa
108.228.in-addr.arpa
109.228.in-addr.arpa
110.228.in-addr.arpa
111.228.in-addr.arpa
/12 is not on a 8-bit boundary, so it takes 16 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11100100.01100000.00000000.00000000228.96.0.0
Subnet mask11111111.11110000.00000000.00000000255.240.0.0
Network11100100.01100000.00000000.00000000228.96.0.0
Broadcast11100100.01101111.11111111.11111111228.111.255.255
Split into smaller subnets/21
/13 (2)/14 (4)/15 (8)/16 (16)/17 (32)/18 (64)/19 (128)/20 (256)/21 (512)/22 (1,024)/23 (2,048)/24 (4,096)

228.96.0.0/12 makes 512 subnets of /21; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1228.96.0.0/21228.96.0.1 to 228.96.7.254228.96.7.2552,046
2228.96.8.0/21228.96.8.1 to 228.96.15.254228.96.15.2552,046
3228.96.16.0/21228.96.16.1 to 228.96.23.254228.96.23.2552,046
4228.96.24.0/21228.96.24.1 to 228.96.31.254228.96.31.2552,046
5228.96.32.0/21228.96.32.1 to 228.96.39.254228.96.39.2552,046
6228.96.40.0/21228.96.40.1 to 228.96.47.254228.96.47.2552,046
7228.96.48.0/21228.96.48.1 to 228.96.55.254228.96.55.2552,046
8228.96.56.0/21228.96.56.1 to 228.96.63.254228.96.63.2552,046
9228.96.64.0/21228.96.64.1 to 228.96.71.254228.96.71.2552,046
10228.96.72.0/21228.96.72.1 to 228.96.79.254228.96.79.2552,046
11228.96.80.0/21228.96.80.1 to 228.96.87.254228.96.87.2552,046
12228.96.88.0/21228.96.88.1 to 228.96.95.254228.96.95.2552,046
13228.96.96.0/21228.96.96.1 to 228.96.103.254228.96.103.2552,046
14228.96.104.0/21228.96.104.1 to 228.96.111.254228.96.111.2552,046
15228.96.112.0/21228.96.112.1 to 228.96.119.254228.96.119.2552,046
16228.96.120.0/21228.96.120.1 to 228.96.127.254228.96.127.2552,046
17228.96.128.0/21228.96.128.1 to 228.96.135.254228.96.135.2552,046
18228.96.136.0/21228.96.136.1 to 228.96.143.254228.96.143.2552,046
19228.96.144.0/21228.96.144.1 to 228.96.151.254228.96.151.2552,046
20228.96.152.0/21228.96.152.1 to 228.96.159.254228.96.159.2552,046
21228.96.160.0/21228.96.160.1 to 228.96.167.254228.96.167.2552,046
22228.96.168.0/21228.96.168.1 to 228.96.175.254228.96.175.2552,046
23228.96.176.0/21228.96.176.1 to 228.96.183.254228.96.183.2552,046
24228.96.184.0/21228.96.184.1 to 228.96.191.254228.96.191.2552,046
25228.96.192.0/21228.96.192.1 to 228.96.199.254228.96.199.2552,046
26228.96.200.0/21228.96.200.1 to 228.96.207.254228.96.207.2552,046
27228.96.208.0/21228.96.208.1 to 228.96.215.254228.96.215.2552,046
28228.96.216.0/21228.96.216.1 to 228.96.223.254228.96.223.2552,046
29228.96.224.0/21228.96.224.1 to 228.96.231.254228.96.231.2552,046
30228.96.232.0/21228.96.232.1 to 228.96.239.254228.96.239.2552,046
31228.96.240.0/21228.96.240.1 to 228.96.247.254228.96.247.2552,046
32228.96.248.0/21228.96.248.1 to 228.96.255.254228.96.255.2552,046
33228.97.0.0/21228.97.0.1 to 228.97.7.254228.97.7.2552,046
34228.97.8.0/21228.97.8.1 to 228.97.15.254228.97.15.2552,046
35228.97.16.0/21228.97.16.1 to 228.97.23.254228.97.23.2552,046
36228.97.24.0/21228.97.24.1 to 228.97.31.254228.97.31.2552,046
37228.97.32.0/21228.97.32.1 to 228.97.39.254228.97.39.2552,046
38228.97.40.0/21228.97.40.1 to 228.97.47.254228.97.47.2552,046
39228.97.48.0/21228.97.48.1 to 228.97.55.254228.97.55.2552,046
40228.97.56.0/21228.97.56.1 to 228.97.63.254228.97.63.2552,046
41228.97.64.0/21228.97.64.1 to 228.97.71.254228.97.71.2552,046
42228.97.72.0/21228.97.72.1 to 228.97.79.254228.97.79.2552,046
43228.97.80.0/21228.97.80.1 to 228.97.87.254228.97.87.2552,046
44228.97.88.0/21228.97.88.1 to 228.97.95.254228.97.95.2552,046
45228.97.96.0/21228.97.96.1 to 228.97.103.254228.97.103.2552,046
46228.97.104.0/21228.97.104.1 to 228.97.111.254228.97.111.2552,046
47228.97.112.0/21228.97.112.1 to 228.97.119.254228.97.119.2552,046
48228.97.120.0/21228.97.120.1 to 228.97.127.254228.97.127.2552,046
49228.97.128.0/21228.97.128.1 to 228.97.135.254228.97.135.2552,046
50228.97.136.0/21228.97.136.1 to 228.97.143.254228.97.143.2552,046
51228.97.144.0/21228.97.144.1 to 228.97.151.254228.97.151.2552,046
52228.97.152.0/21228.97.152.1 to 228.97.159.254228.97.159.2552,046
53228.97.160.0/21228.97.160.1 to 228.97.167.254228.97.167.2552,046
54228.97.168.0/21228.97.168.1 to 228.97.175.254228.97.175.2552,046
55228.97.176.0/21228.97.176.1 to 228.97.183.254228.97.183.2552,046
56228.97.184.0/21228.97.184.1 to 228.97.191.254228.97.191.2552,046
57228.97.192.0/21228.97.192.1 to 228.97.199.254228.97.199.2552,046
58228.97.200.0/21228.97.200.1 to 228.97.207.254228.97.207.2552,046
59228.97.208.0/21228.97.208.1 to 228.97.215.254228.97.215.2552,046
60228.97.216.0/21228.97.216.1 to 228.97.223.254228.97.223.2552,046
61228.97.224.0/21228.97.224.1 to 228.97.231.254228.97.231.2552,046
62228.97.232.0/21228.97.232.1 to 228.97.239.254228.97.239.2552,046
63228.97.240.0/21228.97.240.1 to 228.97.247.254228.97.247.2552,046
64228.97.248.0/21228.97.248.1 to 228.97.255.254228.97.255.2552,046
65228.98.0.0/21228.98.0.1 to 228.98.7.254228.98.7.2552,046
66228.98.8.0/21228.98.8.1 to 228.98.15.254228.98.15.2552,046
67228.98.16.0/21228.98.16.1 to 228.98.23.254228.98.23.2552,046
68228.98.24.0/21228.98.24.1 to 228.98.31.254228.98.31.2552,046
69228.98.32.0/21228.98.32.1 to 228.98.39.254228.98.39.2552,046
70228.98.40.0/21228.98.40.1 to 228.98.47.254228.98.47.2552,046
71228.98.48.0/21228.98.48.1 to 228.98.55.254228.98.55.2552,046
72228.98.56.0/21228.98.56.1 to 228.98.63.254228.98.63.2552,046
73228.98.64.0/21228.98.64.1 to 228.98.71.254228.98.71.2552,046
74228.98.72.0/21228.98.72.1 to 228.98.79.254228.98.79.2552,046
75228.98.80.0/21228.98.80.1 to 228.98.87.254228.98.87.2552,046
76228.98.88.0/21228.98.88.1 to 228.98.95.254228.98.95.2552,046
77228.98.96.0/21228.98.96.1 to 228.98.103.254228.98.103.2552,046
78228.98.104.0/21228.98.104.1 to 228.98.111.254228.98.111.2552,046
79228.98.112.0/21228.98.112.1 to 228.98.119.254228.98.119.2552,046
80228.98.120.0/21228.98.120.1 to 228.98.127.254228.98.127.2552,046
81228.98.128.0/21228.98.128.1 to 228.98.135.254228.98.135.2552,046
82228.98.136.0/21228.98.136.1 to 228.98.143.254228.98.143.2552,046
83228.98.144.0/21228.98.144.1 to 228.98.151.254228.98.151.2552,046
84228.98.152.0/21228.98.152.1 to 228.98.159.254228.98.159.2552,046
85228.98.160.0/21228.98.160.1 to 228.98.167.254228.98.167.2552,046
86228.98.168.0/21228.98.168.1 to 228.98.175.254228.98.175.2552,046
87228.98.176.0/21228.98.176.1 to 228.98.183.254228.98.183.2552,046
88228.98.184.0/21228.98.184.1 to 228.98.191.254228.98.191.2552,046
89228.98.192.0/21228.98.192.1 to 228.98.199.254228.98.199.2552,046
90228.98.200.0/21228.98.200.1 to 228.98.207.254228.98.207.2552,046
91228.98.208.0/21228.98.208.1 to 228.98.215.254228.98.215.2552,046
92228.98.216.0/21228.98.216.1 to 228.98.223.254228.98.223.2552,046
93228.98.224.0/21228.98.224.1 to 228.98.231.254228.98.231.2552,046
94228.98.232.0/21228.98.232.1 to 228.98.239.254228.98.239.2552,046
95228.98.240.0/21228.98.240.1 to 228.98.247.254228.98.247.2552,046
96228.98.248.0/21228.98.248.1 to 228.98.255.254228.98.255.2552,046
97228.99.0.0/21228.99.0.1 to 228.99.7.254228.99.7.2552,046
98228.99.8.0/21228.99.8.1 to 228.99.15.254228.99.15.2552,046
99228.99.16.0/21228.99.16.1 to 228.99.23.254228.99.23.2552,046
100228.99.24.0/21228.99.24.1 to 228.99.31.254228.99.31.2552,046
101228.99.32.0/21228.99.32.1 to 228.99.39.254228.99.39.2552,046
102228.99.40.0/21228.99.40.1 to 228.99.47.254228.99.47.2552,046
103228.99.48.0/21228.99.48.1 to 228.99.55.254228.99.55.2552,046
104228.99.56.0/21228.99.56.1 to 228.99.63.254228.99.63.2552,046
105228.99.64.0/21228.99.64.1 to 228.99.71.254228.99.71.2552,046
106228.99.72.0/21228.99.72.1 to 228.99.79.254228.99.79.2552,046
107228.99.80.0/21228.99.80.1 to 228.99.87.254228.99.87.2552,046
108228.99.88.0/21228.99.88.1 to 228.99.95.254228.99.95.2552,046
109228.99.96.0/21228.99.96.1 to 228.99.103.254228.99.103.2552,046
110228.99.104.0/21228.99.104.1 to 228.99.111.254228.99.111.2552,046
111228.99.112.0/21228.99.112.1 to 228.99.119.254228.99.119.2552,046
112228.99.120.0/21228.99.120.1 to 228.99.127.254228.99.127.2552,046
113228.99.128.0/21228.99.128.1 to 228.99.135.254228.99.135.2552,046
114228.99.136.0/21228.99.136.1 to 228.99.143.254228.99.143.2552,046
115228.99.144.0/21228.99.144.1 to 228.99.151.254228.99.151.2552,046
116228.99.152.0/21228.99.152.1 to 228.99.159.254228.99.159.2552,046
117228.99.160.0/21228.99.160.1 to 228.99.167.254228.99.167.2552,046
118228.99.168.0/21228.99.168.1 to 228.99.175.254228.99.175.2552,046
119228.99.176.0/21228.99.176.1 to 228.99.183.254228.99.183.2552,046
120228.99.184.0/21228.99.184.1 to 228.99.191.254228.99.191.2552,046
121228.99.192.0/21228.99.192.1 to 228.99.199.254228.99.199.2552,046
122228.99.200.0/21228.99.200.1 to 228.99.207.254228.99.207.2552,046
123228.99.208.0/21228.99.208.1 to 228.99.215.254228.99.215.2552,046
124228.99.216.0/21228.99.216.1 to 228.99.223.254228.99.223.2552,046
125228.99.224.0/21228.99.224.1 to 228.99.231.254228.99.231.2552,046
126228.99.232.0/21228.99.232.1 to 228.99.239.254228.99.239.2552,046
127228.99.240.0/21228.99.240.1 to 228.99.247.254228.99.247.2552,046
128228.99.248.0/21228.99.248.1 to 228.99.255.254228.99.255.2552,046
129228.100.0.0/21228.100.0.1 to 228.100.7.254228.100.7.2552,046
130228.100.8.0/21228.100.8.1 to 228.100.15.254228.100.15.2552,046
131228.100.16.0/21228.100.16.1 to 228.100.23.254228.100.23.2552,046
132228.100.24.0/21228.100.24.1 to 228.100.31.254228.100.31.2552,046
133228.100.32.0/21228.100.32.1 to 228.100.39.254228.100.39.2552,046
134228.100.40.0/21228.100.40.1 to 228.100.47.254228.100.47.2552,046
135228.100.48.0/21228.100.48.1 to 228.100.55.254228.100.55.2552,046
136228.100.56.0/21228.100.56.1 to 228.100.63.254228.100.63.2552,046
137228.100.64.0/21228.100.64.1 to 228.100.71.254228.100.71.2552,046
138228.100.72.0/21228.100.72.1 to 228.100.79.254228.100.79.2552,046
139228.100.80.0/21228.100.80.1 to 228.100.87.254228.100.87.2552,046
140228.100.88.0/21228.100.88.1 to 228.100.95.254228.100.95.2552,046
141228.100.96.0/21228.100.96.1 to 228.100.103.254228.100.103.2552,046
142228.100.104.0/21228.100.104.1 to 228.100.111.254228.100.111.2552,046
143228.100.112.0/21228.100.112.1 to 228.100.119.254228.100.119.2552,046
144228.100.120.0/21228.100.120.1 to 228.100.127.254228.100.127.2552,046
145228.100.128.0/21228.100.128.1 to 228.100.135.254228.100.135.2552,046
146228.100.136.0/21228.100.136.1 to 228.100.143.254228.100.143.2552,046
147228.100.144.0/21228.100.144.1 to 228.100.151.254228.100.151.2552,046
148228.100.152.0/21228.100.152.1 to 228.100.159.254228.100.159.2552,046
149228.100.160.0/21228.100.160.1 to 228.100.167.254228.100.167.2552,046
150228.100.168.0/21228.100.168.1 to 228.100.175.254228.100.175.2552,046
151228.100.176.0/21228.100.176.1 to 228.100.183.254228.100.183.2552,046
152228.100.184.0/21228.100.184.1 to 228.100.191.254228.100.191.2552,046
153228.100.192.0/21228.100.192.1 to 228.100.199.254228.100.199.2552,046
154228.100.200.0/21228.100.200.1 to 228.100.207.254228.100.207.2552,046
155228.100.208.0/21228.100.208.1 to 228.100.215.254228.100.215.2552,046
156228.100.216.0/21228.100.216.1 to 228.100.223.254228.100.223.2552,046
157228.100.224.0/21228.100.224.1 to 228.100.231.254228.100.231.2552,046
158228.100.232.0/21228.100.232.1 to 228.100.239.254228.100.239.2552,046
159228.100.240.0/21228.100.240.1 to 228.100.247.254228.100.247.2552,046
160228.100.248.0/21228.100.248.1 to 228.100.255.254228.100.255.2552,046
161228.101.0.0/21228.101.0.1 to 228.101.7.254228.101.7.2552,046
162228.101.8.0/21228.101.8.1 to 228.101.15.254228.101.15.2552,046
163228.101.16.0/21228.101.16.1 to 228.101.23.254228.101.23.2552,046
164228.101.24.0/21228.101.24.1 to 228.101.31.254228.101.31.2552,046
165228.101.32.0/21228.101.32.1 to 228.101.39.254228.101.39.2552,046
166228.101.40.0/21228.101.40.1 to 228.101.47.254228.101.47.2552,046
167228.101.48.0/21228.101.48.1 to 228.101.55.254228.101.55.2552,046
168228.101.56.0/21228.101.56.1 to 228.101.63.254228.101.63.2552,046
169228.101.64.0/21228.101.64.1 to 228.101.71.254228.101.71.2552,046
170228.101.72.0/21228.101.72.1 to 228.101.79.254228.101.79.2552,046
171228.101.80.0/21228.101.80.1 to 228.101.87.254228.101.87.2552,046
172228.101.88.0/21228.101.88.1 to 228.101.95.254228.101.95.2552,046
173228.101.96.0/21228.101.96.1 to 228.101.103.254228.101.103.2552,046
174228.101.104.0/21228.101.104.1 to 228.101.111.254228.101.111.2552,046
175228.101.112.0/21228.101.112.1 to 228.101.119.254228.101.119.2552,046
176228.101.120.0/21228.101.120.1 to 228.101.127.254228.101.127.2552,046
177228.101.128.0/21228.101.128.1 to 228.101.135.254228.101.135.2552,046
178228.101.136.0/21228.101.136.1 to 228.101.143.254228.101.143.2552,046
179228.101.144.0/21228.101.144.1 to 228.101.151.254228.101.151.2552,046
180228.101.152.0/21228.101.152.1 to 228.101.159.254228.101.159.2552,046
181228.101.160.0/21228.101.160.1 to 228.101.167.254228.101.167.2552,046
182228.101.168.0/21228.101.168.1 to 228.101.175.254228.101.175.2552,046
183228.101.176.0/21228.101.176.1 to 228.101.183.254228.101.183.2552,046
184228.101.184.0/21228.101.184.1 to 228.101.191.254228.101.191.2552,046
185228.101.192.0/21228.101.192.1 to 228.101.199.254228.101.199.2552,046
186228.101.200.0/21228.101.200.1 to 228.101.207.254228.101.207.2552,046
187228.101.208.0/21228.101.208.1 to 228.101.215.254228.101.215.2552,046
188228.101.216.0/21228.101.216.1 to 228.101.223.254228.101.223.2552,046
189228.101.224.0/21228.101.224.1 to 228.101.231.254228.101.231.2552,046
190228.101.232.0/21228.101.232.1 to 228.101.239.254228.101.239.2552,046
191228.101.240.0/21228.101.240.1 to 228.101.247.254228.101.247.2552,046
192228.101.248.0/21228.101.248.1 to 228.101.255.254228.101.255.2552,046
193228.102.0.0/21228.102.0.1 to 228.102.7.254228.102.7.2552,046
194228.102.8.0/21228.102.8.1 to 228.102.15.254228.102.15.2552,046
195228.102.16.0/21228.102.16.1 to 228.102.23.254228.102.23.2552,046
196228.102.24.0/21228.102.24.1 to 228.102.31.254228.102.31.2552,046
197228.102.32.0/21228.102.32.1 to 228.102.39.254228.102.39.2552,046
198228.102.40.0/21228.102.40.1 to 228.102.47.254228.102.47.2552,046
199228.102.48.0/21228.102.48.1 to 228.102.55.254228.102.55.2552,046
200228.102.56.0/21228.102.56.1 to 228.102.63.254228.102.63.2552,046
201228.102.64.0/21228.102.64.1 to 228.102.71.254228.102.71.2552,046
202228.102.72.0/21228.102.72.1 to 228.102.79.254228.102.79.2552,046
203228.102.80.0/21228.102.80.1 to 228.102.87.254228.102.87.2552,046
204228.102.88.0/21228.102.88.1 to 228.102.95.254228.102.95.2552,046
205228.102.96.0/21228.102.96.1 to 228.102.103.254228.102.103.2552,046
206228.102.104.0/21228.102.104.1 to 228.102.111.254228.102.111.2552,046
207228.102.112.0/21228.102.112.1 to 228.102.119.254228.102.119.2552,046
208228.102.120.0/21228.102.120.1 to 228.102.127.254228.102.127.2552,046
209228.102.128.0/21228.102.128.1 to 228.102.135.254228.102.135.2552,046
210228.102.136.0/21228.102.136.1 to 228.102.143.254228.102.143.2552,046
211228.102.144.0/21228.102.144.1 to 228.102.151.254228.102.151.2552,046
212228.102.152.0/21228.102.152.1 to 228.102.159.254228.102.159.2552,046
213228.102.160.0/21228.102.160.1 to 228.102.167.254228.102.167.2552,046
214228.102.168.0/21228.102.168.1 to 228.102.175.254228.102.175.2552,046
215228.102.176.0/21228.102.176.1 to 228.102.183.254228.102.183.2552,046
216228.102.184.0/21228.102.184.1 to 228.102.191.254228.102.191.2552,046
217228.102.192.0/21228.102.192.1 to 228.102.199.254228.102.199.2552,046
218228.102.200.0/21228.102.200.1 to 228.102.207.254228.102.207.2552,046
219228.102.208.0/21228.102.208.1 to 228.102.215.254228.102.215.2552,046
220228.102.216.0/21228.102.216.1 to 228.102.223.254228.102.223.2552,046
221228.102.224.0/21228.102.224.1 to 228.102.231.254228.102.231.2552,046
222228.102.232.0/21228.102.232.1 to 228.102.239.254228.102.239.2552,046
223228.102.240.0/21228.102.240.1 to 228.102.247.254228.102.247.2552,046
224228.102.248.0/21228.102.248.1 to 228.102.255.254228.102.255.2552,046
225228.103.0.0/21228.103.0.1 to 228.103.7.254228.103.7.2552,046
226228.103.8.0/21228.103.8.1 to 228.103.15.254228.103.15.2552,046
227228.103.16.0/21228.103.16.1 to 228.103.23.254228.103.23.2552,046
228228.103.24.0/21228.103.24.1 to 228.103.31.254228.103.31.2552,046
229228.103.32.0/21228.103.32.1 to 228.103.39.254228.103.39.2552,046
230228.103.40.0/21228.103.40.1 to 228.103.47.254228.103.47.2552,046
231228.103.48.0/21228.103.48.1 to 228.103.55.254228.103.55.2552,046
232228.103.56.0/21228.103.56.1 to 228.103.63.254228.103.63.2552,046
233228.103.64.0/21228.103.64.1 to 228.103.71.254228.103.71.2552,046
234228.103.72.0/21228.103.72.1 to 228.103.79.254228.103.79.2552,046
235228.103.80.0/21228.103.80.1 to 228.103.87.254228.103.87.2552,046
236228.103.88.0/21228.103.88.1 to 228.103.95.254228.103.95.2552,046
237228.103.96.0/21228.103.96.1 to 228.103.103.254228.103.103.2552,046
238228.103.104.0/21228.103.104.1 to 228.103.111.254228.103.111.2552,046
239228.103.112.0/21228.103.112.1 to 228.103.119.254228.103.119.2552,046
240228.103.120.0/21228.103.120.1 to 228.103.127.254228.103.127.2552,046
241228.103.128.0/21228.103.128.1 to 228.103.135.254228.103.135.2552,046
242228.103.136.0/21228.103.136.1 to 228.103.143.254228.103.143.2552,046
243228.103.144.0/21228.103.144.1 to 228.103.151.254228.103.151.2552,046
244228.103.152.0/21228.103.152.1 to 228.103.159.254228.103.159.2552,046
245228.103.160.0/21228.103.160.1 to 228.103.167.254228.103.167.2552,046
246228.103.168.0/21228.103.168.1 to 228.103.175.254228.103.175.2552,046
247228.103.176.0/21228.103.176.1 to 228.103.183.254228.103.183.2552,046
248228.103.184.0/21228.103.184.1 to 228.103.191.254228.103.191.2552,046
249228.103.192.0/21228.103.192.1 to 228.103.199.254228.103.199.2552,046
250228.103.200.0/21228.103.200.1 to 228.103.207.254228.103.207.2552,046
251228.103.208.0/21228.103.208.1 to 228.103.215.254228.103.215.2552,046
252228.103.216.0/21228.103.216.1 to 228.103.223.254228.103.223.2552,046
253228.103.224.0/21228.103.224.1 to 228.103.231.254228.103.231.2552,046
254228.103.232.0/21228.103.232.1 to 228.103.239.254228.103.239.2552,046
255228.103.240.0/21228.103.240.1 to 228.103.247.254228.103.247.2552,046
256228.103.248.0/21228.103.248.1 to 228.103.255.254228.103.255.2552,046

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.