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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
fcd8::/16
First address
fcd8::
Last address
fcd8: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
fcd8:0000:0000:0000:0000:0000:0000:0000
Type
Unique local (ULA) fc00::/7
Private IPv6, like RFC 1918; usually fd00::/8
Reverse DNS zone
8.d.c.f.ip6.arpa
Split into smaller subnets/28
/17 (2)/18 (4)/19 (8)/20 (16)/24 (256)/28 (4,096)/32 (65,536)

fcd8::/16 makes 4,096 subnets of /28; the first 256 are listed.

Subnets
#SubnetLast address
1fcd8::/28fcd8:f:ffff:ffff:ffff:ffff:ffff:ffff
2fcd8:10::/28fcd8:1f:ffff:ffff:ffff:ffff:ffff:ffff
3fcd8:20::/28fcd8:2f:ffff:ffff:ffff:ffff:ffff:ffff
4fcd8:30::/28fcd8:3f:ffff:ffff:ffff:ffff:ffff:ffff
5fcd8:40::/28fcd8:4f:ffff:ffff:ffff:ffff:ffff:ffff
6fcd8:50::/28fcd8:5f:ffff:ffff:ffff:ffff:ffff:ffff
7fcd8:60::/28fcd8:6f:ffff:ffff:ffff:ffff:ffff:ffff
8fcd8:70::/28fcd8:7f:ffff:ffff:ffff:ffff:ffff:ffff
9fcd8:80::/28fcd8:8f:ffff:ffff:ffff:ffff:ffff:ffff
10fcd8:90::/28fcd8:9f:ffff:ffff:ffff:ffff:ffff:ffff
11fcd8:a0::/28fcd8:af:ffff:ffff:ffff:ffff:ffff:ffff
12fcd8:b0::/28fcd8:bf:ffff:ffff:ffff:ffff:ffff:ffff
13fcd8:c0::/28fcd8:cf:ffff:ffff:ffff:ffff:ffff:ffff
14fcd8:d0::/28fcd8:df:ffff:ffff:ffff:ffff:ffff:ffff
15fcd8:e0::/28fcd8:ef:ffff:ffff:ffff:ffff:ffff:ffff
16fcd8:f0::/28fcd8:ff:ffff:ffff:ffff:ffff:ffff:ffff
17fcd8:100::/28fcd8:10f:ffff:ffff:ffff:ffff:ffff:ffff
18fcd8:110::/28fcd8:11f:ffff:ffff:ffff:ffff:ffff:ffff
19fcd8:120::/28fcd8:12f:ffff:ffff:ffff:ffff:ffff:ffff
20fcd8:130::/28fcd8:13f:ffff:ffff:ffff:ffff:ffff:ffff
21fcd8:140::/28fcd8:14f:ffff:ffff:ffff:ffff:ffff:ffff
22fcd8:150::/28fcd8:15f:ffff:ffff:ffff:ffff:ffff:ffff
23fcd8:160::/28fcd8:16f:ffff:ffff:ffff:ffff:ffff:ffff
24fcd8:170::/28fcd8:17f:ffff:ffff:ffff:ffff:ffff:ffff
25fcd8:180::/28fcd8:18f:ffff:ffff:ffff:ffff:ffff:ffff
26fcd8:190::/28fcd8:19f:ffff:ffff:ffff:ffff:ffff:ffff
27fcd8:1a0::/28fcd8:1af:ffff:ffff:ffff:ffff:ffff:ffff
28fcd8:1b0::/28fcd8:1bf:ffff:ffff:ffff:ffff:ffff:ffff
29fcd8:1c0::/28fcd8:1cf:ffff:ffff:ffff:ffff:ffff:ffff
30fcd8:1d0::/28fcd8:1df:ffff:ffff:ffff:ffff:ffff:ffff
31fcd8:1e0::/28fcd8:1ef:ffff:ffff:ffff:ffff:ffff:ffff
32fcd8:1f0::/28fcd8:1ff:ffff:ffff:ffff:ffff:ffff:ffff
33fcd8:200::/28fcd8:20f:ffff:ffff:ffff:ffff:ffff:ffff
34fcd8:210::/28fcd8:21f:ffff:ffff:ffff:ffff:ffff:ffff
35fcd8:220::/28fcd8:22f:ffff:ffff:ffff:ffff:ffff:ffff
36fcd8:230::/28fcd8:23f:ffff:ffff:ffff:ffff:ffff:ffff
37fcd8:240::/28fcd8:24f:ffff:ffff:ffff:ffff:ffff:ffff
38fcd8:250::/28fcd8:25f:ffff:ffff:ffff:ffff:ffff:ffff
39fcd8:260::/28fcd8:26f:ffff:ffff:ffff:ffff:ffff:ffff
40fcd8:270::/28fcd8:27f:ffff:ffff:ffff:ffff:ffff:ffff
41fcd8:280::/28fcd8:28f:ffff:ffff:ffff:ffff:ffff:ffff
42fcd8:290::/28fcd8:29f:ffff:ffff:ffff:ffff:ffff:ffff
43fcd8:2a0::/28fcd8:2af:ffff:ffff:ffff:ffff:ffff:ffff
44fcd8:2b0::/28fcd8:2bf:ffff:ffff:ffff:ffff:ffff:ffff
45fcd8:2c0::/28fcd8:2cf:ffff:ffff:ffff:ffff:ffff:ffff
46fcd8:2d0::/28fcd8:2df:ffff:ffff:ffff:ffff:ffff:ffff
47fcd8:2e0::/28fcd8:2ef:ffff:ffff:ffff:ffff:ffff:ffff
48fcd8:2f0::/28fcd8:2ff:ffff:ffff:ffff:ffff:ffff:ffff
49fcd8:300::/28fcd8:30f:ffff:ffff:ffff:ffff:ffff:ffff
50fcd8:310::/28fcd8:31f:ffff:ffff:ffff:ffff:ffff:ffff
51fcd8:320::/28fcd8:32f:ffff:ffff:ffff:ffff:ffff:ffff
52fcd8:330::/28fcd8:33f:ffff:ffff:ffff:ffff:ffff:ffff
53fcd8:340::/28fcd8:34f:ffff:ffff:ffff:ffff:ffff:ffff
54fcd8:350::/28fcd8:35f:ffff:ffff:ffff:ffff:ffff:ffff
55fcd8:360::/28fcd8:36f:ffff:ffff:ffff:ffff:ffff:ffff
56fcd8:370::/28fcd8:37f:ffff:ffff:ffff:ffff:ffff:ffff
57fcd8:380::/28fcd8:38f:ffff:ffff:ffff:ffff:ffff:ffff
58fcd8:390::/28fcd8:39f:ffff:ffff:ffff:ffff:ffff:ffff
59fcd8:3a0::/28fcd8:3af:ffff:ffff:ffff:ffff:ffff:ffff
60fcd8:3b0::/28fcd8:3bf:ffff:ffff:ffff:ffff:ffff:ffff
61fcd8:3c0::/28fcd8:3cf:ffff:ffff:ffff:ffff:ffff:ffff
62fcd8:3d0::/28fcd8:3df:ffff:ffff:ffff:ffff:ffff:ffff
63fcd8:3e0::/28fcd8:3ef:ffff:ffff:ffff:ffff:ffff:ffff
64fcd8:3f0::/28fcd8:3ff:ffff:ffff:ffff:ffff:ffff:ffff
65fcd8:400::/28fcd8:40f:ffff:ffff:ffff:ffff:ffff:ffff
66fcd8:410::/28fcd8:41f:ffff:ffff:ffff:ffff:ffff:ffff
67fcd8:420::/28fcd8:42f:ffff:ffff:ffff:ffff:ffff:ffff
68fcd8:430::/28fcd8:43f:ffff:ffff:ffff:ffff:ffff:ffff
69fcd8:440::/28fcd8:44f:ffff:ffff:ffff:ffff:ffff:ffff
70fcd8:450::/28fcd8:45f:ffff:ffff:ffff:ffff:ffff:ffff
71fcd8:460::/28fcd8:46f:ffff:ffff:ffff:ffff:ffff:ffff
72fcd8:470::/28fcd8:47f:ffff:ffff:ffff:ffff:ffff:ffff
73fcd8:480::/28fcd8:48f:ffff:ffff:ffff:ffff:ffff:ffff
74fcd8:490::/28fcd8:49f:ffff:ffff:ffff:ffff:ffff:ffff
75fcd8:4a0::/28fcd8:4af:ffff:ffff:ffff:ffff:ffff:ffff
76fcd8:4b0::/28fcd8:4bf:ffff:ffff:ffff:ffff:ffff:ffff
77fcd8:4c0::/28fcd8:4cf:ffff:ffff:ffff:ffff:ffff:ffff
78fcd8:4d0::/28fcd8:4df:ffff:ffff:ffff:ffff:ffff:ffff
79fcd8:4e0::/28fcd8:4ef:ffff:ffff:ffff:ffff:ffff:ffff
80fcd8:4f0::/28fcd8:4ff:ffff:ffff:ffff:ffff:ffff:ffff
81fcd8:500::/28fcd8:50f:ffff:ffff:ffff:ffff:ffff:ffff
82fcd8:510::/28fcd8:51f:ffff:ffff:ffff:ffff:ffff:ffff
83fcd8:520::/28fcd8:52f:ffff:ffff:ffff:ffff:ffff:ffff
84fcd8:530::/28fcd8:53f:ffff:ffff:ffff:ffff:ffff:ffff
85fcd8:540::/28fcd8:54f:ffff:ffff:ffff:ffff:ffff:ffff
86fcd8:550::/28fcd8:55f:ffff:ffff:ffff:ffff:ffff:ffff
87fcd8:560::/28fcd8:56f:ffff:ffff:ffff:ffff:ffff:ffff
88fcd8:570::/28fcd8:57f:ffff:ffff:ffff:ffff:ffff:ffff
89fcd8:580::/28fcd8:58f:ffff:ffff:ffff:ffff:ffff:ffff
90fcd8:590::/28fcd8:59f:ffff:ffff:ffff:ffff:ffff:ffff
91fcd8:5a0::/28fcd8:5af:ffff:ffff:ffff:ffff:ffff:ffff
92fcd8:5b0::/28fcd8:5bf:ffff:ffff:ffff:ffff:ffff:ffff
93fcd8:5c0::/28fcd8:5cf:ffff:ffff:ffff:ffff:ffff:ffff
94fcd8:5d0::/28fcd8:5df:ffff:ffff:ffff:ffff:ffff:ffff
95fcd8:5e0::/28fcd8:5ef:ffff:ffff:ffff:ffff:ffff:ffff
96fcd8:5f0::/28fcd8:5ff:ffff:ffff:ffff:ffff:ffff:ffff
97fcd8:600::/28fcd8:60f:ffff:ffff:ffff:ffff:ffff:ffff
98fcd8:610::/28fcd8:61f:ffff:ffff:ffff:ffff:ffff:ffff
99fcd8:620::/28fcd8:62f:ffff:ffff:ffff:ffff:ffff:ffff
100fcd8:630::/28fcd8:63f:ffff:ffff:ffff:ffff:ffff:ffff
101fcd8:640::/28fcd8:64f:ffff:ffff:ffff:ffff:ffff:ffff
102fcd8:650::/28fcd8:65f:ffff:ffff:ffff:ffff:ffff:ffff
103fcd8:660::/28fcd8:66f:ffff:ffff:ffff:ffff:ffff:ffff
104fcd8:670::/28fcd8:67f:ffff:ffff:ffff:ffff:ffff:ffff
105fcd8:680::/28fcd8:68f:ffff:ffff:ffff:ffff:ffff:ffff
106fcd8:690::/28fcd8:69f:ffff:ffff:ffff:ffff:ffff:ffff
107fcd8:6a0::/28fcd8:6af:ffff:ffff:ffff:ffff:ffff:ffff
108fcd8:6b0::/28fcd8:6bf:ffff:ffff:ffff:ffff:ffff:ffff
109fcd8:6c0::/28fcd8:6cf:ffff:ffff:ffff:ffff:ffff:ffff
110fcd8:6d0::/28fcd8:6df:ffff:ffff:ffff:ffff:ffff:ffff
111fcd8:6e0::/28fcd8:6ef:ffff:ffff:ffff:ffff:ffff:ffff
112fcd8:6f0::/28fcd8:6ff:ffff:ffff:ffff:ffff:ffff:ffff
113fcd8:700::/28fcd8:70f:ffff:ffff:ffff:ffff:ffff:ffff
114fcd8:710::/28fcd8:71f:ffff:ffff:ffff:ffff:ffff:ffff
115fcd8:720::/28fcd8:72f:ffff:ffff:ffff:ffff:ffff:ffff
116fcd8:730::/28fcd8:73f:ffff:ffff:ffff:ffff:ffff:ffff
117fcd8:740::/28fcd8:74f:ffff:ffff:ffff:ffff:ffff:ffff
118fcd8:750::/28fcd8:75f:ffff:ffff:ffff:ffff:ffff:ffff
119fcd8:760::/28fcd8:76f:ffff:ffff:ffff:ffff:ffff:ffff
120fcd8:770::/28fcd8:77f:ffff:ffff:ffff:ffff:ffff:ffff
121fcd8:780::/28fcd8:78f:ffff:ffff:ffff:ffff:ffff:ffff
122fcd8:790::/28fcd8:79f:ffff:ffff:ffff:ffff:ffff:ffff
123fcd8:7a0::/28fcd8:7af:ffff:ffff:ffff:ffff:ffff:ffff
124fcd8:7b0::/28fcd8:7bf:ffff:ffff:ffff:ffff:ffff:ffff
125fcd8:7c0::/28fcd8:7cf:ffff:ffff:ffff:ffff:ffff:ffff
126fcd8:7d0::/28fcd8:7df:ffff:ffff:ffff:ffff:ffff:ffff
127fcd8:7e0::/28fcd8:7ef:ffff:ffff:ffff:ffff:ffff:ffff
128fcd8:7f0::/28fcd8:7ff:ffff:ffff:ffff:ffff:ffff:ffff
129fcd8:800::/28fcd8:80f:ffff:ffff:ffff:ffff:ffff:ffff
130fcd8:810::/28fcd8:81f:ffff:ffff:ffff:ffff:ffff:ffff
131fcd8:820::/28fcd8:82f:ffff:ffff:ffff:ffff:ffff:ffff
132fcd8:830::/28fcd8:83f:ffff:ffff:ffff:ffff:ffff:ffff
133fcd8:840::/28fcd8:84f:ffff:ffff:ffff:ffff:ffff:ffff
134fcd8:850::/28fcd8:85f:ffff:ffff:ffff:ffff:ffff:ffff
135fcd8:860::/28fcd8:86f:ffff:ffff:ffff:ffff:ffff:ffff
136fcd8:870::/28fcd8:87f:ffff:ffff:ffff:ffff:ffff:ffff
137fcd8:880::/28fcd8:88f:ffff:ffff:ffff:ffff:ffff:ffff
138fcd8:890::/28fcd8:89f:ffff:ffff:ffff:ffff:ffff:ffff
139fcd8:8a0::/28fcd8:8af:ffff:ffff:ffff:ffff:ffff:ffff
140fcd8:8b0::/28fcd8:8bf:ffff:ffff:ffff:ffff:ffff:ffff
141fcd8:8c0::/28fcd8:8cf:ffff:ffff:ffff:ffff:ffff:ffff
142fcd8:8d0::/28fcd8:8df:ffff:ffff:ffff:ffff:ffff:ffff
143fcd8:8e0::/28fcd8:8ef:ffff:ffff:ffff:ffff:ffff:ffff
144fcd8:8f0::/28fcd8:8ff:ffff:ffff:ffff:ffff:ffff:ffff
145fcd8:900::/28fcd8:90f:ffff:ffff:ffff:ffff:ffff:ffff
146fcd8:910::/28fcd8:91f:ffff:ffff:ffff:ffff:ffff:ffff
147fcd8:920::/28fcd8:92f:ffff:ffff:ffff:ffff:ffff:ffff
148fcd8:930::/28fcd8:93f:ffff:ffff:ffff:ffff:ffff:ffff
149fcd8:940::/28fcd8:94f:ffff:ffff:ffff:ffff:ffff:ffff
150fcd8:950::/28fcd8:95f:ffff:ffff:ffff:ffff:ffff:ffff
151fcd8:960::/28fcd8:96f:ffff:ffff:ffff:ffff:ffff:ffff
152fcd8:970::/28fcd8:97f:ffff:ffff:ffff:ffff:ffff:ffff
153fcd8:980::/28fcd8:98f:ffff:ffff:ffff:ffff:ffff:ffff
154fcd8:990::/28fcd8:99f:ffff:ffff:ffff:ffff:ffff:ffff
155fcd8:9a0::/28fcd8:9af:ffff:ffff:ffff:ffff:ffff:ffff
156fcd8:9b0::/28fcd8:9bf:ffff:ffff:ffff:ffff:ffff:ffff
157fcd8:9c0::/28fcd8:9cf:ffff:ffff:ffff:ffff:ffff:ffff
158fcd8:9d0::/28fcd8:9df:ffff:ffff:ffff:ffff:ffff:ffff
159fcd8:9e0::/28fcd8:9ef:ffff:ffff:ffff:ffff:ffff:ffff
160fcd8:9f0::/28fcd8:9ff:ffff:ffff:ffff:ffff:ffff:ffff
161fcd8:a00::/28fcd8:a0f:ffff:ffff:ffff:ffff:ffff:ffff
162fcd8:a10::/28fcd8:a1f:ffff:ffff:ffff:ffff:ffff:ffff
163fcd8:a20::/28fcd8:a2f:ffff:ffff:ffff:ffff:ffff:ffff
164fcd8:a30::/28fcd8:a3f:ffff:ffff:ffff:ffff:ffff:ffff
165fcd8:a40::/28fcd8:a4f:ffff:ffff:ffff:ffff:ffff:ffff
166fcd8:a50::/28fcd8:a5f:ffff:ffff:ffff:ffff:ffff:ffff
167fcd8:a60::/28fcd8:a6f:ffff:ffff:ffff:ffff:ffff:ffff
168fcd8:a70::/28fcd8:a7f:ffff:ffff:ffff:ffff:ffff:ffff
169fcd8:a80::/28fcd8:a8f:ffff:ffff:ffff:ffff:ffff:ffff
170fcd8:a90::/28fcd8:a9f:ffff:ffff:ffff:ffff:ffff:ffff
171fcd8:aa0::/28fcd8:aaf:ffff:ffff:ffff:ffff:ffff:ffff
172fcd8:ab0::/28fcd8:abf:ffff:ffff:ffff:ffff:ffff:ffff
173fcd8:ac0::/28fcd8:acf:ffff:ffff:ffff:ffff:ffff:ffff
174fcd8:ad0::/28fcd8:adf:ffff:ffff:ffff:ffff:ffff:ffff
175fcd8:ae0::/28fcd8:aef:ffff:ffff:ffff:ffff:ffff:ffff
176fcd8:af0::/28fcd8:aff:ffff:ffff:ffff:ffff:ffff:ffff
177fcd8:b00::/28fcd8:b0f:ffff:ffff:ffff:ffff:ffff:ffff
178fcd8:b10::/28fcd8:b1f:ffff:ffff:ffff:ffff:ffff:ffff
179fcd8:b20::/28fcd8:b2f:ffff:ffff:ffff:ffff:ffff:ffff
180fcd8:b30::/28fcd8:b3f:ffff:ffff:ffff:ffff:ffff:ffff
181fcd8:b40::/28fcd8:b4f:ffff:ffff:ffff:ffff:ffff:ffff
182fcd8:b50::/28fcd8:b5f:ffff:ffff:ffff:ffff:ffff:ffff
183fcd8:b60::/28fcd8:b6f:ffff:ffff:ffff:ffff:ffff:ffff
184fcd8:b70::/28fcd8:b7f:ffff:ffff:ffff:ffff:ffff:ffff
185fcd8:b80::/28fcd8:b8f:ffff:ffff:ffff:ffff:ffff:ffff
186fcd8:b90::/28fcd8:b9f:ffff:ffff:ffff:ffff:ffff:ffff
187fcd8:ba0::/28fcd8:baf:ffff:ffff:ffff:ffff:ffff:ffff
188fcd8:bb0::/28fcd8:bbf:ffff:ffff:ffff:ffff:ffff:ffff
189fcd8:bc0::/28fcd8:bcf:ffff:ffff:ffff:ffff:ffff:ffff
190fcd8:bd0::/28fcd8:bdf:ffff:ffff:ffff:ffff:ffff:ffff
191fcd8:be0::/28fcd8:bef:ffff:ffff:ffff:ffff:ffff:ffff
192fcd8:bf0::/28fcd8:bff:ffff:ffff:ffff:ffff:ffff:ffff
193fcd8:c00::/28fcd8:c0f:ffff:ffff:ffff:ffff:ffff:ffff
194fcd8:c10::/28fcd8:c1f:ffff:ffff:ffff:ffff:ffff:ffff
195fcd8:c20::/28fcd8:c2f:ffff:ffff:ffff:ffff:ffff:ffff
196fcd8:c30::/28fcd8:c3f:ffff:ffff:ffff:ffff:ffff:ffff
197fcd8:c40::/28fcd8:c4f:ffff:ffff:ffff:ffff:ffff:ffff
198fcd8:c50::/28fcd8:c5f:ffff:ffff:ffff:ffff:ffff:ffff
199fcd8:c60::/28fcd8:c6f:ffff:ffff:ffff:ffff:ffff:ffff
200fcd8:c70::/28fcd8:c7f:ffff:ffff:ffff:ffff:ffff:ffff
201fcd8:c80::/28fcd8:c8f:ffff:ffff:ffff:ffff:ffff:ffff
202fcd8:c90::/28fcd8:c9f:ffff:ffff:ffff:ffff:ffff:ffff
203fcd8:ca0::/28fcd8:caf:ffff:ffff:ffff:ffff:ffff:ffff
204fcd8:cb0::/28fcd8:cbf:ffff:ffff:ffff:ffff:ffff:ffff
205fcd8:cc0::/28fcd8:ccf:ffff:ffff:ffff:ffff:ffff:ffff
206fcd8:cd0::/28fcd8:cdf:ffff:ffff:ffff:ffff:ffff:ffff
207fcd8:ce0::/28fcd8:cef:ffff:ffff:ffff:ffff:ffff:ffff
208fcd8:cf0::/28fcd8:cff:ffff:ffff:ffff:ffff:ffff:ffff
209fcd8:d00::/28fcd8:d0f:ffff:ffff:ffff:ffff:ffff:ffff
210fcd8:d10::/28fcd8:d1f:ffff:ffff:ffff:ffff:ffff:ffff
211fcd8:d20::/28fcd8:d2f:ffff:ffff:ffff:ffff:ffff:ffff
212fcd8:d30::/28fcd8:d3f:ffff:ffff:ffff:ffff:ffff:ffff
213fcd8:d40::/28fcd8:d4f:ffff:ffff:ffff:ffff:ffff:ffff
214fcd8:d50::/28fcd8:d5f:ffff:ffff:ffff:ffff:ffff:ffff
215fcd8:d60::/28fcd8:d6f:ffff:ffff:ffff:ffff:ffff:ffff
216fcd8:d70::/28fcd8:d7f:ffff:ffff:ffff:ffff:ffff:ffff
217fcd8:d80::/28fcd8:d8f:ffff:ffff:ffff:ffff:ffff:ffff
218fcd8:d90::/28fcd8:d9f:ffff:ffff:ffff:ffff:ffff:ffff
219fcd8:da0::/28fcd8:daf:ffff:ffff:ffff:ffff:ffff:ffff
220fcd8:db0::/28fcd8:dbf:ffff:ffff:ffff:ffff:ffff:ffff
221fcd8:dc0::/28fcd8:dcf:ffff:ffff:ffff:ffff:ffff:ffff
222fcd8:dd0::/28fcd8:ddf:ffff:ffff:ffff:ffff:ffff:ffff
223fcd8:de0::/28fcd8:def:ffff:ffff:ffff:ffff:ffff:ffff
224fcd8:df0::/28fcd8:dff:ffff:ffff:ffff:ffff:ffff:ffff
225fcd8:e00::/28fcd8:e0f:ffff:ffff:ffff:ffff:ffff:ffff
226fcd8:e10::/28fcd8:e1f:ffff:ffff:ffff:ffff:ffff:ffff
227fcd8:e20::/28fcd8:e2f:ffff:ffff:ffff:ffff:ffff:ffff
228fcd8:e30::/28fcd8:e3f:ffff:ffff:ffff:ffff:ffff:ffff
229fcd8:e40::/28fcd8:e4f:ffff:ffff:ffff:ffff:ffff:ffff
230fcd8:e50::/28fcd8:e5f:ffff:ffff:ffff:ffff:ffff:ffff
231fcd8:e60::/28fcd8:e6f:ffff:ffff:ffff:ffff:ffff:ffff
232fcd8:e70::/28fcd8:e7f:ffff:ffff:ffff:ffff:ffff:ffff
233fcd8:e80::/28fcd8:e8f:ffff:ffff:ffff:ffff:ffff:ffff
234fcd8:e90::/28fcd8:e9f:ffff:ffff:ffff:ffff:ffff:ffff
235fcd8:ea0::/28fcd8:eaf:ffff:ffff:ffff:ffff:ffff:ffff
236fcd8:eb0::/28fcd8:ebf:ffff:ffff:ffff:ffff:ffff:ffff
237fcd8:ec0::/28fcd8:ecf:ffff:ffff:ffff:ffff:ffff:ffff
238fcd8:ed0::/28fcd8:edf:ffff:ffff:ffff:ffff:ffff:ffff
239fcd8:ee0::/28fcd8:eef:ffff:ffff:ffff:ffff:ffff:ffff
240fcd8:ef0::/28fcd8:eff:ffff:ffff:ffff:ffff:ffff:ffff
241fcd8:f00::/28fcd8:f0f:ffff:ffff:ffff:ffff:ffff:ffff
242fcd8:f10::/28fcd8:f1f:ffff:ffff:ffff:ffff:ffff:ffff
243fcd8:f20::/28fcd8:f2f:ffff:ffff:ffff:ffff:ffff:ffff
244fcd8:f30::/28fcd8:f3f:ffff:ffff:ffff:ffff:ffff:ffff
245fcd8:f40::/28fcd8:f4f:ffff:ffff:ffff:ffff:ffff:ffff
246fcd8:f50::/28fcd8:f5f:ffff:ffff:ffff:ffff:ffff:ffff
247fcd8:f60::/28fcd8:f6f:ffff:ffff:ffff:ffff:ffff:ffff
248fcd8:f70::/28fcd8:f7f:ffff:ffff:ffff:ffff:ffff:ffff
249fcd8:f80::/28fcd8:f8f:ffff:ffff:ffff:ffff:ffff:ffff
250fcd8:f90::/28fcd8:f9f:ffff:ffff:ffff:ffff:ffff:ffff
251fcd8:fa0::/28fcd8:faf:ffff:ffff:ffff:ffff:ffff:ffff
252fcd8:fb0::/28fcd8:fbf:ffff:ffff:ffff:ffff:ffff:ffff
253fcd8:fc0::/28fcd8:fcf:ffff:ffff:ffff:ffff:ffff:ffff
254fcd8:fd0::/28fcd8:fdf:ffff:ffff:ffff:ffff:ffff:ffff
255fcd8:fe0::/28fcd8:fef:ffff:ffff:ffff:ffff:ffff:ffff
256fcd8:ff0::/28fcd8: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.