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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
fcab::/16
First address
fcab::
Last address
fcab: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
fcab:0000:0000:0000:0000:0000:0000:0000
Type
Unique local (ULA) fc00::/7
Private IPv6, like RFC 1918; usually fd00::/8
Reverse DNS zone
b.a.c.f.ip6.arpa
Split into smaller subnets/24
/17 (2)/18 (4)/19 (8)/20 (16)/24 (256)/28 (4,096)/32 (65,536)

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

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