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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
2200::/7
First address
2200::
Last address
23ff: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
2200:0000:0000:0000:0000:0000:0000:0000
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zones
2.2.ip6.arpa
3.2.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)

2200::/7 makes 512 subnets of /16; the first 256 are listed.

Subnets
#SubnetLast address
12200::/162200:ffff:ffff:ffff:ffff:ffff:ffff:ffff
22201::/162201:ffff:ffff:ffff:ffff:ffff:ffff:ffff
32202::/162202:ffff:ffff:ffff:ffff:ffff:ffff:ffff
42203::/162203:ffff:ffff:ffff:ffff:ffff:ffff:ffff
52204::/162204:ffff:ffff:ffff:ffff:ffff:ffff:ffff
62205::/162205:ffff:ffff:ffff:ffff:ffff:ffff:ffff
72206::/162206:ffff:ffff:ffff:ffff:ffff:ffff:ffff
82207::/162207:ffff:ffff:ffff:ffff:ffff:ffff:ffff
92208::/162208:ffff:ffff:ffff:ffff:ffff:ffff:ffff
102209::/162209:ffff:ffff:ffff:ffff:ffff:ffff:ffff
11220a::/16220a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
12220b::/16220b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
13220c::/16220c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
14220d::/16220d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
15220e::/16220e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
16220f::/16220f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
172210::/162210:ffff:ffff:ffff:ffff:ffff:ffff:ffff
182211::/162211:ffff:ffff:ffff:ffff:ffff:ffff:ffff
192212::/162212:ffff:ffff:ffff:ffff:ffff:ffff:ffff
202213::/162213:ffff:ffff:ffff:ffff:ffff:ffff:ffff
212214::/162214:ffff:ffff:ffff:ffff:ffff:ffff:ffff
222215::/162215:ffff:ffff:ffff:ffff:ffff:ffff:ffff
232216::/162216:ffff:ffff:ffff:ffff:ffff:ffff:ffff
242217::/162217:ffff:ffff:ffff:ffff:ffff:ffff:ffff
252218::/162218:ffff:ffff:ffff:ffff:ffff:ffff:ffff
262219::/162219:ffff:ffff:ffff:ffff:ffff:ffff:ffff
27221a::/16221a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
28221b::/16221b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
29221c::/16221c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
30221d::/16221d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
31221e::/16221e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
32221f::/16221f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
332220::/162220:ffff:ffff:ffff:ffff:ffff:ffff:ffff
342221::/162221:ffff:ffff:ffff:ffff:ffff:ffff:ffff
352222::/162222:ffff:ffff:ffff:ffff:ffff:ffff:ffff
362223::/162223:ffff:ffff:ffff:ffff:ffff:ffff:ffff
372224::/162224:ffff:ffff:ffff:ffff:ffff:ffff:ffff
382225::/162225:ffff:ffff:ffff:ffff:ffff:ffff:ffff
392226::/162226:ffff:ffff:ffff:ffff:ffff:ffff:ffff
402227::/162227:ffff:ffff:ffff:ffff:ffff:ffff:ffff
412228::/162228:ffff:ffff:ffff:ffff:ffff:ffff:ffff
422229::/162229:ffff:ffff:ffff:ffff:ffff:ffff:ffff
43222a::/16222a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
44222b::/16222b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
45222c::/16222c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
46222d::/16222d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
47222e::/16222e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
48222f::/16222f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
492230::/162230:ffff:ffff:ffff:ffff:ffff:ffff:ffff
502231::/162231:ffff:ffff:ffff:ffff:ffff:ffff:ffff
512232::/162232:ffff:ffff:ffff:ffff:ffff:ffff:ffff
522233::/162233:ffff:ffff:ffff:ffff:ffff:ffff:ffff
532234::/162234:ffff:ffff:ffff:ffff:ffff:ffff:ffff
542235::/162235:ffff:ffff:ffff:ffff:ffff:ffff:ffff
552236::/162236:ffff:ffff:ffff:ffff:ffff:ffff:ffff
562237::/162237:ffff:ffff:ffff:ffff:ffff:ffff:ffff
572238::/162238:ffff:ffff:ffff:ffff:ffff:ffff:ffff
582239::/162239:ffff:ffff:ffff:ffff:ffff:ffff:ffff
59223a::/16223a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
60223b::/16223b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
61223c::/16223c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
62223d::/16223d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
63223e::/16223e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
64223f::/16223f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
652240::/162240:ffff:ffff:ffff:ffff:ffff:ffff:ffff
662241::/162241:ffff:ffff:ffff:ffff:ffff:ffff:ffff
672242::/162242:ffff:ffff:ffff:ffff:ffff:ffff:ffff
682243::/162243:ffff:ffff:ffff:ffff:ffff:ffff:ffff
692244::/162244:ffff:ffff:ffff:ffff:ffff:ffff:ffff
702245::/162245:ffff:ffff:ffff:ffff:ffff:ffff:ffff
712246::/162246:ffff:ffff:ffff:ffff:ffff:ffff:ffff
722247::/162247:ffff:ffff:ffff:ffff:ffff:ffff:ffff
732248::/162248:ffff:ffff:ffff:ffff:ffff:ffff:ffff
742249::/162249:ffff:ffff:ffff:ffff:ffff:ffff:ffff
75224a::/16224a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
76224b::/16224b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
77224c::/16224c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
78224d::/16224d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
79224e::/16224e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
80224f::/16224f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
812250::/162250:ffff:ffff:ffff:ffff:ffff:ffff:ffff
822251::/162251:ffff:ffff:ffff:ffff:ffff:ffff:ffff
832252::/162252:ffff:ffff:ffff:ffff:ffff:ffff:ffff
842253::/162253:ffff:ffff:ffff:ffff:ffff:ffff:ffff
852254::/162254:ffff:ffff:ffff:ffff:ffff:ffff:ffff
862255::/162255:ffff:ffff:ffff:ffff:ffff:ffff:ffff
872256::/162256:ffff:ffff:ffff:ffff:ffff:ffff:ffff
882257::/162257:ffff:ffff:ffff:ffff:ffff:ffff:ffff
892258::/162258:ffff:ffff:ffff:ffff:ffff:ffff:ffff
902259::/162259:ffff:ffff:ffff:ffff:ffff:ffff:ffff
91225a::/16225a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
92225b::/16225b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
93225c::/16225c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
94225d::/16225d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
95225e::/16225e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
96225f::/16225f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
972260::/162260:ffff:ffff:ffff:ffff:ffff:ffff:ffff
982261::/162261:ffff:ffff:ffff:ffff:ffff:ffff:ffff
992262::/162262:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1002263::/162263:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1012264::/162264:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1022265::/162265:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1032266::/162266:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1042267::/162267:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1052268::/162268:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1062269::/162269:ffff:ffff:ffff:ffff:ffff:ffff:ffff
107226a::/16226a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
108226b::/16226b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
109226c::/16226c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
110226d::/16226d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
111226e::/16226e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
112226f::/16226f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1132270::/162270:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1142271::/162271:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1152272::/162272:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1162273::/162273:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1172274::/162274:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1182275::/162275:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1192276::/162276:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1202277::/162277:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1212278::/162278:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1222279::/162279:ffff:ffff:ffff:ffff:ffff:ffff:ffff
123227a::/16227a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
124227b::/16227b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
125227c::/16227c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
126227d::/16227d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
127227e::/16227e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
128227f::/16227f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1292280::/162280:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1302281::/162281:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1312282::/162282:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1322283::/162283:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1332284::/162284:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1342285::/162285:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1352286::/162286:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1362287::/162287:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1372288::/162288:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1382289::/162289:ffff:ffff:ffff:ffff:ffff:ffff:ffff
139228a::/16228a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
140228b::/16228b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
141228c::/16228c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
142228d::/16228d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
143228e::/16228e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
144228f::/16228f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1452290::/162290:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1462291::/162291:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1472292::/162292:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1482293::/162293:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1492294::/162294:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1502295::/162295:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1512296::/162296:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1522297::/162297:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1532298::/162298:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1542299::/162299:ffff:ffff:ffff:ffff:ffff:ffff:ffff
155229a::/16229a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
156229b::/16229b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
157229c::/16229c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
158229d::/16229d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
159229e::/16229e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
160229f::/16229f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
16122a0::/1622a0:ffff:ffff:ffff:ffff:ffff:ffff:ffff
16222a1::/1622a1:ffff:ffff:ffff:ffff:ffff:ffff:ffff
16322a2::/1622a2:ffff:ffff:ffff:ffff:ffff:ffff:ffff
16422a3::/1622a3:ffff:ffff:ffff:ffff:ffff:ffff:ffff
16522a4::/1622a4:ffff:ffff:ffff:ffff:ffff:ffff:ffff
16622a5::/1622a5:ffff:ffff:ffff:ffff:ffff:ffff:ffff
16722a6::/1622a6:ffff:ffff:ffff:ffff:ffff:ffff:ffff
16822a7::/1622a7:ffff:ffff:ffff:ffff:ffff:ffff:ffff
16922a8::/1622a8:ffff:ffff:ffff:ffff:ffff:ffff:ffff
17022a9::/1622a9:ffff:ffff:ffff:ffff:ffff:ffff:ffff
17122aa::/1622aa:ffff:ffff:ffff:ffff:ffff:ffff:ffff
17222ab::/1622ab:ffff:ffff:ffff:ffff:ffff:ffff:ffff
17322ac::/1622ac:ffff:ffff:ffff:ffff:ffff:ffff:ffff
17422ad::/1622ad:ffff:ffff:ffff:ffff:ffff:ffff:ffff
17522ae::/1622ae:ffff:ffff:ffff:ffff:ffff:ffff:ffff
17622af::/1622af:ffff:ffff:ffff:ffff:ffff:ffff:ffff
17722b0::/1622b0:ffff:ffff:ffff:ffff:ffff:ffff:ffff
17822b1::/1622b1:ffff:ffff:ffff:ffff:ffff:ffff:ffff
17922b2::/1622b2:ffff:ffff:ffff:ffff:ffff:ffff:ffff
18022b3::/1622b3:ffff:ffff:ffff:ffff:ffff:ffff:ffff
18122b4::/1622b4:ffff:ffff:ffff:ffff:ffff:ffff:ffff
18222b5::/1622b5:ffff:ffff:ffff:ffff:ffff:ffff:ffff
18322b6::/1622b6:ffff:ffff:ffff:ffff:ffff:ffff:ffff
18422b7::/1622b7:ffff:ffff:ffff:ffff:ffff:ffff:ffff
18522b8::/1622b8:ffff:ffff:ffff:ffff:ffff:ffff:ffff
18622b9::/1622b9:ffff:ffff:ffff:ffff:ffff:ffff:ffff
18722ba::/1622ba:ffff:ffff:ffff:ffff:ffff:ffff:ffff
18822bb::/1622bb:ffff:ffff:ffff:ffff:ffff:ffff:ffff
18922bc::/1622bc:ffff:ffff:ffff:ffff:ffff:ffff:ffff
19022bd::/1622bd:ffff:ffff:ffff:ffff:ffff:ffff:ffff
19122be::/1622be:ffff:ffff:ffff:ffff:ffff:ffff:ffff
19222bf::/1622bf:ffff:ffff:ffff:ffff:ffff:ffff:ffff
19322c0::/1622c0:ffff:ffff:ffff:ffff:ffff:ffff:ffff
19422c1::/1622c1:ffff:ffff:ffff:ffff:ffff:ffff:ffff
19522c2::/1622c2:ffff:ffff:ffff:ffff:ffff:ffff:ffff
19622c3::/1622c3:ffff:ffff:ffff:ffff:ffff:ffff:ffff
19722c4::/1622c4:ffff:ffff:ffff:ffff:ffff:ffff:ffff
19822c5::/1622c5:ffff:ffff:ffff:ffff:ffff:ffff:ffff
19922c6::/1622c6:ffff:ffff:ffff:ffff:ffff:ffff:ffff
20022c7::/1622c7:ffff:ffff:ffff:ffff:ffff:ffff:ffff
20122c8::/1622c8:ffff:ffff:ffff:ffff:ffff:ffff:ffff
20222c9::/1622c9:ffff:ffff:ffff:ffff:ffff:ffff:ffff
20322ca::/1622ca:ffff:ffff:ffff:ffff:ffff:ffff:ffff
20422cb::/1622cb:ffff:ffff:ffff:ffff:ffff:ffff:ffff
20522cc::/1622cc:ffff:ffff:ffff:ffff:ffff:ffff:ffff
20622cd::/1622cd:ffff:ffff:ffff:ffff:ffff:ffff:ffff
20722ce::/1622ce:ffff:ffff:ffff:ffff:ffff:ffff:ffff
20822cf::/1622cf:ffff:ffff:ffff:ffff:ffff:ffff:ffff
20922d0::/1622d0:ffff:ffff:ffff:ffff:ffff:ffff:ffff
21022d1::/1622d1:ffff:ffff:ffff:ffff:ffff:ffff:ffff
21122d2::/1622d2:ffff:ffff:ffff:ffff:ffff:ffff:ffff
21222d3::/1622d3:ffff:ffff:ffff:ffff:ffff:ffff:ffff
21322d4::/1622d4:ffff:ffff:ffff:ffff:ffff:ffff:ffff
21422d5::/1622d5:ffff:ffff:ffff:ffff:ffff:ffff:ffff
21522d6::/1622d6:ffff:ffff:ffff:ffff:ffff:ffff:ffff
21622d7::/1622d7:ffff:ffff:ffff:ffff:ffff:ffff:ffff
21722d8::/1622d8:ffff:ffff:ffff:ffff:ffff:ffff:ffff
21822d9::/1622d9:ffff:ffff:ffff:ffff:ffff:ffff:ffff
21922da::/1622da:ffff:ffff:ffff:ffff:ffff:ffff:ffff
22022db::/1622db:ffff:ffff:ffff:ffff:ffff:ffff:ffff
22122dc::/1622dc:ffff:ffff:ffff:ffff:ffff:ffff:ffff
22222dd::/1622dd:ffff:ffff:ffff:ffff:ffff:ffff:ffff
22322de::/1622de:ffff:ffff:ffff:ffff:ffff:ffff:ffff
22422df::/1622df:ffff:ffff:ffff:ffff:ffff:ffff:ffff
22522e0::/1622e0:ffff:ffff:ffff:ffff:ffff:ffff:ffff
22622e1::/1622e1:ffff:ffff:ffff:ffff:ffff:ffff:ffff
22722e2::/1622e2:ffff:ffff:ffff:ffff:ffff:ffff:ffff
22822e3::/1622e3:ffff:ffff:ffff:ffff:ffff:ffff:ffff
22922e4::/1622e4:ffff:ffff:ffff:ffff:ffff:ffff:ffff
23022e5::/1622e5:ffff:ffff:ffff:ffff:ffff:ffff:ffff
23122e6::/1622e6:ffff:ffff:ffff:ffff:ffff:ffff:ffff
23222e7::/1622e7:ffff:ffff:ffff:ffff:ffff:ffff:ffff
23322e8::/1622e8:ffff:ffff:ffff:ffff:ffff:ffff:ffff
23422e9::/1622e9:ffff:ffff:ffff:ffff:ffff:ffff:ffff
23522ea::/1622ea:ffff:ffff:ffff:ffff:ffff:ffff:ffff
23622eb::/1622eb:ffff:ffff:ffff:ffff:ffff:ffff:ffff
23722ec::/1622ec:ffff:ffff:ffff:ffff:ffff:ffff:ffff
23822ed::/1622ed:ffff:ffff:ffff:ffff:ffff:ffff:ffff
23922ee::/1622ee:ffff:ffff:ffff:ffff:ffff:ffff:ffff
24022ef::/1622ef:ffff:ffff:ffff:ffff:ffff:ffff:ffff
24122f0::/1622f0:ffff:ffff:ffff:ffff:ffff:ffff:ffff
24222f1::/1622f1:ffff:ffff:ffff:ffff:ffff:ffff:ffff
24322f2::/1622f2:ffff:ffff:ffff:ffff:ffff:ffff:ffff
24422f3::/1622f3:ffff:ffff:ffff:ffff:ffff:ffff:ffff
24522f4::/1622f4:ffff:ffff:ffff:ffff:ffff:ffff:ffff
24622f5::/1622f5:ffff:ffff:ffff:ffff:ffff:ffff:ffff
24722f6::/1622f6:ffff:ffff:ffff:ffff:ffff:ffff:ffff
24822f7::/1622f7:ffff:ffff:ffff:ffff:ffff:ffff:ffff
24922f8::/1622f8:ffff:ffff:ffff:ffff:ffff:ffff:ffff
25022f9::/1622f9:ffff:ffff:ffff:ffff:ffff:ffff:ffff
25122fa::/1622fa:ffff:ffff:ffff:ffff:ffff:ffff:ffff
25222fb::/1622fb:ffff:ffff:ffff:ffff:ffff:ffff:ffff
25322fc::/1622fc:ffff:ffff:ffff:ffff:ffff:ffff:ffff
25422fd::/1622fd:ffff:ffff:ffff:ffff:ffff:ffff:ffff
25522fe::/1622fe:ffff:ffff:ffff:ffff:ffff:ffff:ffff
25622ff::/1622ff: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.