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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
ffc5::/16
First address
ffc5::
Last address
ffc5: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
ffc5:0000:0000:0000:0000:0000:0000:0000
Type
Multicast ff00::/8
One-to-many traffic; replaces broadcast
Reverse DNS zone
5.c.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)

ffc5::/16 makes 4,096 subnets of /28; the first 256 are listed.

Subnets
#SubnetLast address
1ffc5::/28ffc5:f:ffff:ffff:ffff:ffff:ffff:ffff
2ffc5:10::/28ffc5:1f:ffff:ffff:ffff:ffff:ffff:ffff
3ffc5:20::/28ffc5:2f:ffff:ffff:ffff:ffff:ffff:ffff
4ffc5:30::/28ffc5:3f:ffff:ffff:ffff:ffff:ffff:ffff
5ffc5:40::/28ffc5:4f:ffff:ffff:ffff:ffff:ffff:ffff
6ffc5:50::/28ffc5:5f:ffff:ffff:ffff:ffff:ffff:ffff
7ffc5:60::/28ffc5:6f:ffff:ffff:ffff:ffff:ffff:ffff
8ffc5:70::/28ffc5:7f:ffff:ffff:ffff:ffff:ffff:ffff
9ffc5:80::/28ffc5:8f:ffff:ffff:ffff:ffff:ffff:ffff
10ffc5:90::/28ffc5:9f:ffff:ffff:ffff:ffff:ffff:ffff
11ffc5:a0::/28ffc5:af:ffff:ffff:ffff:ffff:ffff:ffff
12ffc5:b0::/28ffc5:bf:ffff:ffff:ffff:ffff:ffff:ffff
13ffc5:c0::/28ffc5:cf:ffff:ffff:ffff:ffff:ffff:ffff
14ffc5:d0::/28ffc5:df:ffff:ffff:ffff:ffff:ffff:ffff
15ffc5:e0::/28ffc5:ef:ffff:ffff:ffff:ffff:ffff:ffff
16ffc5:f0::/28ffc5:ff:ffff:ffff:ffff:ffff:ffff:ffff
17ffc5:100::/28ffc5:10f:ffff:ffff:ffff:ffff:ffff:ffff
18ffc5:110::/28ffc5:11f:ffff:ffff:ffff:ffff:ffff:ffff
19ffc5:120::/28ffc5:12f:ffff:ffff:ffff:ffff:ffff:ffff
20ffc5:130::/28ffc5:13f:ffff:ffff:ffff:ffff:ffff:ffff
21ffc5:140::/28ffc5:14f:ffff:ffff:ffff:ffff:ffff:ffff
22ffc5:150::/28ffc5:15f:ffff:ffff:ffff:ffff:ffff:ffff
23ffc5:160::/28ffc5:16f:ffff:ffff:ffff:ffff:ffff:ffff
24ffc5:170::/28ffc5:17f:ffff:ffff:ffff:ffff:ffff:ffff
25ffc5:180::/28ffc5:18f:ffff:ffff:ffff:ffff:ffff:ffff
26ffc5:190::/28ffc5:19f:ffff:ffff:ffff:ffff:ffff:ffff
27ffc5:1a0::/28ffc5:1af:ffff:ffff:ffff:ffff:ffff:ffff
28ffc5:1b0::/28ffc5:1bf:ffff:ffff:ffff:ffff:ffff:ffff
29ffc5:1c0::/28ffc5:1cf:ffff:ffff:ffff:ffff:ffff:ffff
30ffc5:1d0::/28ffc5:1df:ffff:ffff:ffff:ffff:ffff:ffff
31ffc5:1e0::/28ffc5:1ef:ffff:ffff:ffff:ffff:ffff:ffff
32ffc5:1f0::/28ffc5:1ff:ffff:ffff:ffff:ffff:ffff:ffff
33ffc5:200::/28ffc5:20f:ffff:ffff:ffff:ffff:ffff:ffff
34ffc5:210::/28ffc5:21f:ffff:ffff:ffff:ffff:ffff:ffff
35ffc5:220::/28ffc5:22f:ffff:ffff:ffff:ffff:ffff:ffff
36ffc5:230::/28ffc5:23f:ffff:ffff:ffff:ffff:ffff:ffff
37ffc5:240::/28ffc5:24f:ffff:ffff:ffff:ffff:ffff:ffff
38ffc5:250::/28ffc5:25f:ffff:ffff:ffff:ffff:ffff:ffff
39ffc5:260::/28ffc5:26f:ffff:ffff:ffff:ffff:ffff:ffff
40ffc5:270::/28ffc5:27f:ffff:ffff:ffff:ffff:ffff:ffff
41ffc5:280::/28ffc5:28f:ffff:ffff:ffff:ffff:ffff:ffff
42ffc5:290::/28ffc5:29f:ffff:ffff:ffff:ffff:ffff:ffff
43ffc5:2a0::/28ffc5:2af:ffff:ffff:ffff:ffff:ffff:ffff
44ffc5:2b0::/28ffc5:2bf:ffff:ffff:ffff:ffff:ffff:ffff
45ffc5:2c0::/28ffc5:2cf:ffff:ffff:ffff:ffff:ffff:ffff
46ffc5:2d0::/28ffc5:2df:ffff:ffff:ffff:ffff:ffff:ffff
47ffc5:2e0::/28ffc5:2ef:ffff:ffff:ffff:ffff:ffff:ffff
48ffc5:2f0::/28ffc5:2ff:ffff:ffff:ffff:ffff:ffff:ffff
49ffc5:300::/28ffc5:30f:ffff:ffff:ffff:ffff:ffff:ffff
50ffc5:310::/28ffc5:31f:ffff:ffff:ffff:ffff:ffff:ffff
51ffc5:320::/28ffc5:32f:ffff:ffff:ffff:ffff:ffff:ffff
52ffc5:330::/28ffc5:33f:ffff:ffff:ffff:ffff:ffff:ffff
53ffc5:340::/28ffc5:34f:ffff:ffff:ffff:ffff:ffff:ffff
54ffc5:350::/28ffc5:35f:ffff:ffff:ffff:ffff:ffff:ffff
55ffc5:360::/28ffc5:36f:ffff:ffff:ffff:ffff:ffff:ffff
56ffc5:370::/28ffc5:37f:ffff:ffff:ffff:ffff:ffff:ffff
57ffc5:380::/28ffc5:38f:ffff:ffff:ffff:ffff:ffff:ffff
58ffc5:390::/28ffc5:39f:ffff:ffff:ffff:ffff:ffff:ffff
59ffc5:3a0::/28ffc5:3af:ffff:ffff:ffff:ffff:ffff:ffff
60ffc5:3b0::/28ffc5:3bf:ffff:ffff:ffff:ffff:ffff:ffff
61ffc5:3c0::/28ffc5:3cf:ffff:ffff:ffff:ffff:ffff:ffff
62ffc5:3d0::/28ffc5:3df:ffff:ffff:ffff:ffff:ffff:ffff
63ffc5:3e0::/28ffc5:3ef:ffff:ffff:ffff:ffff:ffff:ffff
64ffc5:3f0::/28ffc5:3ff:ffff:ffff:ffff:ffff:ffff:ffff
65ffc5:400::/28ffc5:40f:ffff:ffff:ffff:ffff:ffff:ffff
66ffc5:410::/28ffc5:41f:ffff:ffff:ffff:ffff:ffff:ffff
67ffc5:420::/28ffc5:42f:ffff:ffff:ffff:ffff:ffff:ffff
68ffc5:430::/28ffc5:43f:ffff:ffff:ffff:ffff:ffff:ffff
69ffc5:440::/28ffc5:44f:ffff:ffff:ffff:ffff:ffff:ffff
70ffc5:450::/28ffc5:45f:ffff:ffff:ffff:ffff:ffff:ffff
71ffc5:460::/28ffc5:46f:ffff:ffff:ffff:ffff:ffff:ffff
72ffc5:470::/28ffc5:47f:ffff:ffff:ffff:ffff:ffff:ffff
73ffc5:480::/28ffc5:48f:ffff:ffff:ffff:ffff:ffff:ffff
74ffc5:490::/28ffc5:49f:ffff:ffff:ffff:ffff:ffff:ffff
75ffc5:4a0::/28ffc5:4af:ffff:ffff:ffff:ffff:ffff:ffff
76ffc5:4b0::/28ffc5:4bf:ffff:ffff:ffff:ffff:ffff:ffff
77ffc5:4c0::/28ffc5:4cf:ffff:ffff:ffff:ffff:ffff:ffff
78ffc5:4d0::/28ffc5:4df:ffff:ffff:ffff:ffff:ffff:ffff
79ffc5:4e0::/28ffc5:4ef:ffff:ffff:ffff:ffff:ffff:ffff
80ffc5:4f0::/28ffc5:4ff:ffff:ffff:ffff:ffff:ffff:ffff
81ffc5:500::/28ffc5:50f:ffff:ffff:ffff:ffff:ffff:ffff
82ffc5:510::/28ffc5:51f:ffff:ffff:ffff:ffff:ffff:ffff
83ffc5:520::/28ffc5:52f:ffff:ffff:ffff:ffff:ffff:ffff
84ffc5:530::/28ffc5:53f:ffff:ffff:ffff:ffff:ffff:ffff
85ffc5:540::/28ffc5:54f:ffff:ffff:ffff:ffff:ffff:ffff
86ffc5:550::/28ffc5:55f:ffff:ffff:ffff:ffff:ffff:ffff
87ffc5:560::/28ffc5:56f:ffff:ffff:ffff:ffff:ffff:ffff
88ffc5:570::/28ffc5:57f:ffff:ffff:ffff:ffff:ffff:ffff
89ffc5:580::/28ffc5:58f:ffff:ffff:ffff:ffff:ffff:ffff
90ffc5:590::/28ffc5:59f:ffff:ffff:ffff:ffff:ffff:ffff
91ffc5:5a0::/28ffc5:5af:ffff:ffff:ffff:ffff:ffff:ffff
92ffc5:5b0::/28ffc5:5bf:ffff:ffff:ffff:ffff:ffff:ffff
93ffc5:5c0::/28ffc5:5cf:ffff:ffff:ffff:ffff:ffff:ffff
94ffc5:5d0::/28ffc5:5df:ffff:ffff:ffff:ffff:ffff:ffff
95ffc5:5e0::/28ffc5:5ef:ffff:ffff:ffff:ffff:ffff:ffff
96ffc5:5f0::/28ffc5:5ff:ffff:ffff:ffff:ffff:ffff:ffff
97ffc5:600::/28ffc5:60f:ffff:ffff:ffff:ffff:ffff:ffff
98ffc5:610::/28ffc5:61f:ffff:ffff:ffff:ffff:ffff:ffff
99ffc5:620::/28ffc5:62f:ffff:ffff:ffff:ffff:ffff:ffff
100ffc5:630::/28ffc5:63f:ffff:ffff:ffff:ffff:ffff:ffff
101ffc5:640::/28ffc5:64f:ffff:ffff:ffff:ffff:ffff:ffff
102ffc5:650::/28ffc5:65f:ffff:ffff:ffff:ffff:ffff:ffff
103ffc5:660::/28ffc5:66f:ffff:ffff:ffff:ffff:ffff:ffff
104ffc5:670::/28ffc5:67f:ffff:ffff:ffff:ffff:ffff:ffff
105ffc5:680::/28ffc5:68f:ffff:ffff:ffff:ffff:ffff:ffff
106ffc5:690::/28ffc5:69f:ffff:ffff:ffff:ffff:ffff:ffff
107ffc5:6a0::/28ffc5:6af:ffff:ffff:ffff:ffff:ffff:ffff
108ffc5:6b0::/28ffc5:6bf:ffff:ffff:ffff:ffff:ffff:ffff
109ffc5:6c0::/28ffc5:6cf:ffff:ffff:ffff:ffff:ffff:ffff
110ffc5:6d0::/28ffc5:6df:ffff:ffff:ffff:ffff:ffff:ffff
111ffc5:6e0::/28ffc5:6ef:ffff:ffff:ffff:ffff:ffff:ffff
112ffc5:6f0::/28ffc5:6ff:ffff:ffff:ffff:ffff:ffff:ffff
113ffc5:700::/28ffc5:70f:ffff:ffff:ffff:ffff:ffff:ffff
114ffc5:710::/28ffc5:71f:ffff:ffff:ffff:ffff:ffff:ffff
115ffc5:720::/28ffc5:72f:ffff:ffff:ffff:ffff:ffff:ffff
116ffc5:730::/28ffc5:73f:ffff:ffff:ffff:ffff:ffff:ffff
117ffc5:740::/28ffc5:74f:ffff:ffff:ffff:ffff:ffff:ffff
118ffc5:750::/28ffc5:75f:ffff:ffff:ffff:ffff:ffff:ffff
119ffc5:760::/28ffc5:76f:ffff:ffff:ffff:ffff:ffff:ffff
120ffc5:770::/28ffc5:77f:ffff:ffff:ffff:ffff:ffff:ffff
121ffc5:780::/28ffc5:78f:ffff:ffff:ffff:ffff:ffff:ffff
122ffc5:790::/28ffc5:79f:ffff:ffff:ffff:ffff:ffff:ffff
123ffc5:7a0::/28ffc5:7af:ffff:ffff:ffff:ffff:ffff:ffff
124ffc5:7b0::/28ffc5:7bf:ffff:ffff:ffff:ffff:ffff:ffff
125ffc5:7c0::/28ffc5:7cf:ffff:ffff:ffff:ffff:ffff:ffff
126ffc5:7d0::/28ffc5:7df:ffff:ffff:ffff:ffff:ffff:ffff
127ffc5:7e0::/28ffc5:7ef:ffff:ffff:ffff:ffff:ffff:ffff
128ffc5:7f0::/28ffc5:7ff:ffff:ffff:ffff:ffff:ffff:ffff
129ffc5:800::/28ffc5:80f:ffff:ffff:ffff:ffff:ffff:ffff
130ffc5:810::/28ffc5:81f:ffff:ffff:ffff:ffff:ffff:ffff
131ffc5:820::/28ffc5:82f:ffff:ffff:ffff:ffff:ffff:ffff
132ffc5:830::/28ffc5:83f:ffff:ffff:ffff:ffff:ffff:ffff
133ffc5:840::/28ffc5:84f:ffff:ffff:ffff:ffff:ffff:ffff
134ffc5:850::/28ffc5:85f:ffff:ffff:ffff:ffff:ffff:ffff
135ffc5:860::/28ffc5:86f:ffff:ffff:ffff:ffff:ffff:ffff
136ffc5:870::/28ffc5:87f:ffff:ffff:ffff:ffff:ffff:ffff
137ffc5:880::/28ffc5:88f:ffff:ffff:ffff:ffff:ffff:ffff
138ffc5:890::/28ffc5:89f:ffff:ffff:ffff:ffff:ffff:ffff
139ffc5:8a0::/28ffc5:8af:ffff:ffff:ffff:ffff:ffff:ffff
140ffc5:8b0::/28ffc5:8bf:ffff:ffff:ffff:ffff:ffff:ffff
141ffc5:8c0::/28ffc5:8cf:ffff:ffff:ffff:ffff:ffff:ffff
142ffc5:8d0::/28ffc5:8df:ffff:ffff:ffff:ffff:ffff:ffff
143ffc5:8e0::/28ffc5:8ef:ffff:ffff:ffff:ffff:ffff:ffff
144ffc5:8f0::/28ffc5:8ff:ffff:ffff:ffff:ffff:ffff:ffff
145ffc5:900::/28ffc5:90f:ffff:ffff:ffff:ffff:ffff:ffff
146ffc5:910::/28ffc5:91f:ffff:ffff:ffff:ffff:ffff:ffff
147ffc5:920::/28ffc5:92f:ffff:ffff:ffff:ffff:ffff:ffff
148ffc5:930::/28ffc5:93f:ffff:ffff:ffff:ffff:ffff:ffff
149ffc5:940::/28ffc5:94f:ffff:ffff:ffff:ffff:ffff:ffff
150ffc5:950::/28ffc5:95f:ffff:ffff:ffff:ffff:ffff:ffff
151ffc5:960::/28ffc5:96f:ffff:ffff:ffff:ffff:ffff:ffff
152ffc5:970::/28ffc5:97f:ffff:ffff:ffff:ffff:ffff:ffff
153ffc5:980::/28ffc5:98f:ffff:ffff:ffff:ffff:ffff:ffff
154ffc5:990::/28ffc5:99f:ffff:ffff:ffff:ffff:ffff:ffff
155ffc5:9a0::/28ffc5:9af:ffff:ffff:ffff:ffff:ffff:ffff
156ffc5:9b0::/28ffc5:9bf:ffff:ffff:ffff:ffff:ffff:ffff
157ffc5:9c0::/28ffc5:9cf:ffff:ffff:ffff:ffff:ffff:ffff
158ffc5:9d0::/28ffc5:9df:ffff:ffff:ffff:ffff:ffff:ffff
159ffc5:9e0::/28ffc5:9ef:ffff:ffff:ffff:ffff:ffff:ffff
160ffc5:9f0::/28ffc5:9ff:ffff:ffff:ffff:ffff:ffff:ffff
161ffc5:a00::/28ffc5:a0f:ffff:ffff:ffff:ffff:ffff:ffff
162ffc5:a10::/28ffc5:a1f:ffff:ffff:ffff:ffff:ffff:ffff
163ffc5:a20::/28ffc5:a2f:ffff:ffff:ffff:ffff:ffff:ffff
164ffc5:a30::/28ffc5:a3f:ffff:ffff:ffff:ffff:ffff:ffff
165ffc5:a40::/28ffc5:a4f:ffff:ffff:ffff:ffff:ffff:ffff
166ffc5:a50::/28ffc5:a5f:ffff:ffff:ffff:ffff:ffff:ffff
167ffc5:a60::/28ffc5:a6f:ffff:ffff:ffff:ffff:ffff:ffff
168ffc5:a70::/28ffc5:a7f:ffff:ffff:ffff:ffff:ffff:ffff
169ffc5:a80::/28ffc5:a8f:ffff:ffff:ffff:ffff:ffff:ffff
170ffc5:a90::/28ffc5:a9f:ffff:ffff:ffff:ffff:ffff:ffff
171ffc5:aa0::/28ffc5:aaf:ffff:ffff:ffff:ffff:ffff:ffff
172ffc5:ab0::/28ffc5:abf:ffff:ffff:ffff:ffff:ffff:ffff
173ffc5:ac0::/28ffc5:acf:ffff:ffff:ffff:ffff:ffff:ffff
174ffc5:ad0::/28ffc5:adf:ffff:ffff:ffff:ffff:ffff:ffff
175ffc5:ae0::/28ffc5:aef:ffff:ffff:ffff:ffff:ffff:ffff
176ffc5:af0::/28ffc5:aff:ffff:ffff:ffff:ffff:ffff:ffff
177ffc5:b00::/28ffc5:b0f:ffff:ffff:ffff:ffff:ffff:ffff
178ffc5:b10::/28ffc5:b1f:ffff:ffff:ffff:ffff:ffff:ffff
179ffc5:b20::/28ffc5:b2f:ffff:ffff:ffff:ffff:ffff:ffff
180ffc5:b30::/28ffc5:b3f:ffff:ffff:ffff:ffff:ffff:ffff
181ffc5:b40::/28ffc5:b4f:ffff:ffff:ffff:ffff:ffff:ffff
182ffc5:b50::/28ffc5:b5f:ffff:ffff:ffff:ffff:ffff:ffff
183ffc5:b60::/28ffc5:b6f:ffff:ffff:ffff:ffff:ffff:ffff
184ffc5:b70::/28ffc5:b7f:ffff:ffff:ffff:ffff:ffff:ffff
185ffc5:b80::/28ffc5:b8f:ffff:ffff:ffff:ffff:ffff:ffff
186ffc5:b90::/28ffc5:b9f:ffff:ffff:ffff:ffff:ffff:ffff
187ffc5:ba0::/28ffc5:baf:ffff:ffff:ffff:ffff:ffff:ffff
188ffc5:bb0::/28ffc5:bbf:ffff:ffff:ffff:ffff:ffff:ffff
189ffc5:bc0::/28ffc5:bcf:ffff:ffff:ffff:ffff:ffff:ffff
190ffc5:bd0::/28ffc5:bdf:ffff:ffff:ffff:ffff:ffff:ffff
191ffc5:be0::/28ffc5:bef:ffff:ffff:ffff:ffff:ffff:ffff
192ffc5:bf0::/28ffc5:bff:ffff:ffff:ffff:ffff:ffff:ffff
193ffc5:c00::/28ffc5:c0f:ffff:ffff:ffff:ffff:ffff:ffff
194ffc5:c10::/28ffc5:c1f:ffff:ffff:ffff:ffff:ffff:ffff
195ffc5:c20::/28ffc5:c2f:ffff:ffff:ffff:ffff:ffff:ffff
196ffc5:c30::/28ffc5:c3f:ffff:ffff:ffff:ffff:ffff:ffff
197ffc5:c40::/28ffc5:c4f:ffff:ffff:ffff:ffff:ffff:ffff
198ffc5:c50::/28ffc5:c5f:ffff:ffff:ffff:ffff:ffff:ffff
199ffc5:c60::/28ffc5:c6f:ffff:ffff:ffff:ffff:ffff:ffff
200ffc5:c70::/28ffc5:c7f:ffff:ffff:ffff:ffff:ffff:ffff
201ffc5:c80::/28ffc5:c8f:ffff:ffff:ffff:ffff:ffff:ffff
202ffc5:c90::/28ffc5:c9f:ffff:ffff:ffff:ffff:ffff:ffff
203ffc5:ca0::/28ffc5:caf:ffff:ffff:ffff:ffff:ffff:ffff
204ffc5:cb0::/28ffc5:cbf:ffff:ffff:ffff:ffff:ffff:ffff
205ffc5:cc0::/28ffc5:ccf:ffff:ffff:ffff:ffff:ffff:ffff
206ffc5:cd0::/28ffc5:cdf:ffff:ffff:ffff:ffff:ffff:ffff
207ffc5:ce0::/28ffc5:cef:ffff:ffff:ffff:ffff:ffff:ffff
208ffc5:cf0::/28ffc5:cff:ffff:ffff:ffff:ffff:ffff:ffff
209ffc5:d00::/28ffc5:d0f:ffff:ffff:ffff:ffff:ffff:ffff
210ffc5:d10::/28ffc5:d1f:ffff:ffff:ffff:ffff:ffff:ffff
211ffc5:d20::/28ffc5:d2f:ffff:ffff:ffff:ffff:ffff:ffff
212ffc5:d30::/28ffc5:d3f:ffff:ffff:ffff:ffff:ffff:ffff
213ffc5:d40::/28ffc5:d4f:ffff:ffff:ffff:ffff:ffff:ffff
214ffc5:d50::/28ffc5:d5f:ffff:ffff:ffff:ffff:ffff:ffff
215ffc5:d60::/28ffc5:d6f:ffff:ffff:ffff:ffff:ffff:ffff
216ffc5:d70::/28ffc5:d7f:ffff:ffff:ffff:ffff:ffff:ffff
217ffc5:d80::/28ffc5:d8f:ffff:ffff:ffff:ffff:ffff:ffff
218ffc5:d90::/28ffc5:d9f:ffff:ffff:ffff:ffff:ffff:ffff
219ffc5:da0::/28ffc5:daf:ffff:ffff:ffff:ffff:ffff:ffff
220ffc5:db0::/28ffc5:dbf:ffff:ffff:ffff:ffff:ffff:ffff
221ffc5:dc0::/28ffc5:dcf:ffff:ffff:ffff:ffff:ffff:ffff
222ffc5:dd0::/28ffc5:ddf:ffff:ffff:ffff:ffff:ffff:ffff
223ffc5:de0::/28ffc5:def:ffff:ffff:ffff:ffff:ffff:ffff
224ffc5:df0::/28ffc5:dff:ffff:ffff:ffff:ffff:ffff:ffff
225ffc5:e00::/28ffc5:e0f:ffff:ffff:ffff:ffff:ffff:ffff
226ffc5:e10::/28ffc5:e1f:ffff:ffff:ffff:ffff:ffff:ffff
227ffc5:e20::/28ffc5:e2f:ffff:ffff:ffff:ffff:ffff:ffff
228ffc5:e30::/28ffc5:e3f:ffff:ffff:ffff:ffff:ffff:ffff
229ffc5:e40::/28ffc5:e4f:ffff:ffff:ffff:ffff:ffff:ffff
230ffc5:e50::/28ffc5:e5f:ffff:ffff:ffff:ffff:ffff:ffff
231ffc5:e60::/28ffc5:e6f:ffff:ffff:ffff:ffff:ffff:ffff
232ffc5:e70::/28ffc5:e7f:ffff:ffff:ffff:ffff:ffff:ffff
233ffc5:e80::/28ffc5:e8f:ffff:ffff:ffff:ffff:ffff:ffff
234ffc5:e90::/28ffc5:e9f:ffff:ffff:ffff:ffff:ffff:ffff
235ffc5:ea0::/28ffc5:eaf:ffff:ffff:ffff:ffff:ffff:ffff
236ffc5:eb0::/28ffc5:ebf:ffff:ffff:ffff:ffff:ffff:ffff
237ffc5:ec0::/28ffc5:ecf:ffff:ffff:ffff:ffff:ffff:ffff
238ffc5:ed0::/28ffc5:edf:ffff:ffff:ffff:ffff:ffff:ffff
239ffc5:ee0::/28ffc5:eef:ffff:ffff:ffff:ffff:ffff:ffff
240ffc5:ef0::/28ffc5:eff:ffff:ffff:ffff:ffff:ffff:ffff
241ffc5:f00::/28ffc5:f0f:ffff:ffff:ffff:ffff:ffff:ffff
242ffc5:f10::/28ffc5:f1f:ffff:ffff:ffff:ffff:ffff:ffff
243ffc5:f20::/28ffc5:f2f:ffff:ffff:ffff:ffff:ffff:ffff
244ffc5:f30::/28ffc5:f3f:ffff:ffff:ffff:ffff:ffff:ffff
245ffc5:f40::/28ffc5:f4f:ffff:ffff:ffff:ffff:ffff:ffff
246ffc5:f50::/28ffc5:f5f:ffff:ffff:ffff:ffff:ffff:ffff
247ffc5:f60::/28ffc5:f6f:ffff:ffff:ffff:ffff:ffff:ffff
248ffc5:f70::/28ffc5:f7f:ffff:ffff:ffff:ffff:ffff:ffff
249ffc5:f80::/28ffc5:f8f:ffff:ffff:ffff:ffff:ffff:ffff
250ffc5:f90::/28ffc5:f9f:ffff:ffff:ffff:ffff:ffff:ffff
251ffc5:fa0::/28ffc5:faf:ffff:ffff:ffff:ffff:ffff:ffff
252ffc5:fb0::/28ffc5:fbf:ffff:ffff:ffff:ffff:ffff:ffff
253ffc5:fc0::/28ffc5:fcf:ffff:ffff:ffff:ffff:ffff:ffff
254ffc5:fd0::/28ffc5:fdf:ffff:ffff:ffff:ffff:ffff:ffff
255ffc5:fe0::/28ffc5:fef:ffff:ffff:ffff:ffff:ffff:ffff
256ffc5:ff0::/28ffc5: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.