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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
321d::/16
First address
321d::
Last address
321d: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
321d:0000:0000:0000:0000:0000:0000:0000
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zone
d.1.2.3.ip6.arpa
Split into smaller subnets/32
/17 (2)/18 (4)/19 (8)/20 (16)/24 (256)/28 (4,096)/32 (65,536)

321d::/16 makes 65,536 subnets of /32; the first 256 are listed.

Subnets
#SubnetLast address
1321d::/32321d:0:ffff:ffff:ffff:ffff:ffff:ffff
2321d:1::/32321d:1:ffff:ffff:ffff:ffff:ffff:ffff
3321d:2::/32321d:2:ffff:ffff:ffff:ffff:ffff:ffff
4321d:3::/32321d:3:ffff:ffff:ffff:ffff:ffff:ffff
5321d:4::/32321d:4:ffff:ffff:ffff:ffff:ffff:ffff
6321d:5::/32321d:5:ffff:ffff:ffff:ffff:ffff:ffff
7321d:6::/32321d:6:ffff:ffff:ffff:ffff:ffff:ffff
8321d:7::/32321d:7:ffff:ffff:ffff:ffff:ffff:ffff
9321d:8::/32321d:8:ffff:ffff:ffff:ffff:ffff:ffff
10321d:9::/32321d:9:ffff:ffff:ffff:ffff:ffff:ffff
11321d:a::/32321d:a:ffff:ffff:ffff:ffff:ffff:ffff
12321d:b::/32321d:b:ffff:ffff:ffff:ffff:ffff:ffff
13321d:c::/32321d:c:ffff:ffff:ffff:ffff:ffff:ffff
14321d:d::/32321d:d:ffff:ffff:ffff:ffff:ffff:ffff
15321d:e::/32321d:e:ffff:ffff:ffff:ffff:ffff:ffff
16321d:f::/32321d:f:ffff:ffff:ffff:ffff:ffff:ffff
17321d:10::/32321d:10:ffff:ffff:ffff:ffff:ffff:ffff
18321d:11::/32321d:11:ffff:ffff:ffff:ffff:ffff:ffff
19321d:12::/32321d:12:ffff:ffff:ffff:ffff:ffff:ffff
20321d:13::/32321d:13:ffff:ffff:ffff:ffff:ffff:ffff
21321d:14::/32321d:14:ffff:ffff:ffff:ffff:ffff:ffff
22321d:15::/32321d:15:ffff:ffff:ffff:ffff:ffff:ffff
23321d:16::/32321d:16:ffff:ffff:ffff:ffff:ffff:ffff
24321d:17::/32321d:17:ffff:ffff:ffff:ffff:ffff:ffff
25321d:18::/32321d:18:ffff:ffff:ffff:ffff:ffff:ffff
26321d:19::/32321d:19:ffff:ffff:ffff:ffff:ffff:ffff
27321d:1a::/32321d:1a:ffff:ffff:ffff:ffff:ffff:ffff
28321d:1b::/32321d:1b:ffff:ffff:ffff:ffff:ffff:ffff
29321d:1c::/32321d:1c:ffff:ffff:ffff:ffff:ffff:ffff
30321d:1d::/32321d:1d:ffff:ffff:ffff:ffff:ffff:ffff
31321d:1e::/32321d:1e:ffff:ffff:ffff:ffff:ffff:ffff
32321d:1f::/32321d:1f:ffff:ffff:ffff:ffff:ffff:ffff
33321d:20::/32321d:20:ffff:ffff:ffff:ffff:ffff:ffff
34321d:21::/32321d:21:ffff:ffff:ffff:ffff:ffff:ffff
35321d:22::/32321d:22:ffff:ffff:ffff:ffff:ffff:ffff
36321d:23::/32321d:23:ffff:ffff:ffff:ffff:ffff:ffff
37321d:24::/32321d:24:ffff:ffff:ffff:ffff:ffff:ffff
38321d:25::/32321d:25:ffff:ffff:ffff:ffff:ffff:ffff
39321d:26::/32321d:26:ffff:ffff:ffff:ffff:ffff:ffff
40321d:27::/32321d:27:ffff:ffff:ffff:ffff:ffff:ffff
41321d:28::/32321d:28:ffff:ffff:ffff:ffff:ffff:ffff
42321d:29::/32321d:29:ffff:ffff:ffff:ffff:ffff:ffff
43321d:2a::/32321d:2a:ffff:ffff:ffff:ffff:ffff:ffff
44321d:2b::/32321d:2b:ffff:ffff:ffff:ffff:ffff:ffff
45321d:2c::/32321d:2c:ffff:ffff:ffff:ffff:ffff:ffff
46321d:2d::/32321d:2d:ffff:ffff:ffff:ffff:ffff:ffff
47321d:2e::/32321d:2e:ffff:ffff:ffff:ffff:ffff:ffff
48321d:2f::/32321d:2f:ffff:ffff:ffff:ffff:ffff:ffff
49321d:30::/32321d:30:ffff:ffff:ffff:ffff:ffff:ffff
50321d:31::/32321d:31:ffff:ffff:ffff:ffff:ffff:ffff
51321d:32::/32321d:32:ffff:ffff:ffff:ffff:ffff:ffff
52321d:33::/32321d:33:ffff:ffff:ffff:ffff:ffff:ffff
53321d:34::/32321d:34:ffff:ffff:ffff:ffff:ffff:ffff
54321d:35::/32321d:35:ffff:ffff:ffff:ffff:ffff:ffff
55321d:36::/32321d:36:ffff:ffff:ffff:ffff:ffff:ffff
56321d:37::/32321d:37:ffff:ffff:ffff:ffff:ffff:ffff
57321d:38::/32321d:38:ffff:ffff:ffff:ffff:ffff:ffff
58321d:39::/32321d:39:ffff:ffff:ffff:ffff:ffff:ffff
59321d:3a::/32321d:3a:ffff:ffff:ffff:ffff:ffff:ffff
60321d:3b::/32321d:3b:ffff:ffff:ffff:ffff:ffff:ffff
61321d:3c::/32321d:3c:ffff:ffff:ffff:ffff:ffff:ffff
62321d:3d::/32321d:3d:ffff:ffff:ffff:ffff:ffff:ffff
63321d:3e::/32321d:3e:ffff:ffff:ffff:ffff:ffff:ffff
64321d:3f::/32321d:3f:ffff:ffff:ffff:ffff:ffff:ffff
65321d:40::/32321d:40:ffff:ffff:ffff:ffff:ffff:ffff
66321d:41::/32321d:41:ffff:ffff:ffff:ffff:ffff:ffff
67321d:42::/32321d:42:ffff:ffff:ffff:ffff:ffff:ffff
68321d:43::/32321d:43:ffff:ffff:ffff:ffff:ffff:ffff
69321d:44::/32321d:44:ffff:ffff:ffff:ffff:ffff:ffff
70321d:45::/32321d:45:ffff:ffff:ffff:ffff:ffff:ffff
71321d:46::/32321d:46:ffff:ffff:ffff:ffff:ffff:ffff
72321d:47::/32321d:47:ffff:ffff:ffff:ffff:ffff:ffff
73321d:48::/32321d:48:ffff:ffff:ffff:ffff:ffff:ffff
74321d:49::/32321d:49:ffff:ffff:ffff:ffff:ffff:ffff
75321d:4a::/32321d:4a:ffff:ffff:ffff:ffff:ffff:ffff
76321d:4b::/32321d:4b:ffff:ffff:ffff:ffff:ffff:ffff
77321d:4c::/32321d:4c:ffff:ffff:ffff:ffff:ffff:ffff
78321d:4d::/32321d:4d:ffff:ffff:ffff:ffff:ffff:ffff
79321d:4e::/32321d:4e:ffff:ffff:ffff:ffff:ffff:ffff
80321d:4f::/32321d:4f:ffff:ffff:ffff:ffff:ffff:ffff
81321d:50::/32321d:50:ffff:ffff:ffff:ffff:ffff:ffff
82321d:51::/32321d:51:ffff:ffff:ffff:ffff:ffff:ffff
83321d:52::/32321d:52:ffff:ffff:ffff:ffff:ffff:ffff
84321d:53::/32321d:53:ffff:ffff:ffff:ffff:ffff:ffff
85321d:54::/32321d:54:ffff:ffff:ffff:ffff:ffff:ffff
86321d:55::/32321d:55:ffff:ffff:ffff:ffff:ffff:ffff
87321d:56::/32321d:56:ffff:ffff:ffff:ffff:ffff:ffff
88321d:57::/32321d:57:ffff:ffff:ffff:ffff:ffff:ffff
89321d:58::/32321d:58:ffff:ffff:ffff:ffff:ffff:ffff
90321d:59::/32321d:59:ffff:ffff:ffff:ffff:ffff:ffff
91321d:5a::/32321d:5a:ffff:ffff:ffff:ffff:ffff:ffff
92321d:5b::/32321d:5b:ffff:ffff:ffff:ffff:ffff:ffff
93321d:5c::/32321d:5c:ffff:ffff:ffff:ffff:ffff:ffff
94321d:5d::/32321d:5d:ffff:ffff:ffff:ffff:ffff:ffff
95321d:5e::/32321d:5e:ffff:ffff:ffff:ffff:ffff:ffff
96321d:5f::/32321d:5f:ffff:ffff:ffff:ffff:ffff:ffff
97321d:60::/32321d:60:ffff:ffff:ffff:ffff:ffff:ffff
98321d:61::/32321d:61:ffff:ffff:ffff:ffff:ffff:ffff
99321d:62::/32321d:62:ffff:ffff:ffff:ffff:ffff:ffff
100321d:63::/32321d:63:ffff:ffff:ffff:ffff:ffff:ffff
101321d:64::/32321d:64:ffff:ffff:ffff:ffff:ffff:ffff
102321d:65::/32321d:65:ffff:ffff:ffff:ffff:ffff:ffff
103321d:66::/32321d:66:ffff:ffff:ffff:ffff:ffff:ffff
104321d:67::/32321d:67:ffff:ffff:ffff:ffff:ffff:ffff
105321d:68::/32321d:68:ffff:ffff:ffff:ffff:ffff:ffff
106321d:69::/32321d:69:ffff:ffff:ffff:ffff:ffff:ffff
107321d:6a::/32321d:6a:ffff:ffff:ffff:ffff:ffff:ffff
108321d:6b::/32321d:6b:ffff:ffff:ffff:ffff:ffff:ffff
109321d:6c::/32321d:6c:ffff:ffff:ffff:ffff:ffff:ffff
110321d:6d::/32321d:6d:ffff:ffff:ffff:ffff:ffff:ffff
111321d:6e::/32321d:6e:ffff:ffff:ffff:ffff:ffff:ffff
112321d:6f::/32321d:6f:ffff:ffff:ffff:ffff:ffff:ffff
113321d:70::/32321d:70:ffff:ffff:ffff:ffff:ffff:ffff
114321d:71::/32321d:71:ffff:ffff:ffff:ffff:ffff:ffff
115321d:72::/32321d:72:ffff:ffff:ffff:ffff:ffff:ffff
116321d:73::/32321d:73:ffff:ffff:ffff:ffff:ffff:ffff
117321d:74::/32321d:74:ffff:ffff:ffff:ffff:ffff:ffff
118321d:75::/32321d:75:ffff:ffff:ffff:ffff:ffff:ffff
119321d:76::/32321d:76:ffff:ffff:ffff:ffff:ffff:ffff
120321d:77::/32321d:77:ffff:ffff:ffff:ffff:ffff:ffff
121321d:78::/32321d:78:ffff:ffff:ffff:ffff:ffff:ffff
122321d:79::/32321d:79:ffff:ffff:ffff:ffff:ffff:ffff
123321d:7a::/32321d:7a:ffff:ffff:ffff:ffff:ffff:ffff
124321d:7b::/32321d:7b:ffff:ffff:ffff:ffff:ffff:ffff
125321d:7c::/32321d:7c:ffff:ffff:ffff:ffff:ffff:ffff
126321d:7d::/32321d:7d:ffff:ffff:ffff:ffff:ffff:ffff
127321d:7e::/32321d:7e:ffff:ffff:ffff:ffff:ffff:ffff
128321d:7f::/32321d:7f:ffff:ffff:ffff:ffff:ffff:ffff
129321d:80::/32321d:80:ffff:ffff:ffff:ffff:ffff:ffff
130321d:81::/32321d:81:ffff:ffff:ffff:ffff:ffff:ffff
131321d:82::/32321d:82:ffff:ffff:ffff:ffff:ffff:ffff
132321d:83::/32321d:83:ffff:ffff:ffff:ffff:ffff:ffff
133321d:84::/32321d:84:ffff:ffff:ffff:ffff:ffff:ffff
134321d:85::/32321d:85:ffff:ffff:ffff:ffff:ffff:ffff
135321d:86::/32321d:86:ffff:ffff:ffff:ffff:ffff:ffff
136321d:87::/32321d:87:ffff:ffff:ffff:ffff:ffff:ffff
137321d:88::/32321d:88:ffff:ffff:ffff:ffff:ffff:ffff
138321d:89::/32321d:89:ffff:ffff:ffff:ffff:ffff:ffff
139321d:8a::/32321d:8a:ffff:ffff:ffff:ffff:ffff:ffff
140321d:8b::/32321d:8b:ffff:ffff:ffff:ffff:ffff:ffff
141321d:8c::/32321d:8c:ffff:ffff:ffff:ffff:ffff:ffff
142321d:8d::/32321d:8d:ffff:ffff:ffff:ffff:ffff:ffff
143321d:8e::/32321d:8e:ffff:ffff:ffff:ffff:ffff:ffff
144321d:8f::/32321d:8f:ffff:ffff:ffff:ffff:ffff:ffff
145321d:90::/32321d:90:ffff:ffff:ffff:ffff:ffff:ffff
146321d:91::/32321d:91:ffff:ffff:ffff:ffff:ffff:ffff
147321d:92::/32321d:92:ffff:ffff:ffff:ffff:ffff:ffff
148321d:93::/32321d:93:ffff:ffff:ffff:ffff:ffff:ffff
149321d:94::/32321d:94:ffff:ffff:ffff:ffff:ffff:ffff
150321d:95::/32321d:95:ffff:ffff:ffff:ffff:ffff:ffff
151321d:96::/32321d:96:ffff:ffff:ffff:ffff:ffff:ffff
152321d:97::/32321d:97:ffff:ffff:ffff:ffff:ffff:ffff
153321d:98::/32321d:98:ffff:ffff:ffff:ffff:ffff:ffff
154321d:99::/32321d:99:ffff:ffff:ffff:ffff:ffff:ffff
155321d:9a::/32321d:9a:ffff:ffff:ffff:ffff:ffff:ffff
156321d:9b::/32321d:9b:ffff:ffff:ffff:ffff:ffff:ffff
157321d:9c::/32321d:9c:ffff:ffff:ffff:ffff:ffff:ffff
158321d:9d::/32321d:9d:ffff:ffff:ffff:ffff:ffff:ffff
159321d:9e::/32321d:9e:ffff:ffff:ffff:ffff:ffff:ffff
160321d:9f::/32321d:9f:ffff:ffff:ffff:ffff:ffff:ffff
161321d:a0::/32321d:a0:ffff:ffff:ffff:ffff:ffff:ffff
162321d:a1::/32321d:a1:ffff:ffff:ffff:ffff:ffff:ffff
163321d:a2::/32321d:a2:ffff:ffff:ffff:ffff:ffff:ffff
164321d:a3::/32321d:a3:ffff:ffff:ffff:ffff:ffff:ffff
165321d:a4::/32321d:a4:ffff:ffff:ffff:ffff:ffff:ffff
166321d:a5::/32321d:a5:ffff:ffff:ffff:ffff:ffff:ffff
167321d:a6::/32321d:a6:ffff:ffff:ffff:ffff:ffff:ffff
168321d:a7::/32321d:a7:ffff:ffff:ffff:ffff:ffff:ffff
169321d:a8::/32321d:a8:ffff:ffff:ffff:ffff:ffff:ffff
170321d:a9::/32321d:a9:ffff:ffff:ffff:ffff:ffff:ffff
171321d:aa::/32321d:aa:ffff:ffff:ffff:ffff:ffff:ffff
172321d:ab::/32321d:ab:ffff:ffff:ffff:ffff:ffff:ffff
173321d:ac::/32321d:ac:ffff:ffff:ffff:ffff:ffff:ffff
174321d:ad::/32321d:ad:ffff:ffff:ffff:ffff:ffff:ffff
175321d:ae::/32321d:ae:ffff:ffff:ffff:ffff:ffff:ffff
176321d:af::/32321d:af:ffff:ffff:ffff:ffff:ffff:ffff
177321d:b0::/32321d:b0:ffff:ffff:ffff:ffff:ffff:ffff
178321d:b1::/32321d:b1:ffff:ffff:ffff:ffff:ffff:ffff
179321d:b2::/32321d:b2:ffff:ffff:ffff:ffff:ffff:ffff
180321d:b3::/32321d:b3:ffff:ffff:ffff:ffff:ffff:ffff
181321d:b4::/32321d:b4:ffff:ffff:ffff:ffff:ffff:ffff
182321d:b5::/32321d:b5:ffff:ffff:ffff:ffff:ffff:ffff
183321d:b6::/32321d:b6:ffff:ffff:ffff:ffff:ffff:ffff
184321d:b7::/32321d:b7:ffff:ffff:ffff:ffff:ffff:ffff
185321d:b8::/32321d:b8:ffff:ffff:ffff:ffff:ffff:ffff
186321d:b9::/32321d:b9:ffff:ffff:ffff:ffff:ffff:ffff
187321d:ba::/32321d:ba:ffff:ffff:ffff:ffff:ffff:ffff
188321d:bb::/32321d:bb:ffff:ffff:ffff:ffff:ffff:ffff
189321d:bc::/32321d:bc:ffff:ffff:ffff:ffff:ffff:ffff
190321d:bd::/32321d:bd:ffff:ffff:ffff:ffff:ffff:ffff
191321d:be::/32321d:be:ffff:ffff:ffff:ffff:ffff:ffff
192321d:bf::/32321d:bf:ffff:ffff:ffff:ffff:ffff:ffff
193321d:c0::/32321d:c0:ffff:ffff:ffff:ffff:ffff:ffff
194321d:c1::/32321d:c1:ffff:ffff:ffff:ffff:ffff:ffff
195321d:c2::/32321d:c2:ffff:ffff:ffff:ffff:ffff:ffff
196321d:c3::/32321d:c3:ffff:ffff:ffff:ffff:ffff:ffff
197321d:c4::/32321d:c4:ffff:ffff:ffff:ffff:ffff:ffff
198321d:c5::/32321d:c5:ffff:ffff:ffff:ffff:ffff:ffff
199321d:c6::/32321d:c6:ffff:ffff:ffff:ffff:ffff:ffff
200321d:c7::/32321d:c7:ffff:ffff:ffff:ffff:ffff:ffff
201321d:c8::/32321d:c8:ffff:ffff:ffff:ffff:ffff:ffff
202321d:c9::/32321d:c9:ffff:ffff:ffff:ffff:ffff:ffff
203321d:ca::/32321d:ca:ffff:ffff:ffff:ffff:ffff:ffff
204321d:cb::/32321d:cb:ffff:ffff:ffff:ffff:ffff:ffff
205321d:cc::/32321d:cc:ffff:ffff:ffff:ffff:ffff:ffff
206321d:cd::/32321d:cd:ffff:ffff:ffff:ffff:ffff:ffff
207321d:ce::/32321d:ce:ffff:ffff:ffff:ffff:ffff:ffff
208321d:cf::/32321d:cf:ffff:ffff:ffff:ffff:ffff:ffff
209321d:d0::/32321d:d0:ffff:ffff:ffff:ffff:ffff:ffff
210321d:d1::/32321d:d1:ffff:ffff:ffff:ffff:ffff:ffff
211321d:d2::/32321d:d2:ffff:ffff:ffff:ffff:ffff:ffff
212321d:d3::/32321d:d3:ffff:ffff:ffff:ffff:ffff:ffff
213321d:d4::/32321d:d4:ffff:ffff:ffff:ffff:ffff:ffff
214321d:d5::/32321d:d5:ffff:ffff:ffff:ffff:ffff:ffff
215321d:d6::/32321d:d6:ffff:ffff:ffff:ffff:ffff:ffff
216321d:d7::/32321d:d7:ffff:ffff:ffff:ffff:ffff:ffff
217321d:d8::/32321d:d8:ffff:ffff:ffff:ffff:ffff:ffff
218321d:d9::/32321d:d9:ffff:ffff:ffff:ffff:ffff:ffff
219321d:da::/32321d:da:ffff:ffff:ffff:ffff:ffff:ffff
220321d:db::/32321d:db:ffff:ffff:ffff:ffff:ffff:ffff
221321d:dc::/32321d:dc:ffff:ffff:ffff:ffff:ffff:ffff
222321d:dd::/32321d:dd:ffff:ffff:ffff:ffff:ffff:ffff
223321d:de::/32321d:de:ffff:ffff:ffff:ffff:ffff:ffff
224321d:df::/32321d:df:ffff:ffff:ffff:ffff:ffff:ffff
225321d:e0::/32321d:e0:ffff:ffff:ffff:ffff:ffff:ffff
226321d:e1::/32321d:e1:ffff:ffff:ffff:ffff:ffff:ffff
227321d:e2::/32321d:e2:ffff:ffff:ffff:ffff:ffff:ffff
228321d:e3::/32321d:e3:ffff:ffff:ffff:ffff:ffff:ffff
229321d:e4::/32321d:e4:ffff:ffff:ffff:ffff:ffff:ffff
230321d:e5::/32321d:e5:ffff:ffff:ffff:ffff:ffff:ffff
231321d:e6::/32321d:e6:ffff:ffff:ffff:ffff:ffff:ffff
232321d:e7::/32321d:e7:ffff:ffff:ffff:ffff:ffff:ffff
233321d:e8::/32321d:e8:ffff:ffff:ffff:ffff:ffff:ffff
234321d:e9::/32321d:e9:ffff:ffff:ffff:ffff:ffff:ffff
235321d:ea::/32321d:ea:ffff:ffff:ffff:ffff:ffff:ffff
236321d:eb::/32321d:eb:ffff:ffff:ffff:ffff:ffff:ffff
237321d:ec::/32321d:ec:ffff:ffff:ffff:ffff:ffff:ffff
238321d:ed::/32321d:ed:ffff:ffff:ffff:ffff:ffff:ffff
239321d:ee::/32321d:ee:ffff:ffff:ffff:ffff:ffff:ffff
240321d:ef::/32321d:ef:ffff:ffff:ffff:ffff:ffff:ffff
241321d:f0::/32321d:f0:ffff:ffff:ffff:ffff:ffff:ffff
242321d:f1::/32321d:f1:ffff:ffff:ffff:ffff:ffff:ffff
243321d:f2::/32321d:f2:ffff:ffff:ffff:ffff:ffff:ffff
244321d:f3::/32321d:f3:ffff:ffff:ffff:ffff:ffff:ffff
245321d:f4::/32321d:f4:ffff:ffff:ffff:ffff:ffff:ffff
246321d:f5::/32321d:f5:ffff:ffff:ffff:ffff:ffff:ffff
247321d:f6::/32321d:f6:ffff:ffff:ffff:ffff:ffff:ffff
248321d:f7::/32321d:f7:ffff:ffff:ffff:ffff:ffff:ffff
249321d:f8::/32321d:f8:ffff:ffff:ffff:ffff:ffff:ffff
250321d:f9::/32321d:f9:ffff:ffff:ffff:ffff:ffff:ffff
251321d:fa::/32321d:fa:ffff:ffff:ffff:ffff:ffff:ffff
252321d:fb::/32321d:fb:ffff:ffff:ffff:ffff:ffff:ffff
253321d:fc::/32321d:fc:ffff:ffff:ffff:ffff:ffff:ffff
254321d:fd::/32321d:fd:ffff:ffff:ffff:ffff:ffff:ffff
255321d:fe::/32321d:fe:ffff:ffff:ffff:ffff:ffff:ffff
256321d:ff::/32321d: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.