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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
fc75::/16
First address
fc75::
Last address
fc75: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
fc75:0000:0000:0000:0000:0000:0000:0000
Type
Unique local (ULA) fc00::/7
Private IPv6, like RFC 1918; usually fd00::/8
Reverse DNS zone
5.7.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)

fc75::/16 makes 65,536 subnets of /32; the first 256 are listed.

Subnets
#SubnetLast address
1fc75::/32fc75:0:ffff:ffff:ffff:ffff:ffff:ffff
2fc75:1::/32fc75:1:ffff:ffff:ffff:ffff:ffff:ffff
3fc75:2::/32fc75:2:ffff:ffff:ffff:ffff:ffff:ffff
4fc75:3::/32fc75:3:ffff:ffff:ffff:ffff:ffff:ffff
5fc75:4::/32fc75:4:ffff:ffff:ffff:ffff:ffff:ffff
6fc75:5::/32fc75:5:ffff:ffff:ffff:ffff:ffff:ffff
7fc75:6::/32fc75:6:ffff:ffff:ffff:ffff:ffff:ffff
8fc75:7::/32fc75:7:ffff:ffff:ffff:ffff:ffff:ffff
9fc75:8::/32fc75:8:ffff:ffff:ffff:ffff:ffff:ffff
10fc75:9::/32fc75:9:ffff:ffff:ffff:ffff:ffff:ffff
11fc75:a::/32fc75:a:ffff:ffff:ffff:ffff:ffff:ffff
12fc75:b::/32fc75:b:ffff:ffff:ffff:ffff:ffff:ffff
13fc75:c::/32fc75:c:ffff:ffff:ffff:ffff:ffff:ffff
14fc75:d::/32fc75:d:ffff:ffff:ffff:ffff:ffff:ffff
15fc75:e::/32fc75:e:ffff:ffff:ffff:ffff:ffff:ffff
16fc75:f::/32fc75:f:ffff:ffff:ffff:ffff:ffff:ffff
17fc75:10::/32fc75:10:ffff:ffff:ffff:ffff:ffff:ffff
18fc75:11::/32fc75:11:ffff:ffff:ffff:ffff:ffff:ffff
19fc75:12::/32fc75:12:ffff:ffff:ffff:ffff:ffff:ffff
20fc75:13::/32fc75:13:ffff:ffff:ffff:ffff:ffff:ffff
21fc75:14::/32fc75:14:ffff:ffff:ffff:ffff:ffff:ffff
22fc75:15::/32fc75:15:ffff:ffff:ffff:ffff:ffff:ffff
23fc75:16::/32fc75:16:ffff:ffff:ffff:ffff:ffff:ffff
24fc75:17::/32fc75:17:ffff:ffff:ffff:ffff:ffff:ffff
25fc75:18::/32fc75:18:ffff:ffff:ffff:ffff:ffff:ffff
26fc75:19::/32fc75:19:ffff:ffff:ffff:ffff:ffff:ffff
27fc75:1a::/32fc75:1a:ffff:ffff:ffff:ffff:ffff:ffff
28fc75:1b::/32fc75:1b:ffff:ffff:ffff:ffff:ffff:ffff
29fc75:1c::/32fc75:1c:ffff:ffff:ffff:ffff:ffff:ffff
30fc75:1d::/32fc75:1d:ffff:ffff:ffff:ffff:ffff:ffff
31fc75:1e::/32fc75:1e:ffff:ffff:ffff:ffff:ffff:ffff
32fc75:1f::/32fc75:1f:ffff:ffff:ffff:ffff:ffff:ffff
33fc75:20::/32fc75:20:ffff:ffff:ffff:ffff:ffff:ffff
34fc75:21::/32fc75:21:ffff:ffff:ffff:ffff:ffff:ffff
35fc75:22::/32fc75:22:ffff:ffff:ffff:ffff:ffff:ffff
36fc75:23::/32fc75:23:ffff:ffff:ffff:ffff:ffff:ffff
37fc75:24::/32fc75:24:ffff:ffff:ffff:ffff:ffff:ffff
38fc75:25::/32fc75:25:ffff:ffff:ffff:ffff:ffff:ffff
39fc75:26::/32fc75:26:ffff:ffff:ffff:ffff:ffff:ffff
40fc75:27::/32fc75:27:ffff:ffff:ffff:ffff:ffff:ffff
41fc75:28::/32fc75:28:ffff:ffff:ffff:ffff:ffff:ffff
42fc75:29::/32fc75:29:ffff:ffff:ffff:ffff:ffff:ffff
43fc75:2a::/32fc75:2a:ffff:ffff:ffff:ffff:ffff:ffff
44fc75:2b::/32fc75:2b:ffff:ffff:ffff:ffff:ffff:ffff
45fc75:2c::/32fc75:2c:ffff:ffff:ffff:ffff:ffff:ffff
46fc75:2d::/32fc75:2d:ffff:ffff:ffff:ffff:ffff:ffff
47fc75:2e::/32fc75:2e:ffff:ffff:ffff:ffff:ffff:ffff
48fc75:2f::/32fc75:2f:ffff:ffff:ffff:ffff:ffff:ffff
49fc75:30::/32fc75:30:ffff:ffff:ffff:ffff:ffff:ffff
50fc75:31::/32fc75:31:ffff:ffff:ffff:ffff:ffff:ffff
51fc75:32::/32fc75:32:ffff:ffff:ffff:ffff:ffff:ffff
52fc75:33::/32fc75:33:ffff:ffff:ffff:ffff:ffff:ffff
53fc75:34::/32fc75:34:ffff:ffff:ffff:ffff:ffff:ffff
54fc75:35::/32fc75:35:ffff:ffff:ffff:ffff:ffff:ffff
55fc75:36::/32fc75:36:ffff:ffff:ffff:ffff:ffff:ffff
56fc75:37::/32fc75:37:ffff:ffff:ffff:ffff:ffff:ffff
57fc75:38::/32fc75:38:ffff:ffff:ffff:ffff:ffff:ffff
58fc75:39::/32fc75:39:ffff:ffff:ffff:ffff:ffff:ffff
59fc75:3a::/32fc75:3a:ffff:ffff:ffff:ffff:ffff:ffff
60fc75:3b::/32fc75:3b:ffff:ffff:ffff:ffff:ffff:ffff
61fc75:3c::/32fc75:3c:ffff:ffff:ffff:ffff:ffff:ffff
62fc75:3d::/32fc75:3d:ffff:ffff:ffff:ffff:ffff:ffff
63fc75:3e::/32fc75:3e:ffff:ffff:ffff:ffff:ffff:ffff
64fc75:3f::/32fc75:3f:ffff:ffff:ffff:ffff:ffff:ffff
65fc75:40::/32fc75:40:ffff:ffff:ffff:ffff:ffff:ffff
66fc75:41::/32fc75:41:ffff:ffff:ffff:ffff:ffff:ffff
67fc75:42::/32fc75:42:ffff:ffff:ffff:ffff:ffff:ffff
68fc75:43::/32fc75:43:ffff:ffff:ffff:ffff:ffff:ffff
69fc75:44::/32fc75:44:ffff:ffff:ffff:ffff:ffff:ffff
70fc75:45::/32fc75:45:ffff:ffff:ffff:ffff:ffff:ffff
71fc75:46::/32fc75:46:ffff:ffff:ffff:ffff:ffff:ffff
72fc75:47::/32fc75:47:ffff:ffff:ffff:ffff:ffff:ffff
73fc75:48::/32fc75:48:ffff:ffff:ffff:ffff:ffff:ffff
74fc75:49::/32fc75:49:ffff:ffff:ffff:ffff:ffff:ffff
75fc75:4a::/32fc75:4a:ffff:ffff:ffff:ffff:ffff:ffff
76fc75:4b::/32fc75:4b:ffff:ffff:ffff:ffff:ffff:ffff
77fc75:4c::/32fc75:4c:ffff:ffff:ffff:ffff:ffff:ffff
78fc75:4d::/32fc75:4d:ffff:ffff:ffff:ffff:ffff:ffff
79fc75:4e::/32fc75:4e:ffff:ffff:ffff:ffff:ffff:ffff
80fc75:4f::/32fc75:4f:ffff:ffff:ffff:ffff:ffff:ffff
81fc75:50::/32fc75:50:ffff:ffff:ffff:ffff:ffff:ffff
82fc75:51::/32fc75:51:ffff:ffff:ffff:ffff:ffff:ffff
83fc75:52::/32fc75:52:ffff:ffff:ffff:ffff:ffff:ffff
84fc75:53::/32fc75:53:ffff:ffff:ffff:ffff:ffff:ffff
85fc75:54::/32fc75:54:ffff:ffff:ffff:ffff:ffff:ffff
86fc75:55::/32fc75:55:ffff:ffff:ffff:ffff:ffff:ffff
87fc75:56::/32fc75:56:ffff:ffff:ffff:ffff:ffff:ffff
88fc75:57::/32fc75:57:ffff:ffff:ffff:ffff:ffff:ffff
89fc75:58::/32fc75:58:ffff:ffff:ffff:ffff:ffff:ffff
90fc75:59::/32fc75:59:ffff:ffff:ffff:ffff:ffff:ffff
91fc75:5a::/32fc75:5a:ffff:ffff:ffff:ffff:ffff:ffff
92fc75:5b::/32fc75:5b:ffff:ffff:ffff:ffff:ffff:ffff
93fc75:5c::/32fc75:5c:ffff:ffff:ffff:ffff:ffff:ffff
94fc75:5d::/32fc75:5d:ffff:ffff:ffff:ffff:ffff:ffff
95fc75:5e::/32fc75:5e:ffff:ffff:ffff:ffff:ffff:ffff
96fc75:5f::/32fc75:5f:ffff:ffff:ffff:ffff:ffff:ffff
97fc75:60::/32fc75:60:ffff:ffff:ffff:ffff:ffff:ffff
98fc75:61::/32fc75:61:ffff:ffff:ffff:ffff:ffff:ffff
99fc75:62::/32fc75:62:ffff:ffff:ffff:ffff:ffff:ffff
100fc75:63::/32fc75:63:ffff:ffff:ffff:ffff:ffff:ffff
101fc75:64::/32fc75:64:ffff:ffff:ffff:ffff:ffff:ffff
102fc75:65::/32fc75:65:ffff:ffff:ffff:ffff:ffff:ffff
103fc75:66::/32fc75:66:ffff:ffff:ffff:ffff:ffff:ffff
104fc75:67::/32fc75:67:ffff:ffff:ffff:ffff:ffff:ffff
105fc75:68::/32fc75:68:ffff:ffff:ffff:ffff:ffff:ffff
106fc75:69::/32fc75:69:ffff:ffff:ffff:ffff:ffff:ffff
107fc75:6a::/32fc75:6a:ffff:ffff:ffff:ffff:ffff:ffff
108fc75:6b::/32fc75:6b:ffff:ffff:ffff:ffff:ffff:ffff
109fc75:6c::/32fc75:6c:ffff:ffff:ffff:ffff:ffff:ffff
110fc75:6d::/32fc75:6d:ffff:ffff:ffff:ffff:ffff:ffff
111fc75:6e::/32fc75:6e:ffff:ffff:ffff:ffff:ffff:ffff
112fc75:6f::/32fc75:6f:ffff:ffff:ffff:ffff:ffff:ffff
113fc75:70::/32fc75:70:ffff:ffff:ffff:ffff:ffff:ffff
114fc75:71::/32fc75:71:ffff:ffff:ffff:ffff:ffff:ffff
115fc75:72::/32fc75:72:ffff:ffff:ffff:ffff:ffff:ffff
116fc75:73::/32fc75:73:ffff:ffff:ffff:ffff:ffff:ffff
117fc75:74::/32fc75:74:ffff:ffff:ffff:ffff:ffff:ffff
118fc75:75::/32fc75:75:ffff:ffff:ffff:ffff:ffff:ffff
119fc75:76::/32fc75:76:ffff:ffff:ffff:ffff:ffff:ffff
120fc75:77::/32fc75:77:ffff:ffff:ffff:ffff:ffff:ffff
121fc75:78::/32fc75:78:ffff:ffff:ffff:ffff:ffff:ffff
122fc75:79::/32fc75:79:ffff:ffff:ffff:ffff:ffff:ffff
123fc75:7a::/32fc75:7a:ffff:ffff:ffff:ffff:ffff:ffff
124fc75:7b::/32fc75:7b:ffff:ffff:ffff:ffff:ffff:ffff
125fc75:7c::/32fc75:7c:ffff:ffff:ffff:ffff:ffff:ffff
126fc75:7d::/32fc75:7d:ffff:ffff:ffff:ffff:ffff:ffff
127fc75:7e::/32fc75:7e:ffff:ffff:ffff:ffff:ffff:ffff
128fc75:7f::/32fc75:7f:ffff:ffff:ffff:ffff:ffff:ffff
129fc75:80::/32fc75:80:ffff:ffff:ffff:ffff:ffff:ffff
130fc75:81::/32fc75:81:ffff:ffff:ffff:ffff:ffff:ffff
131fc75:82::/32fc75:82:ffff:ffff:ffff:ffff:ffff:ffff
132fc75:83::/32fc75:83:ffff:ffff:ffff:ffff:ffff:ffff
133fc75:84::/32fc75:84:ffff:ffff:ffff:ffff:ffff:ffff
134fc75:85::/32fc75:85:ffff:ffff:ffff:ffff:ffff:ffff
135fc75:86::/32fc75:86:ffff:ffff:ffff:ffff:ffff:ffff
136fc75:87::/32fc75:87:ffff:ffff:ffff:ffff:ffff:ffff
137fc75:88::/32fc75:88:ffff:ffff:ffff:ffff:ffff:ffff
138fc75:89::/32fc75:89:ffff:ffff:ffff:ffff:ffff:ffff
139fc75:8a::/32fc75:8a:ffff:ffff:ffff:ffff:ffff:ffff
140fc75:8b::/32fc75:8b:ffff:ffff:ffff:ffff:ffff:ffff
141fc75:8c::/32fc75:8c:ffff:ffff:ffff:ffff:ffff:ffff
142fc75:8d::/32fc75:8d:ffff:ffff:ffff:ffff:ffff:ffff
143fc75:8e::/32fc75:8e:ffff:ffff:ffff:ffff:ffff:ffff
144fc75:8f::/32fc75:8f:ffff:ffff:ffff:ffff:ffff:ffff
145fc75:90::/32fc75:90:ffff:ffff:ffff:ffff:ffff:ffff
146fc75:91::/32fc75:91:ffff:ffff:ffff:ffff:ffff:ffff
147fc75:92::/32fc75:92:ffff:ffff:ffff:ffff:ffff:ffff
148fc75:93::/32fc75:93:ffff:ffff:ffff:ffff:ffff:ffff
149fc75:94::/32fc75:94:ffff:ffff:ffff:ffff:ffff:ffff
150fc75:95::/32fc75:95:ffff:ffff:ffff:ffff:ffff:ffff
151fc75:96::/32fc75:96:ffff:ffff:ffff:ffff:ffff:ffff
152fc75:97::/32fc75:97:ffff:ffff:ffff:ffff:ffff:ffff
153fc75:98::/32fc75:98:ffff:ffff:ffff:ffff:ffff:ffff
154fc75:99::/32fc75:99:ffff:ffff:ffff:ffff:ffff:ffff
155fc75:9a::/32fc75:9a:ffff:ffff:ffff:ffff:ffff:ffff
156fc75:9b::/32fc75:9b:ffff:ffff:ffff:ffff:ffff:ffff
157fc75:9c::/32fc75:9c:ffff:ffff:ffff:ffff:ffff:ffff
158fc75:9d::/32fc75:9d:ffff:ffff:ffff:ffff:ffff:ffff
159fc75:9e::/32fc75:9e:ffff:ffff:ffff:ffff:ffff:ffff
160fc75:9f::/32fc75:9f:ffff:ffff:ffff:ffff:ffff:ffff
161fc75:a0::/32fc75:a0:ffff:ffff:ffff:ffff:ffff:ffff
162fc75:a1::/32fc75:a1:ffff:ffff:ffff:ffff:ffff:ffff
163fc75:a2::/32fc75:a2:ffff:ffff:ffff:ffff:ffff:ffff
164fc75:a3::/32fc75:a3:ffff:ffff:ffff:ffff:ffff:ffff
165fc75:a4::/32fc75:a4:ffff:ffff:ffff:ffff:ffff:ffff
166fc75:a5::/32fc75:a5:ffff:ffff:ffff:ffff:ffff:ffff
167fc75:a6::/32fc75:a6:ffff:ffff:ffff:ffff:ffff:ffff
168fc75:a7::/32fc75:a7:ffff:ffff:ffff:ffff:ffff:ffff
169fc75:a8::/32fc75:a8:ffff:ffff:ffff:ffff:ffff:ffff
170fc75:a9::/32fc75:a9:ffff:ffff:ffff:ffff:ffff:ffff
171fc75:aa::/32fc75:aa:ffff:ffff:ffff:ffff:ffff:ffff
172fc75:ab::/32fc75:ab:ffff:ffff:ffff:ffff:ffff:ffff
173fc75:ac::/32fc75:ac:ffff:ffff:ffff:ffff:ffff:ffff
174fc75:ad::/32fc75:ad:ffff:ffff:ffff:ffff:ffff:ffff
175fc75:ae::/32fc75:ae:ffff:ffff:ffff:ffff:ffff:ffff
176fc75:af::/32fc75:af:ffff:ffff:ffff:ffff:ffff:ffff
177fc75:b0::/32fc75:b0:ffff:ffff:ffff:ffff:ffff:ffff
178fc75:b1::/32fc75:b1:ffff:ffff:ffff:ffff:ffff:ffff
179fc75:b2::/32fc75:b2:ffff:ffff:ffff:ffff:ffff:ffff
180fc75:b3::/32fc75:b3:ffff:ffff:ffff:ffff:ffff:ffff
181fc75:b4::/32fc75:b4:ffff:ffff:ffff:ffff:ffff:ffff
182fc75:b5::/32fc75:b5:ffff:ffff:ffff:ffff:ffff:ffff
183fc75:b6::/32fc75:b6:ffff:ffff:ffff:ffff:ffff:ffff
184fc75:b7::/32fc75:b7:ffff:ffff:ffff:ffff:ffff:ffff
185fc75:b8::/32fc75:b8:ffff:ffff:ffff:ffff:ffff:ffff
186fc75:b9::/32fc75:b9:ffff:ffff:ffff:ffff:ffff:ffff
187fc75:ba::/32fc75:ba:ffff:ffff:ffff:ffff:ffff:ffff
188fc75:bb::/32fc75:bb:ffff:ffff:ffff:ffff:ffff:ffff
189fc75:bc::/32fc75:bc:ffff:ffff:ffff:ffff:ffff:ffff
190fc75:bd::/32fc75:bd:ffff:ffff:ffff:ffff:ffff:ffff
191fc75:be::/32fc75:be:ffff:ffff:ffff:ffff:ffff:ffff
192fc75:bf::/32fc75:bf:ffff:ffff:ffff:ffff:ffff:ffff
193fc75:c0::/32fc75:c0:ffff:ffff:ffff:ffff:ffff:ffff
194fc75:c1::/32fc75:c1:ffff:ffff:ffff:ffff:ffff:ffff
195fc75:c2::/32fc75:c2:ffff:ffff:ffff:ffff:ffff:ffff
196fc75:c3::/32fc75:c3:ffff:ffff:ffff:ffff:ffff:ffff
197fc75:c4::/32fc75:c4:ffff:ffff:ffff:ffff:ffff:ffff
198fc75:c5::/32fc75:c5:ffff:ffff:ffff:ffff:ffff:ffff
199fc75:c6::/32fc75:c6:ffff:ffff:ffff:ffff:ffff:ffff
200fc75:c7::/32fc75:c7:ffff:ffff:ffff:ffff:ffff:ffff
201fc75:c8::/32fc75:c8:ffff:ffff:ffff:ffff:ffff:ffff
202fc75:c9::/32fc75:c9:ffff:ffff:ffff:ffff:ffff:ffff
203fc75:ca::/32fc75:ca:ffff:ffff:ffff:ffff:ffff:ffff
204fc75:cb::/32fc75:cb:ffff:ffff:ffff:ffff:ffff:ffff
205fc75:cc::/32fc75:cc:ffff:ffff:ffff:ffff:ffff:ffff
206fc75:cd::/32fc75:cd:ffff:ffff:ffff:ffff:ffff:ffff
207fc75:ce::/32fc75:ce:ffff:ffff:ffff:ffff:ffff:ffff
208fc75:cf::/32fc75:cf:ffff:ffff:ffff:ffff:ffff:ffff
209fc75:d0::/32fc75:d0:ffff:ffff:ffff:ffff:ffff:ffff
210fc75:d1::/32fc75:d1:ffff:ffff:ffff:ffff:ffff:ffff
211fc75:d2::/32fc75:d2:ffff:ffff:ffff:ffff:ffff:ffff
212fc75:d3::/32fc75:d3:ffff:ffff:ffff:ffff:ffff:ffff
213fc75:d4::/32fc75:d4:ffff:ffff:ffff:ffff:ffff:ffff
214fc75:d5::/32fc75:d5:ffff:ffff:ffff:ffff:ffff:ffff
215fc75:d6::/32fc75:d6:ffff:ffff:ffff:ffff:ffff:ffff
216fc75:d7::/32fc75:d7:ffff:ffff:ffff:ffff:ffff:ffff
217fc75:d8::/32fc75:d8:ffff:ffff:ffff:ffff:ffff:ffff
218fc75:d9::/32fc75:d9:ffff:ffff:ffff:ffff:ffff:ffff
219fc75:da::/32fc75:da:ffff:ffff:ffff:ffff:ffff:ffff
220fc75:db::/32fc75:db:ffff:ffff:ffff:ffff:ffff:ffff
221fc75:dc::/32fc75:dc:ffff:ffff:ffff:ffff:ffff:ffff
222fc75:dd::/32fc75:dd:ffff:ffff:ffff:ffff:ffff:ffff
223fc75:de::/32fc75:de:ffff:ffff:ffff:ffff:ffff:ffff
224fc75:df::/32fc75:df:ffff:ffff:ffff:ffff:ffff:ffff
225fc75:e0::/32fc75:e0:ffff:ffff:ffff:ffff:ffff:ffff
226fc75:e1::/32fc75:e1:ffff:ffff:ffff:ffff:ffff:ffff
227fc75:e2::/32fc75:e2:ffff:ffff:ffff:ffff:ffff:ffff
228fc75:e3::/32fc75:e3:ffff:ffff:ffff:ffff:ffff:ffff
229fc75:e4::/32fc75:e4:ffff:ffff:ffff:ffff:ffff:ffff
230fc75:e5::/32fc75:e5:ffff:ffff:ffff:ffff:ffff:ffff
231fc75:e6::/32fc75:e6:ffff:ffff:ffff:ffff:ffff:ffff
232fc75:e7::/32fc75:e7:ffff:ffff:ffff:ffff:ffff:ffff
233fc75:e8::/32fc75:e8:ffff:ffff:ffff:ffff:ffff:ffff
234fc75:e9::/32fc75:e9:ffff:ffff:ffff:ffff:ffff:ffff
235fc75:ea::/32fc75:ea:ffff:ffff:ffff:ffff:ffff:ffff
236fc75:eb::/32fc75:eb:ffff:ffff:ffff:ffff:ffff:ffff
237fc75:ec::/32fc75:ec:ffff:ffff:ffff:ffff:ffff:ffff
238fc75:ed::/32fc75:ed:ffff:ffff:ffff:ffff:ffff:ffff
239fc75:ee::/32fc75:ee:ffff:ffff:ffff:ffff:ffff:ffff
240fc75:ef::/32fc75:ef:ffff:ffff:ffff:ffff:ffff:ffff
241fc75:f0::/32fc75:f0:ffff:ffff:ffff:ffff:ffff:ffff
242fc75:f1::/32fc75:f1:ffff:ffff:ffff:ffff:ffff:ffff
243fc75:f2::/32fc75:f2:ffff:ffff:ffff:ffff:ffff:ffff
244fc75:f3::/32fc75:f3:ffff:ffff:ffff:ffff:ffff:ffff
245fc75:f4::/32fc75:f4:ffff:ffff:ffff:ffff:ffff:ffff
246fc75:f5::/32fc75:f5:ffff:ffff:ffff:ffff:ffff:ffff
247fc75:f6::/32fc75:f6:ffff:ffff:ffff:ffff:ffff:ffff
248fc75:f7::/32fc75:f7:ffff:ffff:ffff:ffff:ffff:ffff
249fc75:f8::/32fc75:f8:ffff:ffff:ffff:ffff:ffff:ffff
250fc75:f9::/32fc75:f9:ffff:ffff:ffff:ffff:ffff:ffff
251fc75:fa::/32fc75:fa:ffff:ffff:ffff:ffff:ffff:ffff
252fc75:fb::/32fc75:fb:ffff:ffff:ffff:ffff:ffff:ffff
253fc75:fc::/32fc75:fc:ffff:ffff:ffff:ffff:ffff:ffff
254fc75:fd::/32fc75:fd:ffff:ffff:ffff:ffff:ffff:ffff
255fc75:fe::/32fc75:fe:ffff:ffff:ffff:ffff:ffff:ffff
256fc75:ff::/32fc75: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.