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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
ff99::/16
First address
ff99::
Last address
ff99: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
ff99:0000:0000:0000:0000:0000:0000:0000
Type
Multicast ff00::/8
One-to-many traffic; replaces broadcast
Reverse DNS zone
9.9.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)

ff99::/16 makes 256 subnets of /24.

Subnets
#SubnetLast address
1ff99::/24ff99:ff:ffff:ffff:ffff:ffff:ffff:ffff
2ff99:100::/24ff99:1ff:ffff:ffff:ffff:ffff:ffff:ffff
3ff99:200::/24ff99:2ff:ffff:ffff:ffff:ffff:ffff:ffff
4ff99:300::/24ff99:3ff:ffff:ffff:ffff:ffff:ffff:ffff
5ff99:400::/24ff99:4ff:ffff:ffff:ffff:ffff:ffff:ffff
6ff99:500::/24ff99:5ff:ffff:ffff:ffff:ffff:ffff:ffff
7ff99:600::/24ff99:6ff:ffff:ffff:ffff:ffff:ffff:ffff
8ff99:700::/24ff99:7ff:ffff:ffff:ffff:ffff:ffff:ffff
9ff99:800::/24ff99:8ff:ffff:ffff:ffff:ffff:ffff:ffff
10ff99:900::/24ff99:9ff:ffff:ffff:ffff:ffff:ffff:ffff
11ff99:a00::/24ff99:aff:ffff:ffff:ffff:ffff:ffff:ffff
12ff99:b00::/24ff99:bff:ffff:ffff:ffff:ffff:ffff:ffff
13ff99:c00::/24ff99:cff:ffff:ffff:ffff:ffff:ffff:ffff
14ff99:d00::/24ff99:dff:ffff:ffff:ffff:ffff:ffff:ffff
15ff99:e00::/24ff99:eff:ffff:ffff:ffff:ffff:ffff:ffff
16ff99:f00::/24ff99:fff:ffff:ffff:ffff:ffff:ffff:ffff
17ff99:1000::/24ff99:10ff:ffff:ffff:ffff:ffff:ffff:ffff
18ff99:1100::/24ff99:11ff:ffff:ffff:ffff:ffff:ffff:ffff
19ff99:1200::/24ff99:12ff:ffff:ffff:ffff:ffff:ffff:ffff
20ff99:1300::/24ff99:13ff:ffff:ffff:ffff:ffff:ffff:ffff
21ff99:1400::/24ff99:14ff:ffff:ffff:ffff:ffff:ffff:ffff
22ff99:1500::/24ff99:15ff:ffff:ffff:ffff:ffff:ffff:ffff
23ff99:1600::/24ff99:16ff:ffff:ffff:ffff:ffff:ffff:ffff
24ff99:1700::/24ff99:17ff:ffff:ffff:ffff:ffff:ffff:ffff
25ff99:1800::/24ff99:18ff:ffff:ffff:ffff:ffff:ffff:ffff
26ff99:1900::/24ff99:19ff:ffff:ffff:ffff:ffff:ffff:ffff
27ff99:1a00::/24ff99:1aff:ffff:ffff:ffff:ffff:ffff:ffff
28ff99:1b00::/24ff99:1bff:ffff:ffff:ffff:ffff:ffff:ffff
29ff99:1c00::/24ff99:1cff:ffff:ffff:ffff:ffff:ffff:ffff
30ff99:1d00::/24ff99:1dff:ffff:ffff:ffff:ffff:ffff:ffff
31ff99:1e00::/24ff99:1eff:ffff:ffff:ffff:ffff:ffff:ffff
32ff99:1f00::/24ff99:1fff:ffff:ffff:ffff:ffff:ffff:ffff
33ff99:2000::/24ff99:20ff:ffff:ffff:ffff:ffff:ffff:ffff
34ff99:2100::/24ff99:21ff:ffff:ffff:ffff:ffff:ffff:ffff
35ff99:2200::/24ff99:22ff:ffff:ffff:ffff:ffff:ffff:ffff
36ff99:2300::/24ff99:23ff:ffff:ffff:ffff:ffff:ffff:ffff
37ff99:2400::/24ff99:24ff:ffff:ffff:ffff:ffff:ffff:ffff
38ff99:2500::/24ff99:25ff:ffff:ffff:ffff:ffff:ffff:ffff
39ff99:2600::/24ff99:26ff:ffff:ffff:ffff:ffff:ffff:ffff
40ff99:2700::/24ff99:27ff:ffff:ffff:ffff:ffff:ffff:ffff
41ff99:2800::/24ff99:28ff:ffff:ffff:ffff:ffff:ffff:ffff
42ff99:2900::/24ff99:29ff:ffff:ffff:ffff:ffff:ffff:ffff
43ff99:2a00::/24ff99:2aff:ffff:ffff:ffff:ffff:ffff:ffff
44ff99:2b00::/24ff99:2bff:ffff:ffff:ffff:ffff:ffff:ffff
45ff99:2c00::/24ff99:2cff:ffff:ffff:ffff:ffff:ffff:ffff
46ff99:2d00::/24ff99:2dff:ffff:ffff:ffff:ffff:ffff:ffff
47ff99:2e00::/24ff99:2eff:ffff:ffff:ffff:ffff:ffff:ffff
48ff99:2f00::/24ff99:2fff:ffff:ffff:ffff:ffff:ffff:ffff
49ff99:3000::/24ff99:30ff:ffff:ffff:ffff:ffff:ffff:ffff
50ff99:3100::/24ff99:31ff:ffff:ffff:ffff:ffff:ffff:ffff
51ff99:3200::/24ff99:32ff:ffff:ffff:ffff:ffff:ffff:ffff
52ff99:3300::/24ff99:33ff:ffff:ffff:ffff:ffff:ffff:ffff
53ff99:3400::/24ff99:34ff:ffff:ffff:ffff:ffff:ffff:ffff
54ff99:3500::/24ff99:35ff:ffff:ffff:ffff:ffff:ffff:ffff
55ff99:3600::/24ff99:36ff:ffff:ffff:ffff:ffff:ffff:ffff
56ff99:3700::/24ff99:37ff:ffff:ffff:ffff:ffff:ffff:ffff
57ff99:3800::/24ff99:38ff:ffff:ffff:ffff:ffff:ffff:ffff
58ff99:3900::/24ff99:39ff:ffff:ffff:ffff:ffff:ffff:ffff
59ff99:3a00::/24ff99:3aff:ffff:ffff:ffff:ffff:ffff:ffff
60ff99:3b00::/24ff99:3bff:ffff:ffff:ffff:ffff:ffff:ffff
61ff99:3c00::/24ff99:3cff:ffff:ffff:ffff:ffff:ffff:ffff
62ff99:3d00::/24ff99:3dff:ffff:ffff:ffff:ffff:ffff:ffff
63ff99:3e00::/24ff99:3eff:ffff:ffff:ffff:ffff:ffff:ffff
64ff99:3f00::/24ff99:3fff:ffff:ffff:ffff:ffff:ffff:ffff
65ff99:4000::/24ff99:40ff:ffff:ffff:ffff:ffff:ffff:ffff
66ff99:4100::/24ff99:41ff:ffff:ffff:ffff:ffff:ffff:ffff
67ff99:4200::/24ff99:42ff:ffff:ffff:ffff:ffff:ffff:ffff
68ff99:4300::/24ff99:43ff:ffff:ffff:ffff:ffff:ffff:ffff
69ff99:4400::/24ff99:44ff:ffff:ffff:ffff:ffff:ffff:ffff
70ff99:4500::/24ff99:45ff:ffff:ffff:ffff:ffff:ffff:ffff
71ff99:4600::/24ff99:46ff:ffff:ffff:ffff:ffff:ffff:ffff
72ff99:4700::/24ff99:47ff:ffff:ffff:ffff:ffff:ffff:ffff
73ff99:4800::/24ff99:48ff:ffff:ffff:ffff:ffff:ffff:ffff
74ff99:4900::/24ff99:49ff:ffff:ffff:ffff:ffff:ffff:ffff
75ff99:4a00::/24ff99:4aff:ffff:ffff:ffff:ffff:ffff:ffff
76ff99:4b00::/24ff99:4bff:ffff:ffff:ffff:ffff:ffff:ffff
77ff99:4c00::/24ff99:4cff:ffff:ffff:ffff:ffff:ffff:ffff
78ff99:4d00::/24ff99:4dff:ffff:ffff:ffff:ffff:ffff:ffff
79ff99:4e00::/24ff99:4eff:ffff:ffff:ffff:ffff:ffff:ffff
80ff99:4f00::/24ff99:4fff:ffff:ffff:ffff:ffff:ffff:ffff
81ff99:5000::/24ff99:50ff:ffff:ffff:ffff:ffff:ffff:ffff
82ff99:5100::/24ff99:51ff:ffff:ffff:ffff:ffff:ffff:ffff
83ff99:5200::/24ff99:52ff:ffff:ffff:ffff:ffff:ffff:ffff
84ff99:5300::/24ff99:53ff:ffff:ffff:ffff:ffff:ffff:ffff
85ff99:5400::/24ff99:54ff:ffff:ffff:ffff:ffff:ffff:ffff
86ff99:5500::/24ff99:55ff:ffff:ffff:ffff:ffff:ffff:ffff
87ff99:5600::/24ff99:56ff:ffff:ffff:ffff:ffff:ffff:ffff
88ff99:5700::/24ff99:57ff:ffff:ffff:ffff:ffff:ffff:ffff
89ff99:5800::/24ff99:58ff:ffff:ffff:ffff:ffff:ffff:ffff
90ff99:5900::/24ff99:59ff:ffff:ffff:ffff:ffff:ffff:ffff
91ff99:5a00::/24ff99:5aff:ffff:ffff:ffff:ffff:ffff:ffff
92ff99:5b00::/24ff99:5bff:ffff:ffff:ffff:ffff:ffff:ffff
93ff99:5c00::/24ff99:5cff:ffff:ffff:ffff:ffff:ffff:ffff
94ff99:5d00::/24ff99:5dff:ffff:ffff:ffff:ffff:ffff:ffff
95ff99:5e00::/24ff99:5eff:ffff:ffff:ffff:ffff:ffff:ffff
96ff99:5f00::/24ff99:5fff:ffff:ffff:ffff:ffff:ffff:ffff
97ff99:6000::/24ff99:60ff:ffff:ffff:ffff:ffff:ffff:ffff
98ff99:6100::/24ff99:61ff:ffff:ffff:ffff:ffff:ffff:ffff
99ff99:6200::/24ff99:62ff:ffff:ffff:ffff:ffff:ffff:ffff
100ff99:6300::/24ff99:63ff:ffff:ffff:ffff:ffff:ffff:ffff
101ff99:6400::/24ff99:64ff:ffff:ffff:ffff:ffff:ffff:ffff
102ff99:6500::/24ff99:65ff:ffff:ffff:ffff:ffff:ffff:ffff
103ff99:6600::/24ff99:66ff:ffff:ffff:ffff:ffff:ffff:ffff
104ff99:6700::/24ff99:67ff:ffff:ffff:ffff:ffff:ffff:ffff
105ff99:6800::/24ff99:68ff:ffff:ffff:ffff:ffff:ffff:ffff
106ff99:6900::/24ff99:69ff:ffff:ffff:ffff:ffff:ffff:ffff
107ff99:6a00::/24ff99:6aff:ffff:ffff:ffff:ffff:ffff:ffff
108ff99:6b00::/24ff99:6bff:ffff:ffff:ffff:ffff:ffff:ffff
109ff99:6c00::/24ff99:6cff:ffff:ffff:ffff:ffff:ffff:ffff
110ff99:6d00::/24ff99:6dff:ffff:ffff:ffff:ffff:ffff:ffff
111ff99:6e00::/24ff99:6eff:ffff:ffff:ffff:ffff:ffff:ffff
112ff99:6f00::/24ff99:6fff:ffff:ffff:ffff:ffff:ffff:ffff
113ff99:7000::/24ff99:70ff:ffff:ffff:ffff:ffff:ffff:ffff
114ff99:7100::/24ff99:71ff:ffff:ffff:ffff:ffff:ffff:ffff
115ff99:7200::/24ff99:72ff:ffff:ffff:ffff:ffff:ffff:ffff
116ff99:7300::/24ff99:73ff:ffff:ffff:ffff:ffff:ffff:ffff
117ff99:7400::/24ff99:74ff:ffff:ffff:ffff:ffff:ffff:ffff
118ff99:7500::/24ff99:75ff:ffff:ffff:ffff:ffff:ffff:ffff
119ff99:7600::/24ff99:76ff:ffff:ffff:ffff:ffff:ffff:ffff
120ff99:7700::/24ff99:77ff:ffff:ffff:ffff:ffff:ffff:ffff
121ff99:7800::/24ff99:78ff:ffff:ffff:ffff:ffff:ffff:ffff
122ff99:7900::/24ff99:79ff:ffff:ffff:ffff:ffff:ffff:ffff
123ff99:7a00::/24ff99:7aff:ffff:ffff:ffff:ffff:ffff:ffff
124ff99:7b00::/24ff99:7bff:ffff:ffff:ffff:ffff:ffff:ffff
125ff99:7c00::/24ff99:7cff:ffff:ffff:ffff:ffff:ffff:ffff
126ff99:7d00::/24ff99:7dff:ffff:ffff:ffff:ffff:ffff:ffff
127ff99:7e00::/24ff99:7eff:ffff:ffff:ffff:ffff:ffff:ffff
128ff99:7f00::/24ff99:7fff:ffff:ffff:ffff:ffff:ffff:ffff
129ff99:8000::/24ff99:80ff:ffff:ffff:ffff:ffff:ffff:ffff
130ff99:8100::/24ff99:81ff:ffff:ffff:ffff:ffff:ffff:ffff
131ff99:8200::/24ff99:82ff:ffff:ffff:ffff:ffff:ffff:ffff
132ff99:8300::/24ff99:83ff:ffff:ffff:ffff:ffff:ffff:ffff
133ff99:8400::/24ff99:84ff:ffff:ffff:ffff:ffff:ffff:ffff
134ff99:8500::/24ff99:85ff:ffff:ffff:ffff:ffff:ffff:ffff
135ff99:8600::/24ff99:86ff:ffff:ffff:ffff:ffff:ffff:ffff
136ff99:8700::/24ff99:87ff:ffff:ffff:ffff:ffff:ffff:ffff
137ff99:8800::/24ff99:88ff:ffff:ffff:ffff:ffff:ffff:ffff
138ff99:8900::/24ff99:89ff:ffff:ffff:ffff:ffff:ffff:ffff
139ff99:8a00::/24ff99:8aff:ffff:ffff:ffff:ffff:ffff:ffff
140ff99:8b00::/24ff99:8bff:ffff:ffff:ffff:ffff:ffff:ffff
141ff99:8c00::/24ff99:8cff:ffff:ffff:ffff:ffff:ffff:ffff
142ff99:8d00::/24ff99:8dff:ffff:ffff:ffff:ffff:ffff:ffff
143ff99:8e00::/24ff99:8eff:ffff:ffff:ffff:ffff:ffff:ffff
144ff99:8f00::/24ff99:8fff:ffff:ffff:ffff:ffff:ffff:ffff
145ff99:9000::/24ff99:90ff:ffff:ffff:ffff:ffff:ffff:ffff
146ff99:9100::/24ff99:91ff:ffff:ffff:ffff:ffff:ffff:ffff
147ff99:9200::/24ff99:92ff:ffff:ffff:ffff:ffff:ffff:ffff
148ff99:9300::/24ff99:93ff:ffff:ffff:ffff:ffff:ffff:ffff
149ff99:9400::/24ff99:94ff:ffff:ffff:ffff:ffff:ffff:ffff
150ff99:9500::/24ff99:95ff:ffff:ffff:ffff:ffff:ffff:ffff
151ff99:9600::/24ff99:96ff:ffff:ffff:ffff:ffff:ffff:ffff
152ff99:9700::/24ff99:97ff:ffff:ffff:ffff:ffff:ffff:ffff
153ff99:9800::/24ff99:98ff:ffff:ffff:ffff:ffff:ffff:ffff
154ff99:9900::/24ff99:99ff:ffff:ffff:ffff:ffff:ffff:ffff
155ff99:9a00::/24ff99:9aff:ffff:ffff:ffff:ffff:ffff:ffff
156ff99:9b00::/24ff99:9bff:ffff:ffff:ffff:ffff:ffff:ffff
157ff99:9c00::/24ff99:9cff:ffff:ffff:ffff:ffff:ffff:ffff
158ff99:9d00::/24ff99:9dff:ffff:ffff:ffff:ffff:ffff:ffff
159ff99:9e00::/24ff99:9eff:ffff:ffff:ffff:ffff:ffff:ffff
160ff99:9f00::/24ff99:9fff:ffff:ffff:ffff:ffff:ffff:ffff
161ff99:a000::/24ff99:a0ff:ffff:ffff:ffff:ffff:ffff:ffff
162ff99:a100::/24ff99:a1ff:ffff:ffff:ffff:ffff:ffff:ffff
163ff99:a200::/24ff99:a2ff:ffff:ffff:ffff:ffff:ffff:ffff
164ff99:a300::/24ff99:a3ff:ffff:ffff:ffff:ffff:ffff:ffff
165ff99:a400::/24ff99:a4ff:ffff:ffff:ffff:ffff:ffff:ffff
166ff99:a500::/24ff99:a5ff:ffff:ffff:ffff:ffff:ffff:ffff
167ff99:a600::/24ff99:a6ff:ffff:ffff:ffff:ffff:ffff:ffff
168ff99:a700::/24ff99:a7ff:ffff:ffff:ffff:ffff:ffff:ffff
169ff99:a800::/24ff99:a8ff:ffff:ffff:ffff:ffff:ffff:ffff
170ff99:a900::/24ff99:a9ff:ffff:ffff:ffff:ffff:ffff:ffff
171ff99:aa00::/24ff99:aaff:ffff:ffff:ffff:ffff:ffff:ffff
172ff99:ab00::/24ff99:abff:ffff:ffff:ffff:ffff:ffff:ffff
173ff99:ac00::/24ff99:acff:ffff:ffff:ffff:ffff:ffff:ffff
174ff99:ad00::/24ff99:adff:ffff:ffff:ffff:ffff:ffff:ffff
175ff99:ae00::/24ff99:aeff:ffff:ffff:ffff:ffff:ffff:ffff
176ff99:af00::/24ff99:afff:ffff:ffff:ffff:ffff:ffff:ffff
177ff99:b000::/24ff99:b0ff:ffff:ffff:ffff:ffff:ffff:ffff
178ff99:b100::/24ff99:b1ff:ffff:ffff:ffff:ffff:ffff:ffff
179ff99:b200::/24ff99:b2ff:ffff:ffff:ffff:ffff:ffff:ffff
180ff99:b300::/24ff99:b3ff:ffff:ffff:ffff:ffff:ffff:ffff
181ff99:b400::/24ff99:b4ff:ffff:ffff:ffff:ffff:ffff:ffff
182ff99:b500::/24ff99:b5ff:ffff:ffff:ffff:ffff:ffff:ffff
183ff99:b600::/24ff99:b6ff:ffff:ffff:ffff:ffff:ffff:ffff
184ff99:b700::/24ff99:b7ff:ffff:ffff:ffff:ffff:ffff:ffff
185ff99:b800::/24ff99:b8ff:ffff:ffff:ffff:ffff:ffff:ffff
186ff99:b900::/24ff99:b9ff:ffff:ffff:ffff:ffff:ffff:ffff
187ff99:ba00::/24ff99:baff:ffff:ffff:ffff:ffff:ffff:ffff
188ff99:bb00::/24ff99:bbff:ffff:ffff:ffff:ffff:ffff:ffff
189ff99:bc00::/24ff99:bcff:ffff:ffff:ffff:ffff:ffff:ffff
190ff99:bd00::/24ff99:bdff:ffff:ffff:ffff:ffff:ffff:ffff
191ff99:be00::/24ff99:beff:ffff:ffff:ffff:ffff:ffff:ffff
192ff99:bf00::/24ff99:bfff:ffff:ffff:ffff:ffff:ffff:ffff
193ff99:c000::/24ff99:c0ff:ffff:ffff:ffff:ffff:ffff:ffff
194ff99:c100::/24ff99:c1ff:ffff:ffff:ffff:ffff:ffff:ffff
195ff99:c200::/24ff99:c2ff:ffff:ffff:ffff:ffff:ffff:ffff
196ff99:c300::/24ff99:c3ff:ffff:ffff:ffff:ffff:ffff:ffff
197ff99:c400::/24ff99:c4ff:ffff:ffff:ffff:ffff:ffff:ffff
198ff99:c500::/24ff99:c5ff:ffff:ffff:ffff:ffff:ffff:ffff
199ff99:c600::/24ff99:c6ff:ffff:ffff:ffff:ffff:ffff:ffff
200ff99:c700::/24ff99:c7ff:ffff:ffff:ffff:ffff:ffff:ffff
201ff99:c800::/24ff99:c8ff:ffff:ffff:ffff:ffff:ffff:ffff
202ff99:c900::/24ff99:c9ff:ffff:ffff:ffff:ffff:ffff:ffff
203ff99:ca00::/24ff99:caff:ffff:ffff:ffff:ffff:ffff:ffff
204ff99:cb00::/24ff99:cbff:ffff:ffff:ffff:ffff:ffff:ffff
205ff99:cc00::/24ff99:ccff:ffff:ffff:ffff:ffff:ffff:ffff
206ff99:cd00::/24ff99:cdff:ffff:ffff:ffff:ffff:ffff:ffff
207ff99:ce00::/24ff99:ceff:ffff:ffff:ffff:ffff:ffff:ffff
208ff99:cf00::/24ff99:cfff:ffff:ffff:ffff:ffff:ffff:ffff
209ff99:d000::/24ff99:d0ff:ffff:ffff:ffff:ffff:ffff:ffff
210ff99:d100::/24ff99:d1ff:ffff:ffff:ffff:ffff:ffff:ffff
211ff99:d200::/24ff99:d2ff:ffff:ffff:ffff:ffff:ffff:ffff
212ff99:d300::/24ff99:d3ff:ffff:ffff:ffff:ffff:ffff:ffff
213ff99:d400::/24ff99:d4ff:ffff:ffff:ffff:ffff:ffff:ffff
214ff99:d500::/24ff99:d5ff:ffff:ffff:ffff:ffff:ffff:ffff
215ff99:d600::/24ff99:d6ff:ffff:ffff:ffff:ffff:ffff:ffff
216ff99:d700::/24ff99:d7ff:ffff:ffff:ffff:ffff:ffff:ffff
217ff99:d800::/24ff99:d8ff:ffff:ffff:ffff:ffff:ffff:ffff
218ff99:d900::/24ff99:d9ff:ffff:ffff:ffff:ffff:ffff:ffff
219ff99:da00::/24ff99:daff:ffff:ffff:ffff:ffff:ffff:ffff
220ff99:db00::/24ff99:dbff:ffff:ffff:ffff:ffff:ffff:ffff
221ff99:dc00::/24ff99:dcff:ffff:ffff:ffff:ffff:ffff:ffff
222ff99:dd00::/24ff99:ddff:ffff:ffff:ffff:ffff:ffff:ffff
223ff99:de00::/24ff99:deff:ffff:ffff:ffff:ffff:ffff:ffff
224ff99:df00::/24ff99:dfff:ffff:ffff:ffff:ffff:ffff:ffff
225ff99:e000::/24ff99:e0ff:ffff:ffff:ffff:ffff:ffff:ffff
226ff99:e100::/24ff99:e1ff:ffff:ffff:ffff:ffff:ffff:ffff
227ff99:e200::/24ff99:e2ff:ffff:ffff:ffff:ffff:ffff:ffff
228ff99:e300::/24ff99:e3ff:ffff:ffff:ffff:ffff:ffff:ffff
229ff99:e400::/24ff99:e4ff:ffff:ffff:ffff:ffff:ffff:ffff
230ff99:e500::/24ff99:e5ff:ffff:ffff:ffff:ffff:ffff:ffff
231ff99:e600::/24ff99:e6ff:ffff:ffff:ffff:ffff:ffff:ffff
232ff99:e700::/24ff99:e7ff:ffff:ffff:ffff:ffff:ffff:ffff
233ff99:e800::/24ff99:e8ff:ffff:ffff:ffff:ffff:ffff:ffff
234ff99:e900::/24ff99:e9ff:ffff:ffff:ffff:ffff:ffff:ffff
235ff99:ea00::/24ff99:eaff:ffff:ffff:ffff:ffff:ffff:ffff
236ff99:eb00::/24ff99:ebff:ffff:ffff:ffff:ffff:ffff:ffff
237ff99:ec00::/24ff99:ecff:ffff:ffff:ffff:ffff:ffff:ffff
238ff99:ed00::/24ff99:edff:ffff:ffff:ffff:ffff:ffff:ffff
239ff99:ee00::/24ff99:eeff:ffff:ffff:ffff:ffff:ffff:ffff
240ff99:ef00::/24ff99:efff:ffff:ffff:ffff:ffff:ffff:ffff
241ff99:f000::/24ff99:f0ff:ffff:ffff:ffff:ffff:ffff:ffff
242ff99:f100::/24ff99:f1ff:ffff:ffff:ffff:ffff:ffff:ffff
243ff99:f200::/24ff99:f2ff:ffff:ffff:ffff:ffff:ffff:ffff
244ff99:f300::/24ff99:f3ff:ffff:ffff:ffff:ffff:ffff:ffff
245ff99:f400::/24ff99:f4ff:ffff:ffff:ffff:ffff:ffff:ffff
246ff99:f500::/24ff99:f5ff:ffff:ffff:ffff:ffff:ffff:ffff
247ff99:f600::/24ff99:f6ff:ffff:ffff:ffff:ffff:ffff:ffff
248ff99:f700::/24ff99:f7ff:ffff:ffff:ffff:ffff:ffff:ffff
249ff99:f800::/24ff99:f8ff:ffff:ffff:ffff:ffff:ffff:ffff
250ff99:f900::/24ff99:f9ff:ffff:ffff:ffff:ffff:ffff:ffff
251ff99:fa00::/24ff99:faff:ffff:ffff:ffff:ffff:ffff:ffff
252ff99:fb00::/24ff99:fbff:ffff:ffff:ffff:ffff:ffff:ffff
253ff99:fc00::/24ff99:fcff:ffff:ffff:ffff:ffff:ffff:ffff
254ff99:fd00::/24ff99:fdff:ffff:ffff:ffff:ffff:ffff:ffff
255ff99:fe00::/24ff99:feff:ffff:ffff:ffff:ffff:ffff:ffff
256ff99:ff00::/24ff99: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.