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Speed and call quality testTest delay, jitter and speed, with a focus on phone calls.My IP addressYour public IPv4 and IPv6 addresses, provider and address range.WhoIs lookupWho owns a domain or IP address, when it expires, and its DNS.DNS reportEvery DNS record for a domain, with email setup checked.IP subnet calculatorWork out a network's range, mask and hosts, and split it into subnets.

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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
fc4f::/16
First address
fc4f::
Last address
fc4f: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
fc4f:0000:0000:0000:0000:0000:0000:0000
Type
Unique local (ULA) fc00::/7
Private IPv6, like RFC 1918; usually fd00::/8
Reverse DNS zone
f.4.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)

fc4f::/16 makes 256 subnets of /24.

Subnets
#SubnetLast address
1fc4f::/24fc4f:ff:ffff:ffff:ffff:ffff:ffff:ffff
2fc4f:100::/24fc4f:1ff:ffff:ffff:ffff:ffff:ffff:ffff
3fc4f:200::/24fc4f:2ff:ffff:ffff:ffff:ffff:ffff:ffff
4fc4f:300::/24fc4f:3ff:ffff:ffff:ffff:ffff:ffff:ffff
5fc4f:400::/24fc4f:4ff:ffff:ffff:ffff:ffff:ffff:ffff
6fc4f:500::/24fc4f:5ff:ffff:ffff:ffff:ffff:ffff:ffff
7fc4f:600::/24fc4f:6ff:ffff:ffff:ffff:ffff:ffff:ffff
8fc4f:700::/24fc4f:7ff:ffff:ffff:ffff:ffff:ffff:ffff
9fc4f:800::/24fc4f:8ff:ffff:ffff:ffff:ffff:ffff:ffff
10fc4f:900::/24fc4f:9ff:ffff:ffff:ffff:ffff:ffff:ffff
11fc4f:a00::/24fc4f:aff:ffff:ffff:ffff:ffff:ffff:ffff
12fc4f:b00::/24fc4f:bff:ffff:ffff:ffff:ffff:ffff:ffff
13fc4f:c00::/24fc4f:cff:ffff:ffff:ffff:ffff:ffff:ffff
14fc4f:d00::/24fc4f:dff:ffff:ffff:ffff:ffff:ffff:ffff
15fc4f:e00::/24fc4f:eff:ffff:ffff:ffff:ffff:ffff:ffff
16fc4f:f00::/24fc4f:fff:ffff:ffff:ffff:ffff:ffff:ffff
17fc4f:1000::/24fc4f:10ff:ffff:ffff:ffff:ffff:ffff:ffff
18fc4f:1100::/24fc4f:11ff:ffff:ffff:ffff:ffff:ffff:ffff
19fc4f:1200::/24fc4f:12ff:ffff:ffff:ffff:ffff:ffff:ffff
20fc4f:1300::/24fc4f:13ff:ffff:ffff:ffff:ffff:ffff:ffff
21fc4f:1400::/24fc4f:14ff:ffff:ffff:ffff:ffff:ffff:ffff
22fc4f:1500::/24fc4f:15ff:ffff:ffff:ffff:ffff:ffff:ffff
23fc4f:1600::/24fc4f:16ff:ffff:ffff:ffff:ffff:ffff:ffff
24fc4f:1700::/24fc4f:17ff:ffff:ffff:ffff:ffff:ffff:ffff
25fc4f:1800::/24fc4f:18ff:ffff:ffff:ffff:ffff:ffff:ffff
26fc4f:1900::/24fc4f:19ff:ffff:ffff:ffff:ffff:ffff:ffff
27fc4f:1a00::/24fc4f:1aff:ffff:ffff:ffff:ffff:ffff:ffff
28fc4f:1b00::/24fc4f:1bff:ffff:ffff:ffff:ffff:ffff:ffff
29fc4f:1c00::/24fc4f:1cff:ffff:ffff:ffff:ffff:ffff:ffff
30fc4f:1d00::/24fc4f:1dff:ffff:ffff:ffff:ffff:ffff:ffff
31fc4f:1e00::/24fc4f:1eff:ffff:ffff:ffff:ffff:ffff:ffff
32fc4f:1f00::/24fc4f:1fff:ffff:ffff:ffff:ffff:ffff:ffff
33fc4f:2000::/24fc4f:20ff:ffff:ffff:ffff:ffff:ffff:ffff
34fc4f:2100::/24fc4f:21ff:ffff:ffff:ffff:ffff:ffff:ffff
35fc4f:2200::/24fc4f:22ff:ffff:ffff:ffff:ffff:ffff:ffff
36fc4f:2300::/24fc4f:23ff:ffff:ffff:ffff:ffff:ffff:ffff
37fc4f:2400::/24fc4f:24ff:ffff:ffff:ffff:ffff:ffff:ffff
38fc4f:2500::/24fc4f:25ff:ffff:ffff:ffff:ffff:ffff:ffff
39fc4f:2600::/24fc4f:26ff:ffff:ffff:ffff:ffff:ffff:ffff
40fc4f:2700::/24fc4f:27ff:ffff:ffff:ffff:ffff:ffff:ffff
41fc4f:2800::/24fc4f:28ff:ffff:ffff:ffff:ffff:ffff:ffff
42fc4f:2900::/24fc4f:29ff:ffff:ffff:ffff:ffff:ffff:ffff
43fc4f:2a00::/24fc4f:2aff:ffff:ffff:ffff:ffff:ffff:ffff
44fc4f:2b00::/24fc4f:2bff:ffff:ffff:ffff:ffff:ffff:ffff
45fc4f:2c00::/24fc4f:2cff:ffff:ffff:ffff:ffff:ffff:ffff
46fc4f:2d00::/24fc4f:2dff:ffff:ffff:ffff:ffff:ffff:ffff
47fc4f:2e00::/24fc4f:2eff:ffff:ffff:ffff:ffff:ffff:ffff
48fc4f:2f00::/24fc4f:2fff:ffff:ffff:ffff:ffff:ffff:ffff
49fc4f:3000::/24fc4f:30ff:ffff:ffff:ffff:ffff:ffff:ffff
50fc4f:3100::/24fc4f:31ff:ffff:ffff:ffff:ffff:ffff:ffff
51fc4f:3200::/24fc4f:32ff:ffff:ffff:ffff:ffff:ffff:ffff
52fc4f:3300::/24fc4f:33ff:ffff:ffff:ffff:ffff:ffff:ffff
53fc4f:3400::/24fc4f:34ff:ffff:ffff:ffff:ffff:ffff:ffff
54fc4f:3500::/24fc4f:35ff:ffff:ffff:ffff:ffff:ffff:ffff
55fc4f:3600::/24fc4f:36ff:ffff:ffff:ffff:ffff:ffff:ffff
56fc4f:3700::/24fc4f:37ff:ffff:ffff:ffff:ffff:ffff:ffff
57fc4f:3800::/24fc4f:38ff:ffff:ffff:ffff:ffff:ffff:ffff
58fc4f:3900::/24fc4f:39ff:ffff:ffff:ffff:ffff:ffff:ffff
59fc4f:3a00::/24fc4f:3aff:ffff:ffff:ffff:ffff:ffff:ffff
60fc4f:3b00::/24fc4f:3bff:ffff:ffff:ffff:ffff:ffff:ffff
61fc4f:3c00::/24fc4f:3cff:ffff:ffff:ffff:ffff:ffff:ffff
62fc4f:3d00::/24fc4f:3dff:ffff:ffff:ffff:ffff:ffff:ffff
63fc4f:3e00::/24fc4f:3eff:ffff:ffff:ffff:ffff:ffff:ffff
64fc4f:3f00::/24fc4f:3fff:ffff:ffff:ffff:ffff:ffff:ffff
65fc4f:4000::/24fc4f:40ff:ffff:ffff:ffff:ffff:ffff:ffff
66fc4f:4100::/24fc4f:41ff:ffff:ffff:ffff:ffff:ffff:ffff
67fc4f:4200::/24fc4f:42ff:ffff:ffff:ffff:ffff:ffff:ffff
68fc4f:4300::/24fc4f:43ff:ffff:ffff:ffff:ffff:ffff:ffff
69fc4f:4400::/24fc4f:44ff:ffff:ffff:ffff:ffff:ffff:ffff
70fc4f:4500::/24fc4f:45ff:ffff:ffff:ffff:ffff:ffff:ffff
71fc4f:4600::/24fc4f:46ff:ffff:ffff:ffff:ffff:ffff:ffff
72fc4f:4700::/24fc4f:47ff:ffff:ffff:ffff:ffff:ffff:ffff
73fc4f:4800::/24fc4f:48ff:ffff:ffff:ffff:ffff:ffff:ffff
74fc4f:4900::/24fc4f:49ff:ffff:ffff:ffff:ffff:ffff:ffff
75fc4f:4a00::/24fc4f:4aff:ffff:ffff:ffff:ffff:ffff:ffff
76fc4f:4b00::/24fc4f:4bff:ffff:ffff:ffff:ffff:ffff:ffff
77fc4f:4c00::/24fc4f:4cff:ffff:ffff:ffff:ffff:ffff:ffff
78fc4f:4d00::/24fc4f:4dff:ffff:ffff:ffff:ffff:ffff:ffff
79fc4f:4e00::/24fc4f:4eff:ffff:ffff:ffff:ffff:ffff:ffff
80fc4f:4f00::/24fc4f:4fff:ffff:ffff:ffff:ffff:ffff:ffff
81fc4f:5000::/24fc4f:50ff:ffff:ffff:ffff:ffff:ffff:ffff
82fc4f:5100::/24fc4f:51ff:ffff:ffff:ffff:ffff:ffff:ffff
83fc4f:5200::/24fc4f:52ff:ffff:ffff:ffff:ffff:ffff:ffff
84fc4f:5300::/24fc4f:53ff:ffff:ffff:ffff:ffff:ffff:ffff
85fc4f:5400::/24fc4f:54ff:ffff:ffff:ffff:ffff:ffff:ffff
86fc4f:5500::/24fc4f:55ff:ffff:ffff:ffff:ffff:ffff:ffff
87fc4f:5600::/24fc4f:56ff:ffff:ffff:ffff:ffff:ffff:ffff
88fc4f:5700::/24fc4f:57ff:ffff:ffff:ffff:ffff:ffff:ffff
89fc4f:5800::/24fc4f:58ff:ffff:ffff:ffff:ffff:ffff:ffff
90fc4f:5900::/24fc4f:59ff:ffff:ffff:ffff:ffff:ffff:ffff
91fc4f:5a00::/24fc4f:5aff:ffff:ffff:ffff:ffff:ffff:ffff
92fc4f:5b00::/24fc4f:5bff:ffff:ffff:ffff:ffff:ffff:ffff
93fc4f:5c00::/24fc4f:5cff:ffff:ffff:ffff:ffff:ffff:ffff
94fc4f:5d00::/24fc4f:5dff:ffff:ffff:ffff:ffff:ffff:ffff
95fc4f:5e00::/24fc4f:5eff:ffff:ffff:ffff:ffff:ffff:ffff
96fc4f:5f00::/24fc4f:5fff:ffff:ffff:ffff:ffff:ffff:ffff
97fc4f:6000::/24fc4f:60ff:ffff:ffff:ffff:ffff:ffff:ffff
98fc4f:6100::/24fc4f:61ff:ffff:ffff:ffff:ffff:ffff:ffff
99fc4f:6200::/24fc4f:62ff:ffff:ffff:ffff:ffff:ffff:ffff
100fc4f:6300::/24fc4f:63ff:ffff:ffff:ffff:ffff:ffff:ffff
101fc4f:6400::/24fc4f:64ff:ffff:ffff:ffff:ffff:ffff:ffff
102fc4f:6500::/24fc4f:65ff:ffff:ffff:ffff:ffff:ffff:ffff
103fc4f:6600::/24fc4f:66ff:ffff:ffff:ffff:ffff:ffff:ffff
104fc4f:6700::/24fc4f:67ff:ffff:ffff:ffff:ffff:ffff:ffff
105fc4f:6800::/24fc4f:68ff:ffff:ffff:ffff:ffff:ffff:ffff
106fc4f:6900::/24fc4f:69ff:ffff:ffff:ffff:ffff:ffff:ffff
107fc4f:6a00::/24fc4f:6aff:ffff:ffff:ffff:ffff:ffff:ffff
108fc4f:6b00::/24fc4f:6bff:ffff:ffff:ffff:ffff:ffff:ffff
109fc4f:6c00::/24fc4f:6cff:ffff:ffff:ffff:ffff:ffff:ffff
110fc4f:6d00::/24fc4f:6dff:ffff:ffff:ffff:ffff:ffff:ffff
111fc4f:6e00::/24fc4f:6eff:ffff:ffff:ffff:ffff:ffff:ffff
112fc4f:6f00::/24fc4f:6fff:ffff:ffff:ffff:ffff:ffff:ffff
113fc4f:7000::/24fc4f:70ff:ffff:ffff:ffff:ffff:ffff:ffff
114fc4f:7100::/24fc4f:71ff:ffff:ffff:ffff:ffff:ffff:ffff
115fc4f:7200::/24fc4f:72ff:ffff:ffff:ffff:ffff:ffff:ffff
116fc4f:7300::/24fc4f:73ff:ffff:ffff:ffff:ffff:ffff:ffff
117fc4f:7400::/24fc4f:74ff:ffff:ffff:ffff:ffff:ffff:ffff
118fc4f:7500::/24fc4f:75ff:ffff:ffff:ffff:ffff:ffff:ffff
119fc4f:7600::/24fc4f:76ff:ffff:ffff:ffff:ffff:ffff:ffff
120fc4f:7700::/24fc4f:77ff:ffff:ffff:ffff:ffff:ffff:ffff
121fc4f:7800::/24fc4f:78ff:ffff:ffff:ffff:ffff:ffff:ffff
122fc4f:7900::/24fc4f:79ff:ffff:ffff:ffff:ffff:ffff:ffff
123fc4f:7a00::/24fc4f:7aff:ffff:ffff:ffff:ffff:ffff:ffff
124fc4f:7b00::/24fc4f:7bff:ffff:ffff:ffff:ffff:ffff:ffff
125fc4f:7c00::/24fc4f:7cff:ffff:ffff:ffff:ffff:ffff:ffff
126fc4f:7d00::/24fc4f:7dff:ffff:ffff:ffff:ffff:ffff:ffff
127fc4f:7e00::/24fc4f:7eff:ffff:ffff:ffff:ffff:ffff:ffff
128fc4f:7f00::/24fc4f:7fff:ffff:ffff:ffff:ffff:ffff:ffff
129fc4f:8000::/24fc4f:80ff:ffff:ffff:ffff:ffff:ffff:ffff
130fc4f:8100::/24fc4f:81ff:ffff:ffff:ffff:ffff:ffff:ffff
131fc4f:8200::/24fc4f:82ff:ffff:ffff:ffff:ffff:ffff:ffff
132fc4f:8300::/24fc4f:83ff:ffff:ffff:ffff:ffff:ffff:ffff
133fc4f:8400::/24fc4f:84ff:ffff:ffff:ffff:ffff:ffff:ffff
134fc4f:8500::/24fc4f:85ff:ffff:ffff:ffff:ffff:ffff:ffff
135fc4f:8600::/24fc4f:86ff:ffff:ffff:ffff:ffff:ffff:ffff
136fc4f:8700::/24fc4f:87ff:ffff:ffff:ffff:ffff:ffff:ffff
137fc4f:8800::/24fc4f:88ff:ffff:ffff:ffff:ffff:ffff:ffff
138fc4f:8900::/24fc4f:89ff:ffff:ffff:ffff:ffff:ffff:ffff
139fc4f:8a00::/24fc4f:8aff:ffff:ffff:ffff:ffff:ffff:ffff
140fc4f:8b00::/24fc4f:8bff:ffff:ffff:ffff:ffff:ffff:ffff
141fc4f:8c00::/24fc4f:8cff:ffff:ffff:ffff:ffff:ffff:ffff
142fc4f:8d00::/24fc4f:8dff:ffff:ffff:ffff:ffff:ffff:ffff
143fc4f:8e00::/24fc4f:8eff:ffff:ffff:ffff:ffff:ffff:ffff
144fc4f:8f00::/24fc4f:8fff:ffff:ffff:ffff:ffff:ffff:ffff
145fc4f:9000::/24fc4f:90ff:ffff:ffff:ffff:ffff:ffff:ffff
146fc4f:9100::/24fc4f:91ff:ffff:ffff:ffff:ffff:ffff:ffff
147fc4f:9200::/24fc4f:92ff:ffff:ffff:ffff:ffff:ffff:ffff
148fc4f:9300::/24fc4f:93ff:ffff:ffff:ffff:ffff:ffff:ffff
149fc4f:9400::/24fc4f:94ff:ffff:ffff:ffff:ffff:ffff:ffff
150fc4f:9500::/24fc4f:95ff:ffff:ffff:ffff:ffff:ffff:ffff
151fc4f:9600::/24fc4f:96ff:ffff:ffff:ffff:ffff:ffff:ffff
152fc4f:9700::/24fc4f:97ff:ffff:ffff:ffff:ffff:ffff:ffff
153fc4f:9800::/24fc4f:98ff:ffff:ffff:ffff:ffff:ffff:ffff
154fc4f:9900::/24fc4f:99ff:ffff:ffff:ffff:ffff:ffff:ffff
155fc4f:9a00::/24fc4f:9aff:ffff:ffff:ffff:ffff:ffff:ffff
156fc4f:9b00::/24fc4f:9bff:ffff:ffff:ffff:ffff:ffff:ffff
157fc4f:9c00::/24fc4f:9cff:ffff:ffff:ffff:ffff:ffff:ffff
158fc4f:9d00::/24fc4f:9dff:ffff:ffff:ffff:ffff:ffff:ffff
159fc4f:9e00::/24fc4f:9eff:ffff:ffff:ffff:ffff:ffff:ffff
160fc4f:9f00::/24fc4f:9fff:ffff:ffff:ffff:ffff:ffff:ffff
161fc4f:a000::/24fc4f:a0ff:ffff:ffff:ffff:ffff:ffff:ffff
162fc4f:a100::/24fc4f:a1ff:ffff:ffff:ffff:ffff:ffff:ffff
163fc4f:a200::/24fc4f:a2ff:ffff:ffff:ffff:ffff:ffff:ffff
164fc4f:a300::/24fc4f:a3ff:ffff:ffff:ffff:ffff:ffff:ffff
165fc4f:a400::/24fc4f:a4ff:ffff:ffff:ffff:ffff:ffff:ffff
166fc4f:a500::/24fc4f:a5ff:ffff:ffff:ffff:ffff:ffff:ffff
167fc4f:a600::/24fc4f:a6ff:ffff:ffff:ffff:ffff:ffff:ffff
168fc4f:a700::/24fc4f:a7ff:ffff:ffff:ffff:ffff:ffff:ffff
169fc4f:a800::/24fc4f:a8ff:ffff:ffff:ffff:ffff:ffff:ffff
170fc4f:a900::/24fc4f:a9ff:ffff:ffff:ffff:ffff:ffff:ffff
171fc4f:aa00::/24fc4f:aaff:ffff:ffff:ffff:ffff:ffff:ffff
172fc4f:ab00::/24fc4f:abff:ffff:ffff:ffff:ffff:ffff:ffff
173fc4f:ac00::/24fc4f:acff:ffff:ffff:ffff:ffff:ffff:ffff
174fc4f:ad00::/24fc4f:adff:ffff:ffff:ffff:ffff:ffff:ffff
175fc4f:ae00::/24fc4f:aeff:ffff:ffff:ffff:ffff:ffff:ffff
176fc4f:af00::/24fc4f:afff:ffff:ffff:ffff:ffff:ffff:ffff
177fc4f:b000::/24fc4f:b0ff:ffff:ffff:ffff:ffff:ffff:ffff
178fc4f:b100::/24fc4f:b1ff:ffff:ffff:ffff:ffff:ffff:ffff
179fc4f:b200::/24fc4f:b2ff:ffff:ffff:ffff:ffff:ffff:ffff
180fc4f:b300::/24fc4f:b3ff:ffff:ffff:ffff:ffff:ffff:ffff
181fc4f:b400::/24fc4f:b4ff:ffff:ffff:ffff:ffff:ffff:ffff
182fc4f:b500::/24fc4f:b5ff:ffff:ffff:ffff:ffff:ffff:ffff
183fc4f:b600::/24fc4f:b6ff:ffff:ffff:ffff:ffff:ffff:ffff
184fc4f:b700::/24fc4f:b7ff:ffff:ffff:ffff:ffff:ffff:ffff
185fc4f:b800::/24fc4f:b8ff:ffff:ffff:ffff:ffff:ffff:ffff
186fc4f:b900::/24fc4f:b9ff:ffff:ffff:ffff:ffff:ffff:ffff
187fc4f:ba00::/24fc4f:baff:ffff:ffff:ffff:ffff:ffff:ffff
188fc4f:bb00::/24fc4f:bbff:ffff:ffff:ffff:ffff:ffff:ffff
189fc4f:bc00::/24fc4f:bcff:ffff:ffff:ffff:ffff:ffff:ffff
190fc4f:bd00::/24fc4f:bdff:ffff:ffff:ffff:ffff:ffff:ffff
191fc4f:be00::/24fc4f:beff:ffff:ffff:ffff:ffff:ffff:ffff
192fc4f:bf00::/24fc4f:bfff:ffff:ffff:ffff:ffff:ffff:ffff
193fc4f:c000::/24fc4f:c0ff:ffff:ffff:ffff:ffff:ffff:ffff
194fc4f:c100::/24fc4f:c1ff:ffff:ffff:ffff:ffff:ffff:ffff
195fc4f:c200::/24fc4f:c2ff:ffff:ffff:ffff:ffff:ffff:ffff
196fc4f:c300::/24fc4f:c3ff:ffff:ffff:ffff:ffff:ffff:ffff
197fc4f:c400::/24fc4f:c4ff:ffff:ffff:ffff:ffff:ffff:ffff
198fc4f:c500::/24fc4f:c5ff:ffff:ffff:ffff:ffff:ffff:ffff
199fc4f:c600::/24fc4f:c6ff:ffff:ffff:ffff:ffff:ffff:ffff
200fc4f:c700::/24fc4f:c7ff:ffff:ffff:ffff:ffff:ffff:ffff
201fc4f:c800::/24fc4f:c8ff:ffff:ffff:ffff:ffff:ffff:ffff
202fc4f:c900::/24fc4f:c9ff:ffff:ffff:ffff:ffff:ffff:ffff
203fc4f:ca00::/24fc4f:caff:ffff:ffff:ffff:ffff:ffff:ffff
204fc4f:cb00::/24fc4f:cbff:ffff:ffff:ffff:ffff:ffff:ffff
205fc4f:cc00::/24fc4f:ccff:ffff:ffff:ffff:ffff:ffff:ffff
206fc4f:cd00::/24fc4f:cdff:ffff:ffff:ffff:ffff:ffff:ffff
207fc4f:ce00::/24fc4f:ceff:ffff:ffff:ffff:ffff:ffff:ffff
208fc4f:cf00::/24fc4f:cfff:ffff:ffff:ffff:ffff:ffff:ffff
209fc4f:d000::/24fc4f:d0ff:ffff:ffff:ffff:ffff:ffff:ffff
210fc4f:d100::/24fc4f:d1ff:ffff:ffff:ffff:ffff:ffff:ffff
211fc4f:d200::/24fc4f:d2ff:ffff:ffff:ffff:ffff:ffff:ffff
212fc4f:d300::/24fc4f:d3ff:ffff:ffff:ffff:ffff:ffff:ffff
213fc4f:d400::/24fc4f:d4ff:ffff:ffff:ffff:ffff:ffff:ffff
214fc4f:d500::/24fc4f:d5ff:ffff:ffff:ffff:ffff:ffff:ffff
215fc4f:d600::/24fc4f:d6ff:ffff:ffff:ffff:ffff:ffff:ffff
216fc4f:d700::/24fc4f:d7ff:ffff:ffff:ffff:ffff:ffff:ffff
217fc4f:d800::/24fc4f:d8ff:ffff:ffff:ffff:ffff:ffff:ffff
218fc4f:d900::/24fc4f:d9ff:ffff:ffff:ffff:ffff:ffff:ffff
219fc4f:da00::/24fc4f:daff:ffff:ffff:ffff:ffff:ffff:ffff
220fc4f:db00::/24fc4f:dbff:ffff:ffff:ffff:ffff:ffff:ffff
221fc4f:dc00::/24fc4f:dcff:ffff:ffff:ffff:ffff:ffff:ffff
222fc4f:dd00::/24fc4f:ddff:ffff:ffff:ffff:ffff:ffff:ffff
223fc4f:de00::/24fc4f:deff:ffff:ffff:ffff:ffff:ffff:ffff
224fc4f:df00::/24fc4f:dfff:ffff:ffff:ffff:ffff:ffff:ffff
225fc4f:e000::/24fc4f:e0ff:ffff:ffff:ffff:ffff:ffff:ffff
226fc4f:e100::/24fc4f:e1ff:ffff:ffff:ffff:ffff:ffff:ffff
227fc4f:e200::/24fc4f:e2ff:ffff:ffff:ffff:ffff:ffff:ffff
228fc4f:e300::/24fc4f:e3ff:ffff:ffff:ffff:ffff:ffff:ffff
229fc4f:e400::/24fc4f:e4ff:ffff:ffff:ffff:ffff:ffff:ffff
230fc4f:e500::/24fc4f:e5ff:ffff:ffff:ffff:ffff:ffff:ffff
231fc4f:e600::/24fc4f:e6ff:ffff:ffff:ffff:ffff:ffff:ffff
232fc4f:e700::/24fc4f:e7ff:ffff:ffff:ffff:ffff:ffff:ffff
233fc4f:e800::/24fc4f:e8ff:ffff:ffff:ffff:ffff:ffff:ffff
234fc4f:e900::/24fc4f:e9ff:ffff:ffff:ffff:ffff:ffff:ffff
235fc4f:ea00::/24fc4f:eaff:ffff:ffff:ffff:ffff:ffff:ffff
236fc4f:eb00::/24fc4f:ebff:ffff:ffff:ffff:ffff:ffff:ffff
237fc4f:ec00::/24fc4f:ecff:ffff:ffff:ffff:ffff:ffff:ffff
238fc4f:ed00::/24fc4f:edff:ffff:ffff:ffff:ffff:ffff:ffff
239fc4f:ee00::/24fc4f:eeff:ffff:ffff:ffff:ffff:ffff:ffff
240fc4f:ef00::/24fc4f:efff:ffff:ffff:ffff:ffff:ffff:ffff
241fc4f:f000::/24fc4f:f0ff:ffff:ffff:ffff:ffff:ffff:ffff
242fc4f:f100::/24fc4f:f1ff:ffff:ffff:ffff:ffff:ffff:ffff
243fc4f:f200::/24fc4f:f2ff:ffff:ffff:ffff:ffff:ffff:ffff
244fc4f:f300::/24fc4f:f3ff:ffff:ffff:ffff:ffff:ffff:ffff
245fc4f:f400::/24fc4f:f4ff:ffff:ffff:ffff:ffff:ffff:ffff
246fc4f:f500::/24fc4f:f5ff:ffff:ffff:ffff:ffff:ffff:ffff
247fc4f:f600::/24fc4f:f6ff:ffff:ffff:ffff:ffff:ffff:ffff
248fc4f:f700::/24fc4f:f7ff:ffff:ffff:ffff:ffff:ffff:ffff
249fc4f:f800::/24fc4f:f8ff:ffff:ffff:ffff:ffff:ffff:ffff
250fc4f:f900::/24fc4f:f9ff:ffff:ffff:ffff:ffff:ffff:ffff
251fc4f:fa00::/24fc4f:faff:ffff:ffff:ffff:ffff:ffff:ffff
252fc4f:fb00::/24fc4f:fbff:ffff:ffff:ffff:ffff:ffff:ffff
253fc4f:fc00::/24fc4f:fcff:ffff:ffff:ffff:ffff:ffff:ffff
254fc4f:fd00::/24fc4f:fdff:ffff:ffff:ffff:ffff:ffff:ffff
255fc4f:fe00::/24fc4f:feff:ffff:ffff:ffff:ffff:ffff:ffff
256fc4f:ff00::/24fc4f: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.