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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
ff03:5000::/20
First address
ff03:5000::
Last address
ff03:5fff: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
ff03:5000:0000:0000:0000:0000:0000:0000
Type
Multicast ff00::/8
One-to-many traffic; replaces broadcast
Reverse DNS zone
5.3.0.f.f.ip6.arpa
Split into smaller subnets/32
/21 (2)/22 (4)/23 (8)/24 (16)/28 (256)/32 (4,096)/36 (65,536)

ff03:5000::/20 makes 4,096 subnets of /32; the first 256 are listed.

Subnets
#SubnetLast address
1ff03:5000::/32ff03:5000:ffff:ffff:ffff:ffff:ffff:ffff
2ff03:5001::/32ff03:5001:ffff:ffff:ffff:ffff:ffff:ffff
3ff03:5002::/32ff03:5002:ffff:ffff:ffff:ffff:ffff:ffff
4ff03:5003::/32ff03:5003:ffff:ffff:ffff:ffff:ffff:ffff
5ff03:5004::/32ff03:5004:ffff:ffff:ffff:ffff:ffff:ffff
6ff03:5005::/32ff03:5005:ffff:ffff:ffff:ffff:ffff:ffff
7ff03:5006::/32ff03:5006:ffff:ffff:ffff:ffff:ffff:ffff
8ff03:5007::/32ff03:5007:ffff:ffff:ffff:ffff:ffff:ffff
9ff03:5008::/32ff03:5008:ffff:ffff:ffff:ffff:ffff:ffff
10ff03:5009::/32ff03:5009:ffff:ffff:ffff:ffff:ffff:ffff
11ff03:500a::/32ff03:500a:ffff:ffff:ffff:ffff:ffff:ffff
12ff03:500b::/32ff03:500b:ffff:ffff:ffff:ffff:ffff:ffff
13ff03:500c::/32ff03:500c:ffff:ffff:ffff:ffff:ffff:ffff
14ff03:500d::/32ff03:500d:ffff:ffff:ffff:ffff:ffff:ffff
15ff03:500e::/32ff03:500e:ffff:ffff:ffff:ffff:ffff:ffff
16ff03:500f::/32ff03:500f:ffff:ffff:ffff:ffff:ffff:ffff
17ff03:5010::/32ff03:5010:ffff:ffff:ffff:ffff:ffff:ffff
18ff03:5011::/32ff03:5011:ffff:ffff:ffff:ffff:ffff:ffff
19ff03:5012::/32ff03:5012:ffff:ffff:ffff:ffff:ffff:ffff
20ff03:5013::/32ff03:5013:ffff:ffff:ffff:ffff:ffff:ffff
21ff03:5014::/32ff03:5014:ffff:ffff:ffff:ffff:ffff:ffff
22ff03:5015::/32ff03:5015:ffff:ffff:ffff:ffff:ffff:ffff
23ff03:5016::/32ff03:5016:ffff:ffff:ffff:ffff:ffff:ffff
24ff03:5017::/32ff03:5017:ffff:ffff:ffff:ffff:ffff:ffff
25ff03:5018::/32ff03:5018:ffff:ffff:ffff:ffff:ffff:ffff
26ff03:5019::/32ff03:5019:ffff:ffff:ffff:ffff:ffff:ffff
27ff03:501a::/32ff03:501a:ffff:ffff:ffff:ffff:ffff:ffff
28ff03:501b::/32ff03:501b:ffff:ffff:ffff:ffff:ffff:ffff
29ff03:501c::/32ff03:501c:ffff:ffff:ffff:ffff:ffff:ffff
30ff03:501d::/32ff03:501d:ffff:ffff:ffff:ffff:ffff:ffff
31ff03:501e::/32ff03:501e:ffff:ffff:ffff:ffff:ffff:ffff
32ff03:501f::/32ff03:501f:ffff:ffff:ffff:ffff:ffff:ffff
33ff03:5020::/32ff03:5020:ffff:ffff:ffff:ffff:ffff:ffff
34ff03:5021::/32ff03:5021:ffff:ffff:ffff:ffff:ffff:ffff
35ff03:5022::/32ff03:5022:ffff:ffff:ffff:ffff:ffff:ffff
36ff03:5023::/32ff03:5023:ffff:ffff:ffff:ffff:ffff:ffff
37ff03:5024::/32ff03:5024:ffff:ffff:ffff:ffff:ffff:ffff
38ff03:5025::/32ff03:5025:ffff:ffff:ffff:ffff:ffff:ffff
39ff03:5026::/32ff03:5026:ffff:ffff:ffff:ffff:ffff:ffff
40ff03:5027::/32ff03:5027:ffff:ffff:ffff:ffff:ffff:ffff
41ff03:5028::/32ff03:5028:ffff:ffff:ffff:ffff:ffff:ffff
42ff03:5029::/32ff03:5029:ffff:ffff:ffff:ffff:ffff:ffff
43ff03:502a::/32ff03:502a:ffff:ffff:ffff:ffff:ffff:ffff
44ff03:502b::/32ff03:502b:ffff:ffff:ffff:ffff:ffff:ffff
45ff03:502c::/32ff03:502c:ffff:ffff:ffff:ffff:ffff:ffff
46ff03:502d::/32ff03:502d:ffff:ffff:ffff:ffff:ffff:ffff
47ff03:502e::/32ff03:502e:ffff:ffff:ffff:ffff:ffff:ffff
48ff03:502f::/32ff03:502f:ffff:ffff:ffff:ffff:ffff:ffff
49ff03:5030::/32ff03:5030:ffff:ffff:ffff:ffff:ffff:ffff
50ff03:5031::/32ff03:5031:ffff:ffff:ffff:ffff:ffff:ffff
51ff03:5032::/32ff03:5032:ffff:ffff:ffff:ffff:ffff:ffff
52ff03:5033::/32ff03:5033:ffff:ffff:ffff:ffff:ffff:ffff
53ff03:5034::/32ff03:5034:ffff:ffff:ffff:ffff:ffff:ffff
54ff03:5035::/32ff03:5035:ffff:ffff:ffff:ffff:ffff:ffff
55ff03:5036::/32ff03:5036:ffff:ffff:ffff:ffff:ffff:ffff
56ff03:5037::/32ff03:5037:ffff:ffff:ffff:ffff:ffff:ffff
57ff03:5038::/32ff03:5038:ffff:ffff:ffff:ffff:ffff:ffff
58ff03:5039::/32ff03:5039:ffff:ffff:ffff:ffff:ffff:ffff
59ff03:503a::/32ff03:503a:ffff:ffff:ffff:ffff:ffff:ffff
60ff03:503b::/32ff03:503b:ffff:ffff:ffff:ffff:ffff:ffff
61ff03:503c::/32ff03:503c:ffff:ffff:ffff:ffff:ffff:ffff
62ff03:503d::/32ff03:503d:ffff:ffff:ffff:ffff:ffff:ffff
63ff03:503e::/32ff03:503e:ffff:ffff:ffff:ffff:ffff:ffff
64ff03:503f::/32ff03:503f:ffff:ffff:ffff:ffff:ffff:ffff
65ff03:5040::/32ff03:5040:ffff:ffff:ffff:ffff:ffff:ffff
66ff03:5041::/32ff03:5041:ffff:ffff:ffff:ffff:ffff:ffff
67ff03:5042::/32ff03:5042:ffff:ffff:ffff:ffff:ffff:ffff
68ff03:5043::/32ff03:5043:ffff:ffff:ffff:ffff:ffff:ffff
69ff03:5044::/32ff03:5044:ffff:ffff:ffff:ffff:ffff:ffff
70ff03:5045::/32ff03:5045:ffff:ffff:ffff:ffff:ffff:ffff
71ff03:5046::/32ff03:5046:ffff:ffff:ffff:ffff:ffff:ffff
72ff03:5047::/32ff03:5047:ffff:ffff:ffff:ffff:ffff:ffff
73ff03:5048::/32ff03:5048:ffff:ffff:ffff:ffff:ffff:ffff
74ff03:5049::/32ff03:5049:ffff:ffff:ffff:ffff:ffff:ffff
75ff03:504a::/32ff03:504a:ffff:ffff:ffff:ffff:ffff:ffff
76ff03:504b::/32ff03:504b:ffff:ffff:ffff:ffff:ffff:ffff
77ff03:504c::/32ff03:504c:ffff:ffff:ffff:ffff:ffff:ffff
78ff03:504d::/32ff03:504d:ffff:ffff:ffff:ffff:ffff:ffff
79ff03:504e::/32ff03:504e:ffff:ffff:ffff:ffff:ffff:ffff
80ff03:504f::/32ff03:504f:ffff:ffff:ffff:ffff:ffff:ffff
81ff03:5050::/32ff03:5050:ffff:ffff:ffff:ffff:ffff:ffff
82ff03:5051::/32ff03:5051:ffff:ffff:ffff:ffff:ffff:ffff
83ff03:5052::/32ff03:5052:ffff:ffff:ffff:ffff:ffff:ffff
84ff03:5053::/32ff03:5053:ffff:ffff:ffff:ffff:ffff:ffff
85ff03:5054::/32ff03:5054:ffff:ffff:ffff:ffff:ffff:ffff
86ff03:5055::/32ff03:5055:ffff:ffff:ffff:ffff:ffff:ffff
87ff03:5056::/32ff03:5056:ffff:ffff:ffff:ffff:ffff:ffff
88ff03:5057::/32ff03:5057:ffff:ffff:ffff:ffff:ffff:ffff
89ff03:5058::/32ff03:5058:ffff:ffff:ffff:ffff:ffff:ffff
90ff03:5059::/32ff03:5059:ffff:ffff:ffff:ffff:ffff:ffff
91ff03:505a::/32ff03:505a:ffff:ffff:ffff:ffff:ffff:ffff
92ff03:505b::/32ff03:505b:ffff:ffff:ffff:ffff:ffff:ffff
93ff03:505c::/32ff03:505c:ffff:ffff:ffff:ffff:ffff:ffff
94ff03:505d::/32ff03:505d:ffff:ffff:ffff:ffff:ffff:ffff
95ff03:505e::/32ff03:505e:ffff:ffff:ffff:ffff:ffff:ffff
96ff03:505f::/32ff03:505f:ffff:ffff:ffff:ffff:ffff:ffff
97ff03:5060::/32ff03:5060:ffff:ffff:ffff:ffff:ffff:ffff
98ff03:5061::/32ff03:5061:ffff:ffff:ffff:ffff:ffff:ffff
99ff03:5062::/32ff03:5062:ffff:ffff:ffff:ffff:ffff:ffff
100ff03:5063::/32ff03:5063:ffff:ffff:ffff:ffff:ffff:ffff
101ff03:5064::/32ff03:5064:ffff:ffff:ffff:ffff:ffff:ffff
102ff03:5065::/32ff03:5065:ffff:ffff:ffff:ffff:ffff:ffff
103ff03:5066::/32ff03:5066:ffff:ffff:ffff:ffff:ffff:ffff
104ff03:5067::/32ff03:5067:ffff:ffff:ffff:ffff:ffff:ffff
105ff03:5068::/32ff03:5068:ffff:ffff:ffff:ffff:ffff:ffff
106ff03:5069::/32ff03:5069:ffff:ffff:ffff:ffff:ffff:ffff
107ff03:506a::/32ff03:506a:ffff:ffff:ffff:ffff:ffff:ffff
108ff03:506b::/32ff03:506b:ffff:ffff:ffff:ffff:ffff:ffff
109ff03:506c::/32ff03:506c:ffff:ffff:ffff:ffff:ffff:ffff
110ff03:506d::/32ff03:506d:ffff:ffff:ffff:ffff:ffff:ffff
111ff03:506e::/32ff03:506e:ffff:ffff:ffff:ffff:ffff:ffff
112ff03:506f::/32ff03:506f:ffff:ffff:ffff:ffff:ffff:ffff
113ff03:5070::/32ff03:5070:ffff:ffff:ffff:ffff:ffff:ffff
114ff03:5071::/32ff03:5071:ffff:ffff:ffff:ffff:ffff:ffff
115ff03:5072::/32ff03:5072:ffff:ffff:ffff:ffff:ffff:ffff
116ff03:5073::/32ff03:5073:ffff:ffff:ffff:ffff:ffff:ffff
117ff03:5074::/32ff03:5074:ffff:ffff:ffff:ffff:ffff:ffff
118ff03:5075::/32ff03:5075:ffff:ffff:ffff:ffff:ffff:ffff
119ff03:5076::/32ff03:5076:ffff:ffff:ffff:ffff:ffff:ffff
120ff03:5077::/32ff03:5077:ffff:ffff:ffff:ffff:ffff:ffff
121ff03:5078::/32ff03:5078:ffff:ffff:ffff:ffff:ffff:ffff
122ff03:5079::/32ff03:5079:ffff:ffff:ffff:ffff:ffff:ffff
123ff03:507a::/32ff03:507a:ffff:ffff:ffff:ffff:ffff:ffff
124ff03:507b::/32ff03:507b:ffff:ffff:ffff:ffff:ffff:ffff
125ff03:507c::/32ff03:507c:ffff:ffff:ffff:ffff:ffff:ffff
126ff03:507d::/32ff03:507d:ffff:ffff:ffff:ffff:ffff:ffff
127ff03:507e::/32ff03:507e:ffff:ffff:ffff:ffff:ffff:ffff
128ff03:507f::/32ff03:507f:ffff:ffff:ffff:ffff:ffff:ffff
129ff03:5080::/32ff03:5080:ffff:ffff:ffff:ffff:ffff:ffff
130ff03:5081::/32ff03:5081:ffff:ffff:ffff:ffff:ffff:ffff
131ff03:5082::/32ff03:5082:ffff:ffff:ffff:ffff:ffff:ffff
132ff03:5083::/32ff03:5083:ffff:ffff:ffff:ffff:ffff:ffff
133ff03:5084::/32ff03:5084:ffff:ffff:ffff:ffff:ffff:ffff
134ff03:5085::/32ff03:5085:ffff:ffff:ffff:ffff:ffff:ffff
135ff03:5086::/32ff03:5086:ffff:ffff:ffff:ffff:ffff:ffff
136ff03:5087::/32ff03:5087:ffff:ffff:ffff:ffff:ffff:ffff
137ff03:5088::/32ff03:5088:ffff:ffff:ffff:ffff:ffff:ffff
138ff03:5089::/32ff03:5089:ffff:ffff:ffff:ffff:ffff:ffff
139ff03:508a::/32ff03:508a:ffff:ffff:ffff:ffff:ffff:ffff
140ff03:508b::/32ff03:508b:ffff:ffff:ffff:ffff:ffff:ffff
141ff03:508c::/32ff03:508c:ffff:ffff:ffff:ffff:ffff:ffff
142ff03:508d::/32ff03:508d:ffff:ffff:ffff:ffff:ffff:ffff
143ff03:508e::/32ff03:508e:ffff:ffff:ffff:ffff:ffff:ffff
144ff03:508f::/32ff03:508f:ffff:ffff:ffff:ffff:ffff:ffff
145ff03:5090::/32ff03:5090:ffff:ffff:ffff:ffff:ffff:ffff
146ff03:5091::/32ff03:5091:ffff:ffff:ffff:ffff:ffff:ffff
147ff03:5092::/32ff03:5092:ffff:ffff:ffff:ffff:ffff:ffff
148ff03:5093::/32ff03:5093:ffff:ffff:ffff:ffff:ffff:ffff
149ff03:5094::/32ff03:5094:ffff:ffff:ffff:ffff:ffff:ffff
150ff03:5095::/32ff03:5095:ffff:ffff:ffff:ffff:ffff:ffff
151ff03:5096::/32ff03:5096:ffff:ffff:ffff:ffff:ffff:ffff
152ff03:5097::/32ff03:5097:ffff:ffff:ffff:ffff:ffff:ffff
153ff03:5098::/32ff03:5098:ffff:ffff:ffff:ffff:ffff:ffff
154ff03:5099::/32ff03:5099:ffff:ffff:ffff:ffff:ffff:ffff
155ff03:509a::/32ff03:509a:ffff:ffff:ffff:ffff:ffff:ffff
156ff03:509b::/32ff03:509b:ffff:ffff:ffff:ffff:ffff:ffff
157ff03:509c::/32ff03:509c:ffff:ffff:ffff:ffff:ffff:ffff
158ff03:509d::/32ff03:509d:ffff:ffff:ffff:ffff:ffff:ffff
159ff03:509e::/32ff03:509e:ffff:ffff:ffff:ffff:ffff:ffff
160ff03:509f::/32ff03:509f:ffff:ffff:ffff:ffff:ffff:ffff
161ff03:50a0::/32ff03:50a0:ffff:ffff:ffff:ffff:ffff:ffff
162ff03:50a1::/32ff03:50a1:ffff:ffff:ffff:ffff:ffff:ffff
163ff03:50a2::/32ff03:50a2:ffff:ffff:ffff:ffff:ffff:ffff
164ff03:50a3::/32ff03:50a3:ffff:ffff:ffff:ffff:ffff:ffff
165ff03:50a4::/32ff03:50a4:ffff:ffff:ffff:ffff:ffff:ffff
166ff03:50a5::/32ff03:50a5:ffff:ffff:ffff:ffff:ffff:ffff
167ff03:50a6::/32ff03:50a6:ffff:ffff:ffff:ffff:ffff:ffff
168ff03:50a7::/32ff03:50a7:ffff:ffff:ffff:ffff:ffff:ffff
169ff03:50a8::/32ff03:50a8:ffff:ffff:ffff:ffff:ffff:ffff
170ff03:50a9::/32ff03:50a9:ffff:ffff:ffff:ffff:ffff:ffff
171ff03:50aa::/32ff03:50aa:ffff:ffff:ffff:ffff:ffff:ffff
172ff03:50ab::/32ff03:50ab:ffff:ffff:ffff:ffff:ffff:ffff
173ff03:50ac::/32ff03:50ac:ffff:ffff:ffff:ffff:ffff:ffff
174ff03:50ad::/32ff03:50ad:ffff:ffff:ffff:ffff:ffff:ffff
175ff03:50ae::/32ff03:50ae:ffff:ffff:ffff:ffff:ffff:ffff
176ff03:50af::/32ff03:50af:ffff:ffff:ffff:ffff:ffff:ffff
177ff03:50b0::/32ff03:50b0:ffff:ffff:ffff:ffff:ffff:ffff
178ff03:50b1::/32ff03:50b1:ffff:ffff:ffff:ffff:ffff:ffff
179ff03:50b2::/32ff03:50b2:ffff:ffff:ffff:ffff:ffff:ffff
180ff03:50b3::/32ff03:50b3:ffff:ffff:ffff:ffff:ffff:ffff
181ff03:50b4::/32ff03:50b4:ffff:ffff:ffff:ffff:ffff:ffff
182ff03:50b5::/32ff03:50b5:ffff:ffff:ffff:ffff:ffff:ffff
183ff03:50b6::/32ff03:50b6:ffff:ffff:ffff:ffff:ffff:ffff
184ff03:50b7::/32ff03:50b7:ffff:ffff:ffff:ffff:ffff:ffff
185ff03:50b8::/32ff03:50b8:ffff:ffff:ffff:ffff:ffff:ffff
186ff03:50b9::/32ff03:50b9:ffff:ffff:ffff:ffff:ffff:ffff
187ff03:50ba::/32ff03:50ba:ffff:ffff:ffff:ffff:ffff:ffff
188ff03:50bb::/32ff03:50bb:ffff:ffff:ffff:ffff:ffff:ffff
189ff03:50bc::/32ff03:50bc:ffff:ffff:ffff:ffff:ffff:ffff
190ff03:50bd::/32ff03:50bd:ffff:ffff:ffff:ffff:ffff:ffff
191ff03:50be::/32ff03:50be:ffff:ffff:ffff:ffff:ffff:ffff
192ff03:50bf::/32ff03:50bf:ffff:ffff:ffff:ffff:ffff:ffff
193ff03:50c0::/32ff03:50c0:ffff:ffff:ffff:ffff:ffff:ffff
194ff03:50c1::/32ff03:50c1:ffff:ffff:ffff:ffff:ffff:ffff
195ff03:50c2::/32ff03:50c2:ffff:ffff:ffff:ffff:ffff:ffff
196ff03:50c3::/32ff03:50c3:ffff:ffff:ffff:ffff:ffff:ffff
197ff03:50c4::/32ff03:50c4:ffff:ffff:ffff:ffff:ffff:ffff
198ff03:50c5::/32ff03:50c5:ffff:ffff:ffff:ffff:ffff:ffff
199ff03:50c6::/32ff03:50c6:ffff:ffff:ffff:ffff:ffff:ffff
200ff03:50c7::/32ff03:50c7:ffff:ffff:ffff:ffff:ffff:ffff
201ff03:50c8::/32ff03:50c8:ffff:ffff:ffff:ffff:ffff:ffff
202ff03:50c9::/32ff03:50c9:ffff:ffff:ffff:ffff:ffff:ffff
203ff03:50ca::/32ff03:50ca:ffff:ffff:ffff:ffff:ffff:ffff
204ff03:50cb::/32ff03:50cb:ffff:ffff:ffff:ffff:ffff:ffff
205ff03:50cc::/32ff03:50cc:ffff:ffff:ffff:ffff:ffff:ffff
206ff03:50cd::/32ff03:50cd:ffff:ffff:ffff:ffff:ffff:ffff
207ff03:50ce::/32ff03:50ce:ffff:ffff:ffff:ffff:ffff:ffff
208ff03:50cf::/32ff03:50cf:ffff:ffff:ffff:ffff:ffff:ffff
209ff03:50d0::/32ff03:50d0:ffff:ffff:ffff:ffff:ffff:ffff
210ff03:50d1::/32ff03:50d1:ffff:ffff:ffff:ffff:ffff:ffff
211ff03:50d2::/32ff03:50d2:ffff:ffff:ffff:ffff:ffff:ffff
212ff03:50d3::/32ff03:50d3:ffff:ffff:ffff:ffff:ffff:ffff
213ff03:50d4::/32ff03:50d4:ffff:ffff:ffff:ffff:ffff:ffff
214ff03:50d5::/32ff03:50d5:ffff:ffff:ffff:ffff:ffff:ffff
215ff03:50d6::/32ff03:50d6:ffff:ffff:ffff:ffff:ffff:ffff
216ff03:50d7::/32ff03:50d7:ffff:ffff:ffff:ffff:ffff:ffff
217ff03:50d8::/32ff03:50d8:ffff:ffff:ffff:ffff:ffff:ffff
218ff03:50d9::/32ff03:50d9:ffff:ffff:ffff:ffff:ffff:ffff
219ff03:50da::/32ff03:50da:ffff:ffff:ffff:ffff:ffff:ffff
220ff03:50db::/32ff03:50db:ffff:ffff:ffff:ffff:ffff:ffff
221ff03:50dc::/32ff03:50dc:ffff:ffff:ffff:ffff:ffff:ffff
222ff03:50dd::/32ff03:50dd:ffff:ffff:ffff:ffff:ffff:ffff
223ff03:50de::/32ff03:50de:ffff:ffff:ffff:ffff:ffff:ffff
224ff03:50df::/32ff03:50df:ffff:ffff:ffff:ffff:ffff:ffff
225ff03:50e0::/32ff03:50e0:ffff:ffff:ffff:ffff:ffff:ffff
226ff03:50e1::/32ff03:50e1:ffff:ffff:ffff:ffff:ffff:ffff
227ff03:50e2::/32ff03:50e2:ffff:ffff:ffff:ffff:ffff:ffff
228ff03:50e3::/32ff03:50e3:ffff:ffff:ffff:ffff:ffff:ffff
229ff03:50e4::/32ff03:50e4:ffff:ffff:ffff:ffff:ffff:ffff
230ff03:50e5::/32ff03:50e5:ffff:ffff:ffff:ffff:ffff:ffff
231ff03:50e6::/32ff03:50e6:ffff:ffff:ffff:ffff:ffff:ffff
232ff03:50e7::/32ff03:50e7:ffff:ffff:ffff:ffff:ffff:ffff
233ff03:50e8::/32ff03:50e8:ffff:ffff:ffff:ffff:ffff:ffff
234ff03:50e9::/32ff03:50e9:ffff:ffff:ffff:ffff:ffff:ffff
235ff03:50ea::/32ff03:50ea:ffff:ffff:ffff:ffff:ffff:ffff
236ff03:50eb::/32ff03:50eb:ffff:ffff:ffff:ffff:ffff:ffff
237ff03:50ec::/32ff03:50ec:ffff:ffff:ffff:ffff:ffff:ffff
238ff03:50ed::/32ff03:50ed:ffff:ffff:ffff:ffff:ffff:ffff
239ff03:50ee::/32ff03:50ee:ffff:ffff:ffff:ffff:ffff:ffff
240ff03:50ef::/32ff03:50ef:ffff:ffff:ffff:ffff:ffff:ffff
241ff03:50f0::/32ff03:50f0:ffff:ffff:ffff:ffff:ffff:ffff
242ff03:50f1::/32ff03:50f1:ffff:ffff:ffff:ffff:ffff:ffff
243ff03:50f2::/32ff03:50f2:ffff:ffff:ffff:ffff:ffff:ffff
244ff03:50f3::/32ff03:50f3:ffff:ffff:ffff:ffff:ffff:ffff
245ff03:50f4::/32ff03:50f4:ffff:ffff:ffff:ffff:ffff:ffff
246ff03:50f5::/32ff03:50f5:ffff:ffff:ffff:ffff:ffff:ffff
247ff03:50f6::/32ff03:50f6:ffff:ffff:ffff:ffff:ffff:ffff
248ff03:50f7::/32ff03:50f7:ffff:ffff:ffff:ffff:ffff:ffff
249ff03:50f8::/32ff03:50f8:ffff:ffff:ffff:ffff:ffff:ffff
250ff03:50f9::/32ff03:50f9:ffff:ffff:ffff:ffff:ffff:ffff
251ff03:50fa::/32ff03:50fa:ffff:ffff:ffff:ffff:ffff:ffff
252ff03:50fb::/32ff03:50fb:ffff:ffff:ffff:ffff:ffff:ffff
253ff03:50fc::/32ff03:50fc:ffff:ffff:ffff:ffff:ffff:ffff
254ff03:50fd::/32ff03:50fd:ffff:ffff:ffff:ffff:ffff:ffff
255ff03:50fe::/32ff03:50fe:ffff:ffff:ffff:ffff:ffff:ffff
256ff03:50ff::/32ff03:50ff: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.