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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/20
Addresses2^108
/64 networks2^44
Network
ffdd::/20
First address
ffdd::
Last address
ffdd:fff: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
ffdd:0000:0000:0000:0000:0000:0000:0000
Type
Multicast ff00::/8
One-to-many traffic; replaces broadcast
Reverse DNS zone
0.d.d.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)

ffdd::/20 makes 256 subnets of /28.

Subnets
#SubnetLast address
1ffdd::/28ffdd:f:ffff:ffff:ffff:ffff:ffff:ffff
2ffdd:10::/28ffdd:1f:ffff:ffff:ffff:ffff:ffff:ffff
3ffdd:20::/28ffdd:2f:ffff:ffff:ffff:ffff:ffff:ffff
4ffdd:30::/28ffdd:3f:ffff:ffff:ffff:ffff:ffff:ffff
5ffdd:40::/28ffdd:4f:ffff:ffff:ffff:ffff:ffff:ffff
6ffdd:50::/28ffdd:5f:ffff:ffff:ffff:ffff:ffff:ffff
7ffdd:60::/28ffdd:6f:ffff:ffff:ffff:ffff:ffff:ffff
8ffdd:70::/28ffdd:7f:ffff:ffff:ffff:ffff:ffff:ffff
9ffdd:80::/28ffdd:8f:ffff:ffff:ffff:ffff:ffff:ffff
10ffdd:90::/28ffdd:9f:ffff:ffff:ffff:ffff:ffff:ffff
11ffdd:a0::/28ffdd:af:ffff:ffff:ffff:ffff:ffff:ffff
12ffdd:b0::/28ffdd:bf:ffff:ffff:ffff:ffff:ffff:ffff
13ffdd:c0::/28ffdd:cf:ffff:ffff:ffff:ffff:ffff:ffff
14ffdd:d0::/28ffdd:df:ffff:ffff:ffff:ffff:ffff:ffff
15ffdd:e0::/28ffdd:ef:ffff:ffff:ffff:ffff:ffff:ffff
16ffdd:f0::/28ffdd:ff:ffff:ffff:ffff:ffff:ffff:ffff
17ffdd:100::/28ffdd:10f:ffff:ffff:ffff:ffff:ffff:ffff
18ffdd:110::/28ffdd:11f:ffff:ffff:ffff:ffff:ffff:ffff
19ffdd:120::/28ffdd:12f:ffff:ffff:ffff:ffff:ffff:ffff
20ffdd:130::/28ffdd:13f:ffff:ffff:ffff:ffff:ffff:ffff
21ffdd:140::/28ffdd:14f:ffff:ffff:ffff:ffff:ffff:ffff
22ffdd:150::/28ffdd:15f:ffff:ffff:ffff:ffff:ffff:ffff
23ffdd:160::/28ffdd:16f:ffff:ffff:ffff:ffff:ffff:ffff
24ffdd:170::/28ffdd:17f:ffff:ffff:ffff:ffff:ffff:ffff
25ffdd:180::/28ffdd:18f:ffff:ffff:ffff:ffff:ffff:ffff
26ffdd:190::/28ffdd:19f:ffff:ffff:ffff:ffff:ffff:ffff
27ffdd:1a0::/28ffdd:1af:ffff:ffff:ffff:ffff:ffff:ffff
28ffdd:1b0::/28ffdd:1bf:ffff:ffff:ffff:ffff:ffff:ffff
29ffdd:1c0::/28ffdd:1cf:ffff:ffff:ffff:ffff:ffff:ffff
30ffdd:1d0::/28ffdd:1df:ffff:ffff:ffff:ffff:ffff:ffff
31ffdd:1e0::/28ffdd:1ef:ffff:ffff:ffff:ffff:ffff:ffff
32ffdd:1f0::/28ffdd:1ff:ffff:ffff:ffff:ffff:ffff:ffff
33ffdd:200::/28ffdd:20f:ffff:ffff:ffff:ffff:ffff:ffff
34ffdd:210::/28ffdd:21f:ffff:ffff:ffff:ffff:ffff:ffff
35ffdd:220::/28ffdd:22f:ffff:ffff:ffff:ffff:ffff:ffff
36ffdd:230::/28ffdd:23f:ffff:ffff:ffff:ffff:ffff:ffff
37ffdd:240::/28ffdd:24f:ffff:ffff:ffff:ffff:ffff:ffff
38ffdd:250::/28ffdd:25f:ffff:ffff:ffff:ffff:ffff:ffff
39ffdd:260::/28ffdd:26f:ffff:ffff:ffff:ffff:ffff:ffff
40ffdd:270::/28ffdd:27f:ffff:ffff:ffff:ffff:ffff:ffff
41ffdd:280::/28ffdd:28f:ffff:ffff:ffff:ffff:ffff:ffff
42ffdd:290::/28ffdd:29f:ffff:ffff:ffff:ffff:ffff:ffff
43ffdd:2a0::/28ffdd:2af:ffff:ffff:ffff:ffff:ffff:ffff
44ffdd:2b0::/28ffdd:2bf:ffff:ffff:ffff:ffff:ffff:ffff
45ffdd:2c0::/28ffdd:2cf:ffff:ffff:ffff:ffff:ffff:ffff
46ffdd:2d0::/28ffdd:2df:ffff:ffff:ffff:ffff:ffff:ffff
47ffdd:2e0::/28ffdd:2ef:ffff:ffff:ffff:ffff:ffff:ffff
48ffdd:2f0::/28ffdd:2ff:ffff:ffff:ffff:ffff:ffff:ffff
49ffdd:300::/28ffdd:30f:ffff:ffff:ffff:ffff:ffff:ffff
50ffdd:310::/28ffdd:31f:ffff:ffff:ffff:ffff:ffff:ffff
51ffdd:320::/28ffdd:32f:ffff:ffff:ffff:ffff:ffff:ffff
52ffdd:330::/28ffdd:33f:ffff:ffff:ffff:ffff:ffff:ffff
53ffdd:340::/28ffdd:34f:ffff:ffff:ffff:ffff:ffff:ffff
54ffdd:350::/28ffdd:35f:ffff:ffff:ffff:ffff:ffff:ffff
55ffdd:360::/28ffdd:36f:ffff:ffff:ffff:ffff:ffff:ffff
56ffdd:370::/28ffdd:37f:ffff:ffff:ffff:ffff:ffff:ffff
57ffdd:380::/28ffdd:38f:ffff:ffff:ffff:ffff:ffff:ffff
58ffdd:390::/28ffdd:39f:ffff:ffff:ffff:ffff:ffff:ffff
59ffdd:3a0::/28ffdd:3af:ffff:ffff:ffff:ffff:ffff:ffff
60ffdd:3b0::/28ffdd:3bf:ffff:ffff:ffff:ffff:ffff:ffff
61ffdd:3c0::/28ffdd:3cf:ffff:ffff:ffff:ffff:ffff:ffff
62ffdd:3d0::/28ffdd:3df:ffff:ffff:ffff:ffff:ffff:ffff
63ffdd:3e0::/28ffdd:3ef:ffff:ffff:ffff:ffff:ffff:ffff
64ffdd:3f0::/28ffdd:3ff:ffff:ffff:ffff:ffff:ffff:ffff
65ffdd:400::/28ffdd:40f:ffff:ffff:ffff:ffff:ffff:ffff
66ffdd:410::/28ffdd:41f:ffff:ffff:ffff:ffff:ffff:ffff
67ffdd:420::/28ffdd:42f:ffff:ffff:ffff:ffff:ffff:ffff
68ffdd:430::/28ffdd:43f:ffff:ffff:ffff:ffff:ffff:ffff
69ffdd:440::/28ffdd:44f:ffff:ffff:ffff:ffff:ffff:ffff
70ffdd:450::/28ffdd:45f:ffff:ffff:ffff:ffff:ffff:ffff
71ffdd:460::/28ffdd:46f:ffff:ffff:ffff:ffff:ffff:ffff
72ffdd:470::/28ffdd:47f:ffff:ffff:ffff:ffff:ffff:ffff
73ffdd:480::/28ffdd:48f:ffff:ffff:ffff:ffff:ffff:ffff
74ffdd:490::/28ffdd:49f:ffff:ffff:ffff:ffff:ffff:ffff
75ffdd:4a0::/28ffdd:4af:ffff:ffff:ffff:ffff:ffff:ffff
76ffdd:4b0::/28ffdd:4bf:ffff:ffff:ffff:ffff:ffff:ffff
77ffdd:4c0::/28ffdd:4cf:ffff:ffff:ffff:ffff:ffff:ffff
78ffdd:4d0::/28ffdd:4df:ffff:ffff:ffff:ffff:ffff:ffff
79ffdd:4e0::/28ffdd:4ef:ffff:ffff:ffff:ffff:ffff:ffff
80ffdd:4f0::/28ffdd:4ff:ffff:ffff:ffff:ffff:ffff:ffff
81ffdd:500::/28ffdd:50f:ffff:ffff:ffff:ffff:ffff:ffff
82ffdd:510::/28ffdd:51f:ffff:ffff:ffff:ffff:ffff:ffff
83ffdd:520::/28ffdd:52f:ffff:ffff:ffff:ffff:ffff:ffff
84ffdd:530::/28ffdd:53f:ffff:ffff:ffff:ffff:ffff:ffff
85ffdd:540::/28ffdd:54f:ffff:ffff:ffff:ffff:ffff:ffff
86ffdd:550::/28ffdd:55f:ffff:ffff:ffff:ffff:ffff:ffff
87ffdd:560::/28ffdd:56f:ffff:ffff:ffff:ffff:ffff:ffff
88ffdd:570::/28ffdd:57f:ffff:ffff:ffff:ffff:ffff:ffff
89ffdd:580::/28ffdd:58f:ffff:ffff:ffff:ffff:ffff:ffff
90ffdd:590::/28ffdd:59f:ffff:ffff:ffff:ffff:ffff:ffff
91ffdd:5a0::/28ffdd:5af:ffff:ffff:ffff:ffff:ffff:ffff
92ffdd:5b0::/28ffdd:5bf:ffff:ffff:ffff:ffff:ffff:ffff
93ffdd:5c0::/28ffdd:5cf:ffff:ffff:ffff:ffff:ffff:ffff
94ffdd:5d0::/28ffdd:5df:ffff:ffff:ffff:ffff:ffff:ffff
95ffdd:5e0::/28ffdd:5ef:ffff:ffff:ffff:ffff:ffff:ffff
96ffdd:5f0::/28ffdd:5ff:ffff:ffff:ffff:ffff:ffff:ffff
97ffdd:600::/28ffdd:60f:ffff:ffff:ffff:ffff:ffff:ffff
98ffdd:610::/28ffdd:61f:ffff:ffff:ffff:ffff:ffff:ffff
99ffdd:620::/28ffdd:62f:ffff:ffff:ffff:ffff:ffff:ffff
100ffdd:630::/28ffdd:63f:ffff:ffff:ffff:ffff:ffff:ffff
101ffdd:640::/28ffdd:64f:ffff:ffff:ffff:ffff:ffff:ffff
102ffdd:650::/28ffdd:65f:ffff:ffff:ffff:ffff:ffff:ffff
103ffdd:660::/28ffdd:66f:ffff:ffff:ffff:ffff:ffff:ffff
104ffdd:670::/28ffdd:67f:ffff:ffff:ffff:ffff:ffff:ffff
105ffdd:680::/28ffdd:68f:ffff:ffff:ffff:ffff:ffff:ffff
106ffdd:690::/28ffdd:69f:ffff:ffff:ffff:ffff:ffff:ffff
107ffdd:6a0::/28ffdd:6af:ffff:ffff:ffff:ffff:ffff:ffff
108ffdd:6b0::/28ffdd:6bf:ffff:ffff:ffff:ffff:ffff:ffff
109ffdd:6c0::/28ffdd:6cf:ffff:ffff:ffff:ffff:ffff:ffff
110ffdd:6d0::/28ffdd:6df:ffff:ffff:ffff:ffff:ffff:ffff
111ffdd:6e0::/28ffdd:6ef:ffff:ffff:ffff:ffff:ffff:ffff
112ffdd:6f0::/28ffdd:6ff:ffff:ffff:ffff:ffff:ffff:ffff
113ffdd:700::/28ffdd:70f:ffff:ffff:ffff:ffff:ffff:ffff
114ffdd:710::/28ffdd:71f:ffff:ffff:ffff:ffff:ffff:ffff
115ffdd:720::/28ffdd:72f:ffff:ffff:ffff:ffff:ffff:ffff
116ffdd:730::/28ffdd:73f:ffff:ffff:ffff:ffff:ffff:ffff
117ffdd:740::/28ffdd:74f:ffff:ffff:ffff:ffff:ffff:ffff
118ffdd:750::/28ffdd:75f:ffff:ffff:ffff:ffff:ffff:ffff
119ffdd:760::/28ffdd:76f:ffff:ffff:ffff:ffff:ffff:ffff
120ffdd:770::/28ffdd:77f:ffff:ffff:ffff:ffff:ffff:ffff
121ffdd:780::/28ffdd:78f:ffff:ffff:ffff:ffff:ffff:ffff
122ffdd:790::/28ffdd:79f:ffff:ffff:ffff:ffff:ffff:ffff
123ffdd:7a0::/28ffdd:7af:ffff:ffff:ffff:ffff:ffff:ffff
124ffdd:7b0::/28ffdd:7bf:ffff:ffff:ffff:ffff:ffff:ffff
125ffdd:7c0::/28ffdd:7cf:ffff:ffff:ffff:ffff:ffff:ffff
126ffdd:7d0::/28ffdd:7df:ffff:ffff:ffff:ffff:ffff:ffff
127ffdd:7e0::/28ffdd:7ef:ffff:ffff:ffff:ffff:ffff:ffff
128ffdd:7f0::/28ffdd:7ff:ffff:ffff:ffff:ffff:ffff:ffff
129ffdd:800::/28ffdd:80f:ffff:ffff:ffff:ffff:ffff:ffff
130ffdd:810::/28ffdd:81f:ffff:ffff:ffff:ffff:ffff:ffff
131ffdd:820::/28ffdd:82f:ffff:ffff:ffff:ffff:ffff:ffff
132ffdd:830::/28ffdd:83f:ffff:ffff:ffff:ffff:ffff:ffff
133ffdd:840::/28ffdd:84f:ffff:ffff:ffff:ffff:ffff:ffff
134ffdd:850::/28ffdd:85f:ffff:ffff:ffff:ffff:ffff:ffff
135ffdd:860::/28ffdd:86f:ffff:ffff:ffff:ffff:ffff:ffff
136ffdd:870::/28ffdd:87f:ffff:ffff:ffff:ffff:ffff:ffff
137ffdd:880::/28ffdd:88f:ffff:ffff:ffff:ffff:ffff:ffff
138ffdd:890::/28ffdd:89f:ffff:ffff:ffff:ffff:ffff:ffff
139ffdd:8a0::/28ffdd:8af:ffff:ffff:ffff:ffff:ffff:ffff
140ffdd:8b0::/28ffdd:8bf:ffff:ffff:ffff:ffff:ffff:ffff
141ffdd:8c0::/28ffdd:8cf:ffff:ffff:ffff:ffff:ffff:ffff
142ffdd:8d0::/28ffdd:8df:ffff:ffff:ffff:ffff:ffff:ffff
143ffdd:8e0::/28ffdd:8ef:ffff:ffff:ffff:ffff:ffff:ffff
144ffdd:8f0::/28ffdd:8ff:ffff:ffff:ffff:ffff:ffff:ffff
145ffdd:900::/28ffdd:90f:ffff:ffff:ffff:ffff:ffff:ffff
146ffdd:910::/28ffdd:91f:ffff:ffff:ffff:ffff:ffff:ffff
147ffdd:920::/28ffdd:92f:ffff:ffff:ffff:ffff:ffff:ffff
148ffdd:930::/28ffdd:93f:ffff:ffff:ffff:ffff:ffff:ffff
149ffdd:940::/28ffdd:94f:ffff:ffff:ffff:ffff:ffff:ffff
150ffdd:950::/28ffdd:95f:ffff:ffff:ffff:ffff:ffff:ffff
151ffdd:960::/28ffdd:96f:ffff:ffff:ffff:ffff:ffff:ffff
152ffdd:970::/28ffdd:97f:ffff:ffff:ffff:ffff:ffff:ffff
153ffdd:980::/28ffdd:98f:ffff:ffff:ffff:ffff:ffff:ffff
154ffdd:990::/28ffdd:99f:ffff:ffff:ffff:ffff:ffff:ffff
155ffdd:9a0::/28ffdd:9af:ffff:ffff:ffff:ffff:ffff:ffff
156ffdd:9b0::/28ffdd:9bf:ffff:ffff:ffff:ffff:ffff:ffff
157ffdd:9c0::/28ffdd:9cf:ffff:ffff:ffff:ffff:ffff:ffff
158ffdd:9d0::/28ffdd:9df:ffff:ffff:ffff:ffff:ffff:ffff
159ffdd:9e0::/28ffdd:9ef:ffff:ffff:ffff:ffff:ffff:ffff
160ffdd:9f0::/28ffdd:9ff:ffff:ffff:ffff:ffff:ffff:ffff
161ffdd:a00::/28ffdd:a0f:ffff:ffff:ffff:ffff:ffff:ffff
162ffdd:a10::/28ffdd:a1f:ffff:ffff:ffff:ffff:ffff:ffff
163ffdd:a20::/28ffdd:a2f:ffff:ffff:ffff:ffff:ffff:ffff
164ffdd:a30::/28ffdd:a3f:ffff:ffff:ffff:ffff:ffff:ffff
165ffdd:a40::/28ffdd:a4f:ffff:ffff:ffff:ffff:ffff:ffff
166ffdd:a50::/28ffdd:a5f:ffff:ffff:ffff:ffff:ffff:ffff
167ffdd:a60::/28ffdd:a6f:ffff:ffff:ffff:ffff:ffff:ffff
168ffdd:a70::/28ffdd:a7f:ffff:ffff:ffff:ffff:ffff:ffff
169ffdd:a80::/28ffdd:a8f:ffff:ffff:ffff:ffff:ffff:ffff
170ffdd:a90::/28ffdd:a9f:ffff:ffff:ffff:ffff:ffff:ffff
171ffdd:aa0::/28ffdd:aaf:ffff:ffff:ffff:ffff:ffff:ffff
172ffdd:ab0::/28ffdd:abf:ffff:ffff:ffff:ffff:ffff:ffff
173ffdd:ac0::/28ffdd:acf:ffff:ffff:ffff:ffff:ffff:ffff
174ffdd:ad0::/28ffdd:adf:ffff:ffff:ffff:ffff:ffff:ffff
175ffdd:ae0::/28ffdd:aef:ffff:ffff:ffff:ffff:ffff:ffff
176ffdd:af0::/28ffdd:aff:ffff:ffff:ffff:ffff:ffff:ffff
177ffdd:b00::/28ffdd:b0f:ffff:ffff:ffff:ffff:ffff:ffff
178ffdd:b10::/28ffdd:b1f:ffff:ffff:ffff:ffff:ffff:ffff
179ffdd:b20::/28ffdd:b2f:ffff:ffff:ffff:ffff:ffff:ffff
180ffdd:b30::/28ffdd:b3f:ffff:ffff:ffff:ffff:ffff:ffff
181ffdd:b40::/28ffdd:b4f:ffff:ffff:ffff:ffff:ffff:ffff
182ffdd:b50::/28ffdd:b5f:ffff:ffff:ffff:ffff:ffff:ffff
183ffdd:b60::/28ffdd:b6f:ffff:ffff:ffff:ffff:ffff:ffff
184ffdd:b70::/28ffdd:b7f:ffff:ffff:ffff:ffff:ffff:ffff
185ffdd:b80::/28ffdd:b8f:ffff:ffff:ffff:ffff:ffff:ffff
186ffdd:b90::/28ffdd:b9f:ffff:ffff:ffff:ffff:ffff:ffff
187ffdd:ba0::/28ffdd:baf:ffff:ffff:ffff:ffff:ffff:ffff
188ffdd:bb0::/28ffdd:bbf:ffff:ffff:ffff:ffff:ffff:ffff
189ffdd:bc0::/28ffdd:bcf:ffff:ffff:ffff:ffff:ffff:ffff
190ffdd:bd0::/28ffdd:bdf:ffff:ffff:ffff:ffff:ffff:ffff
191ffdd:be0::/28ffdd:bef:ffff:ffff:ffff:ffff:ffff:ffff
192ffdd:bf0::/28ffdd:bff:ffff:ffff:ffff:ffff:ffff:ffff
193ffdd:c00::/28ffdd:c0f:ffff:ffff:ffff:ffff:ffff:ffff
194ffdd:c10::/28ffdd:c1f:ffff:ffff:ffff:ffff:ffff:ffff
195ffdd:c20::/28ffdd:c2f:ffff:ffff:ffff:ffff:ffff:ffff
196ffdd:c30::/28ffdd:c3f:ffff:ffff:ffff:ffff:ffff:ffff
197ffdd:c40::/28ffdd:c4f:ffff:ffff:ffff:ffff:ffff:ffff
198ffdd:c50::/28ffdd:c5f:ffff:ffff:ffff:ffff:ffff:ffff
199ffdd:c60::/28ffdd:c6f:ffff:ffff:ffff:ffff:ffff:ffff
200ffdd:c70::/28ffdd:c7f:ffff:ffff:ffff:ffff:ffff:ffff
201ffdd:c80::/28ffdd:c8f:ffff:ffff:ffff:ffff:ffff:ffff
202ffdd:c90::/28ffdd:c9f:ffff:ffff:ffff:ffff:ffff:ffff
203ffdd:ca0::/28ffdd:caf:ffff:ffff:ffff:ffff:ffff:ffff
204ffdd:cb0::/28ffdd:cbf:ffff:ffff:ffff:ffff:ffff:ffff
205ffdd:cc0::/28ffdd:ccf:ffff:ffff:ffff:ffff:ffff:ffff
206ffdd:cd0::/28ffdd:cdf:ffff:ffff:ffff:ffff:ffff:ffff
207ffdd:ce0::/28ffdd:cef:ffff:ffff:ffff:ffff:ffff:ffff
208ffdd:cf0::/28ffdd:cff:ffff:ffff:ffff:ffff:ffff:ffff
209ffdd:d00::/28ffdd:d0f:ffff:ffff:ffff:ffff:ffff:ffff
210ffdd:d10::/28ffdd:d1f:ffff:ffff:ffff:ffff:ffff:ffff
211ffdd:d20::/28ffdd:d2f:ffff:ffff:ffff:ffff:ffff:ffff
212ffdd:d30::/28ffdd:d3f:ffff:ffff:ffff:ffff:ffff:ffff
213ffdd:d40::/28ffdd:d4f:ffff:ffff:ffff:ffff:ffff:ffff
214ffdd:d50::/28ffdd:d5f:ffff:ffff:ffff:ffff:ffff:ffff
215ffdd:d60::/28ffdd:d6f:ffff:ffff:ffff:ffff:ffff:ffff
216ffdd:d70::/28ffdd:d7f:ffff:ffff:ffff:ffff:ffff:ffff
217ffdd:d80::/28ffdd:d8f:ffff:ffff:ffff:ffff:ffff:ffff
218ffdd:d90::/28ffdd:d9f:ffff:ffff:ffff:ffff:ffff:ffff
219ffdd:da0::/28ffdd:daf:ffff:ffff:ffff:ffff:ffff:ffff
220ffdd:db0::/28ffdd:dbf:ffff:ffff:ffff:ffff:ffff:ffff
221ffdd:dc0::/28ffdd:dcf:ffff:ffff:ffff:ffff:ffff:ffff
222ffdd:dd0::/28ffdd:ddf:ffff:ffff:ffff:ffff:ffff:ffff
223ffdd:de0::/28ffdd:def:ffff:ffff:ffff:ffff:ffff:ffff
224ffdd:df0::/28ffdd:dff:ffff:ffff:ffff:ffff:ffff:ffff
225ffdd:e00::/28ffdd:e0f:ffff:ffff:ffff:ffff:ffff:ffff
226ffdd:e10::/28ffdd:e1f:ffff:ffff:ffff:ffff:ffff:ffff
227ffdd:e20::/28ffdd:e2f:ffff:ffff:ffff:ffff:ffff:ffff
228ffdd:e30::/28ffdd:e3f:ffff:ffff:ffff:ffff:ffff:ffff
229ffdd:e40::/28ffdd:e4f:ffff:ffff:ffff:ffff:ffff:ffff
230ffdd:e50::/28ffdd:e5f:ffff:ffff:ffff:ffff:ffff:ffff
231ffdd:e60::/28ffdd:e6f:ffff:ffff:ffff:ffff:ffff:ffff
232ffdd:e70::/28ffdd:e7f:ffff:ffff:ffff:ffff:ffff:ffff
233ffdd:e80::/28ffdd:e8f:ffff:ffff:ffff:ffff:ffff:ffff
234ffdd:e90::/28ffdd:e9f:ffff:ffff:ffff:ffff:ffff:ffff
235ffdd:ea0::/28ffdd:eaf:ffff:ffff:ffff:ffff:ffff:ffff
236ffdd:eb0::/28ffdd:ebf:ffff:ffff:ffff:ffff:ffff:ffff
237ffdd:ec0::/28ffdd:ecf:ffff:ffff:ffff:ffff:ffff:ffff
238ffdd:ed0::/28ffdd:edf:ffff:ffff:ffff:ffff:ffff:ffff
239ffdd:ee0::/28ffdd:eef:ffff:ffff:ffff:ffff:ffff:ffff
240ffdd:ef0::/28ffdd:eff:ffff:ffff:ffff:ffff:ffff:ffff
241ffdd:f00::/28ffdd:f0f:ffff:ffff:ffff:ffff:ffff:ffff
242ffdd:f10::/28ffdd:f1f:ffff:ffff:ffff:ffff:ffff:ffff
243ffdd:f20::/28ffdd:f2f:ffff:ffff:ffff:ffff:ffff:ffff
244ffdd:f30::/28ffdd:f3f:ffff:ffff:ffff:ffff:ffff:ffff
245ffdd:f40::/28ffdd:f4f:ffff:ffff:ffff:ffff:ffff:ffff
246ffdd:f50::/28ffdd:f5f:ffff:ffff:ffff:ffff:ffff:ffff
247ffdd:f60::/28ffdd:f6f:ffff:ffff:ffff:ffff:ffff:ffff
248ffdd:f70::/28ffdd:f7f:ffff:ffff:ffff:ffff:ffff:ffff
249ffdd:f80::/28ffdd:f8f:ffff:ffff:ffff:ffff:ffff:ffff
250ffdd:f90::/28ffdd:f9f:ffff:ffff:ffff:ffff:ffff:ffff
251ffdd:fa0::/28ffdd:faf:ffff:ffff:ffff:ffff:ffff:ffff
252ffdd:fb0::/28ffdd:fbf:ffff:ffff:ffff:ffff:ffff:ffff
253ffdd:fc0::/28ffdd:fcf:ffff:ffff:ffff:ffff:ffff:ffff
254ffdd:fd0::/28ffdd:fdf:ffff:ffff:ffff:ffff:ffff:ffff
255ffdd:fe0::/28ffdd:fef:ffff:ffff:ffff:ffff:ffff:ffff
256ffdd:ff0::/28ffdd:fff: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.