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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
ffcd::/16
First address
ffcd::
Last address
ffcd: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
ffcd:0000:0000:0000:0000:0000:0000:0000
Type
Multicast ff00::/8
One-to-many traffic; replaces broadcast
Reverse DNS zone
d.c.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)

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

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