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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
ff6a::/16
First address
ff6a::
Last address
ff6a: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
ff6a:0000:0000:0000:0000:0000:0000:0000
Type
Multicast ff00::/8
One-to-many traffic; replaces broadcast
Reverse DNS zone
a.6.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)

ff6a::/16 makes 256 subnets of /24.

Subnets
#SubnetLast address
1ff6a::/24ff6a:ff:ffff:ffff:ffff:ffff:ffff:ffff
2ff6a:100::/24ff6a:1ff:ffff:ffff:ffff:ffff:ffff:ffff
3ff6a:200::/24ff6a:2ff:ffff:ffff:ffff:ffff:ffff:ffff
4ff6a:300::/24ff6a:3ff:ffff:ffff:ffff:ffff:ffff:ffff
5ff6a:400::/24ff6a:4ff:ffff:ffff:ffff:ffff:ffff:ffff
6ff6a:500::/24ff6a:5ff:ffff:ffff:ffff:ffff:ffff:ffff
7ff6a:600::/24ff6a:6ff:ffff:ffff:ffff:ffff:ffff:ffff
8ff6a:700::/24ff6a:7ff:ffff:ffff:ffff:ffff:ffff:ffff
9ff6a:800::/24ff6a:8ff:ffff:ffff:ffff:ffff:ffff:ffff
10ff6a:900::/24ff6a:9ff:ffff:ffff:ffff:ffff:ffff:ffff
11ff6a:a00::/24ff6a:aff:ffff:ffff:ffff:ffff:ffff:ffff
12ff6a:b00::/24ff6a:bff:ffff:ffff:ffff:ffff:ffff:ffff
13ff6a:c00::/24ff6a:cff:ffff:ffff:ffff:ffff:ffff:ffff
14ff6a:d00::/24ff6a:dff:ffff:ffff:ffff:ffff:ffff:ffff
15ff6a:e00::/24ff6a:eff:ffff:ffff:ffff:ffff:ffff:ffff
16ff6a:f00::/24ff6a:fff:ffff:ffff:ffff:ffff:ffff:ffff
17ff6a:1000::/24ff6a:10ff:ffff:ffff:ffff:ffff:ffff:ffff
18ff6a:1100::/24ff6a:11ff:ffff:ffff:ffff:ffff:ffff:ffff
19ff6a:1200::/24ff6a:12ff:ffff:ffff:ffff:ffff:ffff:ffff
20ff6a:1300::/24ff6a:13ff:ffff:ffff:ffff:ffff:ffff:ffff
21ff6a:1400::/24ff6a:14ff:ffff:ffff:ffff:ffff:ffff:ffff
22ff6a:1500::/24ff6a:15ff:ffff:ffff:ffff:ffff:ffff:ffff
23ff6a:1600::/24ff6a:16ff:ffff:ffff:ffff:ffff:ffff:ffff
24ff6a:1700::/24ff6a:17ff:ffff:ffff:ffff:ffff:ffff:ffff
25ff6a:1800::/24ff6a:18ff:ffff:ffff:ffff:ffff:ffff:ffff
26ff6a:1900::/24ff6a:19ff:ffff:ffff:ffff:ffff:ffff:ffff
27ff6a:1a00::/24ff6a:1aff:ffff:ffff:ffff:ffff:ffff:ffff
28ff6a:1b00::/24ff6a:1bff:ffff:ffff:ffff:ffff:ffff:ffff
29ff6a:1c00::/24ff6a:1cff:ffff:ffff:ffff:ffff:ffff:ffff
30ff6a:1d00::/24ff6a:1dff:ffff:ffff:ffff:ffff:ffff:ffff
31ff6a:1e00::/24ff6a:1eff:ffff:ffff:ffff:ffff:ffff:ffff
32ff6a:1f00::/24ff6a:1fff:ffff:ffff:ffff:ffff:ffff:ffff
33ff6a:2000::/24ff6a:20ff:ffff:ffff:ffff:ffff:ffff:ffff
34ff6a:2100::/24ff6a:21ff:ffff:ffff:ffff:ffff:ffff:ffff
35ff6a:2200::/24ff6a:22ff:ffff:ffff:ffff:ffff:ffff:ffff
36ff6a:2300::/24ff6a:23ff:ffff:ffff:ffff:ffff:ffff:ffff
37ff6a:2400::/24ff6a:24ff:ffff:ffff:ffff:ffff:ffff:ffff
38ff6a:2500::/24ff6a:25ff:ffff:ffff:ffff:ffff:ffff:ffff
39ff6a:2600::/24ff6a:26ff:ffff:ffff:ffff:ffff:ffff:ffff
40ff6a:2700::/24ff6a:27ff:ffff:ffff:ffff:ffff:ffff:ffff
41ff6a:2800::/24ff6a:28ff:ffff:ffff:ffff:ffff:ffff:ffff
42ff6a:2900::/24ff6a:29ff:ffff:ffff:ffff:ffff:ffff:ffff
43ff6a:2a00::/24ff6a:2aff:ffff:ffff:ffff:ffff:ffff:ffff
44ff6a:2b00::/24ff6a:2bff:ffff:ffff:ffff:ffff:ffff:ffff
45ff6a:2c00::/24ff6a:2cff:ffff:ffff:ffff:ffff:ffff:ffff
46ff6a:2d00::/24ff6a:2dff:ffff:ffff:ffff:ffff:ffff:ffff
47ff6a:2e00::/24ff6a:2eff:ffff:ffff:ffff:ffff:ffff:ffff
48ff6a:2f00::/24ff6a:2fff:ffff:ffff:ffff:ffff:ffff:ffff
49ff6a:3000::/24ff6a:30ff:ffff:ffff:ffff:ffff:ffff:ffff
50ff6a:3100::/24ff6a:31ff:ffff:ffff:ffff:ffff:ffff:ffff
51ff6a:3200::/24ff6a:32ff:ffff:ffff:ffff:ffff:ffff:ffff
52ff6a:3300::/24ff6a:33ff:ffff:ffff:ffff:ffff:ffff:ffff
53ff6a:3400::/24ff6a:34ff:ffff:ffff:ffff:ffff:ffff:ffff
54ff6a:3500::/24ff6a:35ff:ffff:ffff:ffff:ffff:ffff:ffff
55ff6a:3600::/24ff6a:36ff:ffff:ffff:ffff:ffff:ffff:ffff
56ff6a:3700::/24ff6a:37ff:ffff:ffff:ffff:ffff:ffff:ffff
57ff6a:3800::/24ff6a:38ff:ffff:ffff:ffff:ffff:ffff:ffff
58ff6a:3900::/24ff6a:39ff:ffff:ffff:ffff:ffff:ffff:ffff
59ff6a:3a00::/24ff6a:3aff:ffff:ffff:ffff:ffff:ffff:ffff
60ff6a:3b00::/24ff6a:3bff:ffff:ffff:ffff:ffff:ffff:ffff
61ff6a:3c00::/24ff6a:3cff:ffff:ffff:ffff:ffff:ffff:ffff
62ff6a:3d00::/24ff6a:3dff:ffff:ffff:ffff:ffff:ffff:ffff
63ff6a:3e00::/24ff6a:3eff:ffff:ffff:ffff:ffff:ffff:ffff
64ff6a:3f00::/24ff6a:3fff:ffff:ffff:ffff:ffff:ffff:ffff
65ff6a:4000::/24ff6a:40ff:ffff:ffff:ffff:ffff:ffff:ffff
66ff6a:4100::/24ff6a:41ff:ffff:ffff:ffff:ffff:ffff:ffff
67ff6a:4200::/24ff6a:42ff:ffff:ffff:ffff:ffff:ffff:ffff
68ff6a:4300::/24ff6a:43ff:ffff:ffff:ffff:ffff:ffff:ffff
69ff6a:4400::/24ff6a:44ff:ffff:ffff:ffff:ffff:ffff:ffff
70ff6a:4500::/24ff6a:45ff:ffff:ffff:ffff:ffff:ffff:ffff
71ff6a:4600::/24ff6a:46ff:ffff:ffff:ffff:ffff:ffff:ffff
72ff6a:4700::/24ff6a:47ff:ffff:ffff:ffff:ffff:ffff:ffff
73ff6a:4800::/24ff6a:48ff:ffff:ffff:ffff:ffff:ffff:ffff
74ff6a:4900::/24ff6a:49ff:ffff:ffff:ffff:ffff:ffff:ffff
75ff6a:4a00::/24ff6a:4aff:ffff:ffff:ffff:ffff:ffff:ffff
76ff6a:4b00::/24ff6a:4bff:ffff:ffff:ffff:ffff:ffff:ffff
77ff6a:4c00::/24ff6a:4cff:ffff:ffff:ffff:ffff:ffff:ffff
78ff6a:4d00::/24ff6a:4dff:ffff:ffff:ffff:ffff:ffff:ffff
79ff6a:4e00::/24ff6a:4eff:ffff:ffff:ffff:ffff:ffff:ffff
80ff6a:4f00::/24ff6a:4fff:ffff:ffff:ffff:ffff:ffff:ffff
81ff6a:5000::/24ff6a:50ff:ffff:ffff:ffff:ffff:ffff:ffff
82ff6a:5100::/24ff6a:51ff:ffff:ffff:ffff:ffff:ffff:ffff
83ff6a:5200::/24ff6a:52ff:ffff:ffff:ffff:ffff:ffff:ffff
84ff6a:5300::/24ff6a:53ff:ffff:ffff:ffff:ffff:ffff:ffff
85ff6a:5400::/24ff6a:54ff:ffff:ffff:ffff:ffff:ffff:ffff
86ff6a:5500::/24ff6a:55ff:ffff:ffff:ffff:ffff:ffff:ffff
87ff6a:5600::/24ff6a:56ff:ffff:ffff:ffff:ffff:ffff:ffff
88ff6a:5700::/24ff6a:57ff:ffff:ffff:ffff:ffff:ffff:ffff
89ff6a:5800::/24ff6a:58ff:ffff:ffff:ffff:ffff:ffff:ffff
90ff6a:5900::/24ff6a:59ff:ffff:ffff:ffff:ffff:ffff:ffff
91ff6a:5a00::/24ff6a:5aff:ffff:ffff:ffff:ffff:ffff:ffff
92ff6a:5b00::/24ff6a:5bff:ffff:ffff:ffff:ffff:ffff:ffff
93ff6a:5c00::/24ff6a:5cff:ffff:ffff:ffff:ffff:ffff:ffff
94ff6a:5d00::/24ff6a:5dff:ffff:ffff:ffff:ffff:ffff:ffff
95ff6a:5e00::/24ff6a:5eff:ffff:ffff:ffff:ffff:ffff:ffff
96ff6a:5f00::/24ff6a:5fff:ffff:ffff:ffff:ffff:ffff:ffff
97ff6a:6000::/24ff6a:60ff:ffff:ffff:ffff:ffff:ffff:ffff
98ff6a:6100::/24ff6a:61ff:ffff:ffff:ffff:ffff:ffff:ffff
99ff6a:6200::/24ff6a:62ff:ffff:ffff:ffff:ffff:ffff:ffff
100ff6a:6300::/24ff6a:63ff:ffff:ffff:ffff:ffff:ffff:ffff
101ff6a:6400::/24ff6a:64ff:ffff:ffff:ffff:ffff:ffff:ffff
102ff6a:6500::/24ff6a:65ff:ffff:ffff:ffff:ffff:ffff:ffff
103ff6a:6600::/24ff6a:66ff:ffff:ffff:ffff:ffff:ffff:ffff
104ff6a:6700::/24ff6a:67ff:ffff:ffff:ffff:ffff:ffff:ffff
105ff6a:6800::/24ff6a:68ff:ffff:ffff:ffff:ffff:ffff:ffff
106ff6a:6900::/24ff6a:69ff:ffff:ffff:ffff:ffff:ffff:ffff
107ff6a:6a00::/24ff6a:6aff:ffff:ffff:ffff:ffff:ffff:ffff
108ff6a:6b00::/24ff6a:6bff:ffff:ffff:ffff:ffff:ffff:ffff
109ff6a:6c00::/24ff6a:6cff:ffff:ffff:ffff:ffff:ffff:ffff
110ff6a:6d00::/24ff6a:6dff:ffff:ffff:ffff:ffff:ffff:ffff
111ff6a:6e00::/24ff6a:6eff:ffff:ffff:ffff:ffff:ffff:ffff
112ff6a:6f00::/24ff6a:6fff:ffff:ffff:ffff:ffff:ffff:ffff
113ff6a:7000::/24ff6a:70ff:ffff:ffff:ffff:ffff:ffff:ffff
114ff6a:7100::/24ff6a:71ff:ffff:ffff:ffff:ffff:ffff:ffff
115ff6a:7200::/24ff6a:72ff:ffff:ffff:ffff:ffff:ffff:ffff
116ff6a:7300::/24ff6a:73ff:ffff:ffff:ffff:ffff:ffff:ffff
117ff6a:7400::/24ff6a:74ff:ffff:ffff:ffff:ffff:ffff:ffff
118ff6a:7500::/24ff6a:75ff:ffff:ffff:ffff:ffff:ffff:ffff
119ff6a:7600::/24ff6a:76ff:ffff:ffff:ffff:ffff:ffff:ffff
120ff6a:7700::/24ff6a:77ff:ffff:ffff:ffff:ffff:ffff:ffff
121ff6a:7800::/24ff6a:78ff:ffff:ffff:ffff:ffff:ffff:ffff
122ff6a:7900::/24ff6a:79ff:ffff:ffff:ffff:ffff:ffff:ffff
123ff6a:7a00::/24ff6a:7aff:ffff:ffff:ffff:ffff:ffff:ffff
124ff6a:7b00::/24ff6a:7bff:ffff:ffff:ffff:ffff:ffff:ffff
125ff6a:7c00::/24ff6a:7cff:ffff:ffff:ffff:ffff:ffff:ffff
126ff6a:7d00::/24ff6a:7dff:ffff:ffff:ffff:ffff:ffff:ffff
127ff6a:7e00::/24ff6a:7eff:ffff:ffff:ffff:ffff:ffff:ffff
128ff6a:7f00::/24ff6a:7fff:ffff:ffff:ffff:ffff:ffff:ffff
129ff6a:8000::/24ff6a:80ff:ffff:ffff:ffff:ffff:ffff:ffff
130ff6a:8100::/24ff6a:81ff:ffff:ffff:ffff:ffff:ffff:ffff
131ff6a:8200::/24ff6a:82ff:ffff:ffff:ffff:ffff:ffff:ffff
132ff6a:8300::/24ff6a:83ff:ffff:ffff:ffff:ffff:ffff:ffff
133ff6a:8400::/24ff6a:84ff:ffff:ffff:ffff:ffff:ffff:ffff
134ff6a:8500::/24ff6a:85ff:ffff:ffff:ffff:ffff:ffff:ffff
135ff6a:8600::/24ff6a:86ff:ffff:ffff:ffff:ffff:ffff:ffff
136ff6a:8700::/24ff6a:87ff:ffff:ffff:ffff:ffff:ffff:ffff
137ff6a:8800::/24ff6a:88ff:ffff:ffff:ffff:ffff:ffff:ffff
138ff6a:8900::/24ff6a:89ff:ffff:ffff:ffff:ffff:ffff:ffff
139ff6a:8a00::/24ff6a:8aff:ffff:ffff:ffff:ffff:ffff:ffff
140ff6a:8b00::/24ff6a:8bff:ffff:ffff:ffff:ffff:ffff:ffff
141ff6a:8c00::/24ff6a:8cff:ffff:ffff:ffff:ffff:ffff:ffff
142ff6a:8d00::/24ff6a:8dff:ffff:ffff:ffff:ffff:ffff:ffff
143ff6a:8e00::/24ff6a:8eff:ffff:ffff:ffff:ffff:ffff:ffff
144ff6a:8f00::/24ff6a:8fff:ffff:ffff:ffff:ffff:ffff:ffff
145ff6a:9000::/24ff6a:90ff:ffff:ffff:ffff:ffff:ffff:ffff
146ff6a:9100::/24ff6a:91ff:ffff:ffff:ffff:ffff:ffff:ffff
147ff6a:9200::/24ff6a:92ff:ffff:ffff:ffff:ffff:ffff:ffff
148ff6a:9300::/24ff6a:93ff:ffff:ffff:ffff:ffff:ffff:ffff
149ff6a:9400::/24ff6a:94ff:ffff:ffff:ffff:ffff:ffff:ffff
150ff6a:9500::/24ff6a:95ff:ffff:ffff:ffff:ffff:ffff:ffff
151ff6a:9600::/24ff6a:96ff:ffff:ffff:ffff:ffff:ffff:ffff
152ff6a:9700::/24ff6a:97ff:ffff:ffff:ffff:ffff:ffff:ffff
153ff6a:9800::/24ff6a:98ff:ffff:ffff:ffff:ffff:ffff:ffff
154ff6a:9900::/24ff6a:99ff:ffff:ffff:ffff:ffff:ffff:ffff
155ff6a:9a00::/24ff6a:9aff:ffff:ffff:ffff:ffff:ffff:ffff
156ff6a:9b00::/24ff6a:9bff:ffff:ffff:ffff:ffff:ffff:ffff
157ff6a:9c00::/24ff6a:9cff:ffff:ffff:ffff:ffff:ffff:ffff
158ff6a:9d00::/24ff6a:9dff:ffff:ffff:ffff:ffff:ffff:ffff
159ff6a:9e00::/24ff6a:9eff:ffff:ffff:ffff:ffff:ffff:ffff
160ff6a:9f00::/24ff6a:9fff:ffff:ffff:ffff:ffff:ffff:ffff
161ff6a:a000::/24ff6a:a0ff:ffff:ffff:ffff:ffff:ffff:ffff
162ff6a:a100::/24ff6a:a1ff:ffff:ffff:ffff:ffff:ffff:ffff
163ff6a:a200::/24ff6a:a2ff:ffff:ffff:ffff:ffff:ffff:ffff
164ff6a:a300::/24ff6a:a3ff:ffff:ffff:ffff:ffff:ffff:ffff
165ff6a:a400::/24ff6a:a4ff:ffff:ffff:ffff:ffff:ffff:ffff
166ff6a:a500::/24ff6a:a5ff:ffff:ffff:ffff:ffff:ffff:ffff
167ff6a:a600::/24ff6a:a6ff:ffff:ffff:ffff:ffff:ffff:ffff
168ff6a:a700::/24ff6a:a7ff:ffff:ffff:ffff:ffff:ffff:ffff
169ff6a:a800::/24ff6a:a8ff:ffff:ffff:ffff:ffff:ffff:ffff
170ff6a:a900::/24ff6a:a9ff:ffff:ffff:ffff:ffff:ffff:ffff
171ff6a:aa00::/24ff6a:aaff:ffff:ffff:ffff:ffff:ffff:ffff
172ff6a:ab00::/24ff6a:abff:ffff:ffff:ffff:ffff:ffff:ffff
173ff6a:ac00::/24ff6a:acff:ffff:ffff:ffff:ffff:ffff:ffff
174ff6a:ad00::/24ff6a:adff:ffff:ffff:ffff:ffff:ffff:ffff
175ff6a:ae00::/24ff6a:aeff:ffff:ffff:ffff:ffff:ffff:ffff
176ff6a:af00::/24ff6a:afff:ffff:ffff:ffff:ffff:ffff:ffff
177ff6a:b000::/24ff6a:b0ff:ffff:ffff:ffff:ffff:ffff:ffff
178ff6a:b100::/24ff6a:b1ff:ffff:ffff:ffff:ffff:ffff:ffff
179ff6a:b200::/24ff6a:b2ff:ffff:ffff:ffff:ffff:ffff:ffff
180ff6a:b300::/24ff6a:b3ff:ffff:ffff:ffff:ffff:ffff:ffff
181ff6a:b400::/24ff6a:b4ff:ffff:ffff:ffff:ffff:ffff:ffff
182ff6a:b500::/24ff6a:b5ff:ffff:ffff:ffff:ffff:ffff:ffff
183ff6a:b600::/24ff6a:b6ff:ffff:ffff:ffff:ffff:ffff:ffff
184ff6a:b700::/24ff6a:b7ff:ffff:ffff:ffff:ffff:ffff:ffff
185ff6a:b800::/24ff6a:b8ff:ffff:ffff:ffff:ffff:ffff:ffff
186ff6a:b900::/24ff6a:b9ff:ffff:ffff:ffff:ffff:ffff:ffff
187ff6a:ba00::/24ff6a:baff:ffff:ffff:ffff:ffff:ffff:ffff
188ff6a:bb00::/24ff6a:bbff:ffff:ffff:ffff:ffff:ffff:ffff
189ff6a:bc00::/24ff6a:bcff:ffff:ffff:ffff:ffff:ffff:ffff
190ff6a:bd00::/24ff6a:bdff:ffff:ffff:ffff:ffff:ffff:ffff
191ff6a:be00::/24ff6a:beff:ffff:ffff:ffff:ffff:ffff:ffff
192ff6a:bf00::/24ff6a:bfff:ffff:ffff:ffff:ffff:ffff:ffff
193ff6a:c000::/24ff6a:c0ff:ffff:ffff:ffff:ffff:ffff:ffff
194ff6a:c100::/24ff6a:c1ff:ffff:ffff:ffff:ffff:ffff:ffff
195ff6a:c200::/24ff6a:c2ff:ffff:ffff:ffff:ffff:ffff:ffff
196ff6a:c300::/24ff6a:c3ff:ffff:ffff:ffff:ffff:ffff:ffff
197ff6a:c400::/24ff6a:c4ff:ffff:ffff:ffff:ffff:ffff:ffff
198ff6a:c500::/24ff6a:c5ff:ffff:ffff:ffff:ffff:ffff:ffff
199ff6a:c600::/24ff6a:c6ff:ffff:ffff:ffff:ffff:ffff:ffff
200ff6a:c700::/24ff6a:c7ff:ffff:ffff:ffff:ffff:ffff:ffff
201ff6a:c800::/24ff6a:c8ff:ffff:ffff:ffff:ffff:ffff:ffff
202ff6a:c900::/24ff6a:c9ff:ffff:ffff:ffff:ffff:ffff:ffff
203ff6a:ca00::/24ff6a:caff:ffff:ffff:ffff:ffff:ffff:ffff
204ff6a:cb00::/24ff6a:cbff:ffff:ffff:ffff:ffff:ffff:ffff
205ff6a:cc00::/24ff6a:ccff:ffff:ffff:ffff:ffff:ffff:ffff
206ff6a:cd00::/24ff6a:cdff:ffff:ffff:ffff:ffff:ffff:ffff
207ff6a:ce00::/24ff6a:ceff:ffff:ffff:ffff:ffff:ffff:ffff
208ff6a:cf00::/24ff6a:cfff:ffff:ffff:ffff:ffff:ffff:ffff
209ff6a:d000::/24ff6a:d0ff:ffff:ffff:ffff:ffff:ffff:ffff
210ff6a:d100::/24ff6a:d1ff:ffff:ffff:ffff:ffff:ffff:ffff
211ff6a:d200::/24ff6a:d2ff:ffff:ffff:ffff:ffff:ffff:ffff
212ff6a:d300::/24ff6a:d3ff:ffff:ffff:ffff:ffff:ffff:ffff
213ff6a:d400::/24ff6a:d4ff:ffff:ffff:ffff:ffff:ffff:ffff
214ff6a:d500::/24ff6a:d5ff:ffff:ffff:ffff:ffff:ffff:ffff
215ff6a:d600::/24ff6a:d6ff:ffff:ffff:ffff:ffff:ffff:ffff
216ff6a:d700::/24ff6a:d7ff:ffff:ffff:ffff:ffff:ffff:ffff
217ff6a:d800::/24ff6a:d8ff:ffff:ffff:ffff:ffff:ffff:ffff
218ff6a:d900::/24ff6a:d9ff:ffff:ffff:ffff:ffff:ffff:ffff
219ff6a:da00::/24ff6a:daff:ffff:ffff:ffff:ffff:ffff:ffff
220ff6a:db00::/24ff6a:dbff:ffff:ffff:ffff:ffff:ffff:ffff
221ff6a:dc00::/24ff6a:dcff:ffff:ffff:ffff:ffff:ffff:ffff
222ff6a:dd00::/24ff6a:ddff:ffff:ffff:ffff:ffff:ffff:ffff
223ff6a:de00::/24ff6a:deff:ffff:ffff:ffff:ffff:ffff:ffff
224ff6a:df00::/24ff6a:dfff:ffff:ffff:ffff:ffff:ffff:ffff
225ff6a:e000::/24ff6a:e0ff:ffff:ffff:ffff:ffff:ffff:ffff
226ff6a:e100::/24ff6a:e1ff:ffff:ffff:ffff:ffff:ffff:ffff
227ff6a:e200::/24ff6a:e2ff:ffff:ffff:ffff:ffff:ffff:ffff
228ff6a:e300::/24ff6a:e3ff:ffff:ffff:ffff:ffff:ffff:ffff
229ff6a:e400::/24ff6a:e4ff:ffff:ffff:ffff:ffff:ffff:ffff
230ff6a:e500::/24ff6a:e5ff:ffff:ffff:ffff:ffff:ffff:ffff
231ff6a:e600::/24ff6a:e6ff:ffff:ffff:ffff:ffff:ffff:ffff
232ff6a:e700::/24ff6a:e7ff:ffff:ffff:ffff:ffff:ffff:ffff
233ff6a:e800::/24ff6a:e8ff:ffff:ffff:ffff:ffff:ffff:ffff
234ff6a:e900::/24ff6a:e9ff:ffff:ffff:ffff:ffff:ffff:ffff
235ff6a:ea00::/24ff6a:eaff:ffff:ffff:ffff:ffff:ffff:ffff
236ff6a:eb00::/24ff6a:ebff:ffff:ffff:ffff:ffff:ffff:ffff
237ff6a:ec00::/24ff6a:ecff:ffff:ffff:ffff:ffff:ffff:ffff
238ff6a:ed00::/24ff6a:edff:ffff:ffff:ffff:ffff:ffff:ffff
239ff6a:ee00::/24ff6a:eeff:ffff:ffff:ffff:ffff:ffff:ffff
240ff6a:ef00::/24ff6a:efff:ffff:ffff:ffff:ffff:ffff:ffff
241ff6a:f000::/24ff6a:f0ff:ffff:ffff:ffff:ffff:ffff:ffff
242ff6a:f100::/24ff6a:f1ff:ffff:ffff:ffff:ffff:ffff:ffff
243ff6a:f200::/24ff6a:f2ff:ffff:ffff:ffff:ffff:ffff:ffff
244ff6a:f300::/24ff6a:f3ff:ffff:ffff:ffff:ffff:ffff:ffff
245ff6a:f400::/24ff6a:f4ff:ffff:ffff:ffff:ffff:ffff:ffff
246ff6a:f500::/24ff6a:f5ff:ffff:ffff:ffff:ffff:ffff:ffff
247ff6a:f600::/24ff6a:f6ff:ffff:ffff:ffff:ffff:ffff:ffff
248ff6a:f700::/24ff6a:f7ff:ffff:ffff:ffff:ffff:ffff:ffff
249ff6a:f800::/24ff6a:f8ff:ffff:ffff:ffff:ffff:ffff:ffff
250ff6a:f900::/24ff6a:f9ff:ffff:ffff:ffff:ffff:ffff:ffff
251ff6a:fa00::/24ff6a:faff:ffff:ffff:ffff:ffff:ffff:ffff
252ff6a:fb00::/24ff6a:fbff:ffff:ffff:ffff:ffff:ffff:ffff
253ff6a:fc00::/24ff6a:fcff:ffff:ffff:ffff:ffff:ffff:ffff
254ff6a:fd00::/24ff6a:fdff:ffff:ffff:ffff:ffff:ffff:ffff
255ff6a:fe00::/24ff6a:feff:ffff:ffff:ffff:ffff:ffff:ffff
256ff6a:ff00::/24ff6a: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.