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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
ffb5::/16
First address
ffb5::
Last address
ffb5: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
ffb5:0000:0000:0000:0000:0000:0000:0000
Type
Multicast ff00::/8
One-to-many traffic; replaces broadcast
Reverse DNS zone
5.b.f.f.ip6.arpa
Split into smaller subnets/28
/17 (2)/18 (4)/19 (8)/20 (16)/24 (256)/28 (4,096)/32 (65,536)

ffb5::/16 makes 4,096 subnets of /28; the first 256 are listed.

Subnets
#SubnetLast address
1ffb5::/28ffb5:f:ffff:ffff:ffff:ffff:ffff:ffff
2ffb5:10::/28ffb5:1f:ffff:ffff:ffff:ffff:ffff:ffff
3ffb5:20::/28ffb5:2f:ffff:ffff:ffff:ffff:ffff:ffff
4ffb5:30::/28ffb5:3f:ffff:ffff:ffff:ffff:ffff:ffff
5ffb5:40::/28ffb5:4f:ffff:ffff:ffff:ffff:ffff:ffff
6ffb5:50::/28ffb5:5f:ffff:ffff:ffff:ffff:ffff:ffff
7ffb5:60::/28ffb5:6f:ffff:ffff:ffff:ffff:ffff:ffff
8ffb5:70::/28ffb5:7f:ffff:ffff:ffff:ffff:ffff:ffff
9ffb5:80::/28ffb5:8f:ffff:ffff:ffff:ffff:ffff:ffff
10ffb5:90::/28ffb5:9f:ffff:ffff:ffff:ffff:ffff:ffff
11ffb5:a0::/28ffb5:af:ffff:ffff:ffff:ffff:ffff:ffff
12ffb5:b0::/28ffb5:bf:ffff:ffff:ffff:ffff:ffff:ffff
13ffb5:c0::/28ffb5:cf:ffff:ffff:ffff:ffff:ffff:ffff
14ffb5:d0::/28ffb5:df:ffff:ffff:ffff:ffff:ffff:ffff
15ffb5:e0::/28ffb5:ef:ffff:ffff:ffff:ffff:ffff:ffff
16ffb5:f0::/28ffb5:ff:ffff:ffff:ffff:ffff:ffff:ffff
17ffb5:100::/28ffb5:10f:ffff:ffff:ffff:ffff:ffff:ffff
18ffb5:110::/28ffb5:11f:ffff:ffff:ffff:ffff:ffff:ffff
19ffb5:120::/28ffb5:12f:ffff:ffff:ffff:ffff:ffff:ffff
20ffb5:130::/28ffb5:13f:ffff:ffff:ffff:ffff:ffff:ffff
21ffb5:140::/28ffb5:14f:ffff:ffff:ffff:ffff:ffff:ffff
22ffb5:150::/28ffb5:15f:ffff:ffff:ffff:ffff:ffff:ffff
23ffb5:160::/28ffb5:16f:ffff:ffff:ffff:ffff:ffff:ffff
24ffb5:170::/28ffb5:17f:ffff:ffff:ffff:ffff:ffff:ffff
25ffb5:180::/28ffb5:18f:ffff:ffff:ffff:ffff:ffff:ffff
26ffb5:190::/28ffb5:19f:ffff:ffff:ffff:ffff:ffff:ffff
27ffb5:1a0::/28ffb5:1af:ffff:ffff:ffff:ffff:ffff:ffff
28ffb5:1b0::/28ffb5:1bf:ffff:ffff:ffff:ffff:ffff:ffff
29ffb5:1c0::/28ffb5:1cf:ffff:ffff:ffff:ffff:ffff:ffff
30ffb5:1d0::/28ffb5:1df:ffff:ffff:ffff:ffff:ffff:ffff
31ffb5:1e0::/28ffb5:1ef:ffff:ffff:ffff:ffff:ffff:ffff
32ffb5:1f0::/28ffb5:1ff:ffff:ffff:ffff:ffff:ffff:ffff
33ffb5:200::/28ffb5:20f:ffff:ffff:ffff:ffff:ffff:ffff
34ffb5:210::/28ffb5:21f:ffff:ffff:ffff:ffff:ffff:ffff
35ffb5:220::/28ffb5:22f:ffff:ffff:ffff:ffff:ffff:ffff
36ffb5:230::/28ffb5:23f:ffff:ffff:ffff:ffff:ffff:ffff
37ffb5:240::/28ffb5:24f:ffff:ffff:ffff:ffff:ffff:ffff
38ffb5:250::/28ffb5:25f:ffff:ffff:ffff:ffff:ffff:ffff
39ffb5:260::/28ffb5:26f:ffff:ffff:ffff:ffff:ffff:ffff
40ffb5:270::/28ffb5:27f:ffff:ffff:ffff:ffff:ffff:ffff
41ffb5:280::/28ffb5:28f:ffff:ffff:ffff:ffff:ffff:ffff
42ffb5:290::/28ffb5:29f:ffff:ffff:ffff:ffff:ffff:ffff
43ffb5:2a0::/28ffb5:2af:ffff:ffff:ffff:ffff:ffff:ffff
44ffb5:2b0::/28ffb5:2bf:ffff:ffff:ffff:ffff:ffff:ffff
45ffb5:2c0::/28ffb5:2cf:ffff:ffff:ffff:ffff:ffff:ffff
46ffb5:2d0::/28ffb5:2df:ffff:ffff:ffff:ffff:ffff:ffff
47ffb5:2e0::/28ffb5:2ef:ffff:ffff:ffff:ffff:ffff:ffff
48ffb5:2f0::/28ffb5:2ff:ffff:ffff:ffff:ffff:ffff:ffff
49ffb5:300::/28ffb5:30f:ffff:ffff:ffff:ffff:ffff:ffff
50ffb5:310::/28ffb5:31f:ffff:ffff:ffff:ffff:ffff:ffff
51ffb5:320::/28ffb5:32f:ffff:ffff:ffff:ffff:ffff:ffff
52ffb5:330::/28ffb5:33f:ffff:ffff:ffff:ffff:ffff:ffff
53ffb5:340::/28ffb5:34f:ffff:ffff:ffff:ffff:ffff:ffff
54ffb5:350::/28ffb5:35f:ffff:ffff:ffff:ffff:ffff:ffff
55ffb5:360::/28ffb5:36f:ffff:ffff:ffff:ffff:ffff:ffff
56ffb5:370::/28ffb5:37f:ffff:ffff:ffff:ffff:ffff:ffff
57ffb5:380::/28ffb5:38f:ffff:ffff:ffff:ffff:ffff:ffff
58ffb5:390::/28ffb5:39f:ffff:ffff:ffff:ffff:ffff:ffff
59ffb5:3a0::/28ffb5:3af:ffff:ffff:ffff:ffff:ffff:ffff
60ffb5:3b0::/28ffb5:3bf:ffff:ffff:ffff:ffff:ffff:ffff
61ffb5:3c0::/28ffb5:3cf:ffff:ffff:ffff:ffff:ffff:ffff
62ffb5:3d0::/28ffb5:3df:ffff:ffff:ffff:ffff:ffff:ffff
63ffb5:3e0::/28ffb5:3ef:ffff:ffff:ffff:ffff:ffff:ffff
64ffb5:3f0::/28ffb5:3ff:ffff:ffff:ffff:ffff:ffff:ffff
65ffb5:400::/28ffb5:40f:ffff:ffff:ffff:ffff:ffff:ffff
66ffb5:410::/28ffb5:41f:ffff:ffff:ffff:ffff:ffff:ffff
67ffb5:420::/28ffb5:42f:ffff:ffff:ffff:ffff:ffff:ffff
68ffb5:430::/28ffb5:43f:ffff:ffff:ffff:ffff:ffff:ffff
69ffb5:440::/28ffb5:44f:ffff:ffff:ffff:ffff:ffff:ffff
70ffb5:450::/28ffb5:45f:ffff:ffff:ffff:ffff:ffff:ffff
71ffb5:460::/28ffb5:46f:ffff:ffff:ffff:ffff:ffff:ffff
72ffb5:470::/28ffb5:47f:ffff:ffff:ffff:ffff:ffff:ffff
73ffb5:480::/28ffb5:48f:ffff:ffff:ffff:ffff:ffff:ffff
74ffb5:490::/28ffb5:49f:ffff:ffff:ffff:ffff:ffff:ffff
75ffb5:4a0::/28ffb5:4af:ffff:ffff:ffff:ffff:ffff:ffff
76ffb5:4b0::/28ffb5:4bf:ffff:ffff:ffff:ffff:ffff:ffff
77ffb5:4c0::/28ffb5:4cf:ffff:ffff:ffff:ffff:ffff:ffff
78ffb5:4d0::/28ffb5:4df:ffff:ffff:ffff:ffff:ffff:ffff
79ffb5:4e0::/28ffb5:4ef:ffff:ffff:ffff:ffff:ffff:ffff
80ffb5:4f0::/28ffb5:4ff:ffff:ffff:ffff:ffff:ffff:ffff
81ffb5:500::/28ffb5:50f:ffff:ffff:ffff:ffff:ffff:ffff
82ffb5:510::/28ffb5:51f:ffff:ffff:ffff:ffff:ffff:ffff
83ffb5:520::/28ffb5:52f:ffff:ffff:ffff:ffff:ffff:ffff
84ffb5:530::/28ffb5:53f:ffff:ffff:ffff:ffff:ffff:ffff
85ffb5:540::/28ffb5:54f:ffff:ffff:ffff:ffff:ffff:ffff
86ffb5:550::/28ffb5:55f:ffff:ffff:ffff:ffff:ffff:ffff
87ffb5:560::/28ffb5:56f:ffff:ffff:ffff:ffff:ffff:ffff
88ffb5:570::/28ffb5:57f:ffff:ffff:ffff:ffff:ffff:ffff
89ffb5:580::/28ffb5:58f:ffff:ffff:ffff:ffff:ffff:ffff
90ffb5:590::/28ffb5:59f:ffff:ffff:ffff:ffff:ffff:ffff
91ffb5:5a0::/28ffb5:5af:ffff:ffff:ffff:ffff:ffff:ffff
92ffb5:5b0::/28ffb5:5bf:ffff:ffff:ffff:ffff:ffff:ffff
93ffb5:5c0::/28ffb5:5cf:ffff:ffff:ffff:ffff:ffff:ffff
94ffb5:5d0::/28ffb5:5df:ffff:ffff:ffff:ffff:ffff:ffff
95ffb5:5e0::/28ffb5:5ef:ffff:ffff:ffff:ffff:ffff:ffff
96ffb5:5f0::/28ffb5:5ff:ffff:ffff:ffff:ffff:ffff:ffff
97ffb5:600::/28ffb5:60f:ffff:ffff:ffff:ffff:ffff:ffff
98ffb5:610::/28ffb5:61f:ffff:ffff:ffff:ffff:ffff:ffff
99ffb5:620::/28ffb5:62f:ffff:ffff:ffff:ffff:ffff:ffff
100ffb5:630::/28ffb5:63f:ffff:ffff:ffff:ffff:ffff:ffff
101ffb5:640::/28ffb5:64f:ffff:ffff:ffff:ffff:ffff:ffff
102ffb5:650::/28ffb5:65f:ffff:ffff:ffff:ffff:ffff:ffff
103ffb5:660::/28ffb5:66f:ffff:ffff:ffff:ffff:ffff:ffff
104ffb5:670::/28ffb5:67f:ffff:ffff:ffff:ffff:ffff:ffff
105ffb5:680::/28ffb5:68f:ffff:ffff:ffff:ffff:ffff:ffff
106ffb5:690::/28ffb5:69f:ffff:ffff:ffff:ffff:ffff:ffff
107ffb5:6a0::/28ffb5:6af:ffff:ffff:ffff:ffff:ffff:ffff
108ffb5:6b0::/28ffb5:6bf:ffff:ffff:ffff:ffff:ffff:ffff
109ffb5:6c0::/28ffb5:6cf:ffff:ffff:ffff:ffff:ffff:ffff
110ffb5:6d0::/28ffb5:6df:ffff:ffff:ffff:ffff:ffff:ffff
111ffb5:6e0::/28ffb5:6ef:ffff:ffff:ffff:ffff:ffff:ffff
112ffb5:6f0::/28ffb5:6ff:ffff:ffff:ffff:ffff:ffff:ffff
113ffb5:700::/28ffb5:70f:ffff:ffff:ffff:ffff:ffff:ffff
114ffb5:710::/28ffb5:71f:ffff:ffff:ffff:ffff:ffff:ffff
115ffb5:720::/28ffb5:72f:ffff:ffff:ffff:ffff:ffff:ffff
116ffb5:730::/28ffb5:73f:ffff:ffff:ffff:ffff:ffff:ffff
117ffb5:740::/28ffb5:74f:ffff:ffff:ffff:ffff:ffff:ffff
118ffb5:750::/28ffb5:75f:ffff:ffff:ffff:ffff:ffff:ffff
119ffb5:760::/28ffb5:76f:ffff:ffff:ffff:ffff:ffff:ffff
120ffb5:770::/28ffb5:77f:ffff:ffff:ffff:ffff:ffff:ffff
121ffb5:780::/28ffb5:78f:ffff:ffff:ffff:ffff:ffff:ffff
122ffb5:790::/28ffb5:79f:ffff:ffff:ffff:ffff:ffff:ffff
123ffb5:7a0::/28ffb5:7af:ffff:ffff:ffff:ffff:ffff:ffff
124ffb5:7b0::/28ffb5:7bf:ffff:ffff:ffff:ffff:ffff:ffff
125ffb5:7c0::/28ffb5:7cf:ffff:ffff:ffff:ffff:ffff:ffff
126ffb5:7d0::/28ffb5:7df:ffff:ffff:ffff:ffff:ffff:ffff
127ffb5:7e0::/28ffb5:7ef:ffff:ffff:ffff:ffff:ffff:ffff
128ffb5:7f0::/28ffb5:7ff:ffff:ffff:ffff:ffff:ffff:ffff
129ffb5:800::/28ffb5:80f:ffff:ffff:ffff:ffff:ffff:ffff
130ffb5:810::/28ffb5:81f:ffff:ffff:ffff:ffff:ffff:ffff
131ffb5:820::/28ffb5:82f:ffff:ffff:ffff:ffff:ffff:ffff
132ffb5:830::/28ffb5:83f:ffff:ffff:ffff:ffff:ffff:ffff
133ffb5:840::/28ffb5:84f:ffff:ffff:ffff:ffff:ffff:ffff
134ffb5:850::/28ffb5:85f:ffff:ffff:ffff:ffff:ffff:ffff
135ffb5:860::/28ffb5:86f:ffff:ffff:ffff:ffff:ffff:ffff
136ffb5:870::/28ffb5:87f:ffff:ffff:ffff:ffff:ffff:ffff
137ffb5:880::/28ffb5:88f:ffff:ffff:ffff:ffff:ffff:ffff
138ffb5:890::/28ffb5:89f:ffff:ffff:ffff:ffff:ffff:ffff
139ffb5:8a0::/28ffb5:8af:ffff:ffff:ffff:ffff:ffff:ffff
140ffb5:8b0::/28ffb5:8bf:ffff:ffff:ffff:ffff:ffff:ffff
141ffb5:8c0::/28ffb5:8cf:ffff:ffff:ffff:ffff:ffff:ffff
142ffb5:8d0::/28ffb5:8df:ffff:ffff:ffff:ffff:ffff:ffff
143ffb5:8e0::/28ffb5:8ef:ffff:ffff:ffff:ffff:ffff:ffff
144ffb5:8f0::/28ffb5:8ff:ffff:ffff:ffff:ffff:ffff:ffff
145ffb5:900::/28ffb5:90f:ffff:ffff:ffff:ffff:ffff:ffff
146ffb5:910::/28ffb5:91f:ffff:ffff:ffff:ffff:ffff:ffff
147ffb5:920::/28ffb5:92f:ffff:ffff:ffff:ffff:ffff:ffff
148ffb5:930::/28ffb5:93f:ffff:ffff:ffff:ffff:ffff:ffff
149ffb5:940::/28ffb5:94f:ffff:ffff:ffff:ffff:ffff:ffff
150ffb5:950::/28ffb5:95f:ffff:ffff:ffff:ffff:ffff:ffff
151ffb5:960::/28ffb5:96f:ffff:ffff:ffff:ffff:ffff:ffff
152ffb5:970::/28ffb5:97f:ffff:ffff:ffff:ffff:ffff:ffff
153ffb5:980::/28ffb5:98f:ffff:ffff:ffff:ffff:ffff:ffff
154ffb5:990::/28ffb5:99f:ffff:ffff:ffff:ffff:ffff:ffff
155ffb5:9a0::/28ffb5:9af:ffff:ffff:ffff:ffff:ffff:ffff
156ffb5:9b0::/28ffb5:9bf:ffff:ffff:ffff:ffff:ffff:ffff
157ffb5:9c0::/28ffb5:9cf:ffff:ffff:ffff:ffff:ffff:ffff
158ffb5:9d0::/28ffb5:9df:ffff:ffff:ffff:ffff:ffff:ffff
159ffb5:9e0::/28ffb5:9ef:ffff:ffff:ffff:ffff:ffff:ffff
160ffb5:9f0::/28ffb5:9ff:ffff:ffff:ffff:ffff:ffff:ffff
161ffb5:a00::/28ffb5:a0f:ffff:ffff:ffff:ffff:ffff:ffff
162ffb5:a10::/28ffb5:a1f:ffff:ffff:ffff:ffff:ffff:ffff
163ffb5:a20::/28ffb5:a2f:ffff:ffff:ffff:ffff:ffff:ffff
164ffb5:a30::/28ffb5:a3f:ffff:ffff:ffff:ffff:ffff:ffff
165ffb5:a40::/28ffb5:a4f:ffff:ffff:ffff:ffff:ffff:ffff
166ffb5:a50::/28ffb5:a5f:ffff:ffff:ffff:ffff:ffff:ffff
167ffb5:a60::/28ffb5:a6f:ffff:ffff:ffff:ffff:ffff:ffff
168ffb5:a70::/28ffb5:a7f:ffff:ffff:ffff:ffff:ffff:ffff
169ffb5:a80::/28ffb5:a8f:ffff:ffff:ffff:ffff:ffff:ffff
170ffb5:a90::/28ffb5:a9f:ffff:ffff:ffff:ffff:ffff:ffff
171ffb5:aa0::/28ffb5:aaf:ffff:ffff:ffff:ffff:ffff:ffff
172ffb5:ab0::/28ffb5:abf:ffff:ffff:ffff:ffff:ffff:ffff
173ffb5:ac0::/28ffb5:acf:ffff:ffff:ffff:ffff:ffff:ffff
174ffb5:ad0::/28ffb5:adf:ffff:ffff:ffff:ffff:ffff:ffff
175ffb5:ae0::/28ffb5:aef:ffff:ffff:ffff:ffff:ffff:ffff
176ffb5:af0::/28ffb5:aff:ffff:ffff:ffff:ffff:ffff:ffff
177ffb5:b00::/28ffb5:b0f:ffff:ffff:ffff:ffff:ffff:ffff
178ffb5:b10::/28ffb5:b1f:ffff:ffff:ffff:ffff:ffff:ffff
179ffb5:b20::/28ffb5:b2f:ffff:ffff:ffff:ffff:ffff:ffff
180ffb5:b30::/28ffb5:b3f:ffff:ffff:ffff:ffff:ffff:ffff
181ffb5:b40::/28ffb5:b4f:ffff:ffff:ffff:ffff:ffff:ffff
182ffb5:b50::/28ffb5:b5f:ffff:ffff:ffff:ffff:ffff:ffff
183ffb5:b60::/28ffb5:b6f:ffff:ffff:ffff:ffff:ffff:ffff
184ffb5:b70::/28ffb5:b7f:ffff:ffff:ffff:ffff:ffff:ffff
185ffb5:b80::/28ffb5:b8f:ffff:ffff:ffff:ffff:ffff:ffff
186ffb5:b90::/28ffb5:b9f:ffff:ffff:ffff:ffff:ffff:ffff
187ffb5:ba0::/28ffb5:baf:ffff:ffff:ffff:ffff:ffff:ffff
188ffb5:bb0::/28ffb5:bbf:ffff:ffff:ffff:ffff:ffff:ffff
189ffb5:bc0::/28ffb5:bcf:ffff:ffff:ffff:ffff:ffff:ffff
190ffb5:bd0::/28ffb5:bdf:ffff:ffff:ffff:ffff:ffff:ffff
191ffb5:be0::/28ffb5:bef:ffff:ffff:ffff:ffff:ffff:ffff
192ffb5:bf0::/28ffb5:bff:ffff:ffff:ffff:ffff:ffff:ffff
193ffb5:c00::/28ffb5:c0f:ffff:ffff:ffff:ffff:ffff:ffff
194ffb5:c10::/28ffb5:c1f:ffff:ffff:ffff:ffff:ffff:ffff
195ffb5:c20::/28ffb5:c2f:ffff:ffff:ffff:ffff:ffff:ffff
196ffb5:c30::/28ffb5:c3f:ffff:ffff:ffff:ffff:ffff:ffff
197ffb5:c40::/28ffb5:c4f:ffff:ffff:ffff:ffff:ffff:ffff
198ffb5:c50::/28ffb5:c5f:ffff:ffff:ffff:ffff:ffff:ffff
199ffb5:c60::/28ffb5:c6f:ffff:ffff:ffff:ffff:ffff:ffff
200ffb5:c70::/28ffb5:c7f:ffff:ffff:ffff:ffff:ffff:ffff
201ffb5:c80::/28ffb5:c8f:ffff:ffff:ffff:ffff:ffff:ffff
202ffb5:c90::/28ffb5:c9f:ffff:ffff:ffff:ffff:ffff:ffff
203ffb5:ca0::/28ffb5:caf:ffff:ffff:ffff:ffff:ffff:ffff
204ffb5:cb0::/28ffb5:cbf:ffff:ffff:ffff:ffff:ffff:ffff
205ffb5:cc0::/28ffb5:ccf:ffff:ffff:ffff:ffff:ffff:ffff
206ffb5:cd0::/28ffb5:cdf:ffff:ffff:ffff:ffff:ffff:ffff
207ffb5:ce0::/28ffb5:cef:ffff:ffff:ffff:ffff:ffff:ffff
208ffb5:cf0::/28ffb5:cff:ffff:ffff:ffff:ffff:ffff:ffff
209ffb5:d00::/28ffb5:d0f:ffff:ffff:ffff:ffff:ffff:ffff
210ffb5:d10::/28ffb5:d1f:ffff:ffff:ffff:ffff:ffff:ffff
211ffb5:d20::/28ffb5:d2f:ffff:ffff:ffff:ffff:ffff:ffff
212ffb5:d30::/28ffb5:d3f:ffff:ffff:ffff:ffff:ffff:ffff
213ffb5:d40::/28ffb5:d4f:ffff:ffff:ffff:ffff:ffff:ffff
214ffb5:d50::/28ffb5:d5f:ffff:ffff:ffff:ffff:ffff:ffff
215ffb5:d60::/28ffb5:d6f:ffff:ffff:ffff:ffff:ffff:ffff
216ffb5:d70::/28ffb5:d7f:ffff:ffff:ffff:ffff:ffff:ffff
217ffb5:d80::/28ffb5:d8f:ffff:ffff:ffff:ffff:ffff:ffff
218ffb5:d90::/28ffb5:d9f:ffff:ffff:ffff:ffff:ffff:ffff
219ffb5:da0::/28ffb5:daf:ffff:ffff:ffff:ffff:ffff:ffff
220ffb5:db0::/28ffb5:dbf:ffff:ffff:ffff:ffff:ffff:ffff
221ffb5:dc0::/28ffb5:dcf:ffff:ffff:ffff:ffff:ffff:ffff
222ffb5:dd0::/28ffb5:ddf:ffff:ffff:ffff:ffff:ffff:ffff
223ffb5:de0::/28ffb5:def:ffff:ffff:ffff:ffff:ffff:ffff
224ffb5:df0::/28ffb5:dff:ffff:ffff:ffff:ffff:ffff:ffff
225ffb5:e00::/28ffb5:e0f:ffff:ffff:ffff:ffff:ffff:ffff
226ffb5:e10::/28ffb5:e1f:ffff:ffff:ffff:ffff:ffff:ffff
227ffb5:e20::/28ffb5:e2f:ffff:ffff:ffff:ffff:ffff:ffff
228ffb5:e30::/28ffb5:e3f:ffff:ffff:ffff:ffff:ffff:ffff
229ffb5:e40::/28ffb5:e4f:ffff:ffff:ffff:ffff:ffff:ffff
230ffb5:e50::/28ffb5:e5f:ffff:ffff:ffff:ffff:ffff:ffff
231ffb5:e60::/28ffb5:e6f:ffff:ffff:ffff:ffff:ffff:ffff
232ffb5:e70::/28ffb5:e7f:ffff:ffff:ffff:ffff:ffff:ffff
233ffb5:e80::/28ffb5:e8f:ffff:ffff:ffff:ffff:ffff:ffff
234ffb5:e90::/28ffb5:e9f:ffff:ffff:ffff:ffff:ffff:ffff
235ffb5:ea0::/28ffb5:eaf:ffff:ffff:ffff:ffff:ffff:ffff
236ffb5:eb0::/28ffb5:ebf:ffff:ffff:ffff:ffff:ffff:ffff
237ffb5:ec0::/28ffb5:ecf:ffff:ffff:ffff:ffff:ffff:ffff
238ffb5:ed0::/28ffb5:edf:ffff:ffff:ffff:ffff:ffff:ffff
239ffb5:ee0::/28ffb5:eef:ffff:ffff:ffff:ffff:ffff:ffff
240ffb5:ef0::/28ffb5:eff:ffff:ffff:ffff:ffff:ffff:ffff
241ffb5:f00::/28ffb5:f0f:ffff:ffff:ffff:ffff:ffff:ffff
242ffb5:f10::/28ffb5:f1f:ffff:ffff:ffff:ffff:ffff:ffff
243ffb5:f20::/28ffb5:f2f:ffff:ffff:ffff:ffff:ffff:ffff
244ffb5:f30::/28ffb5:f3f:ffff:ffff:ffff:ffff:ffff:ffff
245ffb5:f40::/28ffb5:f4f:ffff:ffff:ffff:ffff:ffff:ffff
246ffb5:f50::/28ffb5:f5f:ffff:ffff:ffff:ffff:ffff:ffff
247ffb5:f60::/28ffb5:f6f:ffff:ffff:ffff:ffff:ffff:ffff
248ffb5:f70::/28ffb5:f7f:ffff:ffff:ffff:ffff:ffff:ffff
249ffb5:f80::/28ffb5:f8f:ffff:ffff:ffff:ffff:ffff:ffff
250ffb5:f90::/28ffb5:f9f:ffff:ffff:ffff:ffff:ffff:ffff
251ffb5:fa0::/28ffb5:faf:ffff:ffff:ffff:ffff:ffff:ffff
252ffb5:fb0::/28ffb5:fbf:ffff:ffff:ffff:ffff:ffff:ffff
253ffb5:fc0::/28ffb5:fcf:ffff:ffff:ffff:ffff:ffff:ffff
254ffb5:fd0::/28ffb5:fdf:ffff:ffff:ffff:ffff:ffff:ffff
255ffb5:fe0::/28ffb5:fef:ffff:ffff:ffff:ffff:ffff:ffff
256ffb5:ff0::/28ffb5: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.