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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
fffa::/16
First address
fffa::
Last address
fffa: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
fffa:0000:0000:0000:0000:0000:0000:0000
Type
Multicast ff00::/8
One-to-many traffic; replaces broadcast
Reverse DNS zone
a.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)

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

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