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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
fffd::/16
First address
fffd::
Last address
fffd: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
fffd:0000:0000:0000:0000:0000:0000:0000
Type
Multicast ff00::/8
One-to-many traffic; replaces broadcast
Reverse DNS zone
d.f.f.f.ip6.arpa
Split into smaller subnets/24
/17 (2)/18 (4)/19 (8)/20 (16)/24 (256)/28 (4,096)/32 (65,536)

fffd::/16 makes 256 subnets of /24.

Subnets
#SubnetLast address
1fffd::/24fffd:ff:ffff:ffff:ffff:ffff:ffff:ffff
2fffd:100::/24fffd:1ff:ffff:ffff:ffff:ffff:ffff:ffff
3fffd:200::/24fffd:2ff:ffff:ffff:ffff:ffff:ffff:ffff
4fffd:300::/24fffd:3ff:ffff:ffff:ffff:ffff:ffff:ffff
5fffd:400::/24fffd:4ff:ffff:ffff:ffff:ffff:ffff:ffff
6fffd:500::/24fffd:5ff:ffff:ffff:ffff:ffff:ffff:ffff
7fffd:600::/24fffd:6ff:ffff:ffff:ffff:ffff:ffff:ffff
8fffd:700::/24fffd:7ff:ffff:ffff:ffff:ffff:ffff:ffff
9fffd:800::/24fffd:8ff:ffff:ffff:ffff:ffff:ffff:ffff
10fffd:900::/24fffd:9ff:ffff:ffff:ffff:ffff:ffff:ffff
11fffd:a00::/24fffd:aff:ffff:ffff:ffff:ffff:ffff:ffff
12fffd:b00::/24fffd:bff:ffff:ffff:ffff:ffff:ffff:ffff
13fffd:c00::/24fffd:cff:ffff:ffff:ffff:ffff:ffff:ffff
14fffd:d00::/24fffd:dff:ffff:ffff:ffff:ffff:ffff:ffff
15fffd:e00::/24fffd:eff:ffff:ffff:ffff:ffff:ffff:ffff
16fffd:f00::/24fffd:fff:ffff:ffff:ffff:ffff:ffff:ffff
17fffd:1000::/24fffd:10ff:ffff:ffff:ffff:ffff:ffff:ffff
18fffd:1100::/24fffd:11ff:ffff:ffff:ffff:ffff:ffff:ffff
19fffd:1200::/24fffd:12ff:ffff:ffff:ffff:ffff:ffff:ffff
20fffd:1300::/24fffd:13ff:ffff:ffff:ffff:ffff:ffff:ffff
21fffd:1400::/24fffd:14ff:ffff:ffff:ffff:ffff:ffff:ffff
22fffd:1500::/24fffd:15ff:ffff:ffff:ffff:ffff:ffff:ffff
23fffd:1600::/24fffd:16ff:ffff:ffff:ffff:ffff:ffff:ffff
24fffd:1700::/24fffd:17ff:ffff:ffff:ffff:ffff:ffff:ffff
25fffd:1800::/24fffd:18ff:ffff:ffff:ffff:ffff:ffff:ffff
26fffd:1900::/24fffd:19ff:ffff:ffff:ffff:ffff:ffff:ffff
27fffd:1a00::/24fffd:1aff:ffff:ffff:ffff:ffff:ffff:ffff
28fffd:1b00::/24fffd:1bff:ffff:ffff:ffff:ffff:ffff:ffff
29fffd:1c00::/24fffd:1cff:ffff:ffff:ffff:ffff:ffff:ffff
30fffd:1d00::/24fffd:1dff:ffff:ffff:ffff:ffff:ffff:ffff
31fffd:1e00::/24fffd:1eff:ffff:ffff:ffff:ffff:ffff:ffff
32fffd:1f00::/24fffd:1fff:ffff:ffff:ffff:ffff:ffff:ffff
33fffd:2000::/24fffd:20ff:ffff:ffff:ffff:ffff:ffff:ffff
34fffd:2100::/24fffd:21ff:ffff:ffff:ffff:ffff:ffff:ffff
35fffd:2200::/24fffd:22ff:ffff:ffff:ffff:ffff:ffff:ffff
36fffd:2300::/24fffd:23ff:ffff:ffff:ffff:ffff:ffff:ffff
37fffd:2400::/24fffd:24ff:ffff:ffff:ffff:ffff:ffff:ffff
38fffd:2500::/24fffd:25ff:ffff:ffff:ffff:ffff:ffff:ffff
39fffd:2600::/24fffd:26ff:ffff:ffff:ffff:ffff:ffff:ffff
40fffd:2700::/24fffd:27ff:ffff:ffff:ffff:ffff:ffff:ffff
41fffd:2800::/24fffd:28ff:ffff:ffff:ffff:ffff:ffff:ffff
42fffd:2900::/24fffd:29ff:ffff:ffff:ffff:ffff:ffff:ffff
43fffd:2a00::/24fffd:2aff:ffff:ffff:ffff:ffff:ffff:ffff
44fffd:2b00::/24fffd:2bff:ffff:ffff:ffff:ffff:ffff:ffff
45fffd:2c00::/24fffd:2cff:ffff:ffff:ffff:ffff:ffff:ffff
46fffd:2d00::/24fffd:2dff:ffff:ffff:ffff:ffff:ffff:ffff
47fffd:2e00::/24fffd:2eff:ffff:ffff:ffff:ffff:ffff:ffff
48fffd:2f00::/24fffd:2fff:ffff:ffff:ffff:ffff:ffff:ffff
49fffd:3000::/24fffd:30ff:ffff:ffff:ffff:ffff:ffff:ffff
50fffd:3100::/24fffd:31ff:ffff:ffff:ffff:ffff:ffff:ffff
51fffd:3200::/24fffd:32ff:ffff:ffff:ffff:ffff:ffff:ffff
52fffd:3300::/24fffd:33ff:ffff:ffff:ffff:ffff:ffff:ffff
53fffd:3400::/24fffd:34ff:ffff:ffff:ffff:ffff:ffff:ffff
54fffd:3500::/24fffd:35ff:ffff:ffff:ffff:ffff:ffff:ffff
55fffd:3600::/24fffd:36ff:ffff:ffff:ffff:ffff:ffff:ffff
56fffd:3700::/24fffd:37ff:ffff:ffff:ffff:ffff:ffff:ffff
57fffd:3800::/24fffd:38ff:ffff:ffff:ffff:ffff:ffff:ffff
58fffd:3900::/24fffd:39ff:ffff:ffff:ffff:ffff:ffff:ffff
59fffd:3a00::/24fffd:3aff:ffff:ffff:ffff:ffff:ffff:ffff
60fffd:3b00::/24fffd:3bff:ffff:ffff:ffff:ffff:ffff:ffff
61fffd:3c00::/24fffd:3cff:ffff:ffff:ffff:ffff:ffff:ffff
62fffd:3d00::/24fffd:3dff:ffff:ffff:ffff:ffff:ffff:ffff
63fffd:3e00::/24fffd:3eff:ffff:ffff:ffff:ffff:ffff:ffff
64fffd:3f00::/24fffd:3fff:ffff:ffff:ffff:ffff:ffff:ffff
65fffd:4000::/24fffd:40ff:ffff:ffff:ffff:ffff:ffff:ffff
66fffd:4100::/24fffd:41ff:ffff:ffff:ffff:ffff:ffff:ffff
67fffd:4200::/24fffd:42ff:ffff:ffff:ffff:ffff:ffff:ffff
68fffd:4300::/24fffd:43ff:ffff:ffff:ffff:ffff:ffff:ffff
69fffd:4400::/24fffd:44ff:ffff:ffff:ffff:ffff:ffff:ffff
70fffd:4500::/24fffd:45ff:ffff:ffff:ffff:ffff:ffff:ffff
71fffd:4600::/24fffd:46ff:ffff:ffff:ffff:ffff:ffff:ffff
72fffd:4700::/24fffd:47ff:ffff:ffff:ffff:ffff:ffff:ffff
73fffd:4800::/24fffd:48ff:ffff:ffff:ffff:ffff:ffff:ffff
74fffd:4900::/24fffd:49ff:ffff:ffff:ffff:ffff:ffff:ffff
75fffd:4a00::/24fffd:4aff:ffff:ffff:ffff:ffff:ffff:ffff
76fffd:4b00::/24fffd:4bff:ffff:ffff:ffff:ffff:ffff:ffff
77fffd:4c00::/24fffd:4cff:ffff:ffff:ffff:ffff:ffff:ffff
78fffd:4d00::/24fffd:4dff:ffff:ffff:ffff:ffff:ffff:ffff
79fffd:4e00::/24fffd:4eff:ffff:ffff:ffff:ffff:ffff:ffff
80fffd:4f00::/24fffd:4fff:ffff:ffff:ffff:ffff:ffff:ffff
81fffd:5000::/24fffd:50ff:ffff:ffff:ffff:ffff:ffff:ffff
82fffd:5100::/24fffd:51ff:ffff:ffff:ffff:ffff:ffff:ffff
83fffd:5200::/24fffd:52ff:ffff:ffff:ffff:ffff:ffff:ffff
84fffd:5300::/24fffd:53ff:ffff:ffff:ffff:ffff:ffff:ffff
85fffd:5400::/24fffd:54ff:ffff:ffff:ffff:ffff:ffff:ffff
86fffd:5500::/24fffd:55ff:ffff:ffff:ffff:ffff:ffff:ffff
87fffd:5600::/24fffd:56ff:ffff:ffff:ffff:ffff:ffff:ffff
88fffd:5700::/24fffd:57ff:ffff:ffff:ffff:ffff:ffff:ffff
89fffd:5800::/24fffd:58ff:ffff:ffff:ffff:ffff:ffff:ffff
90fffd:5900::/24fffd:59ff:ffff:ffff:ffff:ffff:ffff:ffff
91fffd:5a00::/24fffd:5aff:ffff:ffff:ffff:ffff:ffff:ffff
92fffd:5b00::/24fffd:5bff:ffff:ffff:ffff:ffff:ffff:ffff
93fffd:5c00::/24fffd:5cff:ffff:ffff:ffff:ffff:ffff:ffff
94fffd:5d00::/24fffd:5dff:ffff:ffff:ffff:ffff:ffff:ffff
95fffd:5e00::/24fffd:5eff:ffff:ffff:ffff:ffff:ffff:ffff
96fffd:5f00::/24fffd:5fff:ffff:ffff:ffff:ffff:ffff:ffff
97fffd:6000::/24fffd:60ff:ffff:ffff:ffff:ffff:ffff:ffff
98fffd:6100::/24fffd:61ff:ffff:ffff:ffff:ffff:ffff:ffff
99fffd:6200::/24fffd:62ff:ffff:ffff:ffff:ffff:ffff:ffff
100fffd:6300::/24fffd:63ff:ffff:ffff:ffff:ffff:ffff:ffff
101fffd:6400::/24fffd:64ff:ffff:ffff:ffff:ffff:ffff:ffff
102fffd:6500::/24fffd:65ff:ffff:ffff:ffff:ffff:ffff:ffff
103fffd:6600::/24fffd:66ff:ffff:ffff:ffff:ffff:ffff:ffff
104fffd:6700::/24fffd:67ff:ffff:ffff:ffff:ffff:ffff:ffff
105fffd:6800::/24fffd:68ff:ffff:ffff:ffff:ffff:ffff:ffff
106fffd:6900::/24fffd:69ff:ffff:ffff:ffff:ffff:ffff:ffff
107fffd:6a00::/24fffd:6aff:ffff:ffff:ffff:ffff:ffff:ffff
108fffd:6b00::/24fffd:6bff:ffff:ffff:ffff:ffff:ffff:ffff
109fffd:6c00::/24fffd:6cff:ffff:ffff:ffff:ffff:ffff:ffff
110fffd:6d00::/24fffd:6dff:ffff:ffff:ffff:ffff:ffff:ffff
111fffd:6e00::/24fffd:6eff:ffff:ffff:ffff:ffff:ffff:ffff
112fffd:6f00::/24fffd:6fff:ffff:ffff:ffff:ffff:ffff:ffff
113fffd:7000::/24fffd:70ff:ffff:ffff:ffff:ffff:ffff:ffff
114fffd:7100::/24fffd:71ff:ffff:ffff:ffff:ffff:ffff:ffff
115fffd:7200::/24fffd:72ff:ffff:ffff:ffff:ffff:ffff:ffff
116fffd:7300::/24fffd:73ff:ffff:ffff:ffff:ffff:ffff:ffff
117fffd:7400::/24fffd:74ff:ffff:ffff:ffff:ffff:ffff:ffff
118fffd:7500::/24fffd:75ff:ffff:ffff:ffff:ffff:ffff:ffff
119fffd:7600::/24fffd:76ff:ffff:ffff:ffff:ffff:ffff:ffff
120fffd:7700::/24fffd:77ff:ffff:ffff:ffff:ffff:ffff:ffff
121fffd:7800::/24fffd:78ff:ffff:ffff:ffff:ffff:ffff:ffff
122fffd:7900::/24fffd:79ff:ffff:ffff:ffff:ffff:ffff:ffff
123fffd:7a00::/24fffd:7aff:ffff:ffff:ffff:ffff:ffff:ffff
124fffd:7b00::/24fffd:7bff:ffff:ffff:ffff:ffff:ffff:ffff
125fffd:7c00::/24fffd:7cff:ffff:ffff:ffff:ffff:ffff:ffff
126fffd:7d00::/24fffd:7dff:ffff:ffff:ffff:ffff:ffff:ffff
127fffd:7e00::/24fffd:7eff:ffff:ffff:ffff:ffff:ffff:ffff
128fffd:7f00::/24fffd:7fff:ffff:ffff:ffff:ffff:ffff:ffff
129fffd:8000::/24fffd:80ff:ffff:ffff:ffff:ffff:ffff:ffff
130fffd:8100::/24fffd:81ff:ffff:ffff:ffff:ffff:ffff:ffff
131fffd:8200::/24fffd:82ff:ffff:ffff:ffff:ffff:ffff:ffff
132fffd:8300::/24fffd:83ff:ffff:ffff:ffff:ffff:ffff:ffff
133fffd:8400::/24fffd:84ff:ffff:ffff:ffff:ffff:ffff:ffff
134fffd:8500::/24fffd:85ff:ffff:ffff:ffff:ffff:ffff:ffff
135fffd:8600::/24fffd:86ff:ffff:ffff:ffff:ffff:ffff:ffff
136fffd:8700::/24fffd:87ff:ffff:ffff:ffff:ffff:ffff:ffff
137fffd:8800::/24fffd:88ff:ffff:ffff:ffff:ffff:ffff:ffff
138fffd:8900::/24fffd:89ff:ffff:ffff:ffff:ffff:ffff:ffff
139fffd:8a00::/24fffd:8aff:ffff:ffff:ffff:ffff:ffff:ffff
140fffd:8b00::/24fffd:8bff:ffff:ffff:ffff:ffff:ffff:ffff
141fffd:8c00::/24fffd:8cff:ffff:ffff:ffff:ffff:ffff:ffff
142fffd:8d00::/24fffd:8dff:ffff:ffff:ffff:ffff:ffff:ffff
143fffd:8e00::/24fffd:8eff:ffff:ffff:ffff:ffff:ffff:ffff
144fffd:8f00::/24fffd:8fff:ffff:ffff:ffff:ffff:ffff:ffff
145fffd:9000::/24fffd:90ff:ffff:ffff:ffff:ffff:ffff:ffff
146fffd:9100::/24fffd:91ff:ffff:ffff:ffff:ffff:ffff:ffff
147fffd:9200::/24fffd:92ff:ffff:ffff:ffff:ffff:ffff:ffff
148fffd:9300::/24fffd:93ff:ffff:ffff:ffff:ffff:ffff:ffff
149fffd:9400::/24fffd:94ff:ffff:ffff:ffff:ffff:ffff:ffff
150fffd:9500::/24fffd:95ff:ffff:ffff:ffff:ffff:ffff:ffff
151fffd:9600::/24fffd:96ff:ffff:ffff:ffff:ffff:ffff:ffff
152fffd:9700::/24fffd:97ff:ffff:ffff:ffff:ffff:ffff:ffff
153fffd:9800::/24fffd:98ff:ffff:ffff:ffff:ffff:ffff:ffff
154fffd:9900::/24fffd:99ff:ffff:ffff:ffff:ffff:ffff:ffff
155fffd:9a00::/24fffd:9aff:ffff:ffff:ffff:ffff:ffff:ffff
156fffd:9b00::/24fffd:9bff:ffff:ffff:ffff:ffff:ffff:ffff
157fffd:9c00::/24fffd:9cff:ffff:ffff:ffff:ffff:ffff:ffff
158fffd:9d00::/24fffd:9dff:ffff:ffff:ffff:ffff:ffff:ffff
159fffd:9e00::/24fffd:9eff:ffff:ffff:ffff:ffff:ffff:ffff
160fffd:9f00::/24fffd:9fff:ffff:ffff:ffff:ffff:ffff:ffff
161fffd:a000::/24fffd:a0ff:ffff:ffff:ffff:ffff:ffff:ffff
162fffd:a100::/24fffd:a1ff:ffff:ffff:ffff:ffff:ffff:ffff
163fffd:a200::/24fffd:a2ff:ffff:ffff:ffff:ffff:ffff:ffff
164fffd:a300::/24fffd:a3ff:ffff:ffff:ffff:ffff:ffff:ffff
165fffd:a400::/24fffd:a4ff:ffff:ffff:ffff:ffff:ffff:ffff
166fffd:a500::/24fffd:a5ff:ffff:ffff:ffff:ffff:ffff:ffff
167fffd:a600::/24fffd:a6ff:ffff:ffff:ffff:ffff:ffff:ffff
168fffd:a700::/24fffd:a7ff:ffff:ffff:ffff:ffff:ffff:ffff
169fffd:a800::/24fffd:a8ff:ffff:ffff:ffff:ffff:ffff:ffff
170fffd:a900::/24fffd:a9ff:ffff:ffff:ffff:ffff:ffff:ffff
171fffd:aa00::/24fffd:aaff:ffff:ffff:ffff:ffff:ffff:ffff
172fffd:ab00::/24fffd:abff:ffff:ffff:ffff:ffff:ffff:ffff
173fffd:ac00::/24fffd:acff:ffff:ffff:ffff:ffff:ffff:ffff
174fffd:ad00::/24fffd:adff:ffff:ffff:ffff:ffff:ffff:ffff
175fffd:ae00::/24fffd:aeff:ffff:ffff:ffff:ffff:ffff:ffff
176fffd:af00::/24fffd:afff:ffff:ffff:ffff:ffff:ffff:ffff
177fffd:b000::/24fffd:b0ff:ffff:ffff:ffff:ffff:ffff:ffff
178fffd:b100::/24fffd:b1ff:ffff:ffff:ffff:ffff:ffff:ffff
179fffd:b200::/24fffd:b2ff:ffff:ffff:ffff:ffff:ffff:ffff
180fffd:b300::/24fffd:b3ff:ffff:ffff:ffff:ffff:ffff:ffff
181fffd:b400::/24fffd:b4ff:ffff:ffff:ffff:ffff:ffff:ffff
182fffd:b500::/24fffd:b5ff:ffff:ffff:ffff:ffff:ffff:ffff
183fffd:b600::/24fffd:b6ff:ffff:ffff:ffff:ffff:ffff:ffff
184fffd:b700::/24fffd:b7ff:ffff:ffff:ffff:ffff:ffff:ffff
185fffd:b800::/24fffd:b8ff:ffff:ffff:ffff:ffff:ffff:ffff
186fffd:b900::/24fffd:b9ff:ffff:ffff:ffff:ffff:ffff:ffff
187fffd:ba00::/24fffd:baff:ffff:ffff:ffff:ffff:ffff:ffff
188fffd:bb00::/24fffd:bbff:ffff:ffff:ffff:ffff:ffff:ffff
189fffd:bc00::/24fffd:bcff:ffff:ffff:ffff:ffff:ffff:ffff
190fffd:bd00::/24fffd:bdff:ffff:ffff:ffff:ffff:ffff:ffff
191fffd:be00::/24fffd:beff:ffff:ffff:ffff:ffff:ffff:ffff
192fffd:bf00::/24fffd:bfff:ffff:ffff:ffff:ffff:ffff:ffff
193fffd:c000::/24fffd:c0ff:ffff:ffff:ffff:ffff:ffff:ffff
194fffd:c100::/24fffd:c1ff:ffff:ffff:ffff:ffff:ffff:ffff
195fffd:c200::/24fffd:c2ff:ffff:ffff:ffff:ffff:ffff:ffff
196fffd:c300::/24fffd:c3ff:ffff:ffff:ffff:ffff:ffff:ffff
197fffd:c400::/24fffd:c4ff:ffff:ffff:ffff:ffff:ffff:ffff
198fffd:c500::/24fffd:c5ff:ffff:ffff:ffff:ffff:ffff:ffff
199fffd:c600::/24fffd:c6ff:ffff:ffff:ffff:ffff:ffff:ffff
200fffd:c700::/24fffd:c7ff:ffff:ffff:ffff:ffff:ffff:ffff
201fffd:c800::/24fffd:c8ff:ffff:ffff:ffff:ffff:ffff:ffff
202fffd:c900::/24fffd:c9ff:ffff:ffff:ffff:ffff:ffff:ffff
203fffd:ca00::/24fffd:caff:ffff:ffff:ffff:ffff:ffff:ffff
204fffd:cb00::/24fffd:cbff:ffff:ffff:ffff:ffff:ffff:ffff
205fffd:cc00::/24fffd:ccff:ffff:ffff:ffff:ffff:ffff:ffff
206fffd:cd00::/24fffd:cdff:ffff:ffff:ffff:ffff:ffff:ffff
207fffd:ce00::/24fffd:ceff:ffff:ffff:ffff:ffff:ffff:ffff
208fffd:cf00::/24fffd:cfff:ffff:ffff:ffff:ffff:ffff:ffff
209fffd:d000::/24fffd:d0ff:ffff:ffff:ffff:ffff:ffff:ffff
210fffd:d100::/24fffd:d1ff:ffff:ffff:ffff:ffff:ffff:ffff
211fffd:d200::/24fffd:d2ff:ffff:ffff:ffff:ffff:ffff:ffff
212fffd:d300::/24fffd:d3ff:ffff:ffff:ffff:ffff:ffff:ffff
213fffd:d400::/24fffd:d4ff:ffff:ffff:ffff:ffff:ffff:ffff
214fffd:d500::/24fffd:d5ff:ffff:ffff:ffff:ffff:ffff:ffff
215fffd:d600::/24fffd:d6ff:ffff:ffff:ffff:ffff:ffff:ffff
216fffd:d700::/24fffd:d7ff:ffff:ffff:ffff:ffff:ffff:ffff
217fffd:d800::/24fffd:d8ff:ffff:ffff:ffff:ffff:ffff:ffff
218fffd:d900::/24fffd:d9ff:ffff:ffff:ffff:ffff:ffff:ffff
219fffd:da00::/24fffd:daff:ffff:ffff:ffff:ffff:ffff:ffff
220fffd:db00::/24fffd:dbff:ffff:ffff:ffff:ffff:ffff:ffff
221fffd:dc00::/24fffd:dcff:ffff:ffff:ffff:ffff:ffff:ffff
222fffd:dd00::/24fffd:ddff:ffff:ffff:ffff:ffff:ffff:ffff
223fffd:de00::/24fffd:deff:ffff:ffff:ffff:ffff:ffff:ffff
224fffd:df00::/24fffd:dfff:ffff:ffff:ffff:ffff:ffff:ffff
225fffd:e000::/24fffd:e0ff:ffff:ffff:ffff:ffff:ffff:ffff
226fffd:e100::/24fffd:e1ff:ffff:ffff:ffff:ffff:ffff:ffff
227fffd:e200::/24fffd:e2ff:ffff:ffff:ffff:ffff:ffff:ffff
228fffd:e300::/24fffd:e3ff:ffff:ffff:ffff:ffff:ffff:ffff
229fffd:e400::/24fffd:e4ff:ffff:ffff:ffff:ffff:ffff:ffff
230fffd:e500::/24fffd:e5ff:ffff:ffff:ffff:ffff:ffff:ffff
231fffd:e600::/24fffd:e6ff:ffff:ffff:ffff:ffff:ffff:ffff
232fffd:e700::/24fffd:e7ff:ffff:ffff:ffff:ffff:ffff:ffff
233fffd:e800::/24fffd:e8ff:ffff:ffff:ffff:ffff:ffff:ffff
234fffd:e900::/24fffd:e9ff:ffff:ffff:ffff:ffff:ffff:ffff
235fffd:ea00::/24fffd:eaff:ffff:ffff:ffff:ffff:ffff:ffff
236fffd:eb00::/24fffd:ebff:ffff:ffff:ffff:ffff:ffff:ffff
237fffd:ec00::/24fffd:ecff:ffff:ffff:ffff:ffff:ffff:ffff
238fffd:ed00::/24fffd:edff:ffff:ffff:ffff:ffff:ffff:ffff
239fffd:ee00::/24fffd:eeff:ffff:ffff:ffff:ffff:ffff:ffff
240fffd:ef00::/24fffd:efff:ffff:ffff:ffff:ffff:ffff:ffff
241fffd:f000::/24fffd:f0ff:ffff:ffff:ffff:ffff:ffff:ffff
242fffd:f100::/24fffd:f1ff:ffff:ffff:ffff:ffff:ffff:ffff
243fffd:f200::/24fffd:f2ff:ffff:ffff:ffff:ffff:ffff:ffff
244fffd:f300::/24fffd:f3ff:ffff:ffff:ffff:ffff:ffff:ffff
245fffd:f400::/24fffd:f4ff:ffff:ffff:ffff:ffff:ffff:ffff
246fffd:f500::/24fffd:f5ff:ffff:ffff:ffff:ffff:ffff:ffff
247fffd:f600::/24fffd:f6ff:ffff:ffff:ffff:ffff:ffff:ffff
248fffd:f700::/24fffd:f7ff:ffff:ffff:ffff:ffff:ffff:ffff
249fffd:f800::/24fffd:f8ff:ffff:ffff:ffff:ffff:ffff:ffff
250fffd:f900::/24fffd:f9ff:ffff:ffff:ffff:ffff:ffff:ffff
251fffd:fa00::/24fffd:faff:ffff:ffff:ffff:ffff:ffff:ffff
252fffd:fb00::/24fffd:fbff:ffff:ffff:ffff:ffff:ffff:ffff
253fffd:fc00::/24fffd:fcff:ffff:ffff:ffff:ffff:ffff:ffff
254fffd:fd00::/24fffd:fdff:ffff:ffff:ffff:ffff:ffff:ffff
255fffd:fe00::/24fffd:feff:ffff:ffff:ffff:ffff:ffff:ffff
256fffd:ff00::/24fffd: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.