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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.

Network108.128.0.0/9
Usable hosts8,388,606
Subnet mask255.128.0.0
Addresses8,388,608
Network address
108.128.0.0
Broadcast address
108.255.255.255
First usable
108.128.0.1
Last usable
108.255.255.254
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 6C800000 · Integer 1820327936 to 1828716543
Reverse DNS zones
128.108.in-addr.arpa
129.108.in-addr.arpa
130.108.in-addr.arpa
131.108.in-addr.arpa
132.108.in-addr.arpa
133.108.in-addr.arpa
134.108.in-addr.arpa
135.108.in-addr.arpa
136.108.in-addr.arpa
137.108.in-addr.arpa
138.108.in-addr.arpa
139.108.in-addr.arpa
140.108.in-addr.arpa
141.108.in-addr.arpa
142.108.in-addr.arpa
143.108.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
Address01101100.10000000.00000000.00000000108.128.0.0
Subnet mask11111111.10000000.00000000.00000000255.128.0.0
Network01101100.10000000.00000000.00000000108.128.0.0
Broadcast01101100.11111111.11111111.11111111108.255.255.255
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)

108.128.0.0/9 makes 4,096 subnets of /21; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1108.128.0.0/21108.128.0.1 to 108.128.7.254108.128.7.2552,046
2108.128.8.0/21108.128.8.1 to 108.128.15.254108.128.15.2552,046
3108.128.16.0/21108.128.16.1 to 108.128.23.254108.128.23.2552,046
4108.128.24.0/21108.128.24.1 to 108.128.31.254108.128.31.2552,046
5108.128.32.0/21108.128.32.1 to 108.128.39.254108.128.39.2552,046
6108.128.40.0/21108.128.40.1 to 108.128.47.254108.128.47.2552,046
7108.128.48.0/21108.128.48.1 to 108.128.55.254108.128.55.2552,046
8108.128.56.0/21108.128.56.1 to 108.128.63.254108.128.63.2552,046
9108.128.64.0/21108.128.64.1 to 108.128.71.254108.128.71.2552,046
10108.128.72.0/21108.128.72.1 to 108.128.79.254108.128.79.2552,046
11108.128.80.0/21108.128.80.1 to 108.128.87.254108.128.87.2552,046
12108.128.88.0/21108.128.88.1 to 108.128.95.254108.128.95.2552,046
13108.128.96.0/21108.128.96.1 to 108.128.103.254108.128.103.2552,046
14108.128.104.0/21108.128.104.1 to 108.128.111.254108.128.111.2552,046
15108.128.112.0/21108.128.112.1 to 108.128.119.254108.128.119.2552,046
16108.128.120.0/21108.128.120.1 to 108.128.127.254108.128.127.2552,046
17108.128.128.0/21108.128.128.1 to 108.128.135.254108.128.135.2552,046
18108.128.136.0/21108.128.136.1 to 108.128.143.254108.128.143.2552,046
19108.128.144.0/21108.128.144.1 to 108.128.151.254108.128.151.2552,046
20108.128.152.0/21108.128.152.1 to 108.128.159.254108.128.159.2552,046
21108.128.160.0/21108.128.160.1 to 108.128.167.254108.128.167.2552,046
22108.128.168.0/21108.128.168.1 to 108.128.175.254108.128.175.2552,046
23108.128.176.0/21108.128.176.1 to 108.128.183.254108.128.183.2552,046
24108.128.184.0/21108.128.184.1 to 108.128.191.254108.128.191.2552,046
25108.128.192.0/21108.128.192.1 to 108.128.199.254108.128.199.2552,046
26108.128.200.0/21108.128.200.1 to 108.128.207.254108.128.207.2552,046
27108.128.208.0/21108.128.208.1 to 108.128.215.254108.128.215.2552,046
28108.128.216.0/21108.128.216.1 to 108.128.223.254108.128.223.2552,046
29108.128.224.0/21108.128.224.1 to 108.128.231.254108.128.231.2552,046
30108.128.232.0/21108.128.232.1 to 108.128.239.254108.128.239.2552,046
31108.128.240.0/21108.128.240.1 to 108.128.247.254108.128.247.2552,046
32108.128.248.0/21108.128.248.1 to 108.128.255.254108.128.255.2552,046
33108.129.0.0/21108.129.0.1 to 108.129.7.254108.129.7.2552,046
34108.129.8.0/21108.129.8.1 to 108.129.15.254108.129.15.2552,046
35108.129.16.0/21108.129.16.1 to 108.129.23.254108.129.23.2552,046
36108.129.24.0/21108.129.24.1 to 108.129.31.254108.129.31.2552,046
37108.129.32.0/21108.129.32.1 to 108.129.39.254108.129.39.2552,046
38108.129.40.0/21108.129.40.1 to 108.129.47.254108.129.47.2552,046
39108.129.48.0/21108.129.48.1 to 108.129.55.254108.129.55.2552,046
40108.129.56.0/21108.129.56.1 to 108.129.63.254108.129.63.2552,046
41108.129.64.0/21108.129.64.1 to 108.129.71.254108.129.71.2552,046
42108.129.72.0/21108.129.72.1 to 108.129.79.254108.129.79.2552,046
43108.129.80.0/21108.129.80.1 to 108.129.87.254108.129.87.2552,046
44108.129.88.0/21108.129.88.1 to 108.129.95.254108.129.95.2552,046
45108.129.96.0/21108.129.96.1 to 108.129.103.254108.129.103.2552,046
46108.129.104.0/21108.129.104.1 to 108.129.111.254108.129.111.2552,046
47108.129.112.0/21108.129.112.1 to 108.129.119.254108.129.119.2552,046
48108.129.120.0/21108.129.120.1 to 108.129.127.254108.129.127.2552,046
49108.129.128.0/21108.129.128.1 to 108.129.135.254108.129.135.2552,046
50108.129.136.0/21108.129.136.1 to 108.129.143.254108.129.143.2552,046
51108.129.144.0/21108.129.144.1 to 108.129.151.254108.129.151.2552,046
52108.129.152.0/21108.129.152.1 to 108.129.159.254108.129.159.2552,046
53108.129.160.0/21108.129.160.1 to 108.129.167.254108.129.167.2552,046
54108.129.168.0/21108.129.168.1 to 108.129.175.254108.129.175.2552,046
55108.129.176.0/21108.129.176.1 to 108.129.183.254108.129.183.2552,046
56108.129.184.0/21108.129.184.1 to 108.129.191.254108.129.191.2552,046
57108.129.192.0/21108.129.192.1 to 108.129.199.254108.129.199.2552,046
58108.129.200.0/21108.129.200.1 to 108.129.207.254108.129.207.2552,046
59108.129.208.0/21108.129.208.1 to 108.129.215.254108.129.215.2552,046
60108.129.216.0/21108.129.216.1 to 108.129.223.254108.129.223.2552,046
61108.129.224.0/21108.129.224.1 to 108.129.231.254108.129.231.2552,046
62108.129.232.0/21108.129.232.1 to 108.129.239.254108.129.239.2552,046
63108.129.240.0/21108.129.240.1 to 108.129.247.254108.129.247.2552,046
64108.129.248.0/21108.129.248.1 to 108.129.255.254108.129.255.2552,046
65108.130.0.0/21108.130.0.1 to 108.130.7.254108.130.7.2552,046
66108.130.8.0/21108.130.8.1 to 108.130.15.254108.130.15.2552,046
67108.130.16.0/21108.130.16.1 to 108.130.23.254108.130.23.2552,046
68108.130.24.0/21108.130.24.1 to 108.130.31.254108.130.31.2552,046
69108.130.32.0/21108.130.32.1 to 108.130.39.254108.130.39.2552,046
70108.130.40.0/21108.130.40.1 to 108.130.47.254108.130.47.2552,046
71108.130.48.0/21108.130.48.1 to 108.130.55.254108.130.55.2552,046
72108.130.56.0/21108.130.56.1 to 108.130.63.254108.130.63.2552,046
73108.130.64.0/21108.130.64.1 to 108.130.71.254108.130.71.2552,046
74108.130.72.0/21108.130.72.1 to 108.130.79.254108.130.79.2552,046
75108.130.80.0/21108.130.80.1 to 108.130.87.254108.130.87.2552,046
76108.130.88.0/21108.130.88.1 to 108.130.95.254108.130.95.2552,046
77108.130.96.0/21108.130.96.1 to 108.130.103.254108.130.103.2552,046
78108.130.104.0/21108.130.104.1 to 108.130.111.254108.130.111.2552,046
79108.130.112.0/21108.130.112.1 to 108.130.119.254108.130.119.2552,046
80108.130.120.0/21108.130.120.1 to 108.130.127.254108.130.127.2552,046
81108.130.128.0/21108.130.128.1 to 108.130.135.254108.130.135.2552,046
82108.130.136.0/21108.130.136.1 to 108.130.143.254108.130.143.2552,046
83108.130.144.0/21108.130.144.1 to 108.130.151.254108.130.151.2552,046
84108.130.152.0/21108.130.152.1 to 108.130.159.254108.130.159.2552,046
85108.130.160.0/21108.130.160.1 to 108.130.167.254108.130.167.2552,046
86108.130.168.0/21108.130.168.1 to 108.130.175.254108.130.175.2552,046
87108.130.176.0/21108.130.176.1 to 108.130.183.254108.130.183.2552,046
88108.130.184.0/21108.130.184.1 to 108.130.191.254108.130.191.2552,046
89108.130.192.0/21108.130.192.1 to 108.130.199.254108.130.199.2552,046
90108.130.200.0/21108.130.200.1 to 108.130.207.254108.130.207.2552,046
91108.130.208.0/21108.130.208.1 to 108.130.215.254108.130.215.2552,046
92108.130.216.0/21108.130.216.1 to 108.130.223.254108.130.223.2552,046
93108.130.224.0/21108.130.224.1 to 108.130.231.254108.130.231.2552,046
94108.130.232.0/21108.130.232.1 to 108.130.239.254108.130.239.2552,046
95108.130.240.0/21108.130.240.1 to 108.130.247.254108.130.247.2552,046
96108.130.248.0/21108.130.248.1 to 108.130.255.254108.130.255.2552,046
97108.131.0.0/21108.131.0.1 to 108.131.7.254108.131.7.2552,046
98108.131.8.0/21108.131.8.1 to 108.131.15.254108.131.15.2552,046
99108.131.16.0/21108.131.16.1 to 108.131.23.254108.131.23.2552,046
100108.131.24.0/21108.131.24.1 to 108.131.31.254108.131.31.2552,046
101108.131.32.0/21108.131.32.1 to 108.131.39.254108.131.39.2552,046
102108.131.40.0/21108.131.40.1 to 108.131.47.254108.131.47.2552,046
103108.131.48.0/21108.131.48.1 to 108.131.55.254108.131.55.2552,046
104108.131.56.0/21108.131.56.1 to 108.131.63.254108.131.63.2552,046
105108.131.64.0/21108.131.64.1 to 108.131.71.254108.131.71.2552,046
106108.131.72.0/21108.131.72.1 to 108.131.79.254108.131.79.2552,046
107108.131.80.0/21108.131.80.1 to 108.131.87.254108.131.87.2552,046
108108.131.88.0/21108.131.88.1 to 108.131.95.254108.131.95.2552,046
109108.131.96.0/21108.131.96.1 to 108.131.103.254108.131.103.2552,046
110108.131.104.0/21108.131.104.1 to 108.131.111.254108.131.111.2552,046
111108.131.112.0/21108.131.112.1 to 108.131.119.254108.131.119.2552,046
112108.131.120.0/21108.131.120.1 to 108.131.127.254108.131.127.2552,046
113108.131.128.0/21108.131.128.1 to 108.131.135.254108.131.135.2552,046
114108.131.136.0/21108.131.136.1 to 108.131.143.254108.131.143.2552,046
115108.131.144.0/21108.131.144.1 to 108.131.151.254108.131.151.2552,046
116108.131.152.0/21108.131.152.1 to 108.131.159.254108.131.159.2552,046
117108.131.160.0/21108.131.160.1 to 108.131.167.254108.131.167.2552,046
118108.131.168.0/21108.131.168.1 to 108.131.175.254108.131.175.2552,046
119108.131.176.0/21108.131.176.1 to 108.131.183.254108.131.183.2552,046
120108.131.184.0/21108.131.184.1 to 108.131.191.254108.131.191.2552,046
121108.131.192.0/21108.131.192.1 to 108.131.199.254108.131.199.2552,046
122108.131.200.0/21108.131.200.1 to 108.131.207.254108.131.207.2552,046
123108.131.208.0/21108.131.208.1 to 108.131.215.254108.131.215.2552,046
124108.131.216.0/21108.131.216.1 to 108.131.223.254108.131.223.2552,046
125108.131.224.0/21108.131.224.1 to 108.131.231.254108.131.231.2552,046
126108.131.232.0/21108.131.232.1 to 108.131.239.254108.131.239.2552,046
127108.131.240.0/21108.131.240.1 to 108.131.247.254108.131.247.2552,046
128108.131.248.0/21108.131.248.1 to 108.131.255.254108.131.255.2552,046
129108.132.0.0/21108.132.0.1 to 108.132.7.254108.132.7.2552,046
130108.132.8.0/21108.132.8.1 to 108.132.15.254108.132.15.2552,046
131108.132.16.0/21108.132.16.1 to 108.132.23.254108.132.23.2552,046
132108.132.24.0/21108.132.24.1 to 108.132.31.254108.132.31.2552,046
133108.132.32.0/21108.132.32.1 to 108.132.39.254108.132.39.2552,046
134108.132.40.0/21108.132.40.1 to 108.132.47.254108.132.47.2552,046
135108.132.48.0/21108.132.48.1 to 108.132.55.254108.132.55.2552,046
136108.132.56.0/21108.132.56.1 to 108.132.63.254108.132.63.2552,046
137108.132.64.0/21108.132.64.1 to 108.132.71.254108.132.71.2552,046
138108.132.72.0/21108.132.72.1 to 108.132.79.254108.132.79.2552,046
139108.132.80.0/21108.132.80.1 to 108.132.87.254108.132.87.2552,046
140108.132.88.0/21108.132.88.1 to 108.132.95.254108.132.95.2552,046
141108.132.96.0/21108.132.96.1 to 108.132.103.254108.132.103.2552,046
142108.132.104.0/21108.132.104.1 to 108.132.111.254108.132.111.2552,046
143108.132.112.0/21108.132.112.1 to 108.132.119.254108.132.119.2552,046
144108.132.120.0/21108.132.120.1 to 108.132.127.254108.132.127.2552,046
145108.132.128.0/21108.132.128.1 to 108.132.135.254108.132.135.2552,046
146108.132.136.0/21108.132.136.1 to 108.132.143.254108.132.143.2552,046
147108.132.144.0/21108.132.144.1 to 108.132.151.254108.132.151.2552,046
148108.132.152.0/21108.132.152.1 to 108.132.159.254108.132.159.2552,046
149108.132.160.0/21108.132.160.1 to 108.132.167.254108.132.167.2552,046
150108.132.168.0/21108.132.168.1 to 108.132.175.254108.132.175.2552,046
151108.132.176.0/21108.132.176.1 to 108.132.183.254108.132.183.2552,046
152108.132.184.0/21108.132.184.1 to 108.132.191.254108.132.191.2552,046
153108.132.192.0/21108.132.192.1 to 108.132.199.254108.132.199.2552,046
154108.132.200.0/21108.132.200.1 to 108.132.207.254108.132.207.2552,046
155108.132.208.0/21108.132.208.1 to 108.132.215.254108.132.215.2552,046
156108.132.216.0/21108.132.216.1 to 108.132.223.254108.132.223.2552,046
157108.132.224.0/21108.132.224.1 to 108.132.231.254108.132.231.2552,046
158108.132.232.0/21108.132.232.1 to 108.132.239.254108.132.239.2552,046
159108.132.240.0/21108.132.240.1 to 108.132.247.254108.132.247.2552,046
160108.132.248.0/21108.132.248.1 to 108.132.255.254108.132.255.2552,046
161108.133.0.0/21108.133.0.1 to 108.133.7.254108.133.7.2552,046
162108.133.8.0/21108.133.8.1 to 108.133.15.254108.133.15.2552,046
163108.133.16.0/21108.133.16.1 to 108.133.23.254108.133.23.2552,046
164108.133.24.0/21108.133.24.1 to 108.133.31.254108.133.31.2552,046
165108.133.32.0/21108.133.32.1 to 108.133.39.254108.133.39.2552,046
166108.133.40.0/21108.133.40.1 to 108.133.47.254108.133.47.2552,046
167108.133.48.0/21108.133.48.1 to 108.133.55.254108.133.55.2552,046
168108.133.56.0/21108.133.56.1 to 108.133.63.254108.133.63.2552,046
169108.133.64.0/21108.133.64.1 to 108.133.71.254108.133.71.2552,046
170108.133.72.0/21108.133.72.1 to 108.133.79.254108.133.79.2552,046
171108.133.80.0/21108.133.80.1 to 108.133.87.254108.133.87.2552,046
172108.133.88.0/21108.133.88.1 to 108.133.95.254108.133.95.2552,046
173108.133.96.0/21108.133.96.1 to 108.133.103.254108.133.103.2552,046
174108.133.104.0/21108.133.104.1 to 108.133.111.254108.133.111.2552,046
175108.133.112.0/21108.133.112.1 to 108.133.119.254108.133.119.2552,046
176108.133.120.0/21108.133.120.1 to 108.133.127.254108.133.127.2552,046
177108.133.128.0/21108.133.128.1 to 108.133.135.254108.133.135.2552,046
178108.133.136.0/21108.133.136.1 to 108.133.143.254108.133.143.2552,046
179108.133.144.0/21108.133.144.1 to 108.133.151.254108.133.151.2552,046
180108.133.152.0/21108.133.152.1 to 108.133.159.254108.133.159.2552,046
181108.133.160.0/21108.133.160.1 to 108.133.167.254108.133.167.2552,046
182108.133.168.0/21108.133.168.1 to 108.133.175.254108.133.175.2552,046
183108.133.176.0/21108.133.176.1 to 108.133.183.254108.133.183.2552,046
184108.133.184.0/21108.133.184.1 to 108.133.191.254108.133.191.2552,046
185108.133.192.0/21108.133.192.1 to 108.133.199.254108.133.199.2552,046
186108.133.200.0/21108.133.200.1 to 108.133.207.254108.133.207.2552,046
187108.133.208.0/21108.133.208.1 to 108.133.215.254108.133.215.2552,046
188108.133.216.0/21108.133.216.1 to 108.133.223.254108.133.223.2552,046
189108.133.224.0/21108.133.224.1 to 108.133.231.254108.133.231.2552,046
190108.133.232.0/21108.133.232.1 to 108.133.239.254108.133.239.2552,046
191108.133.240.0/21108.133.240.1 to 108.133.247.254108.133.247.2552,046
192108.133.248.0/21108.133.248.1 to 108.133.255.254108.133.255.2552,046
193108.134.0.0/21108.134.0.1 to 108.134.7.254108.134.7.2552,046
194108.134.8.0/21108.134.8.1 to 108.134.15.254108.134.15.2552,046
195108.134.16.0/21108.134.16.1 to 108.134.23.254108.134.23.2552,046
196108.134.24.0/21108.134.24.1 to 108.134.31.254108.134.31.2552,046
197108.134.32.0/21108.134.32.1 to 108.134.39.254108.134.39.2552,046
198108.134.40.0/21108.134.40.1 to 108.134.47.254108.134.47.2552,046
199108.134.48.0/21108.134.48.1 to 108.134.55.254108.134.55.2552,046
200108.134.56.0/21108.134.56.1 to 108.134.63.254108.134.63.2552,046
201108.134.64.0/21108.134.64.1 to 108.134.71.254108.134.71.2552,046
202108.134.72.0/21108.134.72.1 to 108.134.79.254108.134.79.2552,046
203108.134.80.0/21108.134.80.1 to 108.134.87.254108.134.87.2552,046
204108.134.88.0/21108.134.88.1 to 108.134.95.254108.134.95.2552,046
205108.134.96.0/21108.134.96.1 to 108.134.103.254108.134.103.2552,046
206108.134.104.0/21108.134.104.1 to 108.134.111.254108.134.111.2552,046
207108.134.112.0/21108.134.112.1 to 108.134.119.254108.134.119.2552,046
208108.134.120.0/21108.134.120.1 to 108.134.127.254108.134.127.2552,046
209108.134.128.0/21108.134.128.1 to 108.134.135.254108.134.135.2552,046
210108.134.136.0/21108.134.136.1 to 108.134.143.254108.134.143.2552,046
211108.134.144.0/21108.134.144.1 to 108.134.151.254108.134.151.2552,046
212108.134.152.0/21108.134.152.1 to 108.134.159.254108.134.159.2552,046
213108.134.160.0/21108.134.160.1 to 108.134.167.254108.134.167.2552,046
214108.134.168.0/21108.134.168.1 to 108.134.175.254108.134.175.2552,046
215108.134.176.0/21108.134.176.1 to 108.134.183.254108.134.183.2552,046
216108.134.184.0/21108.134.184.1 to 108.134.191.254108.134.191.2552,046
217108.134.192.0/21108.134.192.1 to 108.134.199.254108.134.199.2552,046
218108.134.200.0/21108.134.200.1 to 108.134.207.254108.134.207.2552,046
219108.134.208.0/21108.134.208.1 to 108.134.215.254108.134.215.2552,046
220108.134.216.0/21108.134.216.1 to 108.134.223.254108.134.223.2552,046
221108.134.224.0/21108.134.224.1 to 108.134.231.254108.134.231.2552,046
222108.134.232.0/21108.134.232.1 to 108.134.239.254108.134.239.2552,046
223108.134.240.0/21108.134.240.1 to 108.134.247.254108.134.247.2552,046
224108.134.248.0/21108.134.248.1 to 108.134.255.254108.134.255.2552,046
225108.135.0.0/21108.135.0.1 to 108.135.7.254108.135.7.2552,046
226108.135.8.0/21108.135.8.1 to 108.135.15.254108.135.15.2552,046
227108.135.16.0/21108.135.16.1 to 108.135.23.254108.135.23.2552,046
228108.135.24.0/21108.135.24.1 to 108.135.31.254108.135.31.2552,046
229108.135.32.0/21108.135.32.1 to 108.135.39.254108.135.39.2552,046
230108.135.40.0/21108.135.40.1 to 108.135.47.254108.135.47.2552,046
231108.135.48.0/21108.135.48.1 to 108.135.55.254108.135.55.2552,046
232108.135.56.0/21108.135.56.1 to 108.135.63.254108.135.63.2552,046
233108.135.64.0/21108.135.64.1 to 108.135.71.254108.135.71.2552,046
234108.135.72.0/21108.135.72.1 to 108.135.79.254108.135.79.2552,046
235108.135.80.0/21108.135.80.1 to 108.135.87.254108.135.87.2552,046
236108.135.88.0/21108.135.88.1 to 108.135.95.254108.135.95.2552,046
237108.135.96.0/21108.135.96.1 to 108.135.103.254108.135.103.2552,046
238108.135.104.0/21108.135.104.1 to 108.135.111.254108.135.111.2552,046
239108.135.112.0/21108.135.112.1 to 108.135.119.254108.135.119.2552,046
240108.135.120.0/21108.135.120.1 to 108.135.127.254108.135.127.2552,046
241108.135.128.0/21108.135.128.1 to 108.135.135.254108.135.135.2552,046
242108.135.136.0/21108.135.136.1 to 108.135.143.254108.135.143.2552,046
243108.135.144.0/21108.135.144.1 to 108.135.151.254108.135.151.2552,046
244108.135.152.0/21108.135.152.1 to 108.135.159.254108.135.159.2552,046
245108.135.160.0/21108.135.160.1 to 108.135.167.254108.135.167.2552,046
246108.135.168.0/21108.135.168.1 to 108.135.175.254108.135.175.2552,046
247108.135.176.0/21108.135.176.1 to 108.135.183.254108.135.183.2552,046
248108.135.184.0/21108.135.184.1 to 108.135.191.254108.135.191.2552,046
249108.135.192.0/21108.135.192.1 to 108.135.199.254108.135.199.2552,046
250108.135.200.0/21108.135.200.1 to 108.135.207.254108.135.207.2552,046
251108.135.208.0/21108.135.208.1 to 108.135.215.254108.135.215.2552,046
252108.135.216.0/21108.135.216.1 to 108.135.223.254108.135.223.2552,046
253108.135.224.0/21108.135.224.1 to 108.135.231.254108.135.231.2552,046
254108.135.232.0/21108.135.232.1 to 108.135.239.254108.135.239.2552,046
255108.135.240.0/21108.135.240.1 to 108.135.247.254108.135.247.2552,046
256108.135.248.0/21108.135.248.1 to 108.135.255.254108.135.255.2552,046

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.