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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
ffce::/20
First address
ffce::
Last address
ffce:fff: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
ffce:0000:0000:0000:0000:0000:0000:0000
Type
Multicast ff00::/8
One-to-many traffic; replaces broadcast
Reverse DNS zone
0.e.c.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)

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

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