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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
ff5d::/16
First address
ff5d::
Last address
ff5d: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
ff5d:0000:0000:0000:0000:0000:0000:0000
Type
Multicast ff00::/8
One-to-many traffic; replaces broadcast
Reverse DNS zone
d.5.f.f.ip6.arpa
Split into smaller subnets/32
/17 (2)/18 (4)/19 (8)/20 (16)/24 (256)/28 (4,096)/32 (65,536)

ff5d::/16 makes 65,536 subnets of /32; the first 256 are listed.

Subnets
#SubnetLast address
1ff5d::/32ff5d:0:ffff:ffff:ffff:ffff:ffff:ffff
2ff5d:1::/32ff5d:1:ffff:ffff:ffff:ffff:ffff:ffff
3ff5d:2::/32ff5d:2:ffff:ffff:ffff:ffff:ffff:ffff
4ff5d:3::/32ff5d:3:ffff:ffff:ffff:ffff:ffff:ffff
5ff5d:4::/32ff5d:4:ffff:ffff:ffff:ffff:ffff:ffff
6ff5d:5::/32ff5d:5:ffff:ffff:ffff:ffff:ffff:ffff
7ff5d:6::/32ff5d:6:ffff:ffff:ffff:ffff:ffff:ffff
8ff5d:7::/32ff5d:7:ffff:ffff:ffff:ffff:ffff:ffff
9ff5d:8::/32ff5d:8:ffff:ffff:ffff:ffff:ffff:ffff
10ff5d:9::/32ff5d:9:ffff:ffff:ffff:ffff:ffff:ffff
11ff5d:a::/32ff5d:a:ffff:ffff:ffff:ffff:ffff:ffff
12ff5d:b::/32ff5d:b:ffff:ffff:ffff:ffff:ffff:ffff
13ff5d:c::/32ff5d:c:ffff:ffff:ffff:ffff:ffff:ffff
14ff5d:d::/32ff5d:d:ffff:ffff:ffff:ffff:ffff:ffff
15ff5d:e::/32ff5d:e:ffff:ffff:ffff:ffff:ffff:ffff
16ff5d:f::/32ff5d:f:ffff:ffff:ffff:ffff:ffff:ffff
17ff5d:10::/32ff5d:10:ffff:ffff:ffff:ffff:ffff:ffff
18ff5d:11::/32ff5d:11:ffff:ffff:ffff:ffff:ffff:ffff
19ff5d:12::/32ff5d:12:ffff:ffff:ffff:ffff:ffff:ffff
20ff5d:13::/32ff5d:13:ffff:ffff:ffff:ffff:ffff:ffff
21ff5d:14::/32ff5d:14:ffff:ffff:ffff:ffff:ffff:ffff
22ff5d:15::/32ff5d:15:ffff:ffff:ffff:ffff:ffff:ffff
23ff5d:16::/32ff5d:16:ffff:ffff:ffff:ffff:ffff:ffff
24ff5d:17::/32ff5d:17:ffff:ffff:ffff:ffff:ffff:ffff
25ff5d:18::/32ff5d:18:ffff:ffff:ffff:ffff:ffff:ffff
26ff5d:19::/32ff5d:19:ffff:ffff:ffff:ffff:ffff:ffff
27ff5d:1a::/32ff5d:1a:ffff:ffff:ffff:ffff:ffff:ffff
28ff5d:1b::/32ff5d:1b:ffff:ffff:ffff:ffff:ffff:ffff
29ff5d:1c::/32ff5d:1c:ffff:ffff:ffff:ffff:ffff:ffff
30ff5d:1d::/32ff5d:1d:ffff:ffff:ffff:ffff:ffff:ffff
31ff5d:1e::/32ff5d:1e:ffff:ffff:ffff:ffff:ffff:ffff
32ff5d:1f::/32ff5d:1f:ffff:ffff:ffff:ffff:ffff:ffff
33ff5d:20::/32ff5d:20:ffff:ffff:ffff:ffff:ffff:ffff
34ff5d:21::/32ff5d:21:ffff:ffff:ffff:ffff:ffff:ffff
35ff5d:22::/32ff5d:22:ffff:ffff:ffff:ffff:ffff:ffff
36ff5d:23::/32ff5d:23:ffff:ffff:ffff:ffff:ffff:ffff
37ff5d:24::/32ff5d:24:ffff:ffff:ffff:ffff:ffff:ffff
38ff5d:25::/32ff5d:25:ffff:ffff:ffff:ffff:ffff:ffff
39ff5d:26::/32ff5d:26:ffff:ffff:ffff:ffff:ffff:ffff
40ff5d:27::/32ff5d:27:ffff:ffff:ffff:ffff:ffff:ffff
41ff5d:28::/32ff5d:28:ffff:ffff:ffff:ffff:ffff:ffff
42ff5d:29::/32ff5d:29:ffff:ffff:ffff:ffff:ffff:ffff
43ff5d:2a::/32ff5d:2a:ffff:ffff:ffff:ffff:ffff:ffff
44ff5d:2b::/32ff5d:2b:ffff:ffff:ffff:ffff:ffff:ffff
45ff5d:2c::/32ff5d:2c:ffff:ffff:ffff:ffff:ffff:ffff
46ff5d:2d::/32ff5d:2d:ffff:ffff:ffff:ffff:ffff:ffff
47ff5d:2e::/32ff5d:2e:ffff:ffff:ffff:ffff:ffff:ffff
48ff5d:2f::/32ff5d:2f:ffff:ffff:ffff:ffff:ffff:ffff
49ff5d:30::/32ff5d:30:ffff:ffff:ffff:ffff:ffff:ffff
50ff5d:31::/32ff5d:31:ffff:ffff:ffff:ffff:ffff:ffff
51ff5d:32::/32ff5d:32:ffff:ffff:ffff:ffff:ffff:ffff
52ff5d:33::/32ff5d:33:ffff:ffff:ffff:ffff:ffff:ffff
53ff5d:34::/32ff5d:34:ffff:ffff:ffff:ffff:ffff:ffff
54ff5d:35::/32ff5d:35:ffff:ffff:ffff:ffff:ffff:ffff
55ff5d:36::/32ff5d:36:ffff:ffff:ffff:ffff:ffff:ffff
56ff5d:37::/32ff5d:37:ffff:ffff:ffff:ffff:ffff:ffff
57ff5d:38::/32ff5d:38:ffff:ffff:ffff:ffff:ffff:ffff
58ff5d:39::/32ff5d:39:ffff:ffff:ffff:ffff:ffff:ffff
59ff5d:3a::/32ff5d:3a:ffff:ffff:ffff:ffff:ffff:ffff
60ff5d:3b::/32ff5d:3b:ffff:ffff:ffff:ffff:ffff:ffff
61ff5d:3c::/32ff5d:3c:ffff:ffff:ffff:ffff:ffff:ffff
62ff5d:3d::/32ff5d:3d:ffff:ffff:ffff:ffff:ffff:ffff
63ff5d:3e::/32ff5d:3e:ffff:ffff:ffff:ffff:ffff:ffff
64ff5d:3f::/32ff5d:3f:ffff:ffff:ffff:ffff:ffff:ffff
65ff5d:40::/32ff5d:40:ffff:ffff:ffff:ffff:ffff:ffff
66ff5d:41::/32ff5d:41:ffff:ffff:ffff:ffff:ffff:ffff
67ff5d:42::/32ff5d:42:ffff:ffff:ffff:ffff:ffff:ffff
68ff5d:43::/32ff5d:43:ffff:ffff:ffff:ffff:ffff:ffff
69ff5d:44::/32ff5d:44:ffff:ffff:ffff:ffff:ffff:ffff
70ff5d:45::/32ff5d:45:ffff:ffff:ffff:ffff:ffff:ffff
71ff5d:46::/32ff5d:46:ffff:ffff:ffff:ffff:ffff:ffff
72ff5d:47::/32ff5d:47:ffff:ffff:ffff:ffff:ffff:ffff
73ff5d:48::/32ff5d:48:ffff:ffff:ffff:ffff:ffff:ffff
74ff5d:49::/32ff5d:49:ffff:ffff:ffff:ffff:ffff:ffff
75ff5d:4a::/32ff5d:4a:ffff:ffff:ffff:ffff:ffff:ffff
76ff5d:4b::/32ff5d:4b:ffff:ffff:ffff:ffff:ffff:ffff
77ff5d:4c::/32ff5d:4c:ffff:ffff:ffff:ffff:ffff:ffff
78ff5d:4d::/32ff5d:4d:ffff:ffff:ffff:ffff:ffff:ffff
79ff5d:4e::/32ff5d:4e:ffff:ffff:ffff:ffff:ffff:ffff
80ff5d:4f::/32ff5d:4f:ffff:ffff:ffff:ffff:ffff:ffff
81ff5d:50::/32ff5d:50:ffff:ffff:ffff:ffff:ffff:ffff
82ff5d:51::/32ff5d:51:ffff:ffff:ffff:ffff:ffff:ffff
83ff5d:52::/32ff5d:52:ffff:ffff:ffff:ffff:ffff:ffff
84ff5d:53::/32ff5d:53:ffff:ffff:ffff:ffff:ffff:ffff
85ff5d:54::/32ff5d:54:ffff:ffff:ffff:ffff:ffff:ffff
86ff5d:55::/32ff5d:55:ffff:ffff:ffff:ffff:ffff:ffff
87ff5d:56::/32ff5d:56:ffff:ffff:ffff:ffff:ffff:ffff
88ff5d:57::/32ff5d:57:ffff:ffff:ffff:ffff:ffff:ffff
89ff5d:58::/32ff5d:58:ffff:ffff:ffff:ffff:ffff:ffff
90ff5d:59::/32ff5d:59:ffff:ffff:ffff:ffff:ffff:ffff
91ff5d:5a::/32ff5d:5a:ffff:ffff:ffff:ffff:ffff:ffff
92ff5d:5b::/32ff5d:5b:ffff:ffff:ffff:ffff:ffff:ffff
93ff5d:5c::/32ff5d:5c:ffff:ffff:ffff:ffff:ffff:ffff
94ff5d:5d::/32ff5d:5d:ffff:ffff:ffff:ffff:ffff:ffff
95ff5d:5e::/32ff5d:5e:ffff:ffff:ffff:ffff:ffff:ffff
96ff5d:5f::/32ff5d:5f:ffff:ffff:ffff:ffff:ffff:ffff
97ff5d:60::/32ff5d:60:ffff:ffff:ffff:ffff:ffff:ffff
98ff5d:61::/32ff5d:61:ffff:ffff:ffff:ffff:ffff:ffff
99ff5d:62::/32ff5d:62:ffff:ffff:ffff:ffff:ffff:ffff
100ff5d:63::/32ff5d:63:ffff:ffff:ffff:ffff:ffff:ffff
101ff5d:64::/32ff5d:64:ffff:ffff:ffff:ffff:ffff:ffff
102ff5d:65::/32ff5d:65:ffff:ffff:ffff:ffff:ffff:ffff
103ff5d:66::/32ff5d:66:ffff:ffff:ffff:ffff:ffff:ffff
104ff5d:67::/32ff5d:67:ffff:ffff:ffff:ffff:ffff:ffff
105ff5d:68::/32ff5d:68:ffff:ffff:ffff:ffff:ffff:ffff
106ff5d:69::/32ff5d:69:ffff:ffff:ffff:ffff:ffff:ffff
107ff5d:6a::/32ff5d:6a:ffff:ffff:ffff:ffff:ffff:ffff
108ff5d:6b::/32ff5d:6b:ffff:ffff:ffff:ffff:ffff:ffff
109ff5d:6c::/32ff5d:6c:ffff:ffff:ffff:ffff:ffff:ffff
110ff5d:6d::/32ff5d:6d:ffff:ffff:ffff:ffff:ffff:ffff
111ff5d:6e::/32ff5d:6e:ffff:ffff:ffff:ffff:ffff:ffff
112ff5d:6f::/32ff5d:6f:ffff:ffff:ffff:ffff:ffff:ffff
113ff5d:70::/32ff5d:70:ffff:ffff:ffff:ffff:ffff:ffff
114ff5d:71::/32ff5d:71:ffff:ffff:ffff:ffff:ffff:ffff
115ff5d:72::/32ff5d:72:ffff:ffff:ffff:ffff:ffff:ffff
116ff5d:73::/32ff5d:73:ffff:ffff:ffff:ffff:ffff:ffff
117ff5d:74::/32ff5d:74:ffff:ffff:ffff:ffff:ffff:ffff
118ff5d:75::/32ff5d:75:ffff:ffff:ffff:ffff:ffff:ffff
119ff5d:76::/32ff5d:76:ffff:ffff:ffff:ffff:ffff:ffff
120ff5d:77::/32ff5d:77:ffff:ffff:ffff:ffff:ffff:ffff
121ff5d:78::/32ff5d:78:ffff:ffff:ffff:ffff:ffff:ffff
122ff5d:79::/32ff5d:79:ffff:ffff:ffff:ffff:ffff:ffff
123ff5d:7a::/32ff5d:7a:ffff:ffff:ffff:ffff:ffff:ffff
124ff5d:7b::/32ff5d:7b:ffff:ffff:ffff:ffff:ffff:ffff
125ff5d:7c::/32ff5d:7c:ffff:ffff:ffff:ffff:ffff:ffff
126ff5d:7d::/32ff5d:7d:ffff:ffff:ffff:ffff:ffff:ffff
127ff5d:7e::/32ff5d:7e:ffff:ffff:ffff:ffff:ffff:ffff
128ff5d:7f::/32ff5d:7f:ffff:ffff:ffff:ffff:ffff:ffff
129ff5d:80::/32ff5d:80:ffff:ffff:ffff:ffff:ffff:ffff
130ff5d:81::/32ff5d:81:ffff:ffff:ffff:ffff:ffff:ffff
131ff5d:82::/32ff5d:82:ffff:ffff:ffff:ffff:ffff:ffff
132ff5d:83::/32ff5d:83:ffff:ffff:ffff:ffff:ffff:ffff
133ff5d:84::/32ff5d:84:ffff:ffff:ffff:ffff:ffff:ffff
134ff5d:85::/32ff5d:85:ffff:ffff:ffff:ffff:ffff:ffff
135ff5d:86::/32ff5d:86:ffff:ffff:ffff:ffff:ffff:ffff
136ff5d:87::/32ff5d:87:ffff:ffff:ffff:ffff:ffff:ffff
137ff5d:88::/32ff5d:88:ffff:ffff:ffff:ffff:ffff:ffff
138ff5d:89::/32ff5d:89:ffff:ffff:ffff:ffff:ffff:ffff
139ff5d:8a::/32ff5d:8a:ffff:ffff:ffff:ffff:ffff:ffff
140ff5d:8b::/32ff5d:8b:ffff:ffff:ffff:ffff:ffff:ffff
141ff5d:8c::/32ff5d:8c:ffff:ffff:ffff:ffff:ffff:ffff
142ff5d:8d::/32ff5d:8d:ffff:ffff:ffff:ffff:ffff:ffff
143ff5d:8e::/32ff5d:8e:ffff:ffff:ffff:ffff:ffff:ffff
144ff5d:8f::/32ff5d:8f:ffff:ffff:ffff:ffff:ffff:ffff
145ff5d:90::/32ff5d:90:ffff:ffff:ffff:ffff:ffff:ffff
146ff5d:91::/32ff5d:91:ffff:ffff:ffff:ffff:ffff:ffff
147ff5d:92::/32ff5d:92:ffff:ffff:ffff:ffff:ffff:ffff
148ff5d:93::/32ff5d:93:ffff:ffff:ffff:ffff:ffff:ffff
149ff5d:94::/32ff5d:94:ffff:ffff:ffff:ffff:ffff:ffff
150ff5d:95::/32ff5d:95:ffff:ffff:ffff:ffff:ffff:ffff
151ff5d:96::/32ff5d:96:ffff:ffff:ffff:ffff:ffff:ffff
152ff5d:97::/32ff5d:97:ffff:ffff:ffff:ffff:ffff:ffff
153ff5d:98::/32ff5d:98:ffff:ffff:ffff:ffff:ffff:ffff
154ff5d:99::/32ff5d:99:ffff:ffff:ffff:ffff:ffff:ffff
155ff5d:9a::/32ff5d:9a:ffff:ffff:ffff:ffff:ffff:ffff
156ff5d:9b::/32ff5d:9b:ffff:ffff:ffff:ffff:ffff:ffff
157ff5d:9c::/32ff5d:9c:ffff:ffff:ffff:ffff:ffff:ffff
158ff5d:9d::/32ff5d:9d:ffff:ffff:ffff:ffff:ffff:ffff
159ff5d:9e::/32ff5d:9e:ffff:ffff:ffff:ffff:ffff:ffff
160ff5d:9f::/32ff5d:9f:ffff:ffff:ffff:ffff:ffff:ffff
161ff5d:a0::/32ff5d:a0:ffff:ffff:ffff:ffff:ffff:ffff
162ff5d:a1::/32ff5d:a1:ffff:ffff:ffff:ffff:ffff:ffff
163ff5d:a2::/32ff5d:a2:ffff:ffff:ffff:ffff:ffff:ffff
164ff5d:a3::/32ff5d:a3:ffff:ffff:ffff:ffff:ffff:ffff
165ff5d:a4::/32ff5d:a4:ffff:ffff:ffff:ffff:ffff:ffff
166ff5d:a5::/32ff5d:a5:ffff:ffff:ffff:ffff:ffff:ffff
167ff5d:a6::/32ff5d:a6:ffff:ffff:ffff:ffff:ffff:ffff
168ff5d:a7::/32ff5d:a7:ffff:ffff:ffff:ffff:ffff:ffff
169ff5d:a8::/32ff5d:a8:ffff:ffff:ffff:ffff:ffff:ffff
170ff5d:a9::/32ff5d:a9:ffff:ffff:ffff:ffff:ffff:ffff
171ff5d:aa::/32ff5d:aa:ffff:ffff:ffff:ffff:ffff:ffff
172ff5d:ab::/32ff5d:ab:ffff:ffff:ffff:ffff:ffff:ffff
173ff5d:ac::/32ff5d:ac:ffff:ffff:ffff:ffff:ffff:ffff
174ff5d:ad::/32ff5d:ad:ffff:ffff:ffff:ffff:ffff:ffff
175ff5d:ae::/32ff5d:ae:ffff:ffff:ffff:ffff:ffff:ffff
176ff5d:af::/32ff5d:af:ffff:ffff:ffff:ffff:ffff:ffff
177ff5d:b0::/32ff5d:b0:ffff:ffff:ffff:ffff:ffff:ffff
178ff5d:b1::/32ff5d:b1:ffff:ffff:ffff:ffff:ffff:ffff
179ff5d:b2::/32ff5d:b2:ffff:ffff:ffff:ffff:ffff:ffff
180ff5d:b3::/32ff5d:b3:ffff:ffff:ffff:ffff:ffff:ffff
181ff5d:b4::/32ff5d:b4:ffff:ffff:ffff:ffff:ffff:ffff
182ff5d:b5::/32ff5d:b5:ffff:ffff:ffff:ffff:ffff:ffff
183ff5d:b6::/32ff5d:b6:ffff:ffff:ffff:ffff:ffff:ffff
184ff5d:b7::/32ff5d:b7:ffff:ffff:ffff:ffff:ffff:ffff
185ff5d:b8::/32ff5d:b8:ffff:ffff:ffff:ffff:ffff:ffff
186ff5d:b9::/32ff5d:b9:ffff:ffff:ffff:ffff:ffff:ffff
187ff5d:ba::/32ff5d:ba:ffff:ffff:ffff:ffff:ffff:ffff
188ff5d:bb::/32ff5d:bb:ffff:ffff:ffff:ffff:ffff:ffff
189ff5d:bc::/32ff5d:bc:ffff:ffff:ffff:ffff:ffff:ffff
190ff5d:bd::/32ff5d:bd:ffff:ffff:ffff:ffff:ffff:ffff
191ff5d:be::/32ff5d:be:ffff:ffff:ffff:ffff:ffff:ffff
192ff5d:bf::/32ff5d:bf:ffff:ffff:ffff:ffff:ffff:ffff
193ff5d:c0::/32ff5d:c0:ffff:ffff:ffff:ffff:ffff:ffff
194ff5d:c1::/32ff5d:c1:ffff:ffff:ffff:ffff:ffff:ffff
195ff5d:c2::/32ff5d:c2:ffff:ffff:ffff:ffff:ffff:ffff
196ff5d:c3::/32ff5d:c3:ffff:ffff:ffff:ffff:ffff:ffff
197ff5d:c4::/32ff5d:c4:ffff:ffff:ffff:ffff:ffff:ffff
198ff5d:c5::/32ff5d:c5:ffff:ffff:ffff:ffff:ffff:ffff
199ff5d:c6::/32ff5d:c6:ffff:ffff:ffff:ffff:ffff:ffff
200ff5d:c7::/32ff5d:c7:ffff:ffff:ffff:ffff:ffff:ffff
201ff5d:c8::/32ff5d:c8:ffff:ffff:ffff:ffff:ffff:ffff
202ff5d:c9::/32ff5d:c9:ffff:ffff:ffff:ffff:ffff:ffff
203ff5d:ca::/32ff5d:ca:ffff:ffff:ffff:ffff:ffff:ffff
204ff5d:cb::/32ff5d:cb:ffff:ffff:ffff:ffff:ffff:ffff
205ff5d:cc::/32ff5d:cc:ffff:ffff:ffff:ffff:ffff:ffff
206ff5d:cd::/32ff5d:cd:ffff:ffff:ffff:ffff:ffff:ffff
207ff5d:ce::/32ff5d:ce:ffff:ffff:ffff:ffff:ffff:ffff
208ff5d:cf::/32ff5d:cf:ffff:ffff:ffff:ffff:ffff:ffff
209ff5d:d0::/32ff5d:d0:ffff:ffff:ffff:ffff:ffff:ffff
210ff5d:d1::/32ff5d:d1:ffff:ffff:ffff:ffff:ffff:ffff
211ff5d:d2::/32ff5d:d2:ffff:ffff:ffff:ffff:ffff:ffff
212ff5d:d3::/32ff5d:d3:ffff:ffff:ffff:ffff:ffff:ffff
213ff5d:d4::/32ff5d:d4:ffff:ffff:ffff:ffff:ffff:ffff
214ff5d:d5::/32ff5d:d5:ffff:ffff:ffff:ffff:ffff:ffff
215ff5d:d6::/32ff5d:d6:ffff:ffff:ffff:ffff:ffff:ffff
216ff5d:d7::/32ff5d:d7:ffff:ffff:ffff:ffff:ffff:ffff
217ff5d:d8::/32ff5d:d8:ffff:ffff:ffff:ffff:ffff:ffff
218ff5d:d9::/32ff5d:d9:ffff:ffff:ffff:ffff:ffff:ffff
219ff5d:da::/32ff5d:da:ffff:ffff:ffff:ffff:ffff:ffff
220ff5d:db::/32ff5d:db:ffff:ffff:ffff:ffff:ffff:ffff
221ff5d:dc::/32ff5d:dc:ffff:ffff:ffff:ffff:ffff:ffff
222ff5d:dd::/32ff5d:dd:ffff:ffff:ffff:ffff:ffff:ffff
223ff5d:de::/32ff5d:de:ffff:ffff:ffff:ffff:ffff:ffff
224ff5d:df::/32ff5d:df:ffff:ffff:ffff:ffff:ffff:ffff
225ff5d:e0::/32ff5d:e0:ffff:ffff:ffff:ffff:ffff:ffff
226ff5d:e1::/32ff5d:e1:ffff:ffff:ffff:ffff:ffff:ffff
227ff5d:e2::/32ff5d:e2:ffff:ffff:ffff:ffff:ffff:ffff
228ff5d:e3::/32ff5d:e3:ffff:ffff:ffff:ffff:ffff:ffff
229ff5d:e4::/32ff5d:e4:ffff:ffff:ffff:ffff:ffff:ffff
230ff5d:e5::/32ff5d:e5:ffff:ffff:ffff:ffff:ffff:ffff
231ff5d:e6::/32ff5d:e6:ffff:ffff:ffff:ffff:ffff:ffff
232ff5d:e7::/32ff5d:e7:ffff:ffff:ffff:ffff:ffff:ffff
233ff5d:e8::/32ff5d:e8:ffff:ffff:ffff:ffff:ffff:ffff
234ff5d:e9::/32ff5d:e9:ffff:ffff:ffff:ffff:ffff:ffff
235ff5d:ea::/32ff5d:ea:ffff:ffff:ffff:ffff:ffff:ffff
236ff5d:eb::/32ff5d:eb:ffff:ffff:ffff:ffff:ffff:ffff
237ff5d:ec::/32ff5d:ec:ffff:ffff:ffff:ffff:ffff:ffff
238ff5d:ed::/32ff5d:ed:ffff:ffff:ffff:ffff:ffff:ffff
239ff5d:ee::/32ff5d:ee:ffff:ffff:ffff:ffff:ffff:ffff
240ff5d:ef::/32ff5d:ef:ffff:ffff:ffff:ffff:ffff:ffff
241ff5d:f0::/32ff5d:f0:ffff:ffff:ffff:ffff:ffff:ffff
242ff5d:f1::/32ff5d:f1:ffff:ffff:ffff:ffff:ffff:ffff
243ff5d:f2::/32ff5d:f2:ffff:ffff:ffff:ffff:ffff:ffff
244ff5d:f3::/32ff5d:f3:ffff:ffff:ffff:ffff:ffff:ffff
245ff5d:f4::/32ff5d:f4:ffff:ffff:ffff:ffff:ffff:ffff
246ff5d:f5::/32ff5d:f5:ffff:ffff:ffff:ffff:ffff:ffff
247ff5d:f6::/32ff5d:f6:ffff:ffff:ffff:ffff:ffff:ffff
248ff5d:f7::/32ff5d:f7:ffff:ffff:ffff:ffff:ffff:ffff
249ff5d:f8::/32ff5d:f8:ffff:ffff:ffff:ffff:ffff:ffff
250ff5d:f9::/32ff5d:f9:ffff:ffff:ffff:ffff:ffff:ffff
251ff5d:fa::/32ff5d:fa:ffff:ffff:ffff:ffff:ffff:ffff
252ff5d:fb::/32ff5d:fb:ffff:ffff:ffff:ffff:ffff:ffff
253ff5d:fc::/32ff5d:fc:ffff:ffff:ffff:ffff:ffff:ffff
254ff5d:fd::/32ff5d:fd:ffff:ffff:ffff:ffff:ffff:ffff
255ff5d:fe::/32ff5d:fe:ffff:ffff:ffff:ffff:ffff:ffff
256ff5d:ff::/32ff5d:ff: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.