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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
fc15::/16
First address
fc15::
Last address
fc15: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
fc15:0000:0000:0000:0000:0000:0000:0000
Type
Unique local (ULA) fc00::/7
Private IPv6, like RFC 1918; usually fd00::/8
Reverse DNS zone
5.1.c.f.ip6.arpa
Split into smaller subnets/32
/17 (2)/18 (4)/19 (8)/20 (16)/24 (256)/28 (4,096)/32 (65,536)

fc15::/16 makes 65,536 subnets of /32; the first 256 are listed.

Subnets
#SubnetLast address
1fc15::/32fc15:0:ffff:ffff:ffff:ffff:ffff:ffff
2fc15:1::/32fc15:1:ffff:ffff:ffff:ffff:ffff:ffff
3fc15:2::/32fc15:2:ffff:ffff:ffff:ffff:ffff:ffff
4fc15:3::/32fc15:3:ffff:ffff:ffff:ffff:ffff:ffff
5fc15:4::/32fc15:4:ffff:ffff:ffff:ffff:ffff:ffff
6fc15:5::/32fc15:5:ffff:ffff:ffff:ffff:ffff:ffff
7fc15:6::/32fc15:6:ffff:ffff:ffff:ffff:ffff:ffff
8fc15:7::/32fc15:7:ffff:ffff:ffff:ffff:ffff:ffff
9fc15:8::/32fc15:8:ffff:ffff:ffff:ffff:ffff:ffff
10fc15:9::/32fc15:9:ffff:ffff:ffff:ffff:ffff:ffff
11fc15:a::/32fc15:a:ffff:ffff:ffff:ffff:ffff:ffff
12fc15:b::/32fc15:b:ffff:ffff:ffff:ffff:ffff:ffff
13fc15:c::/32fc15:c:ffff:ffff:ffff:ffff:ffff:ffff
14fc15:d::/32fc15:d:ffff:ffff:ffff:ffff:ffff:ffff
15fc15:e::/32fc15:e:ffff:ffff:ffff:ffff:ffff:ffff
16fc15:f::/32fc15:f:ffff:ffff:ffff:ffff:ffff:ffff
17fc15:10::/32fc15:10:ffff:ffff:ffff:ffff:ffff:ffff
18fc15:11::/32fc15:11:ffff:ffff:ffff:ffff:ffff:ffff
19fc15:12::/32fc15:12:ffff:ffff:ffff:ffff:ffff:ffff
20fc15:13::/32fc15:13:ffff:ffff:ffff:ffff:ffff:ffff
21fc15:14::/32fc15:14:ffff:ffff:ffff:ffff:ffff:ffff
22fc15:15::/32fc15:15:ffff:ffff:ffff:ffff:ffff:ffff
23fc15:16::/32fc15:16:ffff:ffff:ffff:ffff:ffff:ffff
24fc15:17::/32fc15:17:ffff:ffff:ffff:ffff:ffff:ffff
25fc15:18::/32fc15:18:ffff:ffff:ffff:ffff:ffff:ffff
26fc15:19::/32fc15:19:ffff:ffff:ffff:ffff:ffff:ffff
27fc15:1a::/32fc15:1a:ffff:ffff:ffff:ffff:ffff:ffff
28fc15:1b::/32fc15:1b:ffff:ffff:ffff:ffff:ffff:ffff
29fc15:1c::/32fc15:1c:ffff:ffff:ffff:ffff:ffff:ffff
30fc15:1d::/32fc15:1d:ffff:ffff:ffff:ffff:ffff:ffff
31fc15:1e::/32fc15:1e:ffff:ffff:ffff:ffff:ffff:ffff
32fc15:1f::/32fc15:1f:ffff:ffff:ffff:ffff:ffff:ffff
33fc15:20::/32fc15:20:ffff:ffff:ffff:ffff:ffff:ffff
34fc15:21::/32fc15:21:ffff:ffff:ffff:ffff:ffff:ffff
35fc15:22::/32fc15:22:ffff:ffff:ffff:ffff:ffff:ffff
36fc15:23::/32fc15:23:ffff:ffff:ffff:ffff:ffff:ffff
37fc15:24::/32fc15:24:ffff:ffff:ffff:ffff:ffff:ffff
38fc15:25::/32fc15:25:ffff:ffff:ffff:ffff:ffff:ffff
39fc15:26::/32fc15:26:ffff:ffff:ffff:ffff:ffff:ffff
40fc15:27::/32fc15:27:ffff:ffff:ffff:ffff:ffff:ffff
41fc15:28::/32fc15:28:ffff:ffff:ffff:ffff:ffff:ffff
42fc15:29::/32fc15:29:ffff:ffff:ffff:ffff:ffff:ffff
43fc15:2a::/32fc15:2a:ffff:ffff:ffff:ffff:ffff:ffff
44fc15:2b::/32fc15:2b:ffff:ffff:ffff:ffff:ffff:ffff
45fc15:2c::/32fc15:2c:ffff:ffff:ffff:ffff:ffff:ffff
46fc15:2d::/32fc15:2d:ffff:ffff:ffff:ffff:ffff:ffff
47fc15:2e::/32fc15:2e:ffff:ffff:ffff:ffff:ffff:ffff
48fc15:2f::/32fc15:2f:ffff:ffff:ffff:ffff:ffff:ffff
49fc15:30::/32fc15:30:ffff:ffff:ffff:ffff:ffff:ffff
50fc15:31::/32fc15:31:ffff:ffff:ffff:ffff:ffff:ffff
51fc15:32::/32fc15:32:ffff:ffff:ffff:ffff:ffff:ffff
52fc15:33::/32fc15:33:ffff:ffff:ffff:ffff:ffff:ffff
53fc15:34::/32fc15:34:ffff:ffff:ffff:ffff:ffff:ffff
54fc15:35::/32fc15:35:ffff:ffff:ffff:ffff:ffff:ffff
55fc15:36::/32fc15:36:ffff:ffff:ffff:ffff:ffff:ffff
56fc15:37::/32fc15:37:ffff:ffff:ffff:ffff:ffff:ffff
57fc15:38::/32fc15:38:ffff:ffff:ffff:ffff:ffff:ffff
58fc15:39::/32fc15:39:ffff:ffff:ffff:ffff:ffff:ffff
59fc15:3a::/32fc15:3a:ffff:ffff:ffff:ffff:ffff:ffff
60fc15:3b::/32fc15:3b:ffff:ffff:ffff:ffff:ffff:ffff
61fc15:3c::/32fc15:3c:ffff:ffff:ffff:ffff:ffff:ffff
62fc15:3d::/32fc15:3d:ffff:ffff:ffff:ffff:ffff:ffff
63fc15:3e::/32fc15:3e:ffff:ffff:ffff:ffff:ffff:ffff
64fc15:3f::/32fc15:3f:ffff:ffff:ffff:ffff:ffff:ffff
65fc15:40::/32fc15:40:ffff:ffff:ffff:ffff:ffff:ffff
66fc15:41::/32fc15:41:ffff:ffff:ffff:ffff:ffff:ffff
67fc15:42::/32fc15:42:ffff:ffff:ffff:ffff:ffff:ffff
68fc15:43::/32fc15:43:ffff:ffff:ffff:ffff:ffff:ffff
69fc15:44::/32fc15:44:ffff:ffff:ffff:ffff:ffff:ffff
70fc15:45::/32fc15:45:ffff:ffff:ffff:ffff:ffff:ffff
71fc15:46::/32fc15:46:ffff:ffff:ffff:ffff:ffff:ffff
72fc15:47::/32fc15:47:ffff:ffff:ffff:ffff:ffff:ffff
73fc15:48::/32fc15:48:ffff:ffff:ffff:ffff:ffff:ffff
74fc15:49::/32fc15:49:ffff:ffff:ffff:ffff:ffff:ffff
75fc15:4a::/32fc15:4a:ffff:ffff:ffff:ffff:ffff:ffff
76fc15:4b::/32fc15:4b:ffff:ffff:ffff:ffff:ffff:ffff
77fc15:4c::/32fc15:4c:ffff:ffff:ffff:ffff:ffff:ffff
78fc15:4d::/32fc15:4d:ffff:ffff:ffff:ffff:ffff:ffff
79fc15:4e::/32fc15:4e:ffff:ffff:ffff:ffff:ffff:ffff
80fc15:4f::/32fc15:4f:ffff:ffff:ffff:ffff:ffff:ffff
81fc15:50::/32fc15:50:ffff:ffff:ffff:ffff:ffff:ffff
82fc15:51::/32fc15:51:ffff:ffff:ffff:ffff:ffff:ffff
83fc15:52::/32fc15:52:ffff:ffff:ffff:ffff:ffff:ffff
84fc15:53::/32fc15:53:ffff:ffff:ffff:ffff:ffff:ffff
85fc15:54::/32fc15:54:ffff:ffff:ffff:ffff:ffff:ffff
86fc15:55::/32fc15:55:ffff:ffff:ffff:ffff:ffff:ffff
87fc15:56::/32fc15:56:ffff:ffff:ffff:ffff:ffff:ffff
88fc15:57::/32fc15:57:ffff:ffff:ffff:ffff:ffff:ffff
89fc15:58::/32fc15:58:ffff:ffff:ffff:ffff:ffff:ffff
90fc15:59::/32fc15:59:ffff:ffff:ffff:ffff:ffff:ffff
91fc15:5a::/32fc15:5a:ffff:ffff:ffff:ffff:ffff:ffff
92fc15:5b::/32fc15:5b:ffff:ffff:ffff:ffff:ffff:ffff
93fc15:5c::/32fc15:5c:ffff:ffff:ffff:ffff:ffff:ffff
94fc15:5d::/32fc15:5d:ffff:ffff:ffff:ffff:ffff:ffff
95fc15:5e::/32fc15:5e:ffff:ffff:ffff:ffff:ffff:ffff
96fc15:5f::/32fc15:5f:ffff:ffff:ffff:ffff:ffff:ffff
97fc15:60::/32fc15:60:ffff:ffff:ffff:ffff:ffff:ffff
98fc15:61::/32fc15:61:ffff:ffff:ffff:ffff:ffff:ffff
99fc15:62::/32fc15:62:ffff:ffff:ffff:ffff:ffff:ffff
100fc15:63::/32fc15:63:ffff:ffff:ffff:ffff:ffff:ffff
101fc15:64::/32fc15:64:ffff:ffff:ffff:ffff:ffff:ffff
102fc15:65::/32fc15:65:ffff:ffff:ffff:ffff:ffff:ffff
103fc15:66::/32fc15:66:ffff:ffff:ffff:ffff:ffff:ffff
104fc15:67::/32fc15:67:ffff:ffff:ffff:ffff:ffff:ffff
105fc15:68::/32fc15:68:ffff:ffff:ffff:ffff:ffff:ffff
106fc15:69::/32fc15:69:ffff:ffff:ffff:ffff:ffff:ffff
107fc15:6a::/32fc15:6a:ffff:ffff:ffff:ffff:ffff:ffff
108fc15:6b::/32fc15:6b:ffff:ffff:ffff:ffff:ffff:ffff
109fc15:6c::/32fc15:6c:ffff:ffff:ffff:ffff:ffff:ffff
110fc15:6d::/32fc15:6d:ffff:ffff:ffff:ffff:ffff:ffff
111fc15:6e::/32fc15:6e:ffff:ffff:ffff:ffff:ffff:ffff
112fc15:6f::/32fc15:6f:ffff:ffff:ffff:ffff:ffff:ffff
113fc15:70::/32fc15:70:ffff:ffff:ffff:ffff:ffff:ffff
114fc15:71::/32fc15:71:ffff:ffff:ffff:ffff:ffff:ffff
115fc15:72::/32fc15:72:ffff:ffff:ffff:ffff:ffff:ffff
116fc15:73::/32fc15:73:ffff:ffff:ffff:ffff:ffff:ffff
117fc15:74::/32fc15:74:ffff:ffff:ffff:ffff:ffff:ffff
118fc15:75::/32fc15:75:ffff:ffff:ffff:ffff:ffff:ffff
119fc15:76::/32fc15:76:ffff:ffff:ffff:ffff:ffff:ffff
120fc15:77::/32fc15:77:ffff:ffff:ffff:ffff:ffff:ffff
121fc15:78::/32fc15:78:ffff:ffff:ffff:ffff:ffff:ffff
122fc15:79::/32fc15:79:ffff:ffff:ffff:ffff:ffff:ffff
123fc15:7a::/32fc15:7a:ffff:ffff:ffff:ffff:ffff:ffff
124fc15:7b::/32fc15:7b:ffff:ffff:ffff:ffff:ffff:ffff
125fc15:7c::/32fc15:7c:ffff:ffff:ffff:ffff:ffff:ffff
126fc15:7d::/32fc15:7d:ffff:ffff:ffff:ffff:ffff:ffff
127fc15:7e::/32fc15:7e:ffff:ffff:ffff:ffff:ffff:ffff
128fc15:7f::/32fc15:7f:ffff:ffff:ffff:ffff:ffff:ffff
129fc15:80::/32fc15:80:ffff:ffff:ffff:ffff:ffff:ffff
130fc15:81::/32fc15:81:ffff:ffff:ffff:ffff:ffff:ffff
131fc15:82::/32fc15:82:ffff:ffff:ffff:ffff:ffff:ffff
132fc15:83::/32fc15:83:ffff:ffff:ffff:ffff:ffff:ffff
133fc15:84::/32fc15:84:ffff:ffff:ffff:ffff:ffff:ffff
134fc15:85::/32fc15:85:ffff:ffff:ffff:ffff:ffff:ffff
135fc15:86::/32fc15:86:ffff:ffff:ffff:ffff:ffff:ffff
136fc15:87::/32fc15:87:ffff:ffff:ffff:ffff:ffff:ffff
137fc15:88::/32fc15:88:ffff:ffff:ffff:ffff:ffff:ffff
138fc15:89::/32fc15:89:ffff:ffff:ffff:ffff:ffff:ffff
139fc15:8a::/32fc15:8a:ffff:ffff:ffff:ffff:ffff:ffff
140fc15:8b::/32fc15:8b:ffff:ffff:ffff:ffff:ffff:ffff
141fc15:8c::/32fc15:8c:ffff:ffff:ffff:ffff:ffff:ffff
142fc15:8d::/32fc15:8d:ffff:ffff:ffff:ffff:ffff:ffff
143fc15:8e::/32fc15:8e:ffff:ffff:ffff:ffff:ffff:ffff
144fc15:8f::/32fc15:8f:ffff:ffff:ffff:ffff:ffff:ffff
145fc15:90::/32fc15:90:ffff:ffff:ffff:ffff:ffff:ffff
146fc15:91::/32fc15:91:ffff:ffff:ffff:ffff:ffff:ffff
147fc15:92::/32fc15:92:ffff:ffff:ffff:ffff:ffff:ffff
148fc15:93::/32fc15:93:ffff:ffff:ffff:ffff:ffff:ffff
149fc15:94::/32fc15:94:ffff:ffff:ffff:ffff:ffff:ffff
150fc15:95::/32fc15:95:ffff:ffff:ffff:ffff:ffff:ffff
151fc15:96::/32fc15:96:ffff:ffff:ffff:ffff:ffff:ffff
152fc15:97::/32fc15:97:ffff:ffff:ffff:ffff:ffff:ffff
153fc15:98::/32fc15:98:ffff:ffff:ffff:ffff:ffff:ffff
154fc15:99::/32fc15:99:ffff:ffff:ffff:ffff:ffff:ffff
155fc15:9a::/32fc15:9a:ffff:ffff:ffff:ffff:ffff:ffff
156fc15:9b::/32fc15:9b:ffff:ffff:ffff:ffff:ffff:ffff
157fc15:9c::/32fc15:9c:ffff:ffff:ffff:ffff:ffff:ffff
158fc15:9d::/32fc15:9d:ffff:ffff:ffff:ffff:ffff:ffff
159fc15:9e::/32fc15:9e:ffff:ffff:ffff:ffff:ffff:ffff
160fc15:9f::/32fc15:9f:ffff:ffff:ffff:ffff:ffff:ffff
161fc15:a0::/32fc15:a0:ffff:ffff:ffff:ffff:ffff:ffff
162fc15:a1::/32fc15:a1:ffff:ffff:ffff:ffff:ffff:ffff
163fc15:a2::/32fc15:a2:ffff:ffff:ffff:ffff:ffff:ffff
164fc15:a3::/32fc15:a3:ffff:ffff:ffff:ffff:ffff:ffff
165fc15:a4::/32fc15:a4:ffff:ffff:ffff:ffff:ffff:ffff
166fc15:a5::/32fc15:a5:ffff:ffff:ffff:ffff:ffff:ffff
167fc15:a6::/32fc15:a6:ffff:ffff:ffff:ffff:ffff:ffff
168fc15:a7::/32fc15:a7:ffff:ffff:ffff:ffff:ffff:ffff
169fc15:a8::/32fc15:a8:ffff:ffff:ffff:ffff:ffff:ffff
170fc15:a9::/32fc15:a9:ffff:ffff:ffff:ffff:ffff:ffff
171fc15:aa::/32fc15:aa:ffff:ffff:ffff:ffff:ffff:ffff
172fc15:ab::/32fc15:ab:ffff:ffff:ffff:ffff:ffff:ffff
173fc15:ac::/32fc15:ac:ffff:ffff:ffff:ffff:ffff:ffff
174fc15:ad::/32fc15:ad:ffff:ffff:ffff:ffff:ffff:ffff
175fc15:ae::/32fc15:ae:ffff:ffff:ffff:ffff:ffff:ffff
176fc15:af::/32fc15:af:ffff:ffff:ffff:ffff:ffff:ffff
177fc15:b0::/32fc15:b0:ffff:ffff:ffff:ffff:ffff:ffff
178fc15:b1::/32fc15:b1:ffff:ffff:ffff:ffff:ffff:ffff
179fc15:b2::/32fc15:b2:ffff:ffff:ffff:ffff:ffff:ffff
180fc15:b3::/32fc15:b3:ffff:ffff:ffff:ffff:ffff:ffff
181fc15:b4::/32fc15:b4:ffff:ffff:ffff:ffff:ffff:ffff
182fc15:b5::/32fc15:b5:ffff:ffff:ffff:ffff:ffff:ffff
183fc15:b6::/32fc15:b6:ffff:ffff:ffff:ffff:ffff:ffff
184fc15:b7::/32fc15:b7:ffff:ffff:ffff:ffff:ffff:ffff
185fc15:b8::/32fc15:b8:ffff:ffff:ffff:ffff:ffff:ffff
186fc15:b9::/32fc15:b9:ffff:ffff:ffff:ffff:ffff:ffff
187fc15:ba::/32fc15:ba:ffff:ffff:ffff:ffff:ffff:ffff
188fc15:bb::/32fc15:bb:ffff:ffff:ffff:ffff:ffff:ffff
189fc15:bc::/32fc15:bc:ffff:ffff:ffff:ffff:ffff:ffff
190fc15:bd::/32fc15:bd:ffff:ffff:ffff:ffff:ffff:ffff
191fc15:be::/32fc15:be:ffff:ffff:ffff:ffff:ffff:ffff
192fc15:bf::/32fc15:bf:ffff:ffff:ffff:ffff:ffff:ffff
193fc15:c0::/32fc15:c0:ffff:ffff:ffff:ffff:ffff:ffff
194fc15:c1::/32fc15:c1:ffff:ffff:ffff:ffff:ffff:ffff
195fc15:c2::/32fc15:c2:ffff:ffff:ffff:ffff:ffff:ffff
196fc15:c3::/32fc15:c3:ffff:ffff:ffff:ffff:ffff:ffff
197fc15:c4::/32fc15:c4:ffff:ffff:ffff:ffff:ffff:ffff
198fc15:c5::/32fc15:c5:ffff:ffff:ffff:ffff:ffff:ffff
199fc15:c6::/32fc15:c6:ffff:ffff:ffff:ffff:ffff:ffff
200fc15:c7::/32fc15:c7:ffff:ffff:ffff:ffff:ffff:ffff
201fc15:c8::/32fc15:c8:ffff:ffff:ffff:ffff:ffff:ffff
202fc15:c9::/32fc15:c9:ffff:ffff:ffff:ffff:ffff:ffff
203fc15:ca::/32fc15:ca:ffff:ffff:ffff:ffff:ffff:ffff
204fc15:cb::/32fc15:cb:ffff:ffff:ffff:ffff:ffff:ffff
205fc15:cc::/32fc15:cc:ffff:ffff:ffff:ffff:ffff:ffff
206fc15:cd::/32fc15:cd:ffff:ffff:ffff:ffff:ffff:ffff
207fc15:ce::/32fc15:ce:ffff:ffff:ffff:ffff:ffff:ffff
208fc15:cf::/32fc15:cf:ffff:ffff:ffff:ffff:ffff:ffff
209fc15:d0::/32fc15:d0:ffff:ffff:ffff:ffff:ffff:ffff
210fc15:d1::/32fc15:d1:ffff:ffff:ffff:ffff:ffff:ffff
211fc15:d2::/32fc15:d2:ffff:ffff:ffff:ffff:ffff:ffff
212fc15:d3::/32fc15:d3:ffff:ffff:ffff:ffff:ffff:ffff
213fc15:d4::/32fc15:d4:ffff:ffff:ffff:ffff:ffff:ffff
214fc15:d5::/32fc15:d5:ffff:ffff:ffff:ffff:ffff:ffff
215fc15:d6::/32fc15:d6:ffff:ffff:ffff:ffff:ffff:ffff
216fc15:d7::/32fc15:d7:ffff:ffff:ffff:ffff:ffff:ffff
217fc15:d8::/32fc15:d8:ffff:ffff:ffff:ffff:ffff:ffff
218fc15:d9::/32fc15:d9:ffff:ffff:ffff:ffff:ffff:ffff
219fc15:da::/32fc15:da:ffff:ffff:ffff:ffff:ffff:ffff
220fc15:db::/32fc15:db:ffff:ffff:ffff:ffff:ffff:ffff
221fc15:dc::/32fc15:dc:ffff:ffff:ffff:ffff:ffff:ffff
222fc15:dd::/32fc15:dd:ffff:ffff:ffff:ffff:ffff:ffff
223fc15:de::/32fc15:de:ffff:ffff:ffff:ffff:ffff:ffff
224fc15:df::/32fc15:df:ffff:ffff:ffff:ffff:ffff:ffff
225fc15:e0::/32fc15:e0:ffff:ffff:ffff:ffff:ffff:ffff
226fc15:e1::/32fc15:e1:ffff:ffff:ffff:ffff:ffff:ffff
227fc15:e2::/32fc15:e2:ffff:ffff:ffff:ffff:ffff:ffff
228fc15:e3::/32fc15:e3:ffff:ffff:ffff:ffff:ffff:ffff
229fc15:e4::/32fc15:e4:ffff:ffff:ffff:ffff:ffff:ffff
230fc15:e5::/32fc15:e5:ffff:ffff:ffff:ffff:ffff:ffff
231fc15:e6::/32fc15:e6:ffff:ffff:ffff:ffff:ffff:ffff
232fc15:e7::/32fc15:e7:ffff:ffff:ffff:ffff:ffff:ffff
233fc15:e8::/32fc15:e8:ffff:ffff:ffff:ffff:ffff:ffff
234fc15:e9::/32fc15:e9:ffff:ffff:ffff:ffff:ffff:ffff
235fc15:ea::/32fc15:ea:ffff:ffff:ffff:ffff:ffff:ffff
236fc15:eb::/32fc15:eb:ffff:ffff:ffff:ffff:ffff:ffff
237fc15:ec::/32fc15:ec:ffff:ffff:ffff:ffff:ffff:ffff
238fc15:ed::/32fc15:ed:ffff:ffff:ffff:ffff:ffff:ffff
239fc15:ee::/32fc15:ee:ffff:ffff:ffff:ffff:ffff:ffff
240fc15:ef::/32fc15:ef:ffff:ffff:ffff:ffff:ffff:ffff
241fc15:f0::/32fc15:f0:ffff:ffff:ffff:ffff:ffff:ffff
242fc15:f1::/32fc15:f1:ffff:ffff:ffff:ffff:ffff:ffff
243fc15:f2::/32fc15:f2:ffff:ffff:ffff:ffff:ffff:ffff
244fc15:f3::/32fc15:f3:ffff:ffff:ffff:ffff:ffff:ffff
245fc15:f4::/32fc15:f4:ffff:ffff:ffff:ffff:ffff:ffff
246fc15:f5::/32fc15:f5:ffff:ffff:ffff:ffff:ffff:ffff
247fc15:f6::/32fc15:f6:ffff:ffff:ffff:ffff:ffff:ffff
248fc15:f7::/32fc15:f7:ffff:ffff:ffff:ffff:ffff:ffff
249fc15:f8::/32fc15:f8:ffff:ffff:ffff:ffff:ffff:ffff
250fc15:f9::/32fc15:f9:ffff:ffff:ffff:ffff:ffff:ffff
251fc15:fa::/32fc15:fa:ffff:ffff:ffff:ffff:ffff:ffff
252fc15:fb::/32fc15:fb:ffff:ffff:ffff:ffff:ffff:ffff
253fc15:fc::/32fc15:fc:ffff:ffff:ffff:ffff:ffff:ffff
254fc15:fd::/32fc15:fd:ffff:ffff:ffff:ffff:ffff:ffff
255fc15:fe::/32fc15:fe:ffff:ffff:ffff:ffff:ffff:ffff
256fc15:ff::/32fc15: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.