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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.

Network166.0.0.0/11
Usable hosts2,097,150
Subnet mask255.224.0.0
Addresses2,097,152
Network address
166.0.0.0
Broadcast address
166.31.255.255
First usable
166.0.0.1
Last usable
166.31.255.254
Usable hosts
2,097,150 (2,097,152 less the network and broadcast addresses)
Subnet mask
255.224.0.0
Wildcard mask
0.31.255.255 (Cisco ACLs, OSPF)
Prefix length
/11
Type
Public public
Old class
B (default /16)
As numbers
Hex A6000000 · Integer 2785017856 to 2787115007
Reverse DNS zones
0.166.in-addr.arpa
1.166.in-addr.arpa
2.166.in-addr.arpa
3.166.in-addr.arpa
4.166.in-addr.arpa
5.166.in-addr.arpa
6.166.in-addr.arpa
7.166.in-addr.arpa
8.166.in-addr.arpa
9.166.in-addr.arpa
10.166.in-addr.arpa
11.166.in-addr.arpa
12.166.in-addr.arpa
13.166.in-addr.arpa
14.166.in-addr.arpa
15.166.in-addr.arpa
and 16 more
/11 is not on a 8-bit boundary, so it takes 32 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10100110.00000000.00000000.00000000166.0.0.0
Subnet mask11111111.11100000.00000000.00000000255.224.0.0
Network10100110.00000000.00000000.00000000166.0.0.0
Broadcast10100110.00011111.11111111.11111111166.31.255.255
Split into smaller subnets/21
/12 (2)/13 (4)/14 (8)/15 (16)/16 (32)/17 (64)/18 (128)/19 (256)/20 (512)/21 (1,024)/22 (2,048)/23 (4,096)

166.0.0.0/11 makes 1,024 subnets of /21; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1166.0.0.0/21166.0.0.1 to 166.0.7.254166.0.7.2552,046
2166.0.8.0/21166.0.8.1 to 166.0.15.254166.0.15.2552,046
3166.0.16.0/21166.0.16.1 to 166.0.23.254166.0.23.2552,046
4166.0.24.0/21166.0.24.1 to 166.0.31.254166.0.31.2552,046
5166.0.32.0/21166.0.32.1 to 166.0.39.254166.0.39.2552,046
6166.0.40.0/21166.0.40.1 to 166.0.47.254166.0.47.2552,046
7166.0.48.0/21166.0.48.1 to 166.0.55.254166.0.55.2552,046
8166.0.56.0/21166.0.56.1 to 166.0.63.254166.0.63.2552,046
9166.0.64.0/21166.0.64.1 to 166.0.71.254166.0.71.2552,046
10166.0.72.0/21166.0.72.1 to 166.0.79.254166.0.79.2552,046
11166.0.80.0/21166.0.80.1 to 166.0.87.254166.0.87.2552,046
12166.0.88.0/21166.0.88.1 to 166.0.95.254166.0.95.2552,046
13166.0.96.0/21166.0.96.1 to 166.0.103.254166.0.103.2552,046
14166.0.104.0/21166.0.104.1 to 166.0.111.254166.0.111.2552,046
15166.0.112.0/21166.0.112.1 to 166.0.119.254166.0.119.2552,046
16166.0.120.0/21166.0.120.1 to 166.0.127.254166.0.127.2552,046
17166.0.128.0/21166.0.128.1 to 166.0.135.254166.0.135.2552,046
18166.0.136.0/21166.0.136.1 to 166.0.143.254166.0.143.2552,046
19166.0.144.0/21166.0.144.1 to 166.0.151.254166.0.151.2552,046
20166.0.152.0/21166.0.152.1 to 166.0.159.254166.0.159.2552,046
21166.0.160.0/21166.0.160.1 to 166.0.167.254166.0.167.2552,046
22166.0.168.0/21166.0.168.1 to 166.0.175.254166.0.175.2552,046
23166.0.176.0/21166.0.176.1 to 166.0.183.254166.0.183.2552,046
24166.0.184.0/21166.0.184.1 to 166.0.191.254166.0.191.2552,046
25166.0.192.0/21166.0.192.1 to 166.0.199.254166.0.199.2552,046
26166.0.200.0/21166.0.200.1 to 166.0.207.254166.0.207.2552,046
27166.0.208.0/21166.0.208.1 to 166.0.215.254166.0.215.2552,046
28166.0.216.0/21166.0.216.1 to 166.0.223.254166.0.223.2552,046
29166.0.224.0/21166.0.224.1 to 166.0.231.254166.0.231.2552,046
30166.0.232.0/21166.0.232.1 to 166.0.239.254166.0.239.2552,046
31166.0.240.0/21166.0.240.1 to 166.0.247.254166.0.247.2552,046
32166.0.248.0/21166.0.248.1 to 166.0.255.254166.0.255.2552,046
33166.1.0.0/21166.1.0.1 to 166.1.7.254166.1.7.2552,046
34166.1.8.0/21166.1.8.1 to 166.1.15.254166.1.15.2552,046
35166.1.16.0/21166.1.16.1 to 166.1.23.254166.1.23.2552,046
36166.1.24.0/21166.1.24.1 to 166.1.31.254166.1.31.2552,046
37166.1.32.0/21166.1.32.1 to 166.1.39.254166.1.39.2552,046
38166.1.40.0/21166.1.40.1 to 166.1.47.254166.1.47.2552,046
39166.1.48.0/21166.1.48.1 to 166.1.55.254166.1.55.2552,046
40166.1.56.0/21166.1.56.1 to 166.1.63.254166.1.63.2552,046
41166.1.64.0/21166.1.64.1 to 166.1.71.254166.1.71.2552,046
42166.1.72.0/21166.1.72.1 to 166.1.79.254166.1.79.2552,046
43166.1.80.0/21166.1.80.1 to 166.1.87.254166.1.87.2552,046
44166.1.88.0/21166.1.88.1 to 166.1.95.254166.1.95.2552,046
45166.1.96.0/21166.1.96.1 to 166.1.103.254166.1.103.2552,046
46166.1.104.0/21166.1.104.1 to 166.1.111.254166.1.111.2552,046
47166.1.112.0/21166.1.112.1 to 166.1.119.254166.1.119.2552,046
48166.1.120.0/21166.1.120.1 to 166.1.127.254166.1.127.2552,046
49166.1.128.0/21166.1.128.1 to 166.1.135.254166.1.135.2552,046
50166.1.136.0/21166.1.136.1 to 166.1.143.254166.1.143.2552,046
51166.1.144.0/21166.1.144.1 to 166.1.151.254166.1.151.2552,046
52166.1.152.0/21166.1.152.1 to 166.1.159.254166.1.159.2552,046
53166.1.160.0/21166.1.160.1 to 166.1.167.254166.1.167.2552,046
54166.1.168.0/21166.1.168.1 to 166.1.175.254166.1.175.2552,046
55166.1.176.0/21166.1.176.1 to 166.1.183.254166.1.183.2552,046
56166.1.184.0/21166.1.184.1 to 166.1.191.254166.1.191.2552,046
57166.1.192.0/21166.1.192.1 to 166.1.199.254166.1.199.2552,046
58166.1.200.0/21166.1.200.1 to 166.1.207.254166.1.207.2552,046
59166.1.208.0/21166.1.208.1 to 166.1.215.254166.1.215.2552,046
60166.1.216.0/21166.1.216.1 to 166.1.223.254166.1.223.2552,046
61166.1.224.0/21166.1.224.1 to 166.1.231.254166.1.231.2552,046
62166.1.232.0/21166.1.232.1 to 166.1.239.254166.1.239.2552,046
63166.1.240.0/21166.1.240.1 to 166.1.247.254166.1.247.2552,046
64166.1.248.0/21166.1.248.1 to 166.1.255.254166.1.255.2552,046
65166.2.0.0/21166.2.0.1 to 166.2.7.254166.2.7.2552,046
66166.2.8.0/21166.2.8.1 to 166.2.15.254166.2.15.2552,046
67166.2.16.0/21166.2.16.1 to 166.2.23.254166.2.23.2552,046
68166.2.24.0/21166.2.24.1 to 166.2.31.254166.2.31.2552,046
69166.2.32.0/21166.2.32.1 to 166.2.39.254166.2.39.2552,046
70166.2.40.0/21166.2.40.1 to 166.2.47.254166.2.47.2552,046
71166.2.48.0/21166.2.48.1 to 166.2.55.254166.2.55.2552,046
72166.2.56.0/21166.2.56.1 to 166.2.63.254166.2.63.2552,046
73166.2.64.0/21166.2.64.1 to 166.2.71.254166.2.71.2552,046
74166.2.72.0/21166.2.72.1 to 166.2.79.254166.2.79.2552,046
75166.2.80.0/21166.2.80.1 to 166.2.87.254166.2.87.2552,046
76166.2.88.0/21166.2.88.1 to 166.2.95.254166.2.95.2552,046
77166.2.96.0/21166.2.96.1 to 166.2.103.254166.2.103.2552,046
78166.2.104.0/21166.2.104.1 to 166.2.111.254166.2.111.2552,046
79166.2.112.0/21166.2.112.1 to 166.2.119.254166.2.119.2552,046
80166.2.120.0/21166.2.120.1 to 166.2.127.254166.2.127.2552,046
81166.2.128.0/21166.2.128.1 to 166.2.135.254166.2.135.2552,046
82166.2.136.0/21166.2.136.1 to 166.2.143.254166.2.143.2552,046
83166.2.144.0/21166.2.144.1 to 166.2.151.254166.2.151.2552,046
84166.2.152.0/21166.2.152.1 to 166.2.159.254166.2.159.2552,046
85166.2.160.0/21166.2.160.1 to 166.2.167.254166.2.167.2552,046
86166.2.168.0/21166.2.168.1 to 166.2.175.254166.2.175.2552,046
87166.2.176.0/21166.2.176.1 to 166.2.183.254166.2.183.2552,046
88166.2.184.0/21166.2.184.1 to 166.2.191.254166.2.191.2552,046
89166.2.192.0/21166.2.192.1 to 166.2.199.254166.2.199.2552,046
90166.2.200.0/21166.2.200.1 to 166.2.207.254166.2.207.2552,046
91166.2.208.0/21166.2.208.1 to 166.2.215.254166.2.215.2552,046
92166.2.216.0/21166.2.216.1 to 166.2.223.254166.2.223.2552,046
93166.2.224.0/21166.2.224.1 to 166.2.231.254166.2.231.2552,046
94166.2.232.0/21166.2.232.1 to 166.2.239.254166.2.239.2552,046
95166.2.240.0/21166.2.240.1 to 166.2.247.254166.2.247.2552,046
96166.2.248.0/21166.2.248.1 to 166.2.255.254166.2.255.2552,046
97166.3.0.0/21166.3.0.1 to 166.3.7.254166.3.7.2552,046
98166.3.8.0/21166.3.8.1 to 166.3.15.254166.3.15.2552,046
99166.3.16.0/21166.3.16.1 to 166.3.23.254166.3.23.2552,046
100166.3.24.0/21166.3.24.1 to 166.3.31.254166.3.31.2552,046
101166.3.32.0/21166.3.32.1 to 166.3.39.254166.3.39.2552,046
102166.3.40.0/21166.3.40.1 to 166.3.47.254166.3.47.2552,046
103166.3.48.0/21166.3.48.1 to 166.3.55.254166.3.55.2552,046
104166.3.56.0/21166.3.56.1 to 166.3.63.254166.3.63.2552,046
105166.3.64.0/21166.3.64.1 to 166.3.71.254166.3.71.2552,046
106166.3.72.0/21166.3.72.1 to 166.3.79.254166.3.79.2552,046
107166.3.80.0/21166.3.80.1 to 166.3.87.254166.3.87.2552,046
108166.3.88.0/21166.3.88.1 to 166.3.95.254166.3.95.2552,046
109166.3.96.0/21166.3.96.1 to 166.3.103.254166.3.103.2552,046
110166.3.104.0/21166.3.104.1 to 166.3.111.254166.3.111.2552,046
111166.3.112.0/21166.3.112.1 to 166.3.119.254166.3.119.2552,046
112166.3.120.0/21166.3.120.1 to 166.3.127.254166.3.127.2552,046
113166.3.128.0/21166.3.128.1 to 166.3.135.254166.3.135.2552,046
114166.3.136.0/21166.3.136.1 to 166.3.143.254166.3.143.2552,046
115166.3.144.0/21166.3.144.1 to 166.3.151.254166.3.151.2552,046
116166.3.152.0/21166.3.152.1 to 166.3.159.254166.3.159.2552,046
117166.3.160.0/21166.3.160.1 to 166.3.167.254166.3.167.2552,046
118166.3.168.0/21166.3.168.1 to 166.3.175.254166.3.175.2552,046
119166.3.176.0/21166.3.176.1 to 166.3.183.254166.3.183.2552,046
120166.3.184.0/21166.3.184.1 to 166.3.191.254166.3.191.2552,046
121166.3.192.0/21166.3.192.1 to 166.3.199.254166.3.199.2552,046
122166.3.200.0/21166.3.200.1 to 166.3.207.254166.3.207.2552,046
123166.3.208.0/21166.3.208.1 to 166.3.215.254166.3.215.2552,046
124166.3.216.0/21166.3.216.1 to 166.3.223.254166.3.223.2552,046
125166.3.224.0/21166.3.224.1 to 166.3.231.254166.3.231.2552,046
126166.3.232.0/21166.3.232.1 to 166.3.239.254166.3.239.2552,046
127166.3.240.0/21166.3.240.1 to 166.3.247.254166.3.247.2552,046
128166.3.248.0/21166.3.248.1 to 166.3.255.254166.3.255.2552,046
129166.4.0.0/21166.4.0.1 to 166.4.7.254166.4.7.2552,046
130166.4.8.0/21166.4.8.1 to 166.4.15.254166.4.15.2552,046
131166.4.16.0/21166.4.16.1 to 166.4.23.254166.4.23.2552,046
132166.4.24.0/21166.4.24.1 to 166.4.31.254166.4.31.2552,046
133166.4.32.0/21166.4.32.1 to 166.4.39.254166.4.39.2552,046
134166.4.40.0/21166.4.40.1 to 166.4.47.254166.4.47.2552,046
135166.4.48.0/21166.4.48.1 to 166.4.55.254166.4.55.2552,046
136166.4.56.0/21166.4.56.1 to 166.4.63.254166.4.63.2552,046
137166.4.64.0/21166.4.64.1 to 166.4.71.254166.4.71.2552,046
138166.4.72.0/21166.4.72.1 to 166.4.79.254166.4.79.2552,046
139166.4.80.0/21166.4.80.1 to 166.4.87.254166.4.87.2552,046
140166.4.88.0/21166.4.88.1 to 166.4.95.254166.4.95.2552,046
141166.4.96.0/21166.4.96.1 to 166.4.103.254166.4.103.2552,046
142166.4.104.0/21166.4.104.1 to 166.4.111.254166.4.111.2552,046
143166.4.112.0/21166.4.112.1 to 166.4.119.254166.4.119.2552,046
144166.4.120.0/21166.4.120.1 to 166.4.127.254166.4.127.2552,046
145166.4.128.0/21166.4.128.1 to 166.4.135.254166.4.135.2552,046
146166.4.136.0/21166.4.136.1 to 166.4.143.254166.4.143.2552,046
147166.4.144.0/21166.4.144.1 to 166.4.151.254166.4.151.2552,046
148166.4.152.0/21166.4.152.1 to 166.4.159.254166.4.159.2552,046
149166.4.160.0/21166.4.160.1 to 166.4.167.254166.4.167.2552,046
150166.4.168.0/21166.4.168.1 to 166.4.175.254166.4.175.2552,046
151166.4.176.0/21166.4.176.1 to 166.4.183.254166.4.183.2552,046
152166.4.184.0/21166.4.184.1 to 166.4.191.254166.4.191.2552,046
153166.4.192.0/21166.4.192.1 to 166.4.199.254166.4.199.2552,046
154166.4.200.0/21166.4.200.1 to 166.4.207.254166.4.207.2552,046
155166.4.208.0/21166.4.208.1 to 166.4.215.254166.4.215.2552,046
156166.4.216.0/21166.4.216.1 to 166.4.223.254166.4.223.2552,046
157166.4.224.0/21166.4.224.1 to 166.4.231.254166.4.231.2552,046
158166.4.232.0/21166.4.232.1 to 166.4.239.254166.4.239.2552,046
159166.4.240.0/21166.4.240.1 to 166.4.247.254166.4.247.2552,046
160166.4.248.0/21166.4.248.1 to 166.4.255.254166.4.255.2552,046
161166.5.0.0/21166.5.0.1 to 166.5.7.254166.5.7.2552,046
162166.5.8.0/21166.5.8.1 to 166.5.15.254166.5.15.2552,046
163166.5.16.0/21166.5.16.1 to 166.5.23.254166.5.23.2552,046
164166.5.24.0/21166.5.24.1 to 166.5.31.254166.5.31.2552,046
165166.5.32.0/21166.5.32.1 to 166.5.39.254166.5.39.2552,046
166166.5.40.0/21166.5.40.1 to 166.5.47.254166.5.47.2552,046
167166.5.48.0/21166.5.48.1 to 166.5.55.254166.5.55.2552,046
168166.5.56.0/21166.5.56.1 to 166.5.63.254166.5.63.2552,046
169166.5.64.0/21166.5.64.1 to 166.5.71.254166.5.71.2552,046
170166.5.72.0/21166.5.72.1 to 166.5.79.254166.5.79.2552,046
171166.5.80.0/21166.5.80.1 to 166.5.87.254166.5.87.2552,046
172166.5.88.0/21166.5.88.1 to 166.5.95.254166.5.95.2552,046
173166.5.96.0/21166.5.96.1 to 166.5.103.254166.5.103.2552,046
174166.5.104.0/21166.5.104.1 to 166.5.111.254166.5.111.2552,046
175166.5.112.0/21166.5.112.1 to 166.5.119.254166.5.119.2552,046
176166.5.120.0/21166.5.120.1 to 166.5.127.254166.5.127.2552,046
177166.5.128.0/21166.5.128.1 to 166.5.135.254166.5.135.2552,046
178166.5.136.0/21166.5.136.1 to 166.5.143.254166.5.143.2552,046
179166.5.144.0/21166.5.144.1 to 166.5.151.254166.5.151.2552,046
180166.5.152.0/21166.5.152.1 to 166.5.159.254166.5.159.2552,046
181166.5.160.0/21166.5.160.1 to 166.5.167.254166.5.167.2552,046
182166.5.168.0/21166.5.168.1 to 166.5.175.254166.5.175.2552,046
183166.5.176.0/21166.5.176.1 to 166.5.183.254166.5.183.2552,046
184166.5.184.0/21166.5.184.1 to 166.5.191.254166.5.191.2552,046
185166.5.192.0/21166.5.192.1 to 166.5.199.254166.5.199.2552,046
186166.5.200.0/21166.5.200.1 to 166.5.207.254166.5.207.2552,046
187166.5.208.0/21166.5.208.1 to 166.5.215.254166.5.215.2552,046
188166.5.216.0/21166.5.216.1 to 166.5.223.254166.5.223.2552,046
189166.5.224.0/21166.5.224.1 to 166.5.231.254166.5.231.2552,046
190166.5.232.0/21166.5.232.1 to 166.5.239.254166.5.239.2552,046
191166.5.240.0/21166.5.240.1 to 166.5.247.254166.5.247.2552,046
192166.5.248.0/21166.5.248.1 to 166.5.255.254166.5.255.2552,046
193166.6.0.0/21166.6.0.1 to 166.6.7.254166.6.7.2552,046
194166.6.8.0/21166.6.8.1 to 166.6.15.254166.6.15.2552,046
195166.6.16.0/21166.6.16.1 to 166.6.23.254166.6.23.2552,046
196166.6.24.0/21166.6.24.1 to 166.6.31.254166.6.31.2552,046
197166.6.32.0/21166.6.32.1 to 166.6.39.254166.6.39.2552,046
198166.6.40.0/21166.6.40.1 to 166.6.47.254166.6.47.2552,046
199166.6.48.0/21166.6.48.1 to 166.6.55.254166.6.55.2552,046
200166.6.56.0/21166.6.56.1 to 166.6.63.254166.6.63.2552,046
201166.6.64.0/21166.6.64.1 to 166.6.71.254166.6.71.2552,046
202166.6.72.0/21166.6.72.1 to 166.6.79.254166.6.79.2552,046
203166.6.80.0/21166.6.80.1 to 166.6.87.254166.6.87.2552,046
204166.6.88.0/21166.6.88.1 to 166.6.95.254166.6.95.2552,046
205166.6.96.0/21166.6.96.1 to 166.6.103.254166.6.103.2552,046
206166.6.104.0/21166.6.104.1 to 166.6.111.254166.6.111.2552,046
207166.6.112.0/21166.6.112.1 to 166.6.119.254166.6.119.2552,046
208166.6.120.0/21166.6.120.1 to 166.6.127.254166.6.127.2552,046
209166.6.128.0/21166.6.128.1 to 166.6.135.254166.6.135.2552,046
210166.6.136.0/21166.6.136.1 to 166.6.143.254166.6.143.2552,046
211166.6.144.0/21166.6.144.1 to 166.6.151.254166.6.151.2552,046
212166.6.152.0/21166.6.152.1 to 166.6.159.254166.6.159.2552,046
213166.6.160.0/21166.6.160.1 to 166.6.167.254166.6.167.2552,046
214166.6.168.0/21166.6.168.1 to 166.6.175.254166.6.175.2552,046
215166.6.176.0/21166.6.176.1 to 166.6.183.254166.6.183.2552,046
216166.6.184.0/21166.6.184.1 to 166.6.191.254166.6.191.2552,046
217166.6.192.0/21166.6.192.1 to 166.6.199.254166.6.199.2552,046
218166.6.200.0/21166.6.200.1 to 166.6.207.254166.6.207.2552,046
219166.6.208.0/21166.6.208.1 to 166.6.215.254166.6.215.2552,046
220166.6.216.0/21166.6.216.1 to 166.6.223.254166.6.223.2552,046
221166.6.224.0/21166.6.224.1 to 166.6.231.254166.6.231.2552,046
222166.6.232.0/21166.6.232.1 to 166.6.239.254166.6.239.2552,046
223166.6.240.0/21166.6.240.1 to 166.6.247.254166.6.247.2552,046
224166.6.248.0/21166.6.248.1 to 166.6.255.254166.6.255.2552,046
225166.7.0.0/21166.7.0.1 to 166.7.7.254166.7.7.2552,046
226166.7.8.0/21166.7.8.1 to 166.7.15.254166.7.15.2552,046
227166.7.16.0/21166.7.16.1 to 166.7.23.254166.7.23.2552,046
228166.7.24.0/21166.7.24.1 to 166.7.31.254166.7.31.2552,046
229166.7.32.0/21166.7.32.1 to 166.7.39.254166.7.39.2552,046
230166.7.40.0/21166.7.40.1 to 166.7.47.254166.7.47.2552,046
231166.7.48.0/21166.7.48.1 to 166.7.55.254166.7.55.2552,046
232166.7.56.0/21166.7.56.1 to 166.7.63.254166.7.63.2552,046
233166.7.64.0/21166.7.64.1 to 166.7.71.254166.7.71.2552,046
234166.7.72.0/21166.7.72.1 to 166.7.79.254166.7.79.2552,046
235166.7.80.0/21166.7.80.1 to 166.7.87.254166.7.87.2552,046
236166.7.88.0/21166.7.88.1 to 166.7.95.254166.7.95.2552,046
237166.7.96.0/21166.7.96.1 to 166.7.103.254166.7.103.2552,046
238166.7.104.0/21166.7.104.1 to 166.7.111.254166.7.111.2552,046
239166.7.112.0/21166.7.112.1 to 166.7.119.254166.7.119.2552,046
240166.7.120.0/21166.7.120.1 to 166.7.127.254166.7.127.2552,046
241166.7.128.0/21166.7.128.1 to 166.7.135.254166.7.135.2552,046
242166.7.136.0/21166.7.136.1 to 166.7.143.254166.7.143.2552,046
243166.7.144.0/21166.7.144.1 to 166.7.151.254166.7.151.2552,046
244166.7.152.0/21166.7.152.1 to 166.7.159.254166.7.159.2552,046
245166.7.160.0/21166.7.160.1 to 166.7.167.254166.7.167.2552,046
246166.7.168.0/21166.7.168.1 to 166.7.175.254166.7.175.2552,046
247166.7.176.0/21166.7.176.1 to 166.7.183.254166.7.183.2552,046
248166.7.184.0/21166.7.184.1 to 166.7.191.254166.7.191.2552,046
249166.7.192.0/21166.7.192.1 to 166.7.199.254166.7.199.2552,046
250166.7.200.0/21166.7.200.1 to 166.7.207.254166.7.207.2552,046
251166.7.208.0/21166.7.208.1 to 166.7.215.254166.7.215.2552,046
252166.7.216.0/21166.7.216.1 to 166.7.223.254166.7.223.2552,046
253166.7.224.0/21166.7.224.1 to 166.7.231.254166.7.231.2552,046
254166.7.232.0/21166.7.232.1 to 166.7.239.254166.7.239.2552,046
255166.7.240.0/21166.7.240.1 to 166.7.247.254166.7.247.2552,046
256166.7.248.0/21166.7.248.1 to 166.7.255.254166.7.255.2552,046

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.