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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.

Network247.48.0.0/12
Usable hosts1,048,574
Subnet mask255.240.0.0
Addresses1,048,576
Network address
247.48.0.0
Broadcast address
247.63.255.255
First usable
247.48.0.1
Last usable
247.63.255.254
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 F7300000 · Integer 4147118080 to 4148166655
Reverse DNS zones
48.247.in-addr.arpa
49.247.in-addr.arpa
50.247.in-addr.arpa
51.247.in-addr.arpa
52.247.in-addr.arpa
53.247.in-addr.arpa
54.247.in-addr.arpa
55.247.in-addr.arpa
56.247.in-addr.arpa
57.247.in-addr.arpa
58.247.in-addr.arpa
59.247.in-addr.arpa
60.247.in-addr.arpa
61.247.in-addr.arpa
62.247.in-addr.arpa
63.247.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
Address11110111.00110000.00000000.00000000247.48.0.0
Subnet mask11111111.11110000.00000000.00000000255.240.0.0
Network11110111.00110000.00000000.00000000247.48.0.0
Broadcast11110111.00111111.11111111.11111111247.63.255.255
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)

247.48.0.0/12 makes 256 subnets of /20.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1247.48.0.0/20247.48.0.1 to 247.48.15.254247.48.15.2554,094
2247.48.16.0/20247.48.16.1 to 247.48.31.254247.48.31.2554,094
3247.48.32.0/20247.48.32.1 to 247.48.47.254247.48.47.2554,094
4247.48.48.0/20247.48.48.1 to 247.48.63.254247.48.63.2554,094
5247.48.64.0/20247.48.64.1 to 247.48.79.254247.48.79.2554,094
6247.48.80.0/20247.48.80.1 to 247.48.95.254247.48.95.2554,094
7247.48.96.0/20247.48.96.1 to 247.48.111.254247.48.111.2554,094
8247.48.112.0/20247.48.112.1 to 247.48.127.254247.48.127.2554,094
9247.48.128.0/20247.48.128.1 to 247.48.143.254247.48.143.2554,094
10247.48.144.0/20247.48.144.1 to 247.48.159.254247.48.159.2554,094
11247.48.160.0/20247.48.160.1 to 247.48.175.254247.48.175.2554,094
12247.48.176.0/20247.48.176.1 to 247.48.191.254247.48.191.2554,094
13247.48.192.0/20247.48.192.1 to 247.48.207.254247.48.207.2554,094
14247.48.208.0/20247.48.208.1 to 247.48.223.254247.48.223.2554,094
15247.48.224.0/20247.48.224.1 to 247.48.239.254247.48.239.2554,094
16247.48.240.0/20247.48.240.1 to 247.48.255.254247.48.255.2554,094
17247.49.0.0/20247.49.0.1 to 247.49.15.254247.49.15.2554,094
18247.49.16.0/20247.49.16.1 to 247.49.31.254247.49.31.2554,094
19247.49.32.0/20247.49.32.1 to 247.49.47.254247.49.47.2554,094
20247.49.48.0/20247.49.48.1 to 247.49.63.254247.49.63.2554,094
21247.49.64.0/20247.49.64.1 to 247.49.79.254247.49.79.2554,094
22247.49.80.0/20247.49.80.1 to 247.49.95.254247.49.95.2554,094
23247.49.96.0/20247.49.96.1 to 247.49.111.254247.49.111.2554,094
24247.49.112.0/20247.49.112.1 to 247.49.127.254247.49.127.2554,094
25247.49.128.0/20247.49.128.1 to 247.49.143.254247.49.143.2554,094
26247.49.144.0/20247.49.144.1 to 247.49.159.254247.49.159.2554,094
27247.49.160.0/20247.49.160.1 to 247.49.175.254247.49.175.2554,094
28247.49.176.0/20247.49.176.1 to 247.49.191.254247.49.191.2554,094
29247.49.192.0/20247.49.192.1 to 247.49.207.254247.49.207.2554,094
30247.49.208.0/20247.49.208.1 to 247.49.223.254247.49.223.2554,094
31247.49.224.0/20247.49.224.1 to 247.49.239.254247.49.239.2554,094
32247.49.240.0/20247.49.240.1 to 247.49.255.254247.49.255.2554,094
33247.50.0.0/20247.50.0.1 to 247.50.15.254247.50.15.2554,094
34247.50.16.0/20247.50.16.1 to 247.50.31.254247.50.31.2554,094
35247.50.32.0/20247.50.32.1 to 247.50.47.254247.50.47.2554,094
36247.50.48.0/20247.50.48.1 to 247.50.63.254247.50.63.2554,094
37247.50.64.0/20247.50.64.1 to 247.50.79.254247.50.79.2554,094
38247.50.80.0/20247.50.80.1 to 247.50.95.254247.50.95.2554,094
39247.50.96.0/20247.50.96.1 to 247.50.111.254247.50.111.2554,094
40247.50.112.0/20247.50.112.1 to 247.50.127.254247.50.127.2554,094
41247.50.128.0/20247.50.128.1 to 247.50.143.254247.50.143.2554,094
42247.50.144.0/20247.50.144.1 to 247.50.159.254247.50.159.2554,094
43247.50.160.0/20247.50.160.1 to 247.50.175.254247.50.175.2554,094
44247.50.176.0/20247.50.176.1 to 247.50.191.254247.50.191.2554,094
45247.50.192.0/20247.50.192.1 to 247.50.207.254247.50.207.2554,094
46247.50.208.0/20247.50.208.1 to 247.50.223.254247.50.223.2554,094
47247.50.224.0/20247.50.224.1 to 247.50.239.254247.50.239.2554,094
48247.50.240.0/20247.50.240.1 to 247.50.255.254247.50.255.2554,094
49247.51.0.0/20247.51.0.1 to 247.51.15.254247.51.15.2554,094
50247.51.16.0/20247.51.16.1 to 247.51.31.254247.51.31.2554,094
51247.51.32.0/20247.51.32.1 to 247.51.47.254247.51.47.2554,094
52247.51.48.0/20247.51.48.1 to 247.51.63.254247.51.63.2554,094
53247.51.64.0/20247.51.64.1 to 247.51.79.254247.51.79.2554,094
54247.51.80.0/20247.51.80.1 to 247.51.95.254247.51.95.2554,094
55247.51.96.0/20247.51.96.1 to 247.51.111.254247.51.111.2554,094
56247.51.112.0/20247.51.112.1 to 247.51.127.254247.51.127.2554,094
57247.51.128.0/20247.51.128.1 to 247.51.143.254247.51.143.2554,094
58247.51.144.0/20247.51.144.1 to 247.51.159.254247.51.159.2554,094
59247.51.160.0/20247.51.160.1 to 247.51.175.254247.51.175.2554,094
60247.51.176.0/20247.51.176.1 to 247.51.191.254247.51.191.2554,094
61247.51.192.0/20247.51.192.1 to 247.51.207.254247.51.207.2554,094
62247.51.208.0/20247.51.208.1 to 247.51.223.254247.51.223.2554,094
63247.51.224.0/20247.51.224.1 to 247.51.239.254247.51.239.2554,094
64247.51.240.0/20247.51.240.1 to 247.51.255.254247.51.255.2554,094
65247.52.0.0/20247.52.0.1 to 247.52.15.254247.52.15.2554,094
66247.52.16.0/20247.52.16.1 to 247.52.31.254247.52.31.2554,094
67247.52.32.0/20247.52.32.1 to 247.52.47.254247.52.47.2554,094
68247.52.48.0/20247.52.48.1 to 247.52.63.254247.52.63.2554,094
69247.52.64.0/20247.52.64.1 to 247.52.79.254247.52.79.2554,094
70247.52.80.0/20247.52.80.1 to 247.52.95.254247.52.95.2554,094
71247.52.96.0/20247.52.96.1 to 247.52.111.254247.52.111.2554,094
72247.52.112.0/20247.52.112.1 to 247.52.127.254247.52.127.2554,094
73247.52.128.0/20247.52.128.1 to 247.52.143.254247.52.143.2554,094
74247.52.144.0/20247.52.144.1 to 247.52.159.254247.52.159.2554,094
75247.52.160.0/20247.52.160.1 to 247.52.175.254247.52.175.2554,094
76247.52.176.0/20247.52.176.1 to 247.52.191.254247.52.191.2554,094
77247.52.192.0/20247.52.192.1 to 247.52.207.254247.52.207.2554,094
78247.52.208.0/20247.52.208.1 to 247.52.223.254247.52.223.2554,094
79247.52.224.0/20247.52.224.1 to 247.52.239.254247.52.239.2554,094
80247.52.240.0/20247.52.240.1 to 247.52.255.254247.52.255.2554,094
81247.53.0.0/20247.53.0.1 to 247.53.15.254247.53.15.2554,094
82247.53.16.0/20247.53.16.1 to 247.53.31.254247.53.31.2554,094
83247.53.32.0/20247.53.32.1 to 247.53.47.254247.53.47.2554,094
84247.53.48.0/20247.53.48.1 to 247.53.63.254247.53.63.2554,094
85247.53.64.0/20247.53.64.1 to 247.53.79.254247.53.79.2554,094
86247.53.80.0/20247.53.80.1 to 247.53.95.254247.53.95.2554,094
87247.53.96.0/20247.53.96.1 to 247.53.111.254247.53.111.2554,094
88247.53.112.0/20247.53.112.1 to 247.53.127.254247.53.127.2554,094
89247.53.128.0/20247.53.128.1 to 247.53.143.254247.53.143.2554,094
90247.53.144.0/20247.53.144.1 to 247.53.159.254247.53.159.2554,094
91247.53.160.0/20247.53.160.1 to 247.53.175.254247.53.175.2554,094
92247.53.176.0/20247.53.176.1 to 247.53.191.254247.53.191.2554,094
93247.53.192.0/20247.53.192.1 to 247.53.207.254247.53.207.2554,094
94247.53.208.0/20247.53.208.1 to 247.53.223.254247.53.223.2554,094
95247.53.224.0/20247.53.224.1 to 247.53.239.254247.53.239.2554,094
96247.53.240.0/20247.53.240.1 to 247.53.255.254247.53.255.2554,094
97247.54.0.0/20247.54.0.1 to 247.54.15.254247.54.15.2554,094
98247.54.16.0/20247.54.16.1 to 247.54.31.254247.54.31.2554,094
99247.54.32.0/20247.54.32.1 to 247.54.47.254247.54.47.2554,094
100247.54.48.0/20247.54.48.1 to 247.54.63.254247.54.63.2554,094
101247.54.64.0/20247.54.64.1 to 247.54.79.254247.54.79.2554,094
102247.54.80.0/20247.54.80.1 to 247.54.95.254247.54.95.2554,094
103247.54.96.0/20247.54.96.1 to 247.54.111.254247.54.111.2554,094
104247.54.112.0/20247.54.112.1 to 247.54.127.254247.54.127.2554,094
105247.54.128.0/20247.54.128.1 to 247.54.143.254247.54.143.2554,094
106247.54.144.0/20247.54.144.1 to 247.54.159.254247.54.159.2554,094
107247.54.160.0/20247.54.160.1 to 247.54.175.254247.54.175.2554,094
108247.54.176.0/20247.54.176.1 to 247.54.191.254247.54.191.2554,094
109247.54.192.0/20247.54.192.1 to 247.54.207.254247.54.207.2554,094
110247.54.208.0/20247.54.208.1 to 247.54.223.254247.54.223.2554,094
111247.54.224.0/20247.54.224.1 to 247.54.239.254247.54.239.2554,094
112247.54.240.0/20247.54.240.1 to 247.54.255.254247.54.255.2554,094
113247.55.0.0/20247.55.0.1 to 247.55.15.254247.55.15.2554,094
114247.55.16.0/20247.55.16.1 to 247.55.31.254247.55.31.2554,094
115247.55.32.0/20247.55.32.1 to 247.55.47.254247.55.47.2554,094
116247.55.48.0/20247.55.48.1 to 247.55.63.254247.55.63.2554,094
117247.55.64.0/20247.55.64.1 to 247.55.79.254247.55.79.2554,094
118247.55.80.0/20247.55.80.1 to 247.55.95.254247.55.95.2554,094
119247.55.96.0/20247.55.96.1 to 247.55.111.254247.55.111.2554,094
120247.55.112.0/20247.55.112.1 to 247.55.127.254247.55.127.2554,094
121247.55.128.0/20247.55.128.1 to 247.55.143.254247.55.143.2554,094
122247.55.144.0/20247.55.144.1 to 247.55.159.254247.55.159.2554,094
123247.55.160.0/20247.55.160.1 to 247.55.175.254247.55.175.2554,094
124247.55.176.0/20247.55.176.1 to 247.55.191.254247.55.191.2554,094
125247.55.192.0/20247.55.192.1 to 247.55.207.254247.55.207.2554,094
126247.55.208.0/20247.55.208.1 to 247.55.223.254247.55.223.2554,094
127247.55.224.0/20247.55.224.1 to 247.55.239.254247.55.239.2554,094
128247.55.240.0/20247.55.240.1 to 247.55.255.254247.55.255.2554,094
129247.56.0.0/20247.56.0.1 to 247.56.15.254247.56.15.2554,094
130247.56.16.0/20247.56.16.1 to 247.56.31.254247.56.31.2554,094
131247.56.32.0/20247.56.32.1 to 247.56.47.254247.56.47.2554,094
132247.56.48.0/20247.56.48.1 to 247.56.63.254247.56.63.2554,094
133247.56.64.0/20247.56.64.1 to 247.56.79.254247.56.79.2554,094
134247.56.80.0/20247.56.80.1 to 247.56.95.254247.56.95.2554,094
135247.56.96.0/20247.56.96.1 to 247.56.111.254247.56.111.2554,094
136247.56.112.0/20247.56.112.1 to 247.56.127.254247.56.127.2554,094
137247.56.128.0/20247.56.128.1 to 247.56.143.254247.56.143.2554,094
138247.56.144.0/20247.56.144.1 to 247.56.159.254247.56.159.2554,094
139247.56.160.0/20247.56.160.1 to 247.56.175.254247.56.175.2554,094
140247.56.176.0/20247.56.176.1 to 247.56.191.254247.56.191.2554,094
141247.56.192.0/20247.56.192.1 to 247.56.207.254247.56.207.2554,094
142247.56.208.0/20247.56.208.1 to 247.56.223.254247.56.223.2554,094
143247.56.224.0/20247.56.224.1 to 247.56.239.254247.56.239.2554,094
144247.56.240.0/20247.56.240.1 to 247.56.255.254247.56.255.2554,094
145247.57.0.0/20247.57.0.1 to 247.57.15.254247.57.15.2554,094
146247.57.16.0/20247.57.16.1 to 247.57.31.254247.57.31.2554,094
147247.57.32.0/20247.57.32.1 to 247.57.47.254247.57.47.2554,094
148247.57.48.0/20247.57.48.1 to 247.57.63.254247.57.63.2554,094
149247.57.64.0/20247.57.64.1 to 247.57.79.254247.57.79.2554,094
150247.57.80.0/20247.57.80.1 to 247.57.95.254247.57.95.2554,094
151247.57.96.0/20247.57.96.1 to 247.57.111.254247.57.111.2554,094
152247.57.112.0/20247.57.112.1 to 247.57.127.254247.57.127.2554,094
153247.57.128.0/20247.57.128.1 to 247.57.143.254247.57.143.2554,094
154247.57.144.0/20247.57.144.1 to 247.57.159.254247.57.159.2554,094
155247.57.160.0/20247.57.160.1 to 247.57.175.254247.57.175.2554,094
156247.57.176.0/20247.57.176.1 to 247.57.191.254247.57.191.2554,094
157247.57.192.0/20247.57.192.1 to 247.57.207.254247.57.207.2554,094
158247.57.208.0/20247.57.208.1 to 247.57.223.254247.57.223.2554,094
159247.57.224.0/20247.57.224.1 to 247.57.239.254247.57.239.2554,094
160247.57.240.0/20247.57.240.1 to 247.57.255.254247.57.255.2554,094
161247.58.0.0/20247.58.0.1 to 247.58.15.254247.58.15.2554,094
162247.58.16.0/20247.58.16.1 to 247.58.31.254247.58.31.2554,094
163247.58.32.0/20247.58.32.1 to 247.58.47.254247.58.47.2554,094
164247.58.48.0/20247.58.48.1 to 247.58.63.254247.58.63.2554,094
165247.58.64.0/20247.58.64.1 to 247.58.79.254247.58.79.2554,094
166247.58.80.0/20247.58.80.1 to 247.58.95.254247.58.95.2554,094
167247.58.96.0/20247.58.96.1 to 247.58.111.254247.58.111.2554,094
168247.58.112.0/20247.58.112.1 to 247.58.127.254247.58.127.2554,094
169247.58.128.0/20247.58.128.1 to 247.58.143.254247.58.143.2554,094
170247.58.144.0/20247.58.144.1 to 247.58.159.254247.58.159.2554,094
171247.58.160.0/20247.58.160.1 to 247.58.175.254247.58.175.2554,094
172247.58.176.0/20247.58.176.1 to 247.58.191.254247.58.191.2554,094
173247.58.192.0/20247.58.192.1 to 247.58.207.254247.58.207.2554,094
174247.58.208.0/20247.58.208.1 to 247.58.223.254247.58.223.2554,094
175247.58.224.0/20247.58.224.1 to 247.58.239.254247.58.239.2554,094
176247.58.240.0/20247.58.240.1 to 247.58.255.254247.58.255.2554,094
177247.59.0.0/20247.59.0.1 to 247.59.15.254247.59.15.2554,094
178247.59.16.0/20247.59.16.1 to 247.59.31.254247.59.31.2554,094
179247.59.32.0/20247.59.32.1 to 247.59.47.254247.59.47.2554,094
180247.59.48.0/20247.59.48.1 to 247.59.63.254247.59.63.2554,094
181247.59.64.0/20247.59.64.1 to 247.59.79.254247.59.79.2554,094
182247.59.80.0/20247.59.80.1 to 247.59.95.254247.59.95.2554,094
183247.59.96.0/20247.59.96.1 to 247.59.111.254247.59.111.2554,094
184247.59.112.0/20247.59.112.1 to 247.59.127.254247.59.127.2554,094
185247.59.128.0/20247.59.128.1 to 247.59.143.254247.59.143.2554,094
186247.59.144.0/20247.59.144.1 to 247.59.159.254247.59.159.2554,094
187247.59.160.0/20247.59.160.1 to 247.59.175.254247.59.175.2554,094
188247.59.176.0/20247.59.176.1 to 247.59.191.254247.59.191.2554,094
189247.59.192.0/20247.59.192.1 to 247.59.207.254247.59.207.2554,094
190247.59.208.0/20247.59.208.1 to 247.59.223.254247.59.223.2554,094
191247.59.224.0/20247.59.224.1 to 247.59.239.254247.59.239.2554,094
192247.59.240.0/20247.59.240.1 to 247.59.255.254247.59.255.2554,094
193247.60.0.0/20247.60.0.1 to 247.60.15.254247.60.15.2554,094
194247.60.16.0/20247.60.16.1 to 247.60.31.254247.60.31.2554,094
195247.60.32.0/20247.60.32.1 to 247.60.47.254247.60.47.2554,094
196247.60.48.0/20247.60.48.1 to 247.60.63.254247.60.63.2554,094
197247.60.64.0/20247.60.64.1 to 247.60.79.254247.60.79.2554,094
198247.60.80.0/20247.60.80.1 to 247.60.95.254247.60.95.2554,094
199247.60.96.0/20247.60.96.1 to 247.60.111.254247.60.111.2554,094
200247.60.112.0/20247.60.112.1 to 247.60.127.254247.60.127.2554,094
201247.60.128.0/20247.60.128.1 to 247.60.143.254247.60.143.2554,094
202247.60.144.0/20247.60.144.1 to 247.60.159.254247.60.159.2554,094
203247.60.160.0/20247.60.160.1 to 247.60.175.254247.60.175.2554,094
204247.60.176.0/20247.60.176.1 to 247.60.191.254247.60.191.2554,094
205247.60.192.0/20247.60.192.1 to 247.60.207.254247.60.207.2554,094
206247.60.208.0/20247.60.208.1 to 247.60.223.254247.60.223.2554,094
207247.60.224.0/20247.60.224.1 to 247.60.239.254247.60.239.2554,094
208247.60.240.0/20247.60.240.1 to 247.60.255.254247.60.255.2554,094
209247.61.0.0/20247.61.0.1 to 247.61.15.254247.61.15.2554,094
210247.61.16.0/20247.61.16.1 to 247.61.31.254247.61.31.2554,094
211247.61.32.0/20247.61.32.1 to 247.61.47.254247.61.47.2554,094
212247.61.48.0/20247.61.48.1 to 247.61.63.254247.61.63.2554,094
213247.61.64.0/20247.61.64.1 to 247.61.79.254247.61.79.2554,094
214247.61.80.0/20247.61.80.1 to 247.61.95.254247.61.95.2554,094
215247.61.96.0/20247.61.96.1 to 247.61.111.254247.61.111.2554,094
216247.61.112.0/20247.61.112.1 to 247.61.127.254247.61.127.2554,094
217247.61.128.0/20247.61.128.1 to 247.61.143.254247.61.143.2554,094
218247.61.144.0/20247.61.144.1 to 247.61.159.254247.61.159.2554,094
219247.61.160.0/20247.61.160.1 to 247.61.175.254247.61.175.2554,094
220247.61.176.0/20247.61.176.1 to 247.61.191.254247.61.191.2554,094
221247.61.192.0/20247.61.192.1 to 247.61.207.254247.61.207.2554,094
222247.61.208.0/20247.61.208.1 to 247.61.223.254247.61.223.2554,094
223247.61.224.0/20247.61.224.1 to 247.61.239.254247.61.239.2554,094
224247.61.240.0/20247.61.240.1 to 247.61.255.254247.61.255.2554,094
225247.62.0.0/20247.62.0.1 to 247.62.15.254247.62.15.2554,094
226247.62.16.0/20247.62.16.1 to 247.62.31.254247.62.31.2554,094
227247.62.32.0/20247.62.32.1 to 247.62.47.254247.62.47.2554,094
228247.62.48.0/20247.62.48.1 to 247.62.63.254247.62.63.2554,094
229247.62.64.0/20247.62.64.1 to 247.62.79.254247.62.79.2554,094
230247.62.80.0/20247.62.80.1 to 247.62.95.254247.62.95.2554,094
231247.62.96.0/20247.62.96.1 to 247.62.111.254247.62.111.2554,094
232247.62.112.0/20247.62.112.1 to 247.62.127.254247.62.127.2554,094
233247.62.128.0/20247.62.128.1 to 247.62.143.254247.62.143.2554,094
234247.62.144.0/20247.62.144.1 to 247.62.159.254247.62.159.2554,094
235247.62.160.0/20247.62.160.1 to 247.62.175.254247.62.175.2554,094
236247.62.176.0/20247.62.176.1 to 247.62.191.254247.62.191.2554,094
237247.62.192.0/20247.62.192.1 to 247.62.207.254247.62.207.2554,094
238247.62.208.0/20247.62.208.1 to 247.62.223.254247.62.223.2554,094
239247.62.224.0/20247.62.224.1 to 247.62.239.254247.62.239.2554,094
240247.62.240.0/20247.62.240.1 to 247.62.255.254247.62.255.2554,094
241247.63.0.0/20247.63.0.1 to 247.63.15.254247.63.15.2554,094
242247.63.16.0/20247.63.16.1 to 247.63.31.254247.63.31.2554,094
243247.63.32.0/20247.63.32.1 to 247.63.47.254247.63.47.2554,094
244247.63.48.0/20247.63.48.1 to 247.63.63.254247.63.63.2554,094
245247.63.64.0/20247.63.64.1 to 247.63.79.254247.63.79.2554,094
246247.63.80.0/20247.63.80.1 to 247.63.95.254247.63.95.2554,094
247247.63.96.0/20247.63.96.1 to 247.63.111.254247.63.111.2554,094
248247.63.112.0/20247.63.112.1 to 247.63.127.254247.63.127.2554,094
249247.63.128.0/20247.63.128.1 to 247.63.143.254247.63.143.2554,094
250247.63.144.0/20247.63.144.1 to 247.63.159.254247.63.159.2554,094
251247.63.160.0/20247.63.160.1 to 247.63.175.254247.63.175.2554,094
252247.63.176.0/20247.63.176.1 to 247.63.191.254247.63.191.2554,094
253247.63.192.0/20247.63.192.1 to 247.63.207.254247.63.207.2554,094
254247.63.208.0/20247.63.208.1 to 247.63.223.254247.63.223.2554,094
255247.63.224.0/20247.63.224.1 to 247.63.239.254247.63.239.2554,094
256247.63.240.0/20247.63.240.1 to 247.63.255.254247.63.255.2554,094

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.