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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
fc2b::/16
First address
fc2b::
Last address
fc2b: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
fc2b:0000:0000:0000:0000:0000:0000:0000
Type
Unique local (ULA) fc00::/7
Private IPv6, like RFC 1918; usually fd00::/8
Reverse DNS zone
b.2.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)

fc2b::/16 makes 65,536 subnets of /32; the first 256 are listed.

Subnets
#SubnetLast address
1fc2b::/32fc2b:0:ffff:ffff:ffff:ffff:ffff:ffff
2fc2b:1::/32fc2b:1:ffff:ffff:ffff:ffff:ffff:ffff
3fc2b:2::/32fc2b:2:ffff:ffff:ffff:ffff:ffff:ffff
4fc2b:3::/32fc2b:3:ffff:ffff:ffff:ffff:ffff:ffff
5fc2b:4::/32fc2b:4:ffff:ffff:ffff:ffff:ffff:ffff
6fc2b:5::/32fc2b:5:ffff:ffff:ffff:ffff:ffff:ffff
7fc2b:6::/32fc2b:6:ffff:ffff:ffff:ffff:ffff:ffff
8fc2b:7::/32fc2b:7:ffff:ffff:ffff:ffff:ffff:ffff
9fc2b:8::/32fc2b:8:ffff:ffff:ffff:ffff:ffff:ffff
10fc2b:9::/32fc2b:9:ffff:ffff:ffff:ffff:ffff:ffff
11fc2b:a::/32fc2b:a:ffff:ffff:ffff:ffff:ffff:ffff
12fc2b:b::/32fc2b:b:ffff:ffff:ffff:ffff:ffff:ffff
13fc2b:c::/32fc2b:c:ffff:ffff:ffff:ffff:ffff:ffff
14fc2b:d::/32fc2b:d:ffff:ffff:ffff:ffff:ffff:ffff
15fc2b:e::/32fc2b:e:ffff:ffff:ffff:ffff:ffff:ffff
16fc2b:f::/32fc2b:f:ffff:ffff:ffff:ffff:ffff:ffff
17fc2b:10::/32fc2b:10:ffff:ffff:ffff:ffff:ffff:ffff
18fc2b:11::/32fc2b:11:ffff:ffff:ffff:ffff:ffff:ffff
19fc2b:12::/32fc2b:12:ffff:ffff:ffff:ffff:ffff:ffff
20fc2b:13::/32fc2b:13:ffff:ffff:ffff:ffff:ffff:ffff
21fc2b:14::/32fc2b:14:ffff:ffff:ffff:ffff:ffff:ffff
22fc2b:15::/32fc2b:15:ffff:ffff:ffff:ffff:ffff:ffff
23fc2b:16::/32fc2b:16:ffff:ffff:ffff:ffff:ffff:ffff
24fc2b:17::/32fc2b:17:ffff:ffff:ffff:ffff:ffff:ffff
25fc2b:18::/32fc2b:18:ffff:ffff:ffff:ffff:ffff:ffff
26fc2b:19::/32fc2b:19:ffff:ffff:ffff:ffff:ffff:ffff
27fc2b:1a::/32fc2b:1a:ffff:ffff:ffff:ffff:ffff:ffff
28fc2b:1b::/32fc2b:1b:ffff:ffff:ffff:ffff:ffff:ffff
29fc2b:1c::/32fc2b:1c:ffff:ffff:ffff:ffff:ffff:ffff
30fc2b:1d::/32fc2b:1d:ffff:ffff:ffff:ffff:ffff:ffff
31fc2b:1e::/32fc2b:1e:ffff:ffff:ffff:ffff:ffff:ffff
32fc2b:1f::/32fc2b:1f:ffff:ffff:ffff:ffff:ffff:ffff
33fc2b:20::/32fc2b:20:ffff:ffff:ffff:ffff:ffff:ffff
34fc2b:21::/32fc2b:21:ffff:ffff:ffff:ffff:ffff:ffff
35fc2b:22::/32fc2b:22:ffff:ffff:ffff:ffff:ffff:ffff
36fc2b:23::/32fc2b:23:ffff:ffff:ffff:ffff:ffff:ffff
37fc2b:24::/32fc2b:24:ffff:ffff:ffff:ffff:ffff:ffff
38fc2b:25::/32fc2b:25:ffff:ffff:ffff:ffff:ffff:ffff
39fc2b:26::/32fc2b:26:ffff:ffff:ffff:ffff:ffff:ffff
40fc2b:27::/32fc2b:27:ffff:ffff:ffff:ffff:ffff:ffff
41fc2b:28::/32fc2b:28:ffff:ffff:ffff:ffff:ffff:ffff
42fc2b:29::/32fc2b:29:ffff:ffff:ffff:ffff:ffff:ffff
43fc2b:2a::/32fc2b:2a:ffff:ffff:ffff:ffff:ffff:ffff
44fc2b:2b::/32fc2b:2b:ffff:ffff:ffff:ffff:ffff:ffff
45fc2b:2c::/32fc2b:2c:ffff:ffff:ffff:ffff:ffff:ffff
46fc2b:2d::/32fc2b:2d:ffff:ffff:ffff:ffff:ffff:ffff
47fc2b:2e::/32fc2b:2e:ffff:ffff:ffff:ffff:ffff:ffff
48fc2b:2f::/32fc2b:2f:ffff:ffff:ffff:ffff:ffff:ffff
49fc2b:30::/32fc2b:30:ffff:ffff:ffff:ffff:ffff:ffff
50fc2b:31::/32fc2b:31:ffff:ffff:ffff:ffff:ffff:ffff
51fc2b:32::/32fc2b:32:ffff:ffff:ffff:ffff:ffff:ffff
52fc2b:33::/32fc2b:33:ffff:ffff:ffff:ffff:ffff:ffff
53fc2b:34::/32fc2b:34:ffff:ffff:ffff:ffff:ffff:ffff
54fc2b:35::/32fc2b:35:ffff:ffff:ffff:ffff:ffff:ffff
55fc2b:36::/32fc2b:36:ffff:ffff:ffff:ffff:ffff:ffff
56fc2b:37::/32fc2b:37:ffff:ffff:ffff:ffff:ffff:ffff
57fc2b:38::/32fc2b:38:ffff:ffff:ffff:ffff:ffff:ffff
58fc2b:39::/32fc2b:39:ffff:ffff:ffff:ffff:ffff:ffff
59fc2b:3a::/32fc2b:3a:ffff:ffff:ffff:ffff:ffff:ffff
60fc2b:3b::/32fc2b:3b:ffff:ffff:ffff:ffff:ffff:ffff
61fc2b:3c::/32fc2b:3c:ffff:ffff:ffff:ffff:ffff:ffff
62fc2b:3d::/32fc2b:3d:ffff:ffff:ffff:ffff:ffff:ffff
63fc2b:3e::/32fc2b:3e:ffff:ffff:ffff:ffff:ffff:ffff
64fc2b:3f::/32fc2b:3f:ffff:ffff:ffff:ffff:ffff:ffff
65fc2b:40::/32fc2b:40:ffff:ffff:ffff:ffff:ffff:ffff
66fc2b:41::/32fc2b:41:ffff:ffff:ffff:ffff:ffff:ffff
67fc2b:42::/32fc2b:42:ffff:ffff:ffff:ffff:ffff:ffff
68fc2b:43::/32fc2b:43:ffff:ffff:ffff:ffff:ffff:ffff
69fc2b:44::/32fc2b:44:ffff:ffff:ffff:ffff:ffff:ffff
70fc2b:45::/32fc2b:45:ffff:ffff:ffff:ffff:ffff:ffff
71fc2b:46::/32fc2b:46:ffff:ffff:ffff:ffff:ffff:ffff
72fc2b:47::/32fc2b:47:ffff:ffff:ffff:ffff:ffff:ffff
73fc2b:48::/32fc2b:48:ffff:ffff:ffff:ffff:ffff:ffff
74fc2b:49::/32fc2b:49:ffff:ffff:ffff:ffff:ffff:ffff
75fc2b:4a::/32fc2b:4a:ffff:ffff:ffff:ffff:ffff:ffff
76fc2b:4b::/32fc2b:4b:ffff:ffff:ffff:ffff:ffff:ffff
77fc2b:4c::/32fc2b:4c:ffff:ffff:ffff:ffff:ffff:ffff
78fc2b:4d::/32fc2b:4d:ffff:ffff:ffff:ffff:ffff:ffff
79fc2b:4e::/32fc2b:4e:ffff:ffff:ffff:ffff:ffff:ffff
80fc2b:4f::/32fc2b:4f:ffff:ffff:ffff:ffff:ffff:ffff
81fc2b:50::/32fc2b:50:ffff:ffff:ffff:ffff:ffff:ffff
82fc2b:51::/32fc2b:51:ffff:ffff:ffff:ffff:ffff:ffff
83fc2b:52::/32fc2b:52:ffff:ffff:ffff:ffff:ffff:ffff
84fc2b:53::/32fc2b:53:ffff:ffff:ffff:ffff:ffff:ffff
85fc2b:54::/32fc2b:54:ffff:ffff:ffff:ffff:ffff:ffff
86fc2b:55::/32fc2b:55:ffff:ffff:ffff:ffff:ffff:ffff
87fc2b:56::/32fc2b:56:ffff:ffff:ffff:ffff:ffff:ffff
88fc2b:57::/32fc2b:57:ffff:ffff:ffff:ffff:ffff:ffff
89fc2b:58::/32fc2b:58:ffff:ffff:ffff:ffff:ffff:ffff
90fc2b:59::/32fc2b:59:ffff:ffff:ffff:ffff:ffff:ffff
91fc2b:5a::/32fc2b:5a:ffff:ffff:ffff:ffff:ffff:ffff
92fc2b:5b::/32fc2b:5b:ffff:ffff:ffff:ffff:ffff:ffff
93fc2b:5c::/32fc2b:5c:ffff:ffff:ffff:ffff:ffff:ffff
94fc2b:5d::/32fc2b:5d:ffff:ffff:ffff:ffff:ffff:ffff
95fc2b:5e::/32fc2b:5e:ffff:ffff:ffff:ffff:ffff:ffff
96fc2b:5f::/32fc2b:5f:ffff:ffff:ffff:ffff:ffff:ffff
97fc2b:60::/32fc2b:60:ffff:ffff:ffff:ffff:ffff:ffff
98fc2b:61::/32fc2b:61:ffff:ffff:ffff:ffff:ffff:ffff
99fc2b:62::/32fc2b:62:ffff:ffff:ffff:ffff:ffff:ffff
100fc2b:63::/32fc2b:63:ffff:ffff:ffff:ffff:ffff:ffff
101fc2b:64::/32fc2b:64:ffff:ffff:ffff:ffff:ffff:ffff
102fc2b:65::/32fc2b:65:ffff:ffff:ffff:ffff:ffff:ffff
103fc2b:66::/32fc2b:66:ffff:ffff:ffff:ffff:ffff:ffff
104fc2b:67::/32fc2b:67:ffff:ffff:ffff:ffff:ffff:ffff
105fc2b:68::/32fc2b:68:ffff:ffff:ffff:ffff:ffff:ffff
106fc2b:69::/32fc2b:69:ffff:ffff:ffff:ffff:ffff:ffff
107fc2b:6a::/32fc2b:6a:ffff:ffff:ffff:ffff:ffff:ffff
108fc2b:6b::/32fc2b:6b:ffff:ffff:ffff:ffff:ffff:ffff
109fc2b:6c::/32fc2b:6c:ffff:ffff:ffff:ffff:ffff:ffff
110fc2b:6d::/32fc2b:6d:ffff:ffff:ffff:ffff:ffff:ffff
111fc2b:6e::/32fc2b:6e:ffff:ffff:ffff:ffff:ffff:ffff
112fc2b:6f::/32fc2b:6f:ffff:ffff:ffff:ffff:ffff:ffff
113fc2b:70::/32fc2b:70:ffff:ffff:ffff:ffff:ffff:ffff
114fc2b:71::/32fc2b:71:ffff:ffff:ffff:ffff:ffff:ffff
115fc2b:72::/32fc2b:72:ffff:ffff:ffff:ffff:ffff:ffff
116fc2b:73::/32fc2b:73:ffff:ffff:ffff:ffff:ffff:ffff
117fc2b:74::/32fc2b:74:ffff:ffff:ffff:ffff:ffff:ffff
118fc2b:75::/32fc2b:75:ffff:ffff:ffff:ffff:ffff:ffff
119fc2b:76::/32fc2b:76:ffff:ffff:ffff:ffff:ffff:ffff
120fc2b:77::/32fc2b:77:ffff:ffff:ffff:ffff:ffff:ffff
121fc2b:78::/32fc2b:78:ffff:ffff:ffff:ffff:ffff:ffff
122fc2b:79::/32fc2b:79:ffff:ffff:ffff:ffff:ffff:ffff
123fc2b:7a::/32fc2b:7a:ffff:ffff:ffff:ffff:ffff:ffff
124fc2b:7b::/32fc2b:7b:ffff:ffff:ffff:ffff:ffff:ffff
125fc2b:7c::/32fc2b:7c:ffff:ffff:ffff:ffff:ffff:ffff
126fc2b:7d::/32fc2b:7d:ffff:ffff:ffff:ffff:ffff:ffff
127fc2b:7e::/32fc2b:7e:ffff:ffff:ffff:ffff:ffff:ffff
128fc2b:7f::/32fc2b:7f:ffff:ffff:ffff:ffff:ffff:ffff
129fc2b:80::/32fc2b:80:ffff:ffff:ffff:ffff:ffff:ffff
130fc2b:81::/32fc2b:81:ffff:ffff:ffff:ffff:ffff:ffff
131fc2b:82::/32fc2b:82:ffff:ffff:ffff:ffff:ffff:ffff
132fc2b:83::/32fc2b:83:ffff:ffff:ffff:ffff:ffff:ffff
133fc2b:84::/32fc2b:84:ffff:ffff:ffff:ffff:ffff:ffff
134fc2b:85::/32fc2b:85:ffff:ffff:ffff:ffff:ffff:ffff
135fc2b:86::/32fc2b:86:ffff:ffff:ffff:ffff:ffff:ffff
136fc2b:87::/32fc2b:87:ffff:ffff:ffff:ffff:ffff:ffff
137fc2b:88::/32fc2b:88:ffff:ffff:ffff:ffff:ffff:ffff
138fc2b:89::/32fc2b:89:ffff:ffff:ffff:ffff:ffff:ffff
139fc2b:8a::/32fc2b:8a:ffff:ffff:ffff:ffff:ffff:ffff
140fc2b:8b::/32fc2b:8b:ffff:ffff:ffff:ffff:ffff:ffff
141fc2b:8c::/32fc2b:8c:ffff:ffff:ffff:ffff:ffff:ffff
142fc2b:8d::/32fc2b:8d:ffff:ffff:ffff:ffff:ffff:ffff
143fc2b:8e::/32fc2b:8e:ffff:ffff:ffff:ffff:ffff:ffff
144fc2b:8f::/32fc2b:8f:ffff:ffff:ffff:ffff:ffff:ffff
145fc2b:90::/32fc2b:90:ffff:ffff:ffff:ffff:ffff:ffff
146fc2b:91::/32fc2b:91:ffff:ffff:ffff:ffff:ffff:ffff
147fc2b:92::/32fc2b:92:ffff:ffff:ffff:ffff:ffff:ffff
148fc2b:93::/32fc2b:93:ffff:ffff:ffff:ffff:ffff:ffff
149fc2b:94::/32fc2b:94:ffff:ffff:ffff:ffff:ffff:ffff
150fc2b:95::/32fc2b:95:ffff:ffff:ffff:ffff:ffff:ffff
151fc2b:96::/32fc2b:96:ffff:ffff:ffff:ffff:ffff:ffff
152fc2b:97::/32fc2b:97:ffff:ffff:ffff:ffff:ffff:ffff
153fc2b:98::/32fc2b:98:ffff:ffff:ffff:ffff:ffff:ffff
154fc2b:99::/32fc2b:99:ffff:ffff:ffff:ffff:ffff:ffff
155fc2b:9a::/32fc2b:9a:ffff:ffff:ffff:ffff:ffff:ffff
156fc2b:9b::/32fc2b:9b:ffff:ffff:ffff:ffff:ffff:ffff
157fc2b:9c::/32fc2b:9c:ffff:ffff:ffff:ffff:ffff:ffff
158fc2b:9d::/32fc2b:9d:ffff:ffff:ffff:ffff:ffff:ffff
159fc2b:9e::/32fc2b:9e:ffff:ffff:ffff:ffff:ffff:ffff
160fc2b:9f::/32fc2b:9f:ffff:ffff:ffff:ffff:ffff:ffff
161fc2b:a0::/32fc2b:a0:ffff:ffff:ffff:ffff:ffff:ffff
162fc2b:a1::/32fc2b:a1:ffff:ffff:ffff:ffff:ffff:ffff
163fc2b:a2::/32fc2b:a2:ffff:ffff:ffff:ffff:ffff:ffff
164fc2b:a3::/32fc2b:a3:ffff:ffff:ffff:ffff:ffff:ffff
165fc2b:a4::/32fc2b:a4:ffff:ffff:ffff:ffff:ffff:ffff
166fc2b:a5::/32fc2b:a5:ffff:ffff:ffff:ffff:ffff:ffff
167fc2b:a6::/32fc2b:a6:ffff:ffff:ffff:ffff:ffff:ffff
168fc2b:a7::/32fc2b:a7:ffff:ffff:ffff:ffff:ffff:ffff
169fc2b:a8::/32fc2b:a8:ffff:ffff:ffff:ffff:ffff:ffff
170fc2b:a9::/32fc2b:a9:ffff:ffff:ffff:ffff:ffff:ffff
171fc2b:aa::/32fc2b:aa:ffff:ffff:ffff:ffff:ffff:ffff
172fc2b:ab::/32fc2b:ab:ffff:ffff:ffff:ffff:ffff:ffff
173fc2b:ac::/32fc2b:ac:ffff:ffff:ffff:ffff:ffff:ffff
174fc2b:ad::/32fc2b:ad:ffff:ffff:ffff:ffff:ffff:ffff
175fc2b:ae::/32fc2b:ae:ffff:ffff:ffff:ffff:ffff:ffff
176fc2b:af::/32fc2b:af:ffff:ffff:ffff:ffff:ffff:ffff
177fc2b:b0::/32fc2b:b0:ffff:ffff:ffff:ffff:ffff:ffff
178fc2b:b1::/32fc2b:b1:ffff:ffff:ffff:ffff:ffff:ffff
179fc2b:b2::/32fc2b:b2:ffff:ffff:ffff:ffff:ffff:ffff
180fc2b:b3::/32fc2b:b3:ffff:ffff:ffff:ffff:ffff:ffff
181fc2b:b4::/32fc2b:b4:ffff:ffff:ffff:ffff:ffff:ffff
182fc2b:b5::/32fc2b:b5:ffff:ffff:ffff:ffff:ffff:ffff
183fc2b:b6::/32fc2b:b6:ffff:ffff:ffff:ffff:ffff:ffff
184fc2b:b7::/32fc2b:b7:ffff:ffff:ffff:ffff:ffff:ffff
185fc2b:b8::/32fc2b:b8:ffff:ffff:ffff:ffff:ffff:ffff
186fc2b:b9::/32fc2b:b9:ffff:ffff:ffff:ffff:ffff:ffff
187fc2b:ba::/32fc2b:ba:ffff:ffff:ffff:ffff:ffff:ffff
188fc2b:bb::/32fc2b:bb:ffff:ffff:ffff:ffff:ffff:ffff
189fc2b:bc::/32fc2b:bc:ffff:ffff:ffff:ffff:ffff:ffff
190fc2b:bd::/32fc2b:bd:ffff:ffff:ffff:ffff:ffff:ffff
191fc2b:be::/32fc2b:be:ffff:ffff:ffff:ffff:ffff:ffff
192fc2b:bf::/32fc2b:bf:ffff:ffff:ffff:ffff:ffff:ffff
193fc2b:c0::/32fc2b:c0:ffff:ffff:ffff:ffff:ffff:ffff
194fc2b:c1::/32fc2b:c1:ffff:ffff:ffff:ffff:ffff:ffff
195fc2b:c2::/32fc2b:c2:ffff:ffff:ffff:ffff:ffff:ffff
196fc2b:c3::/32fc2b:c3:ffff:ffff:ffff:ffff:ffff:ffff
197fc2b:c4::/32fc2b:c4:ffff:ffff:ffff:ffff:ffff:ffff
198fc2b:c5::/32fc2b:c5:ffff:ffff:ffff:ffff:ffff:ffff
199fc2b:c6::/32fc2b:c6:ffff:ffff:ffff:ffff:ffff:ffff
200fc2b:c7::/32fc2b:c7:ffff:ffff:ffff:ffff:ffff:ffff
201fc2b:c8::/32fc2b:c8:ffff:ffff:ffff:ffff:ffff:ffff
202fc2b:c9::/32fc2b:c9:ffff:ffff:ffff:ffff:ffff:ffff
203fc2b:ca::/32fc2b:ca:ffff:ffff:ffff:ffff:ffff:ffff
204fc2b:cb::/32fc2b:cb:ffff:ffff:ffff:ffff:ffff:ffff
205fc2b:cc::/32fc2b:cc:ffff:ffff:ffff:ffff:ffff:ffff
206fc2b:cd::/32fc2b:cd:ffff:ffff:ffff:ffff:ffff:ffff
207fc2b:ce::/32fc2b:ce:ffff:ffff:ffff:ffff:ffff:ffff
208fc2b:cf::/32fc2b:cf:ffff:ffff:ffff:ffff:ffff:ffff
209fc2b:d0::/32fc2b:d0:ffff:ffff:ffff:ffff:ffff:ffff
210fc2b:d1::/32fc2b:d1:ffff:ffff:ffff:ffff:ffff:ffff
211fc2b:d2::/32fc2b:d2:ffff:ffff:ffff:ffff:ffff:ffff
212fc2b:d3::/32fc2b:d3:ffff:ffff:ffff:ffff:ffff:ffff
213fc2b:d4::/32fc2b:d4:ffff:ffff:ffff:ffff:ffff:ffff
214fc2b:d5::/32fc2b:d5:ffff:ffff:ffff:ffff:ffff:ffff
215fc2b:d6::/32fc2b:d6:ffff:ffff:ffff:ffff:ffff:ffff
216fc2b:d7::/32fc2b:d7:ffff:ffff:ffff:ffff:ffff:ffff
217fc2b:d8::/32fc2b:d8:ffff:ffff:ffff:ffff:ffff:ffff
218fc2b:d9::/32fc2b:d9:ffff:ffff:ffff:ffff:ffff:ffff
219fc2b:da::/32fc2b:da:ffff:ffff:ffff:ffff:ffff:ffff
220fc2b:db::/32fc2b:db:ffff:ffff:ffff:ffff:ffff:ffff
221fc2b:dc::/32fc2b:dc:ffff:ffff:ffff:ffff:ffff:ffff
222fc2b:dd::/32fc2b:dd:ffff:ffff:ffff:ffff:ffff:ffff
223fc2b:de::/32fc2b:de:ffff:ffff:ffff:ffff:ffff:ffff
224fc2b:df::/32fc2b:df:ffff:ffff:ffff:ffff:ffff:ffff
225fc2b:e0::/32fc2b:e0:ffff:ffff:ffff:ffff:ffff:ffff
226fc2b:e1::/32fc2b:e1:ffff:ffff:ffff:ffff:ffff:ffff
227fc2b:e2::/32fc2b:e2:ffff:ffff:ffff:ffff:ffff:ffff
228fc2b:e3::/32fc2b:e3:ffff:ffff:ffff:ffff:ffff:ffff
229fc2b:e4::/32fc2b:e4:ffff:ffff:ffff:ffff:ffff:ffff
230fc2b:e5::/32fc2b:e5:ffff:ffff:ffff:ffff:ffff:ffff
231fc2b:e6::/32fc2b:e6:ffff:ffff:ffff:ffff:ffff:ffff
232fc2b:e7::/32fc2b:e7:ffff:ffff:ffff:ffff:ffff:ffff
233fc2b:e8::/32fc2b:e8:ffff:ffff:ffff:ffff:ffff:ffff
234fc2b:e9::/32fc2b:e9:ffff:ffff:ffff:ffff:ffff:ffff
235fc2b:ea::/32fc2b:ea:ffff:ffff:ffff:ffff:ffff:ffff
236fc2b:eb::/32fc2b:eb:ffff:ffff:ffff:ffff:ffff:ffff
237fc2b:ec::/32fc2b:ec:ffff:ffff:ffff:ffff:ffff:ffff
238fc2b:ed::/32fc2b:ed:ffff:ffff:ffff:ffff:ffff:ffff
239fc2b:ee::/32fc2b:ee:ffff:ffff:ffff:ffff:ffff:ffff
240fc2b:ef::/32fc2b:ef:ffff:ffff:ffff:ffff:ffff:ffff
241fc2b:f0::/32fc2b:f0:ffff:ffff:ffff:ffff:ffff:ffff
242fc2b:f1::/32fc2b:f1:ffff:ffff:ffff:ffff:ffff:ffff
243fc2b:f2::/32fc2b:f2:ffff:ffff:ffff:ffff:ffff:ffff
244fc2b:f3::/32fc2b:f3:ffff:ffff:ffff:ffff:ffff:ffff
245fc2b:f4::/32fc2b:f4:ffff:ffff:ffff:ffff:ffff:ffff
246fc2b:f5::/32fc2b:f5:ffff:ffff:ffff:ffff:ffff:ffff
247fc2b:f6::/32fc2b:f6:ffff:ffff:ffff:ffff:ffff:ffff
248fc2b:f7::/32fc2b:f7:ffff:ffff:ffff:ffff:ffff:ffff
249fc2b:f8::/32fc2b:f8:ffff:ffff:ffff:ffff:ffff:ffff
250fc2b:f9::/32fc2b:f9:ffff:ffff:ffff:ffff:ffff:ffff
251fc2b:fa::/32fc2b:fa:ffff:ffff:ffff:ffff:ffff:ffff
252fc2b:fb::/32fc2b:fb:ffff:ffff:ffff:ffff:ffff:ffff
253fc2b:fc::/32fc2b:fc:ffff:ffff:ffff:ffff:ffff:ffff
254fc2b:fd::/32fc2b:fd:ffff:ffff:ffff:ffff:ffff:ffff
255fc2b:fe::/32fc2b:fe:ffff:ffff:ffff:ffff:ffff:ffff
256fc2b:ff::/32fc2b: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.