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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.

Network168.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
168.0.0.0
Broadcast address
168.255.255.255
First usable
168.0.0.1
Last usable
168.255.255.254
Usable hosts
16,777,214 (16,777,216 less the network and broadcast addresses)
Subnet mask
255.0.0.0
Wildcard mask
0.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/8
Type
Public public
Old class
B (default /16)
As numbers
Hex A8000000 · Integer 2818572288 to 2835349503
Reverse DNS zone
168.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10101000..00000000.00000000.00000000168.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network10101000..00000000.00000000.00000000168.0.0.0
Broadcast10101000..11111111.11111111.11111111168.255.255.255
Split into smaller subnets/20
/9 (2)/10 (4)/11 (8)/12 (16)/13 (32)/14 (64)/15 (128)/16 (256)/17 (512)/18 (1,024)/19 (2,048)/20 (4,096)

168.0.0.0/8 makes 4,096 subnets of /20; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1168.0.0.0/20168.0.0.1 to 168.0.15.254168.0.15.2554,094
2168.0.16.0/20168.0.16.1 to 168.0.31.254168.0.31.2554,094
3168.0.32.0/20168.0.32.1 to 168.0.47.254168.0.47.2554,094
4168.0.48.0/20168.0.48.1 to 168.0.63.254168.0.63.2554,094
5168.0.64.0/20168.0.64.1 to 168.0.79.254168.0.79.2554,094
6168.0.80.0/20168.0.80.1 to 168.0.95.254168.0.95.2554,094
7168.0.96.0/20168.0.96.1 to 168.0.111.254168.0.111.2554,094
8168.0.112.0/20168.0.112.1 to 168.0.127.254168.0.127.2554,094
9168.0.128.0/20168.0.128.1 to 168.0.143.254168.0.143.2554,094
10168.0.144.0/20168.0.144.1 to 168.0.159.254168.0.159.2554,094
11168.0.160.0/20168.0.160.1 to 168.0.175.254168.0.175.2554,094
12168.0.176.0/20168.0.176.1 to 168.0.191.254168.0.191.2554,094
13168.0.192.0/20168.0.192.1 to 168.0.207.254168.0.207.2554,094
14168.0.208.0/20168.0.208.1 to 168.0.223.254168.0.223.2554,094
15168.0.224.0/20168.0.224.1 to 168.0.239.254168.0.239.2554,094
16168.0.240.0/20168.0.240.1 to 168.0.255.254168.0.255.2554,094
17168.1.0.0/20168.1.0.1 to 168.1.15.254168.1.15.2554,094
18168.1.16.0/20168.1.16.1 to 168.1.31.254168.1.31.2554,094
19168.1.32.0/20168.1.32.1 to 168.1.47.254168.1.47.2554,094
20168.1.48.0/20168.1.48.1 to 168.1.63.254168.1.63.2554,094
21168.1.64.0/20168.1.64.1 to 168.1.79.254168.1.79.2554,094
22168.1.80.0/20168.1.80.1 to 168.1.95.254168.1.95.2554,094
23168.1.96.0/20168.1.96.1 to 168.1.111.254168.1.111.2554,094
24168.1.112.0/20168.1.112.1 to 168.1.127.254168.1.127.2554,094
25168.1.128.0/20168.1.128.1 to 168.1.143.254168.1.143.2554,094
26168.1.144.0/20168.1.144.1 to 168.1.159.254168.1.159.2554,094
27168.1.160.0/20168.1.160.1 to 168.1.175.254168.1.175.2554,094
28168.1.176.0/20168.1.176.1 to 168.1.191.254168.1.191.2554,094
29168.1.192.0/20168.1.192.1 to 168.1.207.254168.1.207.2554,094
30168.1.208.0/20168.1.208.1 to 168.1.223.254168.1.223.2554,094
31168.1.224.0/20168.1.224.1 to 168.1.239.254168.1.239.2554,094
32168.1.240.0/20168.1.240.1 to 168.1.255.254168.1.255.2554,094
33168.2.0.0/20168.2.0.1 to 168.2.15.254168.2.15.2554,094
34168.2.16.0/20168.2.16.1 to 168.2.31.254168.2.31.2554,094
35168.2.32.0/20168.2.32.1 to 168.2.47.254168.2.47.2554,094
36168.2.48.0/20168.2.48.1 to 168.2.63.254168.2.63.2554,094
37168.2.64.0/20168.2.64.1 to 168.2.79.254168.2.79.2554,094
38168.2.80.0/20168.2.80.1 to 168.2.95.254168.2.95.2554,094
39168.2.96.0/20168.2.96.1 to 168.2.111.254168.2.111.2554,094
40168.2.112.0/20168.2.112.1 to 168.2.127.254168.2.127.2554,094
41168.2.128.0/20168.2.128.1 to 168.2.143.254168.2.143.2554,094
42168.2.144.0/20168.2.144.1 to 168.2.159.254168.2.159.2554,094
43168.2.160.0/20168.2.160.1 to 168.2.175.254168.2.175.2554,094
44168.2.176.0/20168.2.176.1 to 168.2.191.254168.2.191.2554,094
45168.2.192.0/20168.2.192.1 to 168.2.207.254168.2.207.2554,094
46168.2.208.0/20168.2.208.1 to 168.2.223.254168.2.223.2554,094
47168.2.224.0/20168.2.224.1 to 168.2.239.254168.2.239.2554,094
48168.2.240.0/20168.2.240.1 to 168.2.255.254168.2.255.2554,094
49168.3.0.0/20168.3.0.1 to 168.3.15.254168.3.15.2554,094
50168.3.16.0/20168.3.16.1 to 168.3.31.254168.3.31.2554,094
51168.3.32.0/20168.3.32.1 to 168.3.47.254168.3.47.2554,094
52168.3.48.0/20168.3.48.1 to 168.3.63.254168.3.63.2554,094
53168.3.64.0/20168.3.64.1 to 168.3.79.254168.3.79.2554,094
54168.3.80.0/20168.3.80.1 to 168.3.95.254168.3.95.2554,094
55168.3.96.0/20168.3.96.1 to 168.3.111.254168.3.111.2554,094
56168.3.112.0/20168.3.112.1 to 168.3.127.254168.3.127.2554,094
57168.3.128.0/20168.3.128.1 to 168.3.143.254168.3.143.2554,094
58168.3.144.0/20168.3.144.1 to 168.3.159.254168.3.159.2554,094
59168.3.160.0/20168.3.160.1 to 168.3.175.254168.3.175.2554,094
60168.3.176.0/20168.3.176.1 to 168.3.191.254168.3.191.2554,094
61168.3.192.0/20168.3.192.1 to 168.3.207.254168.3.207.2554,094
62168.3.208.0/20168.3.208.1 to 168.3.223.254168.3.223.2554,094
63168.3.224.0/20168.3.224.1 to 168.3.239.254168.3.239.2554,094
64168.3.240.0/20168.3.240.1 to 168.3.255.254168.3.255.2554,094
65168.4.0.0/20168.4.0.1 to 168.4.15.254168.4.15.2554,094
66168.4.16.0/20168.4.16.1 to 168.4.31.254168.4.31.2554,094
67168.4.32.0/20168.4.32.1 to 168.4.47.254168.4.47.2554,094
68168.4.48.0/20168.4.48.1 to 168.4.63.254168.4.63.2554,094
69168.4.64.0/20168.4.64.1 to 168.4.79.254168.4.79.2554,094
70168.4.80.0/20168.4.80.1 to 168.4.95.254168.4.95.2554,094
71168.4.96.0/20168.4.96.1 to 168.4.111.254168.4.111.2554,094
72168.4.112.0/20168.4.112.1 to 168.4.127.254168.4.127.2554,094
73168.4.128.0/20168.4.128.1 to 168.4.143.254168.4.143.2554,094
74168.4.144.0/20168.4.144.1 to 168.4.159.254168.4.159.2554,094
75168.4.160.0/20168.4.160.1 to 168.4.175.254168.4.175.2554,094
76168.4.176.0/20168.4.176.1 to 168.4.191.254168.4.191.2554,094
77168.4.192.0/20168.4.192.1 to 168.4.207.254168.4.207.2554,094
78168.4.208.0/20168.4.208.1 to 168.4.223.254168.4.223.2554,094
79168.4.224.0/20168.4.224.1 to 168.4.239.254168.4.239.2554,094
80168.4.240.0/20168.4.240.1 to 168.4.255.254168.4.255.2554,094
81168.5.0.0/20168.5.0.1 to 168.5.15.254168.5.15.2554,094
82168.5.16.0/20168.5.16.1 to 168.5.31.254168.5.31.2554,094
83168.5.32.0/20168.5.32.1 to 168.5.47.254168.5.47.2554,094
84168.5.48.0/20168.5.48.1 to 168.5.63.254168.5.63.2554,094
85168.5.64.0/20168.5.64.1 to 168.5.79.254168.5.79.2554,094
86168.5.80.0/20168.5.80.1 to 168.5.95.254168.5.95.2554,094
87168.5.96.0/20168.5.96.1 to 168.5.111.254168.5.111.2554,094
88168.5.112.0/20168.5.112.1 to 168.5.127.254168.5.127.2554,094
89168.5.128.0/20168.5.128.1 to 168.5.143.254168.5.143.2554,094
90168.5.144.0/20168.5.144.1 to 168.5.159.254168.5.159.2554,094
91168.5.160.0/20168.5.160.1 to 168.5.175.254168.5.175.2554,094
92168.5.176.0/20168.5.176.1 to 168.5.191.254168.5.191.2554,094
93168.5.192.0/20168.5.192.1 to 168.5.207.254168.5.207.2554,094
94168.5.208.0/20168.5.208.1 to 168.5.223.254168.5.223.2554,094
95168.5.224.0/20168.5.224.1 to 168.5.239.254168.5.239.2554,094
96168.5.240.0/20168.5.240.1 to 168.5.255.254168.5.255.2554,094
97168.6.0.0/20168.6.0.1 to 168.6.15.254168.6.15.2554,094
98168.6.16.0/20168.6.16.1 to 168.6.31.254168.6.31.2554,094
99168.6.32.0/20168.6.32.1 to 168.6.47.254168.6.47.2554,094
100168.6.48.0/20168.6.48.1 to 168.6.63.254168.6.63.2554,094
101168.6.64.0/20168.6.64.1 to 168.6.79.254168.6.79.2554,094
102168.6.80.0/20168.6.80.1 to 168.6.95.254168.6.95.2554,094
103168.6.96.0/20168.6.96.1 to 168.6.111.254168.6.111.2554,094
104168.6.112.0/20168.6.112.1 to 168.6.127.254168.6.127.2554,094
105168.6.128.0/20168.6.128.1 to 168.6.143.254168.6.143.2554,094
106168.6.144.0/20168.6.144.1 to 168.6.159.254168.6.159.2554,094
107168.6.160.0/20168.6.160.1 to 168.6.175.254168.6.175.2554,094
108168.6.176.0/20168.6.176.1 to 168.6.191.254168.6.191.2554,094
109168.6.192.0/20168.6.192.1 to 168.6.207.254168.6.207.2554,094
110168.6.208.0/20168.6.208.1 to 168.6.223.254168.6.223.2554,094
111168.6.224.0/20168.6.224.1 to 168.6.239.254168.6.239.2554,094
112168.6.240.0/20168.6.240.1 to 168.6.255.254168.6.255.2554,094
113168.7.0.0/20168.7.0.1 to 168.7.15.254168.7.15.2554,094
114168.7.16.0/20168.7.16.1 to 168.7.31.254168.7.31.2554,094
115168.7.32.0/20168.7.32.1 to 168.7.47.254168.7.47.2554,094
116168.7.48.0/20168.7.48.1 to 168.7.63.254168.7.63.2554,094
117168.7.64.0/20168.7.64.1 to 168.7.79.254168.7.79.2554,094
118168.7.80.0/20168.7.80.1 to 168.7.95.254168.7.95.2554,094
119168.7.96.0/20168.7.96.1 to 168.7.111.254168.7.111.2554,094
120168.7.112.0/20168.7.112.1 to 168.7.127.254168.7.127.2554,094
121168.7.128.0/20168.7.128.1 to 168.7.143.254168.7.143.2554,094
122168.7.144.0/20168.7.144.1 to 168.7.159.254168.7.159.2554,094
123168.7.160.0/20168.7.160.1 to 168.7.175.254168.7.175.2554,094
124168.7.176.0/20168.7.176.1 to 168.7.191.254168.7.191.2554,094
125168.7.192.0/20168.7.192.1 to 168.7.207.254168.7.207.2554,094
126168.7.208.0/20168.7.208.1 to 168.7.223.254168.7.223.2554,094
127168.7.224.0/20168.7.224.1 to 168.7.239.254168.7.239.2554,094
128168.7.240.0/20168.7.240.1 to 168.7.255.254168.7.255.2554,094
129168.8.0.0/20168.8.0.1 to 168.8.15.254168.8.15.2554,094
130168.8.16.0/20168.8.16.1 to 168.8.31.254168.8.31.2554,094
131168.8.32.0/20168.8.32.1 to 168.8.47.254168.8.47.2554,094
132168.8.48.0/20168.8.48.1 to 168.8.63.254168.8.63.2554,094
133168.8.64.0/20168.8.64.1 to 168.8.79.254168.8.79.2554,094
134168.8.80.0/20168.8.80.1 to 168.8.95.254168.8.95.2554,094
135168.8.96.0/20168.8.96.1 to 168.8.111.254168.8.111.2554,094
136168.8.112.0/20168.8.112.1 to 168.8.127.254168.8.127.2554,094
137168.8.128.0/20168.8.128.1 to 168.8.143.254168.8.143.2554,094
138168.8.144.0/20168.8.144.1 to 168.8.159.254168.8.159.2554,094
139168.8.160.0/20168.8.160.1 to 168.8.175.254168.8.175.2554,094
140168.8.176.0/20168.8.176.1 to 168.8.191.254168.8.191.2554,094
141168.8.192.0/20168.8.192.1 to 168.8.207.254168.8.207.2554,094
142168.8.208.0/20168.8.208.1 to 168.8.223.254168.8.223.2554,094
143168.8.224.0/20168.8.224.1 to 168.8.239.254168.8.239.2554,094
144168.8.240.0/20168.8.240.1 to 168.8.255.254168.8.255.2554,094
145168.9.0.0/20168.9.0.1 to 168.9.15.254168.9.15.2554,094
146168.9.16.0/20168.9.16.1 to 168.9.31.254168.9.31.2554,094
147168.9.32.0/20168.9.32.1 to 168.9.47.254168.9.47.2554,094
148168.9.48.0/20168.9.48.1 to 168.9.63.254168.9.63.2554,094
149168.9.64.0/20168.9.64.1 to 168.9.79.254168.9.79.2554,094
150168.9.80.0/20168.9.80.1 to 168.9.95.254168.9.95.2554,094
151168.9.96.0/20168.9.96.1 to 168.9.111.254168.9.111.2554,094
152168.9.112.0/20168.9.112.1 to 168.9.127.254168.9.127.2554,094
153168.9.128.0/20168.9.128.1 to 168.9.143.254168.9.143.2554,094
154168.9.144.0/20168.9.144.1 to 168.9.159.254168.9.159.2554,094
155168.9.160.0/20168.9.160.1 to 168.9.175.254168.9.175.2554,094
156168.9.176.0/20168.9.176.1 to 168.9.191.254168.9.191.2554,094
157168.9.192.0/20168.9.192.1 to 168.9.207.254168.9.207.2554,094
158168.9.208.0/20168.9.208.1 to 168.9.223.254168.9.223.2554,094
159168.9.224.0/20168.9.224.1 to 168.9.239.254168.9.239.2554,094
160168.9.240.0/20168.9.240.1 to 168.9.255.254168.9.255.2554,094
161168.10.0.0/20168.10.0.1 to 168.10.15.254168.10.15.2554,094
162168.10.16.0/20168.10.16.1 to 168.10.31.254168.10.31.2554,094
163168.10.32.0/20168.10.32.1 to 168.10.47.254168.10.47.2554,094
164168.10.48.0/20168.10.48.1 to 168.10.63.254168.10.63.2554,094
165168.10.64.0/20168.10.64.1 to 168.10.79.254168.10.79.2554,094
166168.10.80.0/20168.10.80.1 to 168.10.95.254168.10.95.2554,094
167168.10.96.0/20168.10.96.1 to 168.10.111.254168.10.111.2554,094
168168.10.112.0/20168.10.112.1 to 168.10.127.254168.10.127.2554,094
169168.10.128.0/20168.10.128.1 to 168.10.143.254168.10.143.2554,094
170168.10.144.0/20168.10.144.1 to 168.10.159.254168.10.159.2554,094
171168.10.160.0/20168.10.160.1 to 168.10.175.254168.10.175.2554,094
172168.10.176.0/20168.10.176.1 to 168.10.191.254168.10.191.2554,094
173168.10.192.0/20168.10.192.1 to 168.10.207.254168.10.207.2554,094
174168.10.208.0/20168.10.208.1 to 168.10.223.254168.10.223.2554,094
175168.10.224.0/20168.10.224.1 to 168.10.239.254168.10.239.2554,094
176168.10.240.0/20168.10.240.1 to 168.10.255.254168.10.255.2554,094
177168.11.0.0/20168.11.0.1 to 168.11.15.254168.11.15.2554,094
178168.11.16.0/20168.11.16.1 to 168.11.31.254168.11.31.2554,094
179168.11.32.0/20168.11.32.1 to 168.11.47.254168.11.47.2554,094
180168.11.48.0/20168.11.48.1 to 168.11.63.254168.11.63.2554,094
181168.11.64.0/20168.11.64.1 to 168.11.79.254168.11.79.2554,094
182168.11.80.0/20168.11.80.1 to 168.11.95.254168.11.95.2554,094
183168.11.96.0/20168.11.96.1 to 168.11.111.254168.11.111.2554,094
184168.11.112.0/20168.11.112.1 to 168.11.127.254168.11.127.2554,094
185168.11.128.0/20168.11.128.1 to 168.11.143.254168.11.143.2554,094
186168.11.144.0/20168.11.144.1 to 168.11.159.254168.11.159.2554,094
187168.11.160.0/20168.11.160.1 to 168.11.175.254168.11.175.2554,094
188168.11.176.0/20168.11.176.1 to 168.11.191.254168.11.191.2554,094
189168.11.192.0/20168.11.192.1 to 168.11.207.254168.11.207.2554,094
190168.11.208.0/20168.11.208.1 to 168.11.223.254168.11.223.2554,094
191168.11.224.0/20168.11.224.1 to 168.11.239.254168.11.239.2554,094
192168.11.240.0/20168.11.240.1 to 168.11.255.254168.11.255.2554,094
193168.12.0.0/20168.12.0.1 to 168.12.15.254168.12.15.2554,094
194168.12.16.0/20168.12.16.1 to 168.12.31.254168.12.31.2554,094
195168.12.32.0/20168.12.32.1 to 168.12.47.254168.12.47.2554,094
196168.12.48.0/20168.12.48.1 to 168.12.63.254168.12.63.2554,094
197168.12.64.0/20168.12.64.1 to 168.12.79.254168.12.79.2554,094
198168.12.80.0/20168.12.80.1 to 168.12.95.254168.12.95.2554,094
199168.12.96.0/20168.12.96.1 to 168.12.111.254168.12.111.2554,094
200168.12.112.0/20168.12.112.1 to 168.12.127.254168.12.127.2554,094
201168.12.128.0/20168.12.128.1 to 168.12.143.254168.12.143.2554,094
202168.12.144.0/20168.12.144.1 to 168.12.159.254168.12.159.2554,094
203168.12.160.0/20168.12.160.1 to 168.12.175.254168.12.175.2554,094
204168.12.176.0/20168.12.176.1 to 168.12.191.254168.12.191.2554,094
205168.12.192.0/20168.12.192.1 to 168.12.207.254168.12.207.2554,094
206168.12.208.0/20168.12.208.1 to 168.12.223.254168.12.223.2554,094
207168.12.224.0/20168.12.224.1 to 168.12.239.254168.12.239.2554,094
208168.12.240.0/20168.12.240.1 to 168.12.255.254168.12.255.2554,094
209168.13.0.0/20168.13.0.1 to 168.13.15.254168.13.15.2554,094
210168.13.16.0/20168.13.16.1 to 168.13.31.254168.13.31.2554,094
211168.13.32.0/20168.13.32.1 to 168.13.47.254168.13.47.2554,094
212168.13.48.0/20168.13.48.1 to 168.13.63.254168.13.63.2554,094
213168.13.64.0/20168.13.64.1 to 168.13.79.254168.13.79.2554,094
214168.13.80.0/20168.13.80.1 to 168.13.95.254168.13.95.2554,094
215168.13.96.0/20168.13.96.1 to 168.13.111.254168.13.111.2554,094
216168.13.112.0/20168.13.112.1 to 168.13.127.254168.13.127.2554,094
217168.13.128.0/20168.13.128.1 to 168.13.143.254168.13.143.2554,094
218168.13.144.0/20168.13.144.1 to 168.13.159.254168.13.159.2554,094
219168.13.160.0/20168.13.160.1 to 168.13.175.254168.13.175.2554,094
220168.13.176.0/20168.13.176.1 to 168.13.191.254168.13.191.2554,094
221168.13.192.0/20168.13.192.1 to 168.13.207.254168.13.207.2554,094
222168.13.208.0/20168.13.208.1 to 168.13.223.254168.13.223.2554,094
223168.13.224.0/20168.13.224.1 to 168.13.239.254168.13.239.2554,094
224168.13.240.0/20168.13.240.1 to 168.13.255.254168.13.255.2554,094
225168.14.0.0/20168.14.0.1 to 168.14.15.254168.14.15.2554,094
226168.14.16.0/20168.14.16.1 to 168.14.31.254168.14.31.2554,094
227168.14.32.0/20168.14.32.1 to 168.14.47.254168.14.47.2554,094
228168.14.48.0/20168.14.48.1 to 168.14.63.254168.14.63.2554,094
229168.14.64.0/20168.14.64.1 to 168.14.79.254168.14.79.2554,094
230168.14.80.0/20168.14.80.1 to 168.14.95.254168.14.95.2554,094
231168.14.96.0/20168.14.96.1 to 168.14.111.254168.14.111.2554,094
232168.14.112.0/20168.14.112.1 to 168.14.127.254168.14.127.2554,094
233168.14.128.0/20168.14.128.1 to 168.14.143.254168.14.143.2554,094
234168.14.144.0/20168.14.144.1 to 168.14.159.254168.14.159.2554,094
235168.14.160.0/20168.14.160.1 to 168.14.175.254168.14.175.2554,094
236168.14.176.0/20168.14.176.1 to 168.14.191.254168.14.191.2554,094
237168.14.192.0/20168.14.192.1 to 168.14.207.254168.14.207.2554,094
238168.14.208.0/20168.14.208.1 to 168.14.223.254168.14.223.2554,094
239168.14.224.0/20168.14.224.1 to 168.14.239.254168.14.239.2554,094
240168.14.240.0/20168.14.240.1 to 168.14.255.254168.14.255.2554,094
241168.15.0.0/20168.15.0.1 to 168.15.15.254168.15.15.2554,094
242168.15.16.0/20168.15.16.1 to 168.15.31.254168.15.31.2554,094
243168.15.32.0/20168.15.32.1 to 168.15.47.254168.15.47.2554,094
244168.15.48.0/20168.15.48.1 to 168.15.63.254168.15.63.2554,094
245168.15.64.0/20168.15.64.1 to 168.15.79.254168.15.79.2554,094
246168.15.80.0/20168.15.80.1 to 168.15.95.254168.15.95.2554,094
247168.15.96.0/20168.15.96.1 to 168.15.111.254168.15.111.2554,094
248168.15.112.0/20168.15.112.1 to 168.15.127.254168.15.127.2554,094
249168.15.128.0/20168.15.128.1 to 168.15.143.254168.15.143.2554,094
250168.15.144.0/20168.15.144.1 to 168.15.159.254168.15.159.2554,094
251168.15.160.0/20168.15.160.1 to 168.15.175.254168.15.175.2554,094
252168.15.176.0/20168.15.176.1 to 168.15.191.254168.15.191.2554,094
253168.15.192.0/20168.15.192.1 to 168.15.207.254168.15.207.2554,094
254168.15.208.0/20168.15.208.1 to 168.15.223.254168.15.223.2554,094
255168.15.224.0/20168.15.224.1 to 168.15.239.254168.15.239.2554,094
256168.15.240.0/20168.15.240.1 to 168.15.255.254168.15.255.2554,094

IPv4 CIDR reference (/0 to /32)

IPv4 prefix lengths
PrefixSubnet maskWildcardAddressesUsable hostsSizeTypical use
/00.0.0.0255.255.255.2554,294,967,2964,294,967,29416,777,216 × /24
/1128.0.0.0127.255.255.2552,147,483,6482,147,483,6468,388,608 × /24
/2192.0.0.063.255.255.2551,073,741,8241,073,741,8224,194,304 × /24
/3224.0.0.031.255.255.255536,870,912536,870,9102,097,152 × /24
/4240.0.0.015.255.255.255268,435,456268,435,4541,048,576 × /24
/5248.0.0.07.255.255.255134,217,728134,217,726524,288 × /24
/6252.0.0.03.255.255.25567,108,86467,108,862262,144 × /24
/7254.0.0.01.255.255.25533,554,43233,554,430131,072 × /24
/8255.0.0.00.255.255.25516,777,21616,777,21465,536 × /24Old class A; 10.0.0.0/8
/9255.128.0.00.127.255.2558,388,6088,388,60632,768 × /24
/10255.192.0.00.63.255.2554,194,3044,194,30216,384 × /24
/11255.224.0.00.31.255.2552,097,1522,097,1508,192 × /24
/12255.240.0.00.15.255.2551,048,5761,048,5744,096 × /24172.16.0.0/12
/13255.248.0.00.7.255.255524,288524,2862,048 × /24
/14255.252.0.00.3.255.255262,144262,1421,024 × /24
/15255.254.0.00.1.255.255131,072131,070512 × /24
/16255.255.0.00.0.255.25565,53665,534256 × /24Old class B; 192.168.0.0/16
/17255.255.128.00.0.127.25532,76832,766128 × /24
/18255.255.192.00.0.63.25516,38416,38264 × /24
/19255.255.224.00.0.31.2558,1928,19032 × /24
/20255.255.240.00.0.15.2554,0964,09416 × /24
/21255.255.248.00.0.7.2552,0482,0468 × /24
/22255.255.252.00.0.3.2551,0241,0224 × /24Large office or guest Wi-Fi (1,022 hosts)
/23255.255.254.00.0.1.2555125102 × /24Larger office LAN (510 hosts)
/24255.255.255.00.0.0.2552562541 × /24Typical office LAN (old class C)
/25255.255.255.1280.0.0.1271281261/2 of a /24Smaller LAN or VLAN
/26255.255.255.1920.0.0.6364621/4 of a /24Smaller LAN or VLAN
/27255.255.255.2240.0.0.3132301/8 of a /24Small VLAN, phones, cameras
/28255.255.255.2400.0.0.1516141/16 of a /24Small VLAN, phones, cameras
/29255.255.255.2480.0.0.7861/32 of a /24Small fixed public block (5 usable)
/30255.255.255.2520.0.0.3421/64 of a /24Point-to-point (old style)
/31255.255.255.2540.0.0.1221/128 of a /24Point-to-point link (RFC 3021)
/32255.255.255.2550.0.0.0111/256 of a /24One host

IPv6 prefix reference

IPv6 prefix lengths
PrefixAddresses/64 LANs/48 sitesNibbleTypical use
/342,535,295,865,117,307,932,921,825,928,971,026,432 (2^125)2,305,843,009,213,693,95235,184,372,088,832NoAll global unicast (2000::/3)
/165,192,296,858,534,827,628,530,496,329,220,096 (2^112)281,474,976,710,6564,294,967,296Yes
/20324,518,553,658,426,726,783,156,020,576,256 (2^108)17,592,186,044,416268,435,456YesLarge provider allocation (RIPE minimum for some)
/29633,825,300,114,114,700,748,351,602,688 (2^99)34,359,738,368524,288NoRIPE allocation to a provider (often)
/3279,228,162,514,264,337,593,543,950,336 (2^96)4,294,967,29665,536YesProvider allocation (RIPE default)
/364,951,760,157,141,521,099,596,496,896 (2^92)268,435,4564,096Yes
/40309,485,009,821,345,068,724,781,056 (2^88)16,777,216256Yes
/4419,342,813,113,834,066,795,298,816 (2^84)1,048,57616Yes
/481,208,925,819,614,629,174,706,176 (2^80)65,5361YesOne site or organisation (RIPE PI / assignment)
/5275,557,863,725,914,323,419,136 (2^76)4,096Yes
/564,722,366,482,869,645,213,696 (2^72)256YesSmall site or home (common provider assignment)
/60295,147,905,179,352,825,856 (2^68)16YesSome home broadband (16 LANs)
/6418,446,744,073,709,551,616 (2^64)1YesOne LAN or VLAN (needed for SLAAC)
/7272,057,594,037,927,936 (2^56)1/256 of a /64Yes
/80281,474,976,710,656 (2^48)1/65,536 of a /64Yes
/964,294,967,2961/4,294,967,296 of a /64YesEmbeds an IPv4 address (NAT64)
/11265,5361/281,474,976,710,656 of a /64Yes
/1202561/72,057,594,037,927,936 of a /64Yes
/124161/1,152,921,504,606,846,976 of a /64Yes
/12641/4,611,686,018,427,387,904 of a /64No
/12721/9,223,372,036,854,775,808 of a /64NoPoint-to-point link (RFC 6164)
/12811/18,446,744,073,709,551,616 of a /64YesOne host or loopback

Private and special ranges

IPv4

Special-purpose ranges
RangeNameWhat it is
255.255.255.255/32Limited broadcastEvery host on the local network
0.0.0.0/8This networkNot routed; 0.0.0.0 means "any address" in settings
10.0.0.0/8Private (RFC 1918)Office and home networks; not routed on the internet
100.64.0.0/10Shared address space (CGNAT)Used by providers behind carrier-grade NAT (RFC 6598)
127.0.0.0/8LoopbackThis computer
169.254.0.0/16Link-local (APIPA)Self-assigned when no DHCP server answers
172.16.0.0/12Private (RFC 1918)Office and home networks; not routed on the internet
192.0.0.0/24IETF protocol assignmentsSpecial uses such as DS-Lite
192.0.2.0/24Documentation (TEST-NET-1)For examples; never used on a network
192.88.99.0/246to4 relay (deprecated)Formerly anycast for 6to4
192.168.0.0/16Private (RFC 1918)Office and home networks; not routed on the internet
198.18.0.0/15BenchmarkingNetwork equipment testing (RFC 2544)
198.51.100.0/24Documentation (TEST-NET-2)For examples; never used on a network
203.0.113.0/24Documentation (TEST-NET-3)For examples; never used on a network
224.0.0.0/4MulticastOne-to-many traffic, such as IPTV and routing protocols
240.0.0.0/4ReservedFuture use; not usable on most systems

IPv6

Special-purpose ranges
RangeNameWhat it is
::/128UnspecifiedNo address; :: means "any address" in settings
::1/128LoopbackThis computer
::ffff:0:0/96IPv4-mappedAn IPv4 address written as IPv6
64:ff9b::/96NAT64IPv4 addresses reached through a NAT64 gateway
100::/64Discard onlyTraffic sent here is dropped (RFC 6666)
2001:db8::/32DocumentationFor examples; never used on a network
2001::/32TeredoIPv6 tunnelled over IPv4 UDP
2002::/166to4IPv6 tunnelled over IPv4 (largely retired)
3fff::/20DocumentationFor examples (RFC 9637)
fc00::/7Unique local (ULA)Private IPv6, like RFC 1918; usually fd00::/8
fe80::/10Link-localEvery IPv6 interface has one; not routed
ff00::/8MulticastOne-to-many traffic; replaces broadcast
2000::/3Global unicastPublic internet addresses

About this tool

A network is written as an address and a prefix length, such as 192.168.1.0/24: the first 24 bits name the network and the rest number the devices on it. The calculator works out where the network starts and ends, how many devices it holds, its subnet and wildcard masks, and the reverse DNS zone to ask your provider for.

It also splits a network into equal smaller ones (one per VLAN or site), turns a range of addresses into the fewest CIDR blocks for a firewall rule, and lists every IPv4 prefix length and the common IPv6 ones in reference tables.

Common questions

Why are two addresses lost in every IPv4 subnet?

The first address names the network and the last is the broadcast address, so a /24 has 256 addresses but 254 for devices. A /31 (a link between two routers) and a /32 (one host) are the exceptions.

What size of IPv6 network should a LAN use?

Always /64. Devices pick their own address within it (SLAAC), which needs the full 64 bits. A site usually gets a /48 or /56 from its provider, which holds 65,536 or 256 LANs.

What is a wildcard mask?

The subnet mask turned inside out: 255.255.255.0 becomes 0.0.0.255. Cisco access lists and OSPF use it to say which bits must match.

Which ranges can I use inside an office?

IPv4: 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16. IPv6: unique local addresses from fd00::/8, though most networks use the public prefix from their provider.