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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/20
Addresses2^108
/64 networks2^44
Network
ff05:c000::/20
First address
ff05:c000::
Last address
ff05:cfff:ffff:ffff:ffff:ffff:ffff:ffff
Addresses
324,518,553,658,426,726,783,156,020,576,256 (2^108)
/64 networks (LANs)
17,592,186,044,416 (2^44)
Full form
ff05:c000:0000:0000:0000:0000:0000:0000
Type
Multicast ff00::/8
One-to-many traffic; replaces broadcast
Reverse DNS zone
c.5.0.f.f.ip6.arpa
Split into smaller subnets/36
/21 (2)/22 (4)/23 (8)/24 (16)/28 (256)/32 (4,096)/36 (65,536)

ff05:c000::/20 makes 65,536 subnets of /36; the first 256 are listed.

Subnets
#SubnetLast address
1ff05:c000::/36ff05:c000:fff:ffff:ffff:ffff:ffff:ffff
2ff05:c000:1000::/36ff05:c000:1fff:ffff:ffff:ffff:ffff:ffff
3ff05:c000:2000::/36ff05:c000:2fff:ffff:ffff:ffff:ffff:ffff
4ff05:c000:3000::/36ff05:c000:3fff:ffff:ffff:ffff:ffff:ffff
5ff05:c000:4000::/36ff05:c000:4fff:ffff:ffff:ffff:ffff:ffff
6ff05:c000:5000::/36ff05:c000:5fff:ffff:ffff:ffff:ffff:ffff
7ff05:c000:6000::/36ff05:c000:6fff:ffff:ffff:ffff:ffff:ffff
8ff05:c000:7000::/36ff05:c000:7fff:ffff:ffff:ffff:ffff:ffff
9ff05:c000:8000::/36ff05:c000:8fff:ffff:ffff:ffff:ffff:ffff
10ff05:c000:9000::/36ff05:c000:9fff:ffff:ffff:ffff:ffff:ffff
11ff05:c000:a000::/36ff05:c000:afff:ffff:ffff:ffff:ffff:ffff
12ff05:c000:b000::/36ff05:c000:bfff:ffff:ffff:ffff:ffff:ffff
13ff05:c000:c000::/36ff05:c000:cfff:ffff:ffff:ffff:ffff:ffff
14ff05:c000:d000::/36ff05:c000:dfff:ffff:ffff:ffff:ffff:ffff
15ff05:c000:e000::/36ff05:c000:efff:ffff:ffff:ffff:ffff:ffff
16ff05:c000:f000::/36ff05:c000:ffff:ffff:ffff:ffff:ffff:ffff
17ff05:c001::/36ff05:c001:fff:ffff:ffff:ffff:ffff:ffff
18ff05:c001:1000::/36ff05:c001:1fff:ffff:ffff:ffff:ffff:ffff
19ff05:c001:2000::/36ff05:c001:2fff:ffff:ffff:ffff:ffff:ffff
20ff05:c001:3000::/36ff05:c001:3fff:ffff:ffff:ffff:ffff:ffff
21ff05:c001:4000::/36ff05:c001:4fff:ffff:ffff:ffff:ffff:ffff
22ff05:c001:5000::/36ff05:c001:5fff:ffff:ffff:ffff:ffff:ffff
23ff05:c001:6000::/36ff05:c001:6fff:ffff:ffff:ffff:ffff:ffff
24ff05:c001:7000::/36ff05:c001:7fff:ffff:ffff:ffff:ffff:ffff
25ff05:c001:8000::/36ff05:c001:8fff:ffff:ffff:ffff:ffff:ffff
26ff05:c001:9000::/36ff05:c001:9fff:ffff:ffff:ffff:ffff:ffff
27ff05:c001:a000::/36ff05:c001:afff:ffff:ffff:ffff:ffff:ffff
28ff05:c001:b000::/36ff05:c001:bfff:ffff:ffff:ffff:ffff:ffff
29ff05:c001:c000::/36ff05:c001:cfff:ffff:ffff:ffff:ffff:ffff
30ff05:c001:d000::/36ff05:c001:dfff:ffff:ffff:ffff:ffff:ffff
31ff05:c001:e000::/36ff05:c001:efff:ffff:ffff:ffff:ffff:ffff
32ff05:c001:f000::/36ff05:c001:ffff:ffff:ffff:ffff:ffff:ffff
33ff05:c002::/36ff05:c002:fff:ffff:ffff:ffff:ffff:ffff
34ff05:c002:1000::/36ff05:c002:1fff:ffff:ffff:ffff:ffff:ffff
35ff05:c002:2000::/36ff05:c002:2fff:ffff:ffff:ffff:ffff:ffff
36ff05:c002:3000::/36ff05:c002:3fff:ffff:ffff:ffff:ffff:ffff
37ff05:c002:4000::/36ff05:c002:4fff:ffff:ffff:ffff:ffff:ffff
38ff05:c002:5000::/36ff05:c002:5fff:ffff:ffff:ffff:ffff:ffff
39ff05:c002:6000::/36ff05:c002:6fff:ffff:ffff:ffff:ffff:ffff
40ff05:c002:7000::/36ff05:c002:7fff:ffff:ffff:ffff:ffff:ffff
41ff05:c002:8000::/36ff05:c002:8fff:ffff:ffff:ffff:ffff:ffff
42ff05:c002:9000::/36ff05:c002:9fff:ffff:ffff:ffff:ffff:ffff
43ff05:c002:a000::/36ff05:c002:afff:ffff:ffff:ffff:ffff:ffff
44ff05:c002:b000::/36ff05:c002:bfff:ffff:ffff:ffff:ffff:ffff
45ff05:c002:c000::/36ff05:c002:cfff:ffff:ffff:ffff:ffff:ffff
46ff05:c002:d000::/36ff05:c002:dfff:ffff:ffff:ffff:ffff:ffff
47ff05:c002:e000::/36ff05:c002:efff:ffff:ffff:ffff:ffff:ffff
48ff05:c002:f000::/36ff05:c002:ffff:ffff:ffff:ffff:ffff:ffff
49ff05:c003::/36ff05:c003:fff:ffff:ffff:ffff:ffff:ffff
50ff05:c003:1000::/36ff05:c003:1fff:ffff:ffff:ffff:ffff:ffff
51ff05:c003:2000::/36ff05:c003:2fff:ffff:ffff:ffff:ffff:ffff
52ff05:c003:3000::/36ff05:c003:3fff:ffff:ffff:ffff:ffff:ffff
53ff05:c003:4000::/36ff05:c003:4fff:ffff:ffff:ffff:ffff:ffff
54ff05:c003:5000::/36ff05:c003:5fff:ffff:ffff:ffff:ffff:ffff
55ff05:c003:6000::/36ff05:c003:6fff:ffff:ffff:ffff:ffff:ffff
56ff05:c003:7000::/36ff05:c003:7fff:ffff:ffff:ffff:ffff:ffff
57ff05:c003:8000::/36ff05:c003:8fff:ffff:ffff:ffff:ffff:ffff
58ff05:c003:9000::/36ff05:c003:9fff:ffff:ffff:ffff:ffff:ffff
59ff05:c003:a000::/36ff05:c003:afff:ffff:ffff:ffff:ffff:ffff
60ff05:c003:b000::/36ff05:c003:bfff:ffff:ffff:ffff:ffff:ffff
61ff05:c003:c000::/36ff05:c003:cfff:ffff:ffff:ffff:ffff:ffff
62ff05:c003:d000::/36ff05:c003:dfff:ffff:ffff:ffff:ffff:ffff
63ff05:c003:e000::/36ff05:c003:efff:ffff:ffff:ffff:ffff:ffff
64ff05:c003:f000::/36ff05:c003:ffff:ffff:ffff:ffff:ffff:ffff
65ff05:c004::/36ff05:c004:fff:ffff:ffff:ffff:ffff:ffff
66ff05:c004:1000::/36ff05:c004:1fff:ffff:ffff:ffff:ffff:ffff
67ff05:c004:2000::/36ff05:c004:2fff:ffff:ffff:ffff:ffff:ffff
68ff05:c004:3000::/36ff05:c004:3fff:ffff:ffff:ffff:ffff:ffff
69ff05:c004:4000::/36ff05:c004:4fff:ffff:ffff:ffff:ffff:ffff
70ff05:c004:5000::/36ff05:c004:5fff:ffff:ffff:ffff:ffff:ffff
71ff05:c004:6000::/36ff05:c004:6fff:ffff:ffff:ffff:ffff:ffff
72ff05:c004:7000::/36ff05:c004:7fff:ffff:ffff:ffff:ffff:ffff
73ff05:c004:8000::/36ff05:c004:8fff:ffff:ffff:ffff:ffff:ffff
74ff05:c004:9000::/36ff05:c004:9fff:ffff:ffff:ffff:ffff:ffff
75ff05:c004:a000::/36ff05:c004:afff:ffff:ffff:ffff:ffff:ffff
76ff05:c004:b000::/36ff05:c004:bfff:ffff:ffff:ffff:ffff:ffff
77ff05:c004:c000::/36ff05:c004:cfff:ffff:ffff:ffff:ffff:ffff
78ff05:c004:d000::/36ff05:c004:dfff:ffff:ffff:ffff:ffff:ffff
79ff05:c004:e000::/36ff05:c004:efff:ffff:ffff:ffff:ffff:ffff
80ff05:c004:f000::/36ff05:c004:ffff:ffff:ffff:ffff:ffff:ffff
81ff05:c005::/36ff05:c005:fff:ffff:ffff:ffff:ffff:ffff
82ff05:c005:1000::/36ff05:c005:1fff:ffff:ffff:ffff:ffff:ffff
83ff05:c005:2000::/36ff05:c005:2fff:ffff:ffff:ffff:ffff:ffff
84ff05:c005:3000::/36ff05:c005:3fff:ffff:ffff:ffff:ffff:ffff
85ff05:c005:4000::/36ff05:c005:4fff:ffff:ffff:ffff:ffff:ffff
86ff05:c005:5000::/36ff05:c005:5fff:ffff:ffff:ffff:ffff:ffff
87ff05:c005:6000::/36ff05:c005:6fff:ffff:ffff:ffff:ffff:ffff
88ff05:c005:7000::/36ff05:c005:7fff:ffff:ffff:ffff:ffff:ffff
89ff05:c005:8000::/36ff05:c005:8fff:ffff:ffff:ffff:ffff:ffff
90ff05:c005:9000::/36ff05:c005:9fff:ffff:ffff:ffff:ffff:ffff
91ff05:c005:a000::/36ff05:c005:afff:ffff:ffff:ffff:ffff:ffff
92ff05:c005:b000::/36ff05:c005:bfff:ffff:ffff:ffff:ffff:ffff
93ff05:c005:c000::/36ff05:c005:cfff:ffff:ffff:ffff:ffff:ffff
94ff05:c005:d000::/36ff05:c005:dfff:ffff:ffff:ffff:ffff:ffff
95ff05:c005:e000::/36ff05:c005:efff:ffff:ffff:ffff:ffff:ffff
96ff05:c005:f000::/36ff05:c005:ffff:ffff:ffff:ffff:ffff:ffff
97ff05:c006::/36ff05:c006:fff:ffff:ffff:ffff:ffff:ffff
98ff05:c006:1000::/36ff05:c006:1fff:ffff:ffff:ffff:ffff:ffff
99ff05:c006:2000::/36ff05:c006:2fff:ffff:ffff:ffff:ffff:ffff
100ff05:c006:3000::/36ff05:c006:3fff:ffff:ffff:ffff:ffff:ffff
101ff05:c006:4000::/36ff05:c006:4fff:ffff:ffff:ffff:ffff:ffff
102ff05:c006:5000::/36ff05:c006:5fff:ffff:ffff:ffff:ffff:ffff
103ff05:c006:6000::/36ff05:c006:6fff:ffff:ffff:ffff:ffff:ffff
104ff05:c006:7000::/36ff05:c006:7fff:ffff:ffff:ffff:ffff:ffff
105ff05:c006:8000::/36ff05:c006:8fff:ffff:ffff:ffff:ffff:ffff
106ff05:c006:9000::/36ff05:c006:9fff:ffff:ffff:ffff:ffff:ffff
107ff05:c006:a000::/36ff05:c006:afff:ffff:ffff:ffff:ffff:ffff
108ff05:c006:b000::/36ff05:c006:bfff:ffff:ffff:ffff:ffff:ffff
109ff05:c006:c000::/36ff05:c006:cfff:ffff:ffff:ffff:ffff:ffff
110ff05:c006:d000::/36ff05:c006:dfff:ffff:ffff:ffff:ffff:ffff
111ff05:c006:e000::/36ff05:c006:efff:ffff:ffff:ffff:ffff:ffff
112ff05:c006:f000::/36ff05:c006:ffff:ffff:ffff:ffff:ffff:ffff
113ff05:c007::/36ff05:c007:fff:ffff:ffff:ffff:ffff:ffff
114ff05:c007:1000::/36ff05:c007:1fff:ffff:ffff:ffff:ffff:ffff
115ff05:c007:2000::/36ff05:c007:2fff:ffff:ffff:ffff:ffff:ffff
116ff05:c007:3000::/36ff05:c007:3fff:ffff:ffff:ffff:ffff:ffff
117ff05:c007:4000::/36ff05:c007:4fff:ffff:ffff:ffff:ffff:ffff
118ff05:c007:5000::/36ff05:c007:5fff:ffff:ffff:ffff:ffff:ffff
119ff05:c007:6000::/36ff05:c007:6fff:ffff:ffff:ffff:ffff:ffff
120ff05:c007:7000::/36ff05:c007:7fff:ffff:ffff:ffff:ffff:ffff
121ff05:c007:8000::/36ff05:c007:8fff:ffff:ffff:ffff:ffff:ffff
122ff05:c007:9000::/36ff05:c007:9fff:ffff:ffff:ffff:ffff:ffff
123ff05:c007:a000::/36ff05:c007:afff:ffff:ffff:ffff:ffff:ffff
124ff05:c007:b000::/36ff05:c007:bfff:ffff:ffff:ffff:ffff:ffff
125ff05:c007:c000::/36ff05:c007:cfff:ffff:ffff:ffff:ffff:ffff
126ff05:c007:d000::/36ff05:c007:dfff:ffff:ffff:ffff:ffff:ffff
127ff05:c007:e000::/36ff05:c007:efff:ffff:ffff:ffff:ffff:ffff
128ff05:c007:f000::/36ff05:c007:ffff:ffff:ffff:ffff:ffff:ffff
129ff05:c008::/36ff05:c008:fff:ffff:ffff:ffff:ffff:ffff
130ff05:c008:1000::/36ff05:c008:1fff:ffff:ffff:ffff:ffff:ffff
131ff05:c008:2000::/36ff05:c008:2fff:ffff:ffff:ffff:ffff:ffff
132ff05:c008:3000::/36ff05:c008:3fff:ffff:ffff:ffff:ffff:ffff
133ff05:c008:4000::/36ff05:c008:4fff:ffff:ffff:ffff:ffff:ffff
134ff05:c008:5000::/36ff05:c008:5fff:ffff:ffff:ffff:ffff:ffff
135ff05:c008:6000::/36ff05:c008:6fff:ffff:ffff:ffff:ffff:ffff
136ff05:c008:7000::/36ff05:c008:7fff:ffff:ffff:ffff:ffff:ffff
137ff05:c008:8000::/36ff05:c008:8fff:ffff:ffff:ffff:ffff:ffff
138ff05:c008:9000::/36ff05:c008:9fff:ffff:ffff:ffff:ffff:ffff
139ff05:c008:a000::/36ff05:c008:afff:ffff:ffff:ffff:ffff:ffff
140ff05:c008:b000::/36ff05:c008:bfff:ffff:ffff:ffff:ffff:ffff
141ff05:c008:c000::/36ff05:c008:cfff:ffff:ffff:ffff:ffff:ffff
142ff05:c008:d000::/36ff05:c008:dfff:ffff:ffff:ffff:ffff:ffff
143ff05:c008:e000::/36ff05:c008:efff:ffff:ffff:ffff:ffff:ffff
144ff05:c008:f000::/36ff05:c008:ffff:ffff:ffff:ffff:ffff:ffff
145ff05:c009::/36ff05:c009:fff:ffff:ffff:ffff:ffff:ffff
146ff05:c009:1000::/36ff05:c009:1fff:ffff:ffff:ffff:ffff:ffff
147ff05:c009:2000::/36ff05:c009:2fff:ffff:ffff:ffff:ffff:ffff
148ff05:c009:3000::/36ff05:c009:3fff:ffff:ffff:ffff:ffff:ffff
149ff05:c009:4000::/36ff05:c009:4fff:ffff:ffff:ffff:ffff:ffff
150ff05:c009:5000::/36ff05:c009:5fff:ffff:ffff:ffff:ffff:ffff
151ff05:c009:6000::/36ff05:c009:6fff:ffff:ffff:ffff:ffff:ffff
152ff05:c009:7000::/36ff05:c009:7fff:ffff:ffff:ffff:ffff:ffff
153ff05:c009:8000::/36ff05:c009:8fff:ffff:ffff:ffff:ffff:ffff
154ff05:c009:9000::/36ff05:c009:9fff:ffff:ffff:ffff:ffff:ffff
155ff05:c009:a000::/36ff05:c009:afff:ffff:ffff:ffff:ffff:ffff
156ff05:c009:b000::/36ff05:c009:bfff:ffff:ffff:ffff:ffff:ffff
157ff05:c009:c000::/36ff05:c009:cfff:ffff:ffff:ffff:ffff:ffff
158ff05:c009:d000::/36ff05:c009:dfff:ffff:ffff:ffff:ffff:ffff
159ff05:c009:e000::/36ff05:c009:efff:ffff:ffff:ffff:ffff:ffff
160ff05:c009:f000::/36ff05:c009:ffff:ffff:ffff:ffff:ffff:ffff
161ff05:c00a::/36ff05:c00a:fff:ffff:ffff:ffff:ffff:ffff
162ff05:c00a:1000::/36ff05:c00a:1fff:ffff:ffff:ffff:ffff:ffff
163ff05:c00a:2000::/36ff05:c00a:2fff:ffff:ffff:ffff:ffff:ffff
164ff05:c00a:3000::/36ff05:c00a:3fff:ffff:ffff:ffff:ffff:ffff
165ff05:c00a:4000::/36ff05:c00a:4fff:ffff:ffff:ffff:ffff:ffff
166ff05:c00a:5000::/36ff05:c00a:5fff:ffff:ffff:ffff:ffff:ffff
167ff05:c00a:6000::/36ff05:c00a:6fff:ffff:ffff:ffff:ffff:ffff
168ff05:c00a:7000::/36ff05:c00a:7fff:ffff:ffff:ffff:ffff:ffff
169ff05:c00a:8000::/36ff05:c00a:8fff:ffff:ffff:ffff:ffff:ffff
170ff05:c00a:9000::/36ff05:c00a:9fff:ffff:ffff:ffff:ffff:ffff
171ff05:c00a:a000::/36ff05:c00a:afff:ffff:ffff:ffff:ffff:ffff
172ff05:c00a:b000::/36ff05:c00a:bfff:ffff:ffff:ffff:ffff:ffff
173ff05:c00a:c000::/36ff05:c00a:cfff:ffff:ffff:ffff:ffff:ffff
174ff05:c00a:d000::/36ff05:c00a:dfff:ffff:ffff:ffff:ffff:ffff
175ff05:c00a:e000::/36ff05:c00a:efff:ffff:ffff:ffff:ffff:ffff
176ff05:c00a:f000::/36ff05:c00a:ffff:ffff:ffff:ffff:ffff:ffff
177ff05:c00b::/36ff05:c00b:fff:ffff:ffff:ffff:ffff:ffff
178ff05:c00b:1000::/36ff05:c00b:1fff:ffff:ffff:ffff:ffff:ffff
179ff05:c00b:2000::/36ff05:c00b:2fff:ffff:ffff:ffff:ffff:ffff
180ff05:c00b:3000::/36ff05:c00b:3fff:ffff:ffff:ffff:ffff:ffff
181ff05:c00b:4000::/36ff05:c00b:4fff:ffff:ffff:ffff:ffff:ffff
182ff05:c00b:5000::/36ff05:c00b:5fff:ffff:ffff:ffff:ffff:ffff
183ff05:c00b:6000::/36ff05:c00b:6fff:ffff:ffff:ffff:ffff:ffff
184ff05:c00b:7000::/36ff05:c00b:7fff:ffff:ffff:ffff:ffff:ffff
185ff05:c00b:8000::/36ff05:c00b:8fff:ffff:ffff:ffff:ffff:ffff
186ff05:c00b:9000::/36ff05:c00b:9fff:ffff:ffff:ffff:ffff:ffff
187ff05:c00b:a000::/36ff05:c00b:afff:ffff:ffff:ffff:ffff:ffff
188ff05:c00b:b000::/36ff05:c00b:bfff:ffff:ffff:ffff:ffff:ffff
189ff05:c00b:c000::/36ff05:c00b:cfff:ffff:ffff:ffff:ffff:ffff
190ff05:c00b:d000::/36ff05:c00b:dfff:ffff:ffff:ffff:ffff:ffff
191ff05:c00b:e000::/36ff05:c00b:efff:ffff:ffff:ffff:ffff:ffff
192ff05:c00b:f000::/36ff05:c00b:ffff:ffff:ffff:ffff:ffff:ffff
193ff05:c00c::/36ff05:c00c:fff:ffff:ffff:ffff:ffff:ffff
194ff05:c00c:1000::/36ff05:c00c:1fff:ffff:ffff:ffff:ffff:ffff
195ff05:c00c:2000::/36ff05:c00c:2fff:ffff:ffff:ffff:ffff:ffff
196ff05:c00c:3000::/36ff05:c00c:3fff:ffff:ffff:ffff:ffff:ffff
197ff05:c00c:4000::/36ff05:c00c:4fff:ffff:ffff:ffff:ffff:ffff
198ff05:c00c:5000::/36ff05:c00c:5fff:ffff:ffff:ffff:ffff:ffff
199ff05:c00c:6000::/36ff05:c00c:6fff:ffff:ffff:ffff:ffff:ffff
200ff05:c00c:7000::/36ff05:c00c:7fff:ffff:ffff:ffff:ffff:ffff
201ff05:c00c:8000::/36ff05:c00c:8fff:ffff:ffff:ffff:ffff:ffff
202ff05:c00c:9000::/36ff05:c00c:9fff:ffff:ffff:ffff:ffff:ffff
203ff05:c00c:a000::/36ff05:c00c:afff:ffff:ffff:ffff:ffff:ffff
204ff05:c00c:b000::/36ff05:c00c:bfff:ffff:ffff:ffff:ffff:ffff
205ff05:c00c:c000::/36ff05:c00c:cfff:ffff:ffff:ffff:ffff:ffff
206ff05:c00c:d000::/36ff05:c00c:dfff:ffff:ffff:ffff:ffff:ffff
207ff05:c00c:e000::/36ff05:c00c:efff:ffff:ffff:ffff:ffff:ffff
208ff05:c00c:f000::/36ff05:c00c:ffff:ffff:ffff:ffff:ffff:ffff
209ff05:c00d::/36ff05:c00d:fff:ffff:ffff:ffff:ffff:ffff
210ff05:c00d:1000::/36ff05:c00d:1fff:ffff:ffff:ffff:ffff:ffff
211ff05:c00d:2000::/36ff05:c00d:2fff:ffff:ffff:ffff:ffff:ffff
212ff05:c00d:3000::/36ff05:c00d:3fff:ffff:ffff:ffff:ffff:ffff
213ff05:c00d:4000::/36ff05:c00d:4fff:ffff:ffff:ffff:ffff:ffff
214ff05:c00d:5000::/36ff05:c00d:5fff:ffff:ffff:ffff:ffff:ffff
215ff05:c00d:6000::/36ff05:c00d:6fff:ffff:ffff:ffff:ffff:ffff
216ff05:c00d:7000::/36ff05:c00d:7fff:ffff:ffff:ffff:ffff:ffff
217ff05:c00d:8000::/36ff05:c00d:8fff:ffff:ffff:ffff:ffff:ffff
218ff05:c00d:9000::/36ff05:c00d:9fff:ffff:ffff:ffff:ffff:ffff
219ff05:c00d:a000::/36ff05:c00d:afff:ffff:ffff:ffff:ffff:ffff
220ff05:c00d:b000::/36ff05:c00d:bfff:ffff:ffff:ffff:ffff:ffff
221ff05:c00d:c000::/36ff05:c00d:cfff:ffff:ffff:ffff:ffff:ffff
222ff05:c00d:d000::/36ff05:c00d:dfff:ffff:ffff:ffff:ffff:ffff
223ff05:c00d:e000::/36ff05:c00d:efff:ffff:ffff:ffff:ffff:ffff
224ff05:c00d:f000::/36ff05:c00d:ffff:ffff:ffff:ffff:ffff:ffff
225ff05:c00e::/36ff05:c00e:fff:ffff:ffff:ffff:ffff:ffff
226ff05:c00e:1000::/36ff05:c00e:1fff:ffff:ffff:ffff:ffff:ffff
227ff05:c00e:2000::/36ff05:c00e:2fff:ffff:ffff:ffff:ffff:ffff
228ff05:c00e:3000::/36ff05:c00e:3fff:ffff:ffff:ffff:ffff:ffff
229ff05:c00e:4000::/36ff05:c00e:4fff:ffff:ffff:ffff:ffff:ffff
230ff05:c00e:5000::/36ff05:c00e:5fff:ffff:ffff:ffff:ffff:ffff
231ff05:c00e:6000::/36ff05:c00e:6fff:ffff:ffff:ffff:ffff:ffff
232ff05:c00e:7000::/36ff05:c00e:7fff:ffff:ffff:ffff:ffff:ffff
233ff05:c00e:8000::/36ff05:c00e:8fff:ffff:ffff:ffff:ffff:ffff
234ff05:c00e:9000::/36ff05:c00e:9fff:ffff:ffff:ffff:ffff:ffff
235ff05:c00e:a000::/36ff05:c00e:afff:ffff:ffff:ffff:ffff:ffff
236ff05:c00e:b000::/36ff05:c00e:bfff:ffff:ffff:ffff:ffff:ffff
237ff05:c00e:c000::/36ff05:c00e:cfff:ffff:ffff:ffff:ffff:ffff
238ff05:c00e:d000::/36ff05:c00e:dfff:ffff:ffff:ffff:ffff:ffff
239ff05:c00e:e000::/36ff05:c00e:efff:ffff:ffff:ffff:ffff:ffff
240ff05:c00e:f000::/36ff05:c00e:ffff:ffff:ffff:ffff:ffff:ffff
241ff05:c00f::/36ff05:c00f:fff:ffff:ffff:ffff:ffff:ffff
242ff05:c00f:1000::/36ff05:c00f:1fff:ffff:ffff:ffff:ffff:ffff
243ff05:c00f:2000::/36ff05:c00f:2fff:ffff:ffff:ffff:ffff:ffff
244ff05:c00f:3000::/36ff05:c00f:3fff:ffff:ffff:ffff:ffff:ffff
245ff05:c00f:4000::/36ff05:c00f:4fff:ffff:ffff:ffff:ffff:ffff
246ff05:c00f:5000::/36ff05:c00f:5fff:ffff:ffff:ffff:ffff:ffff
247ff05:c00f:6000::/36ff05:c00f:6fff:ffff:ffff:ffff:ffff:ffff
248ff05:c00f:7000::/36ff05:c00f:7fff:ffff:ffff:ffff:ffff:ffff
249ff05:c00f:8000::/36ff05:c00f:8fff:ffff:ffff:ffff:ffff:ffff
250ff05:c00f:9000::/36ff05:c00f:9fff:ffff:ffff:ffff:ffff:ffff
251ff05:c00f:a000::/36ff05:c00f:afff:ffff:ffff:ffff:ffff:ffff
252ff05:c00f:b000::/36ff05:c00f:bfff:ffff:ffff:ffff:ffff:ffff
253ff05:c00f:c000::/36ff05:c00f:cfff:ffff:ffff:ffff:ffff:ffff
254ff05:c00f:d000::/36ff05:c00f:dfff:ffff:ffff:ffff:ffff:ffff
255ff05:c00f:e000::/36ff05:c00f:efff:ffff:ffff:ffff:ffff:ffff
256ff05:c00f:f000::/36ff05:c00f: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.