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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
fcd2::/16
First address
fcd2::
Last address
fcd2: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
fcd2:0000:0000:0000:0000:0000:0000:0000
Type
Unique local (ULA) fc00::/7
Private IPv6, like RFC 1918; usually fd00::/8
Reverse DNS zone
2.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)

fcd2::/16 makes 4,096 subnets of /28; the first 256 are listed.

Subnets
#SubnetLast address
1fcd2::/28fcd2:f:ffff:ffff:ffff:ffff:ffff:ffff
2fcd2:10::/28fcd2:1f:ffff:ffff:ffff:ffff:ffff:ffff
3fcd2:20::/28fcd2:2f:ffff:ffff:ffff:ffff:ffff:ffff
4fcd2:30::/28fcd2:3f:ffff:ffff:ffff:ffff:ffff:ffff
5fcd2:40::/28fcd2:4f:ffff:ffff:ffff:ffff:ffff:ffff
6fcd2:50::/28fcd2:5f:ffff:ffff:ffff:ffff:ffff:ffff
7fcd2:60::/28fcd2:6f:ffff:ffff:ffff:ffff:ffff:ffff
8fcd2:70::/28fcd2:7f:ffff:ffff:ffff:ffff:ffff:ffff
9fcd2:80::/28fcd2:8f:ffff:ffff:ffff:ffff:ffff:ffff
10fcd2:90::/28fcd2:9f:ffff:ffff:ffff:ffff:ffff:ffff
11fcd2:a0::/28fcd2:af:ffff:ffff:ffff:ffff:ffff:ffff
12fcd2:b0::/28fcd2:bf:ffff:ffff:ffff:ffff:ffff:ffff
13fcd2:c0::/28fcd2:cf:ffff:ffff:ffff:ffff:ffff:ffff
14fcd2:d0::/28fcd2:df:ffff:ffff:ffff:ffff:ffff:ffff
15fcd2:e0::/28fcd2:ef:ffff:ffff:ffff:ffff:ffff:ffff
16fcd2:f0::/28fcd2:ff:ffff:ffff:ffff:ffff:ffff:ffff
17fcd2:100::/28fcd2:10f:ffff:ffff:ffff:ffff:ffff:ffff
18fcd2:110::/28fcd2:11f:ffff:ffff:ffff:ffff:ffff:ffff
19fcd2:120::/28fcd2:12f:ffff:ffff:ffff:ffff:ffff:ffff
20fcd2:130::/28fcd2:13f:ffff:ffff:ffff:ffff:ffff:ffff
21fcd2:140::/28fcd2:14f:ffff:ffff:ffff:ffff:ffff:ffff
22fcd2:150::/28fcd2:15f:ffff:ffff:ffff:ffff:ffff:ffff
23fcd2:160::/28fcd2:16f:ffff:ffff:ffff:ffff:ffff:ffff
24fcd2:170::/28fcd2:17f:ffff:ffff:ffff:ffff:ffff:ffff
25fcd2:180::/28fcd2:18f:ffff:ffff:ffff:ffff:ffff:ffff
26fcd2:190::/28fcd2:19f:ffff:ffff:ffff:ffff:ffff:ffff
27fcd2:1a0::/28fcd2:1af:ffff:ffff:ffff:ffff:ffff:ffff
28fcd2:1b0::/28fcd2:1bf:ffff:ffff:ffff:ffff:ffff:ffff
29fcd2:1c0::/28fcd2:1cf:ffff:ffff:ffff:ffff:ffff:ffff
30fcd2:1d0::/28fcd2:1df:ffff:ffff:ffff:ffff:ffff:ffff
31fcd2:1e0::/28fcd2:1ef:ffff:ffff:ffff:ffff:ffff:ffff
32fcd2:1f0::/28fcd2:1ff:ffff:ffff:ffff:ffff:ffff:ffff
33fcd2:200::/28fcd2:20f:ffff:ffff:ffff:ffff:ffff:ffff
34fcd2:210::/28fcd2:21f:ffff:ffff:ffff:ffff:ffff:ffff
35fcd2:220::/28fcd2:22f:ffff:ffff:ffff:ffff:ffff:ffff
36fcd2:230::/28fcd2:23f:ffff:ffff:ffff:ffff:ffff:ffff
37fcd2:240::/28fcd2:24f:ffff:ffff:ffff:ffff:ffff:ffff
38fcd2:250::/28fcd2:25f:ffff:ffff:ffff:ffff:ffff:ffff
39fcd2:260::/28fcd2:26f:ffff:ffff:ffff:ffff:ffff:ffff
40fcd2:270::/28fcd2:27f:ffff:ffff:ffff:ffff:ffff:ffff
41fcd2:280::/28fcd2:28f:ffff:ffff:ffff:ffff:ffff:ffff
42fcd2:290::/28fcd2:29f:ffff:ffff:ffff:ffff:ffff:ffff
43fcd2:2a0::/28fcd2:2af:ffff:ffff:ffff:ffff:ffff:ffff
44fcd2:2b0::/28fcd2:2bf:ffff:ffff:ffff:ffff:ffff:ffff
45fcd2:2c0::/28fcd2:2cf:ffff:ffff:ffff:ffff:ffff:ffff
46fcd2:2d0::/28fcd2:2df:ffff:ffff:ffff:ffff:ffff:ffff
47fcd2:2e0::/28fcd2:2ef:ffff:ffff:ffff:ffff:ffff:ffff
48fcd2:2f0::/28fcd2:2ff:ffff:ffff:ffff:ffff:ffff:ffff
49fcd2:300::/28fcd2:30f:ffff:ffff:ffff:ffff:ffff:ffff
50fcd2:310::/28fcd2:31f:ffff:ffff:ffff:ffff:ffff:ffff
51fcd2:320::/28fcd2:32f:ffff:ffff:ffff:ffff:ffff:ffff
52fcd2:330::/28fcd2:33f:ffff:ffff:ffff:ffff:ffff:ffff
53fcd2:340::/28fcd2:34f:ffff:ffff:ffff:ffff:ffff:ffff
54fcd2:350::/28fcd2:35f:ffff:ffff:ffff:ffff:ffff:ffff
55fcd2:360::/28fcd2:36f:ffff:ffff:ffff:ffff:ffff:ffff
56fcd2:370::/28fcd2:37f:ffff:ffff:ffff:ffff:ffff:ffff
57fcd2:380::/28fcd2:38f:ffff:ffff:ffff:ffff:ffff:ffff
58fcd2:390::/28fcd2:39f:ffff:ffff:ffff:ffff:ffff:ffff
59fcd2:3a0::/28fcd2:3af:ffff:ffff:ffff:ffff:ffff:ffff
60fcd2:3b0::/28fcd2:3bf:ffff:ffff:ffff:ffff:ffff:ffff
61fcd2:3c0::/28fcd2:3cf:ffff:ffff:ffff:ffff:ffff:ffff
62fcd2:3d0::/28fcd2:3df:ffff:ffff:ffff:ffff:ffff:ffff
63fcd2:3e0::/28fcd2:3ef:ffff:ffff:ffff:ffff:ffff:ffff
64fcd2:3f0::/28fcd2:3ff:ffff:ffff:ffff:ffff:ffff:ffff
65fcd2:400::/28fcd2:40f:ffff:ffff:ffff:ffff:ffff:ffff
66fcd2:410::/28fcd2:41f:ffff:ffff:ffff:ffff:ffff:ffff
67fcd2:420::/28fcd2:42f:ffff:ffff:ffff:ffff:ffff:ffff
68fcd2:430::/28fcd2:43f:ffff:ffff:ffff:ffff:ffff:ffff
69fcd2:440::/28fcd2:44f:ffff:ffff:ffff:ffff:ffff:ffff
70fcd2:450::/28fcd2:45f:ffff:ffff:ffff:ffff:ffff:ffff
71fcd2:460::/28fcd2:46f:ffff:ffff:ffff:ffff:ffff:ffff
72fcd2:470::/28fcd2:47f:ffff:ffff:ffff:ffff:ffff:ffff
73fcd2:480::/28fcd2:48f:ffff:ffff:ffff:ffff:ffff:ffff
74fcd2:490::/28fcd2:49f:ffff:ffff:ffff:ffff:ffff:ffff
75fcd2:4a0::/28fcd2:4af:ffff:ffff:ffff:ffff:ffff:ffff
76fcd2:4b0::/28fcd2:4bf:ffff:ffff:ffff:ffff:ffff:ffff
77fcd2:4c0::/28fcd2:4cf:ffff:ffff:ffff:ffff:ffff:ffff
78fcd2:4d0::/28fcd2:4df:ffff:ffff:ffff:ffff:ffff:ffff
79fcd2:4e0::/28fcd2:4ef:ffff:ffff:ffff:ffff:ffff:ffff
80fcd2:4f0::/28fcd2:4ff:ffff:ffff:ffff:ffff:ffff:ffff
81fcd2:500::/28fcd2:50f:ffff:ffff:ffff:ffff:ffff:ffff
82fcd2:510::/28fcd2:51f:ffff:ffff:ffff:ffff:ffff:ffff
83fcd2:520::/28fcd2:52f:ffff:ffff:ffff:ffff:ffff:ffff
84fcd2:530::/28fcd2:53f:ffff:ffff:ffff:ffff:ffff:ffff
85fcd2:540::/28fcd2:54f:ffff:ffff:ffff:ffff:ffff:ffff
86fcd2:550::/28fcd2:55f:ffff:ffff:ffff:ffff:ffff:ffff
87fcd2:560::/28fcd2:56f:ffff:ffff:ffff:ffff:ffff:ffff
88fcd2:570::/28fcd2:57f:ffff:ffff:ffff:ffff:ffff:ffff
89fcd2:580::/28fcd2:58f:ffff:ffff:ffff:ffff:ffff:ffff
90fcd2:590::/28fcd2:59f:ffff:ffff:ffff:ffff:ffff:ffff
91fcd2:5a0::/28fcd2:5af:ffff:ffff:ffff:ffff:ffff:ffff
92fcd2:5b0::/28fcd2:5bf:ffff:ffff:ffff:ffff:ffff:ffff
93fcd2:5c0::/28fcd2:5cf:ffff:ffff:ffff:ffff:ffff:ffff
94fcd2:5d0::/28fcd2:5df:ffff:ffff:ffff:ffff:ffff:ffff
95fcd2:5e0::/28fcd2:5ef:ffff:ffff:ffff:ffff:ffff:ffff
96fcd2:5f0::/28fcd2:5ff:ffff:ffff:ffff:ffff:ffff:ffff
97fcd2:600::/28fcd2:60f:ffff:ffff:ffff:ffff:ffff:ffff
98fcd2:610::/28fcd2:61f:ffff:ffff:ffff:ffff:ffff:ffff
99fcd2:620::/28fcd2:62f:ffff:ffff:ffff:ffff:ffff:ffff
100fcd2:630::/28fcd2:63f:ffff:ffff:ffff:ffff:ffff:ffff
101fcd2:640::/28fcd2:64f:ffff:ffff:ffff:ffff:ffff:ffff
102fcd2:650::/28fcd2:65f:ffff:ffff:ffff:ffff:ffff:ffff
103fcd2:660::/28fcd2:66f:ffff:ffff:ffff:ffff:ffff:ffff
104fcd2:670::/28fcd2:67f:ffff:ffff:ffff:ffff:ffff:ffff
105fcd2:680::/28fcd2:68f:ffff:ffff:ffff:ffff:ffff:ffff
106fcd2:690::/28fcd2:69f:ffff:ffff:ffff:ffff:ffff:ffff
107fcd2:6a0::/28fcd2:6af:ffff:ffff:ffff:ffff:ffff:ffff
108fcd2:6b0::/28fcd2:6bf:ffff:ffff:ffff:ffff:ffff:ffff
109fcd2:6c0::/28fcd2:6cf:ffff:ffff:ffff:ffff:ffff:ffff
110fcd2:6d0::/28fcd2:6df:ffff:ffff:ffff:ffff:ffff:ffff
111fcd2:6e0::/28fcd2:6ef:ffff:ffff:ffff:ffff:ffff:ffff
112fcd2:6f0::/28fcd2:6ff:ffff:ffff:ffff:ffff:ffff:ffff
113fcd2:700::/28fcd2:70f:ffff:ffff:ffff:ffff:ffff:ffff
114fcd2:710::/28fcd2:71f:ffff:ffff:ffff:ffff:ffff:ffff
115fcd2:720::/28fcd2:72f:ffff:ffff:ffff:ffff:ffff:ffff
116fcd2:730::/28fcd2:73f:ffff:ffff:ffff:ffff:ffff:ffff
117fcd2:740::/28fcd2:74f:ffff:ffff:ffff:ffff:ffff:ffff
118fcd2:750::/28fcd2:75f:ffff:ffff:ffff:ffff:ffff:ffff
119fcd2:760::/28fcd2:76f:ffff:ffff:ffff:ffff:ffff:ffff
120fcd2:770::/28fcd2:77f:ffff:ffff:ffff:ffff:ffff:ffff
121fcd2:780::/28fcd2:78f:ffff:ffff:ffff:ffff:ffff:ffff
122fcd2:790::/28fcd2:79f:ffff:ffff:ffff:ffff:ffff:ffff
123fcd2:7a0::/28fcd2:7af:ffff:ffff:ffff:ffff:ffff:ffff
124fcd2:7b0::/28fcd2:7bf:ffff:ffff:ffff:ffff:ffff:ffff
125fcd2:7c0::/28fcd2:7cf:ffff:ffff:ffff:ffff:ffff:ffff
126fcd2:7d0::/28fcd2:7df:ffff:ffff:ffff:ffff:ffff:ffff
127fcd2:7e0::/28fcd2:7ef:ffff:ffff:ffff:ffff:ffff:ffff
128fcd2:7f0::/28fcd2:7ff:ffff:ffff:ffff:ffff:ffff:ffff
129fcd2:800::/28fcd2:80f:ffff:ffff:ffff:ffff:ffff:ffff
130fcd2:810::/28fcd2:81f:ffff:ffff:ffff:ffff:ffff:ffff
131fcd2:820::/28fcd2:82f:ffff:ffff:ffff:ffff:ffff:ffff
132fcd2:830::/28fcd2:83f:ffff:ffff:ffff:ffff:ffff:ffff
133fcd2:840::/28fcd2:84f:ffff:ffff:ffff:ffff:ffff:ffff
134fcd2:850::/28fcd2:85f:ffff:ffff:ffff:ffff:ffff:ffff
135fcd2:860::/28fcd2:86f:ffff:ffff:ffff:ffff:ffff:ffff
136fcd2:870::/28fcd2:87f:ffff:ffff:ffff:ffff:ffff:ffff
137fcd2:880::/28fcd2:88f:ffff:ffff:ffff:ffff:ffff:ffff
138fcd2:890::/28fcd2:89f:ffff:ffff:ffff:ffff:ffff:ffff
139fcd2:8a0::/28fcd2:8af:ffff:ffff:ffff:ffff:ffff:ffff
140fcd2:8b0::/28fcd2:8bf:ffff:ffff:ffff:ffff:ffff:ffff
141fcd2:8c0::/28fcd2:8cf:ffff:ffff:ffff:ffff:ffff:ffff
142fcd2:8d0::/28fcd2:8df:ffff:ffff:ffff:ffff:ffff:ffff
143fcd2:8e0::/28fcd2:8ef:ffff:ffff:ffff:ffff:ffff:ffff
144fcd2:8f0::/28fcd2:8ff:ffff:ffff:ffff:ffff:ffff:ffff
145fcd2:900::/28fcd2:90f:ffff:ffff:ffff:ffff:ffff:ffff
146fcd2:910::/28fcd2:91f:ffff:ffff:ffff:ffff:ffff:ffff
147fcd2:920::/28fcd2:92f:ffff:ffff:ffff:ffff:ffff:ffff
148fcd2:930::/28fcd2:93f:ffff:ffff:ffff:ffff:ffff:ffff
149fcd2:940::/28fcd2:94f:ffff:ffff:ffff:ffff:ffff:ffff
150fcd2:950::/28fcd2:95f:ffff:ffff:ffff:ffff:ffff:ffff
151fcd2:960::/28fcd2:96f:ffff:ffff:ffff:ffff:ffff:ffff
152fcd2:970::/28fcd2:97f:ffff:ffff:ffff:ffff:ffff:ffff
153fcd2:980::/28fcd2:98f:ffff:ffff:ffff:ffff:ffff:ffff
154fcd2:990::/28fcd2:99f:ffff:ffff:ffff:ffff:ffff:ffff
155fcd2:9a0::/28fcd2:9af:ffff:ffff:ffff:ffff:ffff:ffff
156fcd2:9b0::/28fcd2:9bf:ffff:ffff:ffff:ffff:ffff:ffff
157fcd2:9c0::/28fcd2:9cf:ffff:ffff:ffff:ffff:ffff:ffff
158fcd2:9d0::/28fcd2:9df:ffff:ffff:ffff:ffff:ffff:ffff
159fcd2:9e0::/28fcd2:9ef:ffff:ffff:ffff:ffff:ffff:ffff
160fcd2:9f0::/28fcd2:9ff:ffff:ffff:ffff:ffff:ffff:ffff
161fcd2:a00::/28fcd2:a0f:ffff:ffff:ffff:ffff:ffff:ffff
162fcd2:a10::/28fcd2:a1f:ffff:ffff:ffff:ffff:ffff:ffff
163fcd2:a20::/28fcd2:a2f:ffff:ffff:ffff:ffff:ffff:ffff
164fcd2:a30::/28fcd2:a3f:ffff:ffff:ffff:ffff:ffff:ffff
165fcd2:a40::/28fcd2:a4f:ffff:ffff:ffff:ffff:ffff:ffff
166fcd2:a50::/28fcd2:a5f:ffff:ffff:ffff:ffff:ffff:ffff
167fcd2:a60::/28fcd2:a6f:ffff:ffff:ffff:ffff:ffff:ffff
168fcd2:a70::/28fcd2:a7f:ffff:ffff:ffff:ffff:ffff:ffff
169fcd2:a80::/28fcd2:a8f:ffff:ffff:ffff:ffff:ffff:ffff
170fcd2:a90::/28fcd2:a9f:ffff:ffff:ffff:ffff:ffff:ffff
171fcd2:aa0::/28fcd2:aaf:ffff:ffff:ffff:ffff:ffff:ffff
172fcd2:ab0::/28fcd2:abf:ffff:ffff:ffff:ffff:ffff:ffff
173fcd2:ac0::/28fcd2:acf:ffff:ffff:ffff:ffff:ffff:ffff
174fcd2:ad0::/28fcd2:adf:ffff:ffff:ffff:ffff:ffff:ffff
175fcd2:ae0::/28fcd2:aef:ffff:ffff:ffff:ffff:ffff:ffff
176fcd2:af0::/28fcd2:aff:ffff:ffff:ffff:ffff:ffff:ffff
177fcd2:b00::/28fcd2:b0f:ffff:ffff:ffff:ffff:ffff:ffff
178fcd2:b10::/28fcd2:b1f:ffff:ffff:ffff:ffff:ffff:ffff
179fcd2:b20::/28fcd2:b2f:ffff:ffff:ffff:ffff:ffff:ffff
180fcd2:b30::/28fcd2:b3f:ffff:ffff:ffff:ffff:ffff:ffff
181fcd2:b40::/28fcd2:b4f:ffff:ffff:ffff:ffff:ffff:ffff
182fcd2:b50::/28fcd2:b5f:ffff:ffff:ffff:ffff:ffff:ffff
183fcd2:b60::/28fcd2:b6f:ffff:ffff:ffff:ffff:ffff:ffff
184fcd2:b70::/28fcd2:b7f:ffff:ffff:ffff:ffff:ffff:ffff
185fcd2:b80::/28fcd2:b8f:ffff:ffff:ffff:ffff:ffff:ffff
186fcd2:b90::/28fcd2:b9f:ffff:ffff:ffff:ffff:ffff:ffff
187fcd2:ba0::/28fcd2:baf:ffff:ffff:ffff:ffff:ffff:ffff
188fcd2:bb0::/28fcd2:bbf:ffff:ffff:ffff:ffff:ffff:ffff
189fcd2:bc0::/28fcd2:bcf:ffff:ffff:ffff:ffff:ffff:ffff
190fcd2:bd0::/28fcd2:bdf:ffff:ffff:ffff:ffff:ffff:ffff
191fcd2:be0::/28fcd2:bef:ffff:ffff:ffff:ffff:ffff:ffff
192fcd2:bf0::/28fcd2:bff:ffff:ffff:ffff:ffff:ffff:ffff
193fcd2:c00::/28fcd2:c0f:ffff:ffff:ffff:ffff:ffff:ffff
194fcd2:c10::/28fcd2:c1f:ffff:ffff:ffff:ffff:ffff:ffff
195fcd2:c20::/28fcd2:c2f:ffff:ffff:ffff:ffff:ffff:ffff
196fcd2:c30::/28fcd2:c3f:ffff:ffff:ffff:ffff:ffff:ffff
197fcd2:c40::/28fcd2:c4f:ffff:ffff:ffff:ffff:ffff:ffff
198fcd2:c50::/28fcd2:c5f:ffff:ffff:ffff:ffff:ffff:ffff
199fcd2:c60::/28fcd2:c6f:ffff:ffff:ffff:ffff:ffff:ffff
200fcd2:c70::/28fcd2:c7f:ffff:ffff:ffff:ffff:ffff:ffff
201fcd2:c80::/28fcd2:c8f:ffff:ffff:ffff:ffff:ffff:ffff
202fcd2:c90::/28fcd2:c9f:ffff:ffff:ffff:ffff:ffff:ffff
203fcd2:ca0::/28fcd2:caf:ffff:ffff:ffff:ffff:ffff:ffff
204fcd2:cb0::/28fcd2:cbf:ffff:ffff:ffff:ffff:ffff:ffff
205fcd2:cc0::/28fcd2:ccf:ffff:ffff:ffff:ffff:ffff:ffff
206fcd2:cd0::/28fcd2:cdf:ffff:ffff:ffff:ffff:ffff:ffff
207fcd2:ce0::/28fcd2:cef:ffff:ffff:ffff:ffff:ffff:ffff
208fcd2:cf0::/28fcd2:cff:ffff:ffff:ffff:ffff:ffff:ffff
209fcd2:d00::/28fcd2:d0f:ffff:ffff:ffff:ffff:ffff:ffff
210fcd2:d10::/28fcd2:d1f:ffff:ffff:ffff:ffff:ffff:ffff
211fcd2:d20::/28fcd2:d2f:ffff:ffff:ffff:ffff:ffff:ffff
212fcd2:d30::/28fcd2:d3f:ffff:ffff:ffff:ffff:ffff:ffff
213fcd2:d40::/28fcd2:d4f:ffff:ffff:ffff:ffff:ffff:ffff
214fcd2:d50::/28fcd2:d5f:ffff:ffff:ffff:ffff:ffff:ffff
215fcd2:d60::/28fcd2:d6f:ffff:ffff:ffff:ffff:ffff:ffff
216fcd2:d70::/28fcd2:d7f:ffff:ffff:ffff:ffff:ffff:ffff
217fcd2:d80::/28fcd2:d8f:ffff:ffff:ffff:ffff:ffff:ffff
218fcd2:d90::/28fcd2:d9f:ffff:ffff:ffff:ffff:ffff:ffff
219fcd2:da0::/28fcd2:daf:ffff:ffff:ffff:ffff:ffff:ffff
220fcd2:db0::/28fcd2:dbf:ffff:ffff:ffff:ffff:ffff:ffff
221fcd2:dc0::/28fcd2:dcf:ffff:ffff:ffff:ffff:ffff:ffff
222fcd2:dd0::/28fcd2:ddf:ffff:ffff:ffff:ffff:ffff:ffff
223fcd2:de0::/28fcd2:def:ffff:ffff:ffff:ffff:ffff:ffff
224fcd2:df0::/28fcd2:dff:ffff:ffff:ffff:ffff:ffff:ffff
225fcd2:e00::/28fcd2:e0f:ffff:ffff:ffff:ffff:ffff:ffff
226fcd2:e10::/28fcd2:e1f:ffff:ffff:ffff:ffff:ffff:ffff
227fcd2:e20::/28fcd2:e2f:ffff:ffff:ffff:ffff:ffff:ffff
228fcd2:e30::/28fcd2:e3f:ffff:ffff:ffff:ffff:ffff:ffff
229fcd2:e40::/28fcd2:e4f:ffff:ffff:ffff:ffff:ffff:ffff
230fcd2:e50::/28fcd2:e5f:ffff:ffff:ffff:ffff:ffff:ffff
231fcd2:e60::/28fcd2:e6f:ffff:ffff:ffff:ffff:ffff:ffff
232fcd2:e70::/28fcd2:e7f:ffff:ffff:ffff:ffff:ffff:ffff
233fcd2:e80::/28fcd2:e8f:ffff:ffff:ffff:ffff:ffff:ffff
234fcd2:e90::/28fcd2:e9f:ffff:ffff:ffff:ffff:ffff:ffff
235fcd2:ea0::/28fcd2:eaf:ffff:ffff:ffff:ffff:ffff:ffff
236fcd2:eb0::/28fcd2:ebf:ffff:ffff:ffff:ffff:ffff:ffff
237fcd2:ec0::/28fcd2:ecf:ffff:ffff:ffff:ffff:ffff:ffff
238fcd2:ed0::/28fcd2:edf:ffff:ffff:ffff:ffff:ffff:ffff
239fcd2:ee0::/28fcd2:eef:ffff:ffff:ffff:ffff:ffff:ffff
240fcd2:ef0::/28fcd2:eff:ffff:ffff:ffff:ffff:ffff:ffff
241fcd2:f00::/28fcd2:f0f:ffff:ffff:ffff:ffff:ffff:ffff
242fcd2:f10::/28fcd2:f1f:ffff:ffff:ffff:ffff:ffff:ffff
243fcd2:f20::/28fcd2:f2f:ffff:ffff:ffff:ffff:ffff:ffff
244fcd2:f30::/28fcd2:f3f:ffff:ffff:ffff:ffff:ffff:ffff
245fcd2:f40::/28fcd2:f4f:ffff:ffff:ffff:ffff:ffff:ffff
246fcd2:f50::/28fcd2:f5f:ffff:ffff:ffff:ffff:ffff:ffff
247fcd2:f60::/28fcd2:f6f:ffff:ffff:ffff:ffff:ffff:ffff
248fcd2:f70::/28fcd2:f7f:ffff:ffff:ffff:ffff:ffff:ffff
249fcd2:f80::/28fcd2:f8f:ffff:ffff:ffff:ffff:ffff:ffff
250fcd2:f90::/28fcd2:f9f:ffff:ffff:ffff:ffff:ffff:ffff
251fcd2:fa0::/28fcd2:faf:ffff:ffff:ffff:ffff:ffff:ffff
252fcd2:fb0::/28fcd2:fbf:ffff:ffff:ffff:ffff:ffff:ffff
253fcd2:fc0::/28fcd2:fcf:ffff:ffff:ffff:ffff:ffff:ffff
254fcd2:fd0::/28fcd2:fdf:ffff:ffff:ffff:ffff:ffff:ffff
255fcd2:fe0::/28fcd2:fef:ffff:ffff:ffff:ffff:ffff:ffff
256fcd2:ff0::/28fcd2: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.