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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.

Network125.128.0.0/9
Usable hosts8,388,606
Subnet mask255.128.0.0
Addresses8,388,608
Network address
125.128.0.0
Broadcast address
125.255.255.255
First usable
125.128.0.1
Last usable
125.255.255.254
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 7D800000 · Integer 2105540608 to 2113929215
Reverse DNS zones
128.125.in-addr.arpa
129.125.in-addr.arpa
130.125.in-addr.arpa
131.125.in-addr.arpa
132.125.in-addr.arpa
133.125.in-addr.arpa
134.125.in-addr.arpa
135.125.in-addr.arpa
136.125.in-addr.arpa
137.125.in-addr.arpa
138.125.in-addr.arpa
139.125.in-addr.arpa
140.125.in-addr.arpa
141.125.in-addr.arpa
142.125.in-addr.arpa
143.125.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
Address01111101.10000000.00000000.00000000125.128.0.0
Subnet mask11111111.10000000.00000000.00000000255.128.0.0
Network01111101.10000000.00000000.00000000125.128.0.0
Broadcast01111101.11111111.11111111.11111111125.255.255.255
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)

125.128.0.0/9 makes 2,048 subnets of /20; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1125.128.0.0/20125.128.0.1 to 125.128.15.254125.128.15.2554,094
2125.128.16.0/20125.128.16.1 to 125.128.31.254125.128.31.2554,094
3125.128.32.0/20125.128.32.1 to 125.128.47.254125.128.47.2554,094
4125.128.48.0/20125.128.48.1 to 125.128.63.254125.128.63.2554,094
5125.128.64.0/20125.128.64.1 to 125.128.79.254125.128.79.2554,094
6125.128.80.0/20125.128.80.1 to 125.128.95.254125.128.95.2554,094
7125.128.96.0/20125.128.96.1 to 125.128.111.254125.128.111.2554,094
8125.128.112.0/20125.128.112.1 to 125.128.127.254125.128.127.2554,094
9125.128.128.0/20125.128.128.1 to 125.128.143.254125.128.143.2554,094
10125.128.144.0/20125.128.144.1 to 125.128.159.254125.128.159.2554,094
11125.128.160.0/20125.128.160.1 to 125.128.175.254125.128.175.2554,094
12125.128.176.0/20125.128.176.1 to 125.128.191.254125.128.191.2554,094
13125.128.192.0/20125.128.192.1 to 125.128.207.254125.128.207.2554,094
14125.128.208.0/20125.128.208.1 to 125.128.223.254125.128.223.2554,094
15125.128.224.0/20125.128.224.1 to 125.128.239.254125.128.239.2554,094
16125.128.240.0/20125.128.240.1 to 125.128.255.254125.128.255.2554,094
17125.129.0.0/20125.129.0.1 to 125.129.15.254125.129.15.2554,094
18125.129.16.0/20125.129.16.1 to 125.129.31.254125.129.31.2554,094
19125.129.32.0/20125.129.32.1 to 125.129.47.254125.129.47.2554,094
20125.129.48.0/20125.129.48.1 to 125.129.63.254125.129.63.2554,094
21125.129.64.0/20125.129.64.1 to 125.129.79.254125.129.79.2554,094
22125.129.80.0/20125.129.80.1 to 125.129.95.254125.129.95.2554,094
23125.129.96.0/20125.129.96.1 to 125.129.111.254125.129.111.2554,094
24125.129.112.0/20125.129.112.1 to 125.129.127.254125.129.127.2554,094
25125.129.128.0/20125.129.128.1 to 125.129.143.254125.129.143.2554,094
26125.129.144.0/20125.129.144.1 to 125.129.159.254125.129.159.2554,094
27125.129.160.0/20125.129.160.1 to 125.129.175.254125.129.175.2554,094
28125.129.176.0/20125.129.176.1 to 125.129.191.254125.129.191.2554,094
29125.129.192.0/20125.129.192.1 to 125.129.207.254125.129.207.2554,094
30125.129.208.0/20125.129.208.1 to 125.129.223.254125.129.223.2554,094
31125.129.224.0/20125.129.224.1 to 125.129.239.254125.129.239.2554,094
32125.129.240.0/20125.129.240.1 to 125.129.255.254125.129.255.2554,094
33125.130.0.0/20125.130.0.1 to 125.130.15.254125.130.15.2554,094
34125.130.16.0/20125.130.16.1 to 125.130.31.254125.130.31.2554,094
35125.130.32.0/20125.130.32.1 to 125.130.47.254125.130.47.2554,094
36125.130.48.0/20125.130.48.1 to 125.130.63.254125.130.63.2554,094
37125.130.64.0/20125.130.64.1 to 125.130.79.254125.130.79.2554,094
38125.130.80.0/20125.130.80.1 to 125.130.95.254125.130.95.2554,094
39125.130.96.0/20125.130.96.1 to 125.130.111.254125.130.111.2554,094
40125.130.112.0/20125.130.112.1 to 125.130.127.254125.130.127.2554,094
41125.130.128.0/20125.130.128.1 to 125.130.143.254125.130.143.2554,094
42125.130.144.0/20125.130.144.1 to 125.130.159.254125.130.159.2554,094
43125.130.160.0/20125.130.160.1 to 125.130.175.254125.130.175.2554,094
44125.130.176.0/20125.130.176.1 to 125.130.191.254125.130.191.2554,094
45125.130.192.0/20125.130.192.1 to 125.130.207.254125.130.207.2554,094
46125.130.208.0/20125.130.208.1 to 125.130.223.254125.130.223.2554,094
47125.130.224.0/20125.130.224.1 to 125.130.239.254125.130.239.2554,094
48125.130.240.0/20125.130.240.1 to 125.130.255.254125.130.255.2554,094
49125.131.0.0/20125.131.0.1 to 125.131.15.254125.131.15.2554,094
50125.131.16.0/20125.131.16.1 to 125.131.31.254125.131.31.2554,094
51125.131.32.0/20125.131.32.1 to 125.131.47.254125.131.47.2554,094
52125.131.48.0/20125.131.48.1 to 125.131.63.254125.131.63.2554,094
53125.131.64.0/20125.131.64.1 to 125.131.79.254125.131.79.2554,094
54125.131.80.0/20125.131.80.1 to 125.131.95.254125.131.95.2554,094
55125.131.96.0/20125.131.96.1 to 125.131.111.254125.131.111.2554,094
56125.131.112.0/20125.131.112.1 to 125.131.127.254125.131.127.2554,094
57125.131.128.0/20125.131.128.1 to 125.131.143.254125.131.143.2554,094
58125.131.144.0/20125.131.144.1 to 125.131.159.254125.131.159.2554,094
59125.131.160.0/20125.131.160.1 to 125.131.175.254125.131.175.2554,094
60125.131.176.0/20125.131.176.1 to 125.131.191.254125.131.191.2554,094
61125.131.192.0/20125.131.192.1 to 125.131.207.254125.131.207.2554,094
62125.131.208.0/20125.131.208.1 to 125.131.223.254125.131.223.2554,094
63125.131.224.0/20125.131.224.1 to 125.131.239.254125.131.239.2554,094
64125.131.240.0/20125.131.240.1 to 125.131.255.254125.131.255.2554,094
65125.132.0.0/20125.132.0.1 to 125.132.15.254125.132.15.2554,094
66125.132.16.0/20125.132.16.1 to 125.132.31.254125.132.31.2554,094
67125.132.32.0/20125.132.32.1 to 125.132.47.254125.132.47.2554,094
68125.132.48.0/20125.132.48.1 to 125.132.63.254125.132.63.2554,094
69125.132.64.0/20125.132.64.1 to 125.132.79.254125.132.79.2554,094
70125.132.80.0/20125.132.80.1 to 125.132.95.254125.132.95.2554,094
71125.132.96.0/20125.132.96.1 to 125.132.111.254125.132.111.2554,094
72125.132.112.0/20125.132.112.1 to 125.132.127.254125.132.127.2554,094
73125.132.128.0/20125.132.128.1 to 125.132.143.254125.132.143.2554,094
74125.132.144.0/20125.132.144.1 to 125.132.159.254125.132.159.2554,094
75125.132.160.0/20125.132.160.1 to 125.132.175.254125.132.175.2554,094
76125.132.176.0/20125.132.176.1 to 125.132.191.254125.132.191.2554,094
77125.132.192.0/20125.132.192.1 to 125.132.207.254125.132.207.2554,094
78125.132.208.0/20125.132.208.1 to 125.132.223.254125.132.223.2554,094
79125.132.224.0/20125.132.224.1 to 125.132.239.254125.132.239.2554,094
80125.132.240.0/20125.132.240.1 to 125.132.255.254125.132.255.2554,094
81125.133.0.0/20125.133.0.1 to 125.133.15.254125.133.15.2554,094
82125.133.16.0/20125.133.16.1 to 125.133.31.254125.133.31.2554,094
83125.133.32.0/20125.133.32.1 to 125.133.47.254125.133.47.2554,094
84125.133.48.0/20125.133.48.1 to 125.133.63.254125.133.63.2554,094
85125.133.64.0/20125.133.64.1 to 125.133.79.254125.133.79.2554,094
86125.133.80.0/20125.133.80.1 to 125.133.95.254125.133.95.2554,094
87125.133.96.0/20125.133.96.1 to 125.133.111.254125.133.111.2554,094
88125.133.112.0/20125.133.112.1 to 125.133.127.254125.133.127.2554,094
89125.133.128.0/20125.133.128.1 to 125.133.143.254125.133.143.2554,094
90125.133.144.0/20125.133.144.1 to 125.133.159.254125.133.159.2554,094
91125.133.160.0/20125.133.160.1 to 125.133.175.254125.133.175.2554,094
92125.133.176.0/20125.133.176.1 to 125.133.191.254125.133.191.2554,094
93125.133.192.0/20125.133.192.1 to 125.133.207.254125.133.207.2554,094
94125.133.208.0/20125.133.208.1 to 125.133.223.254125.133.223.2554,094
95125.133.224.0/20125.133.224.1 to 125.133.239.254125.133.239.2554,094
96125.133.240.0/20125.133.240.1 to 125.133.255.254125.133.255.2554,094
97125.134.0.0/20125.134.0.1 to 125.134.15.254125.134.15.2554,094
98125.134.16.0/20125.134.16.1 to 125.134.31.254125.134.31.2554,094
99125.134.32.0/20125.134.32.1 to 125.134.47.254125.134.47.2554,094
100125.134.48.0/20125.134.48.1 to 125.134.63.254125.134.63.2554,094
101125.134.64.0/20125.134.64.1 to 125.134.79.254125.134.79.2554,094
102125.134.80.0/20125.134.80.1 to 125.134.95.254125.134.95.2554,094
103125.134.96.0/20125.134.96.1 to 125.134.111.254125.134.111.2554,094
104125.134.112.0/20125.134.112.1 to 125.134.127.254125.134.127.2554,094
105125.134.128.0/20125.134.128.1 to 125.134.143.254125.134.143.2554,094
106125.134.144.0/20125.134.144.1 to 125.134.159.254125.134.159.2554,094
107125.134.160.0/20125.134.160.1 to 125.134.175.254125.134.175.2554,094
108125.134.176.0/20125.134.176.1 to 125.134.191.254125.134.191.2554,094
109125.134.192.0/20125.134.192.1 to 125.134.207.254125.134.207.2554,094
110125.134.208.0/20125.134.208.1 to 125.134.223.254125.134.223.2554,094
111125.134.224.0/20125.134.224.1 to 125.134.239.254125.134.239.2554,094
112125.134.240.0/20125.134.240.1 to 125.134.255.254125.134.255.2554,094
113125.135.0.0/20125.135.0.1 to 125.135.15.254125.135.15.2554,094
114125.135.16.0/20125.135.16.1 to 125.135.31.254125.135.31.2554,094
115125.135.32.0/20125.135.32.1 to 125.135.47.254125.135.47.2554,094
116125.135.48.0/20125.135.48.1 to 125.135.63.254125.135.63.2554,094
117125.135.64.0/20125.135.64.1 to 125.135.79.254125.135.79.2554,094
118125.135.80.0/20125.135.80.1 to 125.135.95.254125.135.95.2554,094
119125.135.96.0/20125.135.96.1 to 125.135.111.254125.135.111.2554,094
120125.135.112.0/20125.135.112.1 to 125.135.127.254125.135.127.2554,094
121125.135.128.0/20125.135.128.1 to 125.135.143.254125.135.143.2554,094
122125.135.144.0/20125.135.144.1 to 125.135.159.254125.135.159.2554,094
123125.135.160.0/20125.135.160.1 to 125.135.175.254125.135.175.2554,094
124125.135.176.0/20125.135.176.1 to 125.135.191.254125.135.191.2554,094
125125.135.192.0/20125.135.192.1 to 125.135.207.254125.135.207.2554,094
126125.135.208.0/20125.135.208.1 to 125.135.223.254125.135.223.2554,094
127125.135.224.0/20125.135.224.1 to 125.135.239.254125.135.239.2554,094
128125.135.240.0/20125.135.240.1 to 125.135.255.254125.135.255.2554,094
129125.136.0.0/20125.136.0.1 to 125.136.15.254125.136.15.2554,094
130125.136.16.0/20125.136.16.1 to 125.136.31.254125.136.31.2554,094
131125.136.32.0/20125.136.32.1 to 125.136.47.254125.136.47.2554,094
132125.136.48.0/20125.136.48.1 to 125.136.63.254125.136.63.2554,094
133125.136.64.0/20125.136.64.1 to 125.136.79.254125.136.79.2554,094
134125.136.80.0/20125.136.80.1 to 125.136.95.254125.136.95.2554,094
135125.136.96.0/20125.136.96.1 to 125.136.111.254125.136.111.2554,094
136125.136.112.0/20125.136.112.1 to 125.136.127.254125.136.127.2554,094
137125.136.128.0/20125.136.128.1 to 125.136.143.254125.136.143.2554,094
138125.136.144.0/20125.136.144.1 to 125.136.159.254125.136.159.2554,094
139125.136.160.0/20125.136.160.1 to 125.136.175.254125.136.175.2554,094
140125.136.176.0/20125.136.176.1 to 125.136.191.254125.136.191.2554,094
141125.136.192.0/20125.136.192.1 to 125.136.207.254125.136.207.2554,094
142125.136.208.0/20125.136.208.1 to 125.136.223.254125.136.223.2554,094
143125.136.224.0/20125.136.224.1 to 125.136.239.254125.136.239.2554,094
144125.136.240.0/20125.136.240.1 to 125.136.255.254125.136.255.2554,094
145125.137.0.0/20125.137.0.1 to 125.137.15.254125.137.15.2554,094
146125.137.16.0/20125.137.16.1 to 125.137.31.254125.137.31.2554,094
147125.137.32.0/20125.137.32.1 to 125.137.47.254125.137.47.2554,094
148125.137.48.0/20125.137.48.1 to 125.137.63.254125.137.63.2554,094
149125.137.64.0/20125.137.64.1 to 125.137.79.254125.137.79.2554,094
150125.137.80.0/20125.137.80.1 to 125.137.95.254125.137.95.2554,094
151125.137.96.0/20125.137.96.1 to 125.137.111.254125.137.111.2554,094
152125.137.112.0/20125.137.112.1 to 125.137.127.254125.137.127.2554,094
153125.137.128.0/20125.137.128.1 to 125.137.143.254125.137.143.2554,094
154125.137.144.0/20125.137.144.1 to 125.137.159.254125.137.159.2554,094
155125.137.160.0/20125.137.160.1 to 125.137.175.254125.137.175.2554,094
156125.137.176.0/20125.137.176.1 to 125.137.191.254125.137.191.2554,094
157125.137.192.0/20125.137.192.1 to 125.137.207.254125.137.207.2554,094
158125.137.208.0/20125.137.208.1 to 125.137.223.254125.137.223.2554,094
159125.137.224.0/20125.137.224.1 to 125.137.239.254125.137.239.2554,094
160125.137.240.0/20125.137.240.1 to 125.137.255.254125.137.255.2554,094
161125.138.0.0/20125.138.0.1 to 125.138.15.254125.138.15.2554,094
162125.138.16.0/20125.138.16.1 to 125.138.31.254125.138.31.2554,094
163125.138.32.0/20125.138.32.1 to 125.138.47.254125.138.47.2554,094
164125.138.48.0/20125.138.48.1 to 125.138.63.254125.138.63.2554,094
165125.138.64.0/20125.138.64.1 to 125.138.79.254125.138.79.2554,094
166125.138.80.0/20125.138.80.1 to 125.138.95.254125.138.95.2554,094
167125.138.96.0/20125.138.96.1 to 125.138.111.254125.138.111.2554,094
168125.138.112.0/20125.138.112.1 to 125.138.127.254125.138.127.2554,094
169125.138.128.0/20125.138.128.1 to 125.138.143.254125.138.143.2554,094
170125.138.144.0/20125.138.144.1 to 125.138.159.254125.138.159.2554,094
171125.138.160.0/20125.138.160.1 to 125.138.175.254125.138.175.2554,094
172125.138.176.0/20125.138.176.1 to 125.138.191.254125.138.191.2554,094
173125.138.192.0/20125.138.192.1 to 125.138.207.254125.138.207.2554,094
174125.138.208.0/20125.138.208.1 to 125.138.223.254125.138.223.2554,094
175125.138.224.0/20125.138.224.1 to 125.138.239.254125.138.239.2554,094
176125.138.240.0/20125.138.240.1 to 125.138.255.254125.138.255.2554,094
177125.139.0.0/20125.139.0.1 to 125.139.15.254125.139.15.2554,094
178125.139.16.0/20125.139.16.1 to 125.139.31.254125.139.31.2554,094
179125.139.32.0/20125.139.32.1 to 125.139.47.254125.139.47.2554,094
180125.139.48.0/20125.139.48.1 to 125.139.63.254125.139.63.2554,094
181125.139.64.0/20125.139.64.1 to 125.139.79.254125.139.79.2554,094
182125.139.80.0/20125.139.80.1 to 125.139.95.254125.139.95.2554,094
183125.139.96.0/20125.139.96.1 to 125.139.111.254125.139.111.2554,094
184125.139.112.0/20125.139.112.1 to 125.139.127.254125.139.127.2554,094
185125.139.128.0/20125.139.128.1 to 125.139.143.254125.139.143.2554,094
186125.139.144.0/20125.139.144.1 to 125.139.159.254125.139.159.2554,094
187125.139.160.0/20125.139.160.1 to 125.139.175.254125.139.175.2554,094
188125.139.176.0/20125.139.176.1 to 125.139.191.254125.139.191.2554,094
189125.139.192.0/20125.139.192.1 to 125.139.207.254125.139.207.2554,094
190125.139.208.0/20125.139.208.1 to 125.139.223.254125.139.223.2554,094
191125.139.224.0/20125.139.224.1 to 125.139.239.254125.139.239.2554,094
192125.139.240.0/20125.139.240.1 to 125.139.255.254125.139.255.2554,094
193125.140.0.0/20125.140.0.1 to 125.140.15.254125.140.15.2554,094
194125.140.16.0/20125.140.16.1 to 125.140.31.254125.140.31.2554,094
195125.140.32.0/20125.140.32.1 to 125.140.47.254125.140.47.2554,094
196125.140.48.0/20125.140.48.1 to 125.140.63.254125.140.63.2554,094
197125.140.64.0/20125.140.64.1 to 125.140.79.254125.140.79.2554,094
198125.140.80.0/20125.140.80.1 to 125.140.95.254125.140.95.2554,094
199125.140.96.0/20125.140.96.1 to 125.140.111.254125.140.111.2554,094
200125.140.112.0/20125.140.112.1 to 125.140.127.254125.140.127.2554,094
201125.140.128.0/20125.140.128.1 to 125.140.143.254125.140.143.2554,094
202125.140.144.0/20125.140.144.1 to 125.140.159.254125.140.159.2554,094
203125.140.160.0/20125.140.160.1 to 125.140.175.254125.140.175.2554,094
204125.140.176.0/20125.140.176.1 to 125.140.191.254125.140.191.2554,094
205125.140.192.0/20125.140.192.1 to 125.140.207.254125.140.207.2554,094
206125.140.208.0/20125.140.208.1 to 125.140.223.254125.140.223.2554,094
207125.140.224.0/20125.140.224.1 to 125.140.239.254125.140.239.2554,094
208125.140.240.0/20125.140.240.1 to 125.140.255.254125.140.255.2554,094
209125.141.0.0/20125.141.0.1 to 125.141.15.254125.141.15.2554,094
210125.141.16.0/20125.141.16.1 to 125.141.31.254125.141.31.2554,094
211125.141.32.0/20125.141.32.1 to 125.141.47.254125.141.47.2554,094
212125.141.48.0/20125.141.48.1 to 125.141.63.254125.141.63.2554,094
213125.141.64.0/20125.141.64.1 to 125.141.79.254125.141.79.2554,094
214125.141.80.0/20125.141.80.1 to 125.141.95.254125.141.95.2554,094
215125.141.96.0/20125.141.96.1 to 125.141.111.254125.141.111.2554,094
216125.141.112.0/20125.141.112.1 to 125.141.127.254125.141.127.2554,094
217125.141.128.0/20125.141.128.1 to 125.141.143.254125.141.143.2554,094
218125.141.144.0/20125.141.144.1 to 125.141.159.254125.141.159.2554,094
219125.141.160.0/20125.141.160.1 to 125.141.175.254125.141.175.2554,094
220125.141.176.0/20125.141.176.1 to 125.141.191.254125.141.191.2554,094
221125.141.192.0/20125.141.192.1 to 125.141.207.254125.141.207.2554,094
222125.141.208.0/20125.141.208.1 to 125.141.223.254125.141.223.2554,094
223125.141.224.0/20125.141.224.1 to 125.141.239.254125.141.239.2554,094
224125.141.240.0/20125.141.240.1 to 125.141.255.254125.141.255.2554,094
225125.142.0.0/20125.142.0.1 to 125.142.15.254125.142.15.2554,094
226125.142.16.0/20125.142.16.1 to 125.142.31.254125.142.31.2554,094
227125.142.32.0/20125.142.32.1 to 125.142.47.254125.142.47.2554,094
228125.142.48.0/20125.142.48.1 to 125.142.63.254125.142.63.2554,094
229125.142.64.0/20125.142.64.1 to 125.142.79.254125.142.79.2554,094
230125.142.80.0/20125.142.80.1 to 125.142.95.254125.142.95.2554,094
231125.142.96.0/20125.142.96.1 to 125.142.111.254125.142.111.2554,094
232125.142.112.0/20125.142.112.1 to 125.142.127.254125.142.127.2554,094
233125.142.128.0/20125.142.128.1 to 125.142.143.254125.142.143.2554,094
234125.142.144.0/20125.142.144.1 to 125.142.159.254125.142.159.2554,094
235125.142.160.0/20125.142.160.1 to 125.142.175.254125.142.175.2554,094
236125.142.176.0/20125.142.176.1 to 125.142.191.254125.142.191.2554,094
237125.142.192.0/20125.142.192.1 to 125.142.207.254125.142.207.2554,094
238125.142.208.0/20125.142.208.1 to 125.142.223.254125.142.223.2554,094
239125.142.224.0/20125.142.224.1 to 125.142.239.254125.142.239.2554,094
240125.142.240.0/20125.142.240.1 to 125.142.255.254125.142.255.2554,094
241125.143.0.0/20125.143.0.1 to 125.143.15.254125.143.15.2554,094
242125.143.16.0/20125.143.16.1 to 125.143.31.254125.143.31.2554,094
243125.143.32.0/20125.143.32.1 to 125.143.47.254125.143.47.2554,094
244125.143.48.0/20125.143.48.1 to 125.143.63.254125.143.63.2554,094
245125.143.64.0/20125.143.64.1 to 125.143.79.254125.143.79.2554,094
246125.143.80.0/20125.143.80.1 to 125.143.95.254125.143.95.2554,094
247125.143.96.0/20125.143.96.1 to 125.143.111.254125.143.111.2554,094
248125.143.112.0/20125.143.112.1 to 125.143.127.254125.143.127.2554,094
249125.143.128.0/20125.143.128.1 to 125.143.143.254125.143.143.2554,094
250125.143.144.0/20125.143.144.1 to 125.143.159.254125.143.159.2554,094
251125.143.160.0/20125.143.160.1 to 125.143.175.254125.143.175.2554,094
252125.143.176.0/20125.143.176.1 to 125.143.191.254125.143.191.2554,094
253125.143.192.0/20125.143.192.1 to 125.143.207.254125.143.207.2554,094
254125.143.208.0/20125.143.208.1 to 125.143.223.254125.143.223.2554,094
255125.143.224.0/20125.143.224.1 to 125.143.239.254125.143.239.2554,094
256125.143.240.0/20125.143.240.1 to 125.143.255.254125.143.255.2554,094

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.