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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.

Network248.48.0.0/12
Usable hosts1,048,574
Subnet mask255.240.0.0
Addresses1,048,576
Network address
248.48.0.0
Broadcast address
248.63.255.255
First usable
248.48.0.1
Last usable
248.63.255.254
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 F8300000 · Integer 4163895296 to 4164943871
Reverse DNS zones
48.248.in-addr.arpa
49.248.in-addr.arpa
50.248.in-addr.arpa
51.248.in-addr.arpa
52.248.in-addr.arpa
53.248.in-addr.arpa
54.248.in-addr.arpa
55.248.in-addr.arpa
56.248.in-addr.arpa
57.248.in-addr.arpa
58.248.in-addr.arpa
59.248.in-addr.arpa
60.248.in-addr.arpa
61.248.in-addr.arpa
62.248.in-addr.arpa
63.248.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
Address11111000.00110000.00000000.00000000248.48.0.0
Subnet mask11111111.11110000.00000000.00000000255.240.0.0
Network11111000.00110000.00000000.00000000248.48.0.0
Broadcast11111000.00111111.11111111.11111111248.63.255.255
Split into smaller subnets/20
/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)

248.48.0.0/12 makes 256 subnets of /20.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1248.48.0.0/20248.48.0.1 to 248.48.15.254248.48.15.2554,094
2248.48.16.0/20248.48.16.1 to 248.48.31.254248.48.31.2554,094
3248.48.32.0/20248.48.32.1 to 248.48.47.254248.48.47.2554,094
4248.48.48.0/20248.48.48.1 to 248.48.63.254248.48.63.2554,094
5248.48.64.0/20248.48.64.1 to 248.48.79.254248.48.79.2554,094
6248.48.80.0/20248.48.80.1 to 248.48.95.254248.48.95.2554,094
7248.48.96.0/20248.48.96.1 to 248.48.111.254248.48.111.2554,094
8248.48.112.0/20248.48.112.1 to 248.48.127.254248.48.127.2554,094
9248.48.128.0/20248.48.128.1 to 248.48.143.254248.48.143.2554,094
10248.48.144.0/20248.48.144.1 to 248.48.159.254248.48.159.2554,094
11248.48.160.0/20248.48.160.1 to 248.48.175.254248.48.175.2554,094
12248.48.176.0/20248.48.176.1 to 248.48.191.254248.48.191.2554,094
13248.48.192.0/20248.48.192.1 to 248.48.207.254248.48.207.2554,094
14248.48.208.0/20248.48.208.1 to 248.48.223.254248.48.223.2554,094
15248.48.224.0/20248.48.224.1 to 248.48.239.254248.48.239.2554,094
16248.48.240.0/20248.48.240.1 to 248.48.255.254248.48.255.2554,094
17248.49.0.0/20248.49.0.1 to 248.49.15.254248.49.15.2554,094
18248.49.16.0/20248.49.16.1 to 248.49.31.254248.49.31.2554,094
19248.49.32.0/20248.49.32.1 to 248.49.47.254248.49.47.2554,094
20248.49.48.0/20248.49.48.1 to 248.49.63.254248.49.63.2554,094
21248.49.64.0/20248.49.64.1 to 248.49.79.254248.49.79.2554,094
22248.49.80.0/20248.49.80.1 to 248.49.95.254248.49.95.2554,094
23248.49.96.0/20248.49.96.1 to 248.49.111.254248.49.111.2554,094
24248.49.112.0/20248.49.112.1 to 248.49.127.254248.49.127.2554,094
25248.49.128.0/20248.49.128.1 to 248.49.143.254248.49.143.2554,094
26248.49.144.0/20248.49.144.1 to 248.49.159.254248.49.159.2554,094
27248.49.160.0/20248.49.160.1 to 248.49.175.254248.49.175.2554,094
28248.49.176.0/20248.49.176.1 to 248.49.191.254248.49.191.2554,094
29248.49.192.0/20248.49.192.1 to 248.49.207.254248.49.207.2554,094
30248.49.208.0/20248.49.208.1 to 248.49.223.254248.49.223.2554,094
31248.49.224.0/20248.49.224.1 to 248.49.239.254248.49.239.2554,094
32248.49.240.0/20248.49.240.1 to 248.49.255.254248.49.255.2554,094
33248.50.0.0/20248.50.0.1 to 248.50.15.254248.50.15.2554,094
34248.50.16.0/20248.50.16.1 to 248.50.31.254248.50.31.2554,094
35248.50.32.0/20248.50.32.1 to 248.50.47.254248.50.47.2554,094
36248.50.48.0/20248.50.48.1 to 248.50.63.254248.50.63.2554,094
37248.50.64.0/20248.50.64.1 to 248.50.79.254248.50.79.2554,094
38248.50.80.0/20248.50.80.1 to 248.50.95.254248.50.95.2554,094
39248.50.96.0/20248.50.96.1 to 248.50.111.254248.50.111.2554,094
40248.50.112.0/20248.50.112.1 to 248.50.127.254248.50.127.2554,094
41248.50.128.0/20248.50.128.1 to 248.50.143.254248.50.143.2554,094
42248.50.144.0/20248.50.144.1 to 248.50.159.254248.50.159.2554,094
43248.50.160.0/20248.50.160.1 to 248.50.175.254248.50.175.2554,094
44248.50.176.0/20248.50.176.1 to 248.50.191.254248.50.191.2554,094
45248.50.192.0/20248.50.192.1 to 248.50.207.254248.50.207.2554,094
46248.50.208.0/20248.50.208.1 to 248.50.223.254248.50.223.2554,094
47248.50.224.0/20248.50.224.1 to 248.50.239.254248.50.239.2554,094
48248.50.240.0/20248.50.240.1 to 248.50.255.254248.50.255.2554,094
49248.51.0.0/20248.51.0.1 to 248.51.15.254248.51.15.2554,094
50248.51.16.0/20248.51.16.1 to 248.51.31.254248.51.31.2554,094
51248.51.32.0/20248.51.32.1 to 248.51.47.254248.51.47.2554,094
52248.51.48.0/20248.51.48.1 to 248.51.63.254248.51.63.2554,094
53248.51.64.0/20248.51.64.1 to 248.51.79.254248.51.79.2554,094
54248.51.80.0/20248.51.80.1 to 248.51.95.254248.51.95.2554,094
55248.51.96.0/20248.51.96.1 to 248.51.111.254248.51.111.2554,094
56248.51.112.0/20248.51.112.1 to 248.51.127.254248.51.127.2554,094
57248.51.128.0/20248.51.128.1 to 248.51.143.254248.51.143.2554,094
58248.51.144.0/20248.51.144.1 to 248.51.159.254248.51.159.2554,094
59248.51.160.0/20248.51.160.1 to 248.51.175.254248.51.175.2554,094
60248.51.176.0/20248.51.176.1 to 248.51.191.254248.51.191.2554,094
61248.51.192.0/20248.51.192.1 to 248.51.207.254248.51.207.2554,094
62248.51.208.0/20248.51.208.1 to 248.51.223.254248.51.223.2554,094
63248.51.224.0/20248.51.224.1 to 248.51.239.254248.51.239.2554,094
64248.51.240.0/20248.51.240.1 to 248.51.255.254248.51.255.2554,094
65248.52.0.0/20248.52.0.1 to 248.52.15.254248.52.15.2554,094
66248.52.16.0/20248.52.16.1 to 248.52.31.254248.52.31.2554,094
67248.52.32.0/20248.52.32.1 to 248.52.47.254248.52.47.2554,094
68248.52.48.0/20248.52.48.1 to 248.52.63.254248.52.63.2554,094
69248.52.64.0/20248.52.64.1 to 248.52.79.254248.52.79.2554,094
70248.52.80.0/20248.52.80.1 to 248.52.95.254248.52.95.2554,094
71248.52.96.0/20248.52.96.1 to 248.52.111.254248.52.111.2554,094
72248.52.112.0/20248.52.112.1 to 248.52.127.254248.52.127.2554,094
73248.52.128.0/20248.52.128.1 to 248.52.143.254248.52.143.2554,094
74248.52.144.0/20248.52.144.1 to 248.52.159.254248.52.159.2554,094
75248.52.160.0/20248.52.160.1 to 248.52.175.254248.52.175.2554,094
76248.52.176.0/20248.52.176.1 to 248.52.191.254248.52.191.2554,094
77248.52.192.0/20248.52.192.1 to 248.52.207.254248.52.207.2554,094
78248.52.208.0/20248.52.208.1 to 248.52.223.254248.52.223.2554,094
79248.52.224.0/20248.52.224.1 to 248.52.239.254248.52.239.2554,094
80248.52.240.0/20248.52.240.1 to 248.52.255.254248.52.255.2554,094
81248.53.0.0/20248.53.0.1 to 248.53.15.254248.53.15.2554,094
82248.53.16.0/20248.53.16.1 to 248.53.31.254248.53.31.2554,094
83248.53.32.0/20248.53.32.1 to 248.53.47.254248.53.47.2554,094
84248.53.48.0/20248.53.48.1 to 248.53.63.254248.53.63.2554,094
85248.53.64.0/20248.53.64.1 to 248.53.79.254248.53.79.2554,094
86248.53.80.0/20248.53.80.1 to 248.53.95.254248.53.95.2554,094
87248.53.96.0/20248.53.96.1 to 248.53.111.254248.53.111.2554,094
88248.53.112.0/20248.53.112.1 to 248.53.127.254248.53.127.2554,094
89248.53.128.0/20248.53.128.1 to 248.53.143.254248.53.143.2554,094
90248.53.144.0/20248.53.144.1 to 248.53.159.254248.53.159.2554,094
91248.53.160.0/20248.53.160.1 to 248.53.175.254248.53.175.2554,094
92248.53.176.0/20248.53.176.1 to 248.53.191.254248.53.191.2554,094
93248.53.192.0/20248.53.192.1 to 248.53.207.254248.53.207.2554,094
94248.53.208.0/20248.53.208.1 to 248.53.223.254248.53.223.2554,094
95248.53.224.0/20248.53.224.1 to 248.53.239.254248.53.239.2554,094
96248.53.240.0/20248.53.240.1 to 248.53.255.254248.53.255.2554,094
97248.54.0.0/20248.54.0.1 to 248.54.15.254248.54.15.2554,094
98248.54.16.0/20248.54.16.1 to 248.54.31.254248.54.31.2554,094
99248.54.32.0/20248.54.32.1 to 248.54.47.254248.54.47.2554,094
100248.54.48.0/20248.54.48.1 to 248.54.63.254248.54.63.2554,094
101248.54.64.0/20248.54.64.1 to 248.54.79.254248.54.79.2554,094
102248.54.80.0/20248.54.80.1 to 248.54.95.254248.54.95.2554,094
103248.54.96.0/20248.54.96.1 to 248.54.111.254248.54.111.2554,094
104248.54.112.0/20248.54.112.1 to 248.54.127.254248.54.127.2554,094
105248.54.128.0/20248.54.128.1 to 248.54.143.254248.54.143.2554,094
106248.54.144.0/20248.54.144.1 to 248.54.159.254248.54.159.2554,094
107248.54.160.0/20248.54.160.1 to 248.54.175.254248.54.175.2554,094
108248.54.176.0/20248.54.176.1 to 248.54.191.254248.54.191.2554,094
109248.54.192.0/20248.54.192.1 to 248.54.207.254248.54.207.2554,094
110248.54.208.0/20248.54.208.1 to 248.54.223.254248.54.223.2554,094
111248.54.224.0/20248.54.224.1 to 248.54.239.254248.54.239.2554,094
112248.54.240.0/20248.54.240.1 to 248.54.255.254248.54.255.2554,094
113248.55.0.0/20248.55.0.1 to 248.55.15.254248.55.15.2554,094
114248.55.16.0/20248.55.16.1 to 248.55.31.254248.55.31.2554,094
115248.55.32.0/20248.55.32.1 to 248.55.47.254248.55.47.2554,094
116248.55.48.0/20248.55.48.1 to 248.55.63.254248.55.63.2554,094
117248.55.64.0/20248.55.64.1 to 248.55.79.254248.55.79.2554,094
118248.55.80.0/20248.55.80.1 to 248.55.95.254248.55.95.2554,094
119248.55.96.0/20248.55.96.1 to 248.55.111.254248.55.111.2554,094
120248.55.112.0/20248.55.112.1 to 248.55.127.254248.55.127.2554,094
121248.55.128.0/20248.55.128.1 to 248.55.143.254248.55.143.2554,094
122248.55.144.0/20248.55.144.1 to 248.55.159.254248.55.159.2554,094
123248.55.160.0/20248.55.160.1 to 248.55.175.254248.55.175.2554,094
124248.55.176.0/20248.55.176.1 to 248.55.191.254248.55.191.2554,094
125248.55.192.0/20248.55.192.1 to 248.55.207.254248.55.207.2554,094
126248.55.208.0/20248.55.208.1 to 248.55.223.254248.55.223.2554,094
127248.55.224.0/20248.55.224.1 to 248.55.239.254248.55.239.2554,094
128248.55.240.0/20248.55.240.1 to 248.55.255.254248.55.255.2554,094
129248.56.0.0/20248.56.0.1 to 248.56.15.254248.56.15.2554,094
130248.56.16.0/20248.56.16.1 to 248.56.31.254248.56.31.2554,094
131248.56.32.0/20248.56.32.1 to 248.56.47.254248.56.47.2554,094
132248.56.48.0/20248.56.48.1 to 248.56.63.254248.56.63.2554,094
133248.56.64.0/20248.56.64.1 to 248.56.79.254248.56.79.2554,094
134248.56.80.0/20248.56.80.1 to 248.56.95.254248.56.95.2554,094
135248.56.96.0/20248.56.96.1 to 248.56.111.254248.56.111.2554,094
136248.56.112.0/20248.56.112.1 to 248.56.127.254248.56.127.2554,094
137248.56.128.0/20248.56.128.1 to 248.56.143.254248.56.143.2554,094
138248.56.144.0/20248.56.144.1 to 248.56.159.254248.56.159.2554,094
139248.56.160.0/20248.56.160.1 to 248.56.175.254248.56.175.2554,094
140248.56.176.0/20248.56.176.1 to 248.56.191.254248.56.191.2554,094
141248.56.192.0/20248.56.192.1 to 248.56.207.254248.56.207.2554,094
142248.56.208.0/20248.56.208.1 to 248.56.223.254248.56.223.2554,094
143248.56.224.0/20248.56.224.1 to 248.56.239.254248.56.239.2554,094
144248.56.240.0/20248.56.240.1 to 248.56.255.254248.56.255.2554,094
145248.57.0.0/20248.57.0.1 to 248.57.15.254248.57.15.2554,094
146248.57.16.0/20248.57.16.1 to 248.57.31.254248.57.31.2554,094
147248.57.32.0/20248.57.32.1 to 248.57.47.254248.57.47.2554,094
148248.57.48.0/20248.57.48.1 to 248.57.63.254248.57.63.2554,094
149248.57.64.0/20248.57.64.1 to 248.57.79.254248.57.79.2554,094
150248.57.80.0/20248.57.80.1 to 248.57.95.254248.57.95.2554,094
151248.57.96.0/20248.57.96.1 to 248.57.111.254248.57.111.2554,094
152248.57.112.0/20248.57.112.1 to 248.57.127.254248.57.127.2554,094
153248.57.128.0/20248.57.128.1 to 248.57.143.254248.57.143.2554,094
154248.57.144.0/20248.57.144.1 to 248.57.159.254248.57.159.2554,094
155248.57.160.0/20248.57.160.1 to 248.57.175.254248.57.175.2554,094
156248.57.176.0/20248.57.176.1 to 248.57.191.254248.57.191.2554,094
157248.57.192.0/20248.57.192.1 to 248.57.207.254248.57.207.2554,094
158248.57.208.0/20248.57.208.1 to 248.57.223.254248.57.223.2554,094
159248.57.224.0/20248.57.224.1 to 248.57.239.254248.57.239.2554,094
160248.57.240.0/20248.57.240.1 to 248.57.255.254248.57.255.2554,094
161248.58.0.0/20248.58.0.1 to 248.58.15.254248.58.15.2554,094
162248.58.16.0/20248.58.16.1 to 248.58.31.254248.58.31.2554,094
163248.58.32.0/20248.58.32.1 to 248.58.47.254248.58.47.2554,094
164248.58.48.0/20248.58.48.1 to 248.58.63.254248.58.63.2554,094
165248.58.64.0/20248.58.64.1 to 248.58.79.254248.58.79.2554,094
166248.58.80.0/20248.58.80.1 to 248.58.95.254248.58.95.2554,094
167248.58.96.0/20248.58.96.1 to 248.58.111.254248.58.111.2554,094
168248.58.112.0/20248.58.112.1 to 248.58.127.254248.58.127.2554,094
169248.58.128.0/20248.58.128.1 to 248.58.143.254248.58.143.2554,094
170248.58.144.0/20248.58.144.1 to 248.58.159.254248.58.159.2554,094
171248.58.160.0/20248.58.160.1 to 248.58.175.254248.58.175.2554,094
172248.58.176.0/20248.58.176.1 to 248.58.191.254248.58.191.2554,094
173248.58.192.0/20248.58.192.1 to 248.58.207.254248.58.207.2554,094
174248.58.208.0/20248.58.208.1 to 248.58.223.254248.58.223.2554,094
175248.58.224.0/20248.58.224.1 to 248.58.239.254248.58.239.2554,094
176248.58.240.0/20248.58.240.1 to 248.58.255.254248.58.255.2554,094
177248.59.0.0/20248.59.0.1 to 248.59.15.254248.59.15.2554,094
178248.59.16.0/20248.59.16.1 to 248.59.31.254248.59.31.2554,094
179248.59.32.0/20248.59.32.1 to 248.59.47.254248.59.47.2554,094
180248.59.48.0/20248.59.48.1 to 248.59.63.254248.59.63.2554,094
181248.59.64.0/20248.59.64.1 to 248.59.79.254248.59.79.2554,094
182248.59.80.0/20248.59.80.1 to 248.59.95.254248.59.95.2554,094
183248.59.96.0/20248.59.96.1 to 248.59.111.254248.59.111.2554,094
184248.59.112.0/20248.59.112.1 to 248.59.127.254248.59.127.2554,094
185248.59.128.0/20248.59.128.1 to 248.59.143.254248.59.143.2554,094
186248.59.144.0/20248.59.144.1 to 248.59.159.254248.59.159.2554,094
187248.59.160.0/20248.59.160.1 to 248.59.175.254248.59.175.2554,094
188248.59.176.0/20248.59.176.1 to 248.59.191.254248.59.191.2554,094
189248.59.192.0/20248.59.192.1 to 248.59.207.254248.59.207.2554,094
190248.59.208.0/20248.59.208.1 to 248.59.223.254248.59.223.2554,094
191248.59.224.0/20248.59.224.1 to 248.59.239.254248.59.239.2554,094
192248.59.240.0/20248.59.240.1 to 248.59.255.254248.59.255.2554,094
193248.60.0.0/20248.60.0.1 to 248.60.15.254248.60.15.2554,094
194248.60.16.0/20248.60.16.1 to 248.60.31.254248.60.31.2554,094
195248.60.32.0/20248.60.32.1 to 248.60.47.254248.60.47.2554,094
196248.60.48.0/20248.60.48.1 to 248.60.63.254248.60.63.2554,094
197248.60.64.0/20248.60.64.1 to 248.60.79.254248.60.79.2554,094
198248.60.80.0/20248.60.80.1 to 248.60.95.254248.60.95.2554,094
199248.60.96.0/20248.60.96.1 to 248.60.111.254248.60.111.2554,094
200248.60.112.0/20248.60.112.1 to 248.60.127.254248.60.127.2554,094
201248.60.128.0/20248.60.128.1 to 248.60.143.254248.60.143.2554,094
202248.60.144.0/20248.60.144.1 to 248.60.159.254248.60.159.2554,094
203248.60.160.0/20248.60.160.1 to 248.60.175.254248.60.175.2554,094
204248.60.176.0/20248.60.176.1 to 248.60.191.254248.60.191.2554,094
205248.60.192.0/20248.60.192.1 to 248.60.207.254248.60.207.2554,094
206248.60.208.0/20248.60.208.1 to 248.60.223.254248.60.223.2554,094
207248.60.224.0/20248.60.224.1 to 248.60.239.254248.60.239.2554,094
208248.60.240.0/20248.60.240.1 to 248.60.255.254248.60.255.2554,094
209248.61.0.0/20248.61.0.1 to 248.61.15.254248.61.15.2554,094
210248.61.16.0/20248.61.16.1 to 248.61.31.254248.61.31.2554,094
211248.61.32.0/20248.61.32.1 to 248.61.47.254248.61.47.2554,094
212248.61.48.0/20248.61.48.1 to 248.61.63.254248.61.63.2554,094
213248.61.64.0/20248.61.64.1 to 248.61.79.254248.61.79.2554,094
214248.61.80.0/20248.61.80.1 to 248.61.95.254248.61.95.2554,094
215248.61.96.0/20248.61.96.1 to 248.61.111.254248.61.111.2554,094
216248.61.112.0/20248.61.112.1 to 248.61.127.254248.61.127.2554,094
217248.61.128.0/20248.61.128.1 to 248.61.143.254248.61.143.2554,094
218248.61.144.0/20248.61.144.1 to 248.61.159.254248.61.159.2554,094
219248.61.160.0/20248.61.160.1 to 248.61.175.254248.61.175.2554,094
220248.61.176.0/20248.61.176.1 to 248.61.191.254248.61.191.2554,094
221248.61.192.0/20248.61.192.1 to 248.61.207.254248.61.207.2554,094
222248.61.208.0/20248.61.208.1 to 248.61.223.254248.61.223.2554,094
223248.61.224.0/20248.61.224.1 to 248.61.239.254248.61.239.2554,094
224248.61.240.0/20248.61.240.1 to 248.61.255.254248.61.255.2554,094
225248.62.0.0/20248.62.0.1 to 248.62.15.254248.62.15.2554,094
226248.62.16.0/20248.62.16.1 to 248.62.31.254248.62.31.2554,094
227248.62.32.0/20248.62.32.1 to 248.62.47.254248.62.47.2554,094
228248.62.48.0/20248.62.48.1 to 248.62.63.254248.62.63.2554,094
229248.62.64.0/20248.62.64.1 to 248.62.79.254248.62.79.2554,094
230248.62.80.0/20248.62.80.1 to 248.62.95.254248.62.95.2554,094
231248.62.96.0/20248.62.96.1 to 248.62.111.254248.62.111.2554,094
232248.62.112.0/20248.62.112.1 to 248.62.127.254248.62.127.2554,094
233248.62.128.0/20248.62.128.1 to 248.62.143.254248.62.143.2554,094
234248.62.144.0/20248.62.144.1 to 248.62.159.254248.62.159.2554,094
235248.62.160.0/20248.62.160.1 to 248.62.175.254248.62.175.2554,094
236248.62.176.0/20248.62.176.1 to 248.62.191.254248.62.191.2554,094
237248.62.192.0/20248.62.192.1 to 248.62.207.254248.62.207.2554,094
238248.62.208.0/20248.62.208.1 to 248.62.223.254248.62.223.2554,094
239248.62.224.0/20248.62.224.1 to 248.62.239.254248.62.239.2554,094
240248.62.240.0/20248.62.240.1 to 248.62.255.254248.62.255.2554,094
241248.63.0.0/20248.63.0.1 to 248.63.15.254248.63.15.2554,094
242248.63.16.0/20248.63.16.1 to 248.63.31.254248.63.31.2554,094
243248.63.32.0/20248.63.32.1 to 248.63.47.254248.63.47.2554,094
244248.63.48.0/20248.63.48.1 to 248.63.63.254248.63.63.2554,094
245248.63.64.0/20248.63.64.1 to 248.63.79.254248.63.79.2554,094
246248.63.80.0/20248.63.80.1 to 248.63.95.254248.63.95.2554,094
247248.63.96.0/20248.63.96.1 to 248.63.111.254248.63.111.2554,094
248248.63.112.0/20248.63.112.1 to 248.63.127.254248.63.127.2554,094
249248.63.128.0/20248.63.128.1 to 248.63.143.254248.63.143.2554,094
250248.63.144.0/20248.63.144.1 to 248.63.159.254248.63.159.2554,094
251248.63.160.0/20248.63.160.1 to 248.63.175.254248.63.175.2554,094
252248.63.176.0/20248.63.176.1 to 248.63.191.254248.63.191.2554,094
253248.63.192.0/20248.63.192.1 to 248.63.207.254248.63.207.2554,094
254248.63.208.0/20248.63.208.1 to 248.63.223.254248.63.223.2554,094
255248.63.224.0/20248.63.224.1 to 248.63.239.254248.63.239.2554,094
256248.63.240.0/20248.63.240.1 to 248.63.255.254248.63.255.2554,094

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.