Speed and call quality testMy IP addressIP subnet calculatorDNS reportWhoIs lookupRemote support

Internet and network

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.

Computers and devices

Update checkIs this computer, phone and browser up to date? With links to update.Camera and mic testCheck your webcam and microphone before a call.Test print pagePrint an A4 page to check a printer: edges, text, line art and colours.

Make and print

Clean textStrip hidden characters, smart quotes and odd spaces from pasted text.QR code makerMake a QR code for a link, contact or message. Nothing leaves your browser.Wi-Fi QR posterPrint an A4 poster that lets guests join your Wi-Fi by scanning.

Surftec support

Remote supportLet a Surftec engineer connect to your computer to help you.All workingA full-screen confirmation that everything is up and running.

Surftec

Surftec websiteServices, news and how to contact Surftec
Cloud Tools
Guest
GuestNot signed in

Surftec customers will be recognised automatically when they use these tools from their office network.

Customer sign-in is coming soon.

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/12
Addresses2^116
/64 networks2^52
Network
2260::/12
First address
2260::
Last address
226f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
Addresses
83,076,749,736,557,242,056,487,941,267,521,536 (2^116)
/64 networks (LANs)
4,503,599,627,370,496 (2^52)
Full form
2260:0000:0000:0000:0000:0000:0000:0000
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zone
6.2.2.ip6.arpa
Split into smaller subnets/28
/13 (2)/14 (4)/15 (8)/16 (16)/20 (256)/24 (4,096)/28 (65,536)

2260::/12 makes 65,536 subnets of /28; the first 256 are listed.

Subnets
#SubnetLast address
12260::/282260:f:ffff:ffff:ffff:ffff:ffff:ffff
22260:10::/282260:1f:ffff:ffff:ffff:ffff:ffff:ffff
32260:20::/282260:2f:ffff:ffff:ffff:ffff:ffff:ffff
42260:30::/282260:3f:ffff:ffff:ffff:ffff:ffff:ffff
52260:40::/282260:4f:ffff:ffff:ffff:ffff:ffff:ffff
62260:50::/282260:5f:ffff:ffff:ffff:ffff:ffff:ffff
72260:60::/282260:6f:ffff:ffff:ffff:ffff:ffff:ffff
82260:70::/282260:7f:ffff:ffff:ffff:ffff:ffff:ffff
92260:80::/282260:8f:ffff:ffff:ffff:ffff:ffff:ffff
102260:90::/282260:9f:ffff:ffff:ffff:ffff:ffff:ffff
112260:a0::/282260:af:ffff:ffff:ffff:ffff:ffff:ffff
122260:b0::/282260:bf:ffff:ffff:ffff:ffff:ffff:ffff
132260:c0::/282260:cf:ffff:ffff:ffff:ffff:ffff:ffff
142260:d0::/282260:df:ffff:ffff:ffff:ffff:ffff:ffff
152260:e0::/282260:ef:ffff:ffff:ffff:ffff:ffff:ffff
162260:f0::/282260:ff:ffff:ffff:ffff:ffff:ffff:ffff
172260:100::/282260:10f:ffff:ffff:ffff:ffff:ffff:ffff
182260:110::/282260:11f:ffff:ffff:ffff:ffff:ffff:ffff
192260:120::/282260:12f:ffff:ffff:ffff:ffff:ffff:ffff
202260:130::/282260:13f:ffff:ffff:ffff:ffff:ffff:ffff
212260:140::/282260:14f:ffff:ffff:ffff:ffff:ffff:ffff
222260:150::/282260:15f:ffff:ffff:ffff:ffff:ffff:ffff
232260:160::/282260:16f:ffff:ffff:ffff:ffff:ffff:ffff
242260:170::/282260:17f:ffff:ffff:ffff:ffff:ffff:ffff
252260:180::/282260:18f:ffff:ffff:ffff:ffff:ffff:ffff
262260:190::/282260:19f:ffff:ffff:ffff:ffff:ffff:ffff
272260:1a0::/282260:1af:ffff:ffff:ffff:ffff:ffff:ffff
282260:1b0::/282260:1bf:ffff:ffff:ffff:ffff:ffff:ffff
292260:1c0::/282260:1cf:ffff:ffff:ffff:ffff:ffff:ffff
302260:1d0::/282260:1df:ffff:ffff:ffff:ffff:ffff:ffff
312260:1e0::/282260:1ef:ffff:ffff:ffff:ffff:ffff:ffff
322260:1f0::/282260:1ff:ffff:ffff:ffff:ffff:ffff:ffff
332260:200::/282260:20f:ffff:ffff:ffff:ffff:ffff:ffff
342260:210::/282260:21f:ffff:ffff:ffff:ffff:ffff:ffff
352260:220::/282260:22f:ffff:ffff:ffff:ffff:ffff:ffff
362260:230::/282260:23f:ffff:ffff:ffff:ffff:ffff:ffff
372260:240::/282260:24f:ffff:ffff:ffff:ffff:ffff:ffff
382260:250::/282260:25f:ffff:ffff:ffff:ffff:ffff:ffff
392260:260::/282260:26f:ffff:ffff:ffff:ffff:ffff:ffff
402260:270::/282260:27f:ffff:ffff:ffff:ffff:ffff:ffff
412260:280::/282260:28f:ffff:ffff:ffff:ffff:ffff:ffff
422260:290::/282260:29f:ffff:ffff:ffff:ffff:ffff:ffff
432260:2a0::/282260:2af:ffff:ffff:ffff:ffff:ffff:ffff
442260:2b0::/282260:2bf:ffff:ffff:ffff:ffff:ffff:ffff
452260:2c0::/282260:2cf:ffff:ffff:ffff:ffff:ffff:ffff
462260:2d0::/282260:2df:ffff:ffff:ffff:ffff:ffff:ffff
472260:2e0::/282260:2ef:ffff:ffff:ffff:ffff:ffff:ffff
482260:2f0::/282260:2ff:ffff:ffff:ffff:ffff:ffff:ffff
492260:300::/282260:30f:ffff:ffff:ffff:ffff:ffff:ffff
502260:310::/282260:31f:ffff:ffff:ffff:ffff:ffff:ffff
512260:320::/282260:32f:ffff:ffff:ffff:ffff:ffff:ffff
522260:330::/282260:33f:ffff:ffff:ffff:ffff:ffff:ffff
532260:340::/282260:34f:ffff:ffff:ffff:ffff:ffff:ffff
542260:350::/282260:35f:ffff:ffff:ffff:ffff:ffff:ffff
552260:360::/282260:36f:ffff:ffff:ffff:ffff:ffff:ffff
562260:370::/282260:37f:ffff:ffff:ffff:ffff:ffff:ffff
572260:380::/282260:38f:ffff:ffff:ffff:ffff:ffff:ffff
582260:390::/282260:39f:ffff:ffff:ffff:ffff:ffff:ffff
592260:3a0::/282260:3af:ffff:ffff:ffff:ffff:ffff:ffff
602260:3b0::/282260:3bf:ffff:ffff:ffff:ffff:ffff:ffff
612260:3c0::/282260:3cf:ffff:ffff:ffff:ffff:ffff:ffff
622260:3d0::/282260:3df:ffff:ffff:ffff:ffff:ffff:ffff
632260:3e0::/282260:3ef:ffff:ffff:ffff:ffff:ffff:ffff
642260:3f0::/282260:3ff:ffff:ffff:ffff:ffff:ffff:ffff
652260:400::/282260:40f:ffff:ffff:ffff:ffff:ffff:ffff
662260:410::/282260:41f:ffff:ffff:ffff:ffff:ffff:ffff
672260:420::/282260:42f:ffff:ffff:ffff:ffff:ffff:ffff
682260:430::/282260:43f:ffff:ffff:ffff:ffff:ffff:ffff
692260:440::/282260:44f:ffff:ffff:ffff:ffff:ffff:ffff
702260:450::/282260:45f:ffff:ffff:ffff:ffff:ffff:ffff
712260:460::/282260:46f:ffff:ffff:ffff:ffff:ffff:ffff
722260:470::/282260:47f:ffff:ffff:ffff:ffff:ffff:ffff
732260:480::/282260:48f:ffff:ffff:ffff:ffff:ffff:ffff
742260:490::/282260:49f:ffff:ffff:ffff:ffff:ffff:ffff
752260:4a0::/282260:4af:ffff:ffff:ffff:ffff:ffff:ffff
762260:4b0::/282260:4bf:ffff:ffff:ffff:ffff:ffff:ffff
772260:4c0::/282260:4cf:ffff:ffff:ffff:ffff:ffff:ffff
782260:4d0::/282260:4df:ffff:ffff:ffff:ffff:ffff:ffff
792260:4e0::/282260:4ef:ffff:ffff:ffff:ffff:ffff:ffff
802260:4f0::/282260:4ff:ffff:ffff:ffff:ffff:ffff:ffff
812260:500::/282260:50f:ffff:ffff:ffff:ffff:ffff:ffff
822260:510::/282260:51f:ffff:ffff:ffff:ffff:ffff:ffff
832260:520::/282260:52f:ffff:ffff:ffff:ffff:ffff:ffff
842260:530::/282260:53f:ffff:ffff:ffff:ffff:ffff:ffff
852260:540::/282260:54f:ffff:ffff:ffff:ffff:ffff:ffff
862260:550::/282260:55f:ffff:ffff:ffff:ffff:ffff:ffff
872260:560::/282260:56f:ffff:ffff:ffff:ffff:ffff:ffff
882260:570::/282260:57f:ffff:ffff:ffff:ffff:ffff:ffff
892260:580::/282260:58f:ffff:ffff:ffff:ffff:ffff:ffff
902260:590::/282260:59f:ffff:ffff:ffff:ffff:ffff:ffff
912260:5a0::/282260:5af:ffff:ffff:ffff:ffff:ffff:ffff
922260:5b0::/282260:5bf:ffff:ffff:ffff:ffff:ffff:ffff
932260:5c0::/282260:5cf:ffff:ffff:ffff:ffff:ffff:ffff
942260:5d0::/282260:5df:ffff:ffff:ffff:ffff:ffff:ffff
952260:5e0::/282260:5ef:ffff:ffff:ffff:ffff:ffff:ffff
962260:5f0::/282260:5ff:ffff:ffff:ffff:ffff:ffff:ffff
972260:600::/282260:60f:ffff:ffff:ffff:ffff:ffff:ffff
982260:610::/282260:61f:ffff:ffff:ffff:ffff:ffff:ffff
992260:620::/282260:62f:ffff:ffff:ffff:ffff:ffff:ffff
1002260:630::/282260:63f:ffff:ffff:ffff:ffff:ffff:ffff
1012260:640::/282260:64f:ffff:ffff:ffff:ffff:ffff:ffff
1022260:650::/282260:65f:ffff:ffff:ffff:ffff:ffff:ffff
1032260:660::/282260:66f:ffff:ffff:ffff:ffff:ffff:ffff
1042260:670::/282260:67f:ffff:ffff:ffff:ffff:ffff:ffff
1052260:680::/282260:68f:ffff:ffff:ffff:ffff:ffff:ffff
1062260:690::/282260:69f:ffff:ffff:ffff:ffff:ffff:ffff
1072260:6a0::/282260:6af:ffff:ffff:ffff:ffff:ffff:ffff
1082260:6b0::/282260:6bf:ffff:ffff:ffff:ffff:ffff:ffff
1092260:6c0::/282260:6cf:ffff:ffff:ffff:ffff:ffff:ffff
1102260:6d0::/282260:6df:ffff:ffff:ffff:ffff:ffff:ffff
1112260:6e0::/282260:6ef:ffff:ffff:ffff:ffff:ffff:ffff
1122260:6f0::/282260:6ff:ffff:ffff:ffff:ffff:ffff:ffff
1132260:700::/282260:70f:ffff:ffff:ffff:ffff:ffff:ffff
1142260:710::/282260:71f:ffff:ffff:ffff:ffff:ffff:ffff
1152260:720::/282260:72f:ffff:ffff:ffff:ffff:ffff:ffff
1162260:730::/282260:73f:ffff:ffff:ffff:ffff:ffff:ffff
1172260:740::/282260:74f:ffff:ffff:ffff:ffff:ffff:ffff
1182260:750::/282260:75f:ffff:ffff:ffff:ffff:ffff:ffff
1192260:760::/282260:76f:ffff:ffff:ffff:ffff:ffff:ffff
1202260:770::/282260:77f:ffff:ffff:ffff:ffff:ffff:ffff
1212260:780::/282260:78f:ffff:ffff:ffff:ffff:ffff:ffff
1222260:790::/282260:79f:ffff:ffff:ffff:ffff:ffff:ffff
1232260:7a0::/282260:7af:ffff:ffff:ffff:ffff:ffff:ffff
1242260:7b0::/282260:7bf:ffff:ffff:ffff:ffff:ffff:ffff
1252260:7c0::/282260:7cf:ffff:ffff:ffff:ffff:ffff:ffff
1262260:7d0::/282260:7df:ffff:ffff:ffff:ffff:ffff:ffff
1272260:7e0::/282260:7ef:ffff:ffff:ffff:ffff:ffff:ffff
1282260:7f0::/282260:7ff:ffff:ffff:ffff:ffff:ffff:ffff
1292260:800::/282260:80f:ffff:ffff:ffff:ffff:ffff:ffff
1302260:810::/282260:81f:ffff:ffff:ffff:ffff:ffff:ffff
1312260:820::/282260:82f:ffff:ffff:ffff:ffff:ffff:ffff
1322260:830::/282260:83f:ffff:ffff:ffff:ffff:ffff:ffff
1332260:840::/282260:84f:ffff:ffff:ffff:ffff:ffff:ffff
1342260:850::/282260:85f:ffff:ffff:ffff:ffff:ffff:ffff
1352260:860::/282260:86f:ffff:ffff:ffff:ffff:ffff:ffff
1362260:870::/282260:87f:ffff:ffff:ffff:ffff:ffff:ffff
1372260:880::/282260:88f:ffff:ffff:ffff:ffff:ffff:ffff
1382260:890::/282260:89f:ffff:ffff:ffff:ffff:ffff:ffff
1392260:8a0::/282260:8af:ffff:ffff:ffff:ffff:ffff:ffff
1402260:8b0::/282260:8bf:ffff:ffff:ffff:ffff:ffff:ffff
1412260:8c0::/282260:8cf:ffff:ffff:ffff:ffff:ffff:ffff
1422260:8d0::/282260:8df:ffff:ffff:ffff:ffff:ffff:ffff
1432260:8e0::/282260:8ef:ffff:ffff:ffff:ffff:ffff:ffff
1442260:8f0::/282260:8ff:ffff:ffff:ffff:ffff:ffff:ffff
1452260:900::/282260:90f:ffff:ffff:ffff:ffff:ffff:ffff
1462260:910::/282260:91f:ffff:ffff:ffff:ffff:ffff:ffff
1472260:920::/282260:92f:ffff:ffff:ffff:ffff:ffff:ffff
1482260:930::/282260:93f:ffff:ffff:ffff:ffff:ffff:ffff
1492260:940::/282260:94f:ffff:ffff:ffff:ffff:ffff:ffff
1502260:950::/282260:95f:ffff:ffff:ffff:ffff:ffff:ffff
1512260:960::/282260:96f:ffff:ffff:ffff:ffff:ffff:ffff
1522260:970::/282260:97f:ffff:ffff:ffff:ffff:ffff:ffff
1532260:980::/282260:98f:ffff:ffff:ffff:ffff:ffff:ffff
1542260:990::/282260:99f:ffff:ffff:ffff:ffff:ffff:ffff
1552260:9a0::/282260:9af:ffff:ffff:ffff:ffff:ffff:ffff
1562260:9b0::/282260:9bf:ffff:ffff:ffff:ffff:ffff:ffff
1572260:9c0::/282260:9cf:ffff:ffff:ffff:ffff:ffff:ffff
1582260:9d0::/282260:9df:ffff:ffff:ffff:ffff:ffff:ffff
1592260:9e0::/282260:9ef:ffff:ffff:ffff:ffff:ffff:ffff
1602260:9f0::/282260:9ff:ffff:ffff:ffff:ffff:ffff:ffff
1612260:a00::/282260:a0f:ffff:ffff:ffff:ffff:ffff:ffff
1622260:a10::/282260:a1f:ffff:ffff:ffff:ffff:ffff:ffff
1632260:a20::/282260:a2f:ffff:ffff:ffff:ffff:ffff:ffff
1642260:a30::/282260:a3f:ffff:ffff:ffff:ffff:ffff:ffff
1652260:a40::/282260:a4f:ffff:ffff:ffff:ffff:ffff:ffff
1662260:a50::/282260:a5f:ffff:ffff:ffff:ffff:ffff:ffff
1672260:a60::/282260:a6f:ffff:ffff:ffff:ffff:ffff:ffff
1682260:a70::/282260:a7f:ffff:ffff:ffff:ffff:ffff:ffff
1692260:a80::/282260:a8f:ffff:ffff:ffff:ffff:ffff:ffff
1702260:a90::/282260:a9f:ffff:ffff:ffff:ffff:ffff:ffff
1712260:aa0::/282260:aaf:ffff:ffff:ffff:ffff:ffff:ffff
1722260:ab0::/282260:abf:ffff:ffff:ffff:ffff:ffff:ffff
1732260:ac0::/282260:acf:ffff:ffff:ffff:ffff:ffff:ffff
1742260:ad0::/282260:adf:ffff:ffff:ffff:ffff:ffff:ffff
1752260:ae0::/282260:aef:ffff:ffff:ffff:ffff:ffff:ffff
1762260:af0::/282260:aff:ffff:ffff:ffff:ffff:ffff:ffff
1772260:b00::/282260:b0f:ffff:ffff:ffff:ffff:ffff:ffff
1782260:b10::/282260:b1f:ffff:ffff:ffff:ffff:ffff:ffff
1792260:b20::/282260:b2f:ffff:ffff:ffff:ffff:ffff:ffff
1802260:b30::/282260:b3f:ffff:ffff:ffff:ffff:ffff:ffff
1812260:b40::/282260:b4f:ffff:ffff:ffff:ffff:ffff:ffff
1822260:b50::/282260:b5f:ffff:ffff:ffff:ffff:ffff:ffff
1832260:b60::/282260:b6f:ffff:ffff:ffff:ffff:ffff:ffff
1842260:b70::/282260:b7f:ffff:ffff:ffff:ffff:ffff:ffff
1852260:b80::/282260:b8f:ffff:ffff:ffff:ffff:ffff:ffff
1862260:b90::/282260:b9f:ffff:ffff:ffff:ffff:ffff:ffff
1872260:ba0::/282260:baf:ffff:ffff:ffff:ffff:ffff:ffff
1882260:bb0::/282260:bbf:ffff:ffff:ffff:ffff:ffff:ffff
1892260:bc0::/282260:bcf:ffff:ffff:ffff:ffff:ffff:ffff
1902260:bd0::/282260:bdf:ffff:ffff:ffff:ffff:ffff:ffff
1912260:be0::/282260:bef:ffff:ffff:ffff:ffff:ffff:ffff
1922260:bf0::/282260:bff:ffff:ffff:ffff:ffff:ffff:ffff
1932260:c00::/282260:c0f:ffff:ffff:ffff:ffff:ffff:ffff
1942260:c10::/282260:c1f:ffff:ffff:ffff:ffff:ffff:ffff
1952260:c20::/282260:c2f:ffff:ffff:ffff:ffff:ffff:ffff
1962260:c30::/282260:c3f:ffff:ffff:ffff:ffff:ffff:ffff
1972260:c40::/282260:c4f:ffff:ffff:ffff:ffff:ffff:ffff
1982260:c50::/282260:c5f:ffff:ffff:ffff:ffff:ffff:ffff
1992260:c60::/282260:c6f:ffff:ffff:ffff:ffff:ffff:ffff
2002260:c70::/282260:c7f:ffff:ffff:ffff:ffff:ffff:ffff
2012260:c80::/282260:c8f:ffff:ffff:ffff:ffff:ffff:ffff
2022260:c90::/282260:c9f:ffff:ffff:ffff:ffff:ffff:ffff
2032260:ca0::/282260:caf:ffff:ffff:ffff:ffff:ffff:ffff
2042260:cb0::/282260:cbf:ffff:ffff:ffff:ffff:ffff:ffff
2052260:cc0::/282260:ccf:ffff:ffff:ffff:ffff:ffff:ffff
2062260:cd0::/282260:cdf:ffff:ffff:ffff:ffff:ffff:ffff
2072260:ce0::/282260:cef:ffff:ffff:ffff:ffff:ffff:ffff
2082260:cf0::/282260:cff:ffff:ffff:ffff:ffff:ffff:ffff
2092260:d00::/282260:d0f:ffff:ffff:ffff:ffff:ffff:ffff
2102260:d10::/282260:d1f:ffff:ffff:ffff:ffff:ffff:ffff
2112260:d20::/282260:d2f:ffff:ffff:ffff:ffff:ffff:ffff
2122260:d30::/282260:d3f:ffff:ffff:ffff:ffff:ffff:ffff
2132260:d40::/282260:d4f:ffff:ffff:ffff:ffff:ffff:ffff
2142260:d50::/282260:d5f:ffff:ffff:ffff:ffff:ffff:ffff
2152260:d60::/282260:d6f:ffff:ffff:ffff:ffff:ffff:ffff
2162260:d70::/282260:d7f:ffff:ffff:ffff:ffff:ffff:ffff
2172260:d80::/282260:d8f:ffff:ffff:ffff:ffff:ffff:ffff
2182260:d90::/282260:d9f:ffff:ffff:ffff:ffff:ffff:ffff
2192260:da0::/282260:daf:ffff:ffff:ffff:ffff:ffff:ffff
2202260:db0::/282260:dbf:ffff:ffff:ffff:ffff:ffff:ffff
2212260:dc0::/282260:dcf:ffff:ffff:ffff:ffff:ffff:ffff
2222260:dd0::/282260:ddf:ffff:ffff:ffff:ffff:ffff:ffff
2232260:de0::/282260:def:ffff:ffff:ffff:ffff:ffff:ffff
2242260:df0::/282260:dff:ffff:ffff:ffff:ffff:ffff:ffff
2252260:e00::/282260:e0f:ffff:ffff:ffff:ffff:ffff:ffff
2262260:e10::/282260:e1f:ffff:ffff:ffff:ffff:ffff:ffff
2272260:e20::/282260:e2f:ffff:ffff:ffff:ffff:ffff:ffff
2282260:e30::/282260:e3f:ffff:ffff:ffff:ffff:ffff:ffff
2292260:e40::/282260:e4f:ffff:ffff:ffff:ffff:ffff:ffff
2302260:e50::/282260:e5f:ffff:ffff:ffff:ffff:ffff:ffff
2312260:e60::/282260:e6f:ffff:ffff:ffff:ffff:ffff:ffff
2322260:e70::/282260:e7f:ffff:ffff:ffff:ffff:ffff:ffff
2332260:e80::/282260:e8f:ffff:ffff:ffff:ffff:ffff:ffff
2342260:e90::/282260:e9f:ffff:ffff:ffff:ffff:ffff:ffff
2352260:ea0::/282260:eaf:ffff:ffff:ffff:ffff:ffff:ffff
2362260:eb0::/282260:ebf:ffff:ffff:ffff:ffff:ffff:ffff
2372260:ec0::/282260:ecf:ffff:ffff:ffff:ffff:ffff:ffff
2382260:ed0::/282260:edf:ffff:ffff:ffff:ffff:ffff:ffff
2392260:ee0::/282260:eef:ffff:ffff:ffff:ffff:ffff:ffff
2402260:ef0::/282260:eff:ffff:ffff:ffff:ffff:ffff:ffff
2412260:f00::/282260:f0f:ffff:ffff:ffff:ffff:ffff:ffff
2422260:f10::/282260:f1f:ffff:ffff:ffff:ffff:ffff:ffff
2432260:f20::/282260:f2f:ffff:ffff:ffff:ffff:ffff:ffff
2442260:f30::/282260:f3f:ffff:ffff:ffff:ffff:ffff:ffff
2452260:f40::/282260:f4f:ffff:ffff:ffff:ffff:ffff:ffff
2462260:f50::/282260:f5f:ffff:ffff:ffff:ffff:ffff:ffff
2472260:f60::/282260:f6f:ffff:ffff:ffff:ffff:ffff:ffff
2482260:f70::/282260:f7f:ffff:ffff:ffff:ffff:ffff:ffff
2492260:f80::/282260:f8f:ffff:ffff:ffff:ffff:ffff:ffff
2502260:f90::/282260:f9f:ffff:ffff:ffff:ffff:ffff:ffff
2512260:fa0::/282260:faf:ffff:ffff:ffff:ffff:ffff:ffff
2522260:fb0::/282260:fbf:ffff:ffff:ffff:ffff:ffff:ffff
2532260:fc0::/282260:fcf:ffff:ffff:ffff:ffff:ffff:ffff
2542260:fd0::/282260:fdf:ffff:ffff:ffff:ffff:ffff:ffff
2552260:fe0::/282260:fef:ffff:ffff:ffff:ffff:ffff:ffff
2562260:ff0::/282260:fff: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.