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Speed and call quality testTest delay, jitter and speed, with a focus on phone calls.My IP addressYour public IPv4 and IPv6 addresses, provider and address range.WhoIs lookupWho owns a domain or IP address, when it expires, and its DNS.DNS reportEvery DNS record for a domain, with email setup checked.IP subnet calculatorWork out a network's range, mask and hosts, and split it into subnets.

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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.

Prefix/16
Addresses2^112
/64 networks2^48
Network
ffb6::/16
First address
ffb6::
Last address
ffb6:ffff:ffff:ffff:ffff:ffff:ffff:ffff
Addresses
5,192,296,858,534,827,628,530,496,329,220,096 (2^112)
/64 networks (LANs)
281,474,976,710,656 (2^48)
Full form
ffb6:0000:0000:0000:0000:0000:0000:0000
Type
Multicast ff00::/8
One-to-many traffic; replaces broadcast
Reverse DNS zone
6.b.f.f.ip6.arpa
Split into smaller subnets/32
/17 (2)/18 (4)/19 (8)/20 (16)/24 (256)/28 (4,096)/32 (65,536)

ffb6::/16 makes 65,536 subnets of /32; the first 256 are listed.

Subnets
#SubnetLast address
1ffb6::/32ffb6:0:ffff:ffff:ffff:ffff:ffff:ffff
2ffb6:1::/32ffb6:1:ffff:ffff:ffff:ffff:ffff:ffff
3ffb6:2::/32ffb6:2:ffff:ffff:ffff:ffff:ffff:ffff
4ffb6:3::/32ffb6:3:ffff:ffff:ffff:ffff:ffff:ffff
5ffb6:4::/32ffb6:4:ffff:ffff:ffff:ffff:ffff:ffff
6ffb6:5::/32ffb6:5:ffff:ffff:ffff:ffff:ffff:ffff
7ffb6:6::/32ffb6:6:ffff:ffff:ffff:ffff:ffff:ffff
8ffb6:7::/32ffb6:7:ffff:ffff:ffff:ffff:ffff:ffff
9ffb6:8::/32ffb6:8:ffff:ffff:ffff:ffff:ffff:ffff
10ffb6:9::/32ffb6:9:ffff:ffff:ffff:ffff:ffff:ffff
11ffb6:a::/32ffb6:a:ffff:ffff:ffff:ffff:ffff:ffff
12ffb6:b::/32ffb6:b:ffff:ffff:ffff:ffff:ffff:ffff
13ffb6:c::/32ffb6:c:ffff:ffff:ffff:ffff:ffff:ffff
14ffb6:d::/32ffb6:d:ffff:ffff:ffff:ffff:ffff:ffff
15ffb6:e::/32ffb6:e:ffff:ffff:ffff:ffff:ffff:ffff
16ffb6:f::/32ffb6:f:ffff:ffff:ffff:ffff:ffff:ffff
17ffb6:10::/32ffb6:10:ffff:ffff:ffff:ffff:ffff:ffff
18ffb6:11::/32ffb6:11:ffff:ffff:ffff:ffff:ffff:ffff
19ffb6:12::/32ffb6:12:ffff:ffff:ffff:ffff:ffff:ffff
20ffb6:13::/32ffb6:13:ffff:ffff:ffff:ffff:ffff:ffff
21ffb6:14::/32ffb6:14:ffff:ffff:ffff:ffff:ffff:ffff
22ffb6:15::/32ffb6:15:ffff:ffff:ffff:ffff:ffff:ffff
23ffb6:16::/32ffb6:16:ffff:ffff:ffff:ffff:ffff:ffff
24ffb6:17::/32ffb6:17:ffff:ffff:ffff:ffff:ffff:ffff
25ffb6:18::/32ffb6:18:ffff:ffff:ffff:ffff:ffff:ffff
26ffb6:19::/32ffb6:19:ffff:ffff:ffff:ffff:ffff:ffff
27ffb6:1a::/32ffb6:1a:ffff:ffff:ffff:ffff:ffff:ffff
28ffb6:1b::/32ffb6:1b:ffff:ffff:ffff:ffff:ffff:ffff
29ffb6:1c::/32ffb6:1c:ffff:ffff:ffff:ffff:ffff:ffff
30ffb6:1d::/32ffb6:1d:ffff:ffff:ffff:ffff:ffff:ffff
31ffb6:1e::/32ffb6:1e:ffff:ffff:ffff:ffff:ffff:ffff
32ffb6:1f::/32ffb6:1f:ffff:ffff:ffff:ffff:ffff:ffff
33ffb6:20::/32ffb6:20:ffff:ffff:ffff:ffff:ffff:ffff
34ffb6:21::/32ffb6:21:ffff:ffff:ffff:ffff:ffff:ffff
35ffb6:22::/32ffb6:22:ffff:ffff:ffff:ffff:ffff:ffff
36ffb6:23::/32ffb6:23:ffff:ffff:ffff:ffff:ffff:ffff
37ffb6:24::/32ffb6:24:ffff:ffff:ffff:ffff:ffff:ffff
38ffb6:25::/32ffb6:25:ffff:ffff:ffff:ffff:ffff:ffff
39ffb6:26::/32ffb6:26:ffff:ffff:ffff:ffff:ffff:ffff
40ffb6:27::/32ffb6:27:ffff:ffff:ffff:ffff:ffff:ffff
41ffb6:28::/32ffb6:28:ffff:ffff:ffff:ffff:ffff:ffff
42ffb6:29::/32ffb6:29:ffff:ffff:ffff:ffff:ffff:ffff
43ffb6:2a::/32ffb6:2a:ffff:ffff:ffff:ffff:ffff:ffff
44ffb6:2b::/32ffb6:2b:ffff:ffff:ffff:ffff:ffff:ffff
45ffb6:2c::/32ffb6:2c:ffff:ffff:ffff:ffff:ffff:ffff
46ffb6:2d::/32ffb6:2d:ffff:ffff:ffff:ffff:ffff:ffff
47ffb6:2e::/32ffb6:2e:ffff:ffff:ffff:ffff:ffff:ffff
48ffb6:2f::/32ffb6:2f:ffff:ffff:ffff:ffff:ffff:ffff
49ffb6:30::/32ffb6:30:ffff:ffff:ffff:ffff:ffff:ffff
50ffb6:31::/32ffb6:31:ffff:ffff:ffff:ffff:ffff:ffff
51ffb6:32::/32ffb6:32:ffff:ffff:ffff:ffff:ffff:ffff
52ffb6:33::/32ffb6:33:ffff:ffff:ffff:ffff:ffff:ffff
53ffb6:34::/32ffb6:34:ffff:ffff:ffff:ffff:ffff:ffff
54ffb6:35::/32ffb6:35:ffff:ffff:ffff:ffff:ffff:ffff
55ffb6:36::/32ffb6:36:ffff:ffff:ffff:ffff:ffff:ffff
56ffb6:37::/32ffb6:37:ffff:ffff:ffff:ffff:ffff:ffff
57ffb6:38::/32ffb6:38:ffff:ffff:ffff:ffff:ffff:ffff
58ffb6:39::/32ffb6:39:ffff:ffff:ffff:ffff:ffff:ffff
59ffb6:3a::/32ffb6:3a:ffff:ffff:ffff:ffff:ffff:ffff
60ffb6:3b::/32ffb6:3b:ffff:ffff:ffff:ffff:ffff:ffff
61ffb6:3c::/32ffb6:3c:ffff:ffff:ffff:ffff:ffff:ffff
62ffb6:3d::/32ffb6:3d:ffff:ffff:ffff:ffff:ffff:ffff
63ffb6:3e::/32ffb6:3e:ffff:ffff:ffff:ffff:ffff:ffff
64ffb6:3f::/32ffb6:3f:ffff:ffff:ffff:ffff:ffff:ffff
65ffb6:40::/32ffb6:40:ffff:ffff:ffff:ffff:ffff:ffff
66ffb6:41::/32ffb6:41:ffff:ffff:ffff:ffff:ffff:ffff
67ffb6:42::/32ffb6:42:ffff:ffff:ffff:ffff:ffff:ffff
68ffb6:43::/32ffb6:43:ffff:ffff:ffff:ffff:ffff:ffff
69ffb6:44::/32ffb6:44:ffff:ffff:ffff:ffff:ffff:ffff
70ffb6:45::/32ffb6:45:ffff:ffff:ffff:ffff:ffff:ffff
71ffb6:46::/32ffb6:46:ffff:ffff:ffff:ffff:ffff:ffff
72ffb6:47::/32ffb6:47:ffff:ffff:ffff:ffff:ffff:ffff
73ffb6:48::/32ffb6:48:ffff:ffff:ffff:ffff:ffff:ffff
74ffb6:49::/32ffb6:49:ffff:ffff:ffff:ffff:ffff:ffff
75ffb6:4a::/32ffb6:4a:ffff:ffff:ffff:ffff:ffff:ffff
76ffb6:4b::/32ffb6:4b:ffff:ffff:ffff:ffff:ffff:ffff
77ffb6:4c::/32ffb6:4c:ffff:ffff:ffff:ffff:ffff:ffff
78ffb6:4d::/32ffb6:4d:ffff:ffff:ffff:ffff:ffff:ffff
79ffb6:4e::/32ffb6:4e:ffff:ffff:ffff:ffff:ffff:ffff
80ffb6:4f::/32ffb6:4f:ffff:ffff:ffff:ffff:ffff:ffff
81ffb6:50::/32ffb6:50:ffff:ffff:ffff:ffff:ffff:ffff
82ffb6:51::/32ffb6:51:ffff:ffff:ffff:ffff:ffff:ffff
83ffb6:52::/32ffb6:52:ffff:ffff:ffff:ffff:ffff:ffff
84ffb6:53::/32ffb6:53:ffff:ffff:ffff:ffff:ffff:ffff
85ffb6:54::/32ffb6:54:ffff:ffff:ffff:ffff:ffff:ffff
86ffb6:55::/32ffb6:55:ffff:ffff:ffff:ffff:ffff:ffff
87ffb6:56::/32ffb6:56:ffff:ffff:ffff:ffff:ffff:ffff
88ffb6:57::/32ffb6:57:ffff:ffff:ffff:ffff:ffff:ffff
89ffb6:58::/32ffb6:58:ffff:ffff:ffff:ffff:ffff:ffff
90ffb6:59::/32ffb6:59:ffff:ffff:ffff:ffff:ffff:ffff
91ffb6:5a::/32ffb6:5a:ffff:ffff:ffff:ffff:ffff:ffff
92ffb6:5b::/32ffb6:5b:ffff:ffff:ffff:ffff:ffff:ffff
93ffb6:5c::/32ffb6:5c:ffff:ffff:ffff:ffff:ffff:ffff
94ffb6:5d::/32ffb6:5d:ffff:ffff:ffff:ffff:ffff:ffff
95ffb6:5e::/32ffb6:5e:ffff:ffff:ffff:ffff:ffff:ffff
96ffb6:5f::/32ffb6:5f:ffff:ffff:ffff:ffff:ffff:ffff
97ffb6:60::/32ffb6:60:ffff:ffff:ffff:ffff:ffff:ffff
98ffb6:61::/32ffb6:61:ffff:ffff:ffff:ffff:ffff:ffff
99ffb6:62::/32ffb6:62:ffff:ffff:ffff:ffff:ffff:ffff
100ffb6:63::/32ffb6:63:ffff:ffff:ffff:ffff:ffff:ffff
101ffb6:64::/32ffb6:64:ffff:ffff:ffff:ffff:ffff:ffff
102ffb6:65::/32ffb6:65:ffff:ffff:ffff:ffff:ffff:ffff
103ffb6:66::/32ffb6:66:ffff:ffff:ffff:ffff:ffff:ffff
104ffb6:67::/32ffb6:67:ffff:ffff:ffff:ffff:ffff:ffff
105ffb6:68::/32ffb6:68:ffff:ffff:ffff:ffff:ffff:ffff
106ffb6:69::/32ffb6:69:ffff:ffff:ffff:ffff:ffff:ffff
107ffb6:6a::/32ffb6:6a:ffff:ffff:ffff:ffff:ffff:ffff
108ffb6:6b::/32ffb6:6b:ffff:ffff:ffff:ffff:ffff:ffff
109ffb6:6c::/32ffb6:6c:ffff:ffff:ffff:ffff:ffff:ffff
110ffb6:6d::/32ffb6:6d:ffff:ffff:ffff:ffff:ffff:ffff
111ffb6:6e::/32ffb6:6e:ffff:ffff:ffff:ffff:ffff:ffff
112ffb6:6f::/32ffb6:6f:ffff:ffff:ffff:ffff:ffff:ffff
113ffb6:70::/32ffb6:70:ffff:ffff:ffff:ffff:ffff:ffff
114ffb6:71::/32ffb6:71:ffff:ffff:ffff:ffff:ffff:ffff
115ffb6:72::/32ffb6:72:ffff:ffff:ffff:ffff:ffff:ffff
116ffb6:73::/32ffb6:73:ffff:ffff:ffff:ffff:ffff:ffff
117ffb6:74::/32ffb6:74:ffff:ffff:ffff:ffff:ffff:ffff
118ffb6:75::/32ffb6:75:ffff:ffff:ffff:ffff:ffff:ffff
119ffb6:76::/32ffb6:76:ffff:ffff:ffff:ffff:ffff:ffff
120ffb6:77::/32ffb6:77:ffff:ffff:ffff:ffff:ffff:ffff
121ffb6:78::/32ffb6:78:ffff:ffff:ffff:ffff:ffff:ffff
122ffb6:79::/32ffb6:79:ffff:ffff:ffff:ffff:ffff:ffff
123ffb6:7a::/32ffb6:7a:ffff:ffff:ffff:ffff:ffff:ffff
124ffb6:7b::/32ffb6:7b:ffff:ffff:ffff:ffff:ffff:ffff
125ffb6:7c::/32ffb6:7c:ffff:ffff:ffff:ffff:ffff:ffff
126ffb6:7d::/32ffb6:7d:ffff:ffff:ffff:ffff:ffff:ffff
127ffb6:7e::/32ffb6:7e:ffff:ffff:ffff:ffff:ffff:ffff
128ffb6:7f::/32ffb6:7f:ffff:ffff:ffff:ffff:ffff:ffff
129ffb6:80::/32ffb6:80:ffff:ffff:ffff:ffff:ffff:ffff
130ffb6:81::/32ffb6:81:ffff:ffff:ffff:ffff:ffff:ffff
131ffb6:82::/32ffb6:82:ffff:ffff:ffff:ffff:ffff:ffff
132ffb6:83::/32ffb6:83:ffff:ffff:ffff:ffff:ffff:ffff
133ffb6:84::/32ffb6:84:ffff:ffff:ffff:ffff:ffff:ffff
134ffb6:85::/32ffb6:85:ffff:ffff:ffff:ffff:ffff:ffff
135ffb6:86::/32ffb6:86:ffff:ffff:ffff:ffff:ffff:ffff
136ffb6:87::/32ffb6:87:ffff:ffff:ffff:ffff:ffff:ffff
137ffb6:88::/32ffb6:88:ffff:ffff:ffff:ffff:ffff:ffff
138ffb6:89::/32ffb6:89:ffff:ffff:ffff:ffff:ffff:ffff
139ffb6:8a::/32ffb6:8a:ffff:ffff:ffff:ffff:ffff:ffff
140ffb6:8b::/32ffb6:8b:ffff:ffff:ffff:ffff:ffff:ffff
141ffb6:8c::/32ffb6:8c:ffff:ffff:ffff:ffff:ffff:ffff
142ffb6:8d::/32ffb6:8d:ffff:ffff:ffff:ffff:ffff:ffff
143ffb6:8e::/32ffb6:8e:ffff:ffff:ffff:ffff:ffff:ffff
144ffb6:8f::/32ffb6:8f:ffff:ffff:ffff:ffff:ffff:ffff
145ffb6:90::/32ffb6:90:ffff:ffff:ffff:ffff:ffff:ffff
146ffb6:91::/32ffb6:91:ffff:ffff:ffff:ffff:ffff:ffff
147ffb6:92::/32ffb6:92:ffff:ffff:ffff:ffff:ffff:ffff
148ffb6:93::/32ffb6:93:ffff:ffff:ffff:ffff:ffff:ffff
149ffb6:94::/32ffb6:94:ffff:ffff:ffff:ffff:ffff:ffff
150ffb6:95::/32ffb6:95:ffff:ffff:ffff:ffff:ffff:ffff
151ffb6:96::/32ffb6:96:ffff:ffff:ffff:ffff:ffff:ffff
152ffb6:97::/32ffb6:97:ffff:ffff:ffff:ffff:ffff:ffff
153ffb6:98::/32ffb6:98:ffff:ffff:ffff:ffff:ffff:ffff
154ffb6:99::/32ffb6:99:ffff:ffff:ffff:ffff:ffff:ffff
155ffb6:9a::/32ffb6:9a:ffff:ffff:ffff:ffff:ffff:ffff
156ffb6:9b::/32ffb6:9b:ffff:ffff:ffff:ffff:ffff:ffff
157ffb6:9c::/32ffb6:9c:ffff:ffff:ffff:ffff:ffff:ffff
158ffb6:9d::/32ffb6:9d:ffff:ffff:ffff:ffff:ffff:ffff
159ffb6:9e::/32ffb6:9e:ffff:ffff:ffff:ffff:ffff:ffff
160ffb6:9f::/32ffb6:9f:ffff:ffff:ffff:ffff:ffff:ffff
161ffb6:a0::/32ffb6:a0:ffff:ffff:ffff:ffff:ffff:ffff
162ffb6:a1::/32ffb6:a1:ffff:ffff:ffff:ffff:ffff:ffff
163ffb6:a2::/32ffb6:a2:ffff:ffff:ffff:ffff:ffff:ffff
164ffb6:a3::/32ffb6:a3:ffff:ffff:ffff:ffff:ffff:ffff
165ffb6:a4::/32ffb6:a4:ffff:ffff:ffff:ffff:ffff:ffff
166ffb6:a5::/32ffb6:a5:ffff:ffff:ffff:ffff:ffff:ffff
167ffb6:a6::/32ffb6:a6:ffff:ffff:ffff:ffff:ffff:ffff
168ffb6:a7::/32ffb6:a7:ffff:ffff:ffff:ffff:ffff:ffff
169ffb6:a8::/32ffb6:a8:ffff:ffff:ffff:ffff:ffff:ffff
170ffb6:a9::/32ffb6:a9:ffff:ffff:ffff:ffff:ffff:ffff
171ffb6:aa::/32ffb6:aa:ffff:ffff:ffff:ffff:ffff:ffff
172ffb6:ab::/32ffb6:ab:ffff:ffff:ffff:ffff:ffff:ffff
173ffb6:ac::/32ffb6:ac:ffff:ffff:ffff:ffff:ffff:ffff
174ffb6:ad::/32ffb6:ad:ffff:ffff:ffff:ffff:ffff:ffff
175ffb6:ae::/32ffb6:ae:ffff:ffff:ffff:ffff:ffff:ffff
176ffb6:af::/32ffb6:af:ffff:ffff:ffff:ffff:ffff:ffff
177ffb6:b0::/32ffb6:b0:ffff:ffff:ffff:ffff:ffff:ffff
178ffb6:b1::/32ffb6:b1:ffff:ffff:ffff:ffff:ffff:ffff
179ffb6:b2::/32ffb6:b2:ffff:ffff:ffff:ffff:ffff:ffff
180ffb6:b3::/32ffb6:b3:ffff:ffff:ffff:ffff:ffff:ffff
181ffb6:b4::/32ffb6:b4:ffff:ffff:ffff:ffff:ffff:ffff
182ffb6:b5::/32ffb6:b5:ffff:ffff:ffff:ffff:ffff:ffff
183ffb6:b6::/32ffb6:b6:ffff:ffff:ffff:ffff:ffff:ffff
184ffb6:b7::/32ffb6:b7:ffff:ffff:ffff:ffff:ffff:ffff
185ffb6:b8::/32ffb6:b8:ffff:ffff:ffff:ffff:ffff:ffff
186ffb6:b9::/32ffb6:b9:ffff:ffff:ffff:ffff:ffff:ffff
187ffb6:ba::/32ffb6:ba:ffff:ffff:ffff:ffff:ffff:ffff
188ffb6:bb::/32ffb6:bb:ffff:ffff:ffff:ffff:ffff:ffff
189ffb6:bc::/32ffb6:bc:ffff:ffff:ffff:ffff:ffff:ffff
190ffb6:bd::/32ffb6:bd:ffff:ffff:ffff:ffff:ffff:ffff
191ffb6:be::/32ffb6:be:ffff:ffff:ffff:ffff:ffff:ffff
192ffb6:bf::/32ffb6:bf:ffff:ffff:ffff:ffff:ffff:ffff
193ffb6:c0::/32ffb6:c0:ffff:ffff:ffff:ffff:ffff:ffff
194ffb6:c1::/32ffb6:c1:ffff:ffff:ffff:ffff:ffff:ffff
195ffb6:c2::/32ffb6:c2:ffff:ffff:ffff:ffff:ffff:ffff
196ffb6:c3::/32ffb6:c3:ffff:ffff:ffff:ffff:ffff:ffff
197ffb6:c4::/32ffb6:c4:ffff:ffff:ffff:ffff:ffff:ffff
198ffb6:c5::/32ffb6:c5:ffff:ffff:ffff:ffff:ffff:ffff
199ffb6:c6::/32ffb6:c6:ffff:ffff:ffff:ffff:ffff:ffff
200ffb6:c7::/32ffb6:c7:ffff:ffff:ffff:ffff:ffff:ffff
201ffb6:c8::/32ffb6:c8:ffff:ffff:ffff:ffff:ffff:ffff
202ffb6:c9::/32ffb6:c9:ffff:ffff:ffff:ffff:ffff:ffff
203ffb6:ca::/32ffb6:ca:ffff:ffff:ffff:ffff:ffff:ffff
204ffb6:cb::/32ffb6:cb:ffff:ffff:ffff:ffff:ffff:ffff
205ffb6:cc::/32ffb6:cc:ffff:ffff:ffff:ffff:ffff:ffff
206ffb6:cd::/32ffb6:cd:ffff:ffff:ffff:ffff:ffff:ffff
207ffb6:ce::/32ffb6:ce:ffff:ffff:ffff:ffff:ffff:ffff
208ffb6:cf::/32ffb6:cf:ffff:ffff:ffff:ffff:ffff:ffff
209ffb6:d0::/32ffb6:d0:ffff:ffff:ffff:ffff:ffff:ffff
210ffb6:d1::/32ffb6:d1:ffff:ffff:ffff:ffff:ffff:ffff
211ffb6:d2::/32ffb6:d2:ffff:ffff:ffff:ffff:ffff:ffff
212ffb6:d3::/32ffb6:d3:ffff:ffff:ffff:ffff:ffff:ffff
213ffb6:d4::/32ffb6:d4:ffff:ffff:ffff:ffff:ffff:ffff
214ffb6:d5::/32ffb6:d5:ffff:ffff:ffff:ffff:ffff:ffff
215ffb6:d6::/32ffb6:d6:ffff:ffff:ffff:ffff:ffff:ffff
216ffb6:d7::/32ffb6:d7:ffff:ffff:ffff:ffff:ffff:ffff
217ffb6:d8::/32ffb6:d8:ffff:ffff:ffff:ffff:ffff:ffff
218ffb6:d9::/32ffb6:d9:ffff:ffff:ffff:ffff:ffff:ffff
219ffb6:da::/32ffb6:da:ffff:ffff:ffff:ffff:ffff:ffff
220ffb6:db::/32ffb6:db:ffff:ffff:ffff:ffff:ffff:ffff
221ffb6:dc::/32ffb6:dc:ffff:ffff:ffff:ffff:ffff:ffff
222ffb6:dd::/32ffb6:dd:ffff:ffff:ffff:ffff:ffff:ffff
223ffb6:de::/32ffb6:de:ffff:ffff:ffff:ffff:ffff:ffff
224ffb6:df::/32ffb6:df:ffff:ffff:ffff:ffff:ffff:ffff
225ffb6:e0::/32ffb6:e0:ffff:ffff:ffff:ffff:ffff:ffff
226ffb6:e1::/32ffb6:e1:ffff:ffff:ffff:ffff:ffff:ffff
227ffb6:e2::/32ffb6:e2:ffff:ffff:ffff:ffff:ffff:ffff
228ffb6:e3::/32ffb6:e3:ffff:ffff:ffff:ffff:ffff:ffff
229ffb6:e4::/32ffb6:e4:ffff:ffff:ffff:ffff:ffff:ffff
230ffb6:e5::/32ffb6:e5:ffff:ffff:ffff:ffff:ffff:ffff
231ffb6:e6::/32ffb6:e6:ffff:ffff:ffff:ffff:ffff:ffff
232ffb6:e7::/32ffb6:e7:ffff:ffff:ffff:ffff:ffff:ffff
233ffb6:e8::/32ffb6:e8:ffff:ffff:ffff:ffff:ffff:ffff
234ffb6:e9::/32ffb6:e9:ffff:ffff:ffff:ffff:ffff:ffff
235ffb6:ea::/32ffb6:ea:ffff:ffff:ffff:ffff:ffff:ffff
236ffb6:eb::/32ffb6:eb:ffff:ffff:ffff:ffff:ffff:ffff
237ffb6:ec::/32ffb6:ec:ffff:ffff:ffff:ffff:ffff:ffff
238ffb6:ed::/32ffb6:ed:ffff:ffff:ffff:ffff:ffff:ffff
239ffb6:ee::/32ffb6:ee:ffff:ffff:ffff:ffff:ffff:ffff
240ffb6:ef::/32ffb6:ef:ffff:ffff:ffff:ffff:ffff:ffff
241ffb6:f0::/32ffb6:f0:ffff:ffff:ffff:ffff:ffff:ffff
242ffb6:f1::/32ffb6:f1:ffff:ffff:ffff:ffff:ffff:ffff
243ffb6:f2::/32ffb6:f2:ffff:ffff:ffff:ffff:ffff:ffff
244ffb6:f3::/32ffb6:f3:ffff:ffff:ffff:ffff:ffff:ffff
245ffb6:f4::/32ffb6:f4:ffff:ffff:ffff:ffff:ffff:ffff
246ffb6:f5::/32ffb6:f5:ffff:ffff:ffff:ffff:ffff:ffff
247ffb6:f6::/32ffb6:f6:ffff:ffff:ffff:ffff:ffff:ffff
248ffb6:f7::/32ffb6:f7:ffff:ffff:ffff:ffff:ffff:ffff
249ffb6:f8::/32ffb6:f8:ffff:ffff:ffff:ffff:ffff:ffff
250ffb6:f9::/32ffb6:f9:ffff:ffff:ffff:ffff:ffff:ffff
251ffb6:fa::/32ffb6:fa:ffff:ffff:ffff:ffff:ffff:ffff
252ffb6:fb::/32ffb6:fb:ffff:ffff:ffff:ffff:ffff:ffff
253ffb6:fc::/32ffb6:fc:ffff:ffff:ffff:ffff:ffff:ffff
254ffb6:fd::/32ffb6:fd:ffff:ffff:ffff:ffff:ffff:ffff
255ffb6:fe::/32ffb6:fe:ffff:ffff:ffff:ffff:ffff:ffff
256ffb6:ff::/32ffb6:ff:ffff:ffff:ffff:ffff:ffff:ffff

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.