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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/10
Addresses2^118
/64 networks2^54
Network
ffc0::/10
First address
ffc0::
Last address
ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff
Addresses
332,306,998,946,228,968,225,951,765,070,086,144 (2^118)
/64 networks (LANs)
18,014,398,509,481,984 (2^54)
Full form
ffc0:0000:0000:0000:0000:0000:0000:0000
Type
Multicast ff00::/8
One-to-many traffic; replaces broadcast
Reverse DNS zones
c.f.f.ip6.arpa
d.f.f.ip6.arpa
e.f.f.ip6.arpa
f.f.f.ip6.arpa
/10 is not on a 4-bit boundary, so it takes 4 /12 zones.
Split into smaller subnets/20
/11 (2)/12 (4)/13 (8)/14 (16)/16 (64)/20 (1,024)/24 (16,384)

ffc0::/10 makes 1,024 subnets of /20; the first 256 are listed.

Subnets
#SubnetLast address
1ffc0::/20ffc0:fff:ffff:ffff:ffff:ffff:ffff:ffff
2ffc0:1000::/20ffc0:1fff:ffff:ffff:ffff:ffff:ffff:ffff
3ffc0:2000::/20ffc0:2fff:ffff:ffff:ffff:ffff:ffff:ffff
4ffc0:3000::/20ffc0:3fff:ffff:ffff:ffff:ffff:ffff:ffff
5ffc0:4000::/20ffc0:4fff:ffff:ffff:ffff:ffff:ffff:ffff
6ffc0:5000::/20ffc0:5fff:ffff:ffff:ffff:ffff:ffff:ffff
7ffc0:6000::/20ffc0:6fff:ffff:ffff:ffff:ffff:ffff:ffff
8ffc0:7000::/20ffc0:7fff:ffff:ffff:ffff:ffff:ffff:ffff
9ffc0:8000::/20ffc0:8fff:ffff:ffff:ffff:ffff:ffff:ffff
10ffc0:9000::/20ffc0:9fff:ffff:ffff:ffff:ffff:ffff:ffff
11ffc0:a000::/20ffc0:afff:ffff:ffff:ffff:ffff:ffff:ffff
12ffc0:b000::/20ffc0:bfff:ffff:ffff:ffff:ffff:ffff:ffff
13ffc0:c000::/20ffc0:cfff:ffff:ffff:ffff:ffff:ffff:ffff
14ffc0:d000::/20ffc0:dfff:ffff:ffff:ffff:ffff:ffff:ffff
15ffc0:e000::/20ffc0:efff:ffff:ffff:ffff:ffff:ffff:ffff
16ffc0:f000::/20ffc0:ffff:ffff:ffff:ffff:ffff:ffff:ffff
17ffc1::/20ffc1:fff:ffff:ffff:ffff:ffff:ffff:ffff
18ffc1:1000::/20ffc1:1fff:ffff:ffff:ffff:ffff:ffff:ffff
19ffc1:2000::/20ffc1:2fff:ffff:ffff:ffff:ffff:ffff:ffff
20ffc1:3000::/20ffc1:3fff:ffff:ffff:ffff:ffff:ffff:ffff
21ffc1:4000::/20ffc1:4fff:ffff:ffff:ffff:ffff:ffff:ffff
22ffc1:5000::/20ffc1:5fff:ffff:ffff:ffff:ffff:ffff:ffff
23ffc1:6000::/20ffc1:6fff:ffff:ffff:ffff:ffff:ffff:ffff
24ffc1:7000::/20ffc1:7fff:ffff:ffff:ffff:ffff:ffff:ffff
25ffc1:8000::/20ffc1:8fff:ffff:ffff:ffff:ffff:ffff:ffff
26ffc1:9000::/20ffc1:9fff:ffff:ffff:ffff:ffff:ffff:ffff
27ffc1:a000::/20ffc1:afff:ffff:ffff:ffff:ffff:ffff:ffff
28ffc1:b000::/20ffc1:bfff:ffff:ffff:ffff:ffff:ffff:ffff
29ffc1:c000::/20ffc1:cfff:ffff:ffff:ffff:ffff:ffff:ffff
30ffc1:d000::/20ffc1:dfff:ffff:ffff:ffff:ffff:ffff:ffff
31ffc1:e000::/20ffc1:efff:ffff:ffff:ffff:ffff:ffff:ffff
32ffc1:f000::/20ffc1:ffff:ffff:ffff:ffff:ffff:ffff:ffff
33ffc2::/20ffc2:fff:ffff:ffff:ffff:ffff:ffff:ffff
34ffc2:1000::/20ffc2:1fff:ffff:ffff:ffff:ffff:ffff:ffff
35ffc2:2000::/20ffc2:2fff:ffff:ffff:ffff:ffff:ffff:ffff
36ffc2:3000::/20ffc2:3fff:ffff:ffff:ffff:ffff:ffff:ffff
37ffc2:4000::/20ffc2:4fff:ffff:ffff:ffff:ffff:ffff:ffff
38ffc2:5000::/20ffc2:5fff:ffff:ffff:ffff:ffff:ffff:ffff
39ffc2:6000::/20ffc2:6fff:ffff:ffff:ffff:ffff:ffff:ffff
40ffc2:7000::/20ffc2:7fff:ffff:ffff:ffff:ffff:ffff:ffff
41ffc2:8000::/20ffc2:8fff:ffff:ffff:ffff:ffff:ffff:ffff
42ffc2:9000::/20ffc2:9fff:ffff:ffff:ffff:ffff:ffff:ffff
43ffc2:a000::/20ffc2:afff:ffff:ffff:ffff:ffff:ffff:ffff
44ffc2:b000::/20ffc2:bfff:ffff:ffff:ffff:ffff:ffff:ffff
45ffc2:c000::/20ffc2:cfff:ffff:ffff:ffff:ffff:ffff:ffff
46ffc2:d000::/20ffc2:dfff:ffff:ffff:ffff:ffff:ffff:ffff
47ffc2:e000::/20ffc2:efff:ffff:ffff:ffff:ffff:ffff:ffff
48ffc2:f000::/20ffc2:ffff:ffff:ffff:ffff:ffff:ffff:ffff
49ffc3::/20ffc3:fff:ffff:ffff:ffff:ffff:ffff:ffff
50ffc3:1000::/20ffc3:1fff:ffff:ffff:ffff:ffff:ffff:ffff
51ffc3:2000::/20ffc3:2fff:ffff:ffff:ffff:ffff:ffff:ffff
52ffc3:3000::/20ffc3:3fff:ffff:ffff:ffff:ffff:ffff:ffff
53ffc3:4000::/20ffc3:4fff:ffff:ffff:ffff:ffff:ffff:ffff
54ffc3:5000::/20ffc3:5fff:ffff:ffff:ffff:ffff:ffff:ffff
55ffc3:6000::/20ffc3:6fff:ffff:ffff:ffff:ffff:ffff:ffff
56ffc3:7000::/20ffc3:7fff:ffff:ffff:ffff:ffff:ffff:ffff
57ffc3:8000::/20ffc3:8fff:ffff:ffff:ffff:ffff:ffff:ffff
58ffc3:9000::/20ffc3:9fff:ffff:ffff:ffff:ffff:ffff:ffff
59ffc3:a000::/20ffc3:afff:ffff:ffff:ffff:ffff:ffff:ffff
60ffc3:b000::/20ffc3:bfff:ffff:ffff:ffff:ffff:ffff:ffff
61ffc3:c000::/20ffc3:cfff:ffff:ffff:ffff:ffff:ffff:ffff
62ffc3:d000::/20ffc3:dfff:ffff:ffff:ffff:ffff:ffff:ffff
63ffc3:e000::/20ffc3:efff:ffff:ffff:ffff:ffff:ffff:ffff
64ffc3:f000::/20ffc3:ffff:ffff:ffff:ffff:ffff:ffff:ffff
65ffc4::/20ffc4:fff:ffff:ffff:ffff:ffff:ffff:ffff
66ffc4:1000::/20ffc4:1fff:ffff:ffff:ffff:ffff:ffff:ffff
67ffc4:2000::/20ffc4:2fff:ffff:ffff:ffff:ffff:ffff:ffff
68ffc4:3000::/20ffc4:3fff:ffff:ffff:ffff:ffff:ffff:ffff
69ffc4:4000::/20ffc4:4fff:ffff:ffff:ffff:ffff:ffff:ffff
70ffc4:5000::/20ffc4:5fff:ffff:ffff:ffff:ffff:ffff:ffff
71ffc4:6000::/20ffc4:6fff:ffff:ffff:ffff:ffff:ffff:ffff
72ffc4:7000::/20ffc4:7fff:ffff:ffff:ffff:ffff:ffff:ffff
73ffc4:8000::/20ffc4:8fff:ffff:ffff:ffff:ffff:ffff:ffff
74ffc4:9000::/20ffc4:9fff:ffff:ffff:ffff:ffff:ffff:ffff
75ffc4:a000::/20ffc4:afff:ffff:ffff:ffff:ffff:ffff:ffff
76ffc4:b000::/20ffc4:bfff:ffff:ffff:ffff:ffff:ffff:ffff
77ffc4:c000::/20ffc4:cfff:ffff:ffff:ffff:ffff:ffff:ffff
78ffc4:d000::/20ffc4:dfff:ffff:ffff:ffff:ffff:ffff:ffff
79ffc4:e000::/20ffc4:efff:ffff:ffff:ffff:ffff:ffff:ffff
80ffc4:f000::/20ffc4:ffff:ffff:ffff:ffff:ffff:ffff:ffff
81ffc5::/20ffc5:fff:ffff:ffff:ffff:ffff:ffff:ffff
82ffc5:1000::/20ffc5:1fff:ffff:ffff:ffff:ffff:ffff:ffff
83ffc5:2000::/20ffc5:2fff:ffff:ffff:ffff:ffff:ffff:ffff
84ffc5:3000::/20ffc5:3fff:ffff:ffff:ffff:ffff:ffff:ffff
85ffc5:4000::/20ffc5:4fff:ffff:ffff:ffff:ffff:ffff:ffff
86ffc5:5000::/20ffc5:5fff:ffff:ffff:ffff:ffff:ffff:ffff
87ffc5:6000::/20ffc5:6fff:ffff:ffff:ffff:ffff:ffff:ffff
88ffc5:7000::/20ffc5:7fff:ffff:ffff:ffff:ffff:ffff:ffff
89ffc5:8000::/20ffc5:8fff:ffff:ffff:ffff:ffff:ffff:ffff
90ffc5:9000::/20ffc5:9fff:ffff:ffff:ffff:ffff:ffff:ffff
91ffc5:a000::/20ffc5:afff:ffff:ffff:ffff:ffff:ffff:ffff
92ffc5:b000::/20ffc5:bfff:ffff:ffff:ffff:ffff:ffff:ffff
93ffc5:c000::/20ffc5:cfff:ffff:ffff:ffff:ffff:ffff:ffff
94ffc5:d000::/20ffc5:dfff:ffff:ffff:ffff:ffff:ffff:ffff
95ffc5:e000::/20ffc5:efff:ffff:ffff:ffff:ffff:ffff:ffff
96ffc5:f000::/20ffc5:ffff:ffff:ffff:ffff:ffff:ffff:ffff
97ffc6::/20ffc6:fff:ffff:ffff:ffff:ffff:ffff:ffff
98ffc6:1000::/20ffc6:1fff:ffff:ffff:ffff:ffff:ffff:ffff
99ffc6:2000::/20ffc6:2fff:ffff:ffff:ffff:ffff:ffff:ffff
100ffc6:3000::/20ffc6:3fff:ffff:ffff:ffff:ffff:ffff:ffff
101ffc6:4000::/20ffc6:4fff:ffff:ffff:ffff:ffff:ffff:ffff
102ffc6:5000::/20ffc6:5fff:ffff:ffff:ffff:ffff:ffff:ffff
103ffc6:6000::/20ffc6:6fff:ffff:ffff:ffff:ffff:ffff:ffff
104ffc6:7000::/20ffc6:7fff:ffff:ffff:ffff:ffff:ffff:ffff
105ffc6:8000::/20ffc6:8fff:ffff:ffff:ffff:ffff:ffff:ffff
106ffc6:9000::/20ffc6:9fff:ffff:ffff:ffff:ffff:ffff:ffff
107ffc6:a000::/20ffc6:afff:ffff:ffff:ffff:ffff:ffff:ffff
108ffc6:b000::/20ffc6:bfff:ffff:ffff:ffff:ffff:ffff:ffff
109ffc6:c000::/20ffc6:cfff:ffff:ffff:ffff:ffff:ffff:ffff
110ffc6:d000::/20ffc6:dfff:ffff:ffff:ffff:ffff:ffff:ffff
111ffc6:e000::/20ffc6:efff:ffff:ffff:ffff:ffff:ffff:ffff
112ffc6:f000::/20ffc6:ffff:ffff:ffff:ffff:ffff:ffff:ffff
113ffc7::/20ffc7:fff:ffff:ffff:ffff:ffff:ffff:ffff
114ffc7:1000::/20ffc7:1fff:ffff:ffff:ffff:ffff:ffff:ffff
115ffc7:2000::/20ffc7:2fff:ffff:ffff:ffff:ffff:ffff:ffff
116ffc7:3000::/20ffc7:3fff:ffff:ffff:ffff:ffff:ffff:ffff
117ffc7:4000::/20ffc7:4fff:ffff:ffff:ffff:ffff:ffff:ffff
118ffc7:5000::/20ffc7:5fff:ffff:ffff:ffff:ffff:ffff:ffff
119ffc7:6000::/20ffc7:6fff:ffff:ffff:ffff:ffff:ffff:ffff
120ffc7:7000::/20ffc7:7fff:ffff:ffff:ffff:ffff:ffff:ffff
121ffc7:8000::/20ffc7:8fff:ffff:ffff:ffff:ffff:ffff:ffff
122ffc7:9000::/20ffc7:9fff:ffff:ffff:ffff:ffff:ffff:ffff
123ffc7:a000::/20ffc7:afff:ffff:ffff:ffff:ffff:ffff:ffff
124ffc7:b000::/20ffc7:bfff:ffff:ffff:ffff:ffff:ffff:ffff
125ffc7:c000::/20ffc7:cfff:ffff:ffff:ffff:ffff:ffff:ffff
126ffc7:d000::/20ffc7:dfff:ffff:ffff:ffff:ffff:ffff:ffff
127ffc7:e000::/20ffc7:efff:ffff:ffff:ffff:ffff:ffff:ffff
128ffc7:f000::/20ffc7:ffff:ffff:ffff:ffff:ffff:ffff:ffff
129ffc8::/20ffc8:fff:ffff:ffff:ffff:ffff:ffff:ffff
130ffc8:1000::/20ffc8:1fff:ffff:ffff:ffff:ffff:ffff:ffff
131ffc8:2000::/20ffc8:2fff:ffff:ffff:ffff:ffff:ffff:ffff
132ffc8:3000::/20ffc8:3fff:ffff:ffff:ffff:ffff:ffff:ffff
133ffc8:4000::/20ffc8:4fff:ffff:ffff:ffff:ffff:ffff:ffff
134ffc8:5000::/20ffc8:5fff:ffff:ffff:ffff:ffff:ffff:ffff
135ffc8:6000::/20ffc8:6fff:ffff:ffff:ffff:ffff:ffff:ffff
136ffc8:7000::/20ffc8:7fff:ffff:ffff:ffff:ffff:ffff:ffff
137ffc8:8000::/20ffc8:8fff:ffff:ffff:ffff:ffff:ffff:ffff
138ffc8:9000::/20ffc8:9fff:ffff:ffff:ffff:ffff:ffff:ffff
139ffc8:a000::/20ffc8:afff:ffff:ffff:ffff:ffff:ffff:ffff
140ffc8:b000::/20ffc8:bfff:ffff:ffff:ffff:ffff:ffff:ffff
141ffc8:c000::/20ffc8:cfff:ffff:ffff:ffff:ffff:ffff:ffff
142ffc8:d000::/20ffc8:dfff:ffff:ffff:ffff:ffff:ffff:ffff
143ffc8:e000::/20ffc8:efff:ffff:ffff:ffff:ffff:ffff:ffff
144ffc8:f000::/20ffc8:ffff:ffff:ffff:ffff:ffff:ffff:ffff
145ffc9::/20ffc9:fff:ffff:ffff:ffff:ffff:ffff:ffff
146ffc9:1000::/20ffc9:1fff:ffff:ffff:ffff:ffff:ffff:ffff
147ffc9:2000::/20ffc9:2fff:ffff:ffff:ffff:ffff:ffff:ffff
148ffc9:3000::/20ffc9:3fff:ffff:ffff:ffff:ffff:ffff:ffff
149ffc9:4000::/20ffc9:4fff:ffff:ffff:ffff:ffff:ffff:ffff
150ffc9:5000::/20ffc9:5fff:ffff:ffff:ffff:ffff:ffff:ffff
151ffc9:6000::/20ffc9:6fff:ffff:ffff:ffff:ffff:ffff:ffff
152ffc9:7000::/20ffc9:7fff:ffff:ffff:ffff:ffff:ffff:ffff
153ffc9:8000::/20ffc9:8fff:ffff:ffff:ffff:ffff:ffff:ffff
154ffc9:9000::/20ffc9:9fff:ffff:ffff:ffff:ffff:ffff:ffff
155ffc9:a000::/20ffc9:afff:ffff:ffff:ffff:ffff:ffff:ffff
156ffc9:b000::/20ffc9:bfff:ffff:ffff:ffff:ffff:ffff:ffff
157ffc9:c000::/20ffc9:cfff:ffff:ffff:ffff:ffff:ffff:ffff
158ffc9:d000::/20ffc9:dfff:ffff:ffff:ffff:ffff:ffff:ffff
159ffc9:e000::/20ffc9:efff:ffff:ffff:ffff:ffff:ffff:ffff
160ffc9:f000::/20ffc9:ffff:ffff:ffff:ffff:ffff:ffff:ffff
161ffca::/20ffca:fff:ffff:ffff:ffff:ffff:ffff:ffff
162ffca:1000::/20ffca:1fff:ffff:ffff:ffff:ffff:ffff:ffff
163ffca:2000::/20ffca:2fff:ffff:ffff:ffff:ffff:ffff:ffff
164ffca:3000::/20ffca:3fff:ffff:ffff:ffff:ffff:ffff:ffff
165ffca:4000::/20ffca:4fff:ffff:ffff:ffff:ffff:ffff:ffff
166ffca:5000::/20ffca:5fff:ffff:ffff:ffff:ffff:ffff:ffff
167ffca:6000::/20ffca:6fff:ffff:ffff:ffff:ffff:ffff:ffff
168ffca:7000::/20ffca:7fff:ffff:ffff:ffff:ffff:ffff:ffff
169ffca:8000::/20ffca:8fff:ffff:ffff:ffff:ffff:ffff:ffff
170ffca:9000::/20ffca:9fff:ffff:ffff:ffff:ffff:ffff:ffff
171ffca:a000::/20ffca:afff:ffff:ffff:ffff:ffff:ffff:ffff
172ffca:b000::/20ffca:bfff:ffff:ffff:ffff:ffff:ffff:ffff
173ffca:c000::/20ffca:cfff:ffff:ffff:ffff:ffff:ffff:ffff
174ffca:d000::/20ffca:dfff:ffff:ffff:ffff:ffff:ffff:ffff
175ffca:e000::/20ffca:efff:ffff:ffff:ffff:ffff:ffff:ffff
176ffca:f000::/20ffca:ffff:ffff:ffff:ffff:ffff:ffff:ffff
177ffcb::/20ffcb:fff:ffff:ffff:ffff:ffff:ffff:ffff
178ffcb:1000::/20ffcb:1fff:ffff:ffff:ffff:ffff:ffff:ffff
179ffcb:2000::/20ffcb:2fff:ffff:ffff:ffff:ffff:ffff:ffff
180ffcb:3000::/20ffcb:3fff:ffff:ffff:ffff:ffff:ffff:ffff
181ffcb:4000::/20ffcb:4fff:ffff:ffff:ffff:ffff:ffff:ffff
182ffcb:5000::/20ffcb:5fff:ffff:ffff:ffff:ffff:ffff:ffff
183ffcb:6000::/20ffcb:6fff:ffff:ffff:ffff:ffff:ffff:ffff
184ffcb:7000::/20ffcb:7fff:ffff:ffff:ffff:ffff:ffff:ffff
185ffcb:8000::/20ffcb:8fff:ffff:ffff:ffff:ffff:ffff:ffff
186ffcb:9000::/20ffcb:9fff:ffff:ffff:ffff:ffff:ffff:ffff
187ffcb:a000::/20ffcb:afff:ffff:ffff:ffff:ffff:ffff:ffff
188ffcb:b000::/20ffcb:bfff:ffff:ffff:ffff:ffff:ffff:ffff
189ffcb:c000::/20ffcb:cfff:ffff:ffff:ffff:ffff:ffff:ffff
190ffcb:d000::/20ffcb:dfff:ffff:ffff:ffff:ffff:ffff:ffff
191ffcb:e000::/20ffcb:efff:ffff:ffff:ffff:ffff:ffff:ffff
192ffcb:f000::/20ffcb:ffff:ffff:ffff:ffff:ffff:ffff:ffff
193ffcc::/20ffcc:fff:ffff:ffff:ffff:ffff:ffff:ffff
194ffcc:1000::/20ffcc:1fff:ffff:ffff:ffff:ffff:ffff:ffff
195ffcc:2000::/20ffcc:2fff:ffff:ffff:ffff:ffff:ffff:ffff
196ffcc:3000::/20ffcc:3fff:ffff:ffff:ffff:ffff:ffff:ffff
197ffcc:4000::/20ffcc:4fff:ffff:ffff:ffff:ffff:ffff:ffff
198ffcc:5000::/20ffcc:5fff:ffff:ffff:ffff:ffff:ffff:ffff
199ffcc:6000::/20ffcc:6fff:ffff:ffff:ffff:ffff:ffff:ffff
200ffcc:7000::/20ffcc:7fff:ffff:ffff:ffff:ffff:ffff:ffff
201ffcc:8000::/20ffcc:8fff:ffff:ffff:ffff:ffff:ffff:ffff
202ffcc:9000::/20ffcc:9fff:ffff:ffff:ffff:ffff:ffff:ffff
203ffcc:a000::/20ffcc:afff:ffff:ffff:ffff:ffff:ffff:ffff
204ffcc:b000::/20ffcc:bfff:ffff:ffff:ffff:ffff:ffff:ffff
205ffcc:c000::/20ffcc:cfff:ffff:ffff:ffff:ffff:ffff:ffff
206ffcc:d000::/20ffcc:dfff:ffff:ffff:ffff:ffff:ffff:ffff
207ffcc:e000::/20ffcc:efff:ffff:ffff:ffff:ffff:ffff:ffff
208ffcc:f000::/20ffcc:ffff:ffff:ffff:ffff:ffff:ffff:ffff
209ffcd::/20ffcd:fff:ffff:ffff:ffff:ffff:ffff:ffff
210ffcd:1000::/20ffcd:1fff:ffff:ffff:ffff:ffff:ffff:ffff
211ffcd:2000::/20ffcd:2fff:ffff:ffff:ffff:ffff:ffff:ffff
212ffcd:3000::/20ffcd:3fff:ffff:ffff:ffff:ffff:ffff:ffff
213ffcd:4000::/20ffcd:4fff:ffff:ffff:ffff:ffff:ffff:ffff
214ffcd:5000::/20ffcd:5fff:ffff:ffff:ffff:ffff:ffff:ffff
215ffcd:6000::/20ffcd:6fff:ffff:ffff:ffff:ffff:ffff:ffff
216ffcd:7000::/20ffcd:7fff:ffff:ffff:ffff:ffff:ffff:ffff
217ffcd:8000::/20ffcd:8fff:ffff:ffff:ffff:ffff:ffff:ffff
218ffcd:9000::/20ffcd:9fff:ffff:ffff:ffff:ffff:ffff:ffff
219ffcd:a000::/20ffcd:afff:ffff:ffff:ffff:ffff:ffff:ffff
220ffcd:b000::/20ffcd:bfff:ffff:ffff:ffff:ffff:ffff:ffff
221ffcd:c000::/20ffcd:cfff:ffff:ffff:ffff:ffff:ffff:ffff
222ffcd:d000::/20ffcd:dfff:ffff:ffff:ffff:ffff:ffff:ffff
223ffcd:e000::/20ffcd:efff:ffff:ffff:ffff:ffff:ffff:ffff
224ffcd:f000::/20ffcd:ffff:ffff:ffff:ffff:ffff:ffff:ffff
225ffce::/20ffce:fff:ffff:ffff:ffff:ffff:ffff:ffff
226ffce:1000::/20ffce:1fff:ffff:ffff:ffff:ffff:ffff:ffff
227ffce:2000::/20ffce:2fff:ffff:ffff:ffff:ffff:ffff:ffff
228ffce:3000::/20ffce:3fff:ffff:ffff:ffff:ffff:ffff:ffff
229ffce:4000::/20ffce:4fff:ffff:ffff:ffff:ffff:ffff:ffff
230ffce:5000::/20ffce:5fff:ffff:ffff:ffff:ffff:ffff:ffff
231ffce:6000::/20ffce:6fff:ffff:ffff:ffff:ffff:ffff:ffff
232ffce:7000::/20ffce:7fff:ffff:ffff:ffff:ffff:ffff:ffff
233ffce:8000::/20ffce:8fff:ffff:ffff:ffff:ffff:ffff:ffff
234ffce:9000::/20ffce:9fff:ffff:ffff:ffff:ffff:ffff:ffff
235ffce:a000::/20ffce:afff:ffff:ffff:ffff:ffff:ffff:ffff
236ffce:b000::/20ffce:bfff:ffff:ffff:ffff:ffff:ffff:ffff
237ffce:c000::/20ffce:cfff:ffff:ffff:ffff:ffff:ffff:ffff
238ffce:d000::/20ffce:dfff:ffff:ffff:ffff:ffff:ffff:ffff
239ffce:e000::/20ffce:efff:ffff:ffff:ffff:ffff:ffff:ffff
240ffce:f000::/20ffce:ffff:ffff:ffff:ffff:ffff:ffff:ffff
241ffcf::/20ffcf:fff:ffff:ffff:ffff:ffff:ffff:ffff
242ffcf:1000::/20ffcf:1fff:ffff:ffff:ffff:ffff:ffff:ffff
243ffcf:2000::/20ffcf:2fff:ffff:ffff:ffff:ffff:ffff:ffff
244ffcf:3000::/20ffcf:3fff:ffff:ffff:ffff:ffff:ffff:ffff
245ffcf:4000::/20ffcf:4fff:ffff:ffff:ffff:ffff:ffff:ffff
246ffcf:5000::/20ffcf:5fff:ffff:ffff:ffff:ffff:ffff:ffff
247ffcf:6000::/20ffcf:6fff:ffff:ffff:ffff:ffff:ffff:ffff
248ffcf:7000::/20ffcf:7fff:ffff:ffff:ffff:ffff:ffff:ffff
249ffcf:8000::/20ffcf:8fff:ffff:ffff:ffff:ffff:ffff:ffff
250ffcf:9000::/20ffcf:9fff:ffff:ffff:ffff:ffff:ffff:ffff
251ffcf:a000::/20ffcf:afff:ffff:ffff:ffff:ffff:ffff:ffff
252ffcf:b000::/20ffcf:bfff:ffff:ffff:ffff:ffff:ffff:ffff
253ffcf:c000::/20ffcf:cfff:ffff:ffff:ffff:ffff:ffff:ffff
254ffcf:d000::/20ffcf:dfff:ffff:ffff:ffff:ffff:ffff:ffff
255ffcf:e000::/20ffcf:efff:ffff:ffff:ffff:ffff:ffff:ffff
256ffcf:f000::/20ffcf: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.