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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
ffff::/16
First address
ffff::
Last address
ffff: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
ffff:0000:0000:0000:0000:0000:0000:0000
Type
Multicast ff00::/8
One-to-many traffic; replaces broadcast
Reverse DNS zone
f.f.f.f.ip6.arpa
Split into smaller subnets/24
/17 (2)/18 (4)/19 (8)/20 (16)/24 (256)/28 (4,096)/32 (65,536)

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

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