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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
fc3b::/16
First address
fc3b::
Last address
fc3b: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
fc3b: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.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)

fc3b::/16 makes 256 subnets of /24.

Subnets
#SubnetLast address
1fc3b::/24fc3b:ff:ffff:ffff:ffff:ffff:ffff:ffff
2fc3b:100::/24fc3b:1ff:ffff:ffff:ffff:ffff:ffff:ffff
3fc3b:200::/24fc3b:2ff:ffff:ffff:ffff:ffff:ffff:ffff
4fc3b:300::/24fc3b:3ff:ffff:ffff:ffff:ffff:ffff:ffff
5fc3b:400::/24fc3b:4ff:ffff:ffff:ffff:ffff:ffff:ffff
6fc3b:500::/24fc3b:5ff:ffff:ffff:ffff:ffff:ffff:ffff
7fc3b:600::/24fc3b:6ff:ffff:ffff:ffff:ffff:ffff:ffff
8fc3b:700::/24fc3b:7ff:ffff:ffff:ffff:ffff:ffff:ffff
9fc3b:800::/24fc3b:8ff:ffff:ffff:ffff:ffff:ffff:ffff
10fc3b:900::/24fc3b:9ff:ffff:ffff:ffff:ffff:ffff:ffff
11fc3b:a00::/24fc3b:aff:ffff:ffff:ffff:ffff:ffff:ffff
12fc3b:b00::/24fc3b:bff:ffff:ffff:ffff:ffff:ffff:ffff
13fc3b:c00::/24fc3b:cff:ffff:ffff:ffff:ffff:ffff:ffff
14fc3b:d00::/24fc3b:dff:ffff:ffff:ffff:ffff:ffff:ffff
15fc3b:e00::/24fc3b:eff:ffff:ffff:ffff:ffff:ffff:ffff
16fc3b:f00::/24fc3b:fff:ffff:ffff:ffff:ffff:ffff:ffff
17fc3b:1000::/24fc3b:10ff:ffff:ffff:ffff:ffff:ffff:ffff
18fc3b:1100::/24fc3b:11ff:ffff:ffff:ffff:ffff:ffff:ffff
19fc3b:1200::/24fc3b:12ff:ffff:ffff:ffff:ffff:ffff:ffff
20fc3b:1300::/24fc3b:13ff:ffff:ffff:ffff:ffff:ffff:ffff
21fc3b:1400::/24fc3b:14ff:ffff:ffff:ffff:ffff:ffff:ffff
22fc3b:1500::/24fc3b:15ff:ffff:ffff:ffff:ffff:ffff:ffff
23fc3b:1600::/24fc3b:16ff:ffff:ffff:ffff:ffff:ffff:ffff
24fc3b:1700::/24fc3b:17ff:ffff:ffff:ffff:ffff:ffff:ffff
25fc3b:1800::/24fc3b:18ff:ffff:ffff:ffff:ffff:ffff:ffff
26fc3b:1900::/24fc3b:19ff:ffff:ffff:ffff:ffff:ffff:ffff
27fc3b:1a00::/24fc3b:1aff:ffff:ffff:ffff:ffff:ffff:ffff
28fc3b:1b00::/24fc3b:1bff:ffff:ffff:ffff:ffff:ffff:ffff
29fc3b:1c00::/24fc3b:1cff:ffff:ffff:ffff:ffff:ffff:ffff
30fc3b:1d00::/24fc3b:1dff:ffff:ffff:ffff:ffff:ffff:ffff
31fc3b:1e00::/24fc3b:1eff:ffff:ffff:ffff:ffff:ffff:ffff
32fc3b:1f00::/24fc3b:1fff:ffff:ffff:ffff:ffff:ffff:ffff
33fc3b:2000::/24fc3b:20ff:ffff:ffff:ffff:ffff:ffff:ffff
34fc3b:2100::/24fc3b:21ff:ffff:ffff:ffff:ffff:ffff:ffff
35fc3b:2200::/24fc3b:22ff:ffff:ffff:ffff:ffff:ffff:ffff
36fc3b:2300::/24fc3b:23ff:ffff:ffff:ffff:ffff:ffff:ffff
37fc3b:2400::/24fc3b:24ff:ffff:ffff:ffff:ffff:ffff:ffff
38fc3b:2500::/24fc3b:25ff:ffff:ffff:ffff:ffff:ffff:ffff
39fc3b:2600::/24fc3b:26ff:ffff:ffff:ffff:ffff:ffff:ffff
40fc3b:2700::/24fc3b:27ff:ffff:ffff:ffff:ffff:ffff:ffff
41fc3b:2800::/24fc3b:28ff:ffff:ffff:ffff:ffff:ffff:ffff
42fc3b:2900::/24fc3b:29ff:ffff:ffff:ffff:ffff:ffff:ffff
43fc3b:2a00::/24fc3b:2aff:ffff:ffff:ffff:ffff:ffff:ffff
44fc3b:2b00::/24fc3b:2bff:ffff:ffff:ffff:ffff:ffff:ffff
45fc3b:2c00::/24fc3b:2cff:ffff:ffff:ffff:ffff:ffff:ffff
46fc3b:2d00::/24fc3b:2dff:ffff:ffff:ffff:ffff:ffff:ffff
47fc3b:2e00::/24fc3b:2eff:ffff:ffff:ffff:ffff:ffff:ffff
48fc3b:2f00::/24fc3b:2fff:ffff:ffff:ffff:ffff:ffff:ffff
49fc3b:3000::/24fc3b:30ff:ffff:ffff:ffff:ffff:ffff:ffff
50fc3b:3100::/24fc3b:31ff:ffff:ffff:ffff:ffff:ffff:ffff
51fc3b:3200::/24fc3b:32ff:ffff:ffff:ffff:ffff:ffff:ffff
52fc3b:3300::/24fc3b:33ff:ffff:ffff:ffff:ffff:ffff:ffff
53fc3b:3400::/24fc3b:34ff:ffff:ffff:ffff:ffff:ffff:ffff
54fc3b:3500::/24fc3b:35ff:ffff:ffff:ffff:ffff:ffff:ffff
55fc3b:3600::/24fc3b:36ff:ffff:ffff:ffff:ffff:ffff:ffff
56fc3b:3700::/24fc3b:37ff:ffff:ffff:ffff:ffff:ffff:ffff
57fc3b:3800::/24fc3b:38ff:ffff:ffff:ffff:ffff:ffff:ffff
58fc3b:3900::/24fc3b:39ff:ffff:ffff:ffff:ffff:ffff:ffff
59fc3b:3a00::/24fc3b:3aff:ffff:ffff:ffff:ffff:ffff:ffff
60fc3b:3b00::/24fc3b:3bff:ffff:ffff:ffff:ffff:ffff:ffff
61fc3b:3c00::/24fc3b:3cff:ffff:ffff:ffff:ffff:ffff:ffff
62fc3b:3d00::/24fc3b:3dff:ffff:ffff:ffff:ffff:ffff:ffff
63fc3b:3e00::/24fc3b:3eff:ffff:ffff:ffff:ffff:ffff:ffff
64fc3b:3f00::/24fc3b:3fff:ffff:ffff:ffff:ffff:ffff:ffff
65fc3b:4000::/24fc3b:40ff:ffff:ffff:ffff:ffff:ffff:ffff
66fc3b:4100::/24fc3b:41ff:ffff:ffff:ffff:ffff:ffff:ffff
67fc3b:4200::/24fc3b:42ff:ffff:ffff:ffff:ffff:ffff:ffff
68fc3b:4300::/24fc3b:43ff:ffff:ffff:ffff:ffff:ffff:ffff
69fc3b:4400::/24fc3b:44ff:ffff:ffff:ffff:ffff:ffff:ffff
70fc3b:4500::/24fc3b:45ff:ffff:ffff:ffff:ffff:ffff:ffff
71fc3b:4600::/24fc3b:46ff:ffff:ffff:ffff:ffff:ffff:ffff
72fc3b:4700::/24fc3b:47ff:ffff:ffff:ffff:ffff:ffff:ffff
73fc3b:4800::/24fc3b:48ff:ffff:ffff:ffff:ffff:ffff:ffff
74fc3b:4900::/24fc3b:49ff:ffff:ffff:ffff:ffff:ffff:ffff
75fc3b:4a00::/24fc3b:4aff:ffff:ffff:ffff:ffff:ffff:ffff
76fc3b:4b00::/24fc3b:4bff:ffff:ffff:ffff:ffff:ffff:ffff
77fc3b:4c00::/24fc3b:4cff:ffff:ffff:ffff:ffff:ffff:ffff
78fc3b:4d00::/24fc3b:4dff:ffff:ffff:ffff:ffff:ffff:ffff
79fc3b:4e00::/24fc3b:4eff:ffff:ffff:ffff:ffff:ffff:ffff
80fc3b:4f00::/24fc3b:4fff:ffff:ffff:ffff:ffff:ffff:ffff
81fc3b:5000::/24fc3b:50ff:ffff:ffff:ffff:ffff:ffff:ffff
82fc3b:5100::/24fc3b:51ff:ffff:ffff:ffff:ffff:ffff:ffff
83fc3b:5200::/24fc3b:52ff:ffff:ffff:ffff:ffff:ffff:ffff
84fc3b:5300::/24fc3b:53ff:ffff:ffff:ffff:ffff:ffff:ffff
85fc3b:5400::/24fc3b:54ff:ffff:ffff:ffff:ffff:ffff:ffff
86fc3b:5500::/24fc3b:55ff:ffff:ffff:ffff:ffff:ffff:ffff
87fc3b:5600::/24fc3b:56ff:ffff:ffff:ffff:ffff:ffff:ffff
88fc3b:5700::/24fc3b:57ff:ffff:ffff:ffff:ffff:ffff:ffff
89fc3b:5800::/24fc3b:58ff:ffff:ffff:ffff:ffff:ffff:ffff
90fc3b:5900::/24fc3b:59ff:ffff:ffff:ffff:ffff:ffff:ffff
91fc3b:5a00::/24fc3b:5aff:ffff:ffff:ffff:ffff:ffff:ffff
92fc3b:5b00::/24fc3b:5bff:ffff:ffff:ffff:ffff:ffff:ffff
93fc3b:5c00::/24fc3b:5cff:ffff:ffff:ffff:ffff:ffff:ffff
94fc3b:5d00::/24fc3b:5dff:ffff:ffff:ffff:ffff:ffff:ffff
95fc3b:5e00::/24fc3b:5eff:ffff:ffff:ffff:ffff:ffff:ffff
96fc3b:5f00::/24fc3b:5fff:ffff:ffff:ffff:ffff:ffff:ffff
97fc3b:6000::/24fc3b:60ff:ffff:ffff:ffff:ffff:ffff:ffff
98fc3b:6100::/24fc3b:61ff:ffff:ffff:ffff:ffff:ffff:ffff
99fc3b:6200::/24fc3b:62ff:ffff:ffff:ffff:ffff:ffff:ffff
100fc3b:6300::/24fc3b:63ff:ffff:ffff:ffff:ffff:ffff:ffff
101fc3b:6400::/24fc3b:64ff:ffff:ffff:ffff:ffff:ffff:ffff
102fc3b:6500::/24fc3b:65ff:ffff:ffff:ffff:ffff:ffff:ffff
103fc3b:6600::/24fc3b:66ff:ffff:ffff:ffff:ffff:ffff:ffff
104fc3b:6700::/24fc3b:67ff:ffff:ffff:ffff:ffff:ffff:ffff
105fc3b:6800::/24fc3b:68ff:ffff:ffff:ffff:ffff:ffff:ffff
106fc3b:6900::/24fc3b:69ff:ffff:ffff:ffff:ffff:ffff:ffff
107fc3b:6a00::/24fc3b:6aff:ffff:ffff:ffff:ffff:ffff:ffff
108fc3b:6b00::/24fc3b:6bff:ffff:ffff:ffff:ffff:ffff:ffff
109fc3b:6c00::/24fc3b:6cff:ffff:ffff:ffff:ffff:ffff:ffff
110fc3b:6d00::/24fc3b:6dff:ffff:ffff:ffff:ffff:ffff:ffff
111fc3b:6e00::/24fc3b:6eff:ffff:ffff:ffff:ffff:ffff:ffff
112fc3b:6f00::/24fc3b:6fff:ffff:ffff:ffff:ffff:ffff:ffff
113fc3b:7000::/24fc3b:70ff:ffff:ffff:ffff:ffff:ffff:ffff
114fc3b:7100::/24fc3b:71ff:ffff:ffff:ffff:ffff:ffff:ffff
115fc3b:7200::/24fc3b:72ff:ffff:ffff:ffff:ffff:ffff:ffff
116fc3b:7300::/24fc3b:73ff:ffff:ffff:ffff:ffff:ffff:ffff
117fc3b:7400::/24fc3b:74ff:ffff:ffff:ffff:ffff:ffff:ffff
118fc3b:7500::/24fc3b:75ff:ffff:ffff:ffff:ffff:ffff:ffff
119fc3b:7600::/24fc3b:76ff:ffff:ffff:ffff:ffff:ffff:ffff
120fc3b:7700::/24fc3b:77ff:ffff:ffff:ffff:ffff:ffff:ffff
121fc3b:7800::/24fc3b:78ff:ffff:ffff:ffff:ffff:ffff:ffff
122fc3b:7900::/24fc3b:79ff:ffff:ffff:ffff:ffff:ffff:ffff
123fc3b:7a00::/24fc3b:7aff:ffff:ffff:ffff:ffff:ffff:ffff
124fc3b:7b00::/24fc3b:7bff:ffff:ffff:ffff:ffff:ffff:ffff
125fc3b:7c00::/24fc3b:7cff:ffff:ffff:ffff:ffff:ffff:ffff
126fc3b:7d00::/24fc3b:7dff:ffff:ffff:ffff:ffff:ffff:ffff
127fc3b:7e00::/24fc3b:7eff:ffff:ffff:ffff:ffff:ffff:ffff
128fc3b:7f00::/24fc3b:7fff:ffff:ffff:ffff:ffff:ffff:ffff
129fc3b:8000::/24fc3b:80ff:ffff:ffff:ffff:ffff:ffff:ffff
130fc3b:8100::/24fc3b:81ff:ffff:ffff:ffff:ffff:ffff:ffff
131fc3b:8200::/24fc3b:82ff:ffff:ffff:ffff:ffff:ffff:ffff
132fc3b:8300::/24fc3b:83ff:ffff:ffff:ffff:ffff:ffff:ffff
133fc3b:8400::/24fc3b:84ff:ffff:ffff:ffff:ffff:ffff:ffff
134fc3b:8500::/24fc3b:85ff:ffff:ffff:ffff:ffff:ffff:ffff
135fc3b:8600::/24fc3b:86ff:ffff:ffff:ffff:ffff:ffff:ffff
136fc3b:8700::/24fc3b:87ff:ffff:ffff:ffff:ffff:ffff:ffff
137fc3b:8800::/24fc3b:88ff:ffff:ffff:ffff:ffff:ffff:ffff
138fc3b:8900::/24fc3b:89ff:ffff:ffff:ffff:ffff:ffff:ffff
139fc3b:8a00::/24fc3b:8aff:ffff:ffff:ffff:ffff:ffff:ffff
140fc3b:8b00::/24fc3b:8bff:ffff:ffff:ffff:ffff:ffff:ffff
141fc3b:8c00::/24fc3b:8cff:ffff:ffff:ffff:ffff:ffff:ffff
142fc3b:8d00::/24fc3b:8dff:ffff:ffff:ffff:ffff:ffff:ffff
143fc3b:8e00::/24fc3b:8eff:ffff:ffff:ffff:ffff:ffff:ffff
144fc3b:8f00::/24fc3b:8fff:ffff:ffff:ffff:ffff:ffff:ffff
145fc3b:9000::/24fc3b:90ff:ffff:ffff:ffff:ffff:ffff:ffff
146fc3b:9100::/24fc3b:91ff:ffff:ffff:ffff:ffff:ffff:ffff
147fc3b:9200::/24fc3b:92ff:ffff:ffff:ffff:ffff:ffff:ffff
148fc3b:9300::/24fc3b:93ff:ffff:ffff:ffff:ffff:ffff:ffff
149fc3b:9400::/24fc3b:94ff:ffff:ffff:ffff:ffff:ffff:ffff
150fc3b:9500::/24fc3b:95ff:ffff:ffff:ffff:ffff:ffff:ffff
151fc3b:9600::/24fc3b:96ff:ffff:ffff:ffff:ffff:ffff:ffff
152fc3b:9700::/24fc3b:97ff:ffff:ffff:ffff:ffff:ffff:ffff
153fc3b:9800::/24fc3b:98ff:ffff:ffff:ffff:ffff:ffff:ffff
154fc3b:9900::/24fc3b:99ff:ffff:ffff:ffff:ffff:ffff:ffff
155fc3b:9a00::/24fc3b:9aff:ffff:ffff:ffff:ffff:ffff:ffff
156fc3b:9b00::/24fc3b:9bff:ffff:ffff:ffff:ffff:ffff:ffff
157fc3b:9c00::/24fc3b:9cff:ffff:ffff:ffff:ffff:ffff:ffff
158fc3b:9d00::/24fc3b:9dff:ffff:ffff:ffff:ffff:ffff:ffff
159fc3b:9e00::/24fc3b:9eff:ffff:ffff:ffff:ffff:ffff:ffff
160fc3b:9f00::/24fc3b:9fff:ffff:ffff:ffff:ffff:ffff:ffff
161fc3b:a000::/24fc3b:a0ff:ffff:ffff:ffff:ffff:ffff:ffff
162fc3b:a100::/24fc3b:a1ff:ffff:ffff:ffff:ffff:ffff:ffff
163fc3b:a200::/24fc3b:a2ff:ffff:ffff:ffff:ffff:ffff:ffff
164fc3b:a300::/24fc3b:a3ff:ffff:ffff:ffff:ffff:ffff:ffff
165fc3b:a400::/24fc3b:a4ff:ffff:ffff:ffff:ffff:ffff:ffff
166fc3b:a500::/24fc3b:a5ff:ffff:ffff:ffff:ffff:ffff:ffff
167fc3b:a600::/24fc3b:a6ff:ffff:ffff:ffff:ffff:ffff:ffff
168fc3b:a700::/24fc3b:a7ff:ffff:ffff:ffff:ffff:ffff:ffff
169fc3b:a800::/24fc3b:a8ff:ffff:ffff:ffff:ffff:ffff:ffff
170fc3b:a900::/24fc3b:a9ff:ffff:ffff:ffff:ffff:ffff:ffff
171fc3b:aa00::/24fc3b:aaff:ffff:ffff:ffff:ffff:ffff:ffff
172fc3b:ab00::/24fc3b:abff:ffff:ffff:ffff:ffff:ffff:ffff
173fc3b:ac00::/24fc3b:acff:ffff:ffff:ffff:ffff:ffff:ffff
174fc3b:ad00::/24fc3b:adff:ffff:ffff:ffff:ffff:ffff:ffff
175fc3b:ae00::/24fc3b:aeff:ffff:ffff:ffff:ffff:ffff:ffff
176fc3b:af00::/24fc3b:afff:ffff:ffff:ffff:ffff:ffff:ffff
177fc3b:b000::/24fc3b:b0ff:ffff:ffff:ffff:ffff:ffff:ffff
178fc3b:b100::/24fc3b:b1ff:ffff:ffff:ffff:ffff:ffff:ffff
179fc3b:b200::/24fc3b:b2ff:ffff:ffff:ffff:ffff:ffff:ffff
180fc3b:b300::/24fc3b:b3ff:ffff:ffff:ffff:ffff:ffff:ffff
181fc3b:b400::/24fc3b:b4ff:ffff:ffff:ffff:ffff:ffff:ffff
182fc3b:b500::/24fc3b:b5ff:ffff:ffff:ffff:ffff:ffff:ffff
183fc3b:b600::/24fc3b:b6ff:ffff:ffff:ffff:ffff:ffff:ffff
184fc3b:b700::/24fc3b:b7ff:ffff:ffff:ffff:ffff:ffff:ffff
185fc3b:b800::/24fc3b:b8ff:ffff:ffff:ffff:ffff:ffff:ffff
186fc3b:b900::/24fc3b:b9ff:ffff:ffff:ffff:ffff:ffff:ffff
187fc3b:ba00::/24fc3b:baff:ffff:ffff:ffff:ffff:ffff:ffff
188fc3b:bb00::/24fc3b:bbff:ffff:ffff:ffff:ffff:ffff:ffff
189fc3b:bc00::/24fc3b:bcff:ffff:ffff:ffff:ffff:ffff:ffff
190fc3b:bd00::/24fc3b:bdff:ffff:ffff:ffff:ffff:ffff:ffff
191fc3b:be00::/24fc3b:beff:ffff:ffff:ffff:ffff:ffff:ffff
192fc3b:bf00::/24fc3b:bfff:ffff:ffff:ffff:ffff:ffff:ffff
193fc3b:c000::/24fc3b:c0ff:ffff:ffff:ffff:ffff:ffff:ffff
194fc3b:c100::/24fc3b:c1ff:ffff:ffff:ffff:ffff:ffff:ffff
195fc3b:c200::/24fc3b:c2ff:ffff:ffff:ffff:ffff:ffff:ffff
196fc3b:c300::/24fc3b:c3ff:ffff:ffff:ffff:ffff:ffff:ffff
197fc3b:c400::/24fc3b:c4ff:ffff:ffff:ffff:ffff:ffff:ffff
198fc3b:c500::/24fc3b:c5ff:ffff:ffff:ffff:ffff:ffff:ffff
199fc3b:c600::/24fc3b:c6ff:ffff:ffff:ffff:ffff:ffff:ffff
200fc3b:c700::/24fc3b:c7ff:ffff:ffff:ffff:ffff:ffff:ffff
201fc3b:c800::/24fc3b:c8ff:ffff:ffff:ffff:ffff:ffff:ffff
202fc3b:c900::/24fc3b:c9ff:ffff:ffff:ffff:ffff:ffff:ffff
203fc3b:ca00::/24fc3b:caff:ffff:ffff:ffff:ffff:ffff:ffff
204fc3b:cb00::/24fc3b:cbff:ffff:ffff:ffff:ffff:ffff:ffff
205fc3b:cc00::/24fc3b:ccff:ffff:ffff:ffff:ffff:ffff:ffff
206fc3b:cd00::/24fc3b:cdff:ffff:ffff:ffff:ffff:ffff:ffff
207fc3b:ce00::/24fc3b:ceff:ffff:ffff:ffff:ffff:ffff:ffff
208fc3b:cf00::/24fc3b:cfff:ffff:ffff:ffff:ffff:ffff:ffff
209fc3b:d000::/24fc3b:d0ff:ffff:ffff:ffff:ffff:ffff:ffff
210fc3b:d100::/24fc3b:d1ff:ffff:ffff:ffff:ffff:ffff:ffff
211fc3b:d200::/24fc3b:d2ff:ffff:ffff:ffff:ffff:ffff:ffff
212fc3b:d300::/24fc3b:d3ff:ffff:ffff:ffff:ffff:ffff:ffff
213fc3b:d400::/24fc3b:d4ff:ffff:ffff:ffff:ffff:ffff:ffff
214fc3b:d500::/24fc3b:d5ff:ffff:ffff:ffff:ffff:ffff:ffff
215fc3b:d600::/24fc3b:d6ff:ffff:ffff:ffff:ffff:ffff:ffff
216fc3b:d700::/24fc3b:d7ff:ffff:ffff:ffff:ffff:ffff:ffff
217fc3b:d800::/24fc3b:d8ff:ffff:ffff:ffff:ffff:ffff:ffff
218fc3b:d900::/24fc3b:d9ff:ffff:ffff:ffff:ffff:ffff:ffff
219fc3b:da00::/24fc3b:daff:ffff:ffff:ffff:ffff:ffff:ffff
220fc3b:db00::/24fc3b:dbff:ffff:ffff:ffff:ffff:ffff:ffff
221fc3b:dc00::/24fc3b:dcff:ffff:ffff:ffff:ffff:ffff:ffff
222fc3b:dd00::/24fc3b:ddff:ffff:ffff:ffff:ffff:ffff:ffff
223fc3b:de00::/24fc3b:deff:ffff:ffff:ffff:ffff:ffff:ffff
224fc3b:df00::/24fc3b:dfff:ffff:ffff:ffff:ffff:ffff:ffff
225fc3b:e000::/24fc3b:e0ff:ffff:ffff:ffff:ffff:ffff:ffff
226fc3b:e100::/24fc3b:e1ff:ffff:ffff:ffff:ffff:ffff:ffff
227fc3b:e200::/24fc3b:e2ff:ffff:ffff:ffff:ffff:ffff:ffff
228fc3b:e300::/24fc3b:e3ff:ffff:ffff:ffff:ffff:ffff:ffff
229fc3b:e400::/24fc3b:e4ff:ffff:ffff:ffff:ffff:ffff:ffff
230fc3b:e500::/24fc3b:e5ff:ffff:ffff:ffff:ffff:ffff:ffff
231fc3b:e600::/24fc3b:e6ff:ffff:ffff:ffff:ffff:ffff:ffff
232fc3b:e700::/24fc3b:e7ff:ffff:ffff:ffff:ffff:ffff:ffff
233fc3b:e800::/24fc3b:e8ff:ffff:ffff:ffff:ffff:ffff:ffff
234fc3b:e900::/24fc3b:e9ff:ffff:ffff:ffff:ffff:ffff:ffff
235fc3b:ea00::/24fc3b:eaff:ffff:ffff:ffff:ffff:ffff:ffff
236fc3b:eb00::/24fc3b:ebff:ffff:ffff:ffff:ffff:ffff:ffff
237fc3b:ec00::/24fc3b:ecff:ffff:ffff:ffff:ffff:ffff:ffff
238fc3b:ed00::/24fc3b:edff:ffff:ffff:ffff:ffff:ffff:ffff
239fc3b:ee00::/24fc3b:eeff:ffff:ffff:ffff:ffff:ffff:ffff
240fc3b:ef00::/24fc3b:efff:ffff:ffff:ffff:ffff:ffff:ffff
241fc3b:f000::/24fc3b:f0ff:ffff:ffff:ffff:ffff:ffff:ffff
242fc3b:f100::/24fc3b:f1ff:ffff:ffff:ffff:ffff:ffff:ffff
243fc3b:f200::/24fc3b:f2ff:ffff:ffff:ffff:ffff:ffff:ffff
244fc3b:f300::/24fc3b:f3ff:ffff:ffff:ffff:ffff:ffff:ffff
245fc3b:f400::/24fc3b:f4ff:ffff:ffff:ffff:ffff:ffff:ffff
246fc3b:f500::/24fc3b:f5ff:ffff:ffff:ffff:ffff:ffff:ffff
247fc3b:f600::/24fc3b:f6ff:ffff:ffff:ffff:ffff:ffff:ffff
248fc3b:f700::/24fc3b:f7ff:ffff:ffff:ffff:ffff:ffff:ffff
249fc3b:f800::/24fc3b:f8ff:ffff:ffff:ffff:ffff:ffff:ffff
250fc3b:f900::/24fc3b:f9ff:ffff:ffff:ffff:ffff:ffff:ffff
251fc3b:fa00::/24fc3b:faff:ffff:ffff:ffff:ffff:ffff:ffff
252fc3b:fb00::/24fc3b:fbff:ffff:ffff:ffff:ffff:ffff:ffff
253fc3b:fc00::/24fc3b:fcff:ffff:ffff:ffff:ffff:ffff:ffff
254fc3b:fd00::/24fc3b:fdff:ffff:ffff:ffff:ffff:ffff:ffff
255fc3b:fe00::/24fc3b:feff:ffff:ffff:ffff:ffff:ffff:ffff
256fc3b:ff00::/24fc3b: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.