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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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Update checkIs this computer, phone and browser up to date? With links to update.Camera and mic testCheck your webcam and microphone before a call.Test print pagePrint an A4 page to check a printer: edges, text, line art and colours.

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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/20
Addresses2^108
/64 networks2^44
Network
ff0d:5000::/20
First address
ff0d:5000::
Last address
ff0d:5fff:ffff:ffff:ffff:ffff:ffff:ffff
Addresses
324,518,553,658,426,726,783,156,020,576,256 (2^108)
/64 networks (LANs)
17,592,186,044,416 (2^44)
Full form
ff0d:5000:0000:0000:0000:0000:0000:0000
Type
Multicast ff00::/8
One-to-many traffic; replaces broadcast
Reverse DNS zone
5.d.0.f.f.ip6.arpa
Split into smaller subnets/28
/21 (2)/22 (4)/23 (8)/24 (16)/28 (256)/32 (4,096)/36 (65,536)

ff0d:5000::/20 makes 256 subnets of /28.

Subnets
#SubnetLast address
1ff0d:5000::/28ff0d:500f:ffff:ffff:ffff:ffff:ffff:ffff
2ff0d:5010::/28ff0d:501f:ffff:ffff:ffff:ffff:ffff:ffff
3ff0d:5020::/28ff0d:502f:ffff:ffff:ffff:ffff:ffff:ffff
4ff0d:5030::/28ff0d:503f:ffff:ffff:ffff:ffff:ffff:ffff
5ff0d:5040::/28ff0d:504f:ffff:ffff:ffff:ffff:ffff:ffff
6ff0d:5050::/28ff0d:505f:ffff:ffff:ffff:ffff:ffff:ffff
7ff0d:5060::/28ff0d:506f:ffff:ffff:ffff:ffff:ffff:ffff
8ff0d:5070::/28ff0d:507f:ffff:ffff:ffff:ffff:ffff:ffff
9ff0d:5080::/28ff0d:508f:ffff:ffff:ffff:ffff:ffff:ffff
10ff0d:5090::/28ff0d:509f:ffff:ffff:ffff:ffff:ffff:ffff
11ff0d:50a0::/28ff0d:50af:ffff:ffff:ffff:ffff:ffff:ffff
12ff0d:50b0::/28ff0d:50bf:ffff:ffff:ffff:ffff:ffff:ffff
13ff0d:50c0::/28ff0d:50cf:ffff:ffff:ffff:ffff:ffff:ffff
14ff0d:50d0::/28ff0d:50df:ffff:ffff:ffff:ffff:ffff:ffff
15ff0d:50e0::/28ff0d:50ef:ffff:ffff:ffff:ffff:ffff:ffff
16ff0d:50f0::/28ff0d:50ff:ffff:ffff:ffff:ffff:ffff:ffff
17ff0d:5100::/28ff0d:510f:ffff:ffff:ffff:ffff:ffff:ffff
18ff0d:5110::/28ff0d:511f:ffff:ffff:ffff:ffff:ffff:ffff
19ff0d:5120::/28ff0d:512f:ffff:ffff:ffff:ffff:ffff:ffff
20ff0d:5130::/28ff0d:513f:ffff:ffff:ffff:ffff:ffff:ffff
21ff0d:5140::/28ff0d:514f:ffff:ffff:ffff:ffff:ffff:ffff
22ff0d:5150::/28ff0d:515f:ffff:ffff:ffff:ffff:ffff:ffff
23ff0d:5160::/28ff0d:516f:ffff:ffff:ffff:ffff:ffff:ffff
24ff0d:5170::/28ff0d:517f:ffff:ffff:ffff:ffff:ffff:ffff
25ff0d:5180::/28ff0d:518f:ffff:ffff:ffff:ffff:ffff:ffff
26ff0d:5190::/28ff0d:519f:ffff:ffff:ffff:ffff:ffff:ffff
27ff0d:51a0::/28ff0d:51af:ffff:ffff:ffff:ffff:ffff:ffff
28ff0d:51b0::/28ff0d:51bf:ffff:ffff:ffff:ffff:ffff:ffff
29ff0d:51c0::/28ff0d:51cf:ffff:ffff:ffff:ffff:ffff:ffff
30ff0d:51d0::/28ff0d:51df:ffff:ffff:ffff:ffff:ffff:ffff
31ff0d:51e0::/28ff0d:51ef:ffff:ffff:ffff:ffff:ffff:ffff
32ff0d:51f0::/28ff0d:51ff:ffff:ffff:ffff:ffff:ffff:ffff
33ff0d:5200::/28ff0d:520f:ffff:ffff:ffff:ffff:ffff:ffff
34ff0d:5210::/28ff0d:521f:ffff:ffff:ffff:ffff:ffff:ffff
35ff0d:5220::/28ff0d:522f:ffff:ffff:ffff:ffff:ffff:ffff
36ff0d:5230::/28ff0d:523f:ffff:ffff:ffff:ffff:ffff:ffff
37ff0d:5240::/28ff0d:524f:ffff:ffff:ffff:ffff:ffff:ffff
38ff0d:5250::/28ff0d:525f:ffff:ffff:ffff:ffff:ffff:ffff
39ff0d:5260::/28ff0d:526f:ffff:ffff:ffff:ffff:ffff:ffff
40ff0d:5270::/28ff0d:527f:ffff:ffff:ffff:ffff:ffff:ffff
41ff0d:5280::/28ff0d:528f:ffff:ffff:ffff:ffff:ffff:ffff
42ff0d:5290::/28ff0d:529f:ffff:ffff:ffff:ffff:ffff:ffff
43ff0d:52a0::/28ff0d:52af:ffff:ffff:ffff:ffff:ffff:ffff
44ff0d:52b0::/28ff0d:52bf:ffff:ffff:ffff:ffff:ffff:ffff
45ff0d:52c0::/28ff0d:52cf:ffff:ffff:ffff:ffff:ffff:ffff
46ff0d:52d0::/28ff0d:52df:ffff:ffff:ffff:ffff:ffff:ffff
47ff0d:52e0::/28ff0d:52ef:ffff:ffff:ffff:ffff:ffff:ffff
48ff0d:52f0::/28ff0d:52ff:ffff:ffff:ffff:ffff:ffff:ffff
49ff0d:5300::/28ff0d:530f:ffff:ffff:ffff:ffff:ffff:ffff
50ff0d:5310::/28ff0d:531f:ffff:ffff:ffff:ffff:ffff:ffff
51ff0d:5320::/28ff0d:532f:ffff:ffff:ffff:ffff:ffff:ffff
52ff0d:5330::/28ff0d:533f:ffff:ffff:ffff:ffff:ffff:ffff
53ff0d:5340::/28ff0d:534f:ffff:ffff:ffff:ffff:ffff:ffff
54ff0d:5350::/28ff0d:535f:ffff:ffff:ffff:ffff:ffff:ffff
55ff0d:5360::/28ff0d:536f:ffff:ffff:ffff:ffff:ffff:ffff
56ff0d:5370::/28ff0d:537f:ffff:ffff:ffff:ffff:ffff:ffff
57ff0d:5380::/28ff0d:538f:ffff:ffff:ffff:ffff:ffff:ffff
58ff0d:5390::/28ff0d:539f:ffff:ffff:ffff:ffff:ffff:ffff
59ff0d:53a0::/28ff0d:53af:ffff:ffff:ffff:ffff:ffff:ffff
60ff0d:53b0::/28ff0d:53bf:ffff:ffff:ffff:ffff:ffff:ffff
61ff0d:53c0::/28ff0d:53cf:ffff:ffff:ffff:ffff:ffff:ffff
62ff0d:53d0::/28ff0d:53df:ffff:ffff:ffff:ffff:ffff:ffff
63ff0d:53e0::/28ff0d:53ef:ffff:ffff:ffff:ffff:ffff:ffff
64ff0d:53f0::/28ff0d:53ff:ffff:ffff:ffff:ffff:ffff:ffff
65ff0d:5400::/28ff0d:540f:ffff:ffff:ffff:ffff:ffff:ffff
66ff0d:5410::/28ff0d:541f:ffff:ffff:ffff:ffff:ffff:ffff
67ff0d:5420::/28ff0d:542f:ffff:ffff:ffff:ffff:ffff:ffff
68ff0d:5430::/28ff0d:543f:ffff:ffff:ffff:ffff:ffff:ffff
69ff0d:5440::/28ff0d:544f:ffff:ffff:ffff:ffff:ffff:ffff
70ff0d:5450::/28ff0d:545f:ffff:ffff:ffff:ffff:ffff:ffff
71ff0d:5460::/28ff0d:546f:ffff:ffff:ffff:ffff:ffff:ffff
72ff0d:5470::/28ff0d:547f:ffff:ffff:ffff:ffff:ffff:ffff
73ff0d:5480::/28ff0d:548f:ffff:ffff:ffff:ffff:ffff:ffff
74ff0d:5490::/28ff0d:549f:ffff:ffff:ffff:ffff:ffff:ffff
75ff0d:54a0::/28ff0d:54af:ffff:ffff:ffff:ffff:ffff:ffff
76ff0d:54b0::/28ff0d:54bf:ffff:ffff:ffff:ffff:ffff:ffff
77ff0d:54c0::/28ff0d:54cf:ffff:ffff:ffff:ffff:ffff:ffff
78ff0d:54d0::/28ff0d:54df:ffff:ffff:ffff:ffff:ffff:ffff
79ff0d:54e0::/28ff0d:54ef:ffff:ffff:ffff:ffff:ffff:ffff
80ff0d:54f0::/28ff0d:54ff:ffff:ffff:ffff:ffff:ffff:ffff
81ff0d:5500::/28ff0d:550f:ffff:ffff:ffff:ffff:ffff:ffff
82ff0d:5510::/28ff0d:551f:ffff:ffff:ffff:ffff:ffff:ffff
83ff0d:5520::/28ff0d:552f:ffff:ffff:ffff:ffff:ffff:ffff
84ff0d:5530::/28ff0d:553f:ffff:ffff:ffff:ffff:ffff:ffff
85ff0d:5540::/28ff0d:554f:ffff:ffff:ffff:ffff:ffff:ffff
86ff0d:5550::/28ff0d:555f:ffff:ffff:ffff:ffff:ffff:ffff
87ff0d:5560::/28ff0d:556f:ffff:ffff:ffff:ffff:ffff:ffff
88ff0d:5570::/28ff0d:557f:ffff:ffff:ffff:ffff:ffff:ffff
89ff0d:5580::/28ff0d:558f:ffff:ffff:ffff:ffff:ffff:ffff
90ff0d:5590::/28ff0d:559f:ffff:ffff:ffff:ffff:ffff:ffff
91ff0d:55a0::/28ff0d:55af:ffff:ffff:ffff:ffff:ffff:ffff
92ff0d:55b0::/28ff0d:55bf:ffff:ffff:ffff:ffff:ffff:ffff
93ff0d:55c0::/28ff0d:55cf:ffff:ffff:ffff:ffff:ffff:ffff
94ff0d:55d0::/28ff0d:55df:ffff:ffff:ffff:ffff:ffff:ffff
95ff0d:55e0::/28ff0d:55ef:ffff:ffff:ffff:ffff:ffff:ffff
96ff0d:55f0::/28ff0d:55ff:ffff:ffff:ffff:ffff:ffff:ffff
97ff0d:5600::/28ff0d:560f:ffff:ffff:ffff:ffff:ffff:ffff
98ff0d:5610::/28ff0d:561f:ffff:ffff:ffff:ffff:ffff:ffff
99ff0d:5620::/28ff0d:562f:ffff:ffff:ffff:ffff:ffff:ffff
100ff0d:5630::/28ff0d:563f:ffff:ffff:ffff:ffff:ffff:ffff
101ff0d:5640::/28ff0d:564f:ffff:ffff:ffff:ffff:ffff:ffff
102ff0d:5650::/28ff0d:565f:ffff:ffff:ffff:ffff:ffff:ffff
103ff0d:5660::/28ff0d:566f:ffff:ffff:ffff:ffff:ffff:ffff
104ff0d:5670::/28ff0d:567f:ffff:ffff:ffff:ffff:ffff:ffff
105ff0d:5680::/28ff0d:568f:ffff:ffff:ffff:ffff:ffff:ffff
106ff0d:5690::/28ff0d:569f:ffff:ffff:ffff:ffff:ffff:ffff
107ff0d:56a0::/28ff0d:56af:ffff:ffff:ffff:ffff:ffff:ffff
108ff0d:56b0::/28ff0d:56bf:ffff:ffff:ffff:ffff:ffff:ffff
109ff0d:56c0::/28ff0d:56cf:ffff:ffff:ffff:ffff:ffff:ffff
110ff0d:56d0::/28ff0d:56df:ffff:ffff:ffff:ffff:ffff:ffff
111ff0d:56e0::/28ff0d:56ef:ffff:ffff:ffff:ffff:ffff:ffff
112ff0d:56f0::/28ff0d:56ff:ffff:ffff:ffff:ffff:ffff:ffff
113ff0d:5700::/28ff0d:570f:ffff:ffff:ffff:ffff:ffff:ffff
114ff0d:5710::/28ff0d:571f:ffff:ffff:ffff:ffff:ffff:ffff
115ff0d:5720::/28ff0d:572f:ffff:ffff:ffff:ffff:ffff:ffff
116ff0d:5730::/28ff0d:573f:ffff:ffff:ffff:ffff:ffff:ffff
117ff0d:5740::/28ff0d:574f:ffff:ffff:ffff:ffff:ffff:ffff
118ff0d:5750::/28ff0d:575f:ffff:ffff:ffff:ffff:ffff:ffff
119ff0d:5760::/28ff0d:576f:ffff:ffff:ffff:ffff:ffff:ffff
120ff0d:5770::/28ff0d:577f:ffff:ffff:ffff:ffff:ffff:ffff
121ff0d:5780::/28ff0d:578f:ffff:ffff:ffff:ffff:ffff:ffff
122ff0d:5790::/28ff0d:579f:ffff:ffff:ffff:ffff:ffff:ffff
123ff0d:57a0::/28ff0d:57af:ffff:ffff:ffff:ffff:ffff:ffff
124ff0d:57b0::/28ff0d:57bf:ffff:ffff:ffff:ffff:ffff:ffff
125ff0d:57c0::/28ff0d:57cf:ffff:ffff:ffff:ffff:ffff:ffff
126ff0d:57d0::/28ff0d:57df:ffff:ffff:ffff:ffff:ffff:ffff
127ff0d:57e0::/28ff0d:57ef:ffff:ffff:ffff:ffff:ffff:ffff
128ff0d:57f0::/28ff0d:57ff:ffff:ffff:ffff:ffff:ffff:ffff
129ff0d:5800::/28ff0d:580f:ffff:ffff:ffff:ffff:ffff:ffff
130ff0d:5810::/28ff0d:581f:ffff:ffff:ffff:ffff:ffff:ffff
131ff0d:5820::/28ff0d:582f:ffff:ffff:ffff:ffff:ffff:ffff
132ff0d:5830::/28ff0d:583f:ffff:ffff:ffff:ffff:ffff:ffff
133ff0d:5840::/28ff0d:584f:ffff:ffff:ffff:ffff:ffff:ffff
134ff0d:5850::/28ff0d:585f:ffff:ffff:ffff:ffff:ffff:ffff
135ff0d:5860::/28ff0d:586f:ffff:ffff:ffff:ffff:ffff:ffff
136ff0d:5870::/28ff0d:587f:ffff:ffff:ffff:ffff:ffff:ffff
137ff0d:5880::/28ff0d:588f:ffff:ffff:ffff:ffff:ffff:ffff
138ff0d:5890::/28ff0d:589f:ffff:ffff:ffff:ffff:ffff:ffff
139ff0d:58a0::/28ff0d:58af:ffff:ffff:ffff:ffff:ffff:ffff
140ff0d:58b0::/28ff0d:58bf:ffff:ffff:ffff:ffff:ffff:ffff
141ff0d:58c0::/28ff0d:58cf:ffff:ffff:ffff:ffff:ffff:ffff
142ff0d:58d0::/28ff0d:58df:ffff:ffff:ffff:ffff:ffff:ffff
143ff0d:58e0::/28ff0d:58ef:ffff:ffff:ffff:ffff:ffff:ffff
144ff0d:58f0::/28ff0d:58ff:ffff:ffff:ffff:ffff:ffff:ffff
145ff0d:5900::/28ff0d:590f:ffff:ffff:ffff:ffff:ffff:ffff
146ff0d:5910::/28ff0d:591f:ffff:ffff:ffff:ffff:ffff:ffff
147ff0d:5920::/28ff0d:592f:ffff:ffff:ffff:ffff:ffff:ffff
148ff0d:5930::/28ff0d:593f:ffff:ffff:ffff:ffff:ffff:ffff
149ff0d:5940::/28ff0d:594f:ffff:ffff:ffff:ffff:ffff:ffff
150ff0d:5950::/28ff0d:595f:ffff:ffff:ffff:ffff:ffff:ffff
151ff0d:5960::/28ff0d:596f:ffff:ffff:ffff:ffff:ffff:ffff
152ff0d:5970::/28ff0d:597f:ffff:ffff:ffff:ffff:ffff:ffff
153ff0d:5980::/28ff0d:598f:ffff:ffff:ffff:ffff:ffff:ffff
154ff0d:5990::/28ff0d:599f:ffff:ffff:ffff:ffff:ffff:ffff
155ff0d:59a0::/28ff0d:59af:ffff:ffff:ffff:ffff:ffff:ffff
156ff0d:59b0::/28ff0d:59bf:ffff:ffff:ffff:ffff:ffff:ffff
157ff0d:59c0::/28ff0d:59cf:ffff:ffff:ffff:ffff:ffff:ffff
158ff0d:59d0::/28ff0d:59df:ffff:ffff:ffff:ffff:ffff:ffff
159ff0d:59e0::/28ff0d:59ef:ffff:ffff:ffff:ffff:ffff:ffff
160ff0d:59f0::/28ff0d:59ff:ffff:ffff:ffff:ffff:ffff:ffff
161ff0d:5a00::/28ff0d:5a0f:ffff:ffff:ffff:ffff:ffff:ffff
162ff0d:5a10::/28ff0d:5a1f:ffff:ffff:ffff:ffff:ffff:ffff
163ff0d:5a20::/28ff0d:5a2f:ffff:ffff:ffff:ffff:ffff:ffff
164ff0d:5a30::/28ff0d:5a3f:ffff:ffff:ffff:ffff:ffff:ffff
165ff0d:5a40::/28ff0d:5a4f:ffff:ffff:ffff:ffff:ffff:ffff
166ff0d:5a50::/28ff0d:5a5f:ffff:ffff:ffff:ffff:ffff:ffff
167ff0d:5a60::/28ff0d:5a6f:ffff:ffff:ffff:ffff:ffff:ffff
168ff0d:5a70::/28ff0d:5a7f:ffff:ffff:ffff:ffff:ffff:ffff
169ff0d:5a80::/28ff0d:5a8f:ffff:ffff:ffff:ffff:ffff:ffff
170ff0d:5a90::/28ff0d:5a9f:ffff:ffff:ffff:ffff:ffff:ffff
171ff0d:5aa0::/28ff0d:5aaf:ffff:ffff:ffff:ffff:ffff:ffff
172ff0d:5ab0::/28ff0d:5abf:ffff:ffff:ffff:ffff:ffff:ffff
173ff0d:5ac0::/28ff0d:5acf:ffff:ffff:ffff:ffff:ffff:ffff
174ff0d:5ad0::/28ff0d:5adf:ffff:ffff:ffff:ffff:ffff:ffff
175ff0d:5ae0::/28ff0d:5aef:ffff:ffff:ffff:ffff:ffff:ffff
176ff0d:5af0::/28ff0d:5aff:ffff:ffff:ffff:ffff:ffff:ffff
177ff0d:5b00::/28ff0d:5b0f:ffff:ffff:ffff:ffff:ffff:ffff
178ff0d:5b10::/28ff0d:5b1f:ffff:ffff:ffff:ffff:ffff:ffff
179ff0d:5b20::/28ff0d:5b2f:ffff:ffff:ffff:ffff:ffff:ffff
180ff0d:5b30::/28ff0d:5b3f:ffff:ffff:ffff:ffff:ffff:ffff
181ff0d:5b40::/28ff0d:5b4f:ffff:ffff:ffff:ffff:ffff:ffff
182ff0d:5b50::/28ff0d:5b5f:ffff:ffff:ffff:ffff:ffff:ffff
183ff0d:5b60::/28ff0d:5b6f:ffff:ffff:ffff:ffff:ffff:ffff
184ff0d:5b70::/28ff0d:5b7f:ffff:ffff:ffff:ffff:ffff:ffff
185ff0d:5b80::/28ff0d:5b8f:ffff:ffff:ffff:ffff:ffff:ffff
186ff0d:5b90::/28ff0d:5b9f:ffff:ffff:ffff:ffff:ffff:ffff
187ff0d:5ba0::/28ff0d:5baf:ffff:ffff:ffff:ffff:ffff:ffff
188ff0d:5bb0::/28ff0d:5bbf:ffff:ffff:ffff:ffff:ffff:ffff
189ff0d:5bc0::/28ff0d:5bcf:ffff:ffff:ffff:ffff:ffff:ffff
190ff0d:5bd0::/28ff0d:5bdf:ffff:ffff:ffff:ffff:ffff:ffff
191ff0d:5be0::/28ff0d:5bef:ffff:ffff:ffff:ffff:ffff:ffff
192ff0d:5bf0::/28ff0d:5bff:ffff:ffff:ffff:ffff:ffff:ffff
193ff0d:5c00::/28ff0d:5c0f:ffff:ffff:ffff:ffff:ffff:ffff
194ff0d:5c10::/28ff0d:5c1f:ffff:ffff:ffff:ffff:ffff:ffff
195ff0d:5c20::/28ff0d:5c2f:ffff:ffff:ffff:ffff:ffff:ffff
196ff0d:5c30::/28ff0d:5c3f:ffff:ffff:ffff:ffff:ffff:ffff
197ff0d:5c40::/28ff0d:5c4f:ffff:ffff:ffff:ffff:ffff:ffff
198ff0d:5c50::/28ff0d:5c5f:ffff:ffff:ffff:ffff:ffff:ffff
199ff0d:5c60::/28ff0d:5c6f:ffff:ffff:ffff:ffff:ffff:ffff
200ff0d:5c70::/28ff0d:5c7f:ffff:ffff:ffff:ffff:ffff:ffff
201ff0d:5c80::/28ff0d:5c8f:ffff:ffff:ffff:ffff:ffff:ffff
202ff0d:5c90::/28ff0d:5c9f:ffff:ffff:ffff:ffff:ffff:ffff
203ff0d:5ca0::/28ff0d:5caf:ffff:ffff:ffff:ffff:ffff:ffff
204ff0d:5cb0::/28ff0d:5cbf:ffff:ffff:ffff:ffff:ffff:ffff
205ff0d:5cc0::/28ff0d:5ccf:ffff:ffff:ffff:ffff:ffff:ffff
206ff0d:5cd0::/28ff0d:5cdf:ffff:ffff:ffff:ffff:ffff:ffff
207ff0d:5ce0::/28ff0d:5cef:ffff:ffff:ffff:ffff:ffff:ffff
208ff0d:5cf0::/28ff0d:5cff:ffff:ffff:ffff:ffff:ffff:ffff
209ff0d:5d00::/28ff0d:5d0f:ffff:ffff:ffff:ffff:ffff:ffff
210ff0d:5d10::/28ff0d:5d1f:ffff:ffff:ffff:ffff:ffff:ffff
211ff0d:5d20::/28ff0d:5d2f:ffff:ffff:ffff:ffff:ffff:ffff
212ff0d:5d30::/28ff0d:5d3f:ffff:ffff:ffff:ffff:ffff:ffff
213ff0d:5d40::/28ff0d:5d4f:ffff:ffff:ffff:ffff:ffff:ffff
214ff0d:5d50::/28ff0d:5d5f:ffff:ffff:ffff:ffff:ffff:ffff
215ff0d:5d60::/28ff0d:5d6f:ffff:ffff:ffff:ffff:ffff:ffff
216ff0d:5d70::/28ff0d:5d7f:ffff:ffff:ffff:ffff:ffff:ffff
217ff0d:5d80::/28ff0d:5d8f:ffff:ffff:ffff:ffff:ffff:ffff
218ff0d:5d90::/28ff0d:5d9f:ffff:ffff:ffff:ffff:ffff:ffff
219ff0d:5da0::/28ff0d:5daf:ffff:ffff:ffff:ffff:ffff:ffff
220ff0d:5db0::/28ff0d:5dbf:ffff:ffff:ffff:ffff:ffff:ffff
221ff0d:5dc0::/28ff0d:5dcf:ffff:ffff:ffff:ffff:ffff:ffff
222ff0d:5dd0::/28ff0d:5ddf:ffff:ffff:ffff:ffff:ffff:ffff
223ff0d:5de0::/28ff0d:5def:ffff:ffff:ffff:ffff:ffff:ffff
224ff0d:5df0::/28ff0d:5dff:ffff:ffff:ffff:ffff:ffff:ffff
225ff0d:5e00::/28ff0d:5e0f:ffff:ffff:ffff:ffff:ffff:ffff
226ff0d:5e10::/28ff0d:5e1f:ffff:ffff:ffff:ffff:ffff:ffff
227ff0d:5e20::/28ff0d:5e2f:ffff:ffff:ffff:ffff:ffff:ffff
228ff0d:5e30::/28ff0d:5e3f:ffff:ffff:ffff:ffff:ffff:ffff
229ff0d:5e40::/28ff0d:5e4f:ffff:ffff:ffff:ffff:ffff:ffff
230ff0d:5e50::/28ff0d:5e5f:ffff:ffff:ffff:ffff:ffff:ffff
231ff0d:5e60::/28ff0d:5e6f:ffff:ffff:ffff:ffff:ffff:ffff
232ff0d:5e70::/28ff0d:5e7f:ffff:ffff:ffff:ffff:ffff:ffff
233ff0d:5e80::/28ff0d:5e8f:ffff:ffff:ffff:ffff:ffff:ffff
234ff0d:5e90::/28ff0d:5e9f:ffff:ffff:ffff:ffff:ffff:ffff
235ff0d:5ea0::/28ff0d:5eaf:ffff:ffff:ffff:ffff:ffff:ffff
236ff0d:5eb0::/28ff0d:5ebf:ffff:ffff:ffff:ffff:ffff:ffff
237ff0d:5ec0::/28ff0d:5ecf:ffff:ffff:ffff:ffff:ffff:ffff
238ff0d:5ed0::/28ff0d:5edf:ffff:ffff:ffff:ffff:ffff:ffff
239ff0d:5ee0::/28ff0d:5eef:ffff:ffff:ffff:ffff:ffff:ffff
240ff0d:5ef0::/28ff0d:5eff:ffff:ffff:ffff:ffff:ffff:ffff
241ff0d:5f00::/28ff0d:5f0f:ffff:ffff:ffff:ffff:ffff:ffff
242ff0d:5f10::/28ff0d:5f1f:ffff:ffff:ffff:ffff:ffff:ffff
243ff0d:5f20::/28ff0d:5f2f:ffff:ffff:ffff:ffff:ffff:ffff
244ff0d:5f30::/28ff0d:5f3f:ffff:ffff:ffff:ffff:ffff:ffff
245ff0d:5f40::/28ff0d:5f4f:ffff:ffff:ffff:ffff:ffff:ffff
246ff0d:5f50::/28ff0d:5f5f:ffff:ffff:ffff:ffff:ffff:ffff
247ff0d:5f60::/28ff0d:5f6f:ffff:ffff:ffff:ffff:ffff:ffff
248ff0d:5f70::/28ff0d:5f7f:ffff:ffff:ffff:ffff:ffff:ffff
249ff0d:5f80::/28ff0d:5f8f:ffff:ffff:ffff:ffff:ffff:ffff
250ff0d:5f90::/28ff0d:5f9f:ffff:ffff:ffff:ffff:ffff:ffff
251ff0d:5fa0::/28ff0d:5faf:ffff:ffff:ffff:ffff:ffff:ffff
252ff0d:5fb0::/28ff0d:5fbf:ffff:ffff:ffff:ffff:ffff:ffff
253ff0d:5fc0::/28ff0d:5fcf:ffff:ffff:ffff:ffff:ffff:ffff
254ff0d:5fd0::/28ff0d:5fdf:ffff:ffff:ffff:ffff:ffff:ffff
255ff0d:5fe0::/28ff0d:5fef:ffff:ffff:ffff:ffff:ffff:ffff
256ff0d:5ff0::/28ff0d:5fff: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.