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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.

Network253.80.0.0/12
Usable hosts1,048,574
Subnet mask255.240.0.0
Addresses1,048,576
Network address
253.80.0.0
Broadcast address
253.95.255.255
First usable
253.80.0.1
Last usable
253.95.255.254
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
Reserved 240.0.0.0/4
Future use; not usable on most systems
Old class
E (reserved)
As numbers
Hex FD500000 · Integer 4249878528 to 4250927103
Reverse DNS zones
80.253.in-addr.arpa
81.253.in-addr.arpa
82.253.in-addr.arpa
83.253.in-addr.arpa
84.253.in-addr.arpa
85.253.in-addr.arpa
86.253.in-addr.arpa
87.253.in-addr.arpa
88.253.in-addr.arpa
89.253.in-addr.arpa
90.253.in-addr.arpa
91.253.in-addr.arpa
92.253.in-addr.arpa
93.253.in-addr.arpa
94.253.in-addr.arpa
95.253.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
Address11111101.01010000.00000000.00000000253.80.0.0
Subnet mask11111111.11110000.00000000.00000000255.240.0.0
Network11111101.01010000.00000000.00000000253.80.0.0
Broadcast11111101.01011111.11111111.11111111253.95.255.255
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)

253.80.0.0/12 makes 512 subnets of /21; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1253.80.0.0/21253.80.0.1 to 253.80.7.254253.80.7.2552,046
2253.80.8.0/21253.80.8.1 to 253.80.15.254253.80.15.2552,046
3253.80.16.0/21253.80.16.1 to 253.80.23.254253.80.23.2552,046
4253.80.24.0/21253.80.24.1 to 253.80.31.254253.80.31.2552,046
5253.80.32.0/21253.80.32.1 to 253.80.39.254253.80.39.2552,046
6253.80.40.0/21253.80.40.1 to 253.80.47.254253.80.47.2552,046
7253.80.48.0/21253.80.48.1 to 253.80.55.254253.80.55.2552,046
8253.80.56.0/21253.80.56.1 to 253.80.63.254253.80.63.2552,046
9253.80.64.0/21253.80.64.1 to 253.80.71.254253.80.71.2552,046
10253.80.72.0/21253.80.72.1 to 253.80.79.254253.80.79.2552,046
11253.80.80.0/21253.80.80.1 to 253.80.87.254253.80.87.2552,046
12253.80.88.0/21253.80.88.1 to 253.80.95.254253.80.95.2552,046
13253.80.96.0/21253.80.96.1 to 253.80.103.254253.80.103.2552,046
14253.80.104.0/21253.80.104.1 to 253.80.111.254253.80.111.2552,046
15253.80.112.0/21253.80.112.1 to 253.80.119.254253.80.119.2552,046
16253.80.120.0/21253.80.120.1 to 253.80.127.254253.80.127.2552,046
17253.80.128.0/21253.80.128.1 to 253.80.135.254253.80.135.2552,046
18253.80.136.0/21253.80.136.1 to 253.80.143.254253.80.143.2552,046
19253.80.144.0/21253.80.144.1 to 253.80.151.254253.80.151.2552,046
20253.80.152.0/21253.80.152.1 to 253.80.159.254253.80.159.2552,046
21253.80.160.0/21253.80.160.1 to 253.80.167.254253.80.167.2552,046
22253.80.168.0/21253.80.168.1 to 253.80.175.254253.80.175.2552,046
23253.80.176.0/21253.80.176.1 to 253.80.183.254253.80.183.2552,046
24253.80.184.0/21253.80.184.1 to 253.80.191.254253.80.191.2552,046
25253.80.192.0/21253.80.192.1 to 253.80.199.254253.80.199.2552,046
26253.80.200.0/21253.80.200.1 to 253.80.207.254253.80.207.2552,046
27253.80.208.0/21253.80.208.1 to 253.80.215.254253.80.215.2552,046
28253.80.216.0/21253.80.216.1 to 253.80.223.254253.80.223.2552,046
29253.80.224.0/21253.80.224.1 to 253.80.231.254253.80.231.2552,046
30253.80.232.0/21253.80.232.1 to 253.80.239.254253.80.239.2552,046
31253.80.240.0/21253.80.240.1 to 253.80.247.254253.80.247.2552,046
32253.80.248.0/21253.80.248.1 to 253.80.255.254253.80.255.2552,046
33253.81.0.0/21253.81.0.1 to 253.81.7.254253.81.7.2552,046
34253.81.8.0/21253.81.8.1 to 253.81.15.254253.81.15.2552,046
35253.81.16.0/21253.81.16.1 to 253.81.23.254253.81.23.2552,046
36253.81.24.0/21253.81.24.1 to 253.81.31.254253.81.31.2552,046
37253.81.32.0/21253.81.32.1 to 253.81.39.254253.81.39.2552,046
38253.81.40.0/21253.81.40.1 to 253.81.47.254253.81.47.2552,046
39253.81.48.0/21253.81.48.1 to 253.81.55.254253.81.55.2552,046
40253.81.56.0/21253.81.56.1 to 253.81.63.254253.81.63.2552,046
41253.81.64.0/21253.81.64.1 to 253.81.71.254253.81.71.2552,046
42253.81.72.0/21253.81.72.1 to 253.81.79.254253.81.79.2552,046
43253.81.80.0/21253.81.80.1 to 253.81.87.254253.81.87.2552,046
44253.81.88.0/21253.81.88.1 to 253.81.95.254253.81.95.2552,046
45253.81.96.0/21253.81.96.1 to 253.81.103.254253.81.103.2552,046
46253.81.104.0/21253.81.104.1 to 253.81.111.254253.81.111.2552,046
47253.81.112.0/21253.81.112.1 to 253.81.119.254253.81.119.2552,046
48253.81.120.0/21253.81.120.1 to 253.81.127.254253.81.127.2552,046
49253.81.128.0/21253.81.128.1 to 253.81.135.254253.81.135.2552,046
50253.81.136.0/21253.81.136.1 to 253.81.143.254253.81.143.2552,046
51253.81.144.0/21253.81.144.1 to 253.81.151.254253.81.151.2552,046
52253.81.152.0/21253.81.152.1 to 253.81.159.254253.81.159.2552,046
53253.81.160.0/21253.81.160.1 to 253.81.167.254253.81.167.2552,046
54253.81.168.0/21253.81.168.1 to 253.81.175.254253.81.175.2552,046
55253.81.176.0/21253.81.176.1 to 253.81.183.254253.81.183.2552,046
56253.81.184.0/21253.81.184.1 to 253.81.191.254253.81.191.2552,046
57253.81.192.0/21253.81.192.1 to 253.81.199.254253.81.199.2552,046
58253.81.200.0/21253.81.200.1 to 253.81.207.254253.81.207.2552,046
59253.81.208.0/21253.81.208.1 to 253.81.215.254253.81.215.2552,046
60253.81.216.0/21253.81.216.1 to 253.81.223.254253.81.223.2552,046
61253.81.224.0/21253.81.224.1 to 253.81.231.254253.81.231.2552,046
62253.81.232.0/21253.81.232.1 to 253.81.239.254253.81.239.2552,046
63253.81.240.0/21253.81.240.1 to 253.81.247.254253.81.247.2552,046
64253.81.248.0/21253.81.248.1 to 253.81.255.254253.81.255.2552,046
65253.82.0.0/21253.82.0.1 to 253.82.7.254253.82.7.2552,046
66253.82.8.0/21253.82.8.1 to 253.82.15.254253.82.15.2552,046
67253.82.16.0/21253.82.16.1 to 253.82.23.254253.82.23.2552,046
68253.82.24.0/21253.82.24.1 to 253.82.31.254253.82.31.2552,046
69253.82.32.0/21253.82.32.1 to 253.82.39.254253.82.39.2552,046
70253.82.40.0/21253.82.40.1 to 253.82.47.254253.82.47.2552,046
71253.82.48.0/21253.82.48.1 to 253.82.55.254253.82.55.2552,046
72253.82.56.0/21253.82.56.1 to 253.82.63.254253.82.63.2552,046
73253.82.64.0/21253.82.64.1 to 253.82.71.254253.82.71.2552,046
74253.82.72.0/21253.82.72.1 to 253.82.79.254253.82.79.2552,046
75253.82.80.0/21253.82.80.1 to 253.82.87.254253.82.87.2552,046
76253.82.88.0/21253.82.88.1 to 253.82.95.254253.82.95.2552,046
77253.82.96.0/21253.82.96.1 to 253.82.103.254253.82.103.2552,046
78253.82.104.0/21253.82.104.1 to 253.82.111.254253.82.111.2552,046
79253.82.112.0/21253.82.112.1 to 253.82.119.254253.82.119.2552,046
80253.82.120.0/21253.82.120.1 to 253.82.127.254253.82.127.2552,046
81253.82.128.0/21253.82.128.1 to 253.82.135.254253.82.135.2552,046
82253.82.136.0/21253.82.136.1 to 253.82.143.254253.82.143.2552,046
83253.82.144.0/21253.82.144.1 to 253.82.151.254253.82.151.2552,046
84253.82.152.0/21253.82.152.1 to 253.82.159.254253.82.159.2552,046
85253.82.160.0/21253.82.160.1 to 253.82.167.254253.82.167.2552,046
86253.82.168.0/21253.82.168.1 to 253.82.175.254253.82.175.2552,046
87253.82.176.0/21253.82.176.1 to 253.82.183.254253.82.183.2552,046
88253.82.184.0/21253.82.184.1 to 253.82.191.254253.82.191.2552,046
89253.82.192.0/21253.82.192.1 to 253.82.199.254253.82.199.2552,046
90253.82.200.0/21253.82.200.1 to 253.82.207.254253.82.207.2552,046
91253.82.208.0/21253.82.208.1 to 253.82.215.254253.82.215.2552,046
92253.82.216.0/21253.82.216.1 to 253.82.223.254253.82.223.2552,046
93253.82.224.0/21253.82.224.1 to 253.82.231.254253.82.231.2552,046
94253.82.232.0/21253.82.232.1 to 253.82.239.254253.82.239.2552,046
95253.82.240.0/21253.82.240.1 to 253.82.247.254253.82.247.2552,046
96253.82.248.0/21253.82.248.1 to 253.82.255.254253.82.255.2552,046
97253.83.0.0/21253.83.0.1 to 253.83.7.254253.83.7.2552,046
98253.83.8.0/21253.83.8.1 to 253.83.15.254253.83.15.2552,046
99253.83.16.0/21253.83.16.1 to 253.83.23.254253.83.23.2552,046
100253.83.24.0/21253.83.24.1 to 253.83.31.254253.83.31.2552,046
101253.83.32.0/21253.83.32.1 to 253.83.39.254253.83.39.2552,046
102253.83.40.0/21253.83.40.1 to 253.83.47.254253.83.47.2552,046
103253.83.48.0/21253.83.48.1 to 253.83.55.254253.83.55.2552,046
104253.83.56.0/21253.83.56.1 to 253.83.63.254253.83.63.2552,046
105253.83.64.0/21253.83.64.1 to 253.83.71.254253.83.71.2552,046
106253.83.72.0/21253.83.72.1 to 253.83.79.254253.83.79.2552,046
107253.83.80.0/21253.83.80.1 to 253.83.87.254253.83.87.2552,046
108253.83.88.0/21253.83.88.1 to 253.83.95.254253.83.95.2552,046
109253.83.96.0/21253.83.96.1 to 253.83.103.254253.83.103.2552,046
110253.83.104.0/21253.83.104.1 to 253.83.111.254253.83.111.2552,046
111253.83.112.0/21253.83.112.1 to 253.83.119.254253.83.119.2552,046
112253.83.120.0/21253.83.120.1 to 253.83.127.254253.83.127.2552,046
113253.83.128.0/21253.83.128.1 to 253.83.135.254253.83.135.2552,046
114253.83.136.0/21253.83.136.1 to 253.83.143.254253.83.143.2552,046
115253.83.144.0/21253.83.144.1 to 253.83.151.254253.83.151.2552,046
116253.83.152.0/21253.83.152.1 to 253.83.159.254253.83.159.2552,046
117253.83.160.0/21253.83.160.1 to 253.83.167.254253.83.167.2552,046
118253.83.168.0/21253.83.168.1 to 253.83.175.254253.83.175.2552,046
119253.83.176.0/21253.83.176.1 to 253.83.183.254253.83.183.2552,046
120253.83.184.0/21253.83.184.1 to 253.83.191.254253.83.191.2552,046
121253.83.192.0/21253.83.192.1 to 253.83.199.254253.83.199.2552,046
122253.83.200.0/21253.83.200.1 to 253.83.207.254253.83.207.2552,046
123253.83.208.0/21253.83.208.1 to 253.83.215.254253.83.215.2552,046
124253.83.216.0/21253.83.216.1 to 253.83.223.254253.83.223.2552,046
125253.83.224.0/21253.83.224.1 to 253.83.231.254253.83.231.2552,046
126253.83.232.0/21253.83.232.1 to 253.83.239.254253.83.239.2552,046
127253.83.240.0/21253.83.240.1 to 253.83.247.254253.83.247.2552,046
128253.83.248.0/21253.83.248.1 to 253.83.255.254253.83.255.2552,046
129253.84.0.0/21253.84.0.1 to 253.84.7.254253.84.7.2552,046
130253.84.8.0/21253.84.8.1 to 253.84.15.254253.84.15.2552,046
131253.84.16.0/21253.84.16.1 to 253.84.23.254253.84.23.2552,046
132253.84.24.0/21253.84.24.1 to 253.84.31.254253.84.31.2552,046
133253.84.32.0/21253.84.32.1 to 253.84.39.254253.84.39.2552,046
134253.84.40.0/21253.84.40.1 to 253.84.47.254253.84.47.2552,046
135253.84.48.0/21253.84.48.1 to 253.84.55.254253.84.55.2552,046
136253.84.56.0/21253.84.56.1 to 253.84.63.254253.84.63.2552,046
137253.84.64.0/21253.84.64.1 to 253.84.71.254253.84.71.2552,046
138253.84.72.0/21253.84.72.1 to 253.84.79.254253.84.79.2552,046
139253.84.80.0/21253.84.80.1 to 253.84.87.254253.84.87.2552,046
140253.84.88.0/21253.84.88.1 to 253.84.95.254253.84.95.2552,046
141253.84.96.0/21253.84.96.1 to 253.84.103.254253.84.103.2552,046
142253.84.104.0/21253.84.104.1 to 253.84.111.254253.84.111.2552,046
143253.84.112.0/21253.84.112.1 to 253.84.119.254253.84.119.2552,046
144253.84.120.0/21253.84.120.1 to 253.84.127.254253.84.127.2552,046
145253.84.128.0/21253.84.128.1 to 253.84.135.254253.84.135.2552,046
146253.84.136.0/21253.84.136.1 to 253.84.143.254253.84.143.2552,046
147253.84.144.0/21253.84.144.1 to 253.84.151.254253.84.151.2552,046
148253.84.152.0/21253.84.152.1 to 253.84.159.254253.84.159.2552,046
149253.84.160.0/21253.84.160.1 to 253.84.167.254253.84.167.2552,046
150253.84.168.0/21253.84.168.1 to 253.84.175.254253.84.175.2552,046
151253.84.176.0/21253.84.176.1 to 253.84.183.254253.84.183.2552,046
152253.84.184.0/21253.84.184.1 to 253.84.191.254253.84.191.2552,046
153253.84.192.0/21253.84.192.1 to 253.84.199.254253.84.199.2552,046
154253.84.200.0/21253.84.200.1 to 253.84.207.254253.84.207.2552,046
155253.84.208.0/21253.84.208.1 to 253.84.215.254253.84.215.2552,046
156253.84.216.0/21253.84.216.1 to 253.84.223.254253.84.223.2552,046
157253.84.224.0/21253.84.224.1 to 253.84.231.254253.84.231.2552,046
158253.84.232.0/21253.84.232.1 to 253.84.239.254253.84.239.2552,046
159253.84.240.0/21253.84.240.1 to 253.84.247.254253.84.247.2552,046
160253.84.248.0/21253.84.248.1 to 253.84.255.254253.84.255.2552,046
161253.85.0.0/21253.85.0.1 to 253.85.7.254253.85.7.2552,046
162253.85.8.0/21253.85.8.1 to 253.85.15.254253.85.15.2552,046
163253.85.16.0/21253.85.16.1 to 253.85.23.254253.85.23.2552,046
164253.85.24.0/21253.85.24.1 to 253.85.31.254253.85.31.2552,046
165253.85.32.0/21253.85.32.1 to 253.85.39.254253.85.39.2552,046
166253.85.40.0/21253.85.40.1 to 253.85.47.254253.85.47.2552,046
167253.85.48.0/21253.85.48.1 to 253.85.55.254253.85.55.2552,046
168253.85.56.0/21253.85.56.1 to 253.85.63.254253.85.63.2552,046
169253.85.64.0/21253.85.64.1 to 253.85.71.254253.85.71.2552,046
170253.85.72.0/21253.85.72.1 to 253.85.79.254253.85.79.2552,046
171253.85.80.0/21253.85.80.1 to 253.85.87.254253.85.87.2552,046
172253.85.88.0/21253.85.88.1 to 253.85.95.254253.85.95.2552,046
173253.85.96.0/21253.85.96.1 to 253.85.103.254253.85.103.2552,046
174253.85.104.0/21253.85.104.1 to 253.85.111.254253.85.111.2552,046
175253.85.112.0/21253.85.112.1 to 253.85.119.254253.85.119.2552,046
176253.85.120.0/21253.85.120.1 to 253.85.127.254253.85.127.2552,046
177253.85.128.0/21253.85.128.1 to 253.85.135.254253.85.135.2552,046
178253.85.136.0/21253.85.136.1 to 253.85.143.254253.85.143.2552,046
179253.85.144.0/21253.85.144.1 to 253.85.151.254253.85.151.2552,046
180253.85.152.0/21253.85.152.1 to 253.85.159.254253.85.159.2552,046
181253.85.160.0/21253.85.160.1 to 253.85.167.254253.85.167.2552,046
182253.85.168.0/21253.85.168.1 to 253.85.175.254253.85.175.2552,046
183253.85.176.0/21253.85.176.1 to 253.85.183.254253.85.183.2552,046
184253.85.184.0/21253.85.184.1 to 253.85.191.254253.85.191.2552,046
185253.85.192.0/21253.85.192.1 to 253.85.199.254253.85.199.2552,046
186253.85.200.0/21253.85.200.1 to 253.85.207.254253.85.207.2552,046
187253.85.208.0/21253.85.208.1 to 253.85.215.254253.85.215.2552,046
188253.85.216.0/21253.85.216.1 to 253.85.223.254253.85.223.2552,046
189253.85.224.0/21253.85.224.1 to 253.85.231.254253.85.231.2552,046
190253.85.232.0/21253.85.232.1 to 253.85.239.254253.85.239.2552,046
191253.85.240.0/21253.85.240.1 to 253.85.247.254253.85.247.2552,046
192253.85.248.0/21253.85.248.1 to 253.85.255.254253.85.255.2552,046
193253.86.0.0/21253.86.0.1 to 253.86.7.254253.86.7.2552,046
194253.86.8.0/21253.86.8.1 to 253.86.15.254253.86.15.2552,046
195253.86.16.0/21253.86.16.1 to 253.86.23.254253.86.23.2552,046
196253.86.24.0/21253.86.24.1 to 253.86.31.254253.86.31.2552,046
197253.86.32.0/21253.86.32.1 to 253.86.39.254253.86.39.2552,046
198253.86.40.0/21253.86.40.1 to 253.86.47.254253.86.47.2552,046
199253.86.48.0/21253.86.48.1 to 253.86.55.254253.86.55.2552,046
200253.86.56.0/21253.86.56.1 to 253.86.63.254253.86.63.2552,046
201253.86.64.0/21253.86.64.1 to 253.86.71.254253.86.71.2552,046
202253.86.72.0/21253.86.72.1 to 253.86.79.254253.86.79.2552,046
203253.86.80.0/21253.86.80.1 to 253.86.87.254253.86.87.2552,046
204253.86.88.0/21253.86.88.1 to 253.86.95.254253.86.95.2552,046
205253.86.96.0/21253.86.96.1 to 253.86.103.254253.86.103.2552,046
206253.86.104.0/21253.86.104.1 to 253.86.111.254253.86.111.2552,046
207253.86.112.0/21253.86.112.1 to 253.86.119.254253.86.119.2552,046
208253.86.120.0/21253.86.120.1 to 253.86.127.254253.86.127.2552,046
209253.86.128.0/21253.86.128.1 to 253.86.135.254253.86.135.2552,046
210253.86.136.0/21253.86.136.1 to 253.86.143.254253.86.143.2552,046
211253.86.144.0/21253.86.144.1 to 253.86.151.254253.86.151.2552,046
212253.86.152.0/21253.86.152.1 to 253.86.159.254253.86.159.2552,046
213253.86.160.0/21253.86.160.1 to 253.86.167.254253.86.167.2552,046
214253.86.168.0/21253.86.168.1 to 253.86.175.254253.86.175.2552,046
215253.86.176.0/21253.86.176.1 to 253.86.183.254253.86.183.2552,046
216253.86.184.0/21253.86.184.1 to 253.86.191.254253.86.191.2552,046
217253.86.192.0/21253.86.192.1 to 253.86.199.254253.86.199.2552,046
218253.86.200.0/21253.86.200.1 to 253.86.207.254253.86.207.2552,046
219253.86.208.0/21253.86.208.1 to 253.86.215.254253.86.215.2552,046
220253.86.216.0/21253.86.216.1 to 253.86.223.254253.86.223.2552,046
221253.86.224.0/21253.86.224.1 to 253.86.231.254253.86.231.2552,046
222253.86.232.0/21253.86.232.1 to 253.86.239.254253.86.239.2552,046
223253.86.240.0/21253.86.240.1 to 253.86.247.254253.86.247.2552,046
224253.86.248.0/21253.86.248.1 to 253.86.255.254253.86.255.2552,046
225253.87.0.0/21253.87.0.1 to 253.87.7.254253.87.7.2552,046
226253.87.8.0/21253.87.8.1 to 253.87.15.254253.87.15.2552,046
227253.87.16.0/21253.87.16.1 to 253.87.23.254253.87.23.2552,046
228253.87.24.0/21253.87.24.1 to 253.87.31.254253.87.31.2552,046
229253.87.32.0/21253.87.32.1 to 253.87.39.254253.87.39.2552,046
230253.87.40.0/21253.87.40.1 to 253.87.47.254253.87.47.2552,046
231253.87.48.0/21253.87.48.1 to 253.87.55.254253.87.55.2552,046
232253.87.56.0/21253.87.56.1 to 253.87.63.254253.87.63.2552,046
233253.87.64.0/21253.87.64.1 to 253.87.71.254253.87.71.2552,046
234253.87.72.0/21253.87.72.1 to 253.87.79.254253.87.79.2552,046
235253.87.80.0/21253.87.80.1 to 253.87.87.254253.87.87.2552,046
236253.87.88.0/21253.87.88.1 to 253.87.95.254253.87.95.2552,046
237253.87.96.0/21253.87.96.1 to 253.87.103.254253.87.103.2552,046
238253.87.104.0/21253.87.104.1 to 253.87.111.254253.87.111.2552,046
239253.87.112.0/21253.87.112.1 to 253.87.119.254253.87.119.2552,046
240253.87.120.0/21253.87.120.1 to 253.87.127.254253.87.127.2552,046
241253.87.128.0/21253.87.128.1 to 253.87.135.254253.87.135.2552,046
242253.87.136.0/21253.87.136.1 to 253.87.143.254253.87.143.2552,046
243253.87.144.0/21253.87.144.1 to 253.87.151.254253.87.151.2552,046
244253.87.152.0/21253.87.152.1 to 253.87.159.254253.87.159.2552,046
245253.87.160.0/21253.87.160.1 to 253.87.167.254253.87.167.2552,046
246253.87.168.0/21253.87.168.1 to 253.87.175.254253.87.175.2552,046
247253.87.176.0/21253.87.176.1 to 253.87.183.254253.87.183.2552,046
248253.87.184.0/21253.87.184.1 to 253.87.191.254253.87.191.2552,046
249253.87.192.0/21253.87.192.1 to 253.87.199.254253.87.199.2552,046
250253.87.200.0/21253.87.200.1 to 253.87.207.254253.87.207.2552,046
251253.87.208.0/21253.87.208.1 to 253.87.215.254253.87.215.2552,046
252253.87.216.0/21253.87.216.1 to 253.87.223.254253.87.223.2552,046
253253.87.224.0/21253.87.224.1 to 253.87.231.254253.87.231.2552,046
254253.87.232.0/21253.87.232.1 to 253.87.239.254253.87.239.2552,046
255253.87.240.0/21253.87.240.1 to 253.87.247.254253.87.247.2552,046
256253.87.248.0/21253.87.248.1 to 253.87.255.254253.87.255.2552,046

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.