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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
fc38::/16
First address
fc38::
Last address
fc38: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
fc38:0000:0000:0000:0000:0000:0000:0000
Type
Unique local (ULA) fc00::/7
Private IPv6, like RFC 1918; usually fd00::/8
Reverse DNS zone
8.3.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)

fc38::/16 makes 256 subnets of /24.

Subnets
#SubnetLast address
1fc38::/24fc38:ff:ffff:ffff:ffff:ffff:ffff:ffff
2fc38:100::/24fc38:1ff:ffff:ffff:ffff:ffff:ffff:ffff
3fc38:200::/24fc38:2ff:ffff:ffff:ffff:ffff:ffff:ffff
4fc38:300::/24fc38:3ff:ffff:ffff:ffff:ffff:ffff:ffff
5fc38:400::/24fc38:4ff:ffff:ffff:ffff:ffff:ffff:ffff
6fc38:500::/24fc38:5ff:ffff:ffff:ffff:ffff:ffff:ffff
7fc38:600::/24fc38:6ff:ffff:ffff:ffff:ffff:ffff:ffff
8fc38:700::/24fc38:7ff:ffff:ffff:ffff:ffff:ffff:ffff
9fc38:800::/24fc38:8ff:ffff:ffff:ffff:ffff:ffff:ffff
10fc38:900::/24fc38:9ff:ffff:ffff:ffff:ffff:ffff:ffff
11fc38:a00::/24fc38:aff:ffff:ffff:ffff:ffff:ffff:ffff
12fc38:b00::/24fc38:bff:ffff:ffff:ffff:ffff:ffff:ffff
13fc38:c00::/24fc38:cff:ffff:ffff:ffff:ffff:ffff:ffff
14fc38:d00::/24fc38:dff:ffff:ffff:ffff:ffff:ffff:ffff
15fc38:e00::/24fc38:eff:ffff:ffff:ffff:ffff:ffff:ffff
16fc38:f00::/24fc38:fff:ffff:ffff:ffff:ffff:ffff:ffff
17fc38:1000::/24fc38:10ff:ffff:ffff:ffff:ffff:ffff:ffff
18fc38:1100::/24fc38:11ff:ffff:ffff:ffff:ffff:ffff:ffff
19fc38:1200::/24fc38:12ff:ffff:ffff:ffff:ffff:ffff:ffff
20fc38:1300::/24fc38:13ff:ffff:ffff:ffff:ffff:ffff:ffff
21fc38:1400::/24fc38:14ff:ffff:ffff:ffff:ffff:ffff:ffff
22fc38:1500::/24fc38:15ff:ffff:ffff:ffff:ffff:ffff:ffff
23fc38:1600::/24fc38:16ff:ffff:ffff:ffff:ffff:ffff:ffff
24fc38:1700::/24fc38:17ff:ffff:ffff:ffff:ffff:ffff:ffff
25fc38:1800::/24fc38:18ff:ffff:ffff:ffff:ffff:ffff:ffff
26fc38:1900::/24fc38:19ff:ffff:ffff:ffff:ffff:ffff:ffff
27fc38:1a00::/24fc38:1aff:ffff:ffff:ffff:ffff:ffff:ffff
28fc38:1b00::/24fc38:1bff:ffff:ffff:ffff:ffff:ffff:ffff
29fc38:1c00::/24fc38:1cff:ffff:ffff:ffff:ffff:ffff:ffff
30fc38:1d00::/24fc38:1dff:ffff:ffff:ffff:ffff:ffff:ffff
31fc38:1e00::/24fc38:1eff:ffff:ffff:ffff:ffff:ffff:ffff
32fc38:1f00::/24fc38:1fff:ffff:ffff:ffff:ffff:ffff:ffff
33fc38:2000::/24fc38:20ff:ffff:ffff:ffff:ffff:ffff:ffff
34fc38:2100::/24fc38:21ff:ffff:ffff:ffff:ffff:ffff:ffff
35fc38:2200::/24fc38:22ff:ffff:ffff:ffff:ffff:ffff:ffff
36fc38:2300::/24fc38:23ff:ffff:ffff:ffff:ffff:ffff:ffff
37fc38:2400::/24fc38:24ff:ffff:ffff:ffff:ffff:ffff:ffff
38fc38:2500::/24fc38:25ff:ffff:ffff:ffff:ffff:ffff:ffff
39fc38:2600::/24fc38:26ff:ffff:ffff:ffff:ffff:ffff:ffff
40fc38:2700::/24fc38:27ff:ffff:ffff:ffff:ffff:ffff:ffff
41fc38:2800::/24fc38:28ff:ffff:ffff:ffff:ffff:ffff:ffff
42fc38:2900::/24fc38:29ff:ffff:ffff:ffff:ffff:ffff:ffff
43fc38:2a00::/24fc38:2aff:ffff:ffff:ffff:ffff:ffff:ffff
44fc38:2b00::/24fc38:2bff:ffff:ffff:ffff:ffff:ffff:ffff
45fc38:2c00::/24fc38:2cff:ffff:ffff:ffff:ffff:ffff:ffff
46fc38:2d00::/24fc38:2dff:ffff:ffff:ffff:ffff:ffff:ffff
47fc38:2e00::/24fc38:2eff:ffff:ffff:ffff:ffff:ffff:ffff
48fc38:2f00::/24fc38:2fff:ffff:ffff:ffff:ffff:ffff:ffff
49fc38:3000::/24fc38:30ff:ffff:ffff:ffff:ffff:ffff:ffff
50fc38:3100::/24fc38:31ff:ffff:ffff:ffff:ffff:ffff:ffff
51fc38:3200::/24fc38:32ff:ffff:ffff:ffff:ffff:ffff:ffff
52fc38:3300::/24fc38:33ff:ffff:ffff:ffff:ffff:ffff:ffff
53fc38:3400::/24fc38:34ff:ffff:ffff:ffff:ffff:ffff:ffff
54fc38:3500::/24fc38:35ff:ffff:ffff:ffff:ffff:ffff:ffff
55fc38:3600::/24fc38:36ff:ffff:ffff:ffff:ffff:ffff:ffff
56fc38:3700::/24fc38:37ff:ffff:ffff:ffff:ffff:ffff:ffff
57fc38:3800::/24fc38:38ff:ffff:ffff:ffff:ffff:ffff:ffff
58fc38:3900::/24fc38:39ff:ffff:ffff:ffff:ffff:ffff:ffff
59fc38:3a00::/24fc38:3aff:ffff:ffff:ffff:ffff:ffff:ffff
60fc38:3b00::/24fc38:3bff:ffff:ffff:ffff:ffff:ffff:ffff
61fc38:3c00::/24fc38:3cff:ffff:ffff:ffff:ffff:ffff:ffff
62fc38:3d00::/24fc38:3dff:ffff:ffff:ffff:ffff:ffff:ffff
63fc38:3e00::/24fc38:3eff:ffff:ffff:ffff:ffff:ffff:ffff
64fc38:3f00::/24fc38:3fff:ffff:ffff:ffff:ffff:ffff:ffff
65fc38:4000::/24fc38:40ff:ffff:ffff:ffff:ffff:ffff:ffff
66fc38:4100::/24fc38:41ff:ffff:ffff:ffff:ffff:ffff:ffff
67fc38:4200::/24fc38:42ff:ffff:ffff:ffff:ffff:ffff:ffff
68fc38:4300::/24fc38:43ff:ffff:ffff:ffff:ffff:ffff:ffff
69fc38:4400::/24fc38:44ff:ffff:ffff:ffff:ffff:ffff:ffff
70fc38:4500::/24fc38:45ff:ffff:ffff:ffff:ffff:ffff:ffff
71fc38:4600::/24fc38:46ff:ffff:ffff:ffff:ffff:ffff:ffff
72fc38:4700::/24fc38:47ff:ffff:ffff:ffff:ffff:ffff:ffff
73fc38:4800::/24fc38:48ff:ffff:ffff:ffff:ffff:ffff:ffff
74fc38:4900::/24fc38:49ff:ffff:ffff:ffff:ffff:ffff:ffff
75fc38:4a00::/24fc38:4aff:ffff:ffff:ffff:ffff:ffff:ffff
76fc38:4b00::/24fc38:4bff:ffff:ffff:ffff:ffff:ffff:ffff
77fc38:4c00::/24fc38:4cff:ffff:ffff:ffff:ffff:ffff:ffff
78fc38:4d00::/24fc38:4dff:ffff:ffff:ffff:ffff:ffff:ffff
79fc38:4e00::/24fc38:4eff:ffff:ffff:ffff:ffff:ffff:ffff
80fc38:4f00::/24fc38:4fff:ffff:ffff:ffff:ffff:ffff:ffff
81fc38:5000::/24fc38:50ff:ffff:ffff:ffff:ffff:ffff:ffff
82fc38:5100::/24fc38:51ff:ffff:ffff:ffff:ffff:ffff:ffff
83fc38:5200::/24fc38:52ff:ffff:ffff:ffff:ffff:ffff:ffff
84fc38:5300::/24fc38:53ff:ffff:ffff:ffff:ffff:ffff:ffff
85fc38:5400::/24fc38:54ff:ffff:ffff:ffff:ffff:ffff:ffff
86fc38:5500::/24fc38:55ff:ffff:ffff:ffff:ffff:ffff:ffff
87fc38:5600::/24fc38:56ff:ffff:ffff:ffff:ffff:ffff:ffff
88fc38:5700::/24fc38:57ff:ffff:ffff:ffff:ffff:ffff:ffff
89fc38:5800::/24fc38:58ff:ffff:ffff:ffff:ffff:ffff:ffff
90fc38:5900::/24fc38:59ff:ffff:ffff:ffff:ffff:ffff:ffff
91fc38:5a00::/24fc38:5aff:ffff:ffff:ffff:ffff:ffff:ffff
92fc38:5b00::/24fc38:5bff:ffff:ffff:ffff:ffff:ffff:ffff
93fc38:5c00::/24fc38:5cff:ffff:ffff:ffff:ffff:ffff:ffff
94fc38:5d00::/24fc38:5dff:ffff:ffff:ffff:ffff:ffff:ffff
95fc38:5e00::/24fc38:5eff:ffff:ffff:ffff:ffff:ffff:ffff
96fc38:5f00::/24fc38:5fff:ffff:ffff:ffff:ffff:ffff:ffff
97fc38:6000::/24fc38:60ff:ffff:ffff:ffff:ffff:ffff:ffff
98fc38:6100::/24fc38:61ff:ffff:ffff:ffff:ffff:ffff:ffff
99fc38:6200::/24fc38:62ff:ffff:ffff:ffff:ffff:ffff:ffff
100fc38:6300::/24fc38:63ff:ffff:ffff:ffff:ffff:ffff:ffff
101fc38:6400::/24fc38:64ff:ffff:ffff:ffff:ffff:ffff:ffff
102fc38:6500::/24fc38:65ff:ffff:ffff:ffff:ffff:ffff:ffff
103fc38:6600::/24fc38:66ff:ffff:ffff:ffff:ffff:ffff:ffff
104fc38:6700::/24fc38:67ff:ffff:ffff:ffff:ffff:ffff:ffff
105fc38:6800::/24fc38:68ff:ffff:ffff:ffff:ffff:ffff:ffff
106fc38:6900::/24fc38:69ff:ffff:ffff:ffff:ffff:ffff:ffff
107fc38:6a00::/24fc38:6aff:ffff:ffff:ffff:ffff:ffff:ffff
108fc38:6b00::/24fc38:6bff:ffff:ffff:ffff:ffff:ffff:ffff
109fc38:6c00::/24fc38:6cff:ffff:ffff:ffff:ffff:ffff:ffff
110fc38:6d00::/24fc38:6dff:ffff:ffff:ffff:ffff:ffff:ffff
111fc38:6e00::/24fc38:6eff:ffff:ffff:ffff:ffff:ffff:ffff
112fc38:6f00::/24fc38:6fff:ffff:ffff:ffff:ffff:ffff:ffff
113fc38:7000::/24fc38:70ff:ffff:ffff:ffff:ffff:ffff:ffff
114fc38:7100::/24fc38:71ff:ffff:ffff:ffff:ffff:ffff:ffff
115fc38:7200::/24fc38:72ff:ffff:ffff:ffff:ffff:ffff:ffff
116fc38:7300::/24fc38:73ff:ffff:ffff:ffff:ffff:ffff:ffff
117fc38:7400::/24fc38:74ff:ffff:ffff:ffff:ffff:ffff:ffff
118fc38:7500::/24fc38:75ff:ffff:ffff:ffff:ffff:ffff:ffff
119fc38:7600::/24fc38:76ff:ffff:ffff:ffff:ffff:ffff:ffff
120fc38:7700::/24fc38:77ff:ffff:ffff:ffff:ffff:ffff:ffff
121fc38:7800::/24fc38:78ff:ffff:ffff:ffff:ffff:ffff:ffff
122fc38:7900::/24fc38:79ff:ffff:ffff:ffff:ffff:ffff:ffff
123fc38:7a00::/24fc38:7aff:ffff:ffff:ffff:ffff:ffff:ffff
124fc38:7b00::/24fc38:7bff:ffff:ffff:ffff:ffff:ffff:ffff
125fc38:7c00::/24fc38:7cff:ffff:ffff:ffff:ffff:ffff:ffff
126fc38:7d00::/24fc38:7dff:ffff:ffff:ffff:ffff:ffff:ffff
127fc38:7e00::/24fc38:7eff:ffff:ffff:ffff:ffff:ffff:ffff
128fc38:7f00::/24fc38:7fff:ffff:ffff:ffff:ffff:ffff:ffff
129fc38:8000::/24fc38:80ff:ffff:ffff:ffff:ffff:ffff:ffff
130fc38:8100::/24fc38:81ff:ffff:ffff:ffff:ffff:ffff:ffff
131fc38:8200::/24fc38:82ff:ffff:ffff:ffff:ffff:ffff:ffff
132fc38:8300::/24fc38:83ff:ffff:ffff:ffff:ffff:ffff:ffff
133fc38:8400::/24fc38:84ff:ffff:ffff:ffff:ffff:ffff:ffff
134fc38:8500::/24fc38:85ff:ffff:ffff:ffff:ffff:ffff:ffff
135fc38:8600::/24fc38:86ff:ffff:ffff:ffff:ffff:ffff:ffff
136fc38:8700::/24fc38:87ff:ffff:ffff:ffff:ffff:ffff:ffff
137fc38:8800::/24fc38:88ff:ffff:ffff:ffff:ffff:ffff:ffff
138fc38:8900::/24fc38:89ff:ffff:ffff:ffff:ffff:ffff:ffff
139fc38:8a00::/24fc38:8aff:ffff:ffff:ffff:ffff:ffff:ffff
140fc38:8b00::/24fc38:8bff:ffff:ffff:ffff:ffff:ffff:ffff
141fc38:8c00::/24fc38:8cff:ffff:ffff:ffff:ffff:ffff:ffff
142fc38:8d00::/24fc38:8dff:ffff:ffff:ffff:ffff:ffff:ffff
143fc38:8e00::/24fc38:8eff:ffff:ffff:ffff:ffff:ffff:ffff
144fc38:8f00::/24fc38:8fff:ffff:ffff:ffff:ffff:ffff:ffff
145fc38:9000::/24fc38:90ff:ffff:ffff:ffff:ffff:ffff:ffff
146fc38:9100::/24fc38:91ff:ffff:ffff:ffff:ffff:ffff:ffff
147fc38:9200::/24fc38:92ff:ffff:ffff:ffff:ffff:ffff:ffff
148fc38:9300::/24fc38:93ff:ffff:ffff:ffff:ffff:ffff:ffff
149fc38:9400::/24fc38:94ff:ffff:ffff:ffff:ffff:ffff:ffff
150fc38:9500::/24fc38:95ff:ffff:ffff:ffff:ffff:ffff:ffff
151fc38:9600::/24fc38:96ff:ffff:ffff:ffff:ffff:ffff:ffff
152fc38:9700::/24fc38:97ff:ffff:ffff:ffff:ffff:ffff:ffff
153fc38:9800::/24fc38:98ff:ffff:ffff:ffff:ffff:ffff:ffff
154fc38:9900::/24fc38:99ff:ffff:ffff:ffff:ffff:ffff:ffff
155fc38:9a00::/24fc38:9aff:ffff:ffff:ffff:ffff:ffff:ffff
156fc38:9b00::/24fc38:9bff:ffff:ffff:ffff:ffff:ffff:ffff
157fc38:9c00::/24fc38:9cff:ffff:ffff:ffff:ffff:ffff:ffff
158fc38:9d00::/24fc38:9dff:ffff:ffff:ffff:ffff:ffff:ffff
159fc38:9e00::/24fc38:9eff:ffff:ffff:ffff:ffff:ffff:ffff
160fc38:9f00::/24fc38:9fff:ffff:ffff:ffff:ffff:ffff:ffff
161fc38:a000::/24fc38:a0ff:ffff:ffff:ffff:ffff:ffff:ffff
162fc38:a100::/24fc38:a1ff:ffff:ffff:ffff:ffff:ffff:ffff
163fc38:a200::/24fc38:a2ff:ffff:ffff:ffff:ffff:ffff:ffff
164fc38:a300::/24fc38:a3ff:ffff:ffff:ffff:ffff:ffff:ffff
165fc38:a400::/24fc38:a4ff:ffff:ffff:ffff:ffff:ffff:ffff
166fc38:a500::/24fc38:a5ff:ffff:ffff:ffff:ffff:ffff:ffff
167fc38:a600::/24fc38:a6ff:ffff:ffff:ffff:ffff:ffff:ffff
168fc38:a700::/24fc38:a7ff:ffff:ffff:ffff:ffff:ffff:ffff
169fc38:a800::/24fc38:a8ff:ffff:ffff:ffff:ffff:ffff:ffff
170fc38:a900::/24fc38:a9ff:ffff:ffff:ffff:ffff:ffff:ffff
171fc38:aa00::/24fc38:aaff:ffff:ffff:ffff:ffff:ffff:ffff
172fc38:ab00::/24fc38:abff:ffff:ffff:ffff:ffff:ffff:ffff
173fc38:ac00::/24fc38:acff:ffff:ffff:ffff:ffff:ffff:ffff
174fc38:ad00::/24fc38:adff:ffff:ffff:ffff:ffff:ffff:ffff
175fc38:ae00::/24fc38:aeff:ffff:ffff:ffff:ffff:ffff:ffff
176fc38:af00::/24fc38:afff:ffff:ffff:ffff:ffff:ffff:ffff
177fc38:b000::/24fc38:b0ff:ffff:ffff:ffff:ffff:ffff:ffff
178fc38:b100::/24fc38:b1ff:ffff:ffff:ffff:ffff:ffff:ffff
179fc38:b200::/24fc38:b2ff:ffff:ffff:ffff:ffff:ffff:ffff
180fc38:b300::/24fc38:b3ff:ffff:ffff:ffff:ffff:ffff:ffff
181fc38:b400::/24fc38:b4ff:ffff:ffff:ffff:ffff:ffff:ffff
182fc38:b500::/24fc38:b5ff:ffff:ffff:ffff:ffff:ffff:ffff
183fc38:b600::/24fc38:b6ff:ffff:ffff:ffff:ffff:ffff:ffff
184fc38:b700::/24fc38:b7ff:ffff:ffff:ffff:ffff:ffff:ffff
185fc38:b800::/24fc38:b8ff:ffff:ffff:ffff:ffff:ffff:ffff
186fc38:b900::/24fc38:b9ff:ffff:ffff:ffff:ffff:ffff:ffff
187fc38:ba00::/24fc38:baff:ffff:ffff:ffff:ffff:ffff:ffff
188fc38:bb00::/24fc38:bbff:ffff:ffff:ffff:ffff:ffff:ffff
189fc38:bc00::/24fc38:bcff:ffff:ffff:ffff:ffff:ffff:ffff
190fc38:bd00::/24fc38:bdff:ffff:ffff:ffff:ffff:ffff:ffff
191fc38:be00::/24fc38:beff:ffff:ffff:ffff:ffff:ffff:ffff
192fc38:bf00::/24fc38:bfff:ffff:ffff:ffff:ffff:ffff:ffff
193fc38:c000::/24fc38:c0ff:ffff:ffff:ffff:ffff:ffff:ffff
194fc38:c100::/24fc38:c1ff:ffff:ffff:ffff:ffff:ffff:ffff
195fc38:c200::/24fc38:c2ff:ffff:ffff:ffff:ffff:ffff:ffff
196fc38:c300::/24fc38:c3ff:ffff:ffff:ffff:ffff:ffff:ffff
197fc38:c400::/24fc38:c4ff:ffff:ffff:ffff:ffff:ffff:ffff
198fc38:c500::/24fc38:c5ff:ffff:ffff:ffff:ffff:ffff:ffff
199fc38:c600::/24fc38:c6ff:ffff:ffff:ffff:ffff:ffff:ffff
200fc38:c700::/24fc38:c7ff:ffff:ffff:ffff:ffff:ffff:ffff
201fc38:c800::/24fc38:c8ff:ffff:ffff:ffff:ffff:ffff:ffff
202fc38:c900::/24fc38:c9ff:ffff:ffff:ffff:ffff:ffff:ffff
203fc38:ca00::/24fc38:caff:ffff:ffff:ffff:ffff:ffff:ffff
204fc38:cb00::/24fc38:cbff:ffff:ffff:ffff:ffff:ffff:ffff
205fc38:cc00::/24fc38:ccff:ffff:ffff:ffff:ffff:ffff:ffff
206fc38:cd00::/24fc38:cdff:ffff:ffff:ffff:ffff:ffff:ffff
207fc38:ce00::/24fc38:ceff:ffff:ffff:ffff:ffff:ffff:ffff
208fc38:cf00::/24fc38:cfff:ffff:ffff:ffff:ffff:ffff:ffff
209fc38:d000::/24fc38:d0ff:ffff:ffff:ffff:ffff:ffff:ffff
210fc38:d100::/24fc38:d1ff:ffff:ffff:ffff:ffff:ffff:ffff
211fc38:d200::/24fc38:d2ff:ffff:ffff:ffff:ffff:ffff:ffff
212fc38:d300::/24fc38:d3ff:ffff:ffff:ffff:ffff:ffff:ffff
213fc38:d400::/24fc38:d4ff:ffff:ffff:ffff:ffff:ffff:ffff
214fc38:d500::/24fc38:d5ff:ffff:ffff:ffff:ffff:ffff:ffff
215fc38:d600::/24fc38:d6ff:ffff:ffff:ffff:ffff:ffff:ffff
216fc38:d700::/24fc38:d7ff:ffff:ffff:ffff:ffff:ffff:ffff
217fc38:d800::/24fc38:d8ff:ffff:ffff:ffff:ffff:ffff:ffff
218fc38:d900::/24fc38:d9ff:ffff:ffff:ffff:ffff:ffff:ffff
219fc38:da00::/24fc38:daff:ffff:ffff:ffff:ffff:ffff:ffff
220fc38:db00::/24fc38:dbff:ffff:ffff:ffff:ffff:ffff:ffff
221fc38:dc00::/24fc38:dcff:ffff:ffff:ffff:ffff:ffff:ffff
222fc38:dd00::/24fc38:ddff:ffff:ffff:ffff:ffff:ffff:ffff
223fc38:de00::/24fc38:deff:ffff:ffff:ffff:ffff:ffff:ffff
224fc38:df00::/24fc38:dfff:ffff:ffff:ffff:ffff:ffff:ffff
225fc38:e000::/24fc38:e0ff:ffff:ffff:ffff:ffff:ffff:ffff
226fc38:e100::/24fc38:e1ff:ffff:ffff:ffff:ffff:ffff:ffff
227fc38:e200::/24fc38:e2ff:ffff:ffff:ffff:ffff:ffff:ffff
228fc38:e300::/24fc38:e3ff:ffff:ffff:ffff:ffff:ffff:ffff
229fc38:e400::/24fc38:e4ff:ffff:ffff:ffff:ffff:ffff:ffff
230fc38:e500::/24fc38:e5ff:ffff:ffff:ffff:ffff:ffff:ffff
231fc38:e600::/24fc38:e6ff:ffff:ffff:ffff:ffff:ffff:ffff
232fc38:e700::/24fc38:e7ff:ffff:ffff:ffff:ffff:ffff:ffff
233fc38:e800::/24fc38:e8ff:ffff:ffff:ffff:ffff:ffff:ffff
234fc38:e900::/24fc38:e9ff:ffff:ffff:ffff:ffff:ffff:ffff
235fc38:ea00::/24fc38:eaff:ffff:ffff:ffff:ffff:ffff:ffff
236fc38:eb00::/24fc38:ebff:ffff:ffff:ffff:ffff:ffff:ffff
237fc38:ec00::/24fc38:ecff:ffff:ffff:ffff:ffff:ffff:ffff
238fc38:ed00::/24fc38:edff:ffff:ffff:ffff:ffff:ffff:ffff
239fc38:ee00::/24fc38:eeff:ffff:ffff:ffff:ffff:ffff:ffff
240fc38:ef00::/24fc38:efff:ffff:ffff:ffff:ffff:ffff:ffff
241fc38:f000::/24fc38:f0ff:ffff:ffff:ffff:ffff:ffff:ffff
242fc38:f100::/24fc38:f1ff:ffff:ffff:ffff:ffff:ffff:ffff
243fc38:f200::/24fc38:f2ff:ffff:ffff:ffff:ffff:ffff:ffff
244fc38:f300::/24fc38:f3ff:ffff:ffff:ffff:ffff:ffff:ffff
245fc38:f400::/24fc38:f4ff:ffff:ffff:ffff:ffff:ffff:ffff
246fc38:f500::/24fc38:f5ff:ffff:ffff:ffff:ffff:ffff:ffff
247fc38:f600::/24fc38:f6ff:ffff:ffff:ffff:ffff:ffff:ffff
248fc38:f700::/24fc38:f7ff:ffff:ffff:ffff:ffff:ffff:ffff
249fc38:f800::/24fc38:f8ff:ffff:ffff:ffff:ffff:ffff:ffff
250fc38:f900::/24fc38:f9ff:ffff:ffff:ffff:ffff:ffff:ffff
251fc38:fa00::/24fc38:faff:ffff:ffff:ffff:ffff:ffff:ffff
252fc38:fb00::/24fc38:fbff:ffff:ffff:ffff:ffff:ffff:ffff
253fc38:fc00::/24fc38:fcff:ffff:ffff:ffff:ffff:ffff:ffff
254fc38:fd00::/24fc38:fdff:ffff:ffff:ffff:ffff:ffff:ffff
255fc38:fe00::/24fc38:feff:ffff:ffff:ffff:ffff:ffff:ffff
256fc38:ff00::/24fc38: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.