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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/21
/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 4,096 subnets of /21; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1125.128.0.0/21125.128.0.1 to 125.128.7.254125.128.7.2552,046
2125.128.8.0/21125.128.8.1 to 125.128.15.254125.128.15.2552,046
3125.128.16.0/21125.128.16.1 to 125.128.23.254125.128.23.2552,046
4125.128.24.0/21125.128.24.1 to 125.128.31.254125.128.31.2552,046
5125.128.32.0/21125.128.32.1 to 125.128.39.254125.128.39.2552,046
6125.128.40.0/21125.128.40.1 to 125.128.47.254125.128.47.2552,046
7125.128.48.0/21125.128.48.1 to 125.128.55.254125.128.55.2552,046
8125.128.56.0/21125.128.56.1 to 125.128.63.254125.128.63.2552,046
9125.128.64.0/21125.128.64.1 to 125.128.71.254125.128.71.2552,046
10125.128.72.0/21125.128.72.1 to 125.128.79.254125.128.79.2552,046
11125.128.80.0/21125.128.80.1 to 125.128.87.254125.128.87.2552,046
12125.128.88.0/21125.128.88.1 to 125.128.95.254125.128.95.2552,046
13125.128.96.0/21125.128.96.1 to 125.128.103.254125.128.103.2552,046
14125.128.104.0/21125.128.104.1 to 125.128.111.254125.128.111.2552,046
15125.128.112.0/21125.128.112.1 to 125.128.119.254125.128.119.2552,046
16125.128.120.0/21125.128.120.1 to 125.128.127.254125.128.127.2552,046
17125.128.128.0/21125.128.128.1 to 125.128.135.254125.128.135.2552,046
18125.128.136.0/21125.128.136.1 to 125.128.143.254125.128.143.2552,046
19125.128.144.0/21125.128.144.1 to 125.128.151.254125.128.151.2552,046
20125.128.152.0/21125.128.152.1 to 125.128.159.254125.128.159.2552,046
21125.128.160.0/21125.128.160.1 to 125.128.167.254125.128.167.2552,046
22125.128.168.0/21125.128.168.1 to 125.128.175.254125.128.175.2552,046
23125.128.176.0/21125.128.176.1 to 125.128.183.254125.128.183.2552,046
24125.128.184.0/21125.128.184.1 to 125.128.191.254125.128.191.2552,046
25125.128.192.0/21125.128.192.1 to 125.128.199.254125.128.199.2552,046
26125.128.200.0/21125.128.200.1 to 125.128.207.254125.128.207.2552,046
27125.128.208.0/21125.128.208.1 to 125.128.215.254125.128.215.2552,046
28125.128.216.0/21125.128.216.1 to 125.128.223.254125.128.223.2552,046
29125.128.224.0/21125.128.224.1 to 125.128.231.254125.128.231.2552,046
30125.128.232.0/21125.128.232.1 to 125.128.239.254125.128.239.2552,046
31125.128.240.0/21125.128.240.1 to 125.128.247.254125.128.247.2552,046
32125.128.248.0/21125.128.248.1 to 125.128.255.254125.128.255.2552,046
33125.129.0.0/21125.129.0.1 to 125.129.7.254125.129.7.2552,046
34125.129.8.0/21125.129.8.1 to 125.129.15.254125.129.15.2552,046
35125.129.16.0/21125.129.16.1 to 125.129.23.254125.129.23.2552,046
36125.129.24.0/21125.129.24.1 to 125.129.31.254125.129.31.2552,046
37125.129.32.0/21125.129.32.1 to 125.129.39.254125.129.39.2552,046
38125.129.40.0/21125.129.40.1 to 125.129.47.254125.129.47.2552,046
39125.129.48.0/21125.129.48.1 to 125.129.55.254125.129.55.2552,046
40125.129.56.0/21125.129.56.1 to 125.129.63.254125.129.63.2552,046
41125.129.64.0/21125.129.64.1 to 125.129.71.254125.129.71.2552,046
42125.129.72.0/21125.129.72.1 to 125.129.79.254125.129.79.2552,046
43125.129.80.0/21125.129.80.1 to 125.129.87.254125.129.87.2552,046
44125.129.88.0/21125.129.88.1 to 125.129.95.254125.129.95.2552,046
45125.129.96.0/21125.129.96.1 to 125.129.103.254125.129.103.2552,046
46125.129.104.0/21125.129.104.1 to 125.129.111.254125.129.111.2552,046
47125.129.112.0/21125.129.112.1 to 125.129.119.254125.129.119.2552,046
48125.129.120.0/21125.129.120.1 to 125.129.127.254125.129.127.2552,046
49125.129.128.0/21125.129.128.1 to 125.129.135.254125.129.135.2552,046
50125.129.136.0/21125.129.136.1 to 125.129.143.254125.129.143.2552,046
51125.129.144.0/21125.129.144.1 to 125.129.151.254125.129.151.2552,046
52125.129.152.0/21125.129.152.1 to 125.129.159.254125.129.159.2552,046
53125.129.160.0/21125.129.160.1 to 125.129.167.254125.129.167.2552,046
54125.129.168.0/21125.129.168.1 to 125.129.175.254125.129.175.2552,046
55125.129.176.0/21125.129.176.1 to 125.129.183.254125.129.183.2552,046
56125.129.184.0/21125.129.184.1 to 125.129.191.254125.129.191.2552,046
57125.129.192.0/21125.129.192.1 to 125.129.199.254125.129.199.2552,046
58125.129.200.0/21125.129.200.1 to 125.129.207.254125.129.207.2552,046
59125.129.208.0/21125.129.208.1 to 125.129.215.254125.129.215.2552,046
60125.129.216.0/21125.129.216.1 to 125.129.223.254125.129.223.2552,046
61125.129.224.0/21125.129.224.1 to 125.129.231.254125.129.231.2552,046
62125.129.232.0/21125.129.232.1 to 125.129.239.254125.129.239.2552,046
63125.129.240.0/21125.129.240.1 to 125.129.247.254125.129.247.2552,046
64125.129.248.0/21125.129.248.1 to 125.129.255.254125.129.255.2552,046
65125.130.0.0/21125.130.0.1 to 125.130.7.254125.130.7.2552,046
66125.130.8.0/21125.130.8.1 to 125.130.15.254125.130.15.2552,046
67125.130.16.0/21125.130.16.1 to 125.130.23.254125.130.23.2552,046
68125.130.24.0/21125.130.24.1 to 125.130.31.254125.130.31.2552,046
69125.130.32.0/21125.130.32.1 to 125.130.39.254125.130.39.2552,046
70125.130.40.0/21125.130.40.1 to 125.130.47.254125.130.47.2552,046
71125.130.48.0/21125.130.48.1 to 125.130.55.254125.130.55.2552,046
72125.130.56.0/21125.130.56.1 to 125.130.63.254125.130.63.2552,046
73125.130.64.0/21125.130.64.1 to 125.130.71.254125.130.71.2552,046
74125.130.72.0/21125.130.72.1 to 125.130.79.254125.130.79.2552,046
75125.130.80.0/21125.130.80.1 to 125.130.87.254125.130.87.2552,046
76125.130.88.0/21125.130.88.1 to 125.130.95.254125.130.95.2552,046
77125.130.96.0/21125.130.96.1 to 125.130.103.254125.130.103.2552,046
78125.130.104.0/21125.130.104.1 to 125.130.111.254125.130.111.2552,046
79125.130.112.0/21125.130.112.1 to 125.130.119.254125.130.119.2552,046
80125.130.120.0/21125.130.120.1 to 125.130.127.254125.130.127.2552,046
81125.130.128.0/21125.130.128.1 to 125.130.135.254125.130.135.2552,046
82125.130.136.0/21125.130.136.1 to 125.130.143.254125.130.143.2552,046
83125.130.144.0/21125.130.144.1 to 125.130.151.254125.130.151.2552,046
84125.130.152.0/21125.130.152.1 to 125.130.159.254125.130.159.2552,046
85125.130.160.0/21125.130.160.1 to 125.130.167.254125.130.167.2552,046
86125.130.168.0/21125.130.168.1 to 125.130.175.254125.130.175.2552,046
87125.130.176.0/21125.130.176.1 to 125.130.183.254125.130.183.2552,046
88125.130.184.0/21125.130.184.1 to 125.130.191.254125.130.191.2552,046
89125.130.192.0/21125.130.192.1 to 125.130.199.254125.130.199.2552,046
90125.130.200.0/21125.130.200.1 to 125.130.207.254125.130.207.2552,046
91125.130.208.0/21125.130.208.1 to 125.130.215.254125.130.215.2552,046
92125.130.216.0/21125.130.216.1 to 125.130.223.254125.130.223.2552,046
93125.130.224.0/21125.130.224.1 to 125.130.231.254125.130.231.2552,046
94125.130.232.0/21125.130.232.1 to 125.130.239.254125.130.239.2552,046
95125.130.240.0/21125.130.240.1 to 125.130.247.254125.130.247.2552,046
96125.130.248.0/21125.130.248.1 to 125.130.255.254125.130.255.2552,046
97125.131.0.0/21125.131.0.1 to 125.131.7.254125.131.7.2552,046
98125.131.8.0/21125.131.8.1 to 125.131.15.254125.131.15.2552,046
99125.131.16.0/21125.131.16.1 to 125.131.23.254125.131.23.2552,046
100125.131.24.0/21125.131.24.1 to 125.131.31.254125.131.31.2552,046
101125.131.32.0/21125.131.32.1 to 125.131.39.254125.131.39.2552,046
102125.131.40.0/21125.131.40.1 to 125.131.47.254125.131.47.2552,046
103125.131.48.0/21125.131.48.1 to 125.131.55.254125.131.55.2552,046
104125.131.56.0/21125.131.56.1 to 125.131.63.254125.131.63.2552,046
105125.131.64.0/21125.131.64.1 to 125.131.71.254125.131.71.2552,046
106125.131.72.0/21125.131.72.1 to 125.131.79.254125.131.79.2552,046
107125.131.80.0/21125.131.80.1 to 125.131.87.254125.131.87.2552,046
108125.131.88.0/21125.131.88.1 to 125.131.95.254125.131.95.2552,046
109125.131.96.0/21125.131.96.1 to 125.131.103.254125.131.103.2552,046
110125.131.104.0/21125.131.104.1 to 125.131.111.254125.131.111.2552,046
111125.131.112.0/21125.131.112.1 to 125.131.119.254125.131.119.2552,046
112125.131.120.0/21125.131.120.1 to 125.131.127.254125.131.127.2552,046
113125.131.128.0/21125.131.128.1 to 125.131.135.254125.131.135.2552,046
114125.131.136.0/21125.131.136.1 to 125.131.143.254125.131.143.2552,046
115125.131.144.0/21125.131.144.1 to 125.131.151.254125.131.151.2552,046
116125.131.152.0/21125.131.152.1 to 125.131.159.254125.131.159.2552,046
117125.131.160.0/21125.131.160.1 to 125.131.167.254125.131.167.2552,046
118125.131.168.0/21125.131.168.1 to 125.131.175.254125.131.175.2552,046
119125.131.176.0/21125.131.176.1 to 125.131.183.254125.131.183.2552,046
120125.131.184.0/21125.131.184.1 to 125.131.191.254125.131.191.2552,046
121125.131.192.0/21125.131.192.1 to 125.131.199.254125.131.199.2552,046
122125.131.200.0/21125.131.200.1 to 125.131.207.254125.131.207.2552,046
123125.131.208.0/21125.131.208.1 to 125.131.215.254125.131.215.2552,046
124125.131.216.0/21125.131.216.1 to 125.131.223.254125.131.223.2552,046
125125.131.224.0/21125.131.224.1 to 125.131.231.254125.131.231.2552,046
126125.131.232.0/21125.131.232.1 to 125.131.239.254125.131.239.2552,046
127125.131.240.0/21125.131.240.1 to 125.131.247.254125.131.247.2552,046
128125.131.248.0/21125.131.248.1 to 125.131.255.254125.131.255.2552,046
129125.132.0.0/21125.132.0.1 to 125.132.7.254125.132.7.2552,046
130125.132.8.0/21125.132.8.1 to 125.132.15.254125.132.15.2552,046
131125.132.16.0/21125.132.16.1 to 125.132.23.254125.132.23.2552,046
132125.132.24.0/21125.132.24.1 to 125.132.31.254125.132.31.2552,046
133125.132.32.0/21125.132.32.1 to 125.132.39.254125.132.39.2552,046
134125.132.40.0/21125.132.40.1 to 125.132.47.254125.132.47.2552,046
135125.132.48.0/21125.132.48.1 to 125.132.55.254125.132.55.2552,046
136125.132.56.0/21125.132.56.1 to 125.132.63.254125.132.63.2552,046
137125.132.64.0/21125.132.64.1 to 125.132.71.254125.132.71.2552,046
138125.132.72.0/21125.132.72.1 to 125.132.79.254125.132.79.2552,046
139125.132.80.0/21125.132.80.1 to 125.132.87.254125.132.87.2552,046
140125.132.88.0/21125.132.88.1 to 125.132.95.254125.132.95.2552,046
141125.132.96.0/21125.132.96.1 to 125.132.103.254125.132.103.2552,046
142125.132.104.0/21125.132.104.1 to 125.132.111.254125.132.111.2552,046
143125.132.112.0/21125.132.112.1 to 125.132.119.254125.132.119.2552,046
144125.132.120.0/21125.132.120.1 to 125.132.127.254125.132.127.2552,046
145125.132.128.0/21125.132.128.1 to 125.132.135.254125.132.135.2552,046
146125.132.136.0/21125.132.136.1 to 125.132.143.254125.132.143.2552,046
147125.132.144.0/21125.132.144.1 to 125.132.151.254125.132.151.2552,046
148125.132.152.0/21125.132.152.1 to 125.132.159.254125.132.159.2552,046
149125.132.160.0/21125.132.160.1 to 125.132.167.254125.132.167.2552,046
150125.132.168.0/21125.132.168.1 to 125.132.175.254125.132.175.2552,046
151125.132.176.0/21125.132.176.1 to 125.132.183.254125.132.183.2552,046
152125.132.184.0/21125.132.184.1 to 125.132.191.254125.132.191.2552,046
153125.132.192.0/21125.132.192.1 to 125.132.199.254125.132.199.2552,046
154125.132.200.0/21125.132.200.1 to 125.132.207.254125.132.207.2552,046
155125.132.208.0/21125.132.208.1 to 125.132.215.254125.132.215.2552,046
156125.132.216.0/21125.132.216.1 to 125.132.223.254125.132.223.2552,046
157125.132.224.0/21125.132.224.1 to 125.132.231.254125.132.231.2552,046
158125.132.232.0/21125.132.232.1 to 125.132.239.254125.132.239.2552,046
159125.132.240.0/21125.132.240.1 to 125.132.247.254125.132.247.2552,046
160125.132.248.0/21125.132.248.1 to 125.132.255.254125.132.255.2552,046
161125.133.0.0/21125.133.0.1 to 125.133.7.254125.133.7.2552,046
162125.133.8.0/21125.133.8.1 to 125.133.15.254125.133.15.2552,046
163125.133.16.0/21125.133.16.1 to 125.133.23.254125.133.23.2552,046
164125.133.24.0/21125.133.24.1 to 125.133.31.254125.133.31.2552,046
165125.133.32.0/21125.133.32.1 to 125.133.39.254125.133.39.2552,046
166125.133.40.0/21125.133.40.1 to 125.133.47.254125.133.47.2552,046
167125.133.48.0/21125.133.48.1 to 125.133.55.254125.133.55.2552,046
168125.133.56.0/21125.133.56.1 to 125.133.63.254125.133.63.2552,046
169125.133.64.0/21125.133.64.1 to 125.133.71.254125.133.71.2552,046
170125.133.72.0/21125.133.72.1 to 125.133.79.254125.133.79.2552,046
171125.133.80.0/21125.133.80.1 to 125.133.87.254125.133.87.2552,046
172125.133.88.0/21125.133.88.1 to 125.133.95.254125.133.95.2552,046
173125.133.96.0/21125.133.96.1 to 125.133.103.254125.133.103.2552,046
174125.133.104.0/21125.133.104.1 to 125.133.111.254125.133.111.2552,046
175125.133.112.0/21125.133.112.1 to 125.133.119.254125.133.119.2552,046
176125.133.120.0/21125.133.120.1 to 125.133.127.254125.133.127.2552,046
177125.133.128.0/21125.133.128.1 to 125.133.135.254125.133.135.2552,046
178125.133.136.0/21125.133.136.1 to 125.133.143.254125.133.143.2552,046
179125.133.144.0/21125.133.144.1 to 125.133.151.254125.133.151.2552,046
180125.133.152.0/21125.133.152.1 to 125.133.159.254125.133.159.2552,046
181125.133.160.0/21125.133.160.1 to 125.133.167.254125.133.167.2552,046
182125.133.168.0/21125.133.168.1 to 125.133.175.254125.133.175.2552,046
183125.133.176.0/21125.133.176.1 to 125.133.183.254125.133.183.2552,046
184125.133.184.0/21125.133.184.1 to 125.133.191.254125.133.191.2552,046
185125.133.192.0/21125.133.192.1 to 125.133.199.254125.133.199.2552,046
186125.133.200.0/21125.133.200.1 to 125.133.207.254125.133.207.2552,046
187125.133.208.0/21125.133.208.1 to 125.133.215.254125.133.215.2552,046
188125.133.216.0/21125.133.216.1 to 125.133.223.254125.133.223.2552,046
189125.133.224.0/21125.133.224.1 to 125.133.231.254125.133.231.2552,046
190125.133.232.0/21125.133.232.1 to 125.133.239.254125.133.239.2552,046
191125.133.240.0/21125.133.240.1 to 125.133.247.254125.133.247.2552,046
192125.133.248.0/21125.133.248.1 to 125.133.255.254125.133.255.2552,046
193125.134.0.0/21125.134.0.1 to 125.134.7.254125.134.7.2552,046
194125.134.8.0/21125.134.8.1 to 125.134.15.254125.134.15.2552,046
195125.134.16.0/21125.134.16.1 to 125.134.23.254125.134.23.2552,046
196125.134.24.0/21125.134.24.1 to 125.134.31.254125.134.31.2552,046
197125.134.32.0/21125.134.32.1 to 125.134.39.254125.134.39.2552,046
198125.134.40.0/21125.134.40.1 to 125.134.47.254125.134.47.2552,046
199125.134.48.0/21125.134.48.1 to 125.134.55.254125.134.55.2552,046
200125.134.56.0/21125.134.56.1 to 125.134.63.254125.134.63.2552,046
201125.134.64.0/21125.134.64.1 to 125.134.71.254125.134.71.2552,046
202125.134.72.0/21125.134.72.1 to 125.134.79.254125.134.79.2552,046
203125.134.80.0/21125.134.80.1 to 125.134.87.254125.134.87.2552,046
204125.134.88.0/21125.134.88.1 to 125.134.95.254125.134.95.2552,046
205125.134.96.0/21125.134.96.1 to 125.134.103.254125.134.103.2552,046
206125.134.104.0/21125.134.104.1 to 125.134.111.254125.134.111.2552,046
207125.134.112.0/21125.134.112.1 to 125.134.119.254125.134.119.2552,046
208125.134.120.0/21125.134.120.1 to 125.134.127.254125.134.127.2552,046
209125.134.128.0/21125.134.128.1 to 125.134.135.254125.134.135.2552,046
210125.134.136.0/21125.134.136.1 to 125.134.143.254125.134.143.2552,046
211125.134.144.0/21125.134.144.1 to 125.134.151.254125.134.151.2552,046
212125.134.152.0/21125.134.152.1 to 125.134.159.254125.134.159.2552,046
213125.134.160.0/21125.134.160.1 to 125.134.167.254125.134.167.2552,046
214125.134.168.0/21125.134.168.1 to 125.134.175.254125.134.175.2552,046
215125.134.176.0/21125.134.176.1 to 125.134.183.254125.134.183.2552,046
216125.134.184.0/21125.134.184.1 to 125.134.191.254125.134.191.2552,046
217125.134.192.0/21125.134.192.1 to 125.134.199.254125.134.199.2552,046
218125.134.200.0/21125.134.200.1 to 125.134.207.254125.134.207.2552,046
219125.134.208.0/21125.134.208.1 to 125.134.215.254125.134.215.2552,046
220125.134.216.0/21125.134.216.1 to 125.134.223.254125.134.223.2552,046
221125.134.224.0/21125.134.224.1 to 125.134.231.254125.134.231.2552,046
222125.134.232.0/21125.134.232.1 to 125.134.239.254125.134.239.2552,046
223125.134.240.0/21125.134.240.1 to 125.134.247.254125.134.247.2552,046
224125.134.248.0/21125.134.248.1 to 125.134.255.254125.134.255.2552,046
225125.135.0.0/21125.135.0.1 to 125.135.7.254125.135.7.2552,046
226125.135.8.0/21125.135.8.1 to 125.135.15.254125.135.15.2552,046
227125.135.16.0/21125.135.16.1 to 125.135.23.254125.135.23.2552,046
228125.135.24.0/21125.135.24.1 to 125.135.31.254125.135.31.2552,046
229125.135.32.0/21125.135.32.1 to 125.135.39.254125.135.39.2552,046
230125.135.40.0/21125.135.40.1 to 125.135.47.254125.135.47.2552,046
231125.135.48.0/21125.135.48.1 to 125.135.55.254125.135.55.2552,046
232125.135.56.0/21125.135.56.1 to 125.135.63.254125.135.63.2552,046
233125.135.64.0/21125.135.64.1 to 125.135.71.254125.135.71.2552,046
234125.135.72.0/21125.135.72.1 to 125.135.79.254125.135.79.2552,046
235125.135.80.0/21125.135.80.1 to 125.135.87.254125.135.87.2552,046
236125.135.88.0/21125.135.88.1 to 125.135.95.254125.135.95.2552,046
237125.135.96.0/21125.135.96.1 to 125.135.103.254125.135.103.2552,046
238125.135.104.0/21125.135.104.1 to 125.135.111.254125.135.111.2552,046
239125.135.112.0/21125.135.112.1 to 125.135.119.254125.135.119.2552,046
240125.135.120.0/21125.135.120.1 to 125.135.127.254125.135.127.2552,046
241125.135.128.0/21125.135.128.1 to 125.135.135.254125.135.135.2552,046
242125.135.136.0/21125.135.136.1 to 125.135.143.254125.135.143.2552,046
243125.135.144.0/21125.135.144.1 to 125.135.151.254125.135.151.2552,046
244125.135.152.0/21125.135.152.1 to 125.135.159.254125.135.159.2552,046
245125.135.160.0/21125.135.160.1 to 125.135.167.254125.135.167.2552,046
246125.135.168.0/21125.135.168.1 to 125.135.175.254125.135.175.2552,046
247125.135.176.0/21125.135.176.1 to 125.135.183.254125.135.183.2552,046
248125.135.184.0/21125.135.184.1 to 125.135.191.254125.135.191.2552,046
249125.135.192.0/21125.135.192.1 to 125.135.199.254125.135.199.2552,046
250125.135.200.0/21125.135.200.1 to 125.135.207.254125.135.207.2552,046
251125.135.208.0/21125.135.208.1 to 125.135.215.254125.135.215.2552,046
252125.135.216.0/21125.135.216.1 to 125.135.223.254125.135.223.2552,046
253125.135.224.0/21125.135.224.1 to 125.135.231.254125.135.231.2552,046
254125.135.232.0/21125.135.232.1 to 125.135.239.254125.135.239.2552,046
255125.135.240.0/21125.135.240.1 to 125.135.247.254125.135.247.2552,046
256125.135.248.0/21125.135.248.1 to 125.135.255.254125.135.255.2552,046

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.