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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
fc8f::/16
First address
fc8f::
Last address
fc8f: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
fc8f: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.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)

fc8f::/16 makes 256 subnets of /24.

Subnets
#SubnetLast address
1fc8f::/24fc8f:ff:ffff:ffff:ffff:ffff:ffff:ffff
2fc8f:100::/24fc8f:1ff:ffff:ffff:ffff:ffff:ffff:ffff
3fc8f:200::/24fc8f:2ff:ffff:ffff:ffff:ffff:ffff:ffff
4fc8f:300::/24fc8f:3ff:ffff:ffff:ffff:ffff:ffff:ffff
5fc8f:400::/24fc8f:4ff:ffff:ffff:ffff:ffff:ffff:ffff
6fc8f:500::/24fc8f:5ff:ffff:ffff:ffff:ffff:ffff:ffff
7fc8f:600::/24fc8f:6ff:ffff:ffff:ffff:ffff:ffff:ffff
8fc8f:700::/24fc8f:7ff:ffff:ffff:ffff:ffff:ffff:ffff
9fc8f:800::/24fc8f:8ff:ffff:ffff:ffff:ffff:ffff:ffff
10fc8f:900::/24fc8f:9ff:ffff:ffff:ffff:ffff:ffff:ffff
11fc8f:a00::/24fc8f:aff:ffff:ffff:ffff:ffff:ffff:ffff
12fc8f:b00::/24fc8f:bff:ffff:ffff:ffff:ffff:ffff:ffff
13fc8f:c00::/24fc8f:cff:ffff:ffff:ffff:ffff:ffff:ffff
14fc8f:d00::/24fc8f:dff:ffff:ffff:ffff:ffff:ffff:ffff
15fc8f:e00::/24fc8f:eff:ffff:ffff:ffff:ffff:ffff:ffff
16fc8f:f00::/24fc8f:fff:ffff:ffff:ffff:ffff:ffff:ffff
17fc8f:1000::/24fc8f:10ff:ffff:ffff:ffff:ffff:ffff:ffff
18fc8f:1100::/24fc8f:11ff:ffff:ffff:ffff:ffff:ffff:ffff
19fc8f:1200::/24fc8f:12ff:ffff:ffff:ffff:ffff:ffff:ffff
20fc8f:1300::/24fc8f:13ff:ffff:ffff:ffff:ffff:ffff:ffff
21fc8f:1400::/24fc8f:14ff:ffff:ffff:ffff:ffff:ffff:ffff
22fc8f:1500::/24fc8f:15ff:ffff:ffff:ffff:ffff:ffff:ffff
23fc8f:1600::/24fc8f:16ff:ffff:ffff:ffff:ffff:ffff:ffff
24fc8f:1700::/24fc8f:17ff:ffff:ffff:ffff:ffff:ffff:ffff
25fc8f:1800::/24fc8f:18ff:ffff:ffff:ffff:ffff:ffff:ffff
26fc8f:1900::/24fc8f:19ff:ffff:ffff:ffff:ffff:ffff:ffff
27fc8f:1a00::/24fc8f:1aff:ffff:ffff:ffff:ffff:ffff:ffff
28fc8f:1b00::/24fc8f:1bff:ffff:ffff:ffff:ffff:ffff:ffff
29fc8f:1c00::/24fc8f:1cff:ffff:ffff:ffff:ffff:ffff:ffff
30fc8f:1d00::/24fc8f:1dff:ffff:ffff:ffff:ffff:ffff:ffff
31fc8f:1e00::/24fc8f:1eff:ffff:ffff:ffff:ffff:ffff:ffff
32fc8f:1f00::/24fc8f:1fff:ffff:ffff:ffff:ffff:ffff:ffff
33fc8f:2000::/24fc8f:20ff:ffff:ffff:ffff:ffff:ffff:ffff
34fc8f:2100::/24fc8f:21ff:ffff:ffff:ffff:ffff:ffff:ffff
35fc8f:2200::/24fc8f:22ff:ffff:ffff:ffff:ffff:ffff:ffff
36fc8f:2300::/24fc8f:23ff:ffff:ffff:ffff:ffff:ffff:ffff
37fc8f:2400::/24fc8f:24ff:ffff:ffff:ffff:ffff:ffff:ffff
38fc8f:2500::/24fc8f:25ff:ffff:ffff:ffff:ffff:ffff:ffff
39fc8f:2600::/24fc8f:26ff:ffff:ffff:ffff:ffff:ffff:ffff
40fc8f:2700::/24fc8f:27ff:ffff:ffff:ffff:ffff:ffff:ffff
41fc8f:2800::/24fc8f:28ff:ffff:ffff:ffff:ffff:ffff:ffff
42fc8f:2900::/24fc8f:29ff:ffff:ffff:ffff:ffff:ffff:ffff
43fc8f:2a00::/24fc8f:2aff:ffff:ffff:ffff:ffff:ffff:ffff
44fc8f:2b00::/24fc8f:2bff:ffff:ffff:ffff:ffff:ffff:ffff
45fc8f:2c00::/24fc8f:2cff:ffff:ffff:ffff:ffff:ffff:ffff
46fc8f:2d00::/24fc8f:2dff:ffff:ffff:ffff:ffff:ffff:ffff
47fc8f:2e00::/24fc8f:2eff:ffff:ffff:ffff:ffff:ffff:ffff
48fc8f:2f00::/24fc8f:2fff:ffff:ffff:ffff:ffff:ffff:ffff
49fc8f:3000::/24fc8f:30ff:ffff:ffff:ffff:ffff:ffff:ffff
50fc8f:3100::/24fc8f:31ff:ffff:ffff:ffff:ffff:ffff:ffff
51fc8f:3200::/24fc8f:32ff:ffff:ffff:ffff:ffff:ffff:ffff
52fc8f:3300::/24fc8f:33ff:ffff:ffff:ffff:ffff:ffff:ffff
53fc8f:3400::/24fc8f:34ff:ffff:ffff:ffff:ffff:ffff:ffff
54fc8f:3500::/24fc8f:35ff:ffff:ffff:ffff:ffff:ffff:ffff
55fc8f:3600::/24fc8f:36ff:ffff:ffff:ffff:ffff:ffff:ffff
56fc8f:3700::/24fc8f:37ff:ffff:ffff:ffff:ffff:ffff:ffff
57fc8f:3800::/24fc8f:38ff:ffff:ffff:ffff:ffff:ffff:ffff
58fc8f:3900::/24fc8f:39ff:ffff:ffff:ffff:ffff:ffff:ffff
59fc8f:3a00::/24fc8f:3aff:ffff:ffff:ffff:ffff:ffff:ffff
60fc8f:3b00::/24fc8f:3bff:ffff:ffff:ffff:ffff:ffff:ffff
61fc8f:3c00::/24fc8f:3cff:ffff:ffff:ffff:ffff:ffff:ffff
62fc8f:3d00::/24fc8f:3dff:ffff:ffff:ffff:ffff:ffff:ffff
63fc8f:3e00::/24fc8f:3eff:ffff:ffff:ffff:ffff:ffff:ffff
64fc8f:3f00::/24fc8f:3fff:ffff:ffff:ffff:ffff:ffff:ffff
65fc8f:4000::/24fc8f:40ff:ffff:ffff:ffff:ffff:ffff:ffff
66fc8f:4100::/24fc8f:41ff:ffff:ffff:ffff:ffff:ffff:ffff
67fc8f:4200::/24fc8f:42ff:ffff:ffff:ffff:ffff:ffff:ffff
68fc8f:4300::/24fc8f:43ff:ffff:ffff:ffff:ffff:ffff:ffff
69fc8f:4400::/24fc8f:44ff:ffff:ffff:ffff:ffff:ffff:ffff
70fc8f:4500::/24fc8f:45ff:ffff:ffff:ffff:ffff:ffff:ffff
71fc8f:4600::/24fc8f:46ff:ffff:ffff:ffff:ffff:ffff:ffff
72fc8f:4700::/24fc8f:47ff:ffff:ffff:ffff:ffff:ffff:ffff
73fc8f:4800::/24fc8f:48ff:ffff:ffff:ffff:ffff:ffff:ffff
74fc8f:4900::/24fc8f:49ff:ffff:ffff:ffff:ffff:ffff:ffff
75fc8f:4a00::/24fc8f:4aff:ffff:ffff:ffff:ffff:ffff:ffff
76fc8f:4b00::/24fc8f:4bff:ffff:ffff:ffff:ffff:ffff:ffff
77fc8f:4c00::/24fc8f:4cff:ffff:ffff:ffff:ffff:ffff:ffff
78fc8f:4d00::/24fc8f:4dff:ffff:ffff:ffff:ffff:ffff:ffff
79fc8f:4e00::/24fc8f:4eff:ffff:ffff:ffff:ffff:ffff:ffff
80fc8f:4f00::/24fc8f:4fff:ffff:ffff:ffff:ffff:ffff:ffff
81fc8f:5000::/24fc8f:50ff:ffff:ffff:ffff:ffff:ffff:ffff
82fc8f:5100::/24fc8f:51ff:ffff:ffff:ffff:ffff:ffff:ffff
83fc8f:5200::/24fc8f:52ff:ffff:ffff:ffff:ffff:ffff:ffff
84fc8f:5300::/24fc8f:53ff:ffff:ffff:ffff:ffff:ffff:ffff
85fc8f:5400::/24fc8f:54ff:ffff:ffff:ffff:ffff:ffff:ffff
86fc8f:5500::/24fc8f:55ff:ffff:ffff:ffff:ffff:ffff:ffff
87fc8f:5600::/24fc8f:56ff:ffff:ffff:ffff:ffff:ffff:ffff
88fc8f:5700::/24fc8f:57ff:ffff:ffff:ffff:ffff:ffff:ffff
89fc8f:5800::/24fc8f:58ff:ffff:ffff:ffff:ffff:ffff:ffff
90fc8f:5900::/24fc8f:59ff:ffff:ffff:ffff:ffff:ffff:ffff
91fc8f:5a00::/24fc8f:5aff:ffff:ffff:ffff:ffff:ffff:ffff
92fc8f:5b00::/24fc8f:5bff:ffff:ffff:ffff:ffff:ffff:ffff
93fc8f:5c00::/24fc8f:5cff:ffff:ffff:ffff:ffff:ffff:ffff
94fc8f:5d00::/24fc8f:5dff:ffff:ffff:ffff:ffff:ffff:ffff
95fc8f:5e00::/24fc8f:5eff:ffff:ffff:ffff:ffff:ffff:ffff
96fc8f:5f00::/24fc8f:5fff:ffff:ffff:ffff:ffff:ffff:ffff
97fc8f:6000::/24fc8f:60ff:ffff:ffff:ffff:ffff:ffff:ffff
98fc8f:6100::/24fc8f:61ff:ffff:ffff:ffff:ffff:ffff:ffff
99fc8f:6200::/24fc8f:62ff:ffff:ffff:ffff:ffff:ffff:ffff
100fc8f:6300::/24fc8f:63ff:ffff:ffff:ffff:ffff:ffff:ffff
101fc8f:6400::/24fc8f:64ff:ffff:ffff:ffff:ffff:ffff:ffff
102fc8f:6500::/24fc8f:65ff:ffff:ffff:ffff:ffff:ffff:ffff
103fc8f:6600::/24fc8f:66ff:ffff:ffff:ffff:ffff:ffff:ffff
104fc8f:6700::/24fc8f:67ff:ffff:ffff:ffff:ffff:ffff:ffff
105fc8f:6800::/24fc8f:68ff:ffff:ffff:ffff:ffff:ffff:ffff
106fc8f:6900::/24fc8f:69ff:ffff:ffff:ffff:ffff:ffff:ffff
107fc8f:6a00::/24fc8f:6aff:ffff:ffff:ffff:ffff:ffff:ffff
108fc8f:6b00::/24fc8f:6bff:ffff:ffff:ffff:ffff:ffff:ffff
109fc8f:6c00::/24fc8f:6cff:ffff:ffff:ffff:ffff:ffff:ffff
110fc8f:6d00::/24fc8f:6dff:ffff:ffff:ffff:ffff:ffff:ffff
111fc8f:6e00::/24fc8f:6eff:ffff:ffff:ffff:ffff:ffff:ffff
112fc8f:6f00::/24fc8f:6fff:ffff:ffff:ffff:ffff:ffff:ffff
113fc8f:7000::/24fc8f:70ff:ffff:ffff:ffff:ffff:ffff:ffff
114fc8f:7100::/24fc8f:71ff:ffff:ffff:ffff:ffff:ffff:ffff
115fc8f:7200::/24fc8f:72ff:ffff:ffff:ffff:ffff:ffff:ffff
116fc8f:7300::/24fc8f:73ff:ffff:ffff:ffff:ffff:ffff:ffff
117fc8f:7400::/24fc8f:74ff:ffff:ffff:ffff:ffff:ffff:ffff
118fc8f:7500::/24fc8f:75ff:ffff:ffff:ffff:ffff:ffff:ffff
119fc8f:7600::/24fc8f:76ff:ffff:ffff:ffff:ffff:ffff:ffff
120fc8f:7700::/24fc8f:77ff:ffff:ffff:ffff:ffff:ffff:ffff
121fc8f:7800::/24fc8f:78ff:ffff:ffff:ffff:ffff:ffff:ffff
122fc8f:7900::/24fc8f:79ff:ffff:ffff:ffff:ffff:ffff:ffff
123fc8f:7a00::/24fc8f:7aff:ffff:ffff:ffff:ffff:ffff:ffff
124fc8f:7b00::/24fc8f:7bff:ffff:ffff:ffff:ffff:ffff:ffff
125fc8f:7c00::/24fc8f:7cff:ffff:ffff:ffff:ffff:ffff:ffff
126fc8f:7d00::/24fc8f:7dff:ffff:ffff:ffff:ffff:ffff:ffff
127fc8f:7e00::/24fc8f:7eff:ffff:ffff:ffff:ffff:ffff:ffff
128fc8f:7f00::/24fc8f:7fff:ffff:ffff:ffff:ffff:ffff:ffff
129fc8f:8000::/24fc8f:80ff:ffff:ffff:ffff:ffff:ffff:ffff
130fc8f:8100::/24fc8f:81ff:ffff:ffff:ffff:ffff:ffff:ffff
131fc8f:8200::/24fc8f:82ff:ffff:ffff:ffff:ffff:ffff:ffff
132fc8f:8300::/24fc8f:83ff:ffff:ffff:ffff:ffff:ffff:ffff
133fc8f:8400::/24fc8f:84ff:ffff:ffff:ffff:ffff:ffff:ffff
134fc8f:8500::/24fc8f:85ff:ffff:ffff:ffff:ffff:ffff:ffff
135fc8f:8600::/24fc8f:86ff:ffff:ffff:ffff:ffff:ffff:ffff
136fc8f:8700::/24fc8f:87ff:ffff:ffff:ffff:ffff:ffff:ffff
137fc8f:8800::/24fc8f:88ff:ffff:ffff:ffff:ffff:ffff:ffff
138fc8f:8900::/24fc8f:89ff:ffff:ffff:ffff:ffff:ffff:ffff
139fc8f:8a00::/24fc8f:8aff:ffff:ffff:ffff:ffff:ffff:ffff
140fc8f:8b00::/24fc8f:8bff:ffff:ffff:ffff:ffff:ffff:ffff
141fc8f:8c00::/24fc8f:8cff:ffff:ffff:ffff:ffff:ffff:ffff
142fc8f:8d00::/24fc8f:8dff:ffff:ffff:ffff:ffff:ffff:ffff
143fc8f:8e00::/24fc8f:8eff:ffff:ffff:ffff:ffff:ffff:ffff
144fc8f:8f00::/24fc8f:8fff:ffff:ffff:ffff:ffff:ffff:ffff
145fc8f:9000::/24fc8f:90ff:ffff:ffff:ffff:ffff:ffff:ffff
146fc8f:9100::/24fc8f:91ff:ffff:ffff:ffff:ffff:ffff:ffff
147fc8f:9200::/24fc8f:92ff:ffff:ffff:ffff:ffff:ffff:ffff
148fc8f:9300::/24fc8f:93ff:ffff:ffff:ffff:ffff:ffff:ffff
149fc8f:9400::/24fc8f:94ff:ffff:ffff:ffff:ffff:ffff:ffff
150fc8f:9500::/24fc8f:95ff:ffff:ffff:ffff:ffff:ffff:ffff
151fc8f:9600::/24fc8f:96ff:ffff:ffff:ffff:ffff:ffff:ffff
152fc8f:9700::/24fc8f:97ff:ffff:ffff:ffff:ffff:ffff:ffff
153fc8f:9800::/24fc8f:98ff:ffff:ffff:ffff:ffff:ffff:ffff
154fc8f:9900::/24fc8f:99ff:ffff:ffff:ffff:ffff:ffff:ffff
155fc8f:9a00::/24fc8f:9aff:ffff:ffff:ffff:ffff:ffff:ffff
156fc8f:9b00::/24fc8f:9bff:ffff:ffff:ffff:ffff:ffff:ffff
157fc8f:9c00::/24fc8f:9cff:ffff:ffff:ffff:ffff:ffff:ffff
158fc8f:9d00::/24fc8f:9dff:ffff:ffff:ffff:ffff:ffff:ffff
159fc8f:9e00::/24fc8f:9eff:ffff:ffff:ffff:ffff:ffff:ffff
160fc8f:9f00::/24fc8f:9fff:ffff:ffff:ffff:ffff:ffff:ffff
161fc8f:a000::/24fc8f:a0ff:ffff:ffff:ffff:ffff:ffff:ffff
162fc8f:a100::/24fc8f:a1ff:ffff:ffff:ffff:ffff:ffff:ffff
163fc8f:a200::/24fc8f:a2ff:ffff:ffff:ffff:ffff:ffff:ffff
164fc8f:a300::/24fc8f:a3ff:ffff:ffff:ffff:ffff:ffff:ffff
165fc8f:a400::/24fc8f:a4ff:ffff:ffff:ffff:ffff:ffff:ffff
166fc8f:a500::/24fc8f:a5ff:ffff:ffff:ffff:ffff:ffff:ffff
167fc8f:a600::/24fc8f:a6ff:ffff:ffff:ffff:ffff:ffff:ffff
168fc8f:a700::/24fc8f:a7ff:ffff:ffff:ffff:ffff:ffff:ffff
169fc8f:a800::/24fc8f:a8ff:ffff:ffff:ffff:ffff:ffff:ffff
170fc8f:a900::/24fc8f:a9ff:ffff:ffff:ffff:ffff:ffff:ffff
171fc8f:aa00::/24fc8f:aaff:ffff:ffff:ffff:ffff:ffff:ffff
172fc8f:ab00::/24fc8f:abff:ffff:ffff:ffff:ffff:ffff:ffff
173fc8f:ac00::/24fc8f:acff:ffff:ffff:ffff:ffff:ffff:ffff
174fc8f:ad00::/24fc8f:adff:ffff:ffff:ffff:ffff:ffff:ffff
175fc8f:ae00::/24fc8f:aeff:ffff:ffff:ffff:ffff:ffff:ffff
176fc8f:af00::/24fc8f:afff:ffff:ffff:ffff:ffff:ffff:ffff
177fc8f:b000::/24fc8f:b0ff:ffff:ffff:ffff:ffff:ffff:ffff
178fc8f:b100::/24fc8f:b1ff:ffff:ffff:ffff:ffff:ffff:ffff
179fc8f:b200::/24fc8f:b2ff:ffff:ffff:ffff:ffff:ffff:ffff
180fc8f:b300::/24fc8f:b3ff:ffff:ffff:ffff:ffff:ffff:ffff
181fc8f:b400::/24fc8f:b4ff:ffff:ffff:ffff:ffff:ffff:ffff
182fc8f:b500::/24fc8f:b5ff:ffff:ffff:ffff:ffff:ffff:ffff
183fc8f:b600::/24fc8f:b6ff:ffff:ffff:ffff:ffff:ffff:ffff
184fc8f:b700::/24fc8f:b7ff:ffff:ffff:ffff:ffff:ffff:ffff
185fc8f:b800::/24fc8f:b8ff:ffff:ffff:ffff:ffff:ffff:ffff
186fc8f:b900::/24fc8f:b9ff:ffff:ffff:ffff:ffff:ffff:ffff
187fc8f:ba00::/24fc8f:baff:ffff:ffff:ffff:ffff:ffff:ffff
188fc8f:bb00::/24fc8f:bbff:ffff:ffff:ffff:ffff:ffff:ffff
189fc8f:bc00::/24fc8f:bcff:ffff:ffff:ffff:ffff:ffff:ffff
190fc8f:bd00::/24fc8f:bdff:ffff:ffff:ffff:ffff:ffff:ffff
191fc8f:be00::/24fc8f:beff:ffff:ffff:ffff:ffff:ffff:ffff
192fc8f:bf00::/24fc8f:bfff:ffff:ffff:ffff:ffff:ffff:ffff
193fc8f:c000::/24fc8f:c0ff:ffff:ffff:ffff:ffff:ffff:ffff
194fc8f:c100::/24fc8f:c1ff:ffff:ffff:ffff:ffff:ffff:ffff
195fc8f:c200::/24fc8f:c2ff:ffff:ffff:ffff:ffff:ffff:ffff
196fc8f:c300::/24fc8f:c3ff:ffff:ffff:ffff:ffff:ffff:ffff
197fc8f:c400::/24fc8f:c4ff:ffff:ffff:ffff:ffff:ffff:ffff
198fc8f:c500::/24fc8f:c5ff:ffff:ffff:ffff:ffff:ffff:ffff
199fc8f:c600::/24fc8f:c6ff:ffff:ffff:ffff:ffff:ffff:ffff
200fc8f:c700::/24fc8f:c7ff:ffff:ffff:ffff:ffff:ffff:ffff
201fc8f:c800::/24fc8f:c8ff:ffff:ffff:ffff:ffff:ffff:ffff
202fc8f:c900::/24fc8f:c9ff:ffff:ffff:ffff:ffff:ffff:ffff
203fc8f:ca00::/24fc8f:caff:ffff:ffff:ffff:ffff:ffff:ffff
204fc8f:cb00::/24fc8f:cbff:ffff:ffff:ffff:ffff:ffff:ffff
205fc8f:cc00::/24fc8f:ccff:ffff:ffff:ffff:ffff:ffff:ffff
206fc8f:cd00::/24fc8f:cdff:ffff:ffff:ffff:ffff:ffff:ffff
207fc8f:ce00::/24fc8f:ceff:ffff:ffff:ffff:ffff:ffff:ffff
208fc8f:cf00::/24fc8f:cfff:ffff:ffff:ffff:ffff:ffff:ffff
209fc8f:d000::/24fc8f:d0ff:ffff:ffff:ffff:ffff:ffff:ffff
210fc8f:d100::/24fc8f:d1ff:ffff:ffff:ffff:ffff:ffff:ffff
211fc8f:d200::/24fc8f:d2ff:ffff:ffff:ffff:ffff:ffff:ffff
212fc8f:d300::/24fc8f:d3ff:ffff:ffff:ffff:ffff:ffff:ffff
213fc8f:d400::/24fc8f:d4ff:ffff:ffff:ffff:ffff:ffff:ffff
214fc8f:d500::/24fc8f:d5ff:ffff:ffff:ffff:ffff:ffff:ffff
215fc8f:d600::/24fc8f:d6ff:ffff:ffff:ffff:ffff:ffff:ffff
216fc8f:d700::/24fc8f:d7ff:ffff:ffff:ffff:ffff:ffff:ffff
217fc8f:d800::/24fc8f:d8ff:ffff:ffff:ffff:ffff:ffff:ffff
218fc8f:d900::/24fc8f:d9ff:ffff:ffff:ffff:ffff:ffff:ffff
219fc8f:da00::/24fc8f:daff:ffff:ffff:ffff:ffff:ffff:ffff
220fc8f:db00::/24fc8f:dbff:ffff:ffff:ffff:ffff:ffff:ffff
221fc8f:dc00::/24fc8f:dcff:ffff:ffff:ffff:ffff:ffff:ffff
222fc8f:dd00::/24fc8f:ddff:ffff:ffff:ffff:ffff:ffff:ffff
223fc8f:de00::/24fc8f:deff:ffff:ffff:ffff:ffff:ffff:ffff
224fc8f:df00::/24fc8f:dfff:ffff:ffff:ffff:ffff:ffff:ffff
225fc8f:e000::/24fc8f:e0ff:ffff:ffff:ffff:ffff:ffff:ffff
226fc8f:e100::/24fc8f:e1ff:ffff:ffff:ffff:ffff:ffff:ffff
227fc8f:e200::/24fc8f:e2ff:ffff:ffff:ffff:ffff:ffff:ffff
228fc8f:e300::/24fc8f:e3ff:ffff:ffff:ffff:ffff:ffff:ffff
229fc8f:e400::/24fc8f:e4ff:ffff:ffff:ffff:ffff:ffff:ffff
230fc8f:e500::/24fc8f:e5ff:ffff:ffff:ffff:ffff:ffff:ffff
231fc8f:e600::/24fc8f:e6ff:ffff:ffff:ffff:ffff:ffff:ffff
232fc8f:e700::/24fc8f:e7ff:ffff:ffff:ffff:ffff:ffff:ffff
233fc8f:e800::/24fc8f:e8ff:ffff:ffff:ffff:ffff:ffff:ffff
234fc8f:e900::/24fc8f:e9ff:ffff:ffff:ffff:ffff:ffff:ffff
235fc8f:ea00::/24fc8f:eaff:ffff:ffff:ffff:ffff:ffff:ffff
236fc8f:eb00::/24fc8f:ebff:ffff:ffff:ffff:ffff:ffff:ffff
237fc8f:ec00::/24fc8f:ecff:ffff:ffff:ffff:ffff:ffff:ffff
238fc8f:ed00::/24fc8f:edff:ffff:ffff:ffff:ffff:ffff:ffff
239fc8f:ee00::/24fc8f:eeff:ffff:ffff:ffff:ffff:ffff:ffff
240fc8f:ef00::/24fc8f:efff:ffff:ffff:ffff:ffff:ffff:ffff
241fc8f:f000::/24fc8f:f0ff:ffff:ffff:ffff:ffff:ffff:ffff
242fc8f:f100::/24fc8f:f1ff:ffff:ffff:ffff:ffff:ffff:ffff
243fc8f:f200::/24fc8f:f2ff:ffff:ffff:ffff:ffff:ffff:ffff
244fc8f:f300::/24fc8f:f3ff:ffff:ffff:ffff:ffff:ffff:ffff
245fc8f:f400::/24fc8f:f4ff:ffff:ffff:ffff:ffff:ffff:ffff
246fc8f:f500::/24fc8f:f5ff:ffff:ffff:ffff:ffff:ffff:ffff
247fc8f:f600::/24fc8f:f6ff:ffff:ffff:ffff:ffff:ffff:ffff
248fc8f:f700::/24fc8f:f7ff:ffff:ffff:ffff:ffff:ffff:ffff
249fc8f:f800::/24fc8f:f8ff:ffff:ffff:ffff:ffff:ffff:ffff
250fc8f:f900::/24fc8f:f9ff:ffff:ffff:ffff:ffff:ffff:ffff
251fc8f:fa00::/24fc8f:faff:ffff:ffff:ffff:ffff:ffff:ffff
252fc8f:fb00::/24fc8f:fbff:ffff:ffff:ffff:ffff:ffff:ffff
253fc8f:fc00::/24fc8f:fcff:ffff:ffff:ffff:ffff:ffff:ffff
254fc8f:fd00::/24fc8f:fdff:ffff:ffff:ffff:ffff:ffff:ffff
255fc8f:fe00::/24fc8f:feff:ffff:ffff:ffff:ffff:ffff:ffff
256fc8f:ff00::/24fc8f: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.