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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.

Network124.0.0.0/9
Usable hosts8,388,606
Subnet mask255.128.0.0
Addresses8,388,608
Network address
124.0.0.0
Broadcast address
124.127.255.255
First usable
124.0.0.1
Last usable
124.127.255.254
Usable hosts
8,388,606 (8,388,608 less the network and broadcast addresses)
Subnet mask
255.128.0.0
Wildcard mask
0.127.255.255 (Cisco ACLs, OSPF)
Prefix length
/9
Type
Public public
Old class
A (default /8)
As numbers
Hex 7C000000 · Integer 2080374784 to 2088763391
Reverse DNS zones
0.124.in-addr.arpa
1.124.in-addr.arpa
2.124.in-addr.arpa
3.124.in-addr.arpa
4.124.in-addr.arpa
5.124.in-addr.arpa
6.124.in-addr.arpa
7.124.in-addr.arpa
8.124.in-addr.arpa
9.124.in-addr.arpa
10.124.in-addr.arpa
11.124.in-addr.arpa
12.124.in-addr.arpa
13.124.in-addr.arpa
14.124.in-addr.arpa
15.124.in-addr.arpa
and 112 more
/9 is not on a 8-bit boundary, so it takes 128 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01111100.00000000.00000000.00000000124.0.0.0
Subnet mask11111111.10000000.00000000.00000000255.128.0.0
Network01111100.00000000.00000000.00000000124.0.0.0
Broadcast01111100.01111111.11111111.11111111124.127.255.255
Split into smaller subnets/20
/10 (2)/11 (4)/12 (8)/13 (16)/14 (32)/15 (64)/16 (128)/17 (256)/18 (512)/19 (1,024)/20 (2,048)/21 (4,096)

124.0.0.0/9 makes 2,048 subnets of /20; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1124.0.0.0/20124.0.0.1 to 124.0.15.254124.0.15.2554,094
2124.0.16.0/20124.0.16.1 to 124.0.31.254124.0.31.2554,094
3124.0.32.0/20124.0.32.1 to 124.0.47.254124.0.47.2554,094
4124.0.48.0/20124.0.48.1 to 124.0.63.254124.0.63.2554,094
5124.0.64.0/20124.0.64.1 to 124.0.79.254124.0.79.2554,094
6124.0.80.0/20124.0.80.1 to 124.0.95.254124.0.95.2554,094
7124.0.96.0/20124.0.96.1 to 124.0.111.254124.0.111.2554,094
8124.0.112.0/20124.0.112.1 to 124.0.127.254124.0.127.2554,094
9124.0.128.0/20124.0.128.1 to 124.0.143.254124.0.143.2554,094
10124.0.144.0/20124.0.144.1 to 124.0.159.254124.0.159.2554,094
11124.0.160.0/20124.0.160.1 to 124.0.175.254124.0.175.2554,094
12124.0.176.0/20124.0.176.1 to 124.0.191.254124.0.191.2554,094
13124.0.192.0/20124.0.192.1 to 124.0.207.254124.0.207.2554,094
14124.0.208.0/20124.0.208.1 to 124.0.223.254124.0.223.2554,094
15124.0.224.0/20124.0.224.1 to 124.0.239.254124.0.239.2554,094
16124.0.240.0/20124.0.240.1 to 124.0.255.254124.0.255.2554,094
17124.1.0.0/20124.1.0.1 to 124.1.15.254124.1.15.2554,094
18124.1.16.0/20124.1.16.1 to 124.1.31.254124.1.31.2554,094
19124.1.32.0/20124.1.32.1 to 124.1.47.254124.1.47.2554,094
20124.1.48.0/20124.1.48.1 to 124.1.63.254124.1.63.2554,094
21124.1.64.0/20124.1.64.1 to 124.1.79.254124.1.79.2554,094
22124.1.80.0/20124.1.80.1 to 124.1.95.254124.1.95.2554,094
23124.1.96.0/20124.1.96.1 to 124.1.111.254124.1.111.2554,094
24124.1.112.0/20124.1.112.1 to 124.1.127.254124.1.127.2554,094
25124.1.128.0/20124.1.128.1 to 124.1.143.254124.1.143.2554,094
26124.1.144.0/20124.1.144.1 to 124.1.159.254124.1.159.2554,094
27124.1.160.0/20124.1.160.1 to 124.1.175.254124.1.175.2554,094
28124.1.176.0/20124.1.176.1 to 124.1.191.254124.1.191.2554,094
29124.1.192.0/20124.1.192.1 to 124.1.207.254124.1.207.2554,094
30124.1.208.0/20124.1.208.1 to 124.1.223.254124.1.223.2554,094
31124.1.224.0/20124.1.224.1 to 124.1.239.254124.1.239.2554,094
32124.1.240.0/20124.1.240.1 to 124.1.255.254124.1.255.2554,094
33124.2.0.0/20124.2.0.1 to 124.2.15.254124.2.15.2554,094
34124.2.16.0/20124.2.16.1 to 124.2.31.254124.2.31.2554,094
35124.2.32.0/20124.2.32.1 to 124.2.47.254124.2.47.2554,094
36124.2.48.0/20124.2.48.1 to 124.2.63.254124.2.63.2554,094
37124.2.64.0/20124.2.64.1 to 124.2.79.254124.2.79.2554,094
38124.2.80.0/20124.2.80.1 to 124.2.95.254124.2.95.2554,094
39124.2.96.0/20124.2.96.1 to 124.2.111.254124.2.111.2554,094
40124.2.112.0/20124.2.112.1 to 124.2.127.254124.2.127.2554,094
41124.2.128.0/20124.2.128.1 to 124.2.143.254124.2.143.2554,094
42124.2.144.0/20124.2.144.1 to 124.2.159.254124.2.159.2554,094
43124.2.160.0/20124.2.160.1 to 124.2.175.254124.2.175.2554,094
44124.2.176.0/20124.2.176.1 to 124.2.191.254124.2.191.2554,094
45124.2.192.0/20124.2.192.1 to 124.2.207.254124.2.207.2554,094
46124.2.208.0/20124.2.208.1 to 124.2.223.254124.2.223.2554,094
47124.2.224.0/20124.2.224.1 to 124.2.239.254124.2.239.2554,094
48124.2.240.0/20124.2.240.1 to 124.2.255.254124.2.255.2554,094
49124.3.0.0/20124.3.0.1 to 124.3.15.254124.3.15.2554,094
50124.3.16.0/20124.3.16.1 to 124.3.31.254124.3.31.2554,094
51124.3.32.0/20124.3.32.1 to 124.3.47.254124.3.47.2554,094
52124.3.48.0/20124.3.48.1 to 124.3.63.254124.3.63.2554,094
53124.3.64.0/20124.3.64.1 to 124.3.79.254124.3.79.2554,094
54124.3.80.0/20124.3.80.1 to 124.3.95.254124.3.95.2554,094
55124.3.96.0/20124.3.96.1 to 124.3.111.254124.3.111.2554,094
56124.3.112.0/20124.3.112.1 to 124.3.127.254124.3.127.2554,094
57124.3.128.0/20124.3.128.1 to 124.3.143.254124.3.143.2554,094
58124.3.144.0/20124.3.144.1 to 124.3.159.254124.3.159.2554,094
59124.3.160.0/20124.3.160.1 to 124.3.175.254124.3.175.2554,094
60124.3.176.0/20124.3.176.1 to 124.3.191.254124.3.191.2554,094
61124.3.192.0/20124.3.192.1 to 124.3.207.254124.3.207.2554,094
62124.3.208.0/20124.3.208.1 to 124.3.223.254124.3.223.2554,094
63124.3.224.0/20124.3.224.1 to 124.3.239.254124.3.239.2554,094
64124.3.240.0/20124.3.240.1 to 124.3.255.254124.3.255.2554,094
65124.4.0.0/20124.4.0.1 to 124.4.15.254124.4.15.2554,094
66124.4.16.0/20124.4.16.1 to 124.4.31.254124.4.31.2554,094
67124.4.32.0/20124.4.32.1 to 124.4.47.254124.4.47.2554,094
68124.4.48.0/20124.4.48.1 to 124.4.63.254124.4.63.2554,094
69124.4.64.0/20124.4.64.1 to 124.4.79.254124.4.79.2554,094
70124.4.80.0/20124.4.80.1 to 124.4.95.254124.4.95.2554,094
71124.4.96.0/20124.4.96.1 to 124.4.111.254124.4.111.2554,094
72124.4.112.0/20124.4.112.1 to 124.4.127.254124.4.127.2554,094
73124.4.128.0/20124.4.128.1 to 124.4.143.254124.4.143.2554,094
74124.4.144.0/20124.4.144.1 to 124.4.159.254124.4.159.2554,094
75124.4.160.0/20124.4.160.1 to 124.4.175.254124.4.175.2554,094
76124.4.176.0/20124.4.176.1 to 124.4.191.254124.4.191.2554,094
77124.4.192.0/20124.4.192.1 to 124.4.207.254124.4.207.2554,094
78124.4.208.0/20124.4.208.1 to 124.4.223.254124.4.223.2554,094
79124.4.224.0/20124.4.224.1 to 124.4.239.254124.4.239.2554,094
80124.4.240.0/20124.4.240.1 to 124.4.255.254124.4.255.2554,094
81124.5.0.0/20124.5.0.1 to 124.5.15.254124.5.15.2554,094
82124.5.16.0/20124.5.16.1 to 124.5.31.254124.5.31.2554,094
83124.5.32.0/20124.5.32.1 to 124.5.47.254124.5.47.2554,094
84124.5.48.0/20124.5.48.1 to 124.5.63.254124.5.63.2554,094
85124.5.64.0/20124.5.64.1 to 124.5.79.254124.5.79.2554,094
86124.5.80.0/20124.5.80.1 to 124.5.95.254124.5.95.2554,094
87124.5.96.0/20124.5.96.1 to 124.5.111.254124.5.111.2554,094
88124.5.112.0/20124.5.112.1 to 124.5.127.254124.5.127.2554,094
89124.5.128.0/20124.5.128.1 to 124.5.143.254124.5.143.2554,094
90124.5.144.0/20124.5.144.1 to 124.5.159.254124.5.159.2554,094
91124.5.160.0/20124.5.160.1 to 124.5.175.254124.5.175.2554,094
92124.5.176.0/20124.5.176.1 to 124.5.191.254124.5.191.2554,094
93124.5.192.0/20124.5.192.1 to 124.5.207.254124.5.207.2554,094
94124.5.208.0/20124.5.208.1 to 124.5.223.254124.5.223.2554,094
95124.5.224.0/20124.5.224.1 to 124.5.239.254124.5.239.2554,094
96124.5.240.0/20124.5.240.1 to 124.5.255.254124.5.255.2554,094
97124.6.0.0/20124.6.0.1 to 124.6.15.254124.6.15.2554,094
98124.6.16.0/20124.6.16.1 to 124.6.31.254124.6.31.2554,094
99124.6.32.0/20124.6.32.1 to 124.6.47.254124.6.47.2554,094
100124.6.48.0/20124.6.48.1 to 124.6.63.254124.6.63.2554,094
101124.6.64.0/20124.6.64.1 to 124.6.79.254124.6.79.2554,094
102124.6.80.0/20124.6.80.1 to 124.6.95.254124.6.95.2554,094
103124.6.96.0/20124.6.96.1 to 124.6.111.254124.6.111.2554,094
104124.6.112.0/20124.6.112.1 to 124.6.127.254124.6.127.2554,094
105124.6.128.0/20124.6.128.1 to 124.6.143.254124.6.143.2554,094
106124.6.144.0/20124.6.144.1 to 124.6.159.254124.6.159.2554,094
107124.6.160.0/20124.6.160.1 to 124.6.175.254124.6.175.2554,094
108124.6.176.0/20124.6.176.1 to 124.6.191.254124.6.191.2554,094
109124.6.192.0/20124.6.192.1 to 124.6.207.254124.6.207.2554,094
110124.6.208.0/20124.6.208.1 to 124.6.223.254124.6.223.2554,094
111124.6.224.0/20124.6.224.1 to 124.6.239.254124.6.239.2554,094
112124.6.240.0/20124.6.240.1 to 124.6.255.254124.6.255.2554,094
113124.7.0.0/20124.7.0.1 to 124.7.15.254124.7.15.2554,094
114124.7.16.0/20124.7.16.1 to 124.7.31.254124.7.31.2554,094
115124.7.32.0/20124.7.32.1 to 124.7.47.254124.7.47.2554,094
116124.7.48.0/20124.7.48.1 to 124.7.63.254124.7.63.2554,094
117124.7.64.0/20124.7.64.1 to 124.7.79.254124.7.79.2554,094
118124.7.80.0/20124.7.80.1 to 124.7.95.254124.7.95.2554,094
119124.7.96.0/20124.7.96.1 to 124.7.111.254124.7.111.2554,094
120124.7.112.0/20124.7.112.1 to 124.7.127.254124.7.127.2554,094
121124.7.128.0/20124.7.128.1 to 124.7.143.254124.7.143.2554,094
122124.7.144.0/20124.7.144.1 to 124.7.159.254124.7.159.2554,094
123124.7.160.0/20124.7.160.1 to 124.7.175.254124.7.175.2554,094
124124.7.176.0/20124.7.176.1 to 124.7.191.254124.7.191.2554,094
125124.7.192.0/20124.7.192.1 to 124.7.207.254124.7.207.2554,094
126124.7.208.0/20124.7.208.1 to 124.7.223.254124.7.223.2554,094
127124.7.224.0/20124.7.224.1 to 124.7.239.254124.7.239.2554,094
128124.7.240.0/20124.7.240.1 to 124.7.255.254124.7.255.2554,094
129124.8.0.0/20124.8.0.1 to 124.8.15.254124.8.15.2554,094
130124.8.16.0/20124.8.16.1 to 124.8.31.254124.8.31.2554,094
131124.8.32.0/20124.8.32.1 to 124.8.47.254124.8.47.2554,094
132124.8.48.0/20124.8.48.1 to 124.8.63.254124.8.63.2554,094
133124.8.64.0/20124.8.64.1 to 124.8.79.254124.8.79.2554,094
134124.8.80.0/20124.8.80.1 to 124.8.95.254124.8.95.2554,094
135124.8.96.0/20124.8.96.1 to 124.8.111.254124.8.111.2554,094
136124.8.112.0/20124.8.112.1 to 124.8.127.254124.8.127.2554,094
137124.8.128.0/20124.8.128.1 to 124.8.143.254124.8.143.2554,094
138124.8.144.0/20124.8.144.1 to 124.8.159.254124.8.159.2554,094
139124.8.160.0/20124.8.160.1 to 124.8.175.254124.8.175.2554,094
140124.8.176.0/20124.8.176.1 to 124.8.191.254124.8.191.2554,094
141124.8.192.0/20124.8.192.1 to 124.8.207.254124.8.207.2554,094
142124.8.208.0/20124.8.208.1 to 124.8.223.254124.8.223.2554,094
143124.8.224.0/20124.8.224.1 to 124.8.239.254124.8.239.2554,094
144124.8.240.0/20124.8.240.1 to 124.8.255.254124.8.255.2554,094
145124.9.0.0/20124.9.0.1 to 124.9.15.254124.9.15.2554,094
146124.9.16.0/20124.9.16.1 to 124.9.31.254124.9.31.2554,094
147124.9.32.0/20124.9.32.1 to 124.9.47.254124.9.47.2554,094
148124.9.48.0/20124.9.48.1 to 124.9.63.254124.9.63.2554,094
149124.9.64.0/20124.9.64.1 to 124.9.79.254124.9.79.2554,094
150124.9.80.0/20124.9.80.1 to 124.9.95.254124.9.95.2554,094
151124.9.96.0/20124.9.96.1 to 124.9.111.254124.9.111.2554,094
152124.9.112.0/20124.9.112.1 to 124.9.127.254124.9.127.2554,094
153124.9.128.0/20124.9.128.1 to 124.9.143.254124.9.143.2554,094
154124.9.144.0/20124.9.144.1 to 124.9.159.254124.9.159.2554,094
155124.9.160.0/20124.9.160.1 to 124.9.175.254124.9.175.2554,094
156124.9.176.0/20124.9.176.1 to 124.9.191.254124.9.191.2554,094
157124.9.192.0/20124.9.192.1 to 124.9.207.254124.9.207.2554,094
158124.9.208.0/20124.9.208.1 to 124.9.223.254124.9.223.2554,094
159124.9.224.0/20124.9.224.1 to 124.9.239.254124.9.239.2554,094
160124.9.240.0/20124.9.240.1 to 124.9.255.254124.9.255.2554,094
161124.10.0.0/20124.10.0.1 to 124.10.15.254124.10.15.2554,094
162124.10.16.0/20124.10.16.1 to 124.10.31.254124.10.31.2554,094
163124.10.32.0/20124.10.32.1 to 124.10.47.254124.10.47.2554,094
164124.10.48.0/20124.10.48.1 to 124.10.63.254124.10.63.2554,094
165124.10.64.0/20124.10.64.1 to 124.10.79.254124.10.79.2554,094
166124.10.80.0/20124.10.80.1 to 124.10.95.254124.10.95.2554,094
167124.10.96.0/20124.10.96.1 to 124.10.111.254124.10.111.2554,094
168124.10.112.0/20124.10.112.1 to 124.10.127.254124.10.127.2554,094
169124.10.128.0/20124.10.128.1 to 124.10.143.254124.10.143.2554,094
170124.10.144.0/20124.10.144.1 to 124.10.159.254124.10.159.2554,094
171124.10.160.0/20124.10.160.1 to 124.10.175.254124.10.175.2554,094
172124.10.176.0/20124.10.176.1 to 124.10.191.254124.10.191.2554,094
173124.10.192.0/20124.10.192.1 to 124.10.207.254124.10.207.2554,094
174124.10.208.0/20124.10.208.1 to 124.10.223.254124.10.223.2554,094
175124.10.224.0/20124.10.224.1 to 124.10.239.254124.10.239.2554,094
176124.10.240.0/20124.10.240.1 to 124.10.255.254124.10.255.2554,094
177124.11.0.0/20124.11.0.1 to 124.11.15.254124.11.15.2554,094
178124.11.16.0/20124.11.16.1 to 124.11.31.254124.11.31.2554,094
179124.11.32.0/20124.11.32.1 to 124.11.47.254124.11.47.2554,094
180124.11.48.0/20124.11.48.1 to 124.11.63.254124.11.63.2554,094
181124.11.64.0/20124.11.64.1 to 124.11.79.254124.11.79.2554,094
182124.11.80.0/20124.11.80.1 to 124.11.95.254124.11.95.2554,094
183124.11.96.0/20124.11.96.1 to 124.11.111.254124.11.111.2554,094
184124.11.112.0/20124.11.112.1 to 124.11.127.254124.11.127.2554,094
185124.11.128.0/20124.11.128.1 to 124.11.143.254124.11.143.2554,094
186124.11.144.0/20124.11.144.1 to 124.11.159.254124.11.159.2554,094
187124.11.160.0/20124.11.160.1 to 124.11.175.254124.11.175.2554,094
188124.11.176.0/20124.11.176.1 to 124.11.191.254124.11.191.2554,094
189124.11.192.0/20124.11.192.1 to 124.11.207.254124.11.207.2554,094
190124.11.208.0/20124.11.208.1 to 124.11.223.254124.11.223.2554,094
191124.11.224.0/20124.11.224.1 to 124.11.239.254124.11.239.2554,094
192124.11.240.0/20124.11.240.1 to 124.11.255.254124.11.255.2554,094
193124.12.0.0/20124.12.0.1 to 124.12.15.254124.12.15.2554,094
194124.12.16.0/20124.12.16.1 to 124.12.31.254124.12.31.2554,094
195124.12.32.0/20124.12.32.1 to 124.12.47.254124.12.47.2554,094
196124.12.48.0/20124.12.48.1 to 124.12.63.254124.12.63.2554,094
197124.12.64.0/20124.12.64.1 to 124.12.79.254124.12.79.2554,094
198124.12.80.0/20124.12.80.1 to 124.12.95.254124.12.95.2554,094
199124.12.96.0/20124.12.96.1 to 124.12.111.254124.12.111.2554,094
200124.12.112.0/20124.12.112.1 to 124.12.127.254124.12.127.2554,094
201124.12.128.0/20124.12.128.1 to 124.12.143.254124.12.143.2554,094
202124.12.144.0/20124.12.144.1 to 124.12.159.254124.12.159.2554,094
203124.12.160.0/20124.12.160.1 to 124.12.175.254124.12.175.2554,094
204124.12.176.0/20124.12.176.1 to 124.12.191.254124.12.191.2554,094
205124.12.192.0/20124.12.192.1 to 124.12.207.254124.12.207.2554,094
206124.12.208.0/20124.12.208.1 to 124.12.223.254124.12.223.2554,094
207124.12.224.0/20124.12.224.1 to 124.12.239.254124.12.239.2554,094
208124.12.240.0/20124.12.240.1 to 124.12.255.254124.12.255.2554,094
209124.13.0.0/20124.13.0.1 to 124.13.15.254124.13.15.2554,094
210124.13.16.0/20124.13.16.1 to 124.13.31.254124.13.31.2554,094
211124.13.32.0/20124.13.32.1 to 124.13.47.254124.13.47.2554,094
212124.13.48.0/20124.13.48.1 to 124.13.63.254124.13.63.2554,094
213124.13.64.0/20124.13.64.1 to 124.13.79.254124.13.79.2554,094
214124.13.80.0/20124.13.80.1 to 124.13.95.254124.13.95.2554,094
215124.13.96.0/20124.13.96.1 to 124.13.111.254124.13.111.2554,094
216124.13.112.0/20124.13.112.1 to 124.13.127.254124.13.127.2554,094
217124.13.128.0/20124.13.128.1 to 124.13.143.254124.13.143.2554,094
218124.13.144.0/20124.13.144.1 to 124.13.159.254124.13.159.2554,094
219124.13.160.0/20124.13.160.1 to 124.13.175.254124.13.175.2554,094
220124.13.176.0/20124.13.176.1 to 124.13.191.254124.13.191.2554,094
221124.13.192.0/20124.13.192.1 to 124.13.207.254124.13.207.2554,094
222124.13.208.0/20124.13.208.1 to 124.13.223.254124.13.223.2554,094
223124.13.224.0/20124.13.224.1 to 124.13.239.254124.13.239.2554,094
224124.13.240.0/20124.13.240.1 to 124.13.255.254124.13.255.2554,094
225124.14.0.0/20124.14.0.1 to 124.14.15.254124.14.15.2554,094
226124.14.16.0/20124.14.16.1 to 124.14.31.254124.14.31.2554,094
227124.14.32.0/20124.14.32.1 to 124.14.47.254124.14.47.2554,094
228124.14.48.0/20124.14.48.1 to 124.14.63.254124.14.63.2554,094
229124.14.64.0/20124.14.64.1 to 124.14.79.254124.14.79.2554,094
230124.14.80.0/20124.14.80.1 to 124.14.95.254124.14.95.2554,094
231124.14.96.0/20124.14.96.1 to 124.14.111.254124.14.111.2554,094
232124.14.112.0/20124.14.112.1 to 124.14.127.254124.14.127.2554,094
233124.14.128.0/20124.14.128.1 to 124.14.143.254124.14.143.2554,094
234124.14.144.0/20124.14.144.1 to 124.14.159.254124.14.159.2554,094
235124.14.160.0/20124.14.160.1 to 124.14.175.254124.14.175.2554,094
236124.14.176.0/20124.14.176.1 to 124.14.191.254124.14.191.2554,094
237124.14.192.0/20124.14.192.1 to 124.14.207.254124.14.207.2554,094
238124.14.208.0/20124.14.208.1 to 124.14.223.254124.14.223.2554,094
239124.14.224.0/20124.14.224.1 to 124.14.239.254124.14.239.2554,094
240124.14.240.0/20124.14.240.1 to 124.14.255.254124.14.255.2554,094
241124.15.0.0/20124.15.0.1 to 124.15.15.254124.15.15.2554,094
242124.15.16.0/20124.15.16.1 to 124.15.31.254124.15.31.2554,094
243124.15.32.0/20124.15.32.1 to 124.15.47.254124.15.47.2554,094
244124.15.48.0/20124.15.48.1 to 124.15.63.254124.15.63.2554,094
245124.15.64.0/20124.15.64.1 to 124.15.79.254124.15.79.2554,094
246124.15.80.0/20124.15.80.1 to 124.15.95.254124.15.95.2554,094
247124.15.96.0/20124.15.96.1 to 124.15.111.254124.15.111.2554,094
248124.15.112.0/20124.15.112.1 to 124.15.127.254124.15.127.2554,094
249124.15.128.0/20124.15.128.1 to 124.15.143.254124.15.143.2554,094
250124.15.144.0/20124.15.144.1 to 124.15.159.254124.15.159.2554,094
251124.15.160.0/20124.15.160.1 to 124.15.175.254124.15.175.2554,094
252124.15.176.0/20124.15.176.1 to 124.15.191.254124.15.191.2554,094
253124.15.192.0/20124.15.192.1 to 124.15.207.254124.15.207.2554,094
254124.15.208.0/20124.15.208.1 to 124.15.223.254124.15.223.2554,094
255124.15.224.0/20124.15.224.1 to 124.15.239.254124.15.239.2554,094
256124.15.240.0/20124.15.240.1 to 124.15.255.254124.15.255.2554,094

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.