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

fceb::/16 makes 256 subnets of /24.

Subnets
#SubnetLast address
1fceb::/24fceb:ff:ffff:ffff:ffff:ffff:ffff:ffff
2fceb:100::/24fceb:1ff:ffff:ffff:ffff:ffff:ffff:ffff
3fceb:200::/24fceb:2ff:ffff:ffff:ffff:ffff:ffff:ffff
4fceb:300::/24fceb:3ff:ffff:ffff:ffff:ffff:ffff:ffff
5fceb:400::/24fceb:4ff:ffff:ffff:ffff:ffff:ffff:ffff
6fceb:500::/24fceb:5ff:ffff:ffff:ffff:ffff:ffff:ffff
7fceb:600::/24fceb:6ff:ffff:ffff:ffff:ffff:ffff:ffff
8fceb:700::/24fceb:7ff:ffff:ffff:ffff:ffff:ffff:ffff
9fceb:800::/24fceb:8ff:ffff:ffff:ffff:ffff:ffff:ffff
10fceb:900::/24fceb:9ff:ffff:ffff:ffff:ffff:ffff:ffff
11fceb:a00::/24fceb:aff:ffff:ffff:ffff:ffff:ffff:ffff
12fceb:b00::/24fceb:bff:ffff:ffff:ffff:ffff:ffff:ffff
13fceb:c00::/24fceb:cff:ffff:ffff:ffff:ffff:ffff:ffff
14fceb:d00::/24fceb:dff:ffff:ffff:ffff:ffff:ffff:ffff
15fceb:e00::/24fceb:eff:ffff:ffff:ffff:ffff:ffff:ffff
16fceb:f00::/24fceb:fff:ffff:ffff:ffff:ffff:ffff:ffff
17fceb:1000::/24fceb:10ff:ffff:ffff:ffff:ffff:ffff:ffff
18fceb:1100::/24fceb:11ff:ffff:ffff:ffff:ffff:ffff:ffff
19fceb:1200::/24fceb:12ff:ffff:ffff:ffff:ffff:ffff:ffff
20fceb:1300::/24fceb:13ff:ffff:ffff:ffff:ffff:ffff:ffff
21fceb:1400::/24fceb:14ff:ffff:ffff:ffff:ffff:ffff:ffff
22fceb:1500::/24fceb:15ff:ffff:ffff:ffff:ffff:ffff:ffff
23fceb:1600::/24fceb:16ff:ffff:ffff:ffff:ffff:ffff:ffff
24fceb:1700::/24fceb:17ff:ffff:ffff:ffff:ffff:ffff:ffff
25fceb:1800::/24fceb:18ff:ffff:ffff:ffff:ffff:ffff:ffff
26fceb:1900::/24fceb:19ff:ffff:ffff:ffff:ffff:ffff:ffff
27fceb:1a00::/24fceb:1aff:ffff:ffff:ffff:ffff:ffff:ffff
28fceb:1b00::/24fceb:1bff:ffff:ffff:ffff:ffff:ffff:ffff
29fceb:1c00::/24fceb:1cff:ffff:ffff:ffff:ffff:ffff:ffff
30fceb:1d00::/24fceb:1dff:ffff:ffff:ffff:ffff:ffff:ffff
31fceb:1e00::/24fceb:1eff:ffff:ffff:ffff:ffff:ffff:ffff
32fceb:1f00::/24fceb:1fff:ffff:ffff:ffff:ffff:ffff:ffff
33fceb:2000::/24fceb:20ff:ffff:ffff:ffff:ffff:ffff:ffff
34fceb:2100::/24fceb:21ff:ffff:ffff:ffff:ffff:ffff:ffff
35fceb:2200::/24fceb:22ff:ffff:ffff:ffff:ffff:ffff:ffff
36fceb:2300::/24fceb:23ff:ffff:ffff:ffff:ffff:ffff:ffff
37fceb:2400::/24fceb:24ff:ffff:ffff:ffff:ffff:ffff:ffff
38fceb:2500::/24fceb:25ff:ffff:ffff:ffff:ffff:ffff:ffff
39fceb:2600::/24fceb:26ff:ffff:ffff:ffff:ffff:ffff:ffff
40fceb:2700::/24fceb:27ff:ffff:ffff:ffff:ffff:ffff:ffff
41fceb:2800::/24fceb:28ff:ffff:ffff:ffff:ffff:ffff:ffff
42fceb:2900::/24fceb:29ff:ffff:ffff:ffff:ffff:ffff:ffff
43fceb:2a00::/24fceb:2aff:ffff:ffff:ffff:ffff:ffff:ffff
44fceb:2b00::/24fceb:2bff:ffff:ffff:ffff:ffff:ffff:ffff
45fceb:2c00::/24fceb:2cff:ffff:ffff:ffff:ffff:ffff:ffff
46fceb:2d00::/24fceb:2dff:ffff:ffff:ffff:ffff:ffff:ffff
47fceb:2e00::/24fceb:2eff:ffff:ffff:ffff:ffff:ffff:ffff
48fceb:2f00::/24fceb:2fff:ffff:ffff:ffff:ffff:ffff:ffff
49fceb:3000::/24fceb:30ff:ffff:ffff:ffff:ffff:ffff:ffff
50fceb:3100::/24fceb:31ff:ffff:ffff:ffff:ffff:ffff:ffff
51fceb:3200::/24fceb:32ff:ffff:ffff:ffff:ffff:ffff:ffff
52fceb:3300::/24fceb:33ff:ffff:ffff:ffff:ffff:ffff:ffff
53fceb:3400::/24fceb:34ff:ffff:ffff:ffff:ffff:ffff:ffff
54fceb:3500::/24fceb:35ff:ffff:ffff:ffff:ffff:ffff:ffff
55fceb:3600::/24fceb:36ff:ffff:ffff:ffff:ffff:ffff:ffff
56fceb:3700::/24fceb:37ff:ffff:ffff:ffff:ffff:ffff:ffff
57fceb:3800::/24fceb:38ff:ffff:ffff:ffff:ffff:ffff:ffff
58fceb:3900::/24fceb:39ff:ffff:ffff:ffff:ffff:ffff:ffff
59fceb:3a00::/24fceb:3aff:ffff:ffff:ffff:ffff:ffff:ffff
60fceb:3b00::/24fceb:3bff:ffff:ffff:ffff:ffff:ffff:ffff
61fceb:3c00::/24fceb:3cff:ffff:ffff:ffff:ffff:ffff:ffff
62fceb:3d00::/24fceb:3dff:ffff:ffff:ffff:ffff:ffff:ffff
63fceb:3e00::/24fceb:3eff:ffff:ffff:ffff:ffff:ffff:ffff
64fceb:3f00::/24fceb:3fff:ffff:ffff:ffff:ffff:ffff:ffff
65fceb:4000::/24fceb:40ff:ffff:ffff:ffff:ffff:ffff:ffff
66fceb:4100::/24fceb:41ff:ffff:ffff:ffff:ffff:ffff:ffff
67fceb:4200::/24fceb:42ff:ffff:ffff:ffff:ffff:ffff:ffff
68fceb:4300::/24fceb:43ff:ffff:ffff:ffff:ffff:ffff:ffff
69fceb:4400::/24fceb:44ff:ffff:ffff:ffff:ffff:ffff:ffff
70fceb:4500::/24fceb:45ff:ffff:ffff:ffff:ffff:ffff:ffff
71fceb:4600::/24fceb:46ff:ffff:ffff:ffff:ffff:ffff:ffff
72fceb:4700::/24fceb:47ff:ffff:ffff:ffff:ffff:ffff:ffff
73fceb:4800::/24fceb:48ff:ffff:ffff:ffff:ffff:ffff:ffff
74fceb:4900::/24fceb:49ff:ffff:ffff:ffff:ffff:ffff:ffff
75fceb:4a00::/24fceb:4aff:ffff:ffff:ffff:ffff:ffff:ffff
76fceb:4b00::/24fceb:4bff:ffff:ffff:ffff:ffff:ffff:ffff
77fceb:4c00::/24fceb:4cff:ffff:ffff:ffff:ffff:ffff:ffff
78fceb:4d00::/24fceb:4dff:ffff:ffff:ffff:ffff:ffff:ffff
79fceb:4e00::/24fceb:4eff:ffff:ffff:ffff:ffff:ffff:ffff
80fceb:4f00::/24fceb:4fff:ffff:ffff:ffff:ffff:ffff:ffff
81fceb:5000::/24fceb:50ff:ffff:ffff:ffff:ffff:ffff:ffff
82fceb:5100::/24fceb:51ff:ffff:ffff:ffff:ffff:ffff:ffff
83fceb:5200::/24fceb:52ff:ffff:ffff:ffff:ffff:ffff:ffff
84fceb:5300::/24fceb:53ff:ffff:ffff:ffff:ffff:ffff:ffff
85fceb:5400::/24fceb:54ff:ffff:ffff:ffff:ffff:ffff:ffff
86fceb:5500::/24fceb:55ff:ffff:ffff:ffff:ffff:ffff:ffff
87fceb:5600::/24fceb:56ff:ffff:ffff:ffff:ffff:ffff:ffff
88fceb:5700::/24fceb:57ff:ffff:ffff:ffff:ffff:ffff:ffff
89fceb:5800::/24fceb:58ff:ffff:ffff:ffff:ffff:ffff:ffff
90fceb:5900::/24fceb:59ff:ffff:ffff:ffff:ffff:ffff:ffff
91fceb:5a00::/24fceb:5aff:ffff:ffff:ffff:ffff:ffff:ffff
92fceb:5b00::/24fceb:5bff:ffff:ffff:ffff:ffff:ffff:ffff
93fceb:5c00::/24fceb:5cff:ffff:ffff:ffff:ffff:ffff:ffff
94fceb:5d00::/24fceb:5dff:ffff:ffff:ffff:ffff:ffff:ffff
95fceb:5e00::/24fceb:5eff:ffff:ffff:ffff:ffff:ffff:ffff
96fceb:5f00::/24fceb:5fff:ffff:ffff:ffff:ffff:ffff:ffff
97fceb:6000::/24fceb:60ff:ffff:ffff:ffff:ffff:ffff:ffff
98fceb:6100::/24fceb:61ff:ffff:ffff:ffff:ffff:ffff:ffff
99fceb:6200::/24fceb:62ff:ffff:ffff:ffff:ffff:ffff:ffff
100fceb:6300::/24fceb:63ff:ffff:ffff:ffff:ffff:ffff:ffff
101fceb:6400::/24fceb:64ff:ffff:ffff:ffff:ffff:ffff:ffff
102fceb:6500::/24fceb:65ff:ffff:ffff:ffff:ffff:ffff:ffff
103fceb:6600::/24fceb:66ff:ffff:ffff:ffff:ffff:ffff:ffff
104fceb:6700::/24fceb:67ff:ffff:ffff:ffff:ffff:ffff:ffff
105fceb:6800::/24fceb:68ff:ffff:ffff:ffff:ffff:ffff:ffff
106fceb:6900::/24fceb:69ff:ffff:ffff:ffff:ffff:ffff:ffff
107fceb:6a00::/24fceb:6aff:ffff:ffff:ffff:ffff:ffff:ffff
108fceb:6b00::/24fceb:6bff:ffff:ffff:ffff:ffff:ffff:ffff
109fceb:6c00::/24fceb:6cff:ffff:ffff:ffff:ffff:ffff:ffff
110fceb:6d00::/24fceb:6dff:ffff:ffff:ffff:ffff:ffff:ffff
111fceb:6e00::/24fceb:6eff:ffff:ffff:ffff:ffff:ffff:ffff
112fceb:6f00::/24fceb:6fff:ffff:ffff:ffff:ffff:ffff:ffff
113fceb:7000::/24fceb:70ff:ffff:ffff:ffff:ffff:ffff:ffff
114fceb:7100::/24fceb:71ff:ffff:ffff:ffff:ffff:ffff:ffff
115fceb:7200::/24fceb:72ff:ffff:ffff:ffff:ffff:ffff:ffff
116fceb:7300::/24fceb:73ff:ffff:ffff:ffff:ffff:ffff:ffff
117fceb:7400::/24fceb:74ff:ffff:ffff:ffff:ffff:ffff:ffff
118fceb:7500::/24fceb:75ff:ffff:ffff:ffff:ffff:ffff:ffff
119fceb:7600::/24fceb:76ff:ffff:ffff:ffff:ffff:ffff:ffff
120fceb:7700::/24fceb:77ff:ffff:ffff:ffff:ffff:ffff:ffff
121fceb:7800::/24fceb:78ff:ffff:ffff:ffff:ffff:ffff:ffff
122fceb:7900::/24fceb:79ff:ffff:ffff:ffff:ffff:ffff:ffff
123fceb:7a00::/24fceb:7aff:ffff:ffff:ffff:ffff:ffff:ffff
124fceb:7b00::/24fceb:7bff:ffff:ffff:ffff:ffff:ffff:ffff
125fceb:7c00::/24fceb:7cff:ffff:ffff:ffff:ffff:ffff:ffff
126fceb:7d00::/24fceb:7dff:ffff:ffff:ffff:ffff:ffff:ffff
127fceb:7e00::/24fceb:7eff:ffff:ffff:ffff:ffff:ffff:ffff
128fceb:7f00::/24fceb:7fff:ffff:ffff:ffff:ffff:ffff:ffff
129fceb:8000::/24fceb:80ff:ffff:ffff:ffff:ffff:ffff:ffff
130fceb:8100::/24fceb:81ff:ffff:ffff:ffff:ffff:ffff:ffff
131fceb:8200::/24fceb:82ff:ffff:ffff:ffff:ffff:ffff:ffff
132fceb:8300::/24fceb:83ff:ffff:ffff:ffff:ffff:ffff:ffff
133fceb:8400::/24fceb:84ff:ffff:ffff:ffff:ffff:ffff:ffff
134fceb:8500::/24fceb:85ff:ffff:ffff:ffff:ffff:ffff:ffff
135fceb:8600::/24fceb:86ff:ffff:ffff:ffff:ffff:ffff:ffff
136fceb:8700::/24fceb:87ff:ffff:ffff:ffff:ffff:ffff:ffff
137fceb:8800::/24fceb:88ff:ffff:ffff:ffff:ffff:ffff:ffff
138fceb:8900::/24fceb:89ff:ffff:ffff:ffff:ffff:ffff:ffff
139fceb:8a00::/24fceb:8aff:ffff:ffff:ffff:ffff:ffff:ffff
140fceb:8b00::/24fceb:8bff:ffff:ffff:ffff:ffff:ffff:ffff
141fceb:8c00::/24fceb:8cff:ffff:ffff:ffff:ffff:ffff:ffff
142fceb:8d00::/24fceb:8dff:ffff:ffff:ffff:ffff:ffff:ffff
143fceb:8e00::/24fceb:8eff:ffff:ffff:ffff:ffff:ffff:ffff
144fceb:8f00::/24fceb:8fff:ffff:ffff:ffff:ffff:ffff:ffff
145fceb:9000::/24fceb:90ff:ffff:ffff:ffff:ffff:ffff:ffff
146fceb:9100::/24fceb:91ff:ffff:ffff:ffff:ffff:ffff:ffff
147fceb:9200::/24fceb:92ff:ffff:ffff:ffff:ffff:ffff:ffff
148fceb:9300::/24fceb:93ff:ffff:ffff:ffff:ffff:ffff:ffff
149fceb:9400::/24fceb:94ff:ffff:ffff:ffff:ffff:ffff:ffff
150fceb:9500::/24fceb:95ff:ffff:ffff:ffff:ffff:ffff:ffff
151fceb:9600::/24fceb:96ff:ffff:ffff:ffff:ffff:ffff:ffff
152fceb:9700::/24fceb:97ff:ffff:ffff:ffff:ffff:ffff:ffff
153fceb:9800::/24fceb:98ff:ffff:ffff:ffff:ffff:ffff:ffff
154fceb:9900::/24fceb:99ff:ffff:ffff:ffff:ffff:ffff:ffff
155fceb:9a00::/24fceb:9aff:ffff:ffff:ffff:ffff:ffff:ffff
156fceb:9b00::/24fceb:9bff:ffff:ffff:ffff:ffff:ffff:ffff
157fceb:9c00::/24fceb:9cff:ffff:ffff:ffff:ffff:ffff:ffff
158fceb:9d00::/24fceb:9dff:ffff:ffff:ffff:ffff:ffff:ffff
159fceb:9e00::/24fceb:9eff:ffff:ffff:ffff:ffff:ffff:ffff
160fceb:9f00::/24fceb:9fff:ffff:ffff:ffff:ffff:ffff:ffff
161fceb:a000::/24fceb:a0ff:ffff:ffff:ffff:ffff:ffff:ffff
162fceb:a100::/24fceb:a1ff:ffff:ffff:ffff:ffff:ffff:ffff
163fceb:a200::/24fceb:a2ff:ffff:ffff:ffff:ffff:ffff:ffff
164fceb:a300::/24fceb:a3ff:ffff:ffff:ffff:ffff:ffff:ffff
165fceb:a400::/24fceb:a4ff:ffff:ffff:ffff:ffff:ffff:ffff
166fceb:a500::/24fceb:a5ff:ffff:ffff:ffff:ffff:ffff:ffff
167fceb:a600::/24fceb:a6ff:ffff:ffff:ffff:ffff:ffff:ffff
168fceb:a700::/24fceb:a7ff:ffff:ffff:ffff:ffff:ffff:ffff
169fceb:a800::/24fceb:a8ff:ffff:ffff:ffff:ffff:ffff:ffff
170fceb:a900::/24fceb:a9ff:ffff:ffff:ffff:ffff:ffff:ffff
171fceb:aa00::/24fceb:aaff:ffff:ffff:ffff:ffff:ffff:ffff
172fceb:ab00::/24fceb:abff:ffff:ffff:ffff:ffff:ffff:ffff
173fceb:ac00::/24fceb:acff:ffff:ffff:ffff:ffff:ffff:ffff
174fceb:ad00::/24fceb:adff:ffff:ffff:ffff:ffff:ffff:ffff
175fceb:ae00::/24fceb:aeff:ffff:ffff:ffff:ffff:ffff:ffff
176fceb:af00::/24fceb:afff:ffff:ffff:ffff:ffff:ffff:ffff
177fceb:b000::/24fceb:b0ff:ffff:ffff:ffff:ffff:ffff:ffff
178fceb:b100::/24fceb:b1ff:ffff:ffff:ffff:ffff:ffff:ffff
179fceb:b200::/24fceb:b2ff:ffff:ffff:ffff:ffff:ffff:ffff
180fceb:b300::/24fceb:b3ff:ffff:ffff:ffff:ffff:ffff:ffff
181fceb:b400::/24fceb:b4ff:ffff:ffff:ffff:ffff:ffff:ffff
182fceb:b500::/24fceb:b5ff:ffff:ffff:ffff:ffff:ffff:ffff
183fceb:b600::/24fceb:b6ff:ffff:ffff:ffff:ffff:ffff:ffff
184fceb:b700::/24fceb:b7ff:ffff:ffff:ffff:ffff:ffff:ffff
185fceb:b800::/24fceb:b8ff:ffff:ffff:ffff:ffff:ffff:ffff
186fceb:b900::/24fceb:b9ff:ffff:ffff:ffff:ffff:ffff:ffff
187fceb:ba00::/24fceb:baff:ffff:ffff:ffff:ffff:ffff:ffff
188fceb:bb00::/24fceb:bbff:ffff:ffff:ffff:ffff:ffff:ffff
189fceb:bc00::/24fceb:bcff:ffff:ffff:ffff:ffff:ffff:ffff
190fceb:bd00::/24fceb:bdff:ffff:ffff:ffff:ffff:ffff:ffff
191fceb:be00::/24fceb:beff:ffff:ffff:ffff:ffff:ffff:ffff
192fceb:bf00::/24fceb:bfff:ffff:ffff:ffff:ffff:ffff:ffff
193fceb:c000::/24fceb:c0ff:ffff:ffff:ffff:ffff:ffff:ffff
194fceb:c100::/24fceb:c1ff:ffff:ffff:ffff:ffff:ffff:ffff
195fceb:c200::/24fceb:c2ff:ffff:ffff:ffff:ffff:ffff:ffff
196fceb:c300::/24fceb:c3ff:ffff:ffff:ffff:ffff:ffff:ffff
197fceb:c400::/24fceb:c4ff:ffff:ffff:ffff:ffff:ffff:ffff
198fceb:c500::/24fceb:c5ff:ffff:ffff:ffff:ffff:ffff:ffff
199fceb:c600::/24fceb:c6ff:ffff:ffff:ffff:ffff:ffff:ffff
200fceb:c700::/24fceb:c7ff:ffff:ffff:ffff:ffff:ffff:ffff
201fceb:c800::/24fceb:c8ff:ffff:ffff:ffff:ffff:ffff:ffff
202fceb:c900::/24fceb:c9ff:ffff:ffff:ffff:ffff:ffff:ffff
203fceb:ca00::/24fceb:caff:ffff:ffff:ffff:ffff:ffff:ffff
204fceb:cb00::/24fceb:cbff:ffff:ffff:ffff:ffff:ffff:ffff
205fceb:cc00::/24fceb:ccff:ffff:ffff:ffff:ffff:ffff:ffff
206fceb:cd00::/24fceb:cdff:ffff:ffff:ffff:ffff:ffff:ffff
207fceb:ce00::/24fceb:ceff:ffff:ffff:ffff:ffff:ffff:ffff
208fceb:cf00::/24fceb:cfff:ffff:ffff:ffff:ffff:ffff:ffff
209fceb:d000::/24fceb:d0ff:ffff:ffff:ffff:ffff:ffff:ffff
210fceb:d100::/24fceb:d1ff:ffff:ffff:ffff:ffff:ffff:ffff
211fceb:d200::/24fceb:d2ff:ffff:ffff:ffff:ffff:ffff:ffff
212fceb:d300::/24fceb:d3ff:ffff:ffff:ffff:ffff:ffff:ffff
213fceb:d400::/24fceb:d4ff:ffff:ffff:ffff:ffff:ffff:ffff
214fceb:d500::/24fceb:d5ff:ffff:ffff:ffff:ffff:ffff:ffff
215fceb:d600::/24fceb:d6ff:ffff:ffff:ffff:ffff:ffff:ffff
216fceb:d700::/24fceb:d7ff:ffff:ffff:ffff:ffff:ffff:ffff
217fceb:d800::/24fceb:d8ff:ffff:ffff:ffff:ffff:ffff:ffff
218fceb:d900::/24fceb:d9ff:ffff:ffff:ffff:ffff:ffff:ffff
219fceb:da00::/24fceb:daff:ffff:ffff:ffff:ffff:ffff:ffff
220fceb:db00::/24fceb:dbff:ffff:ffff:ffff:ffff:ffff:ffff
221fceb:dc00::/24fceb:dcff:ffff:ffff:ffff:ffff:ffff:ffff
222fceb:dd00::/24fceb:ddff:ffff:ffff:ffff:ffff:ffff:ffff
223fceb:de00::/24fceb:deff:ffff:ffff:ffff:ffff:ffff:ffff
224fceb:df00::/24fceb:dfff:ffff:ffff:ffff:ffff:ffff:ffff
225fceb:e000::/24fceb:e0ff:ffff:ffff:ffff:ffff:ffff:ffff
226fceb:e100::/24fceb:e1ff:ffff:ffff:ffff:ffff:ffff:ffff
227fceb:e200::/24fceb:e2ff:ffff:ffff:ffff:ffff:ffff:ffff
228fceb:e300::/24fceb:e3ff:ffff:ffff:ffff:ffff:ffff:ffff
229fceb:e400::/24fceb:e4ff:ffff:ffff:ffff:ffff:ffff:ffff
230fceb:e500::/24fceb:e5ff:ffff:ffff:ffff:ffff:ffff:ffff
231fceb:e600::/24fceb:e6ff:ffff:ffff:ffff:ffff:ffff:ffff
232fceb:e700::/24fceb:e7ff:ffff:ffff:ffff:ffff:ffff:ffff
233fceb:e800::/24fceb:e8ff:ffff:ffff:ffff:ffff:ffff:ffff
234fceb:e900::/24fceb:e9ff:ffff:ffff:ffff:ffff:ffff:ffff
235fceb:ea00::/24fceb:eaff:ffff:ffff:ffff:ffff:ffff:ffff
236fceb:eb00::/24fceb:ebff:ffff:ffff:ffff:ffff:ffff:ffff
237fceb:ec00::/24fceb:ecff:ffff:ffff:ffff:ffff:ffff:ffff
238fceb:ed00::/24fceb:edff:ffff:ffff:ffff:ffff:ffff:ffff
239fceb:ee00::/24fceb:eeff:ffff:ffff:ffff:ffff:ffff:ffff
240fceb:ef00::/24fceb:efff:ffff:ffff:ffff:ffff:ffff:ffff
241fceb:f000::/24fceb:f0ff:ffff:ffff:ffff:ffff:ffff:ffff
242fceb:f100::/24fceb:f1ff:ffff:ffff:ffff:ffff:ffff:ffff
243fceb:f200::/24fceb:f2ff:ffff:ffff:ffff:ffff:ffff:ffff
244fceb:f300::/24fceb:f3ff:ffff:ffff:ffff:ffff:ffff:ffff
245fceb:f400::/24fceb:f4ff:ffff:ffff:ffff:ffff:ffff:ffff
246fceb:f500::/24fceb:f5ff:ffff:ffff:ffff:ffff:ffff:ffff
247fceb:f600::/24fceb:f6ff:ffff:ffff:ffff:ffff:ffff:ffff
248fceb:f700::/24fceb:f7ff:ffff:ffff:ffff:ffff:ffff:ffff
249fceb:f800::/24fceb:f8ff:ffff:ffff:ffff:ffff:ffff:ffff
250fceb:f900::/24fceb:f9ff:ffff:ffff:ffff:ffff:ffff:ffff
251fceb:fa00::/24fceb:faff:ffff:ffff:ffff:ffff:ffff:ffff
252fceb:fb00::/24fceb:fbff:ffff:ffff:ffff:ffff:ffff:ffff
253fceb:fc00::/24fceb:fcff:ffff:ffff:ffff:ffff:ffff:ffff
254fceb:fd00::/24fceb:fdff:ffff:ffff:ffff:ffff:ffff:ffff
255fceb:fe00::/24fceb:feff:ffff:ffff:ffff:ffff:ffff:ffff
256fceb:ff00::/24fceb:ffff: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.