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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/8
Addresses2^120
/64 networks2^56
Network
2700::/8
First address
2700::
Last address
27ff:ffff:ffff:ffff:ffff:ffff:ffff:ffff
Addresses
1,329,227,995,784,915,872,903,807,060,280,344,576 (2^120)
/64 networks (LANs)
72,057,594,037,927,936 (2^56)
Full form
2700:0000:0000:0000:0000:0000:0000:0000
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zone
7.2.ip6.arpa
Split into smaller subnets/24
/9 (2)/10 (4)/11 (8)/12 (16)/16 (256)/20 (4,096)/24 (65,536)

2700::/8 makes 65,536 subnets of /24; the first 256 are listed.

Subnets
#SubnetLast address
12700::/242700:ff:ffff:ffff:ffff:ffff:ffff:ffff
22700:100::/242700:1ff:ffff:ffff:ffff:ffff:ffff:ffff
32700:200::/242700:2ff:ffff:ffff:ffff:ffff:ffff:ffff
42700:300::/242700:3ff:ffff:ffff:ffff:ffff:ffff:ffff
52700:400::/242700:4ff:ffff:ffff:ffff:ffff:ffff:ffff
62700:500::/242700:5ff:ffff:ffff:ffff:ffff:ffff:ffff
72700:600::/242700:6ff:ffff:ffff:ffff:ffff:ffff:ffff
82700:700::/242700:7ff:ffff:ffff:ffff:ffff:ffff:ffff
92700:800::/242700:8ff:ffff:ffff:ffff:ffff:ffff:ffff
102700:900::/242700:9ff:ffff:ffff:ffff:ffff:ffff:ffff
112700:a00::/242700:aff:ffff:ffff:ffff:ffff:ffff:ffff
122700:b00::/242700:bff:ffff:ffff:ffff:ffff:ffff:ffff
132700:c00::/242700:cff:ffff:ffff:ffff:ffff:ffff:ffff
142700:d00::/242700:dff:ffff:ffff:ffff:ffff:ffff:ffff
152700:e00::/242700:eff:ffff:ffff:ffff:ffff:ffff:ffff
162700:f00::/242700:fff:ffff:ffff:ffff:ffff:ffff:ffff
172700:1000::/242700:10ff:ffff:ffff:ffff:ffff:ffff:ffff
182700:1100::/242700:11ff:ffff:ffff:ffff:ffff:ffff:ffff
192700:1200::/242700:12ff:ffff:ffff:ffff:ffff:ffff:ffff
202700:1300::/242700:13ff:ffff:ffff:ffff:ffff:ffff:ffff
212700:1400::/242700:14ff:ffff:ffff:ffff:ffff:ffff:ffff
222700:1500::/242700:15ff:ffff:ffff:ffff:ffff:ffff:ffff
232700:1600::/242700:16ff:ffff:ffff:ffff:ffff:ffff:ffff
242700:1700::/242700:17ff:ffff:ffff:ffff:ffff:ffff:ffff
252700:1800::/242700:18ff:ffff:ffff:ffff:ffff:ffff:ffff
262700:1900::/242700:19ff:ffff:ffff:ffff:ffff:ffff:ffff
272700:1a00::/242700:1aff:ffff:ffff:ffff:ffff:ffff:ffff
282700:1b00::/242700:1bff:ffff:ffff:ffff:ffff:ffff:ffff
292700:1c00::/242700:1cff:ffff:ffff:ffff:ffff:ffff:ffff
302700:1d00::/242700:1dff:ffff:ffff:ffff:ffff:ffff:ffff
312700:1e00::/242700:1eff:ffff:ffff:ffff:ffff:ffff:ffff
322700:1f00::/242700:1fff:ffff:ffff:ffff:ffff:ffff:ffff
332700:2000::/242700:20ff:ffff:ffff:ffff:ffff:ffff:ffff
342700:2100::/242700:21ff:ffff:ffff:ffff:ffff:ffff:ffff
352700:2200::/242700:22ff:ffff:ffff:ffff:ffff:ffff:ffff
362700:2300::/242700:23ff:ffff:ffff:ffff:ffff:ffff:ffff
372700:2400::/242700:24ff:ffff:ffff:ffff:ffff:ffff:ffff
382700:2500::/242700:25ff:ffff:ffff:ffff:ffff:ffff:ffff
392700:2600::/242700:26ff:ffff:ffff:ffff:ffff:ffff:ffff
402700:2700::/242700:27ff:ffff:ffff:ffff:ffff:ffff:ffff
412700:2800::/242700:28ff:ffff:ffff:ffff:ffff:ffff:ffff
422700:2900::/242700:29ff:ffff:ffff:ffff:ffff:ffff:ffff
432700:2a00::/242700:2aff:ffff:ffff:ffff:ffff:ffff:ffff
442700:2b00::/242700:2bff:ffff:ffff:ffff:ffff:ffff:ffff
452700:2c00::/242700:2cff:ffff:ffff:ffff:ffff:ffff:ffff
462700:2d00::/242700:2dff:ffff:ffff:ffff:ffff:ffff:ffff
472700:2e00::/242700:2eff:ffff:ffff:ffff:ffff:ffff:ffff
482700:2f00::/242700:2fff:ffff:ffff:ffff:ffff:ffff:ffff
492700:3000::/242700:30ff:ffff:ffff:ffff:ffff:ffff:ffff
502700:3100::/242700:31ff:ffff:ffff:ffff:ffff:ffff:ffff
512700:3200::/242700:32ff:ffff:ffff:ffff:ffff:ffff:ffff
522700:3300::/242700:33ff:ffff:ffff:ffff:ffff:ffff:ffff
532700:3400::/242700:34ff:ffff:ffff:ffff:ffff:ffff:ffff
542700:3500::/242700:35ff:ffff:ffff:ffff:ffff:ffff:ffff
552700:3600::/242700:36ff:ffff:ffff:ffff:ffff:ffff:ffff
562700:3700::/242700:37ff:ffff:ffff:ffff:ffff:ffff:ffff
572700:3800::/242700:38ff:ffff:ffff:ffff:ffff:ffff:ffff
582700:3900::/242700:39ff:ffff:ffff:ffff:ffff:ffff:ffff
592700:3a00::/242700:3aff:ffff:ffff:ffff:ffff:ffff:ffff
602700:3b00::/242700:3bff:ffff:ffff:ffff:ffff:ffff:ffff
612700:3c00::/242700:3cff:ffff:ffff:ffff:ffff:ffff:ffff
622700:3d00::/242700:3dff:ffff:ffff:ffff:ffff:ffff:ffff
632700:3e00::/242700:3eff:ffff:ffff:ffff:ffff:ffff:ffff
642700:3f00::/242700:3fff:ffff:ffff:ffff:ffff:ffff:ffff
652700:4000::/242700:40ff:ffff:ffff:ffff:ffff:ffff:ffff
662700:4100::/242700:41ff:ffff:ffff:ffff:ffff:ffff:ffff
672700:4200::/242700:42ff:ffff:ffff:ffff:ffff:ffff:ffff
682700:4300::/242700:43ff:ffff:ffff:ffff:ffff:ffff:ffff
692700:4400::/242700:44ff:ffff:ffff:ffff:ffff:ffff:ffff
702700:4500::/242700:45ff:ffff:ffff:ffff:ffff:ffff:ffff
712700:4600::/242700:46ff:ffff:ffff:ffff:ffff:ffff:ffff
722700:4700::/242700:47ff:ffff:ffff:ffff:ffff:ffff:ffff
732700:4800::/242700:48ff:ffff:ffff:ffff:ffff:ffff:ffff
742700:4900::/242700:49ff:ffff:ffff:ffff:ffff:ffff:ffff
752700:4a00::/242700:4aff:ffff:ffff:ffff:ffff:ffff:ffff
762700:4b00::/242700:4bff:ffff:ffff:ffff:ffff:ffff:ffff
772700:4c00::/242700:4cff:ffff:ffff:ffff:ffff:ffff:ffff
782700:4d00::/242700:4dff:ffff:ffff:ffff:ffff:ffff:ffff
792700:4e00::/242700:4eff:ffff:ffff:ffff:ffff:ffff:ffff
802700:4f00::/242700:4fff:ffff:ffff:ffff:ffff:ffff:ffff
812700:5000::/242700:50ff:ffff:ffff:ffff:ffff:ffff:ffff
822700:5100::/242700:51ff:ffff:ffff:ffff:ffff:ffff:ffff
832700:5200::/242700:52ff:ffff:ffff:ffff:ffff:ffff:ffff
842700:5300::/242700:53ff:ffff:ffff:ffff:ffff:ffff:ffff
852700:5400::/242700:54ff:ffff:ffff:ffff:ffff:ffff:ffff
862700:5500::/242700:55ff:ffff:ffff:ffff:ffff:ffff:ffff
872700:5600::/242700:56ff:ffff:ffff:ffff:ffff:ffff:ffff
882700:5700::/242700:57ff:ffff:ffff:ffff:ffff:ffff:ffff
892700:5800::/242700:58ff:ffff:ffff:ffff:ffff:ffff:ffff
902700:5900::/242700:59ff:ffff:ffff:ffff:ffff:ffff:ffff
912700:5a00::/242700:5aff:ffff:ffff:ffff:ffff:ffff:ffff
922700:5b00::/242700:5bff:ffff:ffff:ffff:ffff:ffff:ffff
932700:5c00::/242700:5cff:ffff:ffff:ffff:ffff:ffff:ffff
942700:5d00::/242700:5dff:ffff:ffff:ffff:ffff:ffff:ffff
952700:5e00::/242700:5eff:ffff:ffff:ffff:ffff:ffff:ffff
962700:5f00::/242700:5fff:ffff:ffff:ffff:ffff:ffff:ffff
972700:6000::/242700:60ff:ffff:ffff:ffff:ffff:ffff:ffff
982700:6100::/242700:61ff:ffff:ffff:ffff:ffff:ffff:ffff
992700:6200::/242700:62ff:ffff:ffff:ffff:ffff:ffff:ffff
1002700:6300::/242700:63ff:ffff:ffff:ffff:ffff:ffff:ffff
1012700:6400::/242700:64ff:ffff:ffff:ffff:ffff:ffff:ffff
1022700:6500::/242700:65ff:ffff:ffff:ffff:ffff:ffff:ffff
1032700:6600::/242700:66ff:ffff:ffff:ffff:ffff:ffff:ffff
1042700:6700::/242700:67ff:ffff:ffff:ffff:ffff:ffff:ffff
1052700:6800::/242700:68ff:ffff:ffff:ffff:ffff:ffff:ffff
1062700:6900::/242700:69ff:ffff:ffff:ffff:ffff:ffff:ffff
1072700:6a00::/242700:6aff:ffff:ffff:ffff:ffff:ffff:ffff
1082700:6b00::/242700:6bff:ffff:ffff:ffff:ffff:ffff:ffff
1092700:6c00::/242700:6cff:ffff:ffff:ffff:ffff:ffff:ffff
1102700:6d00::/242700:6dff:ffff:ffff:ffff:ffff:ffff:ffff
1112700:6e00::/242700:6eff:ffff:ffff:ffff:ffff:ffff:ffff
1122700:6f00::/242700:6fff:ffff:ffff:ffff:ffff:ffff:ffff
1132700:7000::/242700:70ff:ffff:ffff:ffff:ffff:ffff:ffff
1142700:7100::/242700:71ff:ffff:ffff:ffff:ffff:ffff:ffff
1152700:7200::/242700:72ff:ffff:ffff:ffff:ffff:ffff:ffff
1162700:7300::/242700:73ff:ffff:ffff:ffff:ffff:ffff:ffff
1172700:7400::/242700:74ff:ffff:ffff:ffff:ffff:ffff:ffff
1182700:7500::/242700:75ff:ffff:ffff:ffff:ffff:ffff:ffff
1192700:7600::/242700:76ff:ffff:ffff:ffff:ffff:ffff:ffff
1202700:7700::/242700:77ff:ffff:ffff:ffff:ffff:ffff:ffff
1212700:7800::/242700:78ff:ffff:ffff:ffff:ffff:ffff:ffff
1222700:7900::/242700:79ff:ffff:ffff:ffff:ffff:ffff:ffff
1232700:7a00::/242700:7aff:ffff:ffff:ffff:ffff:ffff:ffff
1242700:7b00::/242700:7bff:ffff:ffff:ffff:ffff:ffff:ffff
1252700:7c00::/242700:7cff:ffff:ffff:ffff:ffff:ffff:ffff
1262700:7d00::/242700:7dff:ffff:ffff:ffff:ffff:ffff:ffff
1272700:7e00::/242700:7eff:ffff:ffff:ffff:ffff:ffff:ffff
1282700:7f00::/242700:7fff:ffff:ffff:ffff:ffff:ffff:ffff
1292700:8000::/242700:80ff:ffff:ffff:ffff:ffff:ffff:ffff
1302700:8100::/242700:81ff:ffff:ffff:ffff:ffff:ffff:ffff
1312700:8200::/242700:82ff:ffff:ffff:ffff:ffff:ffff:ffff
1322700:8300::/242700:83ff:ffff:ffff:ffff:ffff:ffff:ffff
1332700:8400::/242700:84ff:ffff:ffff:ffff:ffff:ffff:ffff
1342700:8500::/242700:85ff:ffff:ffff:ffff:ffff:ffff:ffff
1352700:8600::/242700:86ff:ffff:ffff:ffff:ffff:ffff:ffff
1362700:8700::/242700:87ff:ffff:ffff:ffff:ffff:ffff:ffff
1372700:8800::/242700:88ff:ffff:ffff:ffff:ffff:ffff:ffff
1382700:8900::/242700:89ff:ffff:ffff:ffff:ffff:ffff:ffff
1392700:8a00::/242700:8aff:ffff:ffff:ffff:ffff:ffff:ffff
1402700:8b00::/242700:8bff:ffff:ffff:ffff:ffff:ffff:ffff
1412700:8c00::/242700:8cff:ffff:ffff:ffff:ffff:ffff:ffff
1422700:8d00::/242700:8dff:ffff:ffff:ffff:ffff:ffff:ffff
1432700:8e00::/242700:8eff:ffff:ffff:ffff:ffff:ffff:ffff
1442700:8f00::/242700:8fff:ffff:ffff:ffff:ffff:ffff:ffff
1452700:9000::/242700:90ff:ffff:ffff:ffff:ffff:ffff:ffff
1462700:9100::/242700:91ff:ffff:ffff:ffff:ffff:ffff:ffff
1472700:9200::/242700:92ff:ffff:ffff:ffff:ffff:ffff:ffff
1482700:9300::/242700:93ff:ffff:ffff:ffff:ffff:ffff:ffff
1492700:9400::/242700:94ff:ffff:ffff:ffff:ffff:ffff:ffff
1502700:9500::/242700:95ff:ffff:ffff:ffff:ffff:ffff:ffff
1512700:9600::/242700:96ff:ffff:ffff:ffff:ffff:ffff:ffff
1522700:9700::/242700:97ff:ffff:ffff:ffff:ffff:ffff:ffff
1532700:9800::/242700:98ff:ffff:ffff:ffff:ffff:ffff:ffff
1542700:9900::/242700:99ff:ffff:ffff:ffff:ffff:ffff:ffff
1552700:9a00::/242700:9aff:ffff:ffff:ffff:ffff:ffff:ffff
1562700:9b00::/242700:9bff:ffff:ffff:ffff:ffff:ffff:ffff
1572700:9c00::/242700:9cff:ffff:ffff:ffff:ffff:ffff:ffff
1582700:9d00::/242700:9dff:ffff:ffff:ffff:ffff:ffff:ffff
1592700:9e00::/242700:9eff:ffff:ffff:ffff:ffff:ffff:ffff
1602700:9f00::/242700:9fff:ffff:ffff:ffff:ffff:ffff:ffff
1612700:a000::/242700:a0ff:ffff:ffff:ffff:ffff:ffff:ffff
1622700:a100::/242700:a1ff:ffff:ffff:ffff:ffff:ffff:ffff
1632700:a200::/242700:a2ff:ffff:ffff:ffff:ffff:ffff:ffff
1642700:a300::/242700:a3ff:ffff:ffff:ffff:ffff:ffff:ffff
1652700:a400::/242700:a4ff:ffff:ffff:ffff:ffff:ffff:ffff
1662700:a500::/242700:a5ff:ffff:ffff:ffff:ffff:ffff:ffff
1672700:a600::/242700:a6ff:ffff:ffff:ffff:ffff:ffff:ffff
1682700:a700::/242700:a7ff:ffff:ffff:ffff:ffff:ffff:ffff
1692700:a800::/242700:a8ff:ffff:ffff:ffff:ffff:ffff:ffff
1702700:a900::/242700:a9ff:ffff:ffff:ffff:ffff:ffff:ffff
1712700:aa00::/242700:aaff:ffff:ffff:ffff:ffff:ffff:ffff
1722700:ab00::/242700:abff:ffff:ffff:ffff:ffff:ffff:ffff
1732700:ac00::/242700:acff:ffff:ffff:ffff:ffff:ffff:ffff
1742700:ad00::/242700:adff:ffff:ffff:ffff:ffff:ffff:ffff
1752700:ae00::/242700:aeff:ffff:ffff:ffff:ffff:ffff:ffff
1762700:af00::/242700:afff:ffff:ffff:ffff:ffff:ffff:ffff
1772700:b000::/242700:b0ff:ffff:ffff:ffff:ffff:ffff:ffff
1782700:b100::/242700:b1ff:ffff:ffff:ffff:ffff:ffff:ffff
1792700:b200::/242700:b2ff:ffff:ffff:ffff:ffff:ffff:ffff
1802700:b300::/242700:b3ff:ffff:ffff:ffff:ffff:ffff:ffff
1812700:b400::/242700:b4ff:ffff:ffff:ffff:ffff:ffff:ffff
1822700:b500::/242700:b5ff:ffff:ffff:ffff:ffff:ffff:ffff
1832700:b600::/242700:b6ff:ffff:ffff:ffff:ffff:ffff:ffff
1842700:b700::/242700:b7ff:ffff:ffff:ffff:ffff:ffff:ffff
1852700:b800::/242700:b8ff:ffff:ffff:ffff:ffff:ffff:ffff
1862700:b900::/242700:b9ff:ffff:ffff:ffff:ffff:ffff:ffff
1872700:ba00::/242700:baff:ffff:ffff:ffff:ffff:ffff:ffff
1882700:bb00::/242700:bbff:ffff:ffff:ffff:ffff:ffff:ffff
1892700:bc00::/242700:bcff:ffff:ffff:ffff:ffff:ffff:ffff
1902700:bd00::/242700:bdff:ffff:ffff:ffff:ffff:ffff:ffff
1912700:be00::/242700:beff:ffff:ffff:ffff:ffff:ffff:ffff
1922700:bf00::/242700:bfff:ffff:ffff:ffff:ffff:ffff:ffff
1932700:c000::/242700:c0ff:ffff:ffff:ffff:ffff:ffff:ffff
1942700:c100::/242700:c1ff:ffff:ffff:ffff:ffff:ffff:ffff
1952700:c200::/242700:c2ff:ffff:ffff:ffff:ffff:ffff:ffff
1962700:c300::/242700:c3ff:ffff:ffff:ffff:ffff:ffff:ffff
1972700:c400::/242700:c4ff:ffff:ffff:ffff:ffff:ffff:ffff
1982700:c500::/242700:c5ff:ffff:ffff:ffff:ffff:ffff:ffff
1992700:c600::/242700:c6ff:ffff:ffff:ffff:ffff:ffff:ffff
2002700:c700::/242700:c7ff:ffff:ffff:ffff:ffff:ffff:ffff
2012700:c800::/242700:c8ff:ffff:ffff:ffff:ffff:ffff:ffff
2022700:c900::/242700:c9ff:ffff:ffff:ffff:ffff:ffff:ffff
2032700:ca00::/242700:caff:ffff:ffff:ffff:ffff:ffff:ffff
2042700:cb00::/242700:cbff:ffff:ffff:ffff:ffff:ffff:ffff
2052700:cc00::/242700:ccff:ffff:ffff:ffff:ffff:ffff:ffff
2062700:cd00::/242700:cdff:ffff:ffff:ffff:ffff:ffff:ffff
2072700:ce00::/242700:ceff:ffff:ffff:ffff:ffff:ffff:ffff
2082700:cf00::/242700:cfff:ffff:ffff:ffff:ffff:ffff:ffff
2092700:d000::/242700:d0ff:ffff:ffff:ffff:ffff:ffff:ffff
2102700:d100::/242700:d1ff:ffff:ffff:ffff:ffff:ffff:ffff
2112700:d200::/242700:d2ff:ffff:ffff:ffff:ffff:ffff:ffff
2122700:d300::/242700:d3ff:ffff:ffff:ffff:ffff:ffff:ffff
2132700:d400::/242700:d4ff:ffff:ffff:ffff:ffff:ffff:ffff
2142700:d500::/242700:d5ff:ffff:ffff:ffff:ffff:ffff:ffff
2152700:d600::/242700:d6ff:ffff:ffff:ffff:ffff:ffff:ffff
2162700:d700::/242700:d7ff:ffff:ffff:ffff:ffff:ffff:ffff
2172700:d800::/242700:d8ff:ffff:ffff:ffff:ffff:ffff:ffff
2182700:d900::/242700:d9ff:ffff:ffff:ffff:ffff:ffff:ffff
2192700:da00::/242700:daff:ffff:ffff:ffff:ffff:ffff:ffff
2202700:db00::/242700:dbff:ffff:ffff:ffff:ffff:ffff:ffff
2212700:dc00::/242700:dcff:ffff:ffff:ffff:ffff:ffff:ffff
2222700:dd00::/242700:ddff:ffff:ffff:ffff:ffff:ffff:ffff
2232700:de00::/242700:deff:ffff:ffff:ffff:ffff:ffff:ffff
2242700:df00::/242700:dfff:ffff:ffff:ffff:ffff:ffff:ffff
2252700:e000::/242700:e0ff:ffff:ffff:ffff:ffff:ffff:ffff
2262700:e100::/242700:e1ff:ffff:ffff:ffff:ffff:ffff:ffff
2272700:e200::/242700:e2ff:ffff:ffff:ffff:ffff:ffff:ffff
2282700:e300::/242700:e3ff:ffff:ffff:ffff:ffff:ffff:ffff
2292700:e400::/242700:e4ff:ffff:ffff:ffff:ffff:ffff:ffff
2302700:e500::/242700:e5ff:ffff:ffff:ffff:ffff:ffff:ffff
2312700:e600::/242700:e6ff:ffff:ffff:ffff:ffff:ffff:ffff
2322700:e700::/242700:e7ff:ffff:ffff:ffff:ffff:ffff:ffff
2332700:e800::/242700:e8ff:ffff:ffff:ffff:ffff:ffff:ffff
2342700:e900::/242700:e9ff:ffff:ffff:ffff:ffff:ffff:ffff
2352700:ea00::/242700:eaff:ffff:ffff:ffff:ffff:ffff:ffff
2362700:eb00::/242700:ebff:ffff:ffff:ffff:ffff:ffff:ffff
2372700:ec00::/242700:ecff:ffff:ffff:ffff:ffff:ffff:ffff
2382700:ed00::/242700:edff:ffff:ffff:ffff:ffff:ffff:ffff
2392700:ee00::/242700:eeff:ffff:ffff:ffff:ffff:ffff:ffff
2402700:ef00::/242700:efff:ffff:ffff:ffff:ffff:ffff:ffff
2412700:f000::/242700:f0ff:ffff:ffff:ffff:ffff:ffff:ffff
2422700:f100::/242700:f1ff:ffff:ffff:ffff:ffff:ffff:ffff
2432700:f200::/242700:f2ff:ffff:ffff:ffff:ffff:ffff:ffff
2442700:f300::/242700:f3ff:ffff:ffff:ffff:ffff:ffff:ffff
2452700:f400::/242700:f4ff:ffff:ffff:ffff:ffff:ffff:ffff
2462700:f500::/242700:f5ff:ffff:ffff:ffff:ffff:ffff:ffff
2472700:f600::/242700:f6ff:ffff:ffff:ffff:ffff:ffff:ffff
2482700:f700::/242700:f7ff:ffff:ffff:ffff:ffff:ffff:ffff
2492700:f800::/242700:f8ff:ffff:ffff:ffff:ffff:ffff:ffff
2502700:f900::/242700:f9ff:ffff:ffff:ffff:ffff:ffff:ffff
2512700:fa00::/242700:faff:ffff:ffff:ffff:ffff:ffff:ffff
2522700:fb00::/242700:fbff:ffff:ffff:ffff:ffff:ffff:ffff
2532700:fc00::/242700:fcff:ffff:ffff:ffff:ffff:ffff:ffff
2542700:fd00::/242700:fdff:ffff:ffff:ffff:ffff:ffff:ffff
2552700:fe00::/242700:feff:ffff:ffff:ffff:ffff:ffff:ffff
2562700:ff00::/242700: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.