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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.

Network248.0.0.0/5
Usable hosts134,217,726
Subnet mask248.0.0.0
Addresses134,217,728
Network address
248.0.0.0
Broadcast address
255.255.255.255
First usable
248.0.0.1
Last usable
255.255.255.254
Usable hosts
134,217,726 (134,217,728 less the network and broadcast addresses)
Subnet mask
248.0.0.0
Wildcard mask
7.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/5
Type
Reserved 240.0.0.0/4
Future use; not usable on most systems
Old class
E (reserved)
As numbers
Hex F8000000 · Integer 4160749568 to 4294967295
Reverse DNS zones
248.in-addr.arpa
249.in-addr.arpa
250.in-addr.arpa
251.in-addr.arpa
252.in-addr.arpa
253.in-addr.arpa
254.in-addr.arpa
255.in-addr.arpa
/5 is not on a 8-bit boundary, so it takes 8 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11111000.00000000.00000000.00000000248.0.0.0
Subnet mask11111000.00000000.00000000.00000000248.0.0.0
Network11111000.00000000.00000000.00000000248.0.0.0
Broadcast11111111.11111111.11111111.11111111255.255.255.255
Split into smaller subnets/13
/6 (2)/7 (4)/8 (8)/9 (16)/10 (32)/11 (64)/12 (128)/13 (256)/14 (512)/15 (1,024)/16 (2,048)/17 (4,096)

248.0.0.0/5 makes 256 subnets of /13.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1248.0.0.0/13248.0.0.1 to 248.7.255.254248.7.255.255524,286
2248.8.0.0/13248.8.0.1 to 248.15.255.254248.15.255.255524,286
3248.16.0.0/13248.16.0.1 to 248.23.255.254248.23.255.255524,286
4248.24.0.0/13248.24.0.1 to 248.31.255.254248.31.255.255524,286
5248.32.0.0/13248.32.0.1 to 248.39.255.254248.39.255.255524,286
6248.40.0.0/13248.40.0.1 to 248.47.255.254248.47.255.255524,286
7248.48.0.0/13248.48.0.1 to 248.55.255.254248.55.255.255524,286
8248.56.0.0/13248.56.0.1 to 248.63.255.254248.63.255.255524,286
9248.64.0.0/13248.64.0.1 to 248.71.255.254248.71.255.255524,286
10248.72.0.0/13248.72.0.1 to 248.79.255.254248.79.255.255524,286
11248.80.0.0/13248.80.0.1 to 248.87.255.254248.87.255.255524,286
12248.88.0.0/13248.88.0.1 to 248.95.255.254248.95.255.255524,286
13248.96.0.0/13248.96.0.1 to 248.103.255.254248.103.255.255524,286
14248.104.0.0/13248.104.0.1 to 248.111.255.254248.111.255.255524,286
15248.112.0.0/13248.112.0.1 to 248.119.255.254248.119.255.255524,286
16248.120.0.0/13248.120.0.1 to 248.127.255.254248.127.255.255524,286
17248.128.0.0/13248.128.0.1 to 248.135.255.254248.135.255.255524,286
18248.136.0.0/13248.136.0.1 to 248.143.255.254248.143.255.255524,286
19248.144.0.0/13248.144.0.1 to 248.151.255.254248.151.255.255524,286
20248.152.0.0/13248.152.0.1 to 248.159.255.254248.159.255.255524,286
21248.160.0.0/13248.160.0.1 to 248.167.255.254248.167.255.255524,286
22248.168.0.0/13248.168.0.1 to 248.175.255.254248.175.255.255524,286
23248.176.0.0/13248.176.0.1 to 248.183.255.254248.183.255.255524,286
24248.184.0.0/13248.184.0.1 to 248.191.255.254248.191.255.255524,286
25248.192.0.0/13248.192.0.1 to 248.199.255.254248.199.255.255524,286
26248.200.0.0/13248.200.0.1 to 248.207.255.254248.207.255.255524,286
27248.208.0.0/13248.208.0.1 to 248.215.255.254248.215.255.255524,286
28248.216.0.0/13248.216.0.1 to 248.223.255.254248.223.255.255524,286
29248.224.0.0/13248.224.0.1 to 248.231.255.254248.231.255.255524,286
30248.232.0.0/13248.232.0.1 to 248.239.255.254248.239.255.255524,286
31248.240.0.0/13248.240.0.1 to 248.247.255.254248.247.255.255524,286
32248.248.0.0/13248.248.0.1 to 248.255.255.254248.255.255.255524,286
33249.0.0.0/13249.0.0.1 to 249.7.255.254249.7.255.255524,286
34249.8.0.0/13249.8.0.1 to 249.15.255.254249.15.255.255524,286
35249.16.0.0/13249.16.0.1 to 249.23.255.254249.23.255.255524,286
36249.24.0.0/13249.24.0.1 to 249.31.255.254249.31.255.255524,286
37249.32.0.0/13249.32.0.1 to 249.39.255.254249.39.255.255524,286
38249.40.0.0/13249.40.0.1 to 249.47.255.254249.47.255.255524,286
39249.48.0.0/13249.48.0.1 to 249.55.255.254249.55.255.255524,286
40249.56.0.0/13249.56.0.1 to 249.63.255.254249.63.255.255524,286
41249.64.0.0/13249.64.0.1 to 249.71.255.254249.71.255.255524,286
42249.72.0.0/13249.72.0.1 to 249.79.255.254249.79.255.255524,286
43249.80.0.0/13249.80.0.1 to 249.87.255.254249.87.255.255524,286
44249.88.0.0/13249.88.0.1 to 249.95.255.254249.95.255.255524,286
45249.96.0.0/13249.96.0.1 to 249.103.255.254249.103.255.255524,286
46249.104.0.0/13249.104.0.1 to 249.111.255.254249.111.255.255524,286
47249.112.0.0/13249.112.0.1 to 249.119.255.254249.119.255.255524,286
48249.120.0.0/13249.120.0.1 to 249.127.255.254249.127.255.255524,286
49249.128.0.0/13249.128.0.1 to 249.135.255.254249.135.255.255524,286
50249.136.0.0/13249.136.0.1 to 249.143.255.254249.143.255.255524,286
51249.144.0.0/13249.144.0.1 to 249.151.255.254249.151.255.255524,286
52249.152.0.0/13249.152.0.1 to 249.159.255.254249.159.255.255524,286
53249.160.0.0/13249.160.0.1 to 249.167.255.254249.167.255.255524,286
54249.168.0.0/13249.168.0.1 to 249.175.255.254249.175.255.255524,286
55249.176.0.0/13249.176.0.1 to 249.183.255.254249.183.255.255524,286
56249.184.0.0/13249.184.0.1 to 249.191.255.254249.191.255.255524,286
57249.192.0.0/13249.192.0.1 to 249.199.255.254249.199.255.255524,286
58249.200.0.0/13249.200.0.1 to 249.207.255.254249.207.255.255524,286
59249.208.0.0/13249.208.0.1 to 249.215.255.254249.215.255.255524,286
60249.216.0.0/13249.216.0.1 to 249.223.255.254249.223.255.255524,286
61249.224.0.0/13249.224.0.1 to 249.231.255.254249.231.255.255524,286
62249.232.0.0/13249.232.0.1 to 249.239.255.254249.239.255.255524,286
63249.240.0.0/13249.240.0.1 to 249.247.255.254249.247.255.255524,286
64249.248.0.0/13249.248.0.1 to 249.255.255.254249.255.255.255524,286
65250.0.0.0/13250.0.0.1 to 250.7.255.254250.7.255.255524,286
66250.8.0.0/13250.8.0.1 to 250.15.255.254250.15.255.255524,286
67250.16.0.0/13250.16.0.1 to 250.23.255.254250.23.255.255524,286
68250.24.0.0/13250.24.0.1 to 250.31.255.254250.31.255.255524,286
69250.32.0.0/13250.32.0.1 to 250.39.255.254250.39.255.255524,286
70250.40.0.0/13250.40.0.1 to 250.47.255.254250.47.255.255524,286
71250.48.0.0/13250.48.0.1 to 250.55.255.254250.55.255.255524,286
72250.56.0.0/13250.56.0.1 to 250.63.255.254250.63.255.255524,286
73250.64.0.0/13250.64.0.1 to 250.71.255.254250.71.255.255524,286
74250.72.0.0/13250.72.0.1 to 250.79.255.254250.79.255.255524,286
75250.80.0.0/13250.80.0.1 to 250.87.255.254250.87.255.255524,286
76250.88.0.0/13250.88.0.1 to 250.95.255.254250.95.255.255524,286
77250.96.0.0/13250.96.0.1 to 250.103.255.254250.103.255.255524,286
78250.104.0.0/13250.104.0.1 to 250.111.255.254250.111.255.255524,286
79250.112.0.0/13250.112.0.1 to 250.119.255.254250.119.255.255524,286
80250.120.0.0/13250.120.0.1 to 250.127.255.254250.127.255.255524,286
81250.128.0.0/13250.128.0.1 to 250.135.255.254250.135.255.255524,286
82250.136.0.0/13250.136.0.1 to 250.143.255.254250.143.255.255524,286
83250.144.0.0/13250.144.0.1 to 250.151.255.254250.151.255.255524,286
84250.152.0.0/13250.152.0.1 to 250.159.255.254250.159.255.255524,286
85250.160.0.0/13250.160.0.1 to 250.167.255.254250.167.255.255524,286
86250.168.0.0/13250.168.0.1 to 250.175.255.254250.175.255.255524,286
87250.176.0.0/13250.176.0.1 to 250.183.255.254250.183.255.255524,286
88250.184.0.0/13250.184.0.1 to 250.191.255.254250.191.255.255524,286
89250.192.0.0/13250.192.0.1 to 250.199.255.254250.199.255.255524,286
90250.200.0.0/13250.200.0.1 to 250.207.255.254250.207.255.255524,286
91250.208.0.0/13250.208.0.1 to 250.215.255.254250.215.255.255524,286
92250.216.0.0/13250.216.0.1 to 250.223.255.254250.223.255.255524,286
93250.224.0.0/13250.224.0.1 to 250.231.255.254250.231.255.255524,286
94250.232.0.0/13250.232.0.1 to 250.239.255.254250.239.255.255524,286
95250.240.0.0/13250.240.0.1 to 250.247.255.254250.247.255.255524,286
96250.248.0.0/13250.248.0.1 to 250.255.255.254250.255.255.255524,286
97251.0.0.0/13251.0.0.1 to 251.7.255.254251.7.255.255524,286
98251.8.0.0/13251.8.0.1 to 251.15.255.254251.15.255.255524,286
99251.16.0.0/13251.16.0.1 to 251.23.255.254251.23.255.255524,286
100251.24.0.0/13251.24.0.1 to 251.31.255.254251.31.255.255524,286
101251.32.0.0/13251.32.0.1 to 251.39.255.254251.39.255.255524,286
102251.40.0.0/13251.40.0.1 to 251.47.255.254251.47.255.255524,286
103251.48.0.0/13251.48.0.1 to 251.55.255.254251.55.255.255524,286
104251.56.0.0/13251.56.0.1 to 251.63.255.254251.63.255.255524,286
105251.64.0.0/13251.64.0.1 to 251.71.255.254251.71.255.255524,286
106251.72.0.0/13251.72.0.1 to 251.79.255.254251.79.255.255524,286
107251.80.0.0/13251.80.0.1 to 251.87.255.254251.87.255.255524,286
108251.88.0.0/13251.88.0.1 to 251.95.255.254251.95.255.255524,286
109251.96.0.0/13251.96.0.1 to 251.103.255.254251.103.255.255524,286
110251.104.0.0/13251.104.0.1 to 251.111.255.254251.111.255.255524,286
111251.112.0.0/13251.112.0.1 to 251.119.255.254251.119.255.255524,286
112251.120.0.0/13251.120.0.1 to 251.127.255.254251.127.255.255524,286
113251.128.0.0/13251.128.0.1 to 251.135.255.254251.135.255.255524,286
114251.136.0.0/13251.136.0.1 to 251.143.255.254251.143.255.255524,286
115251.144.0.0/13251.144.0.1 to 251.151.255.254251.151.255.255524,286
116251.152.0.0/13251.152.0.1 to 251.159.255.254251.159.255.255524,286
117251.160.0.0/13251.160.0.1 to 251.167.255.254251.167.255.255524,286
118251.168.0.0/13251.168.0.1 to 251.175.255.254251.175.255.255524,286
119251.176.0.0/13251.176.0.1 to 251.183.255.254251.183.255.255524,286
120251.184.0.0/13251.184.0.1 to 251.191.255.254251.191.255.255524,286
121251.192.0.0/13251.192.0.1 to 251.199.255.254251.199.255.255524,286
122251.200.0.0/13251.200.0.1 to 251.207.255.254251.207.255.255524,286
123251.208.0.0/13251.208.0.1 to 251.215.255.254251.215.255.255524,286
124251.216.0.0/13251.216.0.1 to 251.223.255.254251.223.255.255524,286
125251.224.0.0/13251.224.0.1 to 251.231.255.254251.231.255.255524,286
126251.232.0.0/13251.232.0.1 to 251.239.255.254251.239.255.255524,286
127251.240.0.0/13251.240.0.1 to 251.247.255.254251.247.255.255524,286
128251.248.0.0/13251.248.0.1 to 251.255.255.254251.255.255.255524,286
129252.0.0.0/13252.0.0.1 to 252.7.255.254252.7.255.255524,286
130252.8.0.0/13252.8.0.1 to 252.15.255.254252.15.255.255524,286
131252.16.0.0/13252.16.0.1 to 252.23.255.254252.23.255.255524,286
132252.24.0.0/13252.24.0.1 to 252.31.255.254252.31.255.255524,286
133252.32.0.0/13252.32.0.1 to 252.39.255.254252.39.255.255524,286
134252.40.0.0/13252.40.0.1 to 252.47.255.254252.47.255.255524,286
135252.48.0.0/13252.48.0.1 to 252.55.255.254252.55.255.255524,286
136252.56.0.0/13252.56.0.1 to 252.63.255.254252.63.255.255524,286
137252.64.0.0/13252.64.0.1 to 252.71.255.254252.71.255.255524,286
138252.72.0.0/13252.72.0.1 to 252.79.255.254252.79.255.255524,286
139252.80.0.0/13252.80.0.1 to 252.87.255.254252.87.255.255524,286
140252.88.0.0/13252.88.0.1 to 252.95.255.254252.95.255.255524,286
141252.96.0.0/13252.96.0.1 to 252.103.255.254252.103.255.255524,286
142252.104.0.0/13252.104.0.1 to 252.111.255.254252.111.255.255524,286
143252.112.0.0/13252.112.0.1 to 252.119.255.254252.119.255.255524,286
144252.120.0.0/13252.120.0.1 to 252.127.255.254252.127.255.255524,286
145252.128.0.0/13252.128.0.1 to 252.135.255.254252.135.255.255524,286
146252.136.0.0/13252.136.0.1 to 252.143.255.254252.143.255.255524,286
147252.144.0.0/13252.144.0.1 to 252.151.255.254252.151.255.255524,286
148252.152.0.0/13252.152.0.1 to 252.159.255.254252.159.255.255524,286
149252.160.0.0/13252.160.0.1 to 252.167.255.254252.167.255.255524,286
150252.168.0.0/13252.168.0.1 to 252.175.255.254252.175.255.255524,286
151252.176.0.0/13252.176.0.1 to 252.183.255.254252.183.255.255524,286
152252.184.0.0/13252.184.0.1 to 252.191.255.254252.191.255.255524,286
153252.192.0.0/13252.192.0.1 to 252.199.255.254252.199.255.255524,286
154252.200.0.0/13252.200.0.1 to 252.207.255.254252.207.255.255524,286
155252.208.0.0/13252.208.0.1 to 252.215.255.254252.215.255.255524,286
156252.216.0.0/13252.216.0.1 to 252.223.255.254252.223.255.255524,286
157252.224.0.0/13252.224.0.1 to 252.231.255.254252.231.255.255524,286
158252.232.0.0/13252.232.0.1 to 252.239.255.254252.239.255.255524,286
159252.240.0.0/13252.240.0.1 to 252.247.255.254252.247.255.255524,286
160252.248.0.0/13252.248.0.1 to 252.255.255.254252.255.255.255524,286
161253.0.0.0/13253.0.0.1 to 253.7.255.254253.7.255.255524,286
162253.8.0.0/13253.8.0.1 to 253.15.255.254253.15.255.255524,286
163253.16.0.0/13253.16.0.1 to 253.23.255.254253.23.255.255524,286
164253.24.0.0/13253.24.0.1 to 253.31.255.254253.31.255.255524,286
165253.32.0.0/13253.32.0.1 to 253.39.255.254253.39.255.255524,286
166253.40.0.0/13253.40.0.1 to 253.47.255.254253.47.255.255524,286
167253.48.0.0/13253.48.0.1 to 253.55.255.254253.55.255.255524,286
168253.56.0.0/13253.56.0.1 to 253.63.255.254253.63.255.255524,286
169253.64.0.0/13253.64.0.1 to 253.71.255.254253.71.255.255524,286
170253.72.0.0/13253.72.0.1 to 253.79.255.254253.79.255.255524,286
171253.80.0.0/13253.80.0.1 to 253.87.255.254253.87.255.255524,286
172253.88.0.0/13253.88.0.1 to 253.95.255.254253.95.255.255524,286
173253.96.0.0/13253.96.0.1 to 253.103.255.254253.103.255.255524,286
174253.104.0.0/13253.104.0.1 to 253.111.255.254253.111.255.255524,286
175253.112.0.0/13253.112.0.1 to 253.119.255.254253.119.255.255524,286
176253.120.0.0/13253.120.0.1 to 253.127.255.254253.127.255.255524,286
177253.128.0.0/13253.128.0.1 to 253.135.255.254253.135.255.255524,286
178253.136.0.0/13253.136.0.1 to 253.143.255.254253.143.255.255524,286
179253.144.0.0/13253.144.0.1 to 253.151.255.254253.151.255.255524,286
180253.152.0.0/13253.152.0.1 to 253.159.255.254253.159.255.255524,286
181253.160.0.0/13253.160.0.1 to 253.167.255.254253.167.255.255524,286
182253.168.0.0/13253.168.0.1 to 253.175.255.254253.175.255.255524,286
183253.176.0.0/13253.176.0.1 to 253.183.255.254253.183.255.255524,286
184253.184.0.0/13253.184.0.1 to 253.191.255.254253.191.255.255524,286
185253.192.0.0/13253.192.0.1 to 253.199.255.254253.199.255.255524,286
186253.200.0.0/13253.200.0.1 to 253.207.255.254253.207.255.255524,286
187253.208.0.0/13253.208.0.1 to 253.215.255.254253.215.255.255524,286
188253.216.0.0/13253.216.0.1 to 253.223.255.254253.223.255.255524,286
189253.224.0.0/13253.224.0.1 to 253.231.255.254253.231.255.255524,286
190253.232.0.0/13253.232.0.1 to 253.239.255.254253.239.255.255524,286
191253.240.0.0/13253.240.0.1 to 253.247.255.254253.247.255.255524,286
192253.248.0.0/13253.248.0.1 to 253.255.255.254253.255.255.255524,286
193254.0.0.0/13254.0.0.1 to 254.7.255.254254.7.255.255524,286
194254.8.0.0/13254.8.0.1 to 254.15.255.254254.15.255.255524,286
195254.16.0.0/13254.16.0.1 to 254.23.255.254254.23.255.255524,286
196254.24.0.0/13254.24.0.1 to 254.31.255.254254.31.255.255524,286
197254.32.0.0/13254.32.0.1 to 254.39.255.254254.39.255.255524,286
198254.40.0.0/13254.40.0.1 to 254.47.255.254254.47.255.255524,286
199254.48.0.0/13254.48.0.1 to 254.55.255.254254.55.255.255524,286
200254.56.0.0/13254.56.0.1 to 254.63.255.254254.63.255.255524,286
201254.64.0.0/13254.64.0.1 to 254.71.255.254254.71.255.255524,286
202254.72.0.0/13254.72.0.1 to 254.79.255.254254.79.255.255524,286
203254.80.0.0/13254.80.0.1 to 254.87.255.254254.87.255.255524,286
204254.88.0.0/13254.88.0.1 to 254.95.255.254254.95.255.255524,286
205254.96.0.0/13254.96.0.1 to 254.103.255.254254.103.255.255524,286
206254.104.0.0/13254.104.0.1 to 254.111.255.254254.111.255.255524,286
207254.112.0.0/13254.112.0.1 to 254.119.255.254254.119.255.255524,286
208254.120.0.0/13254.120.0.1 to 254.127.255.254254.127.255.255524,286
209254.128.0.0/13254.128.0.1 to 254.135.255.254254.135.255.255524,286
210254.136.0.0/13254.136.0.1 to 254.143.255.254254.143.255.255524,286
211254.144.0.0/13254.144.0.1 to 254.151.255.254254.151.255.255524,286
212254.152.0.0/13254.152.0.1 to 254.159.255.254254.159.255.255524,286
213254.160.0.0/13254.160.0.1 to 254.167.255.254254.167.255.255524,286
214254.168.0.0/13254.168.0.1 to 254.175.255.254254.175.255.255524,286
215254.176.0.0/13254.176.0.1 to 254.183.255.254254.183.255.255524,286
216254.184.0.0/13254.184.0.1 to 254.191.255.254254.191.255.255524,286
217254.192.0.0/13254.192.0.1 to 254.199.255.254254.199.255.255524,286
218254.200.0.0/13254.200.0.1 to 254.207.255.254254.207.255.255524,286
219254.208.0.0/13254.208.0.1 to 254.215.255.254254.215.255.255524,286
220254.216.0.0/13254.216.0.1 to 254.223.255.254254.223.255.255524,286
221254.224.0.0/13254.224.0.1 to 254.231.255.254254.231.255.255524,286
222254.232.0.0/13254.232.0.1 to 254.239.255.254254.239.255.255524,286
223254.240.0.0/13254.240.0.1 to 254.247.255.254254.247.255.255524,286
224254.248.0.0/13254.248.0.1 to 254.255.255.254254.255.255.255524,286
225255.0.0.0/13255.0.0.1 to 255.7.255.254255.7.255.255524,286
226255.8.0.0/13255.8.0.1 to 255.15.255.254255.15.255.255524,286
227255.16.0.0/13255.16.0.1 to 255.23.255.254255.23.255.255524,286
228255.24.0.0/13255.24.0.1 to 255.31.255.254255.31.255.255524,286
229255.32.0.0/13255.32.0.1 to 255.39.255.254255.39.255.255524,286
230255.40.0.0/13255.40.0.1 to 255.47.255.254255.47.255.255524,286
231255.48.0.0/13255.48.0.1 to 255.55.255.254255.55.255.255524,286
232255.56.0.0/13255.56.0.1 to 255.63.255.254255.63.255.255524,286
233255.64.0.0/13255.64.0.1 to 255.71.255.254255.71.255.255524,286
234255.72.0.0/13255.72.0.1 to 255.79.255.254255.79.255.255524,286
235255.80.0.0/13255.80.0.1 to 255.87.255.254255.87.255.255524,286
236255.88.0.0/13255.88.0.1 to 255.95.255.254255.95.255.255524,286
237255.96.0.0/13255.96.0.1 to 255.103.255.254255.103.255.255524,286
238255.104.0.0/13255.104.0.1 to 255.111.255.254255.111.255.255524,286
239255.112.0.0/13255.112.0.1 to 255.119.255.254255.119.255.255524,286
240255.120.0.0/13255.120.0.1 to 255.127.255.254255.127.255.255524,286
241255.128.0.0/13255.128.0.1 to 255.135.255.254255.135.255.255524,286
242255.136.0.0/13255.136.0.1 to 255.143.255.254255.143.255.255524,286
243255.144.0.0/13255.144.0.1 to 255.151.255.254255.151.255.255524,286
244255.152.0.0/13255.152.0.1 to 255.159.255.254255.159.255.255524,286
245255.160.0.0/13255.160.0.1 to 255.167.255.254255.167.255.255524,286
246255.168.0.0/13255.168.0.1 to 255.175.255.254255.175.255.255524,286
247255.176.0.0/13255.176.0.1 to 255.183.255.254255.183.255.255524,286
248255.184.0.0/13255.184.0.1 to 255.191.255.254255.191.255.255524,286
249255.192.0.0/13255.192.0.1 to 255.199.255.254255.199.255.255524,286
250255.200.0.0/13255.200.0.1 to 255.207.255.254255.207.255.255524,286
251255.208.0.0/13255.208.0.1 to 255.215.255.254255.215.255.255524,286
252255.216.0.0/13255.216.0.1 to 255.223.255.254255.223.255.255524,286
253255.224.0.0/13255.224.0.1 to 255.231.255.254255.231.255.255524,286
254255.232.0.0/13255.232.0.1 to 255.239.255.254255.239.255.255524,286
255255.240.0.0/13255.240.0.1 to 255.247.255.254255.247.255.255524,286
256255.248.0.0/13255.248.0.1 to 255.255.255.254255.255.255.255524,286

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.