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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
fc83::/20
First address
fc83::
Last address
fc83: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
fc83:0000:0000:0000:0000:0000:0000:0000
Type
Unique local (ULA) fc00::/7
Private IPv6, like RFC 1918; usually fd00::/8
Reverse DNS zone
0.3.8.c.f.ip6.arpa
Split into smaller subnets/32
/21 (2)/22 (4)/23 (8)/24 (16)/28 (256)/32 (4,096)/36 (65,536)

fc83::/20 makes 4,096 subnets of /32; the first 256 are listed.

Subnets
#SubnetLast address
1fc83::/32fc83:0:ffff:ffff:ffff:ffff:ffff:ffff
2fc83:1::/32fc83:1:ffff:ffff:ffff:ffff:ffff:ffff
3fc83:2::/32fc83:2:ffff:ffff:ffff:ffff:ffff:ffff
4fc83:3::/32fc83:3:ffff:ffff:ffff:ffff:ffff:ffff
5fc83:4::/32fc83:4:ffff:ffff:ffff:ffff:ffff:ffff
6fc83:5::/32fc83:5:ffff:ffff:ffff:ffff:ffff:ffff
7fc83:6::/32fc83:6:ffff:ffff:ffff:ffff:ffff:ffff
8fc83:7::/32fc83:7:ffff:ffff:ffff:ffff:ffff:ffff
9fc83:8::/32fc83:8:ffff:ffff:ffff:ffff:ffff:ffff
10fc83:9::/32fc83:9:ffff:ffff:ffff:ffff:ffff:ffff
11fc83:a::/32fc83:a:ffff:ffff:ffff:ffff:ffff:ffff
12fc83:b::/32fc83:b:ffff:ffff:ffff:ffff:ffff:ffff
13fc83:c::/32fc83:c:ffff:ffff:ffff:ffff:ffff:ffff
14fc83:d::/32fc83:d:ffff:ffff:ffff:ffff:ffff:ffff
15fc83:e::/32fc83:e:ffff:ffff:ffff:ffff:ffff:ffff
16fc83:f::/32fc83:f:ffff:ffff:ffff:ffff:ffff:ffff
17fc83:10::/32fc83:10:ffff:ffff:ffff:ffff:ffff:ffff
18fc83:11::/32fc83:11:ffff:ffff:ffff:ffff:ffff:ffff
19fc83:12::/32fc83:12:ffff:ffff:ffff:ffff:ffff:ffff
20fc83:13::/32fc83:13:ffff:ffff:ffff:ffff:ffff:ffff
21fc83:14::/32fc83:14:ffff:ffff:ffff:ffff:ffff:ffff
22fc83:15::/32fc83:15:ffff:ffff:ffff:ffff:ffff:ffff
23fc83:16::/32fc83:16:ffff:ffff:ffff:ffff:ffff:ffff
24fc83:17::/32fc83:17:ffff:ffff:ffff:ffff:ffff:ffff
25fc83:18::/32fc83:18:ffff:ffff:ffff:ffff:ffff:ffff
26fc83:19::/32fc83:19:ffff:ffff:ffff:ffff:ffff:ffff
27fc83:1a::/32fc83:1a:ffff:ffff:ffff:ffff:ffff:ffff
28fc83:1b::/32fc83:1b:ffff:ffff:ffff:ffff:ffff:ffff
29fc83:1c::/32fc83:1c:ffff:ffff:ffff:ffff:ffff:ffff
30fc83:1d::/32fc83:1d:ffff:ffff:ffff:ffff:ffff:ffff
31fc83:1e::/32fc83:1e:ffff:ffff:ffff:ffff:ffff:ffff
32fc83:1f::/32fc83:1f:ffff:ffff:ffff:ffff:ffff:ffff
33fc83:20::/32fc83:20:ffff:ffff:ffff:ffff:ffff:ffff
34fc83:21::/32fc83:21:ffff:ffff:ffff:ffff:ffff:ffff
35fc83:22::/32fc83:22:ffff:ffff:ffff:ffff:ffff:ffff
36fc83:23::/32fc83:23:ffff:ffff:ffff:ffff:ffff:ffff
37fc83:24::/32fc83:24:ffff:ffff:ffff:ffff:ffff:ffff
38fc83:25::/32fc83:25:ffff:ffff:ffff:ffff:ffff:ffff
39fc83:26::/32fc83:26:ffff:ffff:ffff:ffff:ffff:ffff
40fc83:27::/32fc83:27:ffff:ffff:ffff:ffff:ffff:ffff
41fc83:28::/32fc83:28:ffff:ffff:ffff:ffff:ffff:ffff
42fc83:29::/32fc83:29:ffff:ffff:ffff:ffff:ffff:ffff
43fc83:2a::/32fc83:2a:ffff:ffff:ffff:ffff:ffff:ffff
44fc83:2b::/32fc83:2b:ffff:ffff:ffff:ffff:ffff:ffff
45fc83:2c::/32fc83:2c:ffff:ffff:ffff:ffff:ffff:ffff
46fc83:2d::/32fc83:2d:ffff:ffff:ffff:ffff:ffff:ffff
47fc83:2e::/32fc83:2e:ffff:ffff:ffff:ffff:ffff:ffff
48fc83:2f::/32fc83:2f:ffff:ffff:ffff:ffff:ffff:ffff
49fc83:30::/32fc83:30:ffff:ffff:ffff:ffff:ffff:ffff
50fc83:31::/32fc83:31:ffff:ffff:ffff:ffff:ffff:ffff
51fc83:32::/32fc83:32:ffff:ffff:ffff:ffff:ffff:ffff
52fc83:33::/32fc83:33:ffff:ffff:ffff:ffff:ffff:ffff
53fc83:34::/32fc83:34:ffff:ffff:ffff:ffff:ffff:ffff
54fc83:35::/32fc83:35:ffff:ffff:ffff:ffff:ffff:ffff
55fc83:36::/32fc83:36:ffff:ffff:ffff:ffff:ffff:ffff
56fc83:37::/32fc83:37:ffff:ffff:ffff:ffff:ffff:ffff
57fc83:38::/32fc83:38:ffff:ffff:ffff:ffff:ffff:ffff
58fc83:39::/32fc83:39:ffff:ffff:ffff:ffff:ffff:ffff
59fc83:3a::/32fc83:3a:ffff:ffff:ffff:ffff:ffff:ffff
60fc83:3b::/32fc83:3b:ffff:ffff:ffff:ffff:ffff:ffff
61fc83:3c::/32fc83:3c:ffff:ffff:ffff:ffff:ffff:ffff
62fc83:3d::/32fc83:3d:ffff:ffff:ffff:ffff:ffff:ffff
63fc83:3e::/32fc83:3e:ffff:ffff:ffff:ffff:ffff:ffff
64fc83:3f::/32fc83:3f:ffff:ffff:ffff:ffff:ffff:ffff
65fc83:40::/32fc83:40:ffff:ffff:ffff:ffff:ffff:ffff
66fc83:41::/32fc83:41:ffff:ffff:ffff:ffff:ffff:ffff
67fc83:42::/32fc83:42:ffff:ffff:ffff:ffff:ffff:ffff
68fc83:43::/32fc83:43:ffff:ffff:ffff:ffff:ffff:ffff
69fc83:44::/32fc83:44:ffff:ffff:ffff:ffff:ffff:ffff
70fc83:45::/32fc83:45:ffff:ffff:ffff:ffff:ffff:ffff
71fc83:46::/32fc83:46:ffff:ffff:ffff:ffff:ffff:ffff
72fc83:47::/32fc83:47:ffff:ffff:ffff:ffff:ffff:ffff
73fc83:48::/32fc83:48:ffff:ffff:ffff:ffff:ffff:ffff
74fc83:49::/32fc83:49:ffff:ffff:ffff:ffff:ffff:ffff
75fc83:4a::/32fc83:4a:ffff:ffff:ffff:ffff:ffff:ffff
76fc83:4b::/32fc83:4b:ffff:ffff:ffff:ffff:ffff:ffff
77fc83:4c::/32fc83:4c:ffff:ffff:ffff:ffff:ffff:ffff
78fc83:4d::/32fc83:4d:ffff:ffff:ffff:ffff:ffff:ffff
79fc83:4e::/32fc83:4e:ffff:ffff:ffff:ffff:ffff:ffff
80fc83:4f::/32fc83:4f:ffff:ffff:ffff:ffff:ffff:ffff
81fc83:50::/32fc83:50:ffff:ffff:ffff:ffff:ffff:ffff
82fc83:51::/32fc83:51:ffff:ffff:ffff:ffff:ffff:ffff
83fc83:52::/32fc83:52:ffff:ffff:ffff:ffff:ffff:ffff
84fc83:53::/32fc83:53:ffff:ffff:ffff:ffff:ffff:ffff
85fc83:54::/32fc83:54:ffff:ffff:ffff:ffff:ffff:ffff
86fc83:55::/32fc83:55:ffff:ffff:ffff:ffff:ffff:ffff
87fc83:56::/32fc83:56:ffff:ffff:ffff:ffff:ffff:ffff
88fc83:57::/32fc83:57:ffff:ffff:ffff:ffff:ffff:ffff
89fc83:58::/32fc83:58:ffff:ffff:ffff:ffff:ffff:ffff
90fc83:59::/32fc83:59:ffff:ffff:ffff:ffff:ffff:ffff
91fc83:5a::/32fc83:5a:ffff:ffff:ffff:ffff:ffff:ffff
92fc83:5b::/32fc83:5b:ffff:ffff:ffff:ffff:ffff:ffff
93fc83:5c::/32fc83:5c:ffff:ffff:ffff:ffff:ffff:ffff
94fc83:5d::/32fc83:5d:ffff:ffff:ffff:ffff:ffff:ffff
95fc83:5e::/32fc83:5e:ffff:ffff:ffff:ffff:ffff:ffff
96fc83:5f::/32fc83:5f:ffff:ffff:ffff:ffff:ffff:ffff
97fc83:60::/32fc83:60:ffff:ffff:ffff:ffff:ffff:ffff
98fc83:61::/32fc83:61:ffff:ffff:ffff:ffff:ffff:ffff
99fc83:62::/32fc83:62:ffff:ffff:ffff:ffff:ffff:ffff
100fc83:63::/32fc83:63:ffff:ffff:ffff:ffff:ffff:ffff
101fc83:64::/32fc83:64:ffff:ffff:ffff:ffff:ffff:ffff
102fc83:65::/32fc83:65:ffff:ffff:ffff:ffff:ffff:ffff
103fc83:66::/32fc83:66:ffff:ffff:ffff:ffff:ffff:ffff
104fc83:67::/32fc83:67:ffff:ffff:ffff:ffff:ffff:ffff
105fc83:68::/32fc83:68:ffff:ffff:ffff:ffff:ffff:ffff
106fc83:69::/32fc83:69:ffff:ffff:ffff:ffff:ffff:ffff
107fc83:6a::/32fc83:6a:ffff:ffff:ffff:ffff:ffff:ffff
108fc83:6b::/32fc83:6b:ffff:ffff:ffff:ffff:ffff:ffff
109fc83:6c::/32fc83:6c:ffff:ffff:ffff:ffff:ffff:ffff
110fc83:6d::/32fc83:6d:ffff:ffff:ffff:ffff:ffff:ffff
111fc83:6e::/32fc83:6e:ffff:ffff:ffff:ffff:ffff:ffff
112fc83:6f::/32fc83:6f:ffff:ffff:ffff:ffff:ffff:ffff
113fc83:70::/32fc83:70:ffff:ffff:ffff:ffff:ffff:ffff
114fc83:71::/32fc83:71:ffff:ffff:ffff:ffff:ffff:ffff
115fc83:72::/32fc83:72:ffff:ffff:ffff:ffff:ffff:ffff
116fc83:73::/32fc83:73:ffff:ffff:ffff:ffff:ffff:ffff
117fc83:74::/32fc83:74:ffff:ffff:ffff:ffff:ffff:ffff
118fc83:75::/32fc83:75:ffff:ffff:ffff:ffff:ffff:ffff
119fc83:76::/32fc83:76:ffff:ffff:ffff:ffff:ffff:ffff
120fc83:77::/32fc83:77:ffff:ffff:ffff:ffff:ffff:ffff
121fc83:78::/32fc83:78:ffff:ffff:ffff:ffff:ffff:ffff
122fc83:79::/32fc83:79:ffff:ffff:ffff:ffff:ffff:ffff
123fc83:7a::/32fc83:7a:ffff:ffff:ffff:ffff:ffff:ffff
124fc83:7b::/32fc83:7b:ffff:ffff:ffff:ffff:ffff:ffff
125fc83:7c::/32fc83:7c:ffff:ffff:ffff:ffff:ffff:ffff
126fc83:7d::/32fc83:7d:ffff:ffff:ffff:ffff:ffff:ffff
127fc83:7e::/32fc83:7e:ffff:ffff:ffff:ffff:ffff:ffff
128fc83:7f::/32fc83:7f:ffff:ffff:ffff:ffff:ffff:ffff
129fc83:80::/32fc83:80:ffff:ffff:ffff:ffff:ffff:ffff
130fc83:81::/32fc83:81:ffff:ffff:ffff:ffff:ffff:ffff
131fc83:82::/32fc83:82:ffff:ffff:ffff:ffff:ffff:ffff
132fc83:83::/32fc83:83:ffff:ffff:ffff:ffff:ffff:ffff
133fc83:84::/32fc83:84:ffff:ffff:ffff:ffff:ffff:ffff
134fc83:85::/32fc83:85:ffff:ffff:ffff:ffff:ffff:ffff
135fc83:86::/32fc83:86:ffff:ffff:ffff:ffff:ffff:ffff
136fc83:87::/32fc83:87:ffff:ffff:ffff:ffff:ffff:ffff
137fc83:88::/32fc83:88:ffff:ffff:ffff:ffff:ffff:ffff
138fc83:89::/32fc83:89:ffff:ffff:ffff:ffff:ffff:ffff
139fc83:8a::/32fc83:8a:ffff:ffff:ffff:ffff:ffff:ffff
140fc83:8b::/32fc83:8b:ffff:ffff:ffff:ffff:ffff:ffff
141fc83:8c::/32fc83:8c:ffff:ffff:ffff:ffff:ffff:ffff
142fc83:8d::/32fc83:8d:ffff:ffff:ffff:ffff:ffff:ffff
143fc83:8e::/32fc83:8e:ffff:ffff:ffff:ffff:ffff:ffff
144fc83:8f::/32fc83:8f:ffff:ffff:ffff:ffff:ffff:ffff
145fc83:90::/32fc83:90:ffff:ffff:ffff:ffff:ffff:ffff
146fc83:91::/32fc83:91:ffff:ffff:ffff:ffff:ffff:ffff
147fc83:92::/32fc83:92:ffff:ffff:ffff:ffff:ffff:ffff
148fc83:93::/32fc83:93:ffff:ffff:ffff:ffff:ffff:ffff
149fc83:94::/32fc83:94:ffff:ffff:ffff:ffff:ffff:ffff
150fc83:95::/32fc83:95:ffff:ffff:ffff:ffff:ffff:ffff
151fc83:96::/32fc83:96:ffff:ffff:ffff:ffff:ffff:ffff
152fc83:97::/32fc83:97:ffff:ffff:ffff:ffff:ffff:ffff
153fc83:98::/32fc83:98:ffff:ffff:ffff:ffff:ffff:ffff
154fc83:99::/32fc83:99:ffff:ffff:ffff:ffff:ffff:ffff
155fc83:9a::/32fc83:9a:ffff:ffff:ffff:ffff:ffff:ffff
156fc83:9b::/32fc83:9b:ffff:ffff:ffff:ffff:ffff:ffff
157fc83:9c::/32fc83:9c:ffff:ffff:ffff:ffff:ffff:ffff
158fc83:9d::/32fc83:9d:ffff:ffff:ffff:ffff:ffff:ffff
159fc83:9e::/32fc83:9e:ffff:ffff:ffff:ffff:ffff:ffff
160fc83:9f::/32fc83:9f:ffff:ffff:ffff:ffff:ffff:ffff
161fc83:a0::/32fc83:a0:ffff:ffff:ffff:ffff:ffff:ffff
162fc83:a1::/32fc83:a1:ffff:ffff:ffff:ffff:ffff:ffff
163fc83:a2::/32fc83:a2:ffff:ffff:ffff:ffff:ffff:ffff
164fc83:a3::/32fc83:a3:ffff:ffff:ffff:ffff:ffff:ffff
165fc83:a4::/32fc83:a4:ffff:ffff:ffff:ffff:ffff:ffff
166fc83:a5::/32fc83:a5:ffff:ffff:ffff:ffff:ffff:ffff
167fc83:a6::/32fc83:a6:ffff:ffff:ffff:ffff:ffff:ffff
168fc83:a7::/32fc83:a7:ffff:ffff:ffff:ffff:ffff:ffff
169fc83:a8::/32fc83:a8:ffff:ffff:ffff:ffff:ffff:ffff
170fc83:a9::/32fc83:a9:ffff:ffff:ffff:ffff:ffff:ffff
171fc83:aa::/32fc83:aa:ffff:ffff:ffff:ffff:ffff:ffff
172fc83:ab::/32fc83:ab:ffff:ffff:ffff:ffff:ffff:ffff
173fc83:ac::/32fc83:ac:ffff:ffff:ffff:ffff:ffff:ffff
174fc83:ad::/32fc83:ad:ffff:ffff:ffff:ffff:ffff:ffff
175fc83:ae::/32fc83:ae:ffff:ffff:ffff:ffff:ffff:ffff
176fc83:af::/32fc83:af:ffff:ffff:ffff:ffff:ffff:ffff
177fc83:b0::/32fc83:b0:ffff:ffff:ffff:ffff:ffff:ffff
178fc83:b1::/32fc83:b1:ffff:ffff:ffff:ffff:ffff:ffff
179fc83:b2::/32fc83:b2:ffff:ffff:ffff:ffff:ffff:ffff
180fc83:b3::/32fc83:b3:ffff:ffff:ffff:ffff:ffff:ffff
181fc83:b4::/32fc83:b4:ffff:ffff:ffff:ffff:ffff:ffff
182fc83:b5::/32fc83:b5:ffff:ffff:ffff:ffff:ffff:ffff
183fc83:b6::/32fc83:b6:ffff:ffff:ffff:ffff:ffff:ffff
184fc83:b7::/32fc83:b7:ffff:ffff:ffff:ffff:ffff:ffff
185fc83:b8::/32fc83:b8:ffff:ffff:ffff:ffff:ffff:ffff
186fc83:b9::/32fc83:b9:ffff:ffff:ffff:ffff:ffff:ffff
187fc83:ba::/32fc83:ba:ffff:ffff:ffff:ffff:ffff:ffff
188fc83:bb::/32fc83:bb:ffff:ffff:ffff:ffff:ffff:ffff
189fc83:bc::/32fc83:bc:ffff:ffff:ffff:ffff:ffff:ffff
190fc83:bd::/32fc83:bd:ffff:ffff:ffff:ffff:ffff:ffff
191fc83:be::/32fc83:be:ffff:ffff:ffff:ffff:ffff:ffff
192fc83:bf::/32fc83:bf:ffff:ffff:ffff:ffff:ffff:ffff
193fc83:c0::/32fc83:c0:ffff:ffff:ffff:ffff:ffff:ffff
194fc83:c1::/32fc83:c1:ffff:ffff:ffff:ffff:ffff:ffff
195fc83:c2::/32fc83:c2:ffff:ffff:ffff:ffff:ffff:ffff
196fc83:c3::/32fc83:c3:ffff:ffff:ffff:ffff:ffff:ffff
197fc83:c4::/32fc83:c4:ffff:ffff:ffff:ffff:ffff:ffff
198fc83:c5::/32fc83:c5:ffff:ffff:ffff:ffff:ffff:ffff
199fc83:c6::/32fc83:c6:ffff:ffff:ffff:ffff:ffff:ffff
200fc83:c7::/32fc83:c7:ffff:ffff:ffff:ffff:ffff:ffff
201fc83:c8::/32fc83:c8:ffff:ffff:ffff:ffff:ffff:ffff
202fc83:c9::/32fc83:c9:ffff:ffff:ffff:ffff:ffff:ffff
203fc83:ca::/32fc83:ca:ffff:ffff:ffff:ffff:ffff:ffff
204fc83:cb::/32fc83:cb:ffff:ffff:ffff:ffff:ffff:ffff
205fc83:cc::/32fc83:cc:ffff:ffff:ffff:ffff:ffff:ffff
206fc83:cd::/32fc83:cd:ffff:ffff:ffff:ffff:ffff:ffff
207fc83:ce::/32fc83:ce:ffff:ffff:ffff:ffff:ffff:ffff
208fc83:cf::/32fc83:cf:ffff:ffff:ffff:ffff:ffff:ffff
209fc83:d0::/32fc83:d0:ffff:ffff:ffff:ffff:ffff:ffff
210fc83:d1::/32fc83:d1:ffff:ffff:ffff:ffff:ffff:ffff
211fc83:d2::/32fc83:d2:ffff:ffff:ffff:ffff:ffff:ffff
212fc83:d3::/32fc83:d3:ffff:ffff:ffff:ffff:ffff:ffff
213fc83:d4::/32fc83:d4:ffff:ffff:ffff:ffff:ffff:ffff
214fc83:d5::/32fc83:d5:ffff:ffff:ffff:ffff:ffff:ffff
215fc83:d6::/32fc83:d6:ffff:ffff:ffff:ffff:ffff:ffff
216fc83:d7::/32fc83:d7:ffff:ffff:ffff:ffff:ffff:ffff
217fc83:d8::/32fc83:d8:ffff:ffff:ffff:ffff:ffff:ffff
218fc83:d9::/32fc83:d9:ffff:ffff:ffff:ffff:ffff:ffff
219fc83:da::/32fc83:da:ffff:ffff:ffff:ffff:ffff:ffff
220fc83:db::/32fc83:db:ffff:ffff:ffff:ffff:ffff:ffff
221fc83:dc::/32fc83:dc:ffff:ffff:ffff:ffff:ffff:ffff
222fc83:dd::/32fc83:dd:ffff:ffff:ffff:ffff:ffff:ffff
223fc83:de::/32fc83:de:ffff:ffff:ffff:ffff:ffff:ffff
224fc83:df::/32fc83:df:ffff:ffff:ffff:ffff:ffff:ffff
225fc83:e0::/32fc83:e0:ffff:ffff:ffff:ffff:ffff:ffff
226fc83:e1::/32fc83:e1:ffff:ffff:ffff:ffff:ffff:ffff
227fc83:e2::/32fc83:e2:ffff:ffff:ffff:ffff:ffff:ffff
228fc83:e3::/32fc83:e3:ffff:ffff:ffff:ffff:ffff:ffff
229fc83:e4::/32fc83:e4:ffff:ffff:ffff:ffff:ffff:ffff
230fc83:e5::/32fc83:e5:ffff:ffff:ffff:ffff:ffff:ffff
231fc83:e6::/32fc83:e6:ffff:ffff:ffff:ffff:ffff:ffff
232fc83:e7::/32fc83:e7:ffff:ffff:ffff:ffff:ffff:ffff
233fc83:e8::/32fc83:e8:ffff:ffff:ffff:ffff:ffff:ffff
234fc83:e9::/32fc83:e9:ffff:ffff:ffff:ffff:ffff:ffff
235fc83:ea::/32fc83:ea:ffff:ffff:ffff:ffff:ffff:ffff
236fc83:eb::/32fc83:eb:ffff:ffff:ffff:ffff:ffff:ffff
237fc83:ec::/32fc83:ec:ffff:ffff:ffff:ffff:ffff:ffff
238fc83:ed::/32fc83:ed:ffff:ffff:ffff:ffff:ffff:ffff
239fc83:ee::/32fc83:ee:ffff:ffff:ffff:ffff:ffff:ffff
240fc83:ef::/32fc83:ef:ffff:ffff:ffff:ffff:ffff:ffff
241fc83:f0::/32fc83:f0:ffff:ffff:ffff:ffff:ffff:ffff
242fc83:f1::/32fc83:f1:ffff:ffff:ffff:ffff:ffff:ffff
243fc83:f2::/32fc83:f2:ffff:ffff:ffff:ffff:ffff:ffff
244fc83:f3::/32fc83:f3:ffff:ffff:ffff:ffff:ffff:ffff
245fc83:f4::/32fc83:f4:ffff:ffff:ffff:ffff:ffff:ffff
246fc83:f5::/32fc83:f5:ffff:ffff:ffff:ffff:ffff:ffff
247fc83:f6::/32fc83:f6:ffff:ffff:ffff:ffff:ffff:ffff
248fc83:f7::/32fc83:f7:ffff:ffff:ffff:ffff:ffff:ffff
249fc83:f8::/32fc83:f8:ffff:ffff:ffff:ffff:ffff:ffff
250fc83:f9::/32fc83:f9:ffff:ffff:ffff:ffff:ffff:ffff
251fc83:fa::/32fc83:fa:ffff:ffff:ffff:ffff:ffff:ffff
252fc83:fb::/32fc83:fb:ffff:ffff:ffff:ffff:ffff:ffff
253fc83:fc::/32fc83:fc:ffff:ffff:ffff:ffff:ffff:ffff
254fc83:fd::/32fc83:fd:ffff:ffff:ffff:ffff:ffff:ffff
255fc83:fe::/32fc83:fe:ffff:ffff:ffff:ffff:ffff:ffff
256fc83:ff::/32fc83: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.