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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
ff2a::/16
First address
ff2a::
Last address
ff2a: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
ff2a:0000:0000:0000:0000:0000:0000:0000
Type
Multicast ff00::/8
One-to-many traffic; replaces broadcast
Reverse DNS zone
a.2.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)

ff2a::/16 makes 256 subnets of /24.

Subnets
#SubnetLast address
1ff2a::/24ff2a:ff:ffff:ffff:ffff:ffff:ffff:ffff
2ff2a:100::/24ff2a:1ff:ffff:ffff:ffff:ffff:ffff:ffff
3ff2a:200::/24ff2a:2ff:ffff:ffff:ffff:ffff:ffff:ffff
4ff2a:300::/24ff2a:3ff:ffff:ffff:ffff:ffff:ffff:ffff
5ff2a:400::/24ff2a:4ff:ffff:ffff:ffff:ffff:ffff:ffff
6ff2a:500::/24ff2a:5ff:ffff:ffff:ffff:ffff:ffff:ffff
7ff2a:600::/24ff2a:6ff:ffff:ffff:ffff:ffff:ffff:ffff
8ff2a:700::/24ff2a:7ff:ffff:ffff:ffff:ffff:ffff:ffff
9ff2a:800::/24ff2a:8ff:ffff:ffff:ffff:ffff:ffff:ffff
10ff2a:900::/24ff2a:9ff:ffff:ffff:ffff:ffff:ffff:ffff
11ff2a:a00::/24ff2a:aff:ffff:ffff:ffff:ffff:ffff:ffff
12ff2a:b00::/24ff2a:bff:ffff:ffff:ffff:ffff:ffff:ffff
13ff2a:c00::/24ff2a:cff:ffff:ffff:ffff:ffff:ffff:ffff
14ff2a:d00::/24ff2a:dff:ffff:ffff:ffff:ffff:ffff:ffff
15ff2a:e00::/24ff2a:eff:ffff:ffff:ffff:ffff:ffff:ffff
16ff2a:f00::/24ff2a:fff:ffff:ffff:ffff:ffff:ffff:ffff
17ff2a:1000::/24ff2a:10ff:ffff:ffff:ffff:ffff:ffff:ffff
18ff2a:1100::/24ff2a:11ff:ffff:ffff:ffff:ffff:ffff:ffff
19ff2a:1200::/24ff2a:12ff:ffff:ffff:ffff:ffff:ffff:ffff
20ff2a:1300::/24ff2a:13ff:ffff:ffff:ffff:ffff:ffff:ffff
21ff2a:1400::/24ff2a:14ff:ffff:ffff:ffff:ffff:ffff:ffff
22ff2a:1500::/24ff2a:15ff:ffff:ffff:ffff:ffff:ffff:ffff
23ff2a:1600::/24ff2a:16ff:ffff:ffff:ffff:ffff:ffff:ffff
24ff2a:1700::/24ff2a:17ff:ffff:ffff:ffff:ffff:ffff:ffff
25ff2a:1800::/24ff2a:18ff:ffff:ffff:ffff:ffff:ffff:ffff
26ff2a:1900::/24ff2a:19ff:ffff:ffff:ffff:ffff:ffff:ffff
27ff2a:1a00::/24ff2a:1aff:ffff:ffff:ffff:ffff:ffff:ffff
28ff2a:1b00::/24ff2a:1bff:ffff:ffff:ffff:ffff:ffff:ffff
29ff2a:1c00::/24ff2a:1cff:ffff:ffff:ffff:ffff:ffff:ffff
30ff2a:1d00::/24ff2a:1dff:ffff:ffff:ffff:ffff:ffff:ffff
31ff2a:1e00::/24ff2a:1eff:ffff:ffff:ffff:ffff:ffff:ffff
32ff2a:1f00::/24ff2a:1fff:ffff:ffff:ffff:ffff:ffff:ffff
33ff2a:2000::/24ff2a:20ff:ffff:ffff:ffff:ffff:ffff:ffff
34ff2a:2100::/24ff2a:21ff:ffff:ffff:ffff:ffff:ffff:ffff
35ff2a:2200::/24ff2a:22ff:ffff:ffff:ffff:ffff:ffff:ffff
36ff2a:2300::/24ff2a:23ff:ffff:ffff:ffff:ffff:ffff:ffff
37ff2a:2400::/24ff2a:24ff:ffff:ffff:ffff:ffff:ffff:ffff
38ff2a:2500::/24ff2a:25ff:ffff:ffff:ffff:ffff:ffff:ffff
39ff2a:2600::/24ff2a:26ff:ffff:ffff:ffff:ffff:ffff:ffff
40ff2a:2700::/24ff2a:27ff:ffff:ffff:ffff:ffff:ffff:ffff
41ff2a:2800::/24ff2a:28ff:ffff:ffff:ffff:ffff:ffff:ffff
42ff2a:2900::/24ff2a:29ff:ffff:ffff:ffff:ffff:ffff:ffff
43ff2a:2a00::/24ff2a:2aff:ffff:ffff:ffff:ffff:ffff:ffff
44ff2a:2b00::/24ff2a:2bff:ffff:ffff:ffff:ffff:ffff:ffff
45ff2a:2c00::/24ff2a:2cff:ffff:ffff:ffff:ffff:ffff:ffff
46ff2a:2d00::/24ff2a:2dff:ffff:ffff:ffff:ffff:ffff:ffff
47ff2a:2e00::/24ff2a:2eff:ffff:ffff:ffff:ffff:ffff:ffff
48ff2a:2f00::/24ff2a:2fff:ffff:ffff:ffff:ffff:ffff:ffff
49ff2a:3000::/24ff2a:30ff:ffff:ffff:ffff:ffff:ffff:ffff
50ff2a:3100::/24ff2a:31ff:ffff:ffff:ffff:ffff:ffff:ffff
51ff2a:3200::/24ff2a:32ff:ffff:ffff:ffff:ffff:ffff:ffff
52ff2a:3300::/24ff2a:33ff:ffff:ffff:ffff:ffff:ffff:ffff
53ff2a:3400::/24ff2a:34ff:ffff:ffff:ffff:ffff:ffff:ffff
54ff2a:3500::/24ff2a:35ff:ffff:ffff:ffff:ffff:ffff:ffff
55ff2a:3600::/24ff2a:36ff:ffff:ffff:ffff:ffff:ffff:ffff
56ff2a:3700::/24ff2a:37ff:ffff:ffff:ffff:ffff:ffff:ffff
57ff2a:3800::/24ff2a:38ff:ffff:ffff:ffff:ffff:ffff:ffff
58ff2a:3900::/24ff2a:39ff:ffff:ffff:ffff:ffff:ffff:ffff
59ff2a:3a00::/24ff2a:3aff:ffff:ffff:ffff:ffff:ffff:ffff
60ff2a:3b00::/24ff2a:3bff:ffff:ffff:ffff:ffff:ffff:ffff
61ff2a:3c00::/24ff2a:3cff:ffff:ffff:ffff:ffff:ffff:ffff
62ff2a:3d00::/24ff2a:3dff:ffff:ffff:ffff:ffff:ffff:ffff
63ff2a:3e00::/24ff2a:3eff:ffff:ffff:ffff:ffff:ffff:ffff
64ff2a:3f00::/24ff2a:3fff:ffff:ffff:ffff:ffff:ffff:ffff
65ff2a:4000::/24ff2a:40ff:ffff:ffff:ffff:ffff:ffff:ffff
66ff2a:4100::/24ff2a:41ff:ffff:ffff:ffff:ffff:ffff:ffff
67ff2a:4200::/24ff2a:42ff:ffff:ffff:ffff:ffff:ffff:ffff
68ff2a:4300::/24ff2a:43ff:ffff:ffff:ffff:ffff:ffff:ffff
69ff2a:4400::/24ff2a:44ff:ffff:ffff:ffff:ffff:ffff:ffff
70ff2a:4500::/24ff2a:45ff:ffff:ffff:ffff:ffff:ffff:ffff
71ff2a:4600::/24ff2a:46ff:ffff:ffff:ffff:ffff:ffff:ffff
72ff2a:4700::/24ff2a:47ff:ffff:ffff:ffff:ffff:ffff:ffff
73ff2a:4800::/24ff2a:48ff:ffff:ffff:ffff:ffff:ffff:ffff
74ff2a:4900::/24ff2a:49ff:ffff:ffff:ffff:ffff:ffff:ffff
75ff2a:4a00::/24ff2a:4aff:ffff:ffff:ffff:ffff:ffff:ffff
76ff2a:4b00::/24ff2a:4bff:ffff:ffff:ffff:ffff:ffff:ffff
77ff2a:4c00::/24ff2a:4cff:ffff:ffff:ffff:ffff:ffff:ffff
78ff2a:4d00::/24ff2a:4dff:ffff:ffff:ffff:ffff:ffff:ffff
79ff2a:4e00::/24ff2a:4eff:ffff:ffff:ffff:ffff:ffff:ffff
80ff2a:4f00::/24ff2a:4fff:ffff:ffff:ffff:ffff:ffff:ffff
81ff2a:5000::/24ff2a:50ff:ffff:ffff:ffff:ffff:ffff:ffff
82ff2a:5100::/24ff2a:51ff:ffff:ffff:ffff:ffff:ffff:ffff
83ff2a:5200::/24ff2a:52ff:ffff:ffff:ffff:ffff:ffff:ffff
84ff2a:5300::/24ff2a:53ff:ffff:ffff:ffff:ffff:ffff:ffff
85ff2a:5400::/24ff2a:54ff:ffff:ffff:ffff:ffff:ffff:ffff
86ff2a:5500::/24ff2a:55ff:ffff:ffff:ffff:ffff:ffff:ffff
87ff2a:5600::/24ff2a:56ff:ffff:ffff:ffff:ffff:ffff:ffff
88ff2a:5700::/24ff2a:57ff:ffff:ffff:ffff:ffff:ffff:ffff
89ff2a:5800::/24ff2a:58ff:ffff:ffff:ffff:ffff:ffff:ffff
90ff2a:5900::/24ff2a:59ff:ffff:ffff:ffff:ffff:ffff:ffff
91ff2a:5a00::/24ff2a:5aff:ffff:ffff:ffff:ffff:ffff:ffff
92ff2a:5b00::/24ff2a:5bff:ffff:ffff:ffff:ffff:ffff:ffff
93ff2a:5c00::/24ff2a:5cff:ffff:ffff:ffff:ffff:ffff:ffff
94ff2a:5d00::/24ff2a:5dff:ffff:ffff:ffff:ffff:ffff:ffff
95ff2a:5e00::/24ff2a:5eff:ffff:ffff:ffff:ffff:ffff:ffff
96ff2a:5f00::/24ff2a:5fff:ffff:ffff:ffff:ffff:ffff:ffff
97ff2a:6000::/24ff2a:60ff:ffff:ffff:ffff:ffff:ffff:ffff
98ff2a:6100::/24ff2a:61ff:ffff:ffff:ffff:ffff:ffff:ffff
99ff2a:6200::/24ff2a:62ff:ffff:ffff:ffff:ffff:ffff:ffff
100ff2a:6300::/24ff2a:63ff:ffff:ffff:ffff:ffff:ffff:ffff
101ff2a:6400::/24ff2a:64ff:ffff:ffff:ffff:ffff:ffff:ffff
102ff2a:6500::/24ff2a:65ff:ffff:ffff:ffff:ffff:ffff:ffff
103ff2a:6600::/24ff2a:66ff:ffff:ffff:ffff:ffff:ffff:ffff
104ff2a:6700::/24ff2a:67ff:ffff:ffff:ffff:ffff:ffff:ffff
105ff2a:6800::/24ff2a:68ff:ffff:ffff:ffff:ffff:ffff:ffff
106ff2a:6900::/24ff2a:69ff:ffff:ffff:ffff:ffff:ffff:ffff
107ff2a:6a00::/24ff2a:6aff:ffff:ffff:ffff:ffff:ffff:ffff
108ff2a:6b00::/24ff2a:6bff:ffff:ffff:ffff:ffff:ffff:ffff
109ff2a:6c00::/24ff2a:6cff:ffff:ffff:ffff:ffff:ffff:ffff
110ff2a:6d00::/24ff2a:6dff:ffff:ffff:ffff:ffff:ffff:ffff
111ff2a:6e00::/24ff2a:6eff:ffff:ffff:ffff:ffff:ffff:ffff
112ff2a:6f00::/24ff2a:6fff:ffff:ffff:ffff:ffff:ffff:ffff
113ff2a:7000::/24ff2a:70ff:ffff:ffff:ffff:ffff:ffff:ffff
114ff2a:7100::/24ff2a:71ff:ffff:ffff:ffff:ffff:ffff:ffff
115ff2a:7200::/24ff2a:72ff:ffff:ffff:ffff:ffff:ffff:ffff
116ff2a:7300::/24ff2a:73ff:ffff:ffff:ffff:ffff:ffff:ffff
117ff2a:7400::/24ff2a:74ff:ffff:ffff:ffff:ffff:ffff:ffff
118ff2a:7500::/24ff2a:75ff:ffff:ffff:ffff:ffff:ffff:ffff
119ff2a:7600::/24ff2a:76ff:ffff:ffff:ffff:ffff:ffff:ffff
120ff2a:7700::/24ff2a:77ff:ffff:ffff:ffff:ffff:ffff:ffff
121ff2a:7800::/24ff2a:78ff:ffff:ffff:ffff:ffff:ffff:ffff
122ff2a:7900::/24ff2a:79ff:ffff:ffff:ffff:ffff:ffff:ffff
123ff2a:7a00::/24ff2a:7aff:ffff:ffff:ffff:ffff:ffff:ffff
124ff2a:7b00::/24ff2a:7bff:ffff:ffff:ffff:ffff:ffff:ffff
125ff2a:7c00::/24ff2a:7cff:ffff:ffff:ffff:ffff:ffff:ffff
126ff2a:7d00::/24ff2a:7dff:ffff:ffff:ffff:ffff:ffff:ffff
127ff2a:7e00::/24ff2a:7eff:ffff:ffff:ffff:ffff:ffff:ffff
128ff2a:7f00::/24ff2a:7fff:ffff:ffff:ffff:ffff:ffff:ffff
129ff2a:8000::/24ff2a:80ff:ffff:ffff:ffff:ffff:ffff:ffff
130ff2a:8100::/24ff2a:81ff:ffff:ffff:ffff:ffff:ffff:ffff
131ff2a:8200::/24ff2a:82ff:ffff:ffff:ffff:ffff:ffff:ffff
132ff2a:8300::/24ff2a:83ff:ffff:ffff:ffff:ffff:ffff:ffff
133ff2a:8400::/24ff2a:84ff:ffff:ffff:ffff:ffff:ffff:ffff
134ff2a:8500::/24ff2a:85ff:ffff:ffff:ffff:ffff:ffff:ffff
135ff2a:8600::/24ff2a:86ff:ffff:ffff:ffff:ffff:ffff:ffff
136ff2a:8700::/24ff2a:87ff:ffff:ffff:ffff:ffff:ffff:ffff
137ff2a:8800::/24ff2a:88ff:ffff:ffff:ffff:ffff:ffff:ffff
138ff2a:8900::/24ff2a:89ff:ffff:ffff:ffff:ffff:ffff:ffff
139ff2a:8a00::/24ff2a:8aff:ffff:ffff:ffff:ffff:ffff:ffff
140ff2a:8b00::/24ff2a:8bff:ffff:ffff:ffff:ffff:ffff:ffff
141ff2a:8c00::/24ff2a:8cff:ffff:ffff:ffff:ffff:ffff:ffff
142ff2a:8d00::/24ff2a:8dff:ffff:ffff:ffff:ffff:ffff:ffff
143ff2a:8e00::/24ff2a:8eff:ffff:ffff:ffff:ffff:ffff:ffff
144ff2a:8f00::/24ff2a:8fff:ffff:ffff:ffff:ffff:ffff:ffff
145ff2a:9000::/24ff2a:90ff:ffff:ffff:ffff:ffff:ffff:ffff
146ff2a:9100::/24ff2a:91ff:ffff:ffff:ffff:ffff:ffff:ffff
147ff2a:9200::/24ff2a:92ff:ffff:ffff:ffff:ffff:ffff:ffff
148ff2a:9300::/24ff2a:93ff:ffff:ffff:ffff:ffff:ffff:ffff
149ff2a:9400::/24ff2a:94ff:ffff:ffff:ffff:ffff:ffff:ffff
150ff2a:9500::/24ff2a:95ff:ffff:ffff:ffff:ffff:ffff:ffff
151ff2a:9600::/24ff2a:96ff:ffff:ffff:ffff:ffff:ffff:ffff
152ff2a:9700::/24ff2a:97ff:ffff:ffff:ffff:ffff:ffff:ffff
153ff2a:9800::/24ff2a:98ff:ffff:ffff:ffff:ffff:ffff:ffff
154ff2a:9900::/24ff2a:99ff:ffff:ffff:ffff:ffff:ffff:ffff
155ff2a:9a00::/24ff2a:9aff:ffff:ffff:ffff:ffff:ffff:ffff
156ff2a:9b00::/24ff2a:9bff:ffff:ffff:ffff:ffff:ffff:ffff
157ff2a:9c00::/24ff2a:9cff:ffff:ffff:ffff:ffff:ffff:ffff
158ff2a:9d00::/24ff2a:9dff:ffff:ffff:ffff:ffff:ffff:ffff
159ff2a:9e00::/24ff2a:9eff:ffff:ffff:ffff:ffff:ffff:ffff
160ff2a:9f00::/24ff2a:9fff:ffff:ffff:ffff:ffff:ffff:ffff
161ff2a:a000::/24ff2a:a0ff:ffff:ffff:ffff:ffff:ffff:ffff
162ff2a:a100::/24ff2a:a1ff:ffff:ffff:ffff:ffff:ffff:ffff
163ff2a:a200::/24ff2a:a2ff:ffff:ffff:ffff:ffff:ffff:ffff
164ff2a:a300::/24ff2a:a3ff:ffff:ffff:ffff:ffff:ffff:ffff
165ff2a:a400::/24ff2a:a4ff:ffff:ffff:ffff:ffff:ffff:ffff
166ff2a:a500::/24ff2a:a5ff:ffff:ffff:ffff:ffff:ffff:ffff
167ff2a:a600::/24ff2a:a6ff:ffff:ffff:ffff:ffff:ffff:ffff
168ff2a:a700::/24ff2a:a7ff:ffff:ffff:ffff:ffff:ffff:ffff
169ff2a:a800::/24ff2a:a8ff:ffff:ffff:ffff:ffff:ffff:ffff
170ff2a:a900::/24ff2a:a9ff:ffff:ffff:ffff:ffff:ffff:ffff
171ff2a:aa00::/24ff2a:aaff:ffff:ffff:ffff:ffff:ffff:ffff
172ff2a:ab00::/24ff2a:abff:ffff:ffff:ffff:ffff:ffff:ffff
173ff2a:ac00::/24ff2a:acff:ffff:ffff:ffff:ffff:ffff:ffff
174ff2a:ad00::/24ff2a:adff:ffff:ffff:ffff:ffff:ffff:ffff
175ff2a:ae00::/24ff2a:aeff:ffff:ffff:ffff:ffff:ffff:ffff
176ff2a:af00::/24ff2a:afff:ffff:ffff:ffff:ffff:ffff:ffff
177ff2a:b000::/24ff2a:b0ff:ffff:ffff:ffff:ffff:ffff:ffff
178ff2a:b100::/24ff2a:b1ff:ffff:ffff:ffff:ffff:ffff:ffff
179ff2a:b200::/24ff2a:b2ff:ffff:ffff:ffff:ffff:ffff:ffff
180ff2a:b300::/24ff2a:b3ff:ffff:ffff:ffff:ffff:ffff:ffff
181ff2a:b400::/24ff2a:b4ff:ffff:ffff:ffff:ffff:ffff:ffff
182ff2a:b500::/24ff2a:b5ff:ffff:ffff:ffff:ffff:ffff:ffff
183ff2a:b600::/24ff2a:b6ff:ffff:ffff:ffff:ffff:ffff:ffff
184ff2a:b700::/24ff2a:b7ff:ffff:ffff:ffff:ffff:ffff:ffff
185ff2a:b800::/24ff2a:b8ff:ffff:ffff:ffff:ffff:ffff:ffff
186ff2a:b900::/24ff2a:b9ff:ffff:ffff:ffff:ffff:ffff:ffff
187ff2a:ba00::/24ff2a:baff:ffff:ffff:ffff:ffff:ffff:ffff
188ff2a:bb00::/24ff2a:bbff:ffff:ffff:ffff:ffff:ffff:ffff
189ff2a:bc00::/24ff2a:bcff:ffff:ffff:ffff:ffff:ffff:ffff
190ff2a:bd00::/24ff2a:bdff:ffff:ffff:ffff:ffff:ffff:ffff
191ff2a:be00::/24ff2a:beff:ffff:ffff:ffff:ffff:ffff:ffff
192ff2a:bf00::/24ff2a:bfff:ffff:ffff:ffff:ffff:ffff:ffff
193ff2a:c000::/24ff2a:c0ff:ffff:ffff:ffff:ffff:ffff:ffff
194ff2a:c100::/24ff2a:c1ff:ffff:ffff:ffff:ffff:ffff:ffff
195ff2a:c200::/24ff2a:c2ff:ffff:ffff:ffff:ffff:ffff:ffff
196ff2a:c300::/24ff2a:c3ff:ffff:ffff:ffff:ffff:ffff:ffff
197ff2a:c400::/24ff2a:c4ff:ffff:ffff:ffff:ffff:ffff:ffff
198ff2a:c500::/24ff2a:c5ff:ffff:ffff:ffff:ffff:ffff:ffff
199ff2a:c600::/24ff2a:c6ff:ffff:ffff:ffff:ffff:ffff:ffff
200ff2a:c700::/24ff2a:c7ff:ffff:ffff:ffff:ffff:ffff:ffff
201ff2a:c800::/24ff2a:c8ff:ffff:ffff:ffff:ffff:ffff:ffff
202ff2a:c900::/24ff2a:c9ff:ffff:ffff:ffff:ffff:ffff:ffff
203ff2a:ca00::/24ff2a:caff:ffff:ffff:ffff:ffff:ffff:ffff
204ff2a:cb00::/24ff2a:cbff:ffff:ffff:ffff:ffff:ffff:ffff
205ff2a:cc00::/24ff2a:ccff:ffff:ffff:ffff:ffff:ffff:ffff
206ff2a:cd00::/24ff2a:cdff:ffff:ffff:ffff:ffff:ffff:ffff
207ff2a:ce00::/24ff2a:ceff:ffff:ffff:ffff:ffff:ffff:ffff
208ff2a:cf00::/24ff2a:cfff:ffff:ffff:ffff:ffff:ffff:ffff
209ff2a:d000::/24ff2a:d0ff:ffff:ffff:ffff:ffff:ffff:ffff
210ff2a:d100::/24ff2a:d1ff:ffff:ffff:ffff:ffff:ffff:ffff
211ff2a:d200::/24ff2a:d2ff:ffff:ffff:ffff:ffff:ffff:ffff
212ff2a:d300::/24ff2a:d3ff:ffff:ffff:ffff:ffff:ffff:ffff
213ff2a:d400::/24ff2a:d4ff:ffff:ffff:ffff:ffff:ffff:ffff
214ff2a:d500::/24ff2a:d5ff:ffff:ffff:ffff:ffff:ffff:ffff
215ff2a:d600::/24ff2a:d6ff:ffff:ffff:ffff:ffff:ffff:ffff
216ff2a:d700::/24ff2a:d7ff:ffff:ffff:ffff:ffff:ffff:ffff
217ff2a:d800::/24ff2a:d8ff:ffff:ffff:ffff:ffff:ffff:ffff
218ff2a:d900::/24ff2a:d9ff:ffff:ffff:ffff:ffff:ffff:ffff
219ff2a:da00::/24ff2a:daff:ffff:ffff:ffff:ffff:ffff:ffff
220ff2a:db00::/24ff2a:dbff:ffff:ffff:ffff:ffff:ffff:ffff
221ff2a:dc00::/24ff2a:dcff:ffff:ffff:ffff:ffff:ffff:ffff
222ff2a:dd00::/24ff2a:ddff:ffff:ffff:ffff:ffff:ffff:ffff
223ff2a:de00::/24ff2a:deff:ffff:ffff:ffff:ffff:ffff:ffff
224ff2a:df00::/24ff2a:dfff:ffff:ffff:ffff:ffff:ffff:ffff
225ff2a:e000::/24ff2a:e0ff:ffff:ffff:ffff:ffff:ffff:ffff
226ff2a:e100::/24ff2a:e1ff:ffff:ffff:ffff:ffff:ffff:ffff
227ff2a:e200::/24ff2a:e2ff:ffff:ffff:ffff:ffff:ffff:ffff
228ff2a:e300::/24ff2a:e3ff:ffff:ffff:ffff:ffff:ffff:ffff
229ff2a:e400::/24ff2a:e4ff:ffff:ffff:ffff:ffff:ffff:ffff
230ff2a:e500::/24ff2a:e5ff:ffff:ffff:ffff:ffff:ffff:ffff
231ff2a:e600::/24ff2a:e6ff:ffff:ffff:ffff:ffff:ffff:ffff
232ff2a:e700::/24ff2a:e7ff:ffff:ffff:ffff:ffff:ffff:ffff
233ff2a:e800::/24ff2a:e8ff:ffff:ffff:ffff:ffff:ffff:ffff
234ff2a:e900::/24ff2a:e9ff:ffff:ffff:ffff:ffff:ffff:ffff
235ff2a:ea00::/24ff2a:eaff:ffff:ffff:ffff:ffff:ffff:ffff
236ff2a:eb00::/24ff2a:ebff:ffff:ffff:ffff:ffff:ffff:ffff
237ff2a:ec00::/24ff2a:ecff:ffff:ffff:ffff:ffff:ffff:ffff
238ff2a:ed00::/24ff2a:edff:ffff:ffff:ffff:ffff:ffff:ffff
239ff2a:ee00::/24ff2a:eeff:ffff:ffff:ffff:ffff:ffff:ffff
240ff2a:ef00::/24ff2a:efff:ffff:ffff:ffff:ffff:ffff:ffff
241ff2a:f000::/24ff2a:f0ff:ffff:ffff:ffff:ffff:ffff:ffff
242ff2a:f100::/24ff2a:f1ff:ffff:ffff:ffff:ffff:ffff:ffff
243ff2a:f200::/24ff2a:f2ff:ffff:ffff:ffff:ffff:ffff:ffff
244ff2a:f300::/24ff2a:f3ff:ffff:ffff:ffff:ffff:ffff:ffff
245ff2a:f400::/24ff2a:f4ff:ffff:ffff:ffff:ffff:ffff:ffff
246ff2a:f500::/24ff2a:f5ff:ffff:ffff:ffff:ffff:ffff:ffff
247ff2a:f600::/24ff2a:f6ff:ffff:ffff:ffff:ffff:ffff:ffff
248ff2a:f700::/24ff2a:f7ff:ffff:ffff:ffff:ffff:ffff:ffff
249ff2a:f800::/24ff2a:f8ff:ffff:ffff:ffff:ffff:ffff:ffff
250ff2a:f900::/24ff2a:f9ff:ffff:ffff:ffff:ffff:ffff:ffff
251ff2a:fa00::/24ff2a:faff:ffff:ffff:ffff:ffff:ffff:ffff
252ff2a:fb00::/24ff2a:fbff:ffff:ffff:ffff:ffff:ffff:ffff
253ff2a:fc00::/24ff2a:fcff:ffff:ffff:ffff:ffff:ffff:ffff
254ff2a:fd00::/24ff2a:fdff:ffff:ffff:ffff:ffff:ffff:ffff
255ff2a:fe00::/24ff2a:feff:ffff:ffff:ffff:ffff:ffff:ffff
256ff2a:ff00::/24ff2a: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.