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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/11
Addresses2^117
/64 networks2^53
Network
fc40::/11
First address
fc40::
Last address
fc5f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
Addresses
166,153,499,473,114,484,112,975,882,535,043,072 (2^117)
/64 networks (LANs)
9,007,199,254,740,992 (2^53)
Full form
fc40:0000:0000:0000:0000:0000:0000:0000
Type
Unique local (ULA) fc00::/7
Private IPv6, like RFC 1918; usually fd00::/8
Reverse DNS zones
4.c.f.ip6.arpa
5.c.f.ip6.arpa
/11 is not on a 4-bit boundary, so it takes 2 /12 zones.
Split into smaller subnets/20
/12 (2)/13 (4)/14 (8)/15 (16)/16 (32)/20 (512)/24 (8,192)

fc40::/11 makes 512 subnets of /20; the first 256 are listed.

Subnets
#SubnetLast address
1fc40::/20fc40:fff:ffff:ffff:ffff:ffff:ffff:ffff
2fc40:1000::/20fc40:1fff:ffff:ffff:ffff:ffff:ffff:ffff
3fc40:2000::/20fc40:2fff:ffff:ffff:ffff:ffff:ffff:ffff
4fc40:3000::/20fc40:3fff:ffff:ffff:ffff:ffff:ffff:ffff
5fc40:4000::/20fc40:4fff:ffff:ffff:ffff:ffff:ffff:ffff
6fc40:5000::/20fc40:5fff:ffff:ffff:ffff:ffff:ffff:ffff
7fc40:6000::/20fc40:6fff:ffff:ffff:ffff:ffff:ffff:ffff
8fc40:7000::/20fc40:7fff:ffff:ffff:ffff:ffff:ffff:ffff
9fc40:8000::/20fc40:8fff:ffff:ffff:ffff:ffff:ffff:ffff
10fc40:9000::/20fc40:9fff:ffff:ffff:ffff:ffff:ffff:ffff
11fc40:a000::/20fc40:afff:ffff:ffff:ffff:ffff:ffff:ffff
12fc40:b000::/20fc40:bfff:ffff:ffff:ffff:ffff:ffff:ffff
13fc40:c000::/20fc40:cfff:ffff:ffff:ffff:ffff:ffff:ffff
14fc40:d000::/20fc40:dfff:ffff:ffff:ffff:ffff:ffff:ffff
15fc40:e000::/20fc40:efff:ffff:ffff:ffff:ffff:ffff:ffff
16fc40:f000::/20fc40:ffff:ffff:ffff:ffff:ffff:ffff:ffff
17fc41::/20fc41:fff:ffff:ffff:ffff:ffff:ffff:ffff
18fc41:1000::/20fc41:1fff:ffff:ffff:ffff:ffff:ffff:ffff
19fc41:2000::/20fc41:2fff:ffff:ffff:ffff:ffff:ffff:ffff
20fc41:3000::/20fc41:3fff:ffff:ffff:ffff:ffff:ffff:ffff
21fc41:4000::/20fc41:4fff:ffff:ffff:ffff:ffff:ffff:ffff
22fc41:5000::/20fc41:5fff:ffff:ffff:ffff:ffff:ffff:ffff
23fc41:6000::/20fc41:6fff:ffff:ffff:ffff:ffff:ffff:ffff
24fc41:7000::/20fc41:7fff:ffff:ffff:ffff:ffff:ffff:ffff
25fc41:8000::/20fc41:8fff:ffff:ffff:ffff:ffff:ffff:ffff
26fc41:9000::/20fc41:9fff:ffff:ffff:ffff:ffff:ffff:ffff
27fc41:a000::/20fc41:afff:ffff:ffff:ffff:ffff:ffff:ffff
28fc41:b000::/20fc41:bfff:ffff:ffff:ffff:ffff:ffff:ffff
29fc41:c000::/20fc41:cfff:ffff:ffff:ffff:ffff:ffff:ffff
30fc41:d000::/20fc41:dfff:ffff:ffff:ffff:ffff:ffff:ffff
31fc41:e000::/20fc41:efff:ffff:ffff:ffff:ffff:ffff:ffff
32fc41:f000::/20fc41:ffff:ffff:ffff:ffff:ffff:ffff:ffff
33fc42::/20fc42:fff:ffff:ffff:ffff:ffff:ffff:ffff
34fc42:1000::/20fc42:1fff:ffff:ffff:ffff:ffff:ffff:ffff
35fc42:2000::/20fc42:2fff:ffff:ffff:ffff:ffff:ffff:ffff
36fc42:3000::/20fc42:3fff:ffff:ffff:ffff:ffff:ffff:ffff
37fc42:4000::/20fc42:4fff:ffff:ffff:ffff:ffff:ffff:ffff
38fc42:5000::/20fc42:5fff:ffff:ffff:ffff:ffff:ffff:ffff
39fc42:6000::/20fc42:6fff:ffff:ffff:ffff:ffff:ffff:ffff
40fc42:7000::/20fc42:7fff:ffff:ffff:ffff:ffff:ffff:ffff
41fc42:8000::/20fc42:8fff:ffff:ffff:ffff:ffff:ffff:ffff
42fc42:9000::/20fc42:9fff:ffff:ffff:ffff:ffff:ffff:ffff
43fc42:a000::/20fc42:afff:ffff:ffff:ffff:ffff:ffff:ffff
44fc42:b000::/20fc42:bfff:ffff:ffff:ffff:ffff:ffff:ffff
45fc42:c000::/20fc42:cfff:ffff:ffff:ffff:ffff:ffff:ffff
46fc42:d000::/20fc42:dfff:ffff:ffff:ffff:ffff:ffff:ffff
47fc42:e000::/20fc42:efff:ffff:ffff:ffff:ffff:ffff:ffff
48fc42:f000::/20fc42:ffff:ffff:ffff:ffff:ffff:ffff:ffff
49fc43::/20fc43:fff:ffff:ffff:ffff:ffff:ffff:ffff
50fc43:1000::/20fc43:1fff:ffff:ffff:ffff:ffff:ffff:ffff
51fc43:2000::/20fc43:2fff:ffff:ffff:ffff:ffff:ffff:ffff
52fc43:3000::/20fc43:3fff:ffff:ffff:ffff:ffff:ffff:ffff
53fc43:4000::/20fc43:4fff:ffff:ffff:ffff:ffff:ffff:ffff
54fc43:5000::/20fc43:5fff:ffff:ffff:ffff:ffff:ffff:ffff
55fc43:6000::/20fc43:6fff:ffff:ffff:ffff:ffff:ffff:ffff
56fc43:7000::/20fc43:7fff:ffff:ffff:ffff:ffff:ffff:ffff
57fc43:8000::/20fc43:8fff:ffff:ffff:ffff:ffff:ffff:ffff
58fc43:9000::/20fc43:9fff:ffff:ffff:ffff:ffff:ffff:ffff
59fc43:a000::/20fc43:afff:ffff:ffff:ffff:ffff:ffff:ffff
60fc43:b000::/20fc43:bfff:ffff:ffff:ffff:ffff:ffff:ffff
61fc43:c000::/20fc43:cfff:ffff:ffff:ffff:ffff:ffff:ffff
62fc43:d000::/20fc43:dfff:ffff:ffff:ffff:ffff:ffff:ffff
63fc43:e000::/20fc43:efff:ffff:ffff:ffff:ffff:ffff:ffff
64fc43:f000::/20fc43:ffff:ffff:ffff:ffff:ffff:ffff:ffff
65fc44::/20fc44:fff:ffff:ffff:ffff:ffff:ffff:ffff
66fc44:1000::/20fc44:1fff:ffff:ffff:ffff:ffff:ffff:ffff
67fc44:2000::/20fc44:2fff:ffff:ffff:ffff:ffff:ffff:ffff
68fc44:3000::/20fc44:3fff:ffff:ffff:ffff:ffff:ffff:ffff
69fc44:4000::/20fc44:4fff:ffff:ffff:ffff:ffff:ffff:ffff
70fc44:5000::/20fc44:5fff:ffff:ffff:ffff:ffff:ffff:ffff
71fc44:6000::/20fc44:6fff:ffff:ffff:ffff:ffff:ffff:ffff
72fc44:7000::/20fc44:7fff:ffff:ffff:ffff:ffff:ffff:ffff
73fc44:8000::/20fc44:8fff:ffff:ffff:ffff:ffff:ffff:ffff
74fc44:9000::/20fc44:9fff:ffff:ffff:ffff:ffff:ffff:ffff
75fc44:a000::/20fc44:afff:ffff:ffff:ffff:ffff:ffff:ffff
76fc44:b000::/20fc44:bfff:ffff:ffff:ffff:ffff:ffff:ffff
77fc44:c000::/20fc44:cfff:ffff:ffff:ffff:ffff:ffff:ffff
78fc44:d000::/20fc44:dfff:ffff:ffff:ffff:ffff:ffff:ffff
79fc44:e000::/20fc44:efff:ffff:ffff:ffff:ffff:ffff:ffff
80fc44:f000::/20fc44:ffff:ffff:ffff:ffff:ffff:ffff:ffff
81fc45::/20fc45:fff:ffff:ffff:ffff:ffff:ffff:ffff
82fc45:1000::/20fc45:1fff:ffff:ffff:ffff:ffff:ffff:ffff
83fc45:2000::/20fc45:2fff:ffff:ffff:ffff:ffff:ffff:ffff
84fc45:3000::/20fc45:3fff:ffff:ffff:ffff:ffff:ffff:ffff
85fc45:4000::/20fc45:4fff:ffff:ffff:ffff:ffff:ffff:ffff
86fc45:5000::/20fc45:5fff:ffff:ffff:ffff:ffff:ffff:ffff
87fc45:6000::/20fc45:6fff:ffff:ffff:ffff:ffff:ffff:ffff
88fc45:7000::/20fc45:7fff:ffff:ffff:ffff:ffff:ffff:ffff
89fc45:8000::/20fc45:8fff:ffff:ffff:ffff:ffff:ffff:ffff
90fc45:9000::/20fc45:9fff:ffff:ffff:ffff:ffff:ffff:ffff
91fc45:a000::/20fc45:afff:ffff:ffff:ffff:ffff:ffff:ffff
92fc45:b000::/20fc45:bfff:ffff:ffff:ffff:ffff:ffff:ffff
93fc45:c000::/20fc45:cfff:ffff:ffff:ffff:ffff:ffff:ffff
94fc45:d000::/20fc45:dfff:ffff:ffff:ffff:ffff:ffff:ffff
95fc45:e000::/20fc45:efff:ffff:ffff:ffff:ffff:ffff:ffff
96fc45:f000::/20fc45:ffff:ffff:ffff:ffff:ffff:ffff:ffff
97fc46::/20fc46:fff:ffff:ffff:ffff:ffff:ffff:ffff
98fc46:1000::/20fc46:1fff:ffff:ffff:ffff:ffff:ffff:ffff
99fc46:2000::/20fc46:2fff:ffff:ffff:ffff:ffff:ffff:ffff
100fc46:3000::/20fc46:3fff:ffff:ffff:ffff:ffff:ffff:ffff
101fc46:4000::/20fc46:4fff:ffff:ffff:ffff:ffff:ffff:ffff
102fc46:5000::/20fc46:5fff:ffff:ffff:ffff:ffff:ffff:ffff
103fc46:6000::/20fc46:6fff:ffff:ffff:ffff:ffff:ffff:ffff
104fc46:7000::/20fc46:7fff:ffff:ffff:ffff:ffff:ffff:ffff
105fc46:8000::/20fc46:8fff:ffff:ffff:ffff:ffff:ffff:ffff
106fc46:9000::/20fc46:9fff:ffff:ffff:ffff:ffff:ffff:ffff
107fc46:a000::/20fc46:afff:ffff:ffff:ffff:ffff:ffff:ffff
108fc46:b000::/20fc46:bfff:ffff:ffff:ffff:ffff:ffff:ffff
109fc46:c000::/20fc46:cfff:ffff:ffff:ffff:ffff:ffff:ffff
110fc46:d000::/20fc46:dfff:ffff:ffff:ffff:ffff:ffff:ffff
111fc46:e000::/20fc46:efff:ffff:ffff:ffff:ffff:ffff:ffff
112fc46:f000::/20fc46:ffff:ffff:ffff:ffff:ffff:ffff:ffff
113fc47::/20fc47:fff:ffff:ffff:ffff:ffff:ffff:ffff
114fc47:1000::/20fc47:1fff:ffff:ffff:ffff:ffff:ffff:ffff
115fc47:2000::/20fc47:2fff:ffff:ffff:ffff:ffff:ffff:ffff
116fc47:3000::/20fc47:3fff:ffff:ffff:ffff:ffff:ffff:ffff
117fc47:4000::/20fc47:4fff:ffff:ffff:ffff:ffff:ffff:ffff
118fc47:5000::/20fc47:5fff:ffff:ffff:ffff:ffff:ffff:ffff
119fc47:6000::/20fc47:6fff:ffff:ffff:ffff:ffff:ffff:ffff
120fc47:7000::/20fc47:7fff:ffff:ffff:ffff:ffff:ffff:ffff
121fc47:8000::/20fc47:8fff:ffff:ffff:ffff:ffff:ffff:ffff
122fc47:9000::/20fc47:9fff:ffff:ffff:ffff:ffff:ffff:ffff
123fc47:a000::/20fc47:afff:ffff:ffff:ffff:ffff:ffff:ffff
124fc47:b000::/20fc47:bfff:ffff:ffff:ffff:ffff:ffff:ffff
125fc47:c000::/20fc47:cfff:ffff:ffff:ffff:ffff:ffff:ffff
126fc47:d000::/20fc47:dfff:ffff:ffff:ffff:ffff:ffff:ffff
127fc47:e000::/20fc47:efff:ffff:ffff:ffff:ffff:ffff:ffff
128fc47:f000::/20fc47:ffff:ffff:ffff:ffff:ffff:ffff:ffff
129fc48::/20fc48:fff:ffff:ffff:ffff:ffff:ffff:ffff
130fc48:1000::/20fc48:1fff:ffff:ffff:ffff:ffff:ffff:ffff
131fc48:2000::/20fc48:2fff:ffff:ffff:ffff:ffff:ffff:ffff
132fc48:3000::/20fc48:3fff:ffff:ffff:ffff:ffff:ffff:ffff
133fc48:4000::/20fc48:4fff:ffff:ffff:ffff:ffff:ffff:ffff
134fc48:5000::/20fc48:5fff:ffff:ffff:ffff:ffff:ffff:ffff
135fc48:6000::/20fc48:6fff:ffff:ffff:ffff:ffff:ffff:ffff
136fc48:7000::/20fc48:7fff:ffff:ffff:ffff:ffff:ffff:ffff
137fc48:8000::/20fc48:8fff:ffff:ffff:ffff:ffff:ffff:ffff
138fc48:9000::/20fc48:9fff:ffff:ffff:ffff:ffff:ffff:ffff
139fc48:a000::/20fc48:afff:ffff:ffff:ffff:ffff:ffff:ffff
140fc48:b000::/20fc48:bfff:ffff:ffff:ffff:ffff:ffff:ffff
141fc48:c000::/20fc48:cfff:ffff:ffff:ffff:ffff:ffff:ffff
142fc48:d000::/20fc48:dfff:ffff:ffff:ffff:ffff:ffff:ffff
143fc48:e000::/20fc48:efff:ffff:ffff:ffff:ffff:ffff:ffff
144fc48:f000::/20fc48:ffff:ffff:ffff:ffff:ffff:ffff:ffff
145fc49::/20fc49:fff:ffff:ffff:ffff:ffff:ffff:ffff
146fc49:1000::/20fc49:1fff:ffff:ffff:ffff:ffff:ffff:ffff
147fc49:2000::/20fc49:2fff:ffff:ffff:ffff:ffff:ffff:ffff
148fc49:3000::/20fc49:3fff:ffff:ffff:ffff:ffff:ffff:ffff
149fc49:4000::/20fc49:4fff:ffff:ffff:ffff:ffff:ffff:ffff
150fc49:5000::/20fc49:5fff:ffff:ffff:ffff:ffff:ffff:ffff
151fc49:6000::/20fc49:6fff:ffff:ffff:ffff:ffff:ffff:ffff
152fc49:7000::/20fc49:7fff:ffff:ffff:ffff:ffff:ffff:ffff
153fc49:8000::/20fc49:8fff:ffff:ffff:ffff:ffff:ffff:ffff
154fc49:9000::/20fc49:9fff:ffff:ffff:ffff:ffff:ffff:ffff
155fc49:a000::/20fc49:afff:ffff:ffff:ffff:ffff:ffff:ffff
156fc49:b000::/20fc49:bfff:ffff:ffff:ffff:ffff:ffff:ffff
157fc49:c000::/20fc49:cfff:ffff:ffff:ffff:ffff:ffff:ffff
158fc49:d000::/20fc49:dfff:ffff:ffff:ffff:ffff:ffff:ffff
159fc49:e000::/20fc49:efff:ffff:ffff:ffff:ffff:ffff:ffff
160fc49:f000::/20fc49:ffff:ffff:ffff:ffff:ffff:ffff:ffff
161fc4a::/20fc4a:fff:ffff:ffff:ffff:ffff:ffff:ffff
162fc4a:1000::/20fc4a:1fff:ffff:ffff:ffff:ffff:ffff:ffff
163fc4a:2000::/20fc4a:2fff:ffff:ffff:ffff:ffff:ffff:ffff
164fc4a:3000::/20fc4a:3fff:ffff:ffff:ffff:ffff:ffff:ffff
165fc4a:4000::/20fc4a:4fff:ffff:ffff:ffff:ffff:ffff:ffff
166fc4a:5000::/20fc4a:5fff:ffff:ffff:ffff:ffff:ffff:ffff
167fc4a:6000::/20fc4a:6fff:ffff:ffff:ffff:ffff:ffff:ffff
168fc4a:7000::/20fc4a:7fff:ffff:ffff:ffff:ffff:ffff:ffff
169fc4a:8000::/20fc4a:8fff:ffff:ffff:ffff:ffff:ffff:ffff
170fc4a:9000::/20fc4a:9fff:ffff:ffff:ffff:ffff:ffff:ffff
171fc4a:a000::/20fc4a:afff:ffff:ffff:ffff:ffff:ffff:ffff
172fc4a:b000::/20fc4a:bfff:ffff:ffff:ffff:ffff:ffff:ffff
173fc4a:c000::/20fc4a:cfff:ffff:ffff:ffff:ffff:ffff:ffff
174fc4a:d000::/20fc4a:dfff:ffff:ffff:ffff:ffff:ffff:ffff
175fc4a:e000::/20fc4a:efff:ffff:ffff:ffff:ffff:ffff:ffff
176fc4a:f000::/20fc4a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
177fc4b::/20fc4b:fff:ffff:ffff:ffff:ffff:ffff:ffff
178fc4b:1000::/20fc4b:1fff:ffff:ffff:ffff:ffff:ffff:ffff
179fc4b:2000::/20fc4b:2fff:ffff:ffff:ffff:ffff:ffff:ffff
180fc4b:3000::/20fc4b:3fff:ffff:ffff:ffff:ffff:ffff:ffff
181fc4b:4000::/20fc4b:4fff:ffff:ffff:ffff:ffff:ffff:ffff
182fc4b:5000::/20fc4b:5fff:ffff:ffff:ffff:ffff:ffff:ffff
183fc4b:6000::/20fc4b:6fff:ffff:ffff:ffff:ffff:ffff:ffff
184fc4b:7000::/20fc4b:7fff:ffff:ffff:ffff:ffff:ffff:ffff
185fc4b:8000::/20fc4b:8fff:ffff:ffff:ffff:ffff:ffff:ffff
186fc4b:9000::/20fc4b:9fff:ffff:ffff:ffff:ffff:ffff:ffff
187fc4b:a000::/20fc4b:afff:ffff:ffff:ffff:ffff:ffff:ffff
188fc4b:b000::/20fc4b:bfff:ffff:ffff:ffff:ffff:ffff:ffff
189fc4b:c000::/20fc4b:cfff:ffff:ffff:ffff:ffff:ffff:ffff
190fc4b:d000::/20fc4b:dfff:ffff:ffff:ffff:ffff:ffff:ffff
191fc4b:e000::/20fc4b:efff:ffff:ffff:ffff:ffff:ffff:ffff
192fc4b:f000::/20fc4b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
193fc4c::/20fc4c:fff:ffff:ffff:ffff:ffff:ffff:ffff
194fc4c:1000::/20fc4c:1fff:ffff:ffff:ffff:ffff:ffff:ffff
195fc4c:2000::/20fc4c:2fff:ffff:ffff:ffff:ffff:ffff:ffff
196fc4c:3000::/20fc4c:3fff:ffff:ffff:ffff:ffff:ffff:ffff
197fc4c:4000::/20fc4c:4fff:ffff:ffff:ffff:ffff:ffff:ffff
198fc4c:5000::/20fc4c:5fff:ffff:ffff:ffff:ffff:ffff:ffff
199fc4c:6000::/20fc4c:6fff:ffff:ffff:ffff:ffff:ffff:ffff
200fc4c:7000::/20fc4c:7fff:ffff:ffff:ffff:ffff:ffff:ffff
201fc4c:8000::/20fc4c:8fff:ffff:ffff:ffff:ffff:ffff:ffff
202fc4c:9000::/20fc4c:9fff:ffff:ffff:ffff:ffff:ffff:ffff
203fc4c:a000::/20fc4c:afff:ffff:ffff:ffff:ffff:ffff:ffff
204fc4c:b000::/20fc4c:bfff:ffff:ffff:ffff:ffff:ffff:ffff
205fc4c:c000::/20fc4c:cfff:ffff:ffff:ffff:ffff:ffff:ffff
206fc4c:d000::/20fc4c:dfff:ffff:ffff:ffff:ffff:ffff:ffff
207fc4c:e000::/20fc4c:efff:ffff:ffff:ffff:ffff:ffff:ffff
208fc4c:f000::/20fc4c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
209fc4d::/20fc4d:fff:ffff:ffff:ffff:ffff:ffff:ffff
210fc4d:1000::/20fc4d:1fff:ffff:ffff:ffff:ffff:ffff:ffff
211fc4d:2000::/20fc4d:2fff:ffff:ffff:ffff:ffff:ffff:ffff
212fc4d:3000::/20fc4d:3fff:ffff:ffff:ffff:ffff:ffff:ffff
213fc4d:4000::/20fc4d:4fff:ffff:ffff:ffff:ffff:ffff:ffff
214fc4d:5000::/20fc4d:5fff:ffff:ffff:ffff:ffff:ffff:ffff
215fc4d:6000::/20fc4d:6fff:ffff:ffff:ffff:ffff:ffff:ffff
216fc4d:7000::/20fc4d:7fff:ffff:ffff:ffff:ffff:ffff:ffff
217fc4d:8000::/20fc4d:8fff:ffff:ffff:ffff:ffff:ffff:ffff
218fc4d:9000::/20fc4d:9fff:ffff:ffff:ffff:ffff:ffff:ffff
219fc4d:a000::/20fc4d:afff:ffff:ffff:ffff:ffff:ffff:ffff
220fc4d:b000::/20fc4d:bfff:ffff:ffff:ffff:ffff:ffff:ffff
221fc4d:c000::/20fc4d:cfff:ffff:ffff:ffff:ffff:ffff:ffff
222fc4d:d000::/20fc4d:dfff:ffff:ffff:ffff:ffff:ffff:ffff
223fc4d:e000::/20fc4d:efff:ffff:ffff:ffff:ffff:ffff:ffff
224fc4d:f000::/20fc4d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
225fc4e::/20fc4e:fff:ffff:ffff:ffff:ffff:ffff:ffff
226fc4e:1000::/20fc4e:1fff:ffff:ffff:ffff:ffff:ffff:ffff
227fc4e:2000::/20fc4e:2fff:ffff:ffff:ffff:ffff:ffff:ffff
228fc4e:3000::/20fc4e:3fff:ffff:ffff:ffff:ffff:ffff:ffff
229fc4e:4000::/20fc4e:4fff:ffff:ffff:ffff:ffff:ffff:ffff
230fc4e:5000::/20fc4e:5fff:ffff:ffff:ffff:ffff:ffff:ffff
231fc4e:6000::/20fc4e:6fff:ffff:ffff:ffff:ffff:ffff:ffff
232fc4e:7000::/20fc4e:7fff:ffff:ffff:ffff:ffff:ffff:ffff
233fc4e:8000::/20fc4e:8fff:ffff:ffff:ffff:ffff:ffff:ffff
234fc4e:9000::/20fc4e:9fff:ffff:ffff:ffff:ffff:ffff:ffff
235fc4e:a000::/20fc4e:afff:ffff:ffff:ffff:ffff:ffff:ffff
236fc4e:b000::/20fc4e:bfff:ffff:ffff:ffff:ffff:ffff:ffff
237fc4e:c000::/20fc4e:cfff:ffff:ffff:ffff:ffff:ffff:ffff
238fc4e:d000::/20fc4e:dfff:ffff:ffff:ffff:ffff:ffff:ffff
239fc4e:e000::/20fc4e:efff:ffff:ffff:ffff:ffff:ffff:ffff
240fc4e:f000::/20fc4e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
241fc4f::/20fc4f:fff:ffff:ffff:ffff:ffff:ffff:ffff
242fc4f:1000::/20fc4f:1fff:ffff:ffff:ffff:ffff:ffff:ffff
243fc4f:2000::/20fc4f:2fff:ffff:ffff:ffff:ffff:ffff:ffff
244fc4f:3000::/20fc4f:3fff:ffff:ffff:ffff:ffff:ffff:ffff
245fc4f:4000::/20fc4f:4fff:ffff:ffff:ffff:ffff:ffff:ffff
246fc4f:5000::/20fc4f:5fff:ffff:ffff:ffff:ffff:ffff:ffff
247fc4f:6000::/20fc4f:6fff:ffff:ffff:ffff:ffff:ffff:ffff
248fc4f:7000::/20fc4f:7fff:ffff:ffff:ffff:ffff:ffff:ffff
249fc4f:8000::/20fc4f:8fff:ffff:ffff:ffff:ffff:ffff:ffff
250fc4f:9000::/20fc4f:9fff:ffff:ffff:ffff:ffff:ffff:ffff
251fc4f:a000::/20fc4f:afff:ffff:ffff:ffff:ffff:ffff:ffff
252fc4f:b000::/20fc4f:bfff:ffff:ffff:ffff:ffff:ffff:ffff
253fc4f:c000::/20fc4f:cfff:ffff:ffff:ffff:ffff:ffff:ffff
254fc4f:d000::/20fc4f:dfff:ffff:ffff:ffff:ffff:ffff:ffff
255fc4f:e000::/20fc4f:efff:ffff:ffff:ffff:ffff:ffff:ffff
256fc4f:f000::/20fc4f:ffff: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.