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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
261a::/16
First address
261a::
Last address
261a: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
261a:0000:0000:0000:0000:0000:0000:0000
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zone
a.1.6.2.ip6.arpa
Split into smaller subnets/24
/17 (2)/18 (4)/19 (8)/20 (16)/24 (256)/28 (4,096)/32 (65,536)

261a::/16 makes 256 subnets of /24.

Subnets
#SubnetLast address
1261a::/24261a:ff:ffff:ffff:ffff:ffff:ffff:ffff
2261a:100::/24261a:1ff:ffff:ffff:ffff:ffff:ffff:ffff
3261a:200::/24261a:2ff:ffff:ffff:ffff:ffff:ffff:ffff
4261a:300::/24261a:3ff:ffff:ffff:ffff:ffff:ffff:ffff
5261a:400::/24261a:4ff:ffff:ffff:ffff:ffff:ffff:ffff
6261a:500::/24261a:5ff:ffff:ffff:ffff:ffff:ffff:ffff
7261a:600::/24261a:6ff:ffff:ffff:ffff:ffff:ffff:ffff
8261a:700::/24261a:7ff:ffff:ffff:ffff:ffff:ffff:ffff
9261a:800::/24261a:8ff:ffff:ffff:ffff:ffff:ffff:ffff
10261a:900::/24261a:9ff:ffff:ffff:ffff:ffff:ffff:ffff
11261a:a00::/24261a:aff:ffff:ffff:ffff:ffff:ffff:ffff
12261a:b00::/24261a:bff:ffff:ffff:ffff:ffff:ffff:ffff
13261a:c00::/24261a:cff:ffff:ffff:ffff:ffff:ffff:ffff
14261a:d00::/24261a:dff:ffff:ffff:ffff:ffff:ffff:ffff
15261a:e00::/24261a:eff:ffff:ffff:ffff:ffff:ffff:ffff
16261a:f00::/24261a:fff:ffff:ffff:ffff:ffff:ffff:ffff
17261a:1000::/24261a:10ff:ffff:ffff:ffff:ffff:ffff:ffff
18261a:1100::/24261a:11ff:ffff:ffff:ffff:ffff:ffff:ffff
19261a:1200::/24261a:12ff:ffff:ffff:ffff:ffff:ffff:ffff
20261a:1300::/24261a:13ff:ffff:ffff:ffff:ffff:ffff:ffff
21261a:1400::/24261a:14ff:ffff:ffff:ffff:ffff:ffff:ffff
22261a:1500::/24261a:15ff:ffff:ffff:ffff:ffff:ffff:ffff
23261a:1600::/24261a:16ff:ffff:ffff:ffff:ffff:ffff:ffff
24261a:1700::/24261a:17ff:ffff:ffff:ffff:ffff:ffff:ffff
25261a:1800::/24261a:18ff:ffff:ffff:ffff:ffff:ffff:ffff
26261a:1900::/24261a:19ff:ffff:ffff:ffff:ffff:ffff:ffff
27261a:1a00::/24261a:1aff:ffff:ffff:ffff:ffff:ffff:ffff
28261a:1b00::/24261a:1bff:ffff:ffff:ffff:ffff:ffff:ffff
29261a:1c00::/24261a:1cff:ffff:ffff:ffff:ffff:ffff:ffff
30261a:1d00::/24261a:1dff:ffff:ffff:ffff:ffff:ffff:ffff
31261a:1e00::/24261a:1eff:ffff:ffff:ffff:ffff:ffff:ffff
32261a:1f00::/24261a:1fff:ffff:ffff:ffff:ffff:ffff:ffff
33261a:2000::/24261a:20ff:ffff:ffff:ffff:ffff:ffff:ffff
34261a:2100::/24261a:21ff:ffff:ffff:ffff:ffff:ffff:ffff
35261a:2200::/24261a:22ff:ffff:ffff:ffff:ffff:ffff:ffff
36261a:2300::/24261a:23ff:ffff:ffff:ffff:ffff:ffff:ffff
37261a:2400::/24261a:24ff:ffff:ffff:ffff:ffff:ffff:ffff
38261a:2500::/24261a:25ff:ffff:ffff:ffff:ffff:ffff:ffff
39261a:2600::/24261a:26ff:ffff:ffff:ffff:ffff:ffff:ffff
40261a:2700::/24261a:27ff:ffff:ffff:ffff:ffff:ffff:ffff
41261a:2800::/24261a:28ff:ffff:ffff:ffff:ffff:ffff:ffff
42261a:2900::/24261a:29ff:ffff:ffff:ffff:ffff:ffff:ffff
43261a:2a00::/24261a:2aff:ffff:ffff:ffff:ffff:ffff:ffff
44261a:2b00::/24261a:2bff:ffff:ffff:ffff:ffff:ffff:ffff
45261a:2c00::/24261a:2cff:ffff:ffff:ffff:ffff:ffff:ffff
46261a:2d00::/24261a:2dff:ffff:ffff:ffff:ffff:ffff:ffff
47261a:2e00::/24261a:2eff:ffff:ffff:ffff:ffff:ffff:ffff
48261a:2f00::/24261a:2fff:ffff:ffff:ffff:ffff:ffff:ffff
49261a:3000::/24261a:30ff:ffff:ffff:ffff:ffff:ffff:ffff
50261a:3100::/24261a:31ff:ffff:ffff:ffff:ffff:ffff:ffff
51261a:3200::/24261a:32ff:ffff:ffff:ffff:ffff:ffff:ffff
52261a:3300::/24261a:33ff:ffff:ffff:ffff:ffff:ffff:ffff
53261a:3400::/24261a:34ff:ffff:ffff:ffff:ffff:ffff:ffff
54261a:3500::/24261a:35ff:ffff:ffff:ffff:ffff:ffff:ffff
55261a:3600::/24261a:36ff:ffff:ffff:ffff:ffff:ffff:ffff
56261a:3700::/24261a:37ff:ffff:ffff:ffff:ffff:ffff:ffff
57261a:3800::/24261a:38ff:ffff:ffff:ffff:ffff:ffff:ffff
58261a:3900::/24261a:39ff:ffff:ffff:ffff:ffff:ffff:ffff
59261a:3a00::/24261a:3aff:ffff:ffff:ffff:ffff:ffff:ffff
60261a:3b00::/24261a:3bff:ffff:ffff:ffff:ffff:ffff:ffff
61261a:3c00::/24261a:3cff:ffff:ffff:ffff:ffff:ffff:ffff
62261a:3d00::/24261a:3dff:ffff:ffff:ffff:ffff:ffff:ffff
63261a:3e00::/24261a:3eff:ffff:ffff:ffff:ffff:ffff:ffff
64261a:3f00::/24261a:3fff:ffff:ffff:ffff:ffff:ffff:ffff
65261a:4000::/24261a:40ff:ffff:ffff:ffff:ffff:ffff:ffff
66261a:4100::/24261a:41ff:ffff:ffff:ffff:ffff:ffff:ffff
67261a:4200::/24261a:42ff:ffff:ffff:ffff:ffff:ffff:ffff
68261a:4300::/24261a:43ff:ffff:ffff:ffff:ffff:ffff:ffff
69261a:4400::/24261a:44ff:ffff:ffff:ffff:ffff:ffff:ffff
70261a:4500::/24261a:45ff:ffff:ffff:ffff:ffff:ffff:ffff
71261a:4600::/24261a:46ff:ffff:ffff:ffff:ffff:ffff:ffff
72261a:4700::/24261a:47ff:ffff:ffff:ffff:ffff:ffff:ffff
73261a:4800::/24261a:48ff:ffff:ffff:ffff:ffff:ffff:ffff
74261a:4900::/24261a:49ff:ffff:ffff:ffff:ffff:ffff:ffff
75261a:4a00::/24261a:4aff:ffff:ffff:ffff:ffff:ffff:ffff
76261a:4b00::/24261a:4bff:ffff:ffff:ffff:ffff:ffff:ffff
77261a:4c00::/24261a:4cff:ffff:ffff:ffff:ffff:ffff:ffff
78261a:4d00::/24261a:4dff:ffff:ffff:ffff:ffff:ffff:ffff
79261a:4e00::/24261a:4eff:ffff:ffff:ffff:ffff:ffff:ffff
80261a:4f00::/24261a:4fff:ffff:ffff:ffff:ffff:ffff:ffff
81261a:5000::/24261a:50ff:ffff:ffff:ffff:ffff:ffff:ffff
82261a:5100::/24261a:51ff:ffff:ffff:ffff:ffff:ffff:ffff
83261a:5200::/24261a:52ff:ffff:ffff:ffff:ffff:ffff:ffff
84261a:5300::/24261a:53ff:ffff:ffff:ffff:ffff:ffff:ffff
85261a:5400::/24261a:54ff:ffff:ffff:ffff:ffff:ffff:ffff
86261a:5500::/24261a:55ff:ffff:ffff:ffff:ffff:ffff:ffff
87261a:5600::/24261a:56ff:ffff:ffff:ffff:ffff:ffff:ffff
88261a:5700::/24261a:57ff:ffff:ffff:ffff:ffff:ffff:ffff
89261a:5800::/24261a:58ff:ffff:ffff:ffff:ffff:ffff:ffff
90261a:5900::/24261a:59ff:ffff:ffff:ffff:ffff:ffff:ffff
91261a:5a00::/24261a:5aff:ffff:ffff:ffff:ffff:ffff:ffff
92261a:5b00::/24261a:5bff:ffff:ffff:ffff:ffff:ffff:ffff
93261a:5c00::/24261a:5cff:ffff:ffff:ffff:ffff:ffff:ffff
94261a:5d00::/24261a:5dff:ffff:ffff:ffff:ffff:ffff:ffff
95261a:5e00::/24261a:5eff:ffff:ffff:ffff:ffff:ffff:ffff
96261a:5f00::/24261a:5fff:ffff:ffff:ffff:ffff:ffff:ffff
97261a:6000::/24261a:60ff:ffff:ffff:ffff:ffff:ffff:ffff
98261a:6100::/24261a:61ff:ffff:ffff:ffff:ffff:ffff:ffff
99261a:6200::/24261a:62ff:ffff:ffff:ffff:ffff:ffff:ffff
100261a:6300::/24261a:63ff:ffff:ffff:ffff:ffff:ffff:ffff
101261a:6400::/24261a:64ff:ffff:ffff:ffff:ffff:ffff:ffff
102261a:6500::/24261a:65ff:ffff:ffff:ffff:ffff:ffff:ffff
103261a:6600::/24261a:66ff:ffff:ffff:ffff:ffff:ffff:ffff
104261a:6700::/24261a:67ff:ffff:ffff:ffff:ffff:ffff:ffff
105261a:6800::/24261a:68ff:ffff:ffff:ffff:ffff:ffff:ffff
106261a:6900::/24261a:69ff:ffff:ffff:ffff:ffff:ffff:ffff
107261a:6a00::/24261a:6aff:ffff:ffff:ffff:ffff:ffff:ffff
108261a:6b00::/24261a:6bff:ffff:ffff:ffff:ffff:ffff:ffff
109261a:6c00::/24261a:6cff:ffff:ffff:ffff:ffff:ffff:ffff
110261a:6d00::/24261a:6dff:ffff:ffff:ffff:ffff:ffff:ffff
111261a:6e00::/24261a:6eff:ffff:ffff:ffff:ffff:ffff:ffff
112261a:6f00::/24261a:6fff:ffff:ffff:ffff:ffff:ffff:ffff
113261a:7000::/24261a:70ff:ffff:ffff:ffff:ffff:ffff:ffff
114261a:7100::/24261a:71ff:ffff:ffff:ffff:ffff:ffff:ffff
115261a:7200::/24261a:72ff:ffff:ffff:ffff:ffff:ffff:ffff
116261a:7300::/24261a:73ff:ffff:ffff:ffff:ffff:ffff:ffff
117261a:7400::/24261a:74ff:ffff:ffff:ffff:ffff:ffff:ffff
118261a:7500::/24261a:75ff:ffff:ffff:ffff:ffff:ffff:ffff
119261a:7600::/24261a:76ff:ffff:ffff:ffff:ffff:ffff:ffff
120261a:7700::/24261a:77ff:ffff:ffff:ffff:ffff:ffff:ffff
121261a:7800::/24261a:78ff:ffff:ffff:ffff:ffff:ffff:ffff
122261a:7900::/24261a:79ff:ffff:ffff:ffff:ffff:ffff:ffff
123261a:7a00::/24261a:7aff:ffff:ffff:ffff:ffff:ffff:ffff
124261a:7b00::/24261a:7bff:ffff:ffff:ffff:ffff:ffff:ffff
125261a:7c00::/24261a:7cff:ffff:ffff:ffff:ffff:ffff:ffff
126261a:7d00::/24261a:7dff:ffff:ffff:ffff:ffff:ffff:ffff
127261a:7e00::/24261a:7eff:ffff:ffff:ffff:ffff:ffff:ffff
128261a:7f00::/24261a:7fff:ffff:ffff:ffff:ffff:ffff:ffff
129261a:8000::/24261a:80ff:ffff:ffff:ffff:ffff:ffff:ffff
130261a:8100::/24261a:81ff:ffff:ffff:ffff:ffff:ffff:ffff
131261a:8200::/24261a:82ff:ffff:ffff:ffff:ffff:ffff:ffff
132261a:8300::/24261a:83ff:ffff:ffff:ffff:ffff:ffff:ffff
133261a:8400::/24261a:84ff:ffff:ffff:ffff:ffff:ffff:ffff
134261a:8500::/24261a:85ff:ffff:ffff:ffff:ffff:ffff:ffff
135261a:8600::/24261a:86ff:ffff:ffff:ffff:ffff:ffff:ffff
136261a:8700::/24261a:87ff:ffff:ffff:ffff:ffff:ffff:ffff
137261a:8800::/24261a:88ff:ffff:ffff:ffff:ffff:ffff:ffff
138261a:8900::/24261a:89ff:ffff:ffff:ffff:ffff:ffff:ffff
139261a:8a00::/24261a:8aff:ffff:ffff:ffff:ffff:ffff:ffff
140261a:8b00::/24261a:8bff:ffff:ffff:ffff:ffff:ffff:ffff
141261a:8c00::/24261a:8cff:ffff:ffff:ffff:ffff:ffff:ffff
142261a:8d00::/24261a:8dff:ffff:ffff:ffff:ffff:ffff:ffff
143261a:8e00::/24261a:8eff:ffff:ffff:ffff:ffff:ffff:ffff
144261a:8f00::/24261a:8fff:ffff:ffff:ffff:ffff:ffff:ffff
145261a:9000::/24261a:90ff:ffff:ffff:ffff:ffff:ffff:ffff
146261a:9100::/24261a:91ff:ffff:ffff:ffff:ffff:ffff:ffff
147261a:9200::/24261a:92ff:ffff:ffff:ffff:ffff:ffff:ffff
148261a:9300::/24261a:93ff:ffff:ffff:ffff:ffff:ffff:ffff
149261a:9400::/24261a:94ff:ffff:ffff:ffff:ffff:ffff:ffff
150261a:9500::/24261a:95ff:ffff:ffff:ffff:ffff:ffff:ffff
151261a:9600::/24261a:96ff:ffff:ffff:ffff:ffff:ffff:ffff
152261a:9700::/24261a:97ff:ffff:ffff:ffff:ffff:ffff:ffff
153261a:9800::/24261a:98ff:ffff:ffff:ffff:ffff:ffff:ffff
154261a:9900::/24261a:99ff:ffff:ffff:ffff:ffff:ffff:ffff
155261a:9a00::/24261a:9aff:ffff:ffff:ffff:ffff:ffff:ffff
156261a:9b00::/24261a:9bff:ffff:ffff:ffff:ffff:ffff:ffff
157261a:9c00::/24261a:9cff:ffff:ffff:ffff:ffff:ffff:ffff
158261a:9d00::/24261a:9dff:ffff:ffff:ffff:ffff:ffff:ffff
159261a:9e00::/24261a:9eff:ffff:ffff:ffff:ffff:ffff:ffff
160261a:9f00::/24261a:9fff:ffff:ffff:ffff:ffff:ffff:ffff
161261a:a000::/24261a:a0ff:ffff:ffff:ffff:ffff:ffff:ffff
162261a:a100::/24261a:a1ff:ffff:ffff:ffff:ffff:ffff:ffff
163261a:a200::/24261a:a2ff:ffff:ffff:ffff:ffff:ffff:ffff
164261a:a300::/24261a:a3ff:ffff:ffff:ffff:ffff:ffff:ffff
165261a:a400::/24261a:a4ff:ffff:ffff:ffff:ffff:ffff:ffff
166261a:a500::/24261a:a5ff:ffff:ffff:ffff:ffff:ffff:ffff
167261a:a600::/24261a:a6ff:ffff:ffff:ffff:ffff:ffff:ffff
168261a:a700::/24261a:a7ff:ffff:ffff:ffff:ffff:ffff:ffff
169261a:a800::/24261a:a8ff:ffff:ffff:ffff:ffff:ffff:ffff
170261a:a900::/24261a:a9ff:ffff:ffff:ffff:ffff:ffff:ffff
171261a:aa00::/24261a:aaff:ffff:ffff:ffff:ffff:ffff:ffff
172261a:ab00::/24261a:abff:ffff:ffff:ffff:ffff:ffff:ffff
173261a:ac00::/24261a:acff:ffff:ffff:ffff:ffff:ffff:ffff
174261a:ad00::/24261a:adff:ffff:ffff:ffff:ffff:ffff:ffff
175261a:ae00::/24261a:aeff:ffff:ffff:ffff:ffff:ffff:ffff
176261a:af00::/24261a:afff:ffff:ffff:ffff:ffff:ffff:ffff
177261a:b000::/24261a:b0ff:ffff:ffff:ffff:ffff:ffff:ffff
178261a:b100::/24261a:b1ff:ffff:ffff:ffff:ffff:ffff:ffff
179261a:b200::/24261a:b2ff:ffff:ffff:ffff:ffff:ffff:ffff
180261a:b300::/24261a:b3ff:ffff:ffff:ffff:ffff:ffff:ffff
181261a:b400::/24261a:b4ff:ffff:ffff:ffff:ffff:ffff:ffff
182261a:b500::/24261a:b5ff:ffff:ffff:ffff:ffff:ffff:ffff
183261a:b600::/24261a:b6ff:ffff:ffff:ffff:ffff:ffff:ffff
184261a:b700::/24261a:b7ff:ffff:ffff:ffff:ffff:ffff:ffff
185261a:b800::/24261a:b8ff:ffff:ffff:ffff:ffff:ffff:ffff
186261a:b900::/24261a:b9ff:ffff:ffff:ffff:ffff:ffff:ffff
187261a:ba00::/24261a:baff:ffff:ffff:ffff:ffff:ffff:ffff
188261a:bb00::/24261a:bbff:ffff:ffff:ffff:ffff:ffff:ffff
189261a:bc00::/24261a:bcff:ffff:ffff:ffff:ffff:ffff:ffff
190261a:bd00::/24261a:bdff:ffff:ffff:ffff:ffff:ffff:ffff
191261a:be00::/24261a:beff:ffff:ffff:ffff:ffff:ffff:ffff
192261a:bf00::/24261a:bfff:ffff:ffff:ffff:ffff:ffff:ffff
193261a:c000::/24261a:c0ff:ffff:ffff:ffff:ffff:ffff:ffff
194261a:c100::/24261a:c1ff:ffff:ffff:ffff:ffff:ffff:ffff
195261a:c200::/24261a:c2ff:ffff:ffff:ffff:ffff:ffff:ffff
196261a:c300::/24261a:c3ff:ffff:ffff:ffff:ffff:ffff:ffff
197261a:c400::/24261a:c4ff:ffff:ffff:ffff:ffff:ffff:ffff
198261a:c500::/24261a:c5ff:ffff:ffff:ffff:ffff:ffff:ffff
199261a:c600::/24261a:c6ff:ffff:ffff:ffff:ffff:ffff:ffff
200261a:c700::/24261a:c7ff:ffff:ffff:ffff:ffff:ffff:ffff
201261a:c800::/24261a:c8ff:ffff:ffff:ffff:ffff:ffff:ffff
202261a:c900::/24261a:c9ff:ffff:ffff:ffff:ffff:ffff:ffff
203261a:ca00::/24261a:caff:ffff:ffff:ffff:ffff:ffff:ffff
204261a:cb00::/24261a:cbff:ffff:ffff:ffff:ffff:ffff:ffff
205261a:cc00::/24261a:ccff:ffff:ffff:ffff:ffff:ffff:ffff
206261a:cd00::/24261a:cdff:ffff:ffff:ffff:ffff:ffff:ffff
207261a:ce00::/24261a:ceff:ffff:ffff:ffff:ffff:ffff:ffff
208261a:cf00::/24261a:cfff:ffff:ffff:ffff:ffff:ffff:ffff
209261a:d000::/24261a:d0ff:ffff:ffff:ffff:ffff:ffff:ffff
210261a:d100::/24261a:d1ff:ffff:ffff:ffff:ffff:ffff:ffff
211261a:d200::/24261a:d2ff:ffff:ffff:ffff:ffff:ffff:ffff
212261a:d300::/24261a:d3ff:ffff:ffff:ffff:ffff:ffff:ffff
213261a:d400::/24261a:d4ff:ffff:ffff:ffff:ffff:ffff:ffff
214261a:d500::/24261a:d5ff:ffff:ffff:ffff:ffff:ffff:ffff
215261a:d600::/24261a:d6ff:ffff:ffff:ffff:ffff:ffff:ffff
216261a:d700::/24261a:d7ff:ffff:ffff:ffff:ffff:ffff:ffff
217261a:d800::/24261a:d8ff:ffff:ffff:ffff:ffff:ffff:ffff
218261a:d900::/24261a:d9ff:ffff:ffff:ffff:ffff:ffff:ffff
219261a:da00::/24261a:daff:ffff:ffff:ffff:ffff:ffff:ffff
220261a:db00::/24261a:dbff:ffff:ffff:ffff:ffff:ffff:ffff
221261a:dc00::/24261a:dcff:ffff:ffff:ffff:ffff:ffff:ffff
222261a:dd00::/24261a:ddff:ffff:ffff:ffff:ffff:ffff:ffff
223261a:de00::/24261a:deff:ffff:ffff:ffff:ffff:ffff:ffff
224261a:df00::/24261a:dfff:ffff:ffff:ffff:ffff:ffff:ffff
225261a:e000::/24261a:e0ff:ffff:ffff:ffff:ffff:ffff:ffff
226261a:e100::/24261a:e1ff:ffff:ffff:ffff:ffff:ffff:ffff
227261a:e200::/24261a:e2ff:ffff:ffff:ffff:ffff:ffff:ffff
228261a:e300::/24261a:e3ff:ffff:ffff:ffff:ffff:ffff:ffff
229261a:e400::/24261a:e4ff:ffff:ffff:ffff:ffff:ffff:ffff
230261a:e500::/24261a:e5ff:ffff:ffff:ffff:ffff:ffff:ffff
231261a:e600::/24261a:e6ff:ffff:ffff:ffff:ffff:ffff:ffff
232261a:e700::/24261a:e7ff:ffff:ffff:ffff:ffff:ffff:ffff
233261a:e800::/24261a:e8ff:ffff:ffff:ffff:ffff:ffff:ffff
234261a:e900::/24261a:e9ff:ffff:ffff:ffff:ffff:ffff:ffff
235261a:ea00::/24261a:eaff:ffff:ffff:ffff:ffff:ffff:ffff
236261a:eb00::/24261a:ebff:ffff:ffff:ffff:ffff:ffff:ffff
237261a:ec00::/24261a:ecff:ffff:ffff:ffff:ffff:ffff:ffff
238261a:ed00::/24261a:edff:ffff:ffff:ffff:ffff:ffff:ffff
239261a:ee00::/24261a:eeff:ffff:ffff:ffff:ffff:ffff:ffff
240261a:ef00::/24261a:efff:ffff:ffff:ffff:ffff:ffff:ffff
241261a:f000::/24261a:f0ff:ffff:ffff:ffff:ffff:ffff:ffff
242261a:f100::/24261a:f1ff:ffff:ffff:ffff:ffff:ffff:ffff
243261a:f200::/24261a:f2ff:ffff:ffff:ffff:ffff:ffff:ffff
244261a:f300::/24261a:f3ff:ffff:ffff:ffff:ffff:ffff:ffff
245261a:f400::/24261a:f4ff:ffff:ffff:ffff:ffff:ffff:ffff
246261a:f500::/24261a:f5ff:ffff:ffff:ffff:ffff:ffff:ffff
247261a:f600::/24261a:f6ff:ffff:ffff:ffff:ffff:ffff:ffff
248261a:f700::/24261a:f7ff:ffff:ffff:ffff:ffff:ffff:ffff
249261a:f800::/24261a:f8ff:ffff:ffff:ffff:ffff:ffff:ffff
250261a:f900::/24261a:f9ff:ffff:ffff:ffff:ffff:ffff:ffff
251261a:fa00::/24261a:faff:ffff:ffff:ffff:ffff:ffff:ffff
252261a:fb00::/24261a:fbff:ffff:ffff:ffff:ffff:ffff:ffff
253261a:fc00::/24261a:fcff:ffff:ffff:ffff:ffff:ffff:ffff
254261a:fd00::/24261a:fdff:ffff:ffff:ffff:ffff:ffff:ffff
255261a:fe00::/24261a:feff:ffff:ffff:ffff:ffff:ffff:ffff
256261a:ff00::/24261a: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.