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

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

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