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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
fc8d::/16
First address
fc8d::
Last address
fc8d: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
fc8d:0000:0000:0000:0000:0000:0000:0000
Type
Unique local (ULA) fc00::/7
Private IPv6, like RFC 1918; usually fd00::/8
Reverse DNS zone
d.8.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)

fc8d::/16 makes 256 subnets of /24.

Subnets
#SubnetLast address
1fc8d::/24fc8d:ff:ffff:ffff:ffff:ffff:ffff:ffff
2fc8d:100::/24fc8d:1ff:ffff:ffff:ffff:ffff:ffff:ffff
3fc8d:200::/24fc8d:2ff:ffff:ffff:ffff:ffff:ffff:ffff
4fc8d:300::/24fc8d:3ff:ffff:ffff:ffff:ffff:ffff:ffff
5fc8d:400::/24fc8d:4ff:ffff:ffff:ffff:ffff:ffff:ffff
6fc8d:500::/24fc8d:5ff:ffff:ffff:ffff:ffff:ffff:ffff
7fc8d:600::/24fc8d:6ff:ffff:ffff:ffff:ffff:ffff:ffff
8fc8d:700::/24fc8d:7ff:ffff:ffff:ffff:ffff:ffff:ffff
9fc8d:800::/24fc8d:8ff:ffff:ffff:ffff:ffff:ffff:ffff
10fc8d:900::/24fc8d:9ff:ffff:ffff:ffff:ffff:ffff:ffff
11fc8d:a00::/24fc8d:aff:ffff:ffff:ffff:ffff:ffff:ffff
12fc8d:b00::/24fc8d:bff:ffff:ffff:ffff:ffff:ffff:ffff
13fc8d:c00::/24fc8d:cff:ffff:ffff:ffff:ffff:ffff:ffff
14fc8d:d00::/24fc8d:dff:ffff:ffff:ffff:ffff:ffff:ffff
15fc8d:e00::/24fc8d:eff:ffff:ffff:ffff:ffff:ffff:ffff
16fc8d:f00::/24fc8d:fff:ffff:ffff:ffff:ffff:ffff:ffff
17fc8d:1000::/24fc8d:10ff:ffff:ffff:ffff:ffff:ffff:ffff
18fc8d:1100::/24fc8d:11ff:ffff:ffff:ffff:ffff:ffff:ffff
19fc8d:1200::/24fc8d:12ff:ffff:ffff:ffff:ffff:ffff:ffff
20fc8d:1300::/24fc8d:13ff:ffff:ffff:ffff:ffff:ffff:ffff
21fc8d:1400::/24fc8d:14ff:ffff:ffff:ffff:ffff:ffff:ffff
22fc8d:1500::/24fc8d:15ff:ffff:ffff:ffff:ffff:ffff:ffff
23fc8d:1600::/24fc8d:16ff:ffff:ffff:ffff:ffff:ffff:ffff
24fc8d:1700::/24fc8d:17ff:ffff:ffff:ffff:ffff:ffff:ffff
25fc8d:1800::/24fc8d:18ff:ffff:ffff:ffff:ffff:ffff:ffff
26fc8d:1900::/24fc8d:19ff:ffff:ffff:ffff:ffff:ffff:ffff
27fc8d:1a00::/24fc8d:1aff:ffff:ffff:ffff:ffff:ffff:ffff
28fc8d:1b00::/24fc8d:1bff:ffff:ffff:ffff:ffff:ffff:ffff
29fc8d:1c00::/24fc8d:1cff:ffff:ffff:ffff:ffff:ffff:ffff
30fc8d:1d00::/24fc8d:1dff:ffff:ffff:ffff:ffff:ffff:ffff
31fc8d:1e00::/24fc8d:1eff:ffff:ffff:ffff:ffff:ffff:ffff
32fc8d:1f00::/24fc8d:1fff:ffff:ffff:ffff:ffff:ffff:ffff
33fc8d:2000::/24fc8d:20ff:ffff:ffff:ffff:ffff:ffff:ffff
34fc8d:2100::/24fc8d:21ff:ffff:ffff:ffff:ffff:ffff:ffff
35fc8d:2200::/24fc8d:22ff:ffff:ffff:ffff:ffff:ffff:ffff
36fc8d:2300::/24fc8d:23ff:ffff:ffff:ffff:ffff:ffff:ffff
37fc8d:2400::/24fc8d:24ff:ffff:ffff:ffff:ffff:ffff:ffff
38fc8d:2500::/24fc8d:25ff:ffff:ffff:ffff:ffff:ffff:ffff
39fc8d:2600::/24fc8d:26ff:ffff:ffff:ffff:ffff:ffff:ffff
40fc8d:2700::/24fc8d:27ff:ffff:ffff:ffff:ffff:ffff:ffff
41fc8d:2800::/24fc8d:28ff:ffff:ffff:ffff:ffff:ffff:ffff
42fc8d:2900::/24fc8d:29ff:ffff:ffff:ffff:ffff:ffff:ffff
43fc8d:2a00::/24fc8d:2aff:ffff:ffff:ffff:ffff:ffff:ffff
44fc8d:2b00::/24fc8d:2bff:ffff:ffff:ffff:ffff:ffff:ffff
45fc8d:2c00::/24fc8d:2cff:ffff:ffff:ffff:ffff:ffff:ffff
46fc8d:2d00::/24fc8d:2dff:ffff:ffff:ffff:ffff:ffff:ffff
47fc8d:2e00::/24fc8d:2eff:ffff:ffff:ffff:ffff:ffff:ffff
48fc8d:2f00::/24fc8d:2fff:ffff:ffff:ffff:ffff:ffff:ffff
49fc8d:3000::/24fc8d:30ff:ffff:ffff:ffff:ffff:ffff:ffff
50fc8d:3100::/24fc8d:31ff:ffff:ffff:ffff:ffff:ffff:ffff
51fc8d:3200::/24fc8d:32ff:ffff:ffff:ffff:ffff:ffff:ffff
52fc8d:3300::/24fc8d:33ff:ffff:ffff:ffff:ffff:ffff:ffff
53fc8d:3400::/24fc8d:34ff:ffff:ffff:ffff:ffff:ffff:ffff
54fc8d:3500::/24fc8d:35ff:ffff:ffff:ffff:ffff:ffff:ffff
55fc8d:3600::/24fc8d:36ff:ffff:ffff:ffff:ffff:ffff:ffff
56fc8d:3700::/24fc8d:37ff:ffff:ffff:ffff:ffff:ffff:ffff
57fc8d:3800::/24fc8d:38ff:ffff:ffff:ffff:ffff:ffff:ffff
58fc8d:3900::/24fc8d:39ff:ffff:ffff:ffff:ffff:ffff:ffff
59fc8d:3a00::/24fc8d:3aff:ffff:ffff:ffff:ffff:ffff:ffff
60fc8d:3b00::/24fc8d:3bff:ffff:ffff:ffff:ffff:ffff:ffff
61fc8d:3c00::/24fc8d:3cff:ffff:ffff:ffff:ffff:ffff:ffff
62fc8d:3d00::/24fc8d:3dff:ffff:ffff:ffff:ffff:ffff:ffff
63fc8d:3e00::/24fc8d:3eff:ffff:ffff:ffff:ffff:ffff:ffff
64fc8d:3f00::/24fc8d:3fff:ffff:ffff:ffff:ffff:ffff:ffff
65fc8d:4000::/24fc8d:40ff:ffff:ffff:ffff:ffff:ffff:ffff
66fc8d:4100::/24fc8d:41ff:ffff:ffff:ffff:ffff:ffff:ffff
67fc8d:4200::/24fc8d:42ff:ffff:ffff:ffff:ffff:ffff:ffff
68fc8d:4300::/24fc8d:43ff:ffff:ffff:ffff:ffff:ffff:ffff
69fc8d:4400::/24fc8d:44ff:ffff:ffff:ffff:ffff:ffff:ffff
70fc8d:4500::/24fc8d:45ff:ffff:ffff:ffff:ffff:ffff:ffff
71fc8d:4600::/24fc8d:46ff:ffff:ffff:ffff:ffff:ffff:ffff
72fc8d:4700::/24fc8d:47ff:ffff:ffff:ffff:ffff:ffff:ffff
73fc8d:4800::/24fc8d:48ff:ffff:ffff:ffff:ffff:ffff:ffff
74fc8d:4900::/24fc8d:49ff:ffff:ffff:ffff:ffff:ffff:ffff
75fc8d:4a00::/24fc8d:4aff:ffff:ffff:ffff:ffff:ffff:ffff
76fc8d:4b00::/24fc8d:4bff:ffff:ffff:ffff:ffff:ffff:ffff
77fc8d:4c00::/24fc8d:4cff:ffff:ffff:ffff:ffff:ffff:ffff
78fc8d:4d00::/24fc8d:4dff:ffff:ffff:ffff:ffff:ffff:ffff
79fc8d:4e00::/24fc8d:4eff:ffff:ffff:ffff:ffff:ffff:ffff
80fc8d:4f00::/24fc8d:4fff:ffff:ffff:ffff:ffff:ffff:ffff
81fc8d:5000::/24fc8d:50ff:ffff:ffff:ffff:ffff:ffff:ffff
82fc8d:5100::/24fc8d:51ff:ffff:ffff:ffff:ffff:ffff:ffff
83fc8d:5200::/24fc8d:52ff:ffff:ffff:ffff:ffff:ffff:ffff
84fc8d:5300::/24fc8d:53ff:ffff:ffff:ffff:ffff:ffff:ffff
85fc8d:5400::/24fc8d:54ff:ffff:ffff:ffff:ffff:ffff:ffff
86fc8d:5500::/24fc8d:55ff:ffff:ffff:ffff:ffff:ffff:ffff
87fc8d:5600::/24fc8d:56ff:ffff:ffff:ffff:ffff:ffff:ffff
88fc8d:5700::/24fc8d:57ff:ffff:ffff:ffff:ffff:ffff:ffff
89fc8d:5800::/24fc8d:58ff:ffff:ffff:ffff:ffff:ffff:ffff
90fc8d:5900::/24fc8d:59ff:ffff:ffff:ffff:ffff:ffff:ffff
91fc8d:5a00::/24fc8d:5aff:ffff:ffff:ffff:ffff:ffff:ffff
92fc8d:5b00::/24fc8d:5bff:ffff:ffff:ffff:ffff:ffff:ffff
93fc8d:5c00::/24fc8d:5cff:ffff:ffff:ffff:ffff:ffff:ffff
94fc8d:5d00::/24fc8d:5dff:ffff:ffff:ffff:ffff:ffff:ffff
95fc8d:5e00::/24fc8d:5eff:ffff:ffff:ffff:ffff:ffff:ffff
96fc8d:5f00::/24fc8d:5fff:ffff:ffff:ffff:ffff:ffff:ffff
97fc8d:6000::/24fc8d:60ff:ffff:ffff:ffff:ffff:ffff:ffff
98fc8d:6100::/24fc8d:61ff:ffff:ffff:ffff:ffff:ffff:ffff
99fc8d:6200::/24fc8d:62ff:ffff:ffff:ffff:ffff:ffff:ffff
100fc8d:6300::/24fc8d:63ff:ffff:ffff:ffff:ffff:ffff:ffff
101fc8d:6400::/24fc8d:64ff:ffff:ffff:ffff:ffff:ffff:ffff
102fc8d:6500::/24fc8d:65ff:ffff:ffff:ffff:ffff:ffff:ffff
103fc8d:6600::/24fc8d:66ff:ffff:ffff:ffff:ffff:ffff:ffff
104fc8d:6700::/24fc8d:67ff:ffff:ffff:ffff:ffff:ffff:ffff
105fc8d:6800::/24fc8d:68ff:ffff:ffff:ffff:ffff:ffff:ffff
106fc8d:6900::/24fc8d:69ff:ffff:ffff:ffff:ffff:ffff:ffff
107fc8d:6a00::/24fc8d:6aff:ffff:ffff:ffff:ffff:ffff:ffff
108fc8d:6b00::/24fc8d:6bff:ffff:ffff:ffff:ffff:ffff:ffff
109fc8d:6c00::/24fc8d:6cff:ffff:ffff:ffff:ffff:ffff:ffff
110fc8d:6d00::/24fc8d:6dff:ffff:ffff:ffff:ffff:ffff:ffff
111fc8d:6e00::/24fc8d:6eff:ffff:ffff:ffff:ffff:ffff:ffff
112fc8d:6f00::/24fc8d:6fff:ffff:ffff:ffff:ffff:ffff:ffff
113fc8d:7000::/24fc8d:70ff:ffff:ffff:ffff:ffff:ffff:ffff
114fc8d:7100::/24fc8d:71ff:ffff:ffff:ffff:ffff:ffff:ffff
115fc8d:7200::/24fc8d:72ff:ffff:ffff:ffff:ffff:ffff:ffff
116fc8d:7300::/24fc8d:73ff:ffff:ffff:ffff:ffff:ffff:ffff
117fc8d:7400::/24fc8d:74ff:ffff:ffff:ffff:ffff:ffff:ffff
118fc8d:7500::/24fc8d:75ff:ffff:ffff:ffff:ffff:ffff:ffff
119fc8d:7600::/24fc8d:76ff:ffff:ffff:ffff:ffff:ffff:ffff
120fc8d:7700::/24fc8d:77ff:ffff:ffff:ffff:ffff:ffff:ffff
121fc8d:7800::/24fc8d:78ff:ffff:ffff:ffff:ffff:ffff:ffff
122fc8d:7900::/24fc8d:79ff:ffff:ffff:ffff:ffff:ffff:ffff
123fc8d:7a00::/24fc8d:7aff:ffff:ffff:ffff:ffff:ffff:ffff
124fc8d:7b00::/24fc8d:7bff:ffff:ffff:ffff:ffff:ffff:ffff
125fc8d:7c00::/24fc8d:7cff:ffff:ffff:ffff:ffff:ffff:ffff
126fc8d:7d00::/24fc8d:7dff:ffff:ffff:ffff:ffff:ffff:ffff
127fc8d:7e00::/24fc8d:7eff:ffff:ffff:ffff:ffff:ffff:ffff
128fc8d:7f00::/24fc8d:7fff:ffff:ffff:ffff:ffff:ffff:ffff
129fc8d:8000::/24fc8d:80ff:ffff:ffff:ffff:ffff:ffff:ffff
130fc8d:8100::/24fc8d:81ff:ffff:ffff:ffff:ffff:ffff:ffff
131fc8d:8200::/24fc8d:82ff:ffff:ffff:ffff:ffff:ffff:ffff
132fc8d:8300::/24fc8d:83ff:ffff:ffff:ffff:ffff:ffff:ffff
133fc8d:8400::/24fc8d:84ff:ffff:ffff:ffff:ffff:ffff:ffff
134fc8d:8500::/24fc8d:85ff:ffff:ffff:ffff:ffff:ffff:ffff
135fc8d:8600::/24fc8d:86ff:ffff:ffff:ffff:ffff:ffff:ffff
136fc8d:8700::/24fc8d:87ff:ffff:ffff:ffff:ffff:ffff:ffff
137fc8d:8800::/24fc8d:88ff:ffff:ffff:ffff:ffff:ffff:ffff
138fc8d:8900::/24fc8d:89ff:ffff:ffff:ffff:ffff:ffff:ffff
139fc8d:8a00::/24fc8d:8aff:ffff:ffff:ffff:ffff:ffff:ffff
140fc8d:8b00::/24fc8d:8bff:ffff:ffff:ffff:ffff:ffff:ffff
141fc8d:8c00::/24fc8d:8cff:ffff:ffff:ffff:ffff:ffff:ffff
142fc8d:8d00::/24fc8d:8dff:ffff:ffff:ffff:ffff:ffff:ffff
143fc8d:8e00::/24fc8d:8eff:ffff:ffff:ffff:ffff:ffff:ffff
144fc8d:8f00::/24fc8d:8fff:ffff:ffff:ffff:ffff:ffff:ffff
145fc8d:9000::/24fc8d:90ff:ffff:ffff:ffff:ffff:ffff:ffff
146fc8d:9100::/24fc8d:91ff:ffff:ffff:ffff:ffff:ffff:ffff
147fc8d:9200::/24fc8d:92ff:ffff:ffff:ffff:ffff:ffff:ffff
148fc8d:9300::/24fc8d:93ff:ffff:ffff:ffff:ffff:ffff:ffff
149fc8d:9400::/24fc8d:94ff:ffff:ffff:ffff:ffff:ffff:ffff
150fc8d:9500::/24fc8d:95ff:ffff:ffff:ffff:ffff:ffff:ffff
151fc8d:9600::/24fc8d:96ff:ffff:ffff:ffff:ffff:ffff:ffff
152fc8d:9700::/24fc8d:97ff:ffff:ffff:ffff:ffff:ffff:ffff
153fc8d:9800::/24fc8d:98ff:ffff:ffff:ffff:ffff:ffff:ffff
154fc8d:9900::/24fc8d:99ff:ffff:ffff:ffff:ffff:ffff:ffff
155fc8d:9a00::/24fc8d:9aff:ffff:ffff:ffff:ffff:ffff:ffff
156fc8d:9b00::/24fc8d:9bff:ffff:ffff:ffff:ffff:ffff:ffff
157fc8d:9c00::/24fc8d:9cff:ffff:ffff:ffff:ffff:ffff:ffff
158fc8d:9d00::/24fc8d:9dff:ffff:ffff:ffff:ffff:ffff:ffff
159fc8d:9e00::/24fc8d:9eff:ffff:ffff:ffff:ffff:ffff:ffff
160fc8d:9f00::/24fc8d:9fff:ffff:ffff:ffff:ffff:ffff:ffff
161fc8d:a000::/24fc8d:a0ff:ffff:ffff:ffff:ffff:ffff:ffff
162fc8d:a100::/24fc8d:a1ff:ffff:ffff:ffff:ffff:ffff:ffff
163fc8d:a200::/24fc8d:a2ff:ffff:ffff:ffff:ffff:ffff:ffff
164fc8d:a300::/24fc8d:a3ff:ffff:ffff:ffff:ffff:ffff:ffff
165fc8d:a400::/24fc8d:a4ff:ffff:ffff:ffff:ffff:ffff:ffff
166fc8d:a500::/24fc8d:a5ff:ffff:ffff:ffff:ffff:ffff:ffff
167fc8d:a600::/24fc8d:a6ff:ffff:ffff:ffff:ffff:ffff:ffff
168fc8d:a700::/24fc8d:a7ff:ffff:ffff:ffff:ffff:ffff:ffff
169fc8d:a800::/24fc8d:a8ff:ffff:ffff:ffff:ffff:ffff:ffff
170fc8d:a900::/24fc8d:a9ff:ffff:ffff:ffff:ffff:ffff:ffff
171fc8d:aa00::/24fc8d:aaff:ffff:ffff:ffff:ffff:ffff:ffff
172fc8d:ab00::/24fc8d:abff:ffff:ffff:ffff:ffff:ffff:ffff
173fc8d:ac00::/24fc8d:acff:ffff:ffff:ffff:ffff:ffff:ffff
174fc8d:ad00::/24fc8d:adff:ffff:ffff:ffff:ffff:ffff:ffff
175fc8d:ae00::/24fc8d:aeff:ffff:ffff:ffff:ffff:ffff:ffff
176fc8d:af00::/24fc8d:afff:ffff:ffff:ffff:ffff:ffff:ffff
177fc8d:b000::/24fc8d:b0ff:ffff:ffff:ffff:ffff:ffff:ffff
178fc8d:b100::/24fc8d:b1ff:ffff:ffff:ffff:ffff:ffff:ffff
179fc8d:b200::/24fc8d:b2ff:ffff:ffff:ffff:ffff:ffff:ffff
180fc8d:b300::/24fc8d:b3ff:ffff:ffff:ffff:ffff:ffff:ffff
181fc8d:b400::/24fc8d:b4ff:ffff:ffff:ffff:ffff:ffff:ffff
182fc8d:b500::/24fc8d:b5ff:ffff:ffff:ffff:ffff:ffff:ffff
183fc8d:b600::/24fc8d:b6ff:ffff:ffff:ffff:ffff:ffff:ffff
184fc8d:b700::/24fc8d:b7ff:ffff:ffff:ffff:ffff:ffff:ffff
185fc8d:b800::/24fc8d:b8ff:ffff:ffff:ffff:ffff:ffff:ffff
186fc8d:b900::/24fc8d:b9ff:ffff:ffff:ffff:ffff:ffff:ffff
187fc8d:ba00::/24fc8d:baff:ffff:ffff:ffff:ffff:ffff:ffff
188fc8d:bb00::/24fc8d:bbff:ffff:ffff:ffff:ffff:ffff:ffff
189fc8d:bc00::/24fc8d:bcff:ffff:ffff:ffff:ffff:ffff:ffff
190fc8d:bd00::/24fc8d:bdff:ffff:ffff:ffff:ffff:ffff:ffff
191fc8d:be00::/24fc8d:beff:ffff:ffff:ffff:ffff:ffff:ffff
192fc8d:bf00::/24fc8d:bfff:ffff:ffff:ffff:ffff:ffff:ffff
193fc8d:c000::/24fc8d:c0ff:ffff:ffff:ffff:ffff:ffff:ffff
194fc8d:c100::/24fc8d:c1ff:ffff:ffff:ffff:ffff:ffff:ffff
195fc8d:c200::/24fc8d:c2ff:ffff:ffff:ffff:ffff:ffff:ffff
196fc8d:c300::/24fc8d:c3ff:ffff:ffff:ffff:ffff:ffff:ffff
197fc8d:c400::/24fc8d:c4ff:ffff:ffff:ffff:ffff:ffff:ffff
198fc8d:c500::/24fc8d:c5ff:ffff:ffff:ffff:ffff:ffff:ffff
199fc8d:c600::/24fc8d:c6ff:ffff:ffff:ffff:ffff:ffff:ffff
200fc8d:c700::/24fc8d:c7ff:ffff:ffff:ffff:ffff:ffff:ffff
201fc8d:c800::/24fc8d:c8ff:ffff:ffff:ffff:ffff:ffff:ffff
202fc8d:c900::/24fc8d:c9ff:ffff:ffff:ffff:ffff:ffff:ffff
203fc8d:ca00::/24fc8d:caff:ffff:ffff:ffff:ffff:ffff:ffff
204fc8d:cb00::/24fc8d:cbff:ffff:ffff:ffff:ffff:ffff:ffff
205fc8d:cc00::/24fc8d:ccff:ffff:ffff:ffff:ffff:ffff:ffff
206fc8d:cd00::/24fc8d:cdff:ffff:ffff:ffff:ffff:ffff:ffff
207fc8d:ce00::/24fc8d:ceff:ffff:ffff:ffff:ffff:ffff:ffff
208fc8d:cf00::/24fc8d:cfff:ffff:ffff:ffff:ffff:ffff:ffff
209fc8d:d000::/24fc8d:d0ff:ffff:ffff:ffff:ffff:ffff:ffff
210fc8d:d100::/24fc8d:d1ff:ffff:ffff:ffff:ffff:ffff:ffff
211fc8d:d200::/24fc8d:d2ff:ffff:ffff:ffff:ffff:ffff:ffff
212fc8d:d300::/24fc8d:d3ff:ffff:ffff:ffff:ffff:ffff:ffff
213fc8d:d400::/24fc8d:d4ff:ffff:ffff:ffff:ffff:ffff:ffff
214fc8d:d500::/24fc8d:d5ff:ffff:ffff:ffff:ffff:ffff:ffff
215fc8d:d600::/24fc8d:d6ff:ffff:ffff:ffff:ffff:ffff:ffff
216fc8d:d700::/24fc8d:d7ff:ffff:ffff:ffff:ffff:ffff:ffff
217fc8d:d800::/24fc8d:d8ff:ffff:ffff:ffff:ffff:ffff:ffff
218fc8d:d900::/24fc8d:d9ff:ffff:ffff:ffff:ffff:ffff:ffff
219fc8d:da00::/24fc8d:daff:ffff:ffff:ffff:ffff:ffff:ffff
220fc8d:db00::/24fc8d:dbff:ffff:ffff:ffff:ffff:ffff:ffff
221fc8d:dc00::/24fc8d:dcff:ffff:ffff:ffff:ffff:ffff:ffff
222fc8d:dd00::/24fc8d:ddff:ffff:ffff:ffff:ffff:ffff:ffff
223fc8d:de00::/24fc8d:deff:ffff:ffff:ffff:ffff:ffff:ffff
224fc8d:df00::/24fc8d:dfff:ffff:ffff:ffff:ffff:ffff:ffff
225fc8d:e000::/24fc8d:e0ff:ffff:ffff:ffff:ffff:ffff:ffff
226fc8d:e100::/24fc8d:e1ff:ffff:ffff:ffff:ffff:ffff:ffff
227fc8d:e200::/24fc8d:e2ff:ffff:ffff:ffff:ffff:ffff:ffff
228fc8d:e300::/24fc8d:e3ff:ffff:ffff:ffff:ffff:ffff:ffff
229fc8d:e400::/24fc8d:e4ff:ffff:ffff:ffff:ffff:ffff:ffff
230fc8d:e500::/24fc8d:e5ff:ffff:ffff:ffff:ffff:ffff:ffff
231fc8d:e600::/24fc8d:e6ff:ffff:ffff:ffff:ffff:ffff:ffff
232fc8d:e700::/24fc8d:e7ff:ffff:ffff:ffff:ffff:ffff:ffff
233fc8d:e800::/24fc8d:e8ff:ffff:ffff:ffff:ffff:ffff:ffff
234fc8d:e900::/24fc8d:e9ff:ffff:ffff:ffff:ffff:ffff:ffff
235fc8d:ea00::/24fc8d:eaff:ffff:ffff:ffff:ffff:ffff:ffff
236fc8d:eb00::/24fc8d:ebff:ffff:ffff:ffff:ffff:ffff:ffff
237fc8d:ec00::/24fc8d:ecff:ffff:ffff:ffff:ffff:ffff:ffff
238fc8d:ed00::/24fc8d:edff:ffff:ffff:ffff:ffff:ffff:ffff
239fc8d:ee00::/24fc8d:eeff:ffff:ffff:ffff:ffff:ffff:ffff
240fc8d:ef00::/24fc8d:efff:ffff:ffff:ffff:ffff:ffff:ffff
241fc8d:f000::/24fc8d:f0ff:ffff:ffff:ffff:ffff:ffff:ffff
242fc8d:f100::/24fc8d:f1ff:ffff:ffff:ffff:ffff:ffff:ffff
243fc8d:f200::/24fc8d:f2ff:ffff:ffff:ffff:ffff:ffff:ffff
244fc8d:f300::/24fc8d:f3ff:ffff:ffff:ffff:ffff:ffff:ffff
245fc8d:f400::/24fc8d:f4ff:ffff:ffff:ffff:ffff:ffff:ffff
246fc8d:f500::/24fc8d:f5ff:ffff:ffff:ffff:ffff:ffff:ffff
247fc8d:f600::/24fc8d:f6ff:ffff:ffff:ffff:ffff:ffff:ffff
248fc8d:f700::/24fc8d:f7ff:ffff:ffff:ffff:ffff:ffff:ffff
249fc8d:f800::/24fc8d:f8ff:ffff:ffff:ffff:ffff:ffff:ffff
250fc8d:f900::/24fc8d:f9ff:ffff:ffff:ffff:ffff:ffff:ffff
251fc8d:fa00::/24fc8d:faff:ffff:ffff:ffff:ffff:ffff:ffff
252fc8d:fb00::/24fc8d:fbff:ffff:ffff:ffff:ffff:ffff:ffff
253fc8d:fc00::/24fc8d:fcff:ffff:ffff:ffff:ffff:ffff:ffff
254fc8d:fd00::/24fc8d:fdff:ffff:ffff:ffff:ffff:ffff:ffff
255fc8d:fe00::/24fc8d:feff:ffff:ffff:ffff:ffff:ffff:ffff
256fc8d:ff00::/24fc8d: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.