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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
fc0a:6000::/20
First address
fc0a:6000::
Last address
fc0a:6fff: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
fc0a:6000:0000:0000:0000:0000:0000:0000
Type
Unique local (ULA) fc00::/7
Private IPv6, like RFC 1918; usually fd00::/8
Reverse DNS zone
6.a.0.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)

fc0a:6000::/20 makes 65,536 subnets of /36; the first 256 are listed.

Subnets
#SubnetLast address
1fc0a:6000::/36fc0a:6000:fff:ffff:ffff:ffff:ffff:ffff
2fc0a:6000:1000::/36fc0a:6000:1fff:ffff:ffff:ffff:ffff:ffff
3fc0a:6000:2000::/36fc0a:6000:2fff:ffff:ffff:ffff:ffff:ffff
4fc0a:6000:3000::/36fc0a:6000:3fff:ffff:ffff:ffff:ffff:ffff
5fc0a:6000:4000::/36fc0a:6000:4fff:ffff:ffff:ffff:ffff:ffff
6fc0a:6000:5000::/36fc0a:6000:5fff:ffff:ffff:ffff:ffff:ffff
7fc0a:6000:6000::/36fc0a:6000:6fff:ffff:ffff:ffff:ffff:ffff
8fc0a:6000:7000::/36fc0a:6000:7fff:ffff:ffff:ffff:ffff:ffff
9fc0a:6000:8000::/36fc0a:6000:8fff:ffff:ffff:ffff:ffff:ffff
10fc0a:6000:9000::/36fc0a:6000:9fff:ffff:ffff:ffff:ffff:ffff
11fc0a:6000:a000::/36fc0a:6000:afff:ffff:ffff:ffff:ffff:ffff
12fc0a:6000:b000::/36fc0a:6000:bfff:ffff:ffff:ffff:ffff:ffff
13fc0a:6000:c000::/36fc0a:6000:cfff:ffff:ffff:ffff:ffff:ffff
14fc0a:6000:d000::/36fc0a:6000:dfff:ffff:ffff:ffff:ffff:ffff
15fc0a:6000:e000::/36fc0a:6000:efff:ffff:ffff:ffff:ffff:ffff
16fc0a:6000:f000::/36fc0a:6000:ffff:ffff:ffff:ffff:ffff:ffff
17fc0a:6001::/36fc0a:6001:fff:ffff:ffff:ffff:ffff:ffff
18fc0a:6001:1000::/36fc0a:6001:1fff:ffff:ffff:ffff:ffff:ffff
19fc0a:6001:2000::/36fc0a:6001:2fff:ffff:ffff:ffff:ffff:ffff
20fc0a:6001:3000::/36fc0a:6001:3fff:ffff:ffff:ffff:ffff:ffff
21fc0a:6001:4000::/36fc0a:6001:4fff:ffff:ffff:ffff:ffff:ffff
22fc0a:6001:5000::/36fc0a:6001:5fff:ffff:ffff:ffff:ffff:ffff
23fc0a:6001:6000::/36fc0a:6001:6fff:ffff:ffff:ffff:ffff:ffff
24fc0a:6001:7000::/36fc0a:6001:7fff:ffff:ffff:ffff:ffff:ffff
25fc0a:6001:8000::/36fc0a:6001:8fff:ffff:ffff:ffff:ffff:ffff
26fc0a:6001:9000::/36fc0a:6001:9fff:ffff:ffff:ffff:ffff:ffff
27fc0a:6001:a000::/36fc0a:6001:afff:ffff:ffff:ffff:ffff:ffff
28fc0a:6001:b000::/36fc0a:6001:bfff:ffff:ffff:ffff:ffff:ffff
29fc0a:6001:c000::/36fc0a:6001:cfff:ffff:ffff:ffff:ffff:ffff
30fc0a:6001:d000::/36fc0a:6001:dfff:ffff:ffff:ffff:ffff:ffff
31fc0a:6001:e000::/36fc0a:6001:efff:ffff:ffff:ffff:ffff:ffff
32fc0a:6001:f000::/36fc0a:6001:ffff:ffff:ffff:ffff:ffff:ffff
33fc0a:6002::/36fc0a:6002:fff:ffff:ffff:ffff:ffff:ffff
34fc0a:6002:1000::/36fc0a:6002:1fff:ffff:ffff:ffff:ffff:ffff
35fc0a:6002:2000::/36fc0a:6002:2fff:ffff:ffff:ffff:ffff:ffff
36fc0a:6002:3000::/36fc0a:6002:3fff:ffff:ffff:ffff:ffff:ffff
37fc0a:6002:4000::/36fc0a:6002:4fff:ffff:ffff:ffff:ffff:ffff
38fc0a:6002:5000::/36fc0a:6002:5fff:ffff:ffff:ffff:ffff:ffff
39fc0a:6002:6000::/36fc0a:6002:6fff:ffff:ffff:ffff:ffff:ffff
40fc0a:6002:7000::/36fc0a:6002:7fff:ffff:ffff:ffff:ffff:ffff
41fc0a:6002:8000::/36fc0a:6002:8fff:ffff:ffff:ffff:ffff:ffff
42fc0a:6002:9000::/36fc0a:6002:9fff:ffff:ffff:ffff:ffff:ffff
43fc0a:6002:a000::/36fc0a:6002:afff:ffff:ffff:ffff:ffff:ffff
44fc0a:6002:b000::/36fc0a:6002:bfff:ffff:ffff:ffff:ffff:ffff
45fc0a:6002:c000::/36fc0a:6002:cfff:ffff:ffff:ffff:ffff:ffff
46fc0a:6002:d000::/36fc0a:6002:dfff:ffff:ffff:ffff:ffff:ffff
47fc0a:6002:e000::/36fc0a:6002:efff:ffff:ffff:ffff:ffff:ffff
48fc0a:6002:f000::/36fc0a:6002:ffff:ffff:ffff:ffff:ffff:ffff
49fc0a:6003::/36fc0a:6003:fff:ffff:ffff:ffff:ffff:ffff
50fc0a:6003:1000::/36fc0a:6003:1fff:ffff:ffff:ffff:ffff:ffff
51fc0a:6003:2000::/36fc0a:6003:2fff:ffff:ffff:ffff:ffff:ffff
52fc0a:6003:3000::/36fc0a:6003:3fff:ffff:ffff:ffff:ffff:ffff
53fc0a:6003:4000::/36fc0a:6003:4fff:ffff:ffff:ffff:ffff:ffff
54fc0a:6003:5000::/36fc0a:6003:5fff:ffff:ffff:ffff:ffff:ffff
55fc0a:6003:6000::/36fc0a:6003:6fff:ffff:ffff:ffff:ffff:ffff
56fc0a:6003:7000::/36fc0a:6003:7fff:ffff:ffff:ffff:ffff:ffff
57fc0a:6003:8000::/36fc0a:6003:8fff:ffff:ffff:ffff:ffff:ffff
58fc0a:6003:9000::/36fc0a:6003:9fff:ffff:ffff:ffff:ffff:ffff
59fc0a:6003:a000::/36fc0a:6003:afff:ffff:ffff:ffff:ffff:ffff
60fc0a:6003:b000::/36fc0a:6003:bfff:ffff:ffff:ffff:ffff:ffff
61fc0a:6003:c000::/36fc0a:6003:cfff:ffff:ffff:ffff:ffff:ffff
62fc0a:6003:d000::/36fc0a:6003:dfff:ffff:ffff:ffff:ffff:ffff
63fc0a:6003:e000::/36fc0a:6003:efff:ffff:ffff:ffff:ffff:ffff
64fc0a:6003:f000::/36fc0a:6003:ffff:ffff:ffff:ffff:ffff:ffff
65fc0a:6004::/36fc0a:6004:fff:ffff:ffff:ffff:ffff:ffff
66fc0a:6004:1000::/36fc0a:6004:1fff:ffff:ffff:ffff:ffff:ffff
67fc0a:6004:2000::/36fc0a:6004:2fff:ffff:ffff:ffff:ffff:ffff
68fc0a:6004:3000::/36fc0a:6004:3fff:ffff:ffff:ffff:ffff:ffff
69fc0a:6004:4000::/36fc0a:6004:4fff:ffff:ffff:ffff:ffff:ffff
70fc0a:6004:5000::/36fc0a:6004:5fff:ffff:ffff:ffff:ffff:ffff
71fc0a:6004:6000::/36fc0a:6004:6fff:ffff:ffff:ffff:ffff:ffff
72fc0a:6004:7000::/36fc0a:6004:7fff:ffff:ffff:ffff:ffff:ffff
73fc0a:6004:8000::/36fc0a:6004:8fff:ffff:ffff:ffff:ffff:ffff
74fc0a:6004:9000::/36fc0a:6004:9fff:ffff:ffff:ffff:ffff:ffff
75fc0a:6004:a000::/36fc0a:6004:afff:ffff:ffff:ffff:ffff:ffff
76fc0a:6004:b000::/36fc0a:6004:bfff:ffff:ffff:ffff:ffff:ffff
77fc0a:6004:c000::/36fc0a:6004:cfff:ffff:ffff:ffff:ffff:ffff
78fc0a:6004:d000::/36fc0a:6004:dfff:ffff:ffff:ffff:ffff:ffff
79fc0a:6004:e000::/36fc0a:6004:efff:ffff:ffff:ffff:ffff:ffff
80fc0a:6004:f000::/36fc0a:6004:ffff:ffff:ffff:ffff:ffff:ffff
81fc0a:6005::/36fc0a:6005:fff:ffff:ffff:ffff:ffff:ffff
82fc0a:6005:1000::/36fc0a:6005:1fff:ffff:ffff:ffff:ffff:ffff
83fc0a:6005:2000::/36fc0a:6005:2fff:ffff:ffff:ffff:ffff:ffff
84fc0a:6005:3000::/36fc0a:6005:3fff:ffff:ffff:ffff:ffff:ffff
85fc0a:6005:4000::/36fc0a:6005:4fff:ffff:ffff:ffff:ffff:ffff
86fc0a:6005:5000::/36fc0a:6005:5fff:ffff:ffff:ffff:ffff:ffff
87fc0a:6005:6000::/36fc0a:6005:6fff:ffff:ffff:ffff:ffff:ffff
88fc0a:6005:7000::/36fc0a:6005:7fff:ffff:ffff:ffff:ffff:ffff
89fc0a:6005:8000::/36fc0a:6005:8fff:ffff:ffff:ffff:ffff:ffff
90fc0a:6005:9000::/36fc0a:6005:9fff:ffff:ffff:ffff:ffff:ffff
91fc0a:6005:a000::/36fc0a:6005:afff:ffff:ffff:ffff:ffff:ffff
92fc0a:6005:b000::/36fc0a:6005:bfff:ffff:ffff:ffff:ffff:ffff
93fc0a:6005:c000::/36fc0a:6005:cfff:ffff:ffff:ffff:ffff:ffff
94fc0a:6005:d000::/36fc0a:6005:dfff:ffff:ffff:ffff:ffff:ffff
95fc0a:6005:e000::/36fc0a:6005:efff:ffff:ffff:ffff:ffff:ffff
96fc0a:6005:f000::/36fc0a:6005:ffff:ffff:ffff:ffff:ffff:ffff
97fc0a:6006::/36fc0a:6006:fff:ffff:ffff:ffff:ffff:ffff
98fc0a:6006:1000::/36fc0a:6006:1fff:ffff:ffff:ffff:ffff:ffff
99fc0a:6006:2000::/36fc0a:6006:2fff:ffff:ffff:ffff:ffff:ffff
100fc0a:6006:3000::/36fc0a:6006:3fff:ffff:ffff:ffff:ffff:ffff
101fc0a:6006:4000::/36fc0a:6006:4fff:ffff:ffff:ffff:ffff:ffff
102fc0a:6006:5000::/36fc0a:6006:5fff:ffff:ffff:ffff:ffff:ffff
103fc0a:6006:6000::/36fc0a:6006:6fff:ffff:ffff:ffff:ffff:ffff
104fc0a:6006:7000::/36fc0a:6006:7fff:ffff:ffff:ffff:ffff:ffff
105fc0a:6006:8000::/36fc0a:6006:8fff:ffff:ffff:ffff:ffff:ffff
106fc0a:6006:9000::/36fc0a:6006:9fff:ffff:ffff:ffff:ffff:ffff
107fc0a:6006:a000::/36fc0a:6006:afff:ffff:ffff:ffff:ffff:ffff
108fc0a:6006:b000::/36fc0a:6006:bfff:ffff:ffff:ffff:ffff:ffff
109fc0a:6006:c000::/36fc0a:6006:cfff:ffff:ffff:ffff:ffff:ffff
110fc0a:6006:d000::/36fc0a:6006:dfff:ffff:ffff:ffff:ffff:ffff
111fc0a:6006:e000::/36fc0a:6006:efff:ffff:ffff:ffff:ffff:ffff
112fc0a:6006:f000::/36fc0a:6006:ffff:ffff:ffff:ffff:ffff:ffff
113fc0a:6007::/36fc0a:6007:fff:ffff:ffff:ffff:ffff:ffff
114fc0a:6007:1000::/36fc0a:6007:1fff:ffff:ffff:ffff:ffff:ffff
115fc0a:6007:2000::/36fc0a:6007:2fff:ffff:ffff:ffff:ffff:ffff
116fc0a:6007:3000::/36fc0a:6007:3fff:ffff:ffff:ffff:ffff:ffff
117fc0a:6007:4000::/36fc0a:6007:4fff:ffff:ffff:ffff:ffff:ffff
118fc0a:6007:5000::/36fc0a:6007:5fff:ffff:ffff:ffff:ffff:ffff
119fc0a:6007:6000::/36fc0a:6007:6fff:ffff:ffff:ffff:ffff:ffff
120fc0a:6007:7000::/36fc0a:6007:7fff:ffff:ffff:ffff:ffff:ffff
121fc0a:6007:8000::/36fc0a:6007:8fff:ffff:ffff:ffff:ffff:ffff
122fc0a:6007:9000::/36fc0a:6007:9fff:ffff:ffff:ffff:ffff:ffff
123fc0a:6007:a000::/36fc0a:6007:afff:ffff:ffff:ffff:ffff:ffff
124fc0a:6007:b000::/36fc0a:6007:bfff:ffff:ffff:ffff:ffff:ffff
125fc0a:6007:c000::/36fc0a:6007:cfff:ffff:ffff:ffff:ffff:ffff
126fc0a:6007:d000::/36fc0a:6007:dfff:ffff:ffff:ffff:ffff:ffff
127fc0a:6007:e000::/36fc0a:6007:efff:ffff:ffff:ffff:ffff:ffff
128fc0a:6007:f000::/36fc0a:6007:ffff:ffff:ffff:ffff:ffff:ffff
129fc0a:6008::/36fc0a:6008:fff:ffff:ffff:ffff:ffff:ffff
130fc0a:6008:1000::/36fc0a:6008:1fff:ffff:ffff:ffff:ffff:ffff
131fc0a:6008:2000::/36fc0a:6008:2fff:ffff:ffff:ffff:ffff:ffff
132fc0a:6008:3000::/36fc0a:6008:3fff:ffff:ffff:ffff:ffff:ffff
133fc0a:6008:4000::/36fc0a:6008:4fff:ffff:ffff:ffff:ffff:ffff
134fc0a:6008:5000::/36fc0a:6008:5fff:ffff:ffff:ffff:ffff:ffff
135fc0a:6008:6000::/36fc0a:6008:6fff:ffff:ffff:ffff:ffff:ffff
136fc0a:6008:7000::/36fc0a:6008:7fff:ffff:ffff:ffff:ffff:ffff
137fc0a:6008:8000::/36fc0a:6008:8fff:ffff:ffff:ffff:ffff:ffff
138fc0a:6008:9000::/36fc0a:6008:9fff:ffff:ffff:ffff:ffff:ffff
139fc0a:6008:a000::/36fc0a:6008:afff:ffff:ffff:ffff:ffff:ffff
140fc0a:6008:b000::/36fc0a:6008:bfff:ffff:ffff:ffff:ffff:ffff
141fc0a:6008:c000::/36fc0a:6008:cfff:ffff:ffff:ffff:ffff:ffff
142fc0a:6008:d000::/36fc0a:6008:dfff:ffff:ffff:ffff:ffff:ffff
143fc0a:6008:e000::/36fc0a:6008:efff:ffff:ffff:ffff:ffff:ffff
144fc0a:6008:f000::/36fc0a:6008:ffff:ffff:ffff:ffff:ffff:ffff
145fc0a:6009::/36fc0a:6009:fff:ffff:ffff:ffff:ffff:ffff
146fc0a:6009:1000::/36fc0a:6009:1fff:ffff:ffff:ffff:ffff:ffff
147fc0a:6009:2000::/36fc0a:6009:2fff:ffff:ffff:ffff:ffff:ffff
148fc0a:6009:3000::/36fc0a:6009:3fff:ffff:ffff:ffff:ffff:ffff
149fc0a:6009:4000::/36fc0a:6009:4fff:ffff:ffff:ffff:ffff:ffff
150fc0a:6009:5000::/36fc0a:6009:5fff:ffff:ffff:ffff:ffff:ffff
151fc0a:6009:6000::/36fc0a:6009:6fff:ffff:ffff:ffff:ffff:ffff
152fc0a:6009:7000::/36fc0a:6009:7fff:ffff:ffff:ffff:ffff:ffff
153fc0a:6009:8000::/36fc0a:6009:8fff:ffff:ffff:ffff:ffff:ffff
154fc0a:6009:9000::/36fc0a:6009:9fff:ffff:ffff:ffff:ffff:ffff
155fc0a:6009:a000::/36fc0a:6009:afff:ffff:ffff:ffff:ffff:ffff
156fc0a:6009:b000::/36fc0a:6009:bfff:ffff:ffff:ffff:ffff:ffff
157fc0a:6009:c000::/36fc0a:6009:cfff:ffff:ffff:ffff:ffff:ffff
158fc0a:6009:d000::/36fc0a:6009:dfff:ffff:ffff:ffff:ffff:ffff
159fc0a:6009:e000::/36fc0a:6009:efff:ffff:ffff:ffff:ffff:ffff
160fc0a:6009:f000::/36fc0a:6009:ffff:ffff:ffff:ffff:ffff:ffff
161fc0a:600a::/36fc0a:600a:fff:ffff:ffff:ffff:ffff:ffff
162fc0a:600a:1000::/36fc0a:600a:1fff:ffff:ffff:ffff:ffff:ffff
163fc0a:600a:2000::/36fc0a:600a:2fff:ffff:ffff:ffff:ffff:ffff
164fc0a:600a:3000::/36fc0a:600a:3fff:ffff:ffff:ffff:ffff:ffff
165fc0a:600a:4000::/36fc0a:600a:4fff:ffff:ffff:ffff:ffff:ffff
166fc0a:600a:5000::/36fc0a:600a:5fff:ffff:ffff:ffff:ffff:ffff
167fc0a:600a:6000::/36fc0a:600a:6fff:ffff:ffff:ffff:ffff:ffff
168fc0a:600a:7000::/36fc0a:600a:7fff:ffff:ffff:ffff:ffff:ffff
169fc0a:600a:8000::/36fc0a:600a:8fff:ffff:ffff:ffff:ffff:ffff
170fc0a:600a:9000::/36fc0a:600a:9fff:ffff:ffff:ffff:ffff:ffff
171fc0a:600a:a000::/36fc0a:600a:afff:ffff:ffff:ffff:ffff:ffff
172fc0a:600a:b000::/36fc0a:600a:bfff:ffff:ffff:ffff:ffff:ffff
173fc0a:600a:c000::/36fc0a:600a:cfff:ffff:ffff:ffff:ffff:ffff
174fc0a:600a:d000::/36fc0a:600a:dfff:ffff:ffff:ffff:ffff:ffff
175fc0a:600a:e000::/36fc0a:600a:efff:ffff:ffff:ffff:ffff:ffff
176fc0a:600a:f000::/36fc0a:600a:ffff:ffff:ffff:ffff:ffff:ffff
177fc0a:600b::/36fc0a:600b:fff:ffff:ffff:ffff:ffff:ffff
178fc0a:600b:1000::/36fc0a:600b:1fff:ffff:ffff:ffff:ffff:ffff
179fc0a:600b:2000::/36fc0a:600b:2fff:ffff:ffff:ffff:ffff:ffff
180fc0a:600b:3000::/36fc0a:600b:3fff:ffff:ffff:ffff:ffff:ffff
181fc0a:600b:4000::/36fc0a:600b:4fff:ffff:ffff:ffff:ffff:ffff
182fc0a:600b:5000::/36fc0a:600b:5fff:ffff:ffff:ffff:ffff:ffff
183fc0a:600b:6000::/36fc0a:600b:6fff:ffff:ffff:ffff:ffff:ffff
184fc0a:600b:7000::/36fc0a:600b:7fff:ffff:ffff:ffff:ffff:ffff
185fc0a:600b:8000::/36fc0a:600b:8fff:ffff:ffff:ffff:ffff:ffff
186fc0a:600b:9000::/36fc0a:600b:9fff:ffff:ffff:ffff:ffff:ffff
187fc0a:600b:a000::/36fc0a:600b:afff:ffff:ffff:ffff:ffff:ffff
188fc0a:600b:b000::/36fc0a:600b:bfff:ffff:ffff:ffff:ffff:ffff
189fc0a:600b:c000::/36fc0a:600b:cfff:ffff:ffff:ffff:ffff:ffff
190fc0a:600b:d000::/36fc0a:600b:dfff:ffff:ffff:ffff:ffff:ffff
191fc0a:600b:e000::/36fc0a:600b:efff:ffff:ffff:ffff:ffff:ffff
192fc0a:600b:f000::/36fc0a:600b:ffff:ffff:ffff:ffff:ffff:ffff
193fc0a:600c::/36fc0a:600c:fff:ffff:ffff:ffff:ffff:ffff
194fc0a:600c:1000::/36fc0a:600c:1fff:ffff:ffff:ffff:ffff:ffff
195fc0a:600c:2000::/36fc0a:600c:2fff:ffff:ffff:ffff:ffff:ffff
196fc0a:600c:3000::/36fc0a:600c:3fff:ffff:ffff:ffff:ffff:ffff
197fc0a:600c:4000::/36fc0a:600c:4fff:ffff:ffff:ffff:ffff:ffff
198fc0a:600c:5000::/36fc0a:600c:5fff:ffff:ffff:ffff:ffff:ffff
199fc0a:600c:6000::/36fc0a:600c:6fff:ffff:ffff:ffff:ffff:ffff
200fc0a:600c:7000::/36fc0a:600c:7fff:ffff:ffff:ffff:ffff:ffff
201fc0a:600c:8000::/36fc0a:600c:8fff:ffff:ffff:ffff:ffff:ffff
202fc0a:600c:9000::/36fc0a:600c:9fff:ffff:ffff:ffff:ffff:ffff
203fc0a:600c:a000::/36fc0a:600c:afff:ffff:ffff:ffff:ffff:ffff
204fc0a:600c:b000::/36fc0a:600c:bfff:ffff:ffff:ffff:ffff:ffff
205fc0a:600c:c000::/36fc0a:600c:cfff:ffff:ffff:ffff:ffff:ffff
206fc0a:600c:d000::/36fc0a:600c:dfff:ffff:ffff:ffff:ffff:ffff
207fc0a:600c:e000::/36fc0a:600c:efff:ffff:ffff:ffff:ffff:ffff
208fc0a:600c:f000::/36fc0a:600c:ffff:ffff:ffff:ffff:ffff:ffff
209fc0a:600d::/36fc0a:600d:fff:ffff:ffff:ffff:ffff:ffff
210fc0a:600d:1000::/36fc0a:600d:1fff:ffff:ffff:ffff:ffff:ffff
211fc0a:600d:2000::/36fc0a:600d:2fff:ffff:ffff:ffff:ffff:ffff
212fc0a:600d:3000::/36fc0a:600d:3fff:ffff:ffff:ffff:ffff:ffff
213fc0a:600d:4000::/36fc0a:600d:4fff:ffff:ffff:ffff:ffff:ffff
214fc0a:600d:5000::/36fc0a:600d:5fff:ffff:ffff:ffff:ffff:ffff
215fc0a:600d:6000::/36fc0a:600d:6fff:ffff:ffff:ffff:ffff:ffff
216fc0a:600d:7000::/36fc0a:600d:7fff:ffff:ffff:ffff:ffff:ffff
217fc0a:600d:8000::/36fc0a:600d:8fff:ffff:ffff:ffff:ffff:ffff
218fc0a:600d:9000::/36fc0a:600d:9fff:ffff:ffff:ffff:ffff:ffff
219fc0a:600d:a000::/36fc0a:600d:afff:ffff:ffff:ffff:ffff:ffff
220fc0a:600d:b000::/36fc0a:600d:bfff:ffff:ffff:ffff:ffff:ffff
221fc0a:600d:c000::/36fc0a:600d:cfff:ffff:ffff:ffff:ffff:ffff
222fc0a:600d:d000::/36fc0a:600d:dfff:ffff:ffff:ffff:ffff:ffff
223fc0a:600d:e000::/36fc0a:600d:efff:ffff:ffff:ffff:ffff:ffff
224fc0a:600d:f000::/36fc0a:600d:ffff:ffff:ffff:ffff:ffff:ffff
225fc0a:600e::/36fc0a:600e:fff:ffff:ffff:ffff:ffff:ffff
226fc0a:600e:1000::/36fc0a:600e:1fff:ffff:ffff:ffff:ffff:ffff
227fc0a:600e:2000::/36fc0a:600e:2fff:ffff:ffff:ffff:ffff:ffff
228fc0a:600e:3000::/36fc0a:600e:3fff:ffff:ffff:ffff:ffff:ffff
229fc0a:600e:4000::/36fc0a:600e:4fff:ffff:ffff:ffff:ffff:ffff
230fc0a:600e:5000::/36fc0a:600e:5fff:ffff:ffff:ffff:ffff:ffff
231fc0a:600e:6000::/36fc0a:600e:6fff:ffff:ffff:ffff:ffff:ffff
232fc0a:600e:7000::/36fc0a:600e:7fff:ffff:ffff:ffff:ffff:ffff
233fc0a:600e:8000::/36fc0a:600e:8fff:ffff:ffff:ffff:ffff:ffff
234fc0a:600e:9000::/36fc0a:600e:9fff:ffff:ffff:ffff:ffff:ffff
235fc0a:600e:a000::/36fc0a:600e:afff:ffff:ffff:ffff:ffff:ffff
236fc0a:600e:b000::/36fc0a:600e:bfff:ffff:ffff:ffff:ffff:ffff
237fc0a:600e:c000::/36fc0a:600e:cfff:ffff:ffff:ffff:ffff:ffff
238fc0a:600e:d000::/36fc0a:600e:dfff:ffff:ffff:ffff:ffff:ffff
239fc0a:600e:e000::/36fc0a:600e:efff:ffff:ffff:ffff:ffff:ffff
240fc0a:600e:f000::/36fc0a:600e:ffff:ffff:ffff:ffff:ffff:ffff
241fc0a:600f::/36fc0a:600f:fff:ffff:ffff:ffff:ffff:ffff
242fc0a:600f:1000::/36fc0a:600f:1fff:ffff:ffff:ffff:ffff:ffff
243fc0a:600f:2000::/36fc0a:600f:2fff:ffff:ffff:ffff:ffff:ffff
244fc0a:600f:3000::/36fc0a:600f:3fff:ffff:ffff:ffff:ffff:ffff
245fc0a:600f:4000::/36fc0a:600f:4fff:ffff:ffff:ffff:ffff:ffff
246fc0a:600f:5000::/36fc0a:600f:5fff:ffff:ffff:ffff:ffff:ffff
247fc0a:600f:6000::/36fc0a:600f:6fff:ffff:ffff:ffff:ffff:ffff
248fc0a:600f:7000::/36fc0a:600f:7fff:ffff:ffff:ffff:ffff:ffff
249fc0a:600f:8000::/36fc0a:600f:8fff:ffff:ffff:ffff:ffff:ffff
250fc0a:600f:9000::/36fc0a:600f:9fff:ffff:ffff:ffff:ffff:ffff
251fc0a:600f:a000::/36fc0a:600f:afff:ffff:ffff:ffff:ffff:ffff
252fc0a:600f:b000::/36fc0a:600f:bfff:ffff:ffff:ffff:ffff:ffff
253fc0a:600f:c000::/36fc0a:600f:cfff:ffff:ffff:ffff:ffff:ffff
254fc0a:600f:d000::/36fc0a:600f:dfff:ffff:ffff:ffff:ffff:ffff
255fc0a:600f:e000::/36fc0a:600f:efff:ffff:ffff:ffff:ffff:ffff
256fc0a:600f:f000::/36fc0a:600f: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.