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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/20
Addresses2^108
/64 networks2^44
Network
fc41::/20
First address
fc41::
Last address
fc41:fff:ffff:ffff:ffff:ffff:ffff:ffff
Addresses
324,518,553,658,426,726,783,156,020,576,256 (2^108)
/64 networks (LANs)
17,592,186,044,416 (2^44)
Full form
fc41:0000:0000:0000:0000:0000:0000:0000
Type
Unique local (ULA) fc00::/7
Private IPv6, like RFC 1918; usually fd00::/8
Reverse DNS zone
0.1.4.c.f.ip6.arpa
Split into smaller subnets/36
/21 (2)/22 (4)/23 (8)/24 (16)/28 (256)/32 (4,096)/36 (65,536)

fc41::/20 makes 65,536 subnets of /36; the first 256 are listed.

Subnets
#SubnetLast address
1fc41::/36fc41:0:fff:ffff:ffff:ffff:ffff:ffff
2fc41:0:1000::/36fc41:0:1fff:ffff:ffff:ffff:ffff:ffff
3fc41:0:2000::/36fc41:0:2fff:ffff:ffff:ffff:ffff:ffff
4fc41:0:3000::/36fc41:0:3fff:ffff:ffff:ffff:ffff:ffff
5fc41:0:4000::/36fc41:0:4fff:ffff:ffff:ffff:ffff:ffff
6fc41:0:5000::/36fc41:0:5fff:ffff:ffff:ffff:ffff:ffff
7fc41:0:6000::/36fc41:0:6fff:ffff:ffff:ffff:ffff:ffff
8fc41:0:7000::/36fc41:0:7fff:ffff:ffff:ffff:ffff:ffff
9fc41:0:8000::/36fc41:0:8fff:ffff:ffff:ffff:ffff:ffff
10fc41:0:9000::/36fc41:0:9fff:ffff:ffff:ffff:ffff:ffff
11fc41:0:a000::/36fc41:0:afff:ffff:ffff:ffff:ffff:ffff
12fc41:0:b000::/36fc41:0:bfff:ffff:ffff:ffff:ffff:ffff
13fc41:0:c000::/36fc41:0:cfff:ffff:ffff:ffff:ffff:ffff
14fc41:0:d000::/36fc41:0:dfff:ffff:ffff:ffff:ffff:ffff
15fc41:0:e000::/36fc41:0:efff:ffff:ffff:ffff:ffff:ffff
16fc41:0:f000::/36fc41:0:ffff:ffff:ffff:ffff:ffff:ffff
17fc41:1::/36fc41:1:fff:ffff:ffff:ffff:ffff:ffff
18fc41:1:1000::/36fc41:1:1fff:ffff:ffff:ffff:ffff:ffff
19fc41:1:2000::/36fc41:1:2fff:ffff:ffff:ffff:ffff:ffff
20fc41:1:3000::/36fc41:1:3fff:ffff:ffff:ffff:ffff:ffff
21fc41:1:4000::/36fc41:1:4fff:ffff:ffff:ffff:ffff:ffff
22fc41:1:5000::/36fc41:1:5fff:ffff:ffff:ffff:ffff:ffff
23fc41:1:6000::/36fc41:1:6fff:ffff:ffff:ffff:ffff:ffff
24fc41:1:7000::/36fc41:1:7fff:ffff:ffff:ffff:ffff:ffff
25fc41:1:8000::/36fc41:1:8fff:ffff:ffff:ffff:ffff:ffff
26fc41:1:9000::/36fc41:1:9fff:ffff:ffff:ffff:ffff:ffff
27fc41:1:a000::/36fc41:1:afff:ffff:ffff:ffff:ffff:ffff
28fc41:1:b000::/36fc41:1:bfff:ffff:ffff:ffff:ffff:ffff
29fc41:1:c000::/36fc41:1:cfff:ffff:ffff:ffff:ffff:ffff
30fc41:1:d000::/36fc41:1:dfff:ffff:ffff:ffff:ffff:ffff
31fc41:1:e000::/36fc41:1:efff:ffff:ffff:ffff:ffff:ffff
32fc41:1:f000::/36fc41:1:ffff:ffff:ffff:ffff:ffff:ffff
33fc41:2::/36fc41:2:fff:ffff:ffff:ffff:ffff:ffff
34fc41:2:1000::/36fc41:2:1fff:ffff:ffff:ffff:ffff:ffff
35fc41:2:2000::/36fc41:2:2fff:ffff:ffff:ffff:ffff:ffff
36fc41:2:3000::/36fc41:2:3fff:ffff:ffff:ffff:ffff:ffff
37fc41:2:4000::/36fc41:2:4fff:ffff:ffff:ffff:ffff:ffff
38fc41:2:5000::/36fc41:2:5fff:ffff:ffff:ffff:ffff:ffff
39fc41:2:6000::/36fc41:2:6fff:ffff:ffff:ffff:ffff:ffff
40fc41:2:7000::/36fc41:2:7fff:ffff:ffff:ffff:ffff:ffff
41fc41:2:8000::/36fc41:2:8fff:ffff:ffff:ffff:ffff:ffff
42fc41:2:9000::/36fc41:2:9fff:ffff:ffff:ffff:ffff:ffff
43fc41:2:a000::/36fc41:2:afff:ffff:ffff:ffff:ffff:ffff
44fc41:2:b000::/36fc41:2:bfff:ffff:ffff:ffff:ffff:ffff
45fc41:2:c000::/36fc41:2:cfff:ffff:ffff:ffff:ffff:ffff
46fc41:2:d000::/36fc41:2:dfff:ffff:ffff:ffff:ffff:ffff
47fc41:2:e000::/36fc41:2:efff:ffff:ffff:ffff:ffff:ffff
48fc41:2:f000::/36fc41:2:ffff:ffff:ffff:ffff:ffff:ffff
49fc41:3::/36fc41:3:fff:ffff:ffff:ffff:ffff:ffff
50fc41:3:1000::/36fc41:3:1fff:ffff:ffff:ffff:ffff:ffff
51fc41:3:2000::/36fc41:3:2fff:ffff:ffff:ffff:ffff:ffff
52fc41:3:3000::/36fc41:3:3fff:ffff:ffff:ffff:ffff:ffff
53fc41:3:4000::/36fc41:3:4fff:ffff:ffff:ffff:ffff:ffff
54fc41:3:5000::/36fc41:3:5fff:ffff:ffff:ffff:ffff:ffff
55fc41:3:6000::/36fc41:3:6fff:ffff:ffff:ffff:ffff:ffff
56fc41:3:7000::/36fc41:3:7fff:ffff:ffff:ffff:ffff:ffff
57fc41:3:8000::/36fc41:3:8fff:ffff:ffff:ffff:ffff:ffff
58fc41:3:9000::/36fc41:3:9fff:ffff:ffff:ffff:ffff:ffff
59fc41:3:a000::/36fc41:3:afff:ffff:ffff:ffff:ffff:ffff
60fc41:3:b000::/36fc41:3:bfff:ffff:ffff:ffff:ffff:ffff
61fc41:3:c000::/36fc41:3:cfff:ffff:ffff:ffff:ffff:ffff
62fc41:3:d000::/36fc41:3:dfff:ffff:ffff:ffff:ffff:ffff
63fc41:3:e000::/36fc41:3:efff:ffff:ffff:ffff:ffff:ffff
64fc41:3:f000::/36fc41:3:ffff:ffff:ffff:ffff:ffff:ffff
65fc41:4::/36fc41:4:fff:ffff:ffff:ffff:ffff:ffff
66fc41:4:1000::/36fc41:4:1fff:ffff:ffff:ffff:ffff:ffff
67fc41:4:2000::/36fc41:4:2fff:ffff:ffff:ffff:ffff:ffff
68fc41:4:3000::/36fc41:4:3fff:ffff:ffff:ffff:ffff:ffff
69fc41:4:4000::/36fc41:4:4fff:ffff:ffff:ffff:ffff:ffff
70fc41:4:5000::/36fc41:4:5fff:ffff:ffff:ffff:ffff:ffff
71fc41:4:6000::/36fc41:4:6fff:ffff:ffff:ffff:ffff:ffff
72fc41:4:7000::/36fc41:4:7fff:ffff:ffff:ffff:ffff:ffff
73fc41:4:8000::/36fc41:4:8fff:ffff:ffff:ffff:ffff:ffff
74fc41:4:9000::/36fc41:4:9fff:ffff:ffff:ffff:ffff:ffff
75fc41:4:a000::/36fc41:4:afff:ffff:ffff:ffff:ffff:ffff
76fc41:4:b000::/36fc41:4:bfff:ffff:ffff:ffff:ffff:ffff
77fc41:4:c000::/36fc41:4:cfff:ffff:ffff:ffff:ffff:ffff
78fc41:4:d000::/36fc41:4:dfff:ffff:ffff:ffff:ffff:ffff
79fc41:4:e000::/36fc41:4:efff:ffff:ffff:ffff:ffff:ffff
80fc41:4:f000::/36fc41:4:ffff:ffff:ffff:ffff:ffff:ffff
81fc41:5::/36fc41:5:fff:ffff:ffff:ffff:ffff:ffff
82fc41:5:1000::/36fc41:5:1fff:ffff:ffff:ffff:ffff:ffff
83fc41:5:2000::/36fc41:5:2fff:ffff:ffff:ffff:ffff:ffff
84fc41:5:3000::/36fc41:5:3fff:ffff:ffff:ffff:ffff:ffff
85fc41:5:4000::/36fc41:5:4fff:ffff:ffff:ffff:ffff:ffff
86fc41:5:5000::/36fc41:5:5fff:ffff:ffff:ffff:ffff:ffff
87fc41:5:6000::/36fc41:5:6fff:ffff:ffff:ffff:ffff:ffff
88fc41:5:7000::/36fc41:5:7fff:ffff:ffff:ffff:ffff:ffff
89fc41:5:8000::/36fc41:5:8fff:ffff:ffff:ffff:ffff:ffff
90fc41:5:9000::/36fc41:5:9fff:ffff:ffff:ffff:ffff:ffff
91fc41:5:a000::/36fc41:5:afff:ffff:ffff:ffff:ffff:ffff
92fc41:5:b000::/36fc41:5:bfff:ffff:ffff:ffff:ffff:ffff
93fc41:5:c000::/36fc41:5:cfff:ffff:ffff:ffff:ffff:ffff
94fc41:5:d000::/36fc41:5:dfff:ffff:ffff:ffff:ffff:ffff
95fc41:5:e000::/36fc41:5:efff:ffff:ffff:ffff:ffff:ffff
96fc41:5:f000::/36fc41:5:ffff:ffff:ffff:ffff:ffff:ffff
97fc41:6::/36fc41:6:fff:ffff:ffff:ffff:ffff:ffff
98fc41:6:1000::/36fc41:6:1fff:ffff:ffff:ffff:ffff:ffff
99fc41:6:2000::/36fc41:6:2fff:ffff:ffff:ffff:ffff:ffff
100fc41:6:3000::/36fc41:6:3fff:ffff:ffff:ffff:ffff:ffff
101fc41:6:4000::/36fc41:6:4fff:ffff:ffff:ffff:ffff:ffff
102fc41:6:5000::/36fc41:6:5fff:ffff:ffff:ffff:ffff:ffff
103fc41:6:6000::/36fc41:6:6fff:ffff:ffff:ffff:ffff:ffff
104fc41:6:7000::/36fc41:6:7fff:ffff:ffff:ffff:ffff:ffff
105fc41:6:8000::/36fc41:6:8fff:ffff:ffff:ffff:ffff:ffff
106fc41:6:9000::/36fc41:6:9fff:ffff:ffff:ffff:ffff:ffff
107fc41:6:a000::/36fc41:6:afff:ffff:ffff:ffff:ffff:ffff
108fc41:6:b000::/36fc41:6:bfff:ffff:ffff:ffff:ffff:ffff
109fc41:6:c000::/36fc41:6:cfff:ffff:ffff:ffff:ffff:ffff
110fc41:6:d000::/36fc41:6:dfff:ffff:ffff:ffff:ffff:ffff
111fc41:6:e000::/36fc41:6:efff:ffff:ffff:ffff:ffff:ffff
112fc41:6:f000::/36fc41:6:ffff:ffff:ffff:ffff:ffff:ffff
113fc41:7::/36fc41:7:fff:ffff:ffff:ffff:ffff:ffff
114fc41:7:1000::/36fc41:7:1fff:ffff:ffff:ffff:ffff:ffff
115fc41:7:2000::/36fc41:7:2fff:ffff:ffff:ffff:ffff:ffff
116fc41:7:3000::/36fc41:7:3fff:ffff:ffff:ffff:ffff:ffff
117fc41:7:4000::/36fc41:7:4fff:ffff:ffff:ffff:ffff:ffff
118fc41:7:5000::/36fc41:7:5fff:ffff:ffff:ffff:ffff:ffff
119fc41:7:6000::/36fc41:7:6fff:ffff:ffff:ffff:ffff:ffff
120fc41:7:7000::/36fc41:7:7fff:ffff:ffff:ffff:ffff:ffff
121fc41:7:8000::/36fc41:7:8fff:ffff:ffff:ffff:ffff:ffff
122fc41:7:9000::/36fc41:7:9fff:ffff:ffff:ffff:ffff:ffff
123fc41:7:a000::/36fc41:7:afff:ffff:ffff:ffff:ffff:ffff
124fc41:7:b000::/36fc41:7:bfff:ffff:ffff:ffff:ffff:ffff
125fc41:7:c000::/36fc41:7:cfff:ffff:ffff:ffff:ffff:ffff
126fc41:7:d000::/36fc41:7:dfff:ffff:ffff:ffff:ffff:ffff
127fc41:7:e000::/36fc41:7:efff:ffff:ffff:ffff:ffff:ffff
128fc41:7:f000::/36fc41:7:ffff:ffff:ffff:ffff:ffff:ffff
129fc41:8::/36fc41:8:fff:ffff:ffff:ffff:ffff:ffff
130fc41:8:1000::/36fc41:8:1fff:ffff:ffff:ffff:ffff:ffff
131fc41:8:2000::/36fc41:8:2fff:ffff:ffff:ffff:ffff:ffff
132fc41:8:3000::/36fc41:8:3fff:ffff:ffff:ffff:ffff:ffff
133fc41:8:4000::/36fc41:8:4fff:ffff:ffff:ffff:ffff:ffff
134fc41:8:5000::/36fc41:8:5fff:ffff:ffff:ffff:ffff:ffff
135fc41:8:6000::/36fc41:8:6fff:ffff:ffff:ffff:ffff:ffff
136fc41:8:7000::/36fc41:8:7fff:ffff:ffff:ffff:ffff:ffff
137fc41:8:8000::/36fc41:8:8fff:ffff:ffff:ffff:ffff:ffff
138fc41:8:9000::/36fc41:8:9fff:ffff:ffff:ffff:ffff:ffff
139fc41:8:a000::/36fc41:8:afff:ffff:ffff:ffff:ffff:ffff
140fc41:8:b000::/36fc41:8:bfff:ffff:ffff:ffff:ffff:ffff
141fc41:8:c000::/36fc41:8:cfff:ffff:ffff:ffff:ffff:ffff
142fc41:8:d000::/36fc41:8:dfff:ffff:ffff:ffff:ffff:ffff
143fc41:8:e000::/36fc41:8:efff:ffff:ffff:ffff:ffff:ffff
144fc41:8:f000::/36fc41:8:ffff:ffff:ffff:ffff:ffff:ffff
145fc41:9::/36fc41:9:fff:ffff:ffff:ffff:ffff:ffff
146fc41:9:1000::/36fc41:9:1fff:ffff:ffff:ffff:ffff:ffff
147fc41:9:2000::/36fc41:9:2fff:ffff:ffff:ffff:ffff:ffff
148fc41:9:3000::/36fc41:9:3fff:ffff:ffff:ffff:ffff:ffff
149fc41:9:4000::/36fc41:9:4fff:ffff:ffff:ffff:ffff:ffff
150fc41:9:5000::/36fc41:9:5fff:ffff:ffff:ffff:ffff:ffff
151fc41:9:6000::/36fc41:9:6fff:ffff:ffff:ffff:ffff:ffff
152fc41:9:7000::/36fc41:9:7fff:ffff:ffff:ffff:ffff:ffff
153fc41:9:8000::/36fc41:9:8fff:ffff:ffff:ffff:ffff:ffff
154fc41:9:9000::/36fc41:9:9fff:ffff:ffff:ffff:ffff:ffff
155fc41:9:a000::/36fc41:9:afff:ffff:ffff:ffff:ffff:ffff
156fc41:9:b000::/36fc41:9:bfff:ffff:ffff:ffff:ffff:ffff
157fc41:9:c000::/36fc41:9:cfff:ffff:ffff:ffff:ffff:ffff
158fc41:9:d000::/36fc41:9:dfff:ffff:ffff:ffff:ffff:ffff
159fc41:9:e000::/36fc41:9:efff:ffff:ffff:ffff:ffff:ffff
160fc41:9:f000::/36fc41:9:ffff:ffff:ffff:ffff:ffff:ffff
161fc41:a::/36fc41:a:fff:ffff:ffff:ffff:ffff:ffff
162fc41:a:1000::/36fc41:a:1fff:ffff:ffff:ffff:ffff:ffff
163fc41:a:2000::/36fc41:a:2fff:ffff:ffff:ffff:ffff:ffff
164fc41:a:3000::/36fc41:a:3fff:ffff:ffff:ffff:ffff:ffff
165fc41:a:4000::/36fc41:a:4fff:ffff:ffff:ffff:ffff:ffff
166fc41:a:5000::/36fc41:a:5fff:ffff:ffff:ffff:ffff:ffff
167fc41:a:6000::/36fc41:a:6fff:ffff:ffff:ffff:ffff:ffff
168fc41:a:7000::/36fc41:a:7fff:ffff:ffff:ffff:ffff:ffff
169fc41:a:8000::/36fc41:a:8fff:ffff:ffff:ffff:ffff:ffff
170fc41:a:9000::/36fc41:a:9fff:ffff:ffff:ffff:ffff:ffff
171fc41:a:a000::/36fc41:a:afff:ffff:ffff:ffff:ffff:ffff
172fc41:a:b000::/36fc41:a:bfff:ffff:ffff:ffff:ffff:ffff
173fc41:a:c000::/36fc41:a:cfff:ffff:ffff:ffff:ffff:ffff
174fc41:a:d000::/36fc41:a:dfff:ffff:ffff:ffff:ffff:ffff
175fc41:a:e000::/36fc41:a:efff:ffff:ffff:ffff:ffff:ffff
176fc41:a:f000::/36fc41:a:ffff:ffff:ffff:ffff:ffff:ffff
177fc41:b::/36fc41:b:fff:ffff:ffff:ffff:ffff:ffff
178fc41:b:1000::/36fc41:b:1fff:ffff:ffff:ffff:ffff:ffff
179fc41:b:2000::/36fc41:b:2fff:ffff:ffff:ffff:ffff:ffff
180fc41:b:3000::/36fc41:b:3fff:ffff:ffff:ffff:ffff:ffff
181fc41:b:4000::/36fc41:b:4fff:ffff:ffff:ffff:ffff:ffff
182fc41:b:5000::/36fc41:b:5fff:ffff:ffff:ffff:ffff:ffff
183fc41:b:6000::/36fc41:b:6fff:ffff:ffff:ffff:ffff:ffff
184fc41:b:7000::/36fc41:b:7fff:ffff:ffff:ffff:ffff:ffff
185fc41:b:8000::/36fc41:b:8fff:ffff:ffff:ffff:ffff:ffff
186fc41:b:9000::/36fc41:b:9fff:ffff:ffff:ffff:ffff:ffff
187fc41:b:a000::/36fc41:b:afff:ffff:ffff:ffff:ffff:ffff
188fc41:b:b000::/36fc41:b:bfff:ffff:ffff:ffff:ffff:ffff
189fc41:b:c000::/36fc41:b:cfff:ffff:ffff:ffff:ffff:ffff
190fc41:b:d000::/36fc41:b:dfff:ffff:ffff:ffff:ffff:ffff
191fc41:b:e000::/36fc41:b:efff:ffff:ffff:ffff:ffff:ffff
192fc41:b:f000::/36fc41:b:ffff:ffff:ffff:ffff:ffff:ffff
193fc41:c::/36fc41:c:fff:ffff:ffff:ffff:ffff:ffff
194fc41:c:1000::/36fc41:c:1fff:ffff:ffff:ffff:ffff:ffff
195fc41:c:2000::/36fc41:c:2fff:ffff:ffff:ffff:ffff:ffff
196fc41:c:3000::/36fc41:c:3fff:ffff:ffff:ffff:ffff:ffff
197fc41:c:4000::/36fc41:c:4fff:ffff:ffff:ffff:ffff:ffff
198fc41:c:5000::/36fc41:c:5fff:ffff:ffff:ffff:ffff:ffff
199fc41:c:6000::/36fc41:c:6fff:ffff:ffff:ffff:ffff:ffff
200fc41:c:7000::/36fc41:c:7fff:ffff:ffff:ffff:ffff:ffff
201fc41:c:8000::/36fc41:c:8fff:ffff:ffff:ffff:ffff:ffff
202fc41:c:9000::/36fc41:c:9fff:ffff:ffff:ffff:ffff:ffff
203fc41:c:a000::/36fc41:c:afff:ffff:ffff:ffff:ffff:ffff
204fc41:c:b000::/36fc41:c:bfff:ffff:ffff:ffff:ffff:ffff
205fc41:c:c000::/36fc41:c:cfff:ffff:ffff:ffff:ffff:ffff
206fc41:c:d000::/36fc41:c:dfff:ffff:ffff:ffff:ffff:ffff
207fc41:c:e000::/36fc41:c:efff:ffff:ffff:ffff:ffff:ffff
208fc41:c:f000::/36fc41:c:ffff:ffff:ffff:ffff:ffff:ffff
209fc41:d::/36fc41:d:fff:ffff:ffff:ffff:ffff:ffff
210fc41:d:1000::/36fc41:d:1fff:ffff:ffff:ffff:ffff:ffff
211fc41:d:2000::/36fc41:d:2fff:ffff:ffff:ffff:ffff:ffff
212fc41:d:3000::/36fc41:d:3fff:ffff:ffff:ffff:ffff:ffff
213fc41:d:4000::/36fc41:d:4fff:ffff:ffff:ffff:ffff:ffff
214fc41:d:5000::/36fc41:d:5fff:ffff:ffff:ffff:ffff:ffff
215fc41:d:6000::/36fc41:d:6fff:ffff:ffff:ffff:ffff:ffff
216fc41:d:7000::/36fc41:d:7fff:ffff:ffff:ffff:ffff:ffff
217fc41:d:8000::/36fc41:d:8fff:ffff:ffff:ffff:ffff:ffff
218fc41:d:9000::/36fc41:d:9fff:ffff:ffff:ffff:ffff:ffff
219fc41:d:a000::/36fc41:d:afff:ffff:ffff:ffff:ffff:ffff
220fc41:d:b000::/36fc41:d:bfff:ffff:ffff:ffff:ffff:ffff
221fc41:d:c000::/36fc41:d:cfff:ffff:ffff:ffff:ffff:ffff
222fc41:d:d000::/36fc41:d:dfff:ffff:ffff:ffff:ffff:ffff
223fc41:d:e000::/36fc41:d:efff:ffff:ffff:ffff:ffff:ffff
224fc41:d:f000::/36fc41:d:ffff:ffff:ffff:ffff:ffff:ffff
225fc41:e::/36fc41:e:fff:ffff:ffff:ffff:ffff:ffff
226fc41:e:1000::/36fc41:e:1fff:ffff:ffff:ffff:ffff:ffff
227fc41:e:2000::/36fc41:e:2fff:ffff:ffff:ffff:ffff:ffff
228fc41:e:3000::/36fc41:e:3fff:ffff:ffff:ffff:ffff:ffff
229fc41:e:4000::/36fc41:e:4fff:ffff:ffff:ffff:ffff:ffff
230fc41:e:5000::/36fc41:e:5fff:ffff:ffff:ffff:ffff:ffff
231fc41:e:6000::/36fc41:e:6fff:ffff:ffff:ffff:ffff:ffff
232fc41:e:7000::/36fc41:e:7fff:ffff:ffff:ffff:ffff:ffff
233fc41:e:8000::/36fc41:e:8fff:ffff:ffff:ffff:ffff:ffff
234fc41:e:9000::/36fc41:e:9fff:ffff:ffff:ffff:ffff:ffff
235fc41:e:a000::/36fc41:e:afff:ffff:ffff:ffff:ffff:ffff
236fc41:e:b000::/36fc41:e:bfff:ffff:ffff:ffff:ffff:ffff
237fc41:e:c000::/36fc41:e:cfff:ffff:ffff:ffff:ffff:ffff
238fc41:e:d000::/36fc41:e:dfff:ffff:ffff:ffff:ffff:ffff
239fc41:e:e000::/36fc41:e:efff:ffff:ffff:ffff:ffff:ffff
240fc41:e:f000::/36fc41:e:ffff:ffff:ffff:ffff:ffff:ffff
241fc41:f::/36fc41:f:fff:ffff:ffff:ffff:ffff:ffff
242fc41:f:1000::/36fc41:f:1fff:ffff:ffff:ffff:ffff:ffff
243fc41:f:2000::/36fc41:f:2fff:ffff:ffff:ffff:ffff:ffff
244fc41:f:3000::/36fc41:f:3fff:ffff:ffff:ffff:ffff:ffff
245fc41:f:4000::/36fc41:f:4fff:ffff:ffff:ffff:ffff:ffff
246fc41:f:5000::/36fc41:f:5fff:ffff:ffff:ffff:ffff:ffff
247fc41:f:6000::/36fc41:f:6fff:ffff:ffff:ffff:ffff:ffff
248fc41:f:7000::/36fc41:f:7fff:ffff:ffff:ffff:ffff:ffff
249fc41:f:8000::/36fc41:f:8fff:ffff:ffff:ffff:ffff:ffff
250fc41:f:9000::/36fc41:f:9fff:ffff:ffff:ffff:ffff:ffff
251fc41:f:a000::/36fc41:f:afff:ffff:ffff:ffff:ffff:ffff
252fc41:f:b000::/36fc41:f:bfff:ffff:ffff:ffff:ffff:ffff
253fc41:f:c000::/36fc41:f:cfff:ffff:ffff:ffff:ffff:ffff
254fc41:f:d000::/36fc41:f:dfff:ffff:ffff:ffff:ffff:ffff
255fc41:f:e000::/36fc41:f:efff:ffff:ffff:ffff:ffff:ffff
256fc41:f:f000::/36fc41:f: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.