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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
fc56::/16
First address
fc56::
Last address
fc56: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
fc56:0000:0000:0000:0000:0000:0000:0000
Type
Unique local (ULA) fc00::/7
Private IPv6, like RFC 1918; usually fd00::/8
Reverse DNS zone
6.5.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)

fc56::/16 makes 65,536 subnets of /32; the first 256 are listed.

Subnets
#SubnetLast address
1fc56::/32fc56:0:ffff:ffff:ffff:ffff:ffff:ffff
2fc56:1::/32fc56:1:ffff:ffff:ffff:ffff:ffff:ffff
3fc56:2::/32fc56:2:ffff:ffff:ffff:ffff:ffff:ffff
4fc56:3::/32fc56:3:ffff:ffff:ffff:ffff:ffff:ffff
5fc56:4::/32fc56:4:ffff:ffff:ffff:ffff:ffff:ffff
6fc56:5::/32fc56:5:ffff:ffff:ffff:ffff:ffff:ffff
7fc56:6::/32fc56:6:ffff:ffff:ffff:ffff:ffff:ffff
8fc56:7::/32fc56:7:ffff:ffff:ffff:ffff:ffff:ffff
9fc56:8::/32fc56:8:ffff:ffff:ffff:ffff:ffff:ffff
10fc56:9::/32fc56:9:ffff:ffff:ffff:ffff:ffff:ffff
11fc56:a::/32fc56:a:ffff:ffff:ffff:ffff:ffff:ffff
12fc56:b::/32fc56:b:ffff:ffff:ffff:ffff:ffff:ffff
13fc56:c::/32fc56:c:ffff:ffff:ffff:ffff:ffff:ffff
14fc56:d::/32fc56:d:ffff:ffff:ffff:ffff:ffff:ffff
15fc56:e::/32fc56:e:ffff:ffff:ffff:ffff:ffff:ffff
16fc56:f::/32fc56:f:ffff:ffff:ffff:ffff:ffff:ffff
17fc56:10::/32fc56:10:ffff:ffff:ffff:ffff:ffff:ffff
18fc56:11::/32fc56:11:ffff:ffff:ffff:ffff:ffff:ffff
19fc56:12::/32fc56:12:ffff:ffff:ffff:ffff:ffff:ffff
20fc56:13::/32fc56:13:ffff:ffff:ffff:ffff:ffff:ffff
21fc56:14::/32fc56:14:ffff:ffff:ffff:ffff:ffff:ffff
22fc56:15::/32fc56:15:ffff:ffff:ffff:ffff:ffff:ffff
23fc56:16::/32fc56:16:ffff:ffff:ffff:ffff:ffff:ffff
24fc56:17::/32fc56:17:ffff:ffff:ffff:ffff:ffff:ffff
25fc56:18::/32fc56:18:ffff:ffff:ffff:ffff:ffff:ffff
26fc56:19::/32fc56:19:ffff:ffff:ffff:ffff:ffff:ffff
27fc56:1a::/32fc56:1a:ffff:ffff:ffff:ffff:ffff:ffff
28fc56:1b::/32fc56:1b:ffff:ffff:ffff:ffff:ffff:ffff
29fc56:1c::/32fc56:1c:ffff:ffff:ffff:ffff:ffff:ffff
30fc56:1d::/32fc56:1d:ffff:ffff:ffff:ffff:ffff:ffff
31fc56:1e::/32fc56:1e:ffff:ffff:ffff:ffff:ffff:ffff
32fc56:1f::/32fc56:1f:ffff:ffff:ffff:ffff:ffff:ffff
33fc56:20::/32fc56:20:ffff:ffff:ffff:ffff:ffff:ffff
34fc56:21::/32fc56:21:ffff:ffff:ffff:ffff:ffff:ffff
35fc56:22::/32fc56:22:ffff:ffff:ffff:ffff:ffff:ffff
36fc56:23::/32fc56:23:ffff:ffff:ffff:ffff:ffff:ffff
37fc56:24::/32fc56:24:ffff:ffff:ffff:ffff:ffff:ffff
38fc56:25::/32fc56:25:ffff:ffff:ffff:ffff:ffff:ffff
39fc56:26::/32fc56:26:ffff:ffff:ffff:ffff:ffff:ffff
40fc56:27::/32fc56:27:ffff:ffff:ffff:ffff:ffff:ffff
41fc56:28::/32fc56:28:ffff:ffff:ffff:ffff:ffff:ffff
42fc56:29::/32fc56:29:ffff:ffff:ffff:ffff:ffff:ffff
43fc56:2a::/32fc56:2a:ffff:ffff:ffff:ffff:ffff:ffff
44fc56:2b::/32fc56:2b:ffff:ffff:ffff:ffff:ffff:ffff
45fc56:2c::/32fc56:2c:ffff:ffff:ffff:ffff:ffff:ffff
46fc56:2d::/32fc56:2d:ffff:ffff:ffff:ffff:ffff:ffff
47fc56:2e::/32fc56:2e:ffff:ffff:ffff:ffff:ffff:ffff
48fc56:2f::/32fc56:2f:ffff:ffff:ffff:ffff:ffff:ffff
49fc56:30::/32fc56:30:ffff:ffff:ffff:ffff:ffff:ffff
50fc56:31::/32fc56:31:ffff:ffff:ffff:ffff:ffff:ffff
51fc56:32::/32fc56:32:ffff:ffff:ffff:ffff:ffff:ffff
52fc56:33::/32fc56:33:ffff:ffff:ffff:ffff:ffff:ffff
53fc56:34::/32fc56:34:ffff:ffff:ffff:ffff:ffff:ffff
54fc56:35::/32fc56:35:ffff:ffff:ffff:ffff:ffff:ffff
55fc56:36::/32fc56:36:ffff:ffff:ffff:ffff:ffff:ffff
56fc56:37::/32fc56:37:ffff:ffff:ffff:ffff:ffff:ffff
57fc56:38::/32fc56:38:ffff:ffff:ffff:ffff:ffff:ffff
58fc56:39::/32fc56:39:ffff:ffff:ffff:ffff:ffff:ffff
59fc56:3a::/32fc56:3a:ffff:ffff:ffff:ffff:ffff:ffff
60fc56:3b::/32fc56:3b:ffff:ffff:ffff:ffff:ffff:ffff
61fc56:3c::/32fc56:3c:ffff:ffff:ffff:ffff:ffff:ffff
62fc56:3d::/32fc56:3d:ffff:ffff:ffff:ffff:ffff:ffff
63fc56:3e::/32fc56:3e:ffff:ffff:ffff:ffff:ffff:ffff
64fc56:3f::/32fc56:3f:ffff:ffff:ffff:ffff:ffff:ffff
65fc56:40::/32fc56:40:ffff:ffff:ffff:ffff:ffff:ffff
66fc56:41::/32fc56:41:ffff:ffff:ffff:ffff:ffff:ffff
67fc56:42::/32fc56:42:ffff:ffff:ffff:ffff:ffff:ffff
68fc56:43::/32fc56:43:ffff:ffff:ffff:ffff:ffff:ffff
69fc56:44::/32fc56:44:ffff:ffff:ffff:ffff:ffff:ffff
70fc56:45::/32fc56:45:ffff:ffff:ffff:ffff:ffff:ffff
71fc56:46::/32fc56:46:ffff:ffff:ffff:ffff:ffff:ffff
72fc56:47::/32fc56:47:ffff:ffff:ffff:ffff:ffff:ffff
73fc56:48::/32fc56:48:ffff:ffff:ffff:ffff:ffff:ffff
74fc56:49::/32fc56:49:ffff:ffff:ffff:ffff:ffff:ffff
75fc56:4a::/32fc56:4a:ffff:ffff:ffff:ffff:ffff:ffff
76fc56:4b::/32fc56:4b:ffff:ffff:ffff:ffff:ffff:ffff
77fc56:4c::/32fc56:4c:ffff:ffff:ffff:ffff:ffff:ffff
78fc56:4d::/32fc56:4d:ffff:ffff:ffff:ffff:ffff:ffff
79fc56:4e::/32fc56:4e:ffff:ffff:ffff:ffff:ffff:ffff
80fc56:4f::/32fc56:4f:ffff:ffff:ffff:ffff:ffff:ffff
81fc56:50::/32fc56:50:ffff:ffff:ffff:ffff:ffff:ffff
82fc56:51::/32fc56:51:ffff:ffff:ffff:ffff:ffff:ffff
83fc56:52::/32fc56:52:ffff:ffff:ffff:ffff:ffff:ffff
84fc56:53::/32fc56:53:ffff:ffff:ffff:ffff:ffff:ffff
85fc56:54::/32fc56:54:ffff:ffff:ffff:ffff:ffff:ffff
86fc56:55::/32fc56:55:ffff:ffff:ffff:ffff:ffff:ffff
87fc56:56::/32fc56:56:ffff:ffff:ffff:ffff:ffff:ffff
88fc56:57::/32fc56:57:ffff:ffff:ffff:ffff:ffff:ffff
89fc56:58::/32fc56:58:ffff:ffff:ffff:ffff:ffff:ffff
90fc56:59::/32fc56:59:ffff:ffff:ffff:ffff:ffff:ffff
91fc56:5a::/32fc56:5a:ffff:ffff:ffff:ffff:ffff:ffff
92fc56:5b::/32fc56:5b:ffff:ffff:ffff:ffff:ffff:ffff
93fc56:5c::/32fc56:5c:ffff:ffff:ffff:ffff:ffff:ffff
94fc56:5d::/32fc56:5d:ffff:ffff:ffff:ffff:ffff:ffff
95fc56:5e::/32fc56:5e:ffff:ffff:ffff:ffff:ffff:ffff
96fc56:5f::/32fc56:5f:ffff:ffff:ffff:ffff:ffff:ffff
97fc56:60::/32fc56:60:ffff:ffff:ffff:ffff:ffff:ffff
98fc56:61::/32fc56:61:ffff:ffff:ffff:ffff:ffff:ffff
99fc56:62::/32fc56:62:ffff:ffff:ffff:ffff:ffff:ffff
100fc56:63::/32fc56:63:ffff:ffff:ffff:ffff:ffff:ffff
101fc56:64::/32fc56:64:ffff:ffff:ffff:ffff:ffff:ffff
102fc56:65::/32fc56:65:ffff:ffff:ffff:ffff:ffff:ffff
103fc56:66::/32fc56:66:ffff:ffff:ffff:ffff:ffff:ffff
104fc56:67::/32fc56:67:ffff:ffff:ffff:ffff:ffff:ffff
105fc56:68::/32fc56:68:ffff:ffff:ffff:ffff:ffff:ffff
106fc56:69::/32fc56:69:ffff:ffff:ffff:ffff:ffff:ffff
107fc56:6a::/32fc56:6a:ffff:ffff:ffff:ffff:ffff:ffff
108fc56:6b::/32fc56:6b:ffff:ffff:ffff:ffff:ffff:ffff
109fc56:6c::/32fc56:6c:ffff:ffff:ffff:ffff:ffff:ffff
110fc56:6d::/32fc56:6d:ffff:ffff:ffff:ffff:ffff:ffff
111fc56:6e::/32fc56:6e:ffff:ffff:ffff:ffff:ffff:ffff
112fc56:6f::/32fc56:6f:ffff:ffff:ffff:ffff:ffff:ffff
113fc56:70::/32fc56:70:ffff:ffff:ffff:ffff:ffff:ffff
114fc56:71::/32fc56:71:ffff:ffff:ffff:ffff:ffff:ffff
115fc56:72::/32fc56:72:ffff:ffff:ffff:ffff:ffff:ffff
116fc56:73::/32fc56:73:ffff:ffff:ffff:ffff:ffff:ffff
117fc56:74::/32fc56:74:ffff:ffff:ffff:ffff:ffff:ffff
118fc56:75::/32fc56:75:ffff:ffff:ffff:ffff:ffff:ffff
119fc56:76::/32fc56:76:ffff:ffff:ffff:ffff:ffff:ffff
120fc56:77::/32fc56:77:ffff:ffff:ffff:ffff:ffff:ffff
121fc56:78::/32fc56:78:ffff:ffff:ffff:ffff:ffff:ffff
122fc56:79::/32fc56:79:ffff:ffff:ffff:ffff:ffff:ffff
123fc56:7a::/32fc56:7a:ffff:ffff:ffff:ffff:ffff:ffff
124fc56:7b::/32fc56:7b:ffff:ffff:ffff:ffff:ffff:ffff
125fc56:7c::/32fc56:7c:ffff:ffff:ffff:ffff:ffff:ffff
126fc56:7d::/32fc56:7d:ffff:ffff:ffff:ffff:ffff:ffff
127fc56:7e::/32fc56:7e:ffff:ffff:ffff:ffff:ffff:ffff
128fc56:7f::/32fc56:7f:ffff:ffff:ffff:ffff:ffff:ffff
129fc56:80::/32fc56:80:ffff:ffff:ffff:ffff:ffff:ffff
130fc56:81::/32fc56:81:ffff:ffff:ffff:ffff:ffff:ffff
131fc56:82::/32fc56:82:ffff:ffff:ffff:ffff:ffff:ffff
132fc56:83::/32fc56:83:ffff:ffff:ffff:ffff:ffff:ffff
133fc56:84::/32fc56:84:ffff:ffff:ffff:ffff:ffff:ffff
134fc56:85::/32fc56:85:ffff:ffff:ffff:ffff:ffff:ffff
135fc56:86::/32fc56:86:ffff:ffff:ffff:ffff:ffff:ffff
136fc56:87::/32fc56:87:ffff:ffff:ffff:ffff:ffff:ffff
137fc56:88::/32fc56:88:ffff:ffff:ffff:ffff:ffff:ffff
138fc56:89::/32fc56:89:ffff:ffff:ffff:ffff:ffff:ffff
139fc56:8a::/32fc56:8a:ffff:ffff:ffff:ffff:ffff:ffff
140fc56:8b::/32fc56:8b:ffff:ffff:ffff:ffff:ffff:ffff
141fc56:8c::/32fc56:8c:ffff:ffff:ffff:ffff:ffff:ffff
142fc56:8d::/32fc56:8d:ffff:ffff:ffff:ffff:ffff:ffff
143fc56:8e::/32fc56:8e:ffff:ffff:ffff:ffff:ffff:ffff
144fc56:8f::/32fc56:8f:ffff:ffff:ffff:ffff:ffff:ffff
145fc56:90::/32fc56:90:ffff:ffff:ffff:ffff:ffff:ffff
146fc56:91::/32fc56:91:ffff:ffff:ffff:ffff:ffff:ffff
147fc56:92::/32fc56:92:ffff:ffff:ffff:ffff:ffff:ffff
148fc56:93::/32fc56:93:ffff:ffff:ffff:ffff:ffff:ffff
149fc56:94::/32fc56:94:ffff:ffff:ffff:ffff:ffff:ffff
150fc56:95::/32fc56:95:ffff:ffff:ffff:ffff:ffff:ffff
151fc56:96::/32fc56:96:ffff:ffff:ffff:ffff:ffff:ffff
152fc56:97::/32fc56:97:ffff:ffff:ffff:ffff:ffff:ffff
153fc56:98::/32fc56:98:ffff:ffff:ffff:ffff:ffff:ffff
154fc56:99::/32fc56:99:ffff:ffff:ffff:ffff:ffff:ffff
155fc56:9a::/32fc56:9a:ffff:ffff:ffff:ffff:ffff:ffff
156fc56:9b::/32fc56:9b:ffff:ffff:ffff:ffff:ffff:ffff
157fc56:9c::/32fc56:9c:ffff:ffff:ffff:ffff:ffff:ffff
158fc56:9d::/32fc56:9d:ffff:ffff:ffff:ffff:ffff:ffff
159fc56:9e::/32fc56:9e:ffff:ffff:ffff:ffff:ffff:ffff
160fc56:9f::/32fc56:9f:ffff:ffff:ffff:ffff:ffff:ffff
161fc56:a0::/32fc56:a0:ffff:ffff:ffff:ffff:ffff:ffff
162fc56:a1::/32fc56:a1:ffff:ffff:ffff:ffff:ffff:ffff
163fc56:a2::/32fc56:a2:ffff:ffff:ffff:ffff:ffff:ffff
164fc56:a3::/32fc56:a3:ffff:ffff:ffff:ffff:ffff:ffff
165fc56:a4::/32fc56:a4:ffff:ffff:ffff:ffff:ffff:ffff
166fc56:a5::/32fc56:a5:ffff:ffff:ffff:ffff:ffff:ffff
167fc56:a6::/32fc56:a6:ffff:ffff:ffff:ffff:ffff:ffff
168fc56:a7::/32fc56:a7:ffff:ffff:ffff:ffff:ffff:ffff
169fc56:a8::/32fc56:a8:ffff:ffff:ffff:ffff:ffff:ffff
170fc56:a9::/32fc56:a9:ffff:ffff:ffff:ffff:ffff:ffff
171fc56:aa::/32fc56:aa:ffff:ffff:ffff:ffff:ffff:ffff
172fc56:ab::/32fc56:ab:ffff:ffff:ffff:ffff:ffff:ffff
173fc56:ac::/32fc56:ac:ffff:ffff:ffff:ffff:ffff:ffff
174fc56:ad::/32fc56:ad:ffff:ffff:ffff:ffff:ffff:ffff
175fc56:ae::/32fc56:ae:ffff:ffff:ffff:ffff:ffff:ffff
176fc56:af::/32fc56:af:ffff:ffff:ffff:ffff:ffff:ffff
177fc56:b0::/32fc56:b0:ffff:ffff:ffff:ffff:ffff:ffff
178fc56:b1::/32fc56:b1:ffff:ffff:ffff:ffff:ffff:ffff
179fc56:b2::/32fc56:b2:ffff:ffff:ffff:ffff:ffff:ffff
180fc56:b3::/32fc56:b3:ffff:ffff:ffff:ffff:ffff:ffff
181fc56:b4::/32fc56:b4:ffff:ffff:ffff:ffff:ffff:ffff
182fc56:b5::/32fc56:b5:ffff:ffff:ffff:ffff:ffff:ffff
183fc56:b6::/32fc56:b6:ffff:ffff:ffff:ffff:ffff:ffff
184fc56:b7::/32fc56:b7:ffff:ffff:ffff:ffff:ffff:ffff
185fc56:b8::/32fc56:b8:ffff:ffff:ffff:ffff:ffff:ffff
186fc56:b9::/32fc56:b9:ffff:ffff:ffff:ffff:ffff:ffff
187fc56:ba::/32fc56:ba:ffff:ffff:ffff:ffff:ffff:ffff
188fc56:bb::/32fc56:bb:ffff:ffff:ffff:ffff:ffff:ffff
189fc56:bc::/32fc56:bc:ffff:ffff:ffff:ffff:ffff:ffff
190fc56:bd::/32fc56:bd:ffff:ffff:ffff:ffff:ffff:ffff
191fc56:be::/32fc56:be:ffff:ffff:ffff:ffff:ffff:ffff
192fc56:bf::/32fc56:bf:ffff:ffff:ffff:ffff:ffff:ffff
193fc56:c0::/32fc56:c0:ffff:ffff:ffff:ffff:ffff:ffff
194fc56:c1::/32fc56:c1:ffff:ffff:ffff:ffff:ffff:ffff
195fc56:c2::/32fc56:c2:ffff:ffff:ffff:ffff:ffff:ffff
196fc56:c3::/32fc56:c3:ffff:ffff:ffff:ffff:ffff:ffff
197fc56:c4::/32fc56:c4:ffff:ffff:ffff:ffff:ffff:ffff
198fc56:c5::/32fc56:c5:ffff:ffff:ffff:ffff:ffff:ffff
199fc56:c6::/32fc56:c6:ffff:ffff:ffff:ffff:ffff:ffff
200fc56:c7::/32fc56:c7:ffff:ffff:ffff:ffff:ffff:ffff
201fc56:c8::/32fc56:c8:ffff:ffff:ffff:ffff:ffff:ffff
202fc56:c9::/32fc56:c9:ffff:ffff:ffff:ffff:ffff:ffff
203fc56:ca::/32fc56:ca:ffff:ffff:ffff:ffff:ffff:ffff
204fc56:cb::/32fc56:cb:ffff:ffff:ffff:ffff:ffff:ffff
205fc56:cc::/32fc56:cc:ffff:ffff:ffff:ffff:ffff:ffff
206fc56:cd::/32fc56:cd:ffff:ffff:ffff:ffff:ffff:ffff
207fc56:ce::/32fc56:ce:ffff:ffff:ffff:ffff:ffff:ffff
208fc56:cf::/32fc56:cf:ffff:ffff:ffff:ffff:ffff:ffff
209fc56:d0::/32fc56:d0:ffff:ffff:ffff:ffff:ffff:ffff
210fc56:d1::/32fc56:d1:ffff:ffff:ffff:ffff:ffff:ffff
211fc56:d2::/32fc56:d2:ffff:ffff:ffff:ffff:ffff:ffff
212fc56:d3::/32fc56:d3:ffff:ffff:ffff:ffff:ffff:ffff
213fc56:d4::/32fc56:d4:ffff:ffff:ffff:ffff:ffff:ffff
214fc56:d5::/32fc56:d5:ffff:ffff:ffff:ffff:ffff:ffff
215fc56:d6::/32fc56:d6:ffff:ffff:ffff:ffff:ffff:ffff
216fc56:d7::/32fc56:d7:ffff:ffff:ffff:ffff:ffff:ffff
217fc56:d8::/32fc56:d8:ffff:ffff:ffff:ffff:ffff:ffff
218fc56:d9::/32fc56:d9:ffff:ffff:ffff:ffff:ffff:ffff
219fc56:da::/32fc56:da:ffff:ffff:ffff:ffff:ffff:ffff
220fc56:db::/32fc56:db:ffff:ffff:ffff:ffff:ffff:ffff
221fc56:dc::/32fc56:dc:ffff:ffff:ffff:ffff:ffff:ffff
222fc56:dd::/32fc56:dd:ffff:ffff:ffff:ffff:ffff:ffff
223fc56:de::/32fc56:de:ffff:ffff:ffff:ffff:ffff:ffff
224fc56:df::/32fc56:df:ffff:ffff:ffff:ffff:ffff:ffff
225fc56:e0::/32fc56:e0:ffff:ffff:ffff:ffff:ffff:ffff
226fc56:e1::/32fc56:e1:ffff:ffff:ffff:ffff:ffff:ffff
227fc56:e2::/32fc56:e2:ffff:ffff:ffff:ffff:ffff:ffff
228fc56:e3::/32fc56:e3:ffff:ffff:ffff:ffff:ffff:ffff
229fc56:e4::/32fc56:e4:ffff:ffff:ffff:ffff:ffff:ffff
230fc56:e5::/32fc56:e5:ffff:ffff:ffff:ffff:ffff:ffff
231fc56:e6::/32fc56:e6:ffff:ffff:ffff:ffff:ffff:ffff
232fc56:e7::/32fc56:e7:ffff:ffff:ffff:ffff:ffff:ffff
233fc56:e8::/32fc56:e8:ffff:ffff:ffff:ffff:ffff:ffff
234fc56:e9::/32fc56:e9:ffff:ffff:ffff:ffff:ffff:ffff
235fc56:ea::/32fc56:ea:ffff:ffff:ffff:ffff:ffff:ffff
236fc56:eb::/32fc56:eb:ffff:ffff:ffff:ffff:ffff:ffff
237fc56:ec::/32fc56:ec:ffff:ffff:ffff:ffff:ffff:ffff
238fc56:ed::/32fc56:ed:ffff:ffff:ffff:ffff:ffff:ffff
239fc56:ee::/32fc56:ee:ffff:ffff:ffff:ffff:ffff:ffff
240fc56:ef::/32fc56:ef:ffff:ffff:ffff:ffff:ffff:ffff
241fc56:f0::/32fc56:f0:ffff:ffff:ffff:ffff:ffff:ffff
242fc56:f1::/32fc56:f1:ffff:ffff:ffff:ffff:ffff:ffff
243fc56:f2::/32fc56:f2:ffff:ffff:ffff:ffff:ffff:ffff
244fc56:f3::/32fc56:f3:ffff:ffff:ffff:ffff:ffff:ffff
245fc56:f4::/32fc56:f4:ffff:ffff:ffff:ffff:ffff:ffff
246fc56:f5::/32fc56:f5:ffff:ffff:ffff:ffff:ffff:ffff
247fc56:f6::/32fc56:f6:ffff:ffff:ffff:ffff:ffff:ffff
248fc56:f7::/32fc56:f7:ffff:ffff:ffff:ffff:ffff:ffff
249fc56:f8::/32fc56:f8:ffff:ffff:ffff:ffff:ffff:ffff
250fc56:f9::/32fc56:f9:ffff:ffff:ffff:ffff:ffff:ffff
251fc56:fa::/32fc56:fa:ffff:ffff:ffff:ffff:ffff:ffff
252fc56:fb::/32fc56:fb:ffff:ffff:ffff:ffff:ffff:ffff
253fc56:fc::/32fc56:fc:ffff:ffff:ffff:ffff:ffff:ffff
254fc56:fd::/32fc56:fd:ffff:ffff:ffff:ffff:ffff:ffff
255fc56:fe::/32fc56:fe:ffff:ffff:ffff:ffff:ffff:ffff
256fc56:ff::/32fc56: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.