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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
fc23::/16
First address
fc23::
Last address
fc23: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
fc23:0000:0000:0000:0000:0000:0000:0000
Type
Unique local (ULA) fc00::/7
Private IPv6, like RFC 1918; usually fd00::/8
Reverse DNS zone
3.2.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)

fc23::/16 makes 256 subnets of /24.

Subnets
#SubnetLast address
1fc23::/24fc23:ff:ffff:ffff:ffff:ffff:ffff:ffff
2fc23:100::/24fc23:1ff:ffff:ffff:ffff:ffff:ffff:ffff
3fc23:200::/24fc23:2ff:ffff:ffff:ffff:ffff:ffff:ffff
4fc23:300::/24fc23:3ff:ffff:ffff:ffff:ffff:ffff:ffff
5fc23:400::/24fc23:4ff:ffff:ffff:ffff:ffff:ffff:ffff
6fc23:500::/24fc23:5ff:ffff:ffff:ffff:ffff:ffff:ffff
7fc23:600::/24fc23:6ff:ffff:ffff:ffff:ffff:ffff:ffff
8fc23:700::/24fc23:7ff:ffff:ffff:ffff:ffff:ffff:ffff
9fc23:800::/24fc23:8ff:ffff:ffff:ffff:ffff:ffff:ffff
10fc23:900::/24fc23:9ff:ffff:ffff:ffff:ffff:ffff:ffff
11fc23:a00::/24fc23:aff:ffff:ffff:ffff:ffff:ffff:ffff
12fc23:b00::/24fc23:bff:ffff:ffff:ffff:ffff:ffff:ffff
13fc23:c00::/24fc23:cff:ffff:ffff:ffff:ffff:ffff:ffff
14fc23:d00::/24fc23:dff:ffff:ffff:ffff:ffff:ffff:ffff
15fc23:e00::/24fc23:eff:ffff:ffff:ffff:ffff:ffff:ffff
16fc23:f00::/24fc23:fff:ffff:ffff:ffff:ffff:ffff:ffff
17fc23:1000::/24fc23:10ff:ffff:ffff:ffff:ffff:ffff:ffff
18fc23:1100::/24fc23:11ff:ffff:ffff:ffff:ffff:ffff:ffff
19fc23:1200::/24fc23:12ff:ffff:ffff:ffff:ffff:ffff:ffff
20fc23:1300::/24fc23:13ff:ffff:ffff:ffff:ffff:ffff:ffff
21fc23:1400::/24fc23:14ff:ffff:ffff:ffff:ffff:ffff:ffff
22fc23:1500::/24fc23:15ff:ffff:ffff:ffff:ffff:ffff:ffff
23fc23:1600::/24fc23:16ff:ffff:ffff:ffff:ffff:ffff:ffff
24fc23:1700::/24fc23:17ff:ffff:ffff:ffff:ffff:ffff:ffff
25fc23:1800::/24fc23:18ff:ffff:ffff:ffff:ffff:ffff:ffff
26fc23:1900::/24fc23:19ff:ffff:ffff:ffff:ffff:ffff:ffff
27fc23:1a00::/24fc23:1aff:ffff:ffff:ffff:ffff:ffff:ffff
28fc23:1b00::/24fc23:1bff:ffff:ffff:ffff:ffff:ffff:ffff
29fc23:1c00::/24fc23:1cff:ffff:ffff:ffff:ffff:ffff:ffff
30fc23:1d00::/24fc23:1dff:ffff:ffff:ffff:ffff:ffff:ffff
31fc23:1e00::/24fc23:1eff:ffff:ffff:ffff:ffff:ffff:ffff
32fc23:1f00::/24fc23:1fff:ffff:ffff:ffff:ffff:ffff:ffff
33fc23:2000::/24fc23:20ff:ffff:ffff:ffff:ffff:ffff:ffff
34fc23:2100::/24fc23:21ff:ffff:ffff:ffff:ffff:ffff:ffff
35fc23:2200::/24fc23:22ff:ffff:ffff:ffff:ffff:ffff:ffff
36fc23:2300::/24fc23:23ff:ffff:ffff:ffff:ffff:ffff:ffff
37fc23:2400::/24fc23:24ff:ffff:ffff:ffff:ffff:ffff:ffff
38fc23:2500::/24fc23:25ff:ffff:ffff:ffff:ffff:ffff:ffff
39fc23:2600::/24fc23:26ff:ffff:ffff:ffff:ffff:ffff:ffff
40fc23:2700::/24fc23:27ff:ffff:ffff:ffff:ffff:ffff:ffff
41fc23:2800::/24fc23:28ff:ffff:ffff:ffff:ffff:ffff:ffff
42fc23:2900::/24fc23:29ff:ffff:ffff:ffff:ffff:ffff:ffff
43fc23:2a00::/24fc23:2aff:ffff:ffff:ffff:ffff:ffff:ffff
44fc23:2b00::/24fc23:2bff:ffff:ffff:ffff:ffff:ffff:ffff
45fc23:2c00::/24fc23:2cff:ffff:ffff:ffff:ffff:ffff:ffff
46fc23:2d00::/24fc23:2dff:ffff:ffff:ffff:ffff:ffff:ffff
47fc23:2e00::/24fc23:2eff:ffff:ffff:ffff:ffff:ffff:ffff
48fc23:2f00::/24fc23:2fff:ffff:ffff:ffff:ffff:ffff:ffff
49fc23:3000::/24fc23:30ff:ffff:ffff:ffff:ffff:ffff:ffff
50fc23:3100::/24fc23:31ff:ffff:ffff:ffff:ffff:ffff:ffff
51fc23:3200::/24fc23:32ff:ffff:ffff:ffff:ffff:ffff:ffff
52fc23:3300::/24fc23:33ff:ffff:ffff:ffff:ffff:ffff:ffff
53fc23:3400::/24fc23:34ff:ffff:ffff:ffff:ffff:ffff:ffff
54fc23:3500::/24fc23:35ff:ffff:ffff:ffff:ffff:ffff:ffff
55fc23:3600::/24fc23:36ff:ffff:ffff:ffff:ffff:ffff:ffff
56fc23:3700::/24fc23:37ff:ffff:ffff:ffff:ffff:ffff:ffff
57fc23:3800::/24fc23:38ff:ffff:ffff:ffff:ffff:ffff:ffff
58fc23:3900::/24fc23:39ff:ffff:ffff:ffff:ffff:ffff:ffff
59fc23:3a00::/24fc23:3aff:ffff:ffff:ffff:ffff:ffff:ffff
60fc23:3b00::/24fc23:3bff:ffff:ffff:ffff:ffff:ffff:ffff
61fc23:3c00::/24fc23:3cff:ffff:ffff:ffff:ffff:ffff:ffff
62fc23:3d00::/24fc23:3dff:ffff:ffff:ffff:ffff:ffff:ffff
63fc23:3e00::/24fc23:3eff:ffff:ffff:ffff:ffff:ffff:ffff
64fc23:3f00::/24fc23:3fff:ffff:ffff:ffff:ffff:ffff:ffff
65fc23:4000::/24fc23:40ff:ffff:ffff:ffff:ffff:ffff:ffff
66fc23:4100::/24fc23:41ff:ffff:ffff:ffff:ffff:ffff:ffff
67fc23:4200::/24fc23:42ff:ffff:ffff:ffff:ffff:ffff:ffff
68fc23:4300::/24fc23:43ff:ffff:ffff:ffff:ffff:ffff:ffff
69fc23:4400::/24fc23:44ff:ffff:ffff:ffff:ffff:ffff:ffff
70fc23:4500::/24fc23:45ff:ffff:ffff:ffff:ffff:ffff:ffff
71fc23:4600::/24fc23:46ff:ffff:ffff:ffff:ffff:ffff:ffff
72fc23:4700::/24fc23:47ff:ffff:ffff:ffff:ffff:ffff:ffff
73fc23:4800::/24fc23:48ff:ffff:ffff:ffff:ffff:ffff:ffff
74fc23:4900::/24fc23:49ff:ffff:ffff:ffff:ffff:ffff:ffff
75fc23:4a00::/24fc23:4aff:ffff:ffff:ffff:ffff:ffff:ffff
76fc23:4b00::/24fc23:4bff:ffff:ffff:ffff:ffff:ffff:ffff
77fc23:4c00::/24fc23:4cff:ffff:ffff:ffff:ffff:ffff:ffff
78fc23:4d00::/24fc23:4dff:ffff:ffff:ffff:ffff:ffff:ffff
79fc23:4e00::/24fc23:4eff:ffff:ffff:ffff:ffff:ffff:ffff
80fc23:4f00::/24fc23:4fff:ffff:ffff:ffff:ffff:ffff:ffff
81fc23:5000::/24fc23:50ff:ffff:ffff:ffff:ffff:ffff:ffff
82fc23:5100::/24fc23:51ff:ffff:ffff:ffff:ffff:ffff:ffff
83fc23:5200::/24fc23:52ff:ffff:ffff:ffff:ffff:ffff:ffff
84fc23:5300::/24fc23:53ff:ffff:ffff:ffff:ffff:ffff:ffff
85fc23:5400::/24fc23:54ff:ffff:ffff:ffff:ffff:ffff:ffff
86fc23:5500::/24fc23:55ff:ffff:ffff:ffff:ffff:ffff:ffff
87fc23:5600::/24fc23:56ff:ffff:ffff:ffff:ffff:ffff:ffff
88fc23:5700::/24fc23:57ff:ffff:ffff:ffff:ffff:ffff:ffff
89fc23:5800::/24fc23:58ff:ffff:ffff:ffff:ffff:ffff:ffff
90fc23:5900::/24fc23:59ff:ffff:ffff:ffff:ffff:ffff:ffff
91fc23:5a00::/24fc23:5aff:ffff:ffff:ffff:ffff:ffff:ffff
92fc23:5b00::/24fc23:5bff:ffff:ffff:ffff:ffff:ffff:ffff
93fc23:5c00::/24fc23:5cff:ffff:ffff:ffff:ffff:ffff:ffff
94fc23:5d00::/24fc23:5dff:ffff:ffff:ffff:ffff:ffff:ffff
95fc23:5e00::/24fc23:5eff:ffff:ffff:ffff:ffff:ffff:ffff
96fc23:5f00::/24fc23:5fff:ffff:ffff:ffff:ffff:ffff:ffff
97fc23:6000::/24fc23:60ff:ffff:ffff:ffff:ffff:ffff:ffff
98fc23:6100::/24fc23:61ff:ffff:ffff:ffff:ffff:ffff:ffff
99fc23:6200::/24fc23:62ff:ffff:ffff:ffff:ffff:ffff:ffff
100fc23:6300::/24fc23:63ff:ffff:ffff:ffff:ffff:ffff:ffff
101fc23:6400::/24fc23:64ff:ffff:ffff:ffff:ffff:ffff:ffff
102fc23:6500::/24fc23:65ff:ffff:ffff:ffff:ffff:ffff:ffff
103fc23:6600::/24fc23:66ff:ffff:ffff:ffff:ffff:ffff:ffff
104fc23:6700::/24fc23:67ff:ffff:ffff:ffff:ffff:ffff:ffff
105fc23:6800::/24fc23:68ff:ffff:ffff:ffff:ffff:ffff:ffff
106fc23:6900::/24fc23:69ff:ffff:ffff:ffff:ffff:ffff:ffff
107fc23:6a00::/24fc23:6aff:ffff:ffff:ffff:ffff:ffff:ffff
108fc23:6b00::/24fc23:6bff:ffff:ffff:ffff:ffff:ffff:ffff
109fc23:6c00::/24fc23:6cff:ffff:ffff:ffff:ffff:ffff:ffff
110fc23:6d00::/24fc23:6dff:ffff:ffff:ffff:ffff:ffff:ffff
111fc23:6e00::/24fc23:6eff:ffff:ffff:ffff:ffff:ffff:ffff
112fc23:6f00::/24fc23:6fff:ffff:ffff:ffff:ffff:ffff:ffff
113fc23:7000::/24fc23:70ff:ffff:ffff:ffff:ffff:ffff:ffff
114fc23:7100::/24fc23:71ff:ffff:ffff:ffff:ffff:ffff:ffff
115fc23:7200::/24fc23:72ff:ffff:ffff:ffff:ffff:ffff:ffff
116fc23:7300::/24fc23:73ff:ffff:ffff:ffff:ffff:ffff:ffff
117fc23:7400::/24fc23:74ff:ffff:ffff:ffff:ffff:ffff:ffff
118fc23:7500::/24fc23:75ff:ffff:ffff:ffff:ffff:ffff:ffff
119fc23:7600::/24fc23:76ff:ffff:ffff:ffff:ffff:ffff:ffff
120fc23:7700::/24fc23:77ff:ffff:ffff:ffff:ffff:ffff:ffff
121fc23:7800::/24fc23:78ff:ffff:ffff:ffff:ffff:ffff:ffff
122fc23:7900::/24fc23:79ff:ffff:ffff:ffff:ffff:ffff:ffff
123fc23:7a00::/24fc23:7aff:ffff:ffff:ffff:ffff:ffff:ffff
124fc23:7b00::/24fc23:7bff:ffff:ffff:ffff:ffff:ffff:ffff
125fc23:7c00::/24fc23:7cff:ffff:ffff:ffff:ffff:ffff:ffff
126fc23:7d00::/24fc23:7dff:ffff:ffff:ffff:ffff:ffff:ffff
127fc23:7e00::/24fc23:7eff:ffff:ffff:ffff:ffff:ffff:ffff
128fc23:7f00::/24fc23:7fff:ffff:ffff:ffff:ffff:ffff:ffff
129fc23:8000::/24fc23:80ff:ffff:ffff:ffff:ffff:ffff:ffff
130fc23:8100::/24fc23:81ff:ffff:ffff:ffff:ffff:ffff:ffff
131fc23:8200::/24fc23:82ff:ffff:ffff:ffff:ffff:ffff:ffff
132fc23:8300::/24fc23:83ff:ffff:ffff:ffff:ffff:ffff:ffff
133fc23:8400::/24fc23:84ff:ffff:ffff:ffff:ffff:ffff:ffff
134fc23:8500::/24fc23:85ff:ffff:ffff:ffff:ffff:ffff:ffff
135fc23:8600::/24fc23:86ff:ffff:ffff:ffff:ffff:ffff:ffff
136fc23:8700::/24fc23:87ff:ffff:ffff:ffff:ffff:ffff:ffff
137fc23:8800::/24fc23:88ff:ffff:ffff:ffff:ffff:ffff:ffff
138fc23:8900::/24fc23:89ff:ffff:ffff:ffff:ffff:ffff:ffff
139fc23:8a00::/24fc23:8aff:ffff:ffff:ffff:ffff:ffff:ffff
140fc23:8b00::/24fc23:8bff:ffff:ffff:ffff:ffff:ffff:ffff
141fc23:8c00::/24fc23:8cff:ffff:ffff:ffff:ffff:ffff:ffff
142fc23:8d00::/24fc23:8dff:ffff:ffff:ffff:ffff:ffff:ffff
143fc23:8e00::/24fc23:8eff:ffff:ffff:ffff:ffff:ffff:ffff
144fc23:8f00::/24fc23:8fff:ffff:ffff:ffff:ffff:ffff:ffff
145fc23:9000::/24fc23:90ff:ffff:ffff:ffff:ffff:ffff:ffff
146fc23:9100::/24fc23:91ff:ffff:ffff:ffff:ffff:ffff:ffff
147fc23:9200::/24fc23:92ff:ffff:ffff:ffff:ffff:ffff:ffff
148fc23:9300::/24fc23:93ff:ffff:ffff:ffff:ffff:ffff:ffff
149fc23:9400::/24fc23:94ff:ffff:ffff:ffff:ffff:ffff:ffff
150fc23:9500::/24fc23:95ff:ffff:ffff:ffff:ffff:ffff:ffff
151fc23:9600::/24fc23:96ff:ffff:ffff:ffff:ffff:ffff:ffff
152fc23:9700::/24fc23:97ff:ffff:ffff:ffff:ffff:ffff:ffff
153fc23:9800::/24fc23:98ff:ffff:ffff:ffff:ffff:ffff:ffff
154fc23:9900::/24fc23:99ff:ffff:ffff:ffff:ffff:ffff:ffff
155fc23:9a00::/24fc23:9aff:ffff:ffff:ffff:ffff:ffff:ffff
156fc23:9b00::/24fc23:9bff:ffff:ffff:ffff:ffff:ffff:ffff
157fc23:9c00::/24fc23:9cff:ffff:ffff:ffff:ffff:ffff:ffff
158fc23:9d00::/24fc23:9dff:ffff:ffff:ffff:ffff:ffff:ffff
159fc23:9e00::/24fc23:9eff:ffff:ffff:ffff:ffff:ffff:ffff
160fc23:9f00::/24fc23:9fff:ffff:ffff:ffff:ffff:ffff:ffff
161fc23:a000::/24fc23:a0ff:ffff:ffff:ffff:ffff:ffff:ffff
162fc23:a100::/24fc23:a1ff:ffff:ffff:ffff:ffff:ffff:ffff
163fc23:a200::/24fc23:a2ff:ffff:ffff:ffff:ffff:ffff:ffff
164fc23:a300::/24fc23:a3ff:ffff:ffff:ffff:ffff:ffff:ffff
165fc23:a400::/24fc23:a4ff:ffff:ffff:ffff:ffff:ffff:ffff
166fc23:a500::/24fc23:a5ff:ffff:ffff:ffff:ffff:ffff:ffff
167fc23:a600::/24fc23:a6ff:ffff:ffff:ffff:ffff:ffff:ffff
168fc23:a700::/24fc23:a7ff:ffff:ffff:ffff:ffff:ffff:ffff
169fc23:a800::/24fc23:a8ff:ffff:ffff:ffff:ffff:ffff:ffff
170fc23:a900::/24fc23:a9ff:ffff:ffff:ffff:ffff:ffff:ffff
171fc23:aa00::/24fc23:aaff:ffff:ffff:ffff:ffff:ffff:ffff
172fc23:ab00::/24fc23:abff:ffff:ffff:ffff:ffff:ffff:ffff
173fc23:ac00::/24fc23:acff:ffff:ffff:ffff:ffff:ffff:ffff
174fc23:ad00::/24fc23:adff:ffff:ffff:ffff:ffff:ffff:ffff
175fc23:ae00::/24fc23:aeff:ffff:ffff:ffff:ffff:ffff:ffff
176fc23:af00::/24fc23:afff:ffff:ffff:ffff:ffff:ffff:ffff
177fc23:b000::/24fc23:b0ff:ffff:ffff:ffff:ffff:ffff:ffff
178fc23:b100::/24fc23:b1ff:ffff:ffff:ffff:ffff:ffff:ffff
179fc23:b200::/24fc23:b2ff:ffff:ffff:ffff:ffff:ffff:ffff
180fc23:b300::/24fc23:b3ff:ffff:ffff:ffff:ffff:ffff:ffff
181fc23:b400::/24fc23:b4ff:ffff:ffff:ffff:ffff:ffff:ffff
182fc23:b500::/24fc23:b5ff:ffff:ffff:ffff:ffff:ffff:ffff
183fc23:b600::/24fc23:b6ff:ffff:ffff:ffff:ffff:ffff:ffff
184fc23:b700::/24fc23:b7ff:ffff:ffff:ffff:ffff:ffff:ffff
185fc23:b800::/24fc23:b8ff:ffff:ffff:ffff:ffff:ffff:ffff
186fc23:b900::/24fc23:b9ff:ffff:ffff:ffff:ffff:ffff:ffff
187fc23:ba00::/24fc23:baff:ffff:ffff:ffff:ffff:ffff:ffff
188fc23:bb00::/24fc23:bbff:ffff:ffff:ffff:ffff:ffff:ffff
189fc23:bc00::/24fc23:bcff:ffff:ffff:ffff:ffff:ffff:ffff
190fc23:bd00::/24fc23:bdff:ffff:ffff:ffff:ffff:ffff:ffff
191fc23:be00::/24fc23:beff:ffff:ffff:ffff:ffff:ffff:ffff
192fc23:bf00::/24fc23:bfff:ffff:ffff:ffff:ffff:ffff:ffff
193fc23:c000::/24fc23:c0ff:ffff:ffff:ffff:ffff:ffff:ffff
194fc23:c100::/24fc23:c1ff:ffff:ffff:ffff:ffff:ffff:ffff
195fc23:c200::/24fc23:c2ff:ffff:ffff:ffff:ffff:ffff:ffff
196fc23:c300::/24fc23:c3ff:ffff:ffff:ffff:ffff:ffff:ffff
197fc23:c400::/24fc23:c4ff:ffff:ffff:ffff:ffff:ffff:ffff
198fc23:c500::/24fc23:c5ff:ffff:ffff:ffff:ffff:ffff:ffff
199fc23:c600::/24fc23:c6ff:ffff:ffff:ffff:ffff:ffff:ffff
200fc23:c700::/24fc23:c7ff:ffff:ffff:ffff:ffff:ffff:ffff
201fc23:c800::/24fc23:c8ff:ffff:ffff:ffff:ffff:ffff:ffff
202fc23:c900::/24fc23:c9ff:ffff:ffff:ffff:ffff:ffff:ffff
203fc23:ca00::/24fc23:caff:ffff:ffff:ffff:ffff:ffff:ffff
204fc23:cb00::/24fc23:cbff:ffff:ffff:ffff:ffff:ffff:ffff
205fc23:cc00::/24fc23:ccff:ffff:ffff:ffff:ffff:ffff:ffff
206fc23:cd00::/24fc23:cdff:ffff:ffff:ffff:ffff:ffff:ffff
207fc23:ce00::/24fc23:ceff:ffff:ffff:ffff:ffff:ffff:ffff
208fc23:cf00::/24fc23:cfff:ffff:ffff:ffff:ffff:ffff:ffff
209fc23:d000::/24fc23:d0ff:ffff:ffff:ffff:ffff:ffff:ffff
210fc23:d100::/24fc23:d1ff:ffff:ffff:ffff:ffff:ffff:ffff
211fc23:d200::/24fc23:d2ff:ffff:ffff:ffff:ffff:ffff:ffff
212fc23:d300::/24fc23:d3ff:ffff:ffff:ffff:ffff:ffff:ffff
213fc23:d400::/24fc23:d4ff:ffff:ffff:ffff:ffff:ffff:ffff
214fc23:d500::/24fc23:d5ff:ffff:ffff:ffff:ffff:ffff:ffff
215fc23:d600::/24fc23:d6ff:ffff:ffff:ffff:ffff:ffff:ffff
216fc23:d700::/24fc23:d7ff:ffff:ffff:ffff:ffff:ffff:ffff
217fc23:d800::/24fc23:d8ff:ffff:ffff:ffff:ffff:ffff:ffff
218fc23:d900::/24fc23:d9ff:ffff:ffff:ffff:ffff:ffff:ffff
219fc23:da00::/24fc23:daff:ffff:ffff:ffff:ffff:ffff:ffff
220fc23:db00::/24fc23:dbff:ffff:ffff:ffff:ffff:ffff:ffff
221fc23:dc00::/24fc23:dcff:ffff:ffff:ffff:ffff:ffff:ffff
222fc23:dd00::/24fc23:ddff:ffff:ffff:ffff:ffff:ffff:ffff
223fc23:de00::/24fc23:deff:ffff:ffff:ffff:ffff:ffff:ffff
224fc23:df00::/24fc23:dfff:ffff:ffff:ffff:ffff:ffff:ffff
225fc23:e000::/24fc23:e0ff:ffff:ffff:ffff:ffff:ffff:ffff
226fc23:e100::/24fc23:e1ff:ffff:ffff:ffff:ffff:ffff:ffff
227fc23:e200::/24fc23:e2ff:ffff:ffff:ffff:ffff:ffff:ffff
228fc23:e300::/24fc23:e3ff:ffff:ffff:ffff:ffff:ffff:ffff
229fc23:e400::/24fc23:e4ff:ffff:ffff:ffff:ffff:ffff:ffff
230fc23:e500::/24fc23:e5ff:ffff:ffff:ffff:ffff:ffff:ffff
231fc23:e600::/24fc23:e6ff:ffff:ffff:ffff:ffff:ffff:ffff
232fc23:e700::/24fc23:e7ff:ffff:ffff:ffff:ffff:ffff:ffff
233fc23:e800::/24fc23:e8ff:ffff:ffff:ffff:ffff:ffff:ffff
234fc23:e900::/24fc23:e9ff:ffff:ffff:ffff:ffff:ffff:ffff
235fc23:ea00::/24fc23:eaff:ffff:ffff:ffff:ffff:ffff:ffff
236fc23:eb00::/24fc23:ebff:ffff:ffff:ffff:ffff:ffff:ffff
237fc23:ec00::/24fc23:ecff:ffff:ffff:ffff:ffff:ffff:ffff
238fc23:ed00::/24fc23:edff:ffff:ffff:ffff:ffff:ffff:ffff
239fc23:ee00::/24fc23:eeff:ffff:ffff:ffff:ffff:ffff:ffff
240fc23:ef00::/24fc23:efff:ffff:ffff:ffff:ffff:ffff:ffff
241fc23:f000::/24fc23:f0ff:ffff:ffff:ffff:ffff:ffff:ffff
242fc23:f100::/24fc23:f1ff:ffff:ffff:ffff:ffff:ffff:ffff
243fc23:f200::/24fc23:f2ff:ffff:ffff:ffff:ffff:ffff:ffff
244fc23:f300::/24fc23:f3ff:ffff:ffff:ffff:ffff:ffff:ffff
245fc23:f400::/24fc23:f4ff:ffff:ffff:ffff:ffff:ffff:ffff
246fc23:f500::/24fc23:f5ff:ffff:ffff:ffff:ffff:ffff:ffff
247fc23:f600::/24fc23:f6ff:ffff:ffff:ffff:ffff:ffff:ffff
248fc23:f700::/24fc23:f7ff:ffff:ffff:ffff:ffff:ffff:ffff
249fc23:f800::/24fc23:f8ff:ffff:ffff:ffff:ffff:ffff:ffff
250fc23:f900::/24fc23:f9ff:ffff:ffff:ffff:ffff:ffff:ffff
251fc23:fa00::/24fc23:faff:ffff:ffff:ffff:ffff:ffff:ffff
252fc23:fb00::/24fc23:fbff:ffff:ffff:ffff:ffff:ffff:ffff
253fc23:fc00::/24fc23:fcff:ffff:ffff:ffff:ffff:ffff:ffff
254fc23:fd00::/24fc23:fdff:ffff:ffff:ffff:ffff:ffff:ffff
255fc23:fe00::/24fc23:feff:ffff:ffff:ffff:ffff:ffff:ffff
256fc23:ff00::/24fc23: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.