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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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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.

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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/7
Addresses2^121
/64 networks2^57
Network
3200::/7
First address
3200::
Last address
33ff:ffff:ffff:ffff:ffff:ffff:ffff:ffff
Addresses
2,658,455,991,569,831,745,807,614,120,560,689,152 (2^121)
/64 networks (LANs)
144,115,188,075,855,872 (2^57)
Full form
3200:0000:0000:0000:0000:0000:0000:0000
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zones
2.3.ip6.arpa
3.3.ip6.arpa
/7 is not on a 4-bit boundary, so it takes 2 /8 zones.
Split into smaller subnets/16
/8 (2)/9 (4)/10 (8)/11 (16)/12 (32)/16 (512)/20 (8,192)

3200::/7 makes 512 subnets of /16; the first 256 are listed.

Subnets
#SubnetLast address
13200::/163200:ffff:ffff:ffff:ffff:ffff:ffff:ffff
23201::/163201:ffff:ffff:ffff:ffff:ffff:ffff:ffff
33202::/163202:ffff:ffff:ffff:ffff:ffff:ffff:ffff
43203::/163203:ffff:ffff:ffff:ffff:ffff:ffff:ffff
53204::/163204:ffff:ffff:ffff:ffff:ffff:ffff:ffff
63205::/163205:ffff:ffff:ffff:ffff:ffff:ffff:ffff
73206::/163206:ffff:ffff:ffff:ffff:ffff:ffff:ffff
83207::/163207:ffff:ffff:ffff:ffff:ffff:ffff:ffff
93208::/163208:ffff:ffff:ffff:ffff:ffff:ffff:ffff
103209::/163209:ffff:ffff:ffff:ffff:ffff:ffff:ffff
11320a::/16320a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
12320b::/16320b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
13320c::/16320c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
14320d::/16320d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
15320e::/16320e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
16320f::/16320f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
173210::/163210:ffff:ffff:ffff:ffff:ffff:ffff:ffff
183211::/163211:ffff:ffff:ffff:ffff:ffff:ffff:ffff
193212::/163212:ffff:ffff:ffff:ffff:ffff:ffff:ffff
203213::/163213:ffff:ffff:ffff:ffff:ffff:ffff:ffff
213214::/163214:ffff:ffff:ffff:ffff:ffff:ffff:ffff
223215::/163215:ffff:ffff:ffff:ffff:ffff:ffff:ffff
233216::/163216:ffff:ffff:ffff:ffff:ffff:ffff:ffff
243217::/163217:ffff:ffff:ffff:ffff:ffff:ffff:ffff
253218::/163218:ffff:ffff:ffff:ffff:ffff:ffff:ffff
263219::/163219:ffff:ffff:ffff:ffff:ffff:ffff:ffff
27321a::/16321a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
28321b::/16321b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
29321c::/16321c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
30321d::/16321d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
31321e::/16321e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
32321f::/16321f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
333220::/163220:ffff:ffff:ffff:ffff:ffff:ffff:ffff
343221::/163221:ffff:ffff:ffff:ffff:ffff:ffff:ffff
353222::/163222:ffff:ffff:ffff:ffff:ffff:ffff:ffff
363223::/163223:ffff:ffff:ffff:ffff:ffff:ffff:ffff
373224::/163224:ffff:ffff:ffff:ffff:ffff:ffff:ffff
383225::/163225:ffff:ffff:ffff:ffff:ffff:ffff:ffff
393226::/163226:ffff:ffff:ffff:ffff:ffff:ffff:ffff
403227::/163227:ffff:ffff:ffff:ffff:ffff:ffff:ffff
413228::/163228:ffff:ffff:ffff:ffff:ffff:ffff:ffff
423229::/163229:ffff:ffff:ffff:ffff:ffff:ffff:ffff
43322a::/16322a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
44322b::/16322b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
45322c::/16322c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
46322d::/16322d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
47322e::/16322e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
48322f::/16322f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
493230::/163230:ffff:ffff:ffff:ffff:ffff:ffff:ffff
503231::/163231:ffff:ffff:ffff:ffff:ffff:ffff:ffff
513232::/163232:ffff:ffff:ffff:ffff:ffff:ffff:ffff
523233::/163233:ffff:ffff:ffff:ffff:ffff:ffff:ffff
533234::/163234:ffff:ffff:ffff:ffff:ffff:ffff:ffff
543235::/163235:ffff:ffff:ffff:ffff:ffff:ffff:ffff
553236::/163236:ffff:ffff:ffff:ffff:ffff:ffff:ffff
563237::/163237:ffff:ffff:ffff:ffff:ffff:ffff:ffff
573238::/163238:ffff:ffff:ffff:ffff:ffff:ffff:ffff
583239::/163239:ffff:ffff:ffff:ffff:ffff:ffff:ffff
59323a::/16323a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
60323b::/16323b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
61323c::/16323c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
62323d::/16323d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
63323e::/16323e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
64323f::/16323f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
653240::/163240:ffff:ffff:ffff:ffff:ffff:ffff:ffff
663241::/163241:ffff:ffff:ffff:ffff:ffff:ffff:ffff
673242::/163242:ffff:ffff:ffff:ffff:ffff:ffff:ffff
683243::/163243:ffff:ffff:ffff:ffff:ffff:ffff:ffff
693244::/163244:ffff:ffff:ffff:ffff:ffff:ffff:ffff
703245::/163245:ffff:ffff:ffff:ffff:ffff:ffff:ffff
713246::/163246:ffff:ffff:ffff:ffff:ffff:ffff:ffff
723247::/163247:ffff:ffff:ffff:ffff:ffff:ffff:ffff
733248::/163248:ffff:ffff:ffff:ffff:ffff:ffff:ffff
743249::/163249:ffff:ffff:ffff:ffff:ffff:ffff:ffff
75324a::/16324a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
76324b::/16324b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
77324c::/16324c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
78324d::/16324d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
79324e::/16324e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
80324f::/16324f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
813250::/163250:ffff:ffff:ffff:ffff:ffff:ffff:ffff
823251::/163251:ffff:ffff:ffff:ffff:ffff:ffff:ffff
833252::/163252:ffff:ffff:ffff:ffff:ffff:ffff:ffff
843253::/163253:ffff:ffff:ffff:ffff:ffff:ffff:ffff
853254::/163254:ffff:ffff:ffff:ffff:ffff:ffff:ffff
863255::/163255:ffff:ffff:ffff:ffff:ffff:ffff:ffff
873256::/163256:ffff:ffff:ffff:ffff:ffff:ffff:ffff
883257::/163257:ffff:ffff:ffff:ffff:ffff:ffff:ffff
893258::/163258:ffff:ffff:ffff:ffff:ffff:ffff:ffff
903259::/163259:ffff:ffff:ffff:ffff:ffff:ffff:ffff
91325a::/16325a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
92325b::/16325b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
93325c::/16325c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
94325d::/16325d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
95325e::/16325e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
96325f::/16325f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
973260::/163260:ffff:ffff:ffff:ffff:ffff:ffff:ffff
983261::/163261:ffff:ffff:ffff:ffff:ffff:ffff:ffff
993262::/163262:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1003263::/163263:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1013264::/163264:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1023265::/163265:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1033266::/163266:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1043267::/163267:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1053268::/163268:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1063269::/163269:ffff:ffff:ffff:ffff:ffff:ffff:ffff
107326a::/16326a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
108326b::/16326b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
109326c::/16326c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
110326d::/16326d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
111326e::/16326e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
112326f::/16326f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1133270::/163270:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1143271::/163271:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1153272::/163272:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1163273::/163273:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1173274::/163274:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1183275::/163275:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1193276::/163276:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1203277::/163277:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1213278::/163278:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1223279::/163279:ffff:ffff:ffff:ffff:ffff:ffff:ffff
123327a::/16327a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
124327b::/16327b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
125327c::/16327c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
126327d::/16327d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
127327e::/16327e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
128327f::/16327f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1293280::/163280:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1303281::/163281:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1313282::/163282:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1323283::/163283:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1333284::/163284:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1343285::/163285:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1353286::/163286:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1363287::/163287:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1373288::/163288:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1383289::/163289:ffff:ffff:ffff:ffff:ffff:ffff:ffff
139328a::/16328a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
140328b::/16328b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
141328c::/16328c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
142328d::/16328d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
143328e::/16328e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
144328f::/16328f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1453290::/163290:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1463291::/163291:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1473292::/163292:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1483293::/163293:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1493294::/163294:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1503295::/163295:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1513296::/163296:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1523297::/163297:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1533298::/163298:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1543299::/163299:ffff:ffff:ffff:ffff:ffff:ffff:ffff
155329a::/16329a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
156329b::/16329b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
157329c::/16329c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
158329d::/16329d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
159329e::/16329e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
160329f::/16329f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
16132a0::/1632a0:ffff:ffff:ffff:ffff:ffff:ffff:ffff
16232a1::/1632a1:ffff:ffff:ffff:ffff:ffff:ffff:ffff
16332a2::/1632a2:ffff:ffff:ffff:ffff:ffff:ffff:ffff
16432a3::/1632a3:ffff:ffff:ffff:ffff:ffff:ffff:ffff
16532a4::/1632a4:ffff:ffff:ffff:ffff:ffff:ffff:ffff
16632a5::/1632a5:ffff:ffff:ffff:ffff:ffff:ffff:ffff
16732a6::/1632a6:ffff:ffff:ffff:ffff:ffff:ffff:ffff
16832a7::/1632a7:ffff:ffff:ffff:ffff:ffff:ffff:ffff
16932a8::/1632a8:ffff:ffff:ffff:ffff:ffff:ffff:ffff
17032a9::/1632a9:ffff:ffff:ffff:ffff:ffff:ffff:ffff
17132aa::/1632aa:ffff:ffff:ffff:ffff:ffff:ffff:ffff
17232ab::/1632ab:ffff:ffff:ffff:ffff:ffff:ffff:ffff
17332ac::/1632ac:ffff:ffff:ffff:ffff:ffff:ffff:ffff
17432ad::/1632ad:ffff:ffff:ffff:ffff:ffff:ffff:ffff
17532ae::/1632ae:ffff:ffff:ffff:ffff:ffff:ffff:ffff
17632af::/1632af:ffff:ffff:ffff:ffff:ffff:ffff:ffff
17732b0::/1632b0:ffff:ffff:ffff:ffff:ffff:ffff:ffff
17832b1::/1632b1:ffff:ffff:ffff:ffff:ffff:ffff:ffff
17932b2::/1632b2:ffff:ffff:ffff:ffff:ffff:ffff:ffff
18032b3::/1632b3:ffff:ffff:ffff:ffff:ffff:ffff:ffff
18132b4::/1632b4:ffff:ffff:ffff:ffff:ffff:ffff:ffff
18232b5::/1632b5:ffff:ffff:ffff:ffff:ffff:ffff:ffff
18332b6::/1632b6:ffff:ffff:ffff:ffff:ffff:ffff:ffff
18432b7::/1632b7:ffff:ffff:ffff:ffff:ffff:ffff:ffff
18532b8::/1632b8:ffff:ffff:ffff:ffff:ffff:ffff:ffff
18632b9::/1632b9:ffff:ffff:ffff:ffff:ffff:ffff:ffff
18732ba::/1632ba:ffff:ffff:ffff:ffff:ffff:ffff:ffff
18832bb::/1632bb:ffff:ffff:ffff:ffff:ffff:ffff:ffff
18932bc::/1632bc:ffff:ffff:ffff:ffff:ffff:ffff:ffff
19032bd::/1632bd:ffff:ffff:ffff:ffff:ffff:ffff:ffff
19132be::/1632be:ffff:ffff:ffff:ffff:ffff:ffff:ffff
19232bf::/1632bf:ffff:ffff:ffff:ffff:ffff:ffff:ffff
19332c0::/1632c0:ffff:ffff:ffff:ffff:ffff:ffff:ffff
19432c1::/1632c1:ffff:ffff:ffff:ffff:ffff:ffff:ffff
19532c2::/1632c2:ffff:ffff:ffff:ffff:ffff:ffff:ffff
19632c3::/1632c3:ffff:ffff:ffff:ffff:ffff:ffff:ffff
19732c4::/1632c4:ffff:ffff:ffff:ffff:ffff:ffff:ffff
19832c5::/1632c5:ffff:ffff:ffff:ffff:ffff:ffff:ffff
19932c6::/1632c6:ffff:ffff:ffff:ffff:ffff:ffff:ffff
20032c7::/1632c7:ffff:ffff:ffff:ffff:ffff:ffff:ffff
20132c8::/1632c8:ffff:ffff:ffff:ffff:ffff:ffff:ffff
20232c9::/1632c9:ffff:ffff:ffff:ffff:ffff:ffff:ffff
20332ca::/1632ca:ffff:ffff:ffff:ffff:ffff:ffff:ffff
20432cb::/1632cb:ffff:ffff:ffff:ffff:ffff:ffff:ffff
20532cc::/1632cc:ffff:ffff:ffff:ffff:ffff:ffff:ffff
20632cd::/1632cd:ffff:ffff:ffff:ffff:ffff:ffff:ffff
20732ce::/1632ce:ffff:ffff:ffff:ffff:ffff:ffff:ffff
20832cf::/1632cf:ffff:ffff:ffff:ffff:ffff:ffff:ffff
20932d0::/1632d0:ffff:ffff:ffff:ffff:ffff:ffff:ffff
21032d1::/1632d1:ffff:ffff:ffff:ffff:ffff:ffff:ffff
21132d2::/1632d2:ffff:ffff:ffff:ffff:ffff:ffff:ffff
21232d3::/1632d3:ffff:ffff:ffff:ffff:ffff:ffff:ffff
21332d4::/1632d4:ffff:ffff:ffff:ffff:ffff:ffff:ffff
21432d5::/1632d5:ffff:ffff:ffff:ffff:ffff:ffff:ffff
21532d6::/1632d6:ffff:ffff:ffff:ffff:ffff:ffff:ffff
21632d7::/1632d7:ffff:ffff:ffff:ffff:ffff:ffff:ffff
21732d8::/1632d8:ffff:ffff:ffff:ffff:ffff:ffff:ffff
21832d9::/1632d9:ffff:ffff:ffff:ffff:ffff:ffff:ffff
21932da::/1632da:ffff:ffff:ffff:ffff:ffff:ffff:ffff
22032db::/1632db:ffff:ffff:ffff:ffff:ffff:ffff:ffff
22132dc::/1632dc:ffff:ffff:ffff:ffff:ffff:ffff:ffff
22232dd::/1632dd:ffff:ffff:ffff:ffff:ffff:ffff:ffff
22332de::/1632de:ffff:ffff:ffff:ffff:ffff:ffff:ffff
22432df::/1632df:ffff:ffff:ffff:ffff:ffff:ffff:ffff
22532e0::/1632e0:ffff:ffff:ffff:ffff:ffff:ffff:ffff
22632e1::/1632e1:ffff:ffff:ffff:ffff:ffff:ffff:ffff
22732e2::/1632e2:ffff:ffff:ffff:ffff:ffff:ffff:ffff
22832e3::/1632e3:ffff:ffff:ffff:ffff:ffff:ffff:ffff
22932e4::/1632e4:ffff:ffff:ffff:ffff:ffff:ffff:ffff
23032e5::/1632e5:ffff:ffff:ffff:ffff:ffff:ffff:ffff
23132e6::/1632e6:ffff:ffff:ffff:ffff:ffff:ffff:ffff
23232e7::/1632e7:ffff:ffff:ffff:ffff:ffff:ffff:ffff
23332e8::/1632e8:ffff:ffff:ffff:ffff:ffff:ffff:ffff
23432e9::/1632e9:ffff:ffff:ffff:ffff:ffff:ffff:ffff
23532ea::/1632ea:ffff:ffff:ffff:ffff:ffff:ffff:ffff
23632eb::/1632eb:ffff:ffff:ffff:ffff:ffff:ffff:ffff
23732ec::/1632ec:ffff:ffff:ffff:ffff:ffff:ffff:ffff
23832ed::/1632ed:ffff:ffff:ffff:ffff:ffff:ffff:ffff
23932ee::/1632ee:ffff:ffff:ffff:ffff:ffff:ffff:ffff
24032ef::/1632ef:ffff:ffff:ffff:ffff:ffff:ffff:ffff
24132f0::/1632f0:ffff:ffff:ffff:ffff:ffff:ffff:ffff
24232f1::/1632f1:ffff:ffff:ffff:ffff:ffff:ffff:ffff
24332f2::/1632f2:ffff:ffff:ffff:ffff:ffff:ffff:ffff
24432f3::/1632f3:ffff:ffff:ffff:ffff:ffff:ffff:ffff
24532f4::/1632f4:ffff:ffff:ffff:ffff:ffff:ffff:ffff
24632f5::/1632f5:ffff:ffff:ffff:ffff:ffff:ffff:ffff
24732f6::/1632f6:ffff:ffff:ffff:ffff:ffff:ffff:ffff
24832f7::/1632f7:ffff:ffff:ffff:ffff:ffff:ffff:ffff
24932f8::/1632f8:ffff:ffff:ffff:ffff:ffff:ffff:ffff
25032f9::/1632f9:ffff:ffff:ffff:ffff:ffff:ffff:ffff
25132fa::/1632fa:ffff:ffff:ffff:ffff:ffff:ffff:ffff
25232fb::/1632fb:ffff:ffff:ffff:ffff:ffff:ffff:ffff
25332fc::/1632fc:ffff:ffff:ffff:ffff:ffff:ffff:ffff
25432fd::/1632fd:ffff:ffff:ffff:ffff:ffff:ffff:ffff
25532fe::/1632fe:ffff:ffff:ffff:ffff:ffff:ffff:ffff
25632ff::/1632ff: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.