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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/19
/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 1,024 subnets of /19; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1125.128.0.0/19125.128.0.1 to 125.128.31.254125.128.31.2558,190
2125.128.32.0/19125.128.32.1 to 125.128.63.254125.128.63.2558,190
3125.128.64.0/19125.128.64.1 to 125.128.95.254125.128.95.2558,190
4125.128.96.0/19125.128.96.1 to 125.128.127.254125.128.127.2558,190
5125.128.128.0/19125.128.128.1 to 125.128.159.254125.128.159.2558,190
6125.128.160.0/19125.128.160.1 to 125.128.191.254125.128.191.2558,190
7125.128.192.0/19125.128.192.1 to 125.128.223.254125.128.223.2558,190
8125.128.224.0/19125.128.224.1 to 125.128.255.254125.128.255.2558,190
9125.129.0.0/19125.129.0.1 to 125.129.31.254125.129.31.2558,190
10125.129.32.0/19125.129.32.1 to 125.129.63.254125.129.63.2558,190
11125.129.64.0/19125.129.64.1 to 125.129.95.254125.129.95.2558,190
12125.129.96.0/19125.129.96.1 to 125.129.127.254125.129.127.2558,190
13125.129.128.0/19125.129.128.1 to 125.129.159.254125.129.159.2558,190
14125.129.160.0/19125.129.160.1 to 125.129.191.254125.129.191.2558,190
15125.129.192.0/19125.129.192.1 to 125.129.223.254125.129.223.2558,190
16125.129.224.0/19125.129.224.1 to 125.129.255.254125.129.255.2558,190
17125.130.0.0/19125.130.0.1 to 125.130.31.254125.130.31.2558,190
18125.130.32.0/19125.130.32.1 to 125.130.63.254125.130.63.2558,190
19125.130.64.0/19125.130.64.1 to 125.130.95.254125.130.95.2558,190
20125.130.96.0/19125.130.96.1 to 125.130.127.254125.130.127.2558,190
21125.130.128.0/19125.130.128.1 to 125.130.159.254125.130.159.2558,190
22125.130.160.0/19125.130.160.1 to 125.130.191.254125.130.191.2558,190
23125.130.192.0/19125.130.192.1 to 125.130.223.254125.130.223.2558,190
24125.130.224.0/19125.130.224.1 to 125.130.255.254125.130.255.2558,190
25125.131.0.0/19125.131.0.1 to 125.131.31.254125.131.31.2558,190
26125.131.32.0/19125.131.32.1 to 125.131.63.254125.131.63.2558,190
27125.131.64.0/19125.131.64.1 to 125.131.95.254125.131.95.2558,190
28125.131.96.0/19125.131.96.1 to 125.131.127.254125.131.127.2558,190
29125.131.128.0/19125.131.128.1 to 125.131.159.254125.131.159.2558,190
30125.131.160.0/19125.131.160.1 to 125.131.191.254125.131.191.2558,190
31125.131.192.0/19125.131.192.1 to 125.131.223.254125.131.223.2558,190
32125.131.224.0/19125.131.224.1 to 125.131.255.254125.131.255.2558,190
33125.132.0.0/19125.132.0.1 to 125.132.31.254125.132.31.2558,190
34125.132.32.0/19125.132.32.1 to 125.132.63.254125.132.63.2558,190
35125.132.64.0/19125.132.64.1 to 125.132.95.254125.132.95.2558,190
36125.132.96.0/19125.132.96.1 to 125.132.127.254125.132.127.2558,190
37125.132.128.0/19125.132.128.1 to 125.132.159.254125.132.159.2558,190
38125.132.160.0/19125.132.160.1 to 125.132.191.254125.132.191.2558,190
39125.132.192.0/19125.132.192.1 to 125.132.223.254125.132.223.2558,190
40125.132.224.0/19125.132.224.1 to 125.132.255.254125.132.255.2558,190
41125.133.0.0/19125.133.0.1 to 125.133.31.254125.133.31.2558,190
42125.133.32.0/19125.133.32.1 to 125.133.63.254125.133.63.2558,190
43125.133.64.0/19125.133.64.1 to 125.133.95.254125.133.95.2558,190
44125.133.96.0/19125.133.96.1 to 125.133.127.254125.133.127.2558,190
45125.133.128.0/19125.133.128.1 to 125.133.159.254125.133.159.2558,190
46125.133.160.0/19125.133.160.1 to 125.133.191.254125.133.191.2558,190
47125.133.192.0/19125.133.192.1 to 125.133.223.254125.133.223.2558,190
48125.133.224.0/19125.133.224.1 to 125.133.255.254125.133.255.2558,190
49125.134.0.0/19125.134.0.1 to 125.134.31.254125.134.31.2558,190
50125.134.32.0/19125.134.32.1 to 125.134.63.254125.134.63.2558,190
51125.134.64.0/19125.134.64.1 to 125.134.95.254125.134.95.2558,190
52125.134.96.0/19125.134.96.1 to 125.134.127.254125.134.127.2558,190
53125.134.128.0/19125.134.128.1 to 125.134.159.254125.134.159.2558,190
54125.134.160.0/19125.134.160.1 to 125.134.191.254125.134.191.2558,190
55125.134.192.0/19125.134.192.1 to 125.134.223.254125.134.223.2558,190
56125.134.224.0/19125.134.224.1 to 125.134.255.254125.134.255.2558,190
57125.135.0.0/19125.135.0.1 to 125.135.31.254125.135.31.2558,190
58125.135.32.0/19125.135.32.1 to 125.135.63.254125.135.63.2558,190
59125.135.64.0/19125.135.64.1 to 125.135.95.254125.135.95.2558,190
60125.135.96.0/19125.135.96.1 to 125.135.127.254125.135.127.2558,190
61125.135.128.0/19125.135.128.1 to 125.135.159.254125.135.159.2558,190
62125.135.160.0/19125.135.160.1 to 125.135.191.254125.135.191.2558,190
63125.135.192.0/19125.135.192.1 to 125.135.223.254125.135.223.2558,190
64125.135.224.0/19125.135.224.1 to 125.135.255.254125.135.255.2558,190
65125.136.0.0/19125.136.0.1 to 125.136.31.254125.136.31.2558,190
66125.136.32.0/19125.136.32.1 to 125.136.63.254125.136.63.2558,190
67125.136.64.0/19125.136.64.1 to 125.136.95.254125.136.95.2558,190
68125.136.96.0/19125.136.96.1 to 125.136.127.254125.136.127.2558,190
69125.136.128.0/19125.136.128.1 to 125.136.159.254125.136.159.2558,190
70125.136.160.0/19125.136.160.1 to 125.136.191.254125.136.191.2558,190
71125.136.192.0/19125.136.192.1 to 125.136.223.254125.136.223.2558,190
72125.136.224.0/19125.136.224.1 to 125.136.255.254125.136.255.2558,190
73125.137.0.0/19125.137.0.1 to 125.137.31.254125.137.31.2558,190
74125.137.32.0/19125.137.32.1 to 125.137.63.254125.137.63.2558,190
75125.137.64.0/19125.137.64.1 to 125.137.95.254125.137.95.2558,190
76125.137.96.0/19125.137.96.1 to 125.137.127.254125.137.127.2558,190
77125.137.128.0/19125.137.128.1 to 125.137.159.254125.137.159.2558,190
78125.137.160.0/19125.137.160.1 to 125.137.191.254125.137.191.2558,190
79125.137.192.0/19125.137.192.1 to 125.137.223.254125.137.223.2558,190
80125.137.224.0/19125.137.224.1 to 125.137.255.254125.137.255.2558,190
81125.138.0.0/19125.138.0.1 to 125.138.31.254125.138.31.2558,190
82125.138.32.0/19125.138.32.1 to 125.138.63.254125.138.63.2558,190
83125.138.64.0/19125.138.64.1 to 125.138.95.254125.138.95.2558,190
84125.138.96.0/19125.138.96.1 to 125.138.127.254125.138.127.2558,190
85125.138.128.0/19125.138.128.1 to 125.138.159.254125.138.159.2558,190
86125.138.160.0/19125.138.160.1 to 125.138.191.254125.138.191.2558,190
87125.138.192.0/19125.138.192.1 to 125.138.223.254125.138.223.2558,190
88125.138.224.0/19125.138.224.1 to 125.138.255.254125.138.255.2558,190
89125.139.0.0/19125.139.0.1 to 125.139.31.254125.139.31.2558,190
90125.139.32.0/19125.139.32.1 to 125.139.63.254125.139.63.2558,190
91125.139.64.0/19125.139.64.1 to 125.139.95.254125.139.95.2558,190
92125.139.96.0/19125.139.96.1 to 125.139.127.254125.139.127.2558,190
93125.139.128.0/19125.139.128.1 to 125.139.159.254125.139.159.2558,190
94125.139.160.0/19125.139.160.1 to 125.139.191.254125.139.191.2558,190
95125.139.192.0/19125.139.192.1 to 125.139.223.254125.139.223.2558,190
96125.139.224.0/19125.139.224.1 to 125.139.255.254125.139.255.2558,190
97125.140.0.0/19125.140.0.1 to 125.140.31.254125.140.31.2558,190
98125.140.32.0/19125.140.32.1 to 125.140.63.254125.140.63.2558,190
99125.140.64.0/19125.140.64.1 to 125.140.95.254125.140.95.2558,190
100125.140.96.0/19125.140.96.1 to 125.140.127.254125.140.127.2558,190
101125.140.128.0/19125.140.128.1 to 125.140.159.254125.140.159.2558,190
102125.140.160.0/19125.140.160.1 to 125.140.191.254125.140.191.2558,190
103125.140.192.0/19125.140.192.1 to 125.140.223.254125.140.223.2558,190
104125.140.224.0/19125.140.224.1 to 125.140.255.254125.140.255.2558,190
105125.141.0.0/19125.141.0.1 to 125.141.31.254125.141.31.2558,190
106125.141.32.0/19125.141.32.1 to 125.141.63.254125.141.63.2558,190
107125.141.64.0/19125.141.64.1 to 125.141.95.254125.141.95.2558,190
108125.141.96.0/19125.141.96.1 to 125.141.127.254125.141.127.2558,190
109125.141.128.0/19125.141.128.1 to 125.141.159.254125.141.159.2558,190
110125.141.160.0/19125.141.160.1 to 125.141.191.254125.141.191.2558,190
111125.141.192.0/19125.141.192.1 to 125.141.223.254125.141.223.2558,190
112125.141.224.0/19125.141.224.1 to 125.141.255.254125.141.255.2558,190
113125.142.0.0/19125.142.0.1 to 125.142.31.254125.142.31.2558,190
114125.142.32.0/19125.142.32.1 to 125.142.63.254125.142.63.2558,190
115125.142.64.0/19125.142.64.1 to 125.142.95.254125.142.95.2558,190
116125.142.96.0/19125.142.96.1 to 125.142.127.254125.142.127.2558,190
117125.142.128.0/19125.142.128.1 to 125.142.159.254125.142.159.2558,190
118125.142.160.0/19125.142.160.1 to 125.142.191.254125.142.191.2558,190
119125.142.192.0/19125.142.192.1 to 125.142.223.254125.142.223.2558,190
120125.142.224.0/19125.142.224.1 to 125.142.255.254125.142.255.2558,190
121125.143.0.0/19125.143.0.1 to 125.143.31.254125.143.31.2558,190
122125.143.32.0/19125.143.32.1 to 125.143.63.254125.143.63.2558,190
123125.143.64.0/19125.143.64.1 to 125.143.95.254125.143.95.2558,190
124125.143.96.0/19125.143.96.1 to 125.143.127.254125.143.127.2558,190
125125.143.128.0/19125.143.128.1 to 125.143.159.254125.143.159.2558,190
126125.143.160.0/19125.143.160.1 to 125.143.191.254125.143.191.2558,190
127125.143.192.0/19125.143.192.1 to 125.143.223.254125.143.223.2558,190
128125.143.224.0/19125.143.224.1 to 125.143.255.254125.143.255.2558,190
129125.144.0.0/19125.144.0.1 to 125.144.31.254125.144.31.2558,190
130125.144.32.0/19125.144.32.1 to 125.144.63.254125.144.63.2558,190
131125.144.64.0/19125.144.64.1 to 125.144.95.254125.144.95.2558,190
132125.144.96.0/19125.144.96.1 to 125.144.127.254125.144.127.2558,190
133125.144.128.0/19125.144.128.1 to 125.144.159.254125.144.159.2558,190
134125.144.160.0/19125.144.160.1 to 125.144.191.254125.144.191.2558,190
135125.144.192.0/19125.144.192.1 to 125.144.223.254125.144.223.2558,190
136125.144.224.0/19125.144.224.1 to 125.144.255.254125.144.255.2558,190
137125.145.0.0/19125.145.0.1 to 125.145.31.254125.145.31.2558,190
138125.145.32.0/19125.145.32.1 to 125.145.63.254125.145.63.2558,190
139125.145.64.0/19125.145.64.1 to 125.145.95.254125.145.95.2558,190
140125.145.96.0/19125.145.96.1 to 125.145.127.254125.145.127.2558,190
141125.145.128.0/19125.145.128.1 to 125.145.159.254125.145.159.2558,190
142125.145.160.0/19125.145.160.1 to 125.145.191.254125.145.191.2558,190
143125.145.192.0/19125.145.192.1 to 125.145.223.254125.145.223.2558,190
144125.145.224.0/19125.145.224.1 to 125.145.255.254125.145.255.2558,190
145125.146.0.0/19125.146.0.1 to 125.146.31.254125.146.31.2558,190
146125.146.32.0/19125.146.32.1 to 125.146.63.254125.146.63.2558,190
147125.146.64.0/19125.146.64.1 to 125.146.95.254125.146.95.2558,190
148125.146.96.0/19125.146.96.1 to 125.146.127.254125.146.127.2558,190
149125.146.128.0/19125.146.128.1 to 125.146.159.254125.146.159.2558,190
150125.146.160.0/19125.146.160.1 to 125.146.191.254125.146.191.2558,190
151125.146.192.0/19125.146.192.1 to 125.146.223.254125.146.223.2558,190
152125.146.224.0/19125.146.224.1 to 125.146.255.254125.146.255.2558,190
153125.147.0.0/19125.147.0.1 to 125.147.31.254125.147.31.2558,190
154125.147.32.0/19125.147.32.1 to 125.147.63.254125.147.63.2558,190
155125.147.64.0/19125.147.64.1 to 125.147.95.254125.147.95.2558,190
156125.147.96.0/19125.147.96.1 to 125.147.127.254125.147.127.2558,190
157125.147.128.0/19125.147.128.1 to 125.147.159.254125.147.159.2558,190
158125.147.160.0/19125.147.160.1 to 125.147.191.254125.147.191.2558,190
159125.147.192.0/19125.147.192.1 to 125.147.223.254125.147.223.2558,190
160125.147.224.0/19125.147.224.1 to 125.147.255.254125.147.255.2558,190
161125.148.0.0/19125.148.0.1 to 125.148.31.254125.148.31.2558,190
162125.148.32.0/19125.148.32.1 to 125.148.63.254125.148.63.2558,190
163125.148.64.0/19125.148.64.1 to 125.148.95.254125.148.95.2558,190
164125.148.96.0/19125.148.96.1 to 125.148.127.254125.148.127.2558,190
165125.148.128.0/19125.148.128.1 to 125.148.159.254125.148.159.2558,190
166125.148.160.0/19125.148.160.1 to 125.148.191.254125.148.191.2558,190
167125.148.192.0/19125.148.192.1 to 125.148.223.254125.148.223.2558,190
168125.148.224.0/19125.148.224.1 to 125.148.255.254125.148.255.2558,190
169125.149.0.0/19125.149.0.1 to 125.149.31.254125.149.31.2558,190
170125.149.32.0/19125.149.32.1 to 125.149.63.254125.149.63.2558,190
171125.149.64.0/19125.149.64.1 to 125.149.95.254125.149.95.2558,190
172125.149.96.0/19125.149.96.1 to 125.149.127.254125.149.127.2558,190
173125.149.128.0/19125.149.128.1 to 125.149.159.254125.149.159.2558,190
174125.149.160.0/19125.149.160.1 to 125.149.191.254125.149.191.2558,190
175125.149.192.0/19125.149.192.1 to 125.149.223.254125.149.223.2558,190
176125.149.224.0/19125.149.224.1 to 125.149.255.254125.149.255.2558,190
177125.150.0.0/19125.150.0.1 to 125.150.31.254125.150.31.2558,190
178125.150.32.0/19125.150.32.1 to 125.150.63.254125.150.63.2558,190
179125.150.64.0/19125.150.64.1 to 125.150.95.254125.150.95.2558,190
180125.150.96.0/19125.150.96.1 to 125.150.127.254125.150.127.2558,190
181125.150.128.0/19125.150.128.1 to 125.150.159.254125.150.159.2558,190
182125.150.160.0/19125.150.160.1 to 125.150.191.254125.150.191.2558,190
183125.150.192.0/19125.150.192.1 to 125.150.223.254125.150.223.2558,190
184125.150.224.0/19125.150.224.1 to 125.150.255.254125.150.255.2558,190
185125.151.0.0/19125.151.0.1 to 125.151.31.254125.151.31.2558,190
186125.151.32.0/19125.151.32.1 to 125.151.63.254125.151.63.2558,190
187125.151.64.0/19125.151.64.1 to 125.151.95.254125.151.95.2558,190
188125.151.96.0/19125.151.96.1 to 125.151.127.254125.151.127.2558,190
189125.151.128.0/19125.151.128.1 to 125.151.159.254125.151.159.2558,190
190125.151.160.0/19125.151.160.1 to 125.151.191.254125.151.191.2558,190
191125.151.192.0/19125.151.192.1 to 125.151.223.254125.151.223.2558,190
192125.151.224.0/19125.151.224.1 to 125.151.255.254125.151.255.2558,190
193125.152.0.0/19125.152.0.1 to 125.152.31.254125.152.31.2558,190
194125.152.32.0/19125.152.32.1 to 125.152.63.254125.152.63.2558,190
195125.152.64.0/19125.152.64.1 to 125.152.95.254125.152.95.2558,190
196125.152.96.0/19125.152.96.1 to 125.152.127.254125.152.127.2558,190
197125.152.128.0/19125.152.128.1 to 125.152.159.254125.152.159.2558,190
198125.152.160.0/19125.152.160.1 to 125.152.191.254125.152.191.2558,190
199125.152.192.0/19125.152.192.1 to 125.152.223.254125.152.223.2558,190
200125.152.224.0/19125.152.224.1 to 125.152.255.254125.152.255.2558,190
201125.153.0.0/19125.153.0.1 to 125.153.31.254125.153.31.2558,190
202125.153.32.0/19125.153.32.1 to 125.153.63.254125.153.63.2558,190
203125.153.64.0/19125.153.64.1 to 125.153.95.254125.153.95.2558,190
204125.153.96.0/19125.153.96.1 to 125.153.127.254125.153.127.2558,190
205125.153.128.0/19125.153.128.1 to 125.153.159.254125.153.159.2558,190
206125.153.160.0/19125.153.160.1 to 125.153.191.254125.153.191.2558,190
207125.153.192.0/19125.153.192.1 to 125.153.223.254125.153.223.2558,190
208125.153.224.0/19125.153.224.1 to 125.153.255.254125.153.255.2558,190
209125.154.0.0/19125.154.0.1 to 125.154.31.254125.154.31.2558,190
210125.154.32.0/19125.154.32.1 to 125.154.63.254125.154.63.2558,190
211125.154.64.0/19125.154.64.1 to 125.154.95.254125.154.95.2558,190
212125.154.96.0/19125.154.96.1 to 125.154.127.254125.154.127.2558,190
213125.154.128.0/19125.154.128.1 to 125.154.159.254125.154.159.2558,190
214125.154.160.0/19125.154.160.1 to 125.154.191.254125.154.191.2558,190
215125.154.192.0/19125.154.192.1 to 125.154.223.254125.154.223.2558,190
216125.154.224.0/19125.154.224.1 to 125.154.255.254125.154.255.2558,190
217125.155.0.0/19125.155.0.1 to 125.155.31.254125.155.31.2558,190
218125.155.32.0/19125.155.32.1 to 125.155.63.254125.155.63.2558,190
219125.155.64.0/19125.155.64.1 to 125.155.95.254125.155.95.2558,190
220125.155.96.0/19125.155.96.1 to 125.155.127.254125.155.127.2558,190
221125.155.128.0/19125.155.128.1 to 125.155.159.254125.155.159.2558,190
222125.155.160.0/19125.155.160.1 to 125.155.191.254125.155.191.2558,190
223125.155.192.0/19125.155.192.1 to 125.155.223.254125.155.223.2558,190
224125.155.224.0/19125.155.224.1 to 125.155.255.254125.155.255.2558,190
225125.156.0.0/19125.156.0.1 to 125.156.31.254125.156.31.2558,190
226125.156.32.0/19125.156.32.1 to 125.156.63.254125.156.63.2558,190
227125.156.64.0/19125.156.64.1 to 125.156.95.254125.156.95.2558,190
228125.156.96.0/19125.156.96.1 to 125.156.127.254125.156.127.2558,190
229125.156.128.0/19125.156.128.1 to 125.156.159.254125.156.159.2558,190
230125.156.160.0/19125.156.160.1 to 125.156.191.254125.156.191.2558,190
231125.156.192.0/19125.156.192.1 to 125.156.223.254125.156.223.2558,190
232125.156.224.0/19125.156.224.1 to 125.156.255.254125.156.255.2558,190
233125.157.0.0/19125.157.0.1 to 125.157.31.254125.157.31.2558,190
234125.157.32.0/19125.157.32.1 to 125.157.63.254125.157.63.2558,190
235125.157.64.0/19125.157.64.1 to 125.157.95.254125.157.95.2558,190
236125.157.96.0/19125.157.96.1 to 125.157.127.254125.157.127.2558,190
237125.157.128.0/19125.157.128.1 to 125.157.159.254125.157.159.2558,190
238125.157.160.0/19125.157.160.1 to 125.157.191.254125.157.191.2558,190
239125.157.192.0/19125.157.192.1 to 125.157.223.254125.157.223.2558,190
240125.157.224.0/19125.157.224.1 to 125.157.255.254125.157.255.2558,190
241125.158.0.0/19125.158.0.1 to 125.158.31.254125.158.31.2558,190
242125.158.32.0/19125.158.32.1 to 125.158.63.254125.158.63.2558,190
243125.158.64.0/19125.158.64.1 to 125.158.95.254125.158.95.2558,190
244125.158.96.0/19125.158.96.1 to 125.158.127.254125.158.127.2558,190
245125.158.128.0/19125.158.128.1 to 125.158.159.254125.158.159.2558,190
246125.158.160.0/19125.158.160.1 to 125.158.191.254125.158.191.2558,190
247125.158.192.0/19125.158.192.1 to 125.158.223.254125.158.223.2558,190
248125.158.224.0/19125.158.224.1 to 125.158.255.254125.158.255.2558,190
249125.159.0.0/19125.159.0.1 to 125.159.31.254125.159.31.2558,190
250125.159.32.0/19125.159.32.1 to 125.159.63.254125.159.63.2558,190
251125.159.64.0/19125.159.64.1 to 125.159.95.254125.159.95.2558,190
252125.159.96.0/19125.159.96.1 to 125.159.127.254125.159.127.2558,190
253125.159.128.0/19125.159.128.1 to 125.159.159.254125.159.159.2558,190
254125.159.160.0/19125.159.160.1 to 125.159.191.254125.159.191.2558,190
255125.159.192.0/19125.159.192.1 to 125.159.223.254125.159.223.2558,190
256125.159.224.0/19125.159.224.1 to 125.159.255.254125.159.255.2558,190

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.