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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/12
Addresses2^116
/64 networks2^52
Network
27a0::/12
First address
27a0::
Last address
27af: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
27a0:0000:0000:0000:0000:0000:0000:0000
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zone
a.7.2.ip6.arpa
Split into smaller subnets/20
/13 (2)/14 (4)/15 (8)/16 (16)/20 (256)/24 (4,096)/28 (65,536)

27a0::/12 makes 256 subnets of /20.

Subnets
#SubnetLast address
127a0::/2027a0:fff:ffff:ffff:ffff:ffff:ffff:ffff
227a0:1000::/2027a0:1fff:ffff:ffff:ffff:ffff:ffff:ffff
327a0:2000::/2027a0:2fff:ffff:ffff:ffff:ffff:ffff:ffff
427a0:3000::/2027a0:3fff:ffff:ffff:ffff:ffff:ffff:ffff
527a0:4000::/2027a0:4fff:ffff:ffff:ffff:ffff:ffff:ffff
627a0:5000::/2027a0:5fff:ffff:ffff:ffff:ffff:ffff:ffff
727a0:6000::/2027a0:6fff:ffff:ffff:ffff:ffff:ffff:ffff
827a0:7000::/2027a0:7fff:ffff:ffff:ffff:ffff:ffff:ffff
927a0:8000::/2027a0:8fff:ffff:ffff:ffff:ffff:ffff:ffff
1027a0:9000::/2027a0:9fff:ffff:ffff:ffff:ffff:ffff:ffff
1127a0:a000::/2027a0:afff:ffff:ffff:ffff:ffff:ffff:ffff
1227a0:b000::/2027a0:bfff:ffff:ffff:ffff:ffff:ffff:ffff
1327a0:c000::/2027a0:cfff:ffff:ffff:ffff:ffff:ffff:ffff
1427a0:d000::/2027a0:dfff:ffff:ffff:ffff:ffff:ffff:ffff
1527a0:e000::/2027a0:efff:ffff:ffff:ffff:ffff:ffff:ffff
1627a0:f000::/2027a0:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1727a1::/2027a1:fff:ffff:ffff:ffff:ffff:ffff:ffff
1827a1:1000::/2027a1:1fff:ffff:ffff:ffff:ffff:ffff:ffff
1927a1:2000::/2027a1:2fff:ffff:ffff:ffff:ffff:ffff:ffff
2027a1:3000::/2027a1:3fff:ffff:ffff:ffff:ffff:ffff:ffff
2127a1:4000::/2027a1:4fff:ffff:ffff:ffff:ffff:ffff:ffff
2227a1:5000::/2027a1:5fff:ffff:ffff:ffff:ffff:ffff:ffff
2327a1:6000::/2027a1:6fff:ffff:ffff:ffff:ffff:ffff:ffff
2427a1:7000::/2027a1:7fff:ffff:ffff:ffff:ffff:ffff:ffff
2527a1:8000::/2027a1:8fff:ffff:ffff:ffff:ffff:ffff:ffff
2627a1:9000::/2027a1:9fff:ffff:ffff:ffff:ffff:ffff:ffff
2727a1:a000::/2027a1:afff:ffff:ffff:ffff:ffff:ffff:ffff
2827a1:b000::/2027a1:bfff:ffff:ffff:ffff:ffff:ffff:ffff
2927a1:c000::/2027a1:cfff:ffff:ffff:ffff:ffff:ffff:ffff
3027a1:d000::/2027a1:dfff:ffff:ffff:ffff:ffff:ffff:ffff
3127a1:e000::/2027a1:efff:ffff:ffff:ffff:ffff:ffff:ffff
3227a1:f000::/2027a1:ffff:ffff:ffff:ffff:ffff:ffff:ffff
3327a2::/2027a2:fff:ffff:ffff:ffff:ffff:ffff:ffff
3427a2:1000::/2027a2:1fff:ffff:ffff:ffff:ffff:ffff:ffff
3527a2:2000::/2027a2:2fff:ffff:ffff:ffff:ffff:ffff:ffff
3627a2:3000::/2027a2:3fff:ffff:ffff:ffff:ffff:ffff:ffff
3727a2:4000::/2027a2:4fff:ffff:ffff:ffff:ffff:ffff:ffff
3827a2:5000::/2027a2:5fff:ffff:ffff:ffff:ffff:ffff:ffff
3927a2:6000::/2027a2:6fff:ffff:ffff:ffff:ffff:ffff:ffff
4027a2:7000::/2027a2:7fff:ffff:ffff:ffff:ffff:ffff:ffff
4127a2:8000::/2027a2:8fff:ffff:ffff:ffff:ffff:ffff:ffff
4227a2:9000::/2027a2:9fff:ffff:ffff:ffff:ffff:ffff:ffff
4327a2:a000::/2027a2:afff:ffff:ffff:ffff:ffff:ffff:ffff
4427a2:b000::/2027a2:bfff:ffff:ffff:ffff:ffff:ffff:ffff
4527a2:c000::/2027a2:cfff:ffff:ffff:ffff:ffff:ffff:ffff
4627a2:d000::/2027a2:dfff:ffff:ffff:ffff:ffff:ffff:ffff
4727a2:e000::/2027a2:efff:ffff:ffff:ffff:ffff:ffff:ffff
4827a2:f000::/2027a2:ffff:ffff:ffff:ffff:ffff:ffff:ffff
4927a3::/2027a3:fff:ffff:ffff:ffff:ffff:ffff:ffff
5027a3:1000::/2027a3:1fff:ffff:ffff:ffff:ffff:ffff:ffff
5127a3:2000::/2027a3:2fff:ffff:ffff:ffff:ffff:ffff:ffff
5227a3:3000::/2027a3:3fff:ffff:ffff:ffff:ffff:ffff:ffff
5327a3:4000::/2027a3:4fff:ffff:ffff:ffff:ffff:ffff:ffff
5427a3:5000::/2027a3:5fff:ffff:ffff:ffff:ffff:ffff:ffff
5527a3:6000::/2027a3:6fff:ffff:ffff:ffff:ffff:ffff:ffff
5627a3:7000::/2027a3:7fff:ffff:ffff:ffff:ffff:ffff:ffff
5727a3:8000::/2027a3:8fff:ffff:ffff:ffff:ffff:ffff:ffff
5827a3:9000::/2027a3:9fff:ffff:ffff:ffff:ffff:ffff:ffff
5927a3:a000::/2027a3:afff:ffff:ffff:ffff:ffff:ffff:ffff
6027a3:b000::/2027a3:bfff:ffff:ffff:ffff:ffff:ffff:ffff
6127a3:c000::/2027a3:cfff:ffff:ffff:ffff:ffff:ffff:ffff
6227a3:d000::/2027a3:dfff:ffff:ffff:ffff:ffff:ffff:ffff
6327a3:e000::/2027a3:efff:ffff:ffff:ffff:ffff:ffff:ffff
6427a3:f000::/2027a3:ffff:ffff:ffff:ffff:ffff:ffff:ffff
6527a4::/2027a4:fff:ffff:ffff:ffff:ffff:ffff:ffff
6627a4:1000::/2027a4:1fff:ffff:ffff:ffff:ffff:ffff:ffff
6727a4:2000::/2027a4:2fff:ffff:ffff:ffff:ffff:ffff:ffff
6827a4:3000::/2027a4:3fff:ffff:ffff:ffff:ffff:ffff:ffff
6927a4:4000::/2027a4:4fff:ffff:ffff:ffff:ffff:ffff:ffff
7027a4:5000::/2027a4:5fff:ffff:ffff:ffff:ffff:ffff:ffff
7127a4:6000::/2027a4:6fff:ffff:ffff:ffff:ffff:ffff:ffff
7227a4:7000::/2027a4:7fff:ffff:ffff:ffff:ffff:ffff:ffff
7327a4:8000::/2027a4:8fff:ffff:ffff:ffff:ffff:ffff:ffff
7427a4:9000::/2027a4:9fff:ffff:ffff:ffff:ffff:ffff:ffff
7527a4:a000::/2027a4:afff:ffff:ffff:ffff:ffff:ffff:ffff
7627a4:b000::/2027a4:bfff:ffff:ffff:ffff:ffff:ffff:ffff
7727a4:c000::/2027a4:cfff:ffff:ffff:ffff:ffff:ffff:ffff
7827a4:d000::/2027a4:dfff:ffff:ffff:ffff:ffff:ffff:ffff
7927a4:e000::/2027a4:efff:ffff:ffff:ffff:ffff:ffff:ffff
8027a4:f000::/2027a4:ffff:ffff:ffff:ffff:ffff:ffff:ffff
8127a5::/2027a5:fff:ffff:ffff:ffff:ffff:ffff:ffff
8227a5:1000::/2027a5:1fff:ffff:ffff:ffff:ffff:ffff:ffff
8327a5:2000::/2027a5:2fff:ffff:ffff:ffff:ffff:ffff:ffff
8427a5:3000::/2027a5:3fff:ffff:ffff:ffff:ffff:ffff:ffff
8527a5:4000::/2027a5:4fff:ffff:ffff:ffff:ffff:ffff:ffff
8627a5:5000::/2027a5:5fff:ffff:ffff:ffff:ffff:ffff:ffff
8727a5:6000::/2027a5:6fff:ffff:ffff:ffff:ffff:ffff:ffff
8827a5:7000::/2027a5:7fff:ffff:ffff:ffff:ffff:ffff:ffff
8927a5:8000::/2027a5:8fff:ffff:ffff:ffff:ffff:ffff:ffff
9027a5:9000::/2027a5:9fff:ffff:ffff:ffff:ffff:ffff:ffff
9127a5:a000::/2027a5:afff:ffff:ffff:ffff:ffff:ffff:ffff
9227a5:b000::/2027a5:bfff:ffff:ffff:ffff:ffff:ffff:ffff
9327a5:c000::/2027a5:cfff:ffff:ffff:ffff:ffff:ffff:ffff
9427a5:d000::/2027a5:dfff:ffff:ffff:ffff:ffff:ffff:ffff
9527a5:e000::/2027a5:efff:ffff:ffff:ffff:ffff:ffff:ffff
9627a5:f000::/2027a5:ffff:ffff:ffff:ffff:ffff:ffff:ffff
9727a6::/2027a6:fff:ffff:ffff:ffff:ffff:ffff:ffff
9827a6:1000::/2027a6:1fff:ffff:ffff:ffff:ffff:ffff:ffff
9927a6:2000::/2027a6:2fff:ffff:ffff:ffff:ffff:ffff:ffff
10027a6:3000::/2027a6:3fff:ffff:ffff:ffff:ffff:ffff:ffff
10127a6:4000::/2027a6:4fff:ffff:ffff:ffff:ffff:ffff:ffff
10227a6:5000::/2027a6:5fff:ffff:ffff:ffff:ffff:ffff:ffff
10327a6:6000::/2027a6:6fff:ffff:ffff:ffff:ffff:ffff:ffff
10427a6:7000::/2027a6:7fff:ffff:ffff:ffff:ffff:ffff:ffff
10527a6:8000::/2027a6:8fff:ffff:ffff:ffff:ffff:ffff:ffff
10627a6:9000::/2027a6:9fff:ffff:ffff:ffff:ffff:ffff:ffff
10727a6:a000::/2027a6:afff:ffff:ffff:ffff:ffff:ffff:ffff
10827a6:b000::/2027a6:bfff:ffff:ffff:ffff:ffff:ffff:ffff
10927a6:c000::/2027a6:cfff:ffff:ffff:ffff:ffff:ffff:ffff
11027a6:d000::/2027a6:dfff:ffff:ffff:ffff:ffff:ffff:ffff
11127a6:e000::/2027a6:efff:ffff:ffff:ffff:ffff:ffff:ffff
11227a6:f000::/2027a6:ffff:ffff:ffff:ffff:ffff:ffff:ffff
11327a7::/2027a7:fff:ffff:ffff:ffff:ffff:ffff:ffff
11427a7:1000::/2027a7:1fff:ffff:ffff:ffff:ffff:ffff:ffff
11527a7:2000::/2027a7:2fff:ffff:ffff:ffff:ffff:ffff:ffff
11627a7:3000::/2027a7:3fff:ffff:ffff:ffff:ffff:ffff:ffff
11727a7:4000::/2027a7:4fff:ffff:ffff:ffff:ffff:ffff:ffff
11827a7:5000::/2027a7:5fff:ffff:ffff:ffff:ffff:ffff:ffff
11927a7:6000::/2027a7:6fff:ffff:ffff:ffff:ffff:ffff:ffff
12027a7:7000::/2027a7:7fff:ffff:ffff:ffff:ffff:ffff:ffff
12127a7:8000::/2027a7:8fff:ffff:ffff:ffff:ffff:ffff:ffff
12227a7:9000::/2027a7:9fff:ffff:ffff:ffff:ffff:ffff:ffff
12327a7:a000::/2027a7:afff:ffff:ffff:ffff:ffff:ffff:ffff
12427a7:b000::/2027a7:bfff:ffff:ffff:ffff:ffff:ffff:ffff
12527a7:c000::/2027a7:cfff:ffff:ffff:ffff:ffff:ffff:ffff
12627a7:d000::/2027a7:dfff:ffff:ffff:ffff:ffff:ffff:ffff
12727a7:e000::/2027a7:efff:ffff:ffff:ffff:ffff:ffff:ffff
12827a7:f000::/2027a7:ffff:ffff:ffff:ffff:ffff:ffff:ffff
12927a8::/2027a8:fff:ffff:ffff:ffff:ffff:ffff:ffff
13027a8:1000::/2027a8:1fff:ffff:ffff:ffff:ffff:ffff:ffff
13127a8:2000::/2027a8:2fff:ffff:ffff:ffff:ffff:ffff:ffff
13227a8:3000::/2027a8:3fff:ffff:ffff:ffff:ffff:ffff:ffff
13327a8:4000::/2027a8:4fff:ffff:ffff:ffff:ffff:ffff:ffff
13427a8:5000::/2027a8:5fff:ffff:ffff:ffff:ffff:ffff:ffff
13527a8:6000::/2027a8:6fff:ffff:ffff:ffff:ffff:ffff:ffff
13627a8:7000::/2027a8:7fff:ffff:ffff:ffff:ffff:ffff:ffff
13727a8:8000::/2027a8:8fff:ffff:ffff:ffff:ffff:ffff:ffff
13827a8:9000::/2027a8:9fff:ffff:ffff:ffff:ffff:ffff:ffff
13927a8:a000::/2027a8:afff:ffff:ffff:ffff:ffff:ffff:ffff
14027a8:b000::/2027a8:bfff:ffff:ffff:ffff:ffff:ffff:ffff
14127a8:c000::/2027a8:cfff:ffff:ffff:ffff:ffff:ffff:ffff
14227a8:d000::/2027a8:dfff:ffff:ffff:ffff:ffff:ffff:ffff
14327a8:e000::/2027a8:efff:ffff:ffff:ffff:ffff:ffff:ffff
14427a8:f000::/2027a8:ffff:ffff:ffff:ffff:ffff:ffff:ffff
14527a9::/2027a9:fff:ffff:ffff:ffff:ffff:ffff:ffff
14627a9:1000::/2027a9:1fff:ffff:ffff:ffff:ffff:ffff:ffff
14727a9:2000::/2027a9:2fff:ffff:ffff:ffff:ffff:ffff:ffff
14827a9:3000::/2027a9:3fff:ffff:ffff:ffff:ffff:ffff:ffff
14927a9:4000::/2027a9:4fff:ffff:ffff:ffff:ffff:ffff:ffff
15027a9:5000::/2027a9:5fff:ffff:ffff:ffff:ffff:ffff:ffff
15127a9:6000::/2027a9:6fff:ffff:ffff:ffff:ffff:ffff:ffff
15227a9:7000::/2027a9:7fff:ffff:ffff:ffff:ffff:ffff:ffff
15327a9:8000::/2027a9:8fff:ffff:ffff:ffff:ffff:ffff:ffff
15427a9:9000::/2027a9:9fff:ffff:ffff:ffff:ffff:ffff:ffff
15527a9:a000::/2027a9:afff:ffff:ffff:ffff:ffff:ffff:ffff
15627a9:b000::/2027a9:bfff:ffff:ffff:ffff:ffff:ffff:ffff
15727a9:c000::/2027a9:cfff:ffff:ffff:ffff:ffff:ffff:ffff
15827a9:d000::/2027a9:dfff:ffff:ffff:ffff:ffff:ffff:ffff
15927a9:e000::/2027a9:efff:ffff:ffff:ffff:ffff:ffff:ffff
16027a9:f000::/2027a9:ffff:ffff:ffff:ffff:ffff:ffff:ffff
16127aa::/2027aa:fff:ffff:ffff:ffff:ffff:ffff:ffff
16227aa:1000::/2027aa:1fff:ffff:ffff:ffff:ffff:ffff:ffff
16327aa:2000::/2027aa:2fff:ffff:ffff:ffff:ffff:ffff:ffff
16427aa:3000::/2027aa:3fff:ffff:ffff:ffff:ffff:ffff:ffff
16527aa:4000::/2027aa:4fff:ffff:ffff:ffff:ffff:ffff:ffff
16627aa:5000::/2027aa:5fff:ffff:ffff:ffff:ffff:ffff:ffff
16727aa:6000::/2027aa:6fff:ffff:ffff:ffff:ffff:ffff:ffff
16827aa:7000::/2027aa:7fff:ffff:ffff:ffff:ffff:ffff:ffff
16927aa:8000::/2027aa:8fff:ffff:ffff:ffff:ffff:ffff:ffff
17027aa:9000::/2027aa:9fff:ffff:ffff:ffff:ffff:ffff:ffff
17127aa:a000::/2027aa:afff:ffff:ffff:ffff:ffff:ffff:ffff
17227aa:b000::/2027aa:bfff:ffff:ffff:ffff:ffff:ffff:ffff
17327aa:c000::/2027aa:cfff:ffff:ffff:ffff:ffff:ffff:ffff
17427aa:d000::/2027aa:dfff:ffff:ffff:ffff:ffff:ffff:ffff
17527aa:e000::/2027aa:efff:ffff:ffff:ffff:ffff:ffff:ffff
17627aa:f000::/2027aa:ffff:ffff:ffff:ffff:ffff:ffff:ffff
17727ab::/2027ab:fff:ffff:ffff:ffff:ffff:ffff:ffff
17827ab:1000::/2027ab:1fff:ffff:ffff:ffff:ffff:ffff:ffff
17927ab:2000::/2027ab:2fff:ffff:ffff:ffff:ffff:ffff:ffff
18027ab:3000::/2027ab:3fff:ffff:ffff:ffff:ffff:ffff:ffff
18127ab:4000::/2027ab:4fff:ffff:ffff:ffff:ffff:ffff:ffff
18227ab:5000::/2027ab:5fff:ffff:ffff:ffff:ffff:ffff:ffff
18327ab:6000::/2027ab:6fff:ffff:ffff:ffff:ffff:ffff:ffff
18427ab:7000::/2027ab:7fff:ffff:ffff:ffff:ffff:ffff:ffff
18527ab:8000::/2027ab:8fff:ffff:ffff:ffff:ffff:ffff:ffff
18627ab:9000::/2027ab:9fff:ffff:ffff:ffff:ffff:ffff:ffff
18727ab:a000::/2027ab:afff:ffff:ffff:ffff:ffff:ffff:ffff
18827ab:b000::/2027ab:bfff:ffff:ffff:ffff:ffff:ffff:ffff
18927ab:c000::/2027ab:cfff:ffff:ffff:ffff:ffff:ffff:ffff
19027ab:d000::/2027ab:dfff:ffff:ffff:ffff:ffff:ffff:ffff
19127ab:e000::/2027ab:efff:ffff:ffff:ffff:ffff:ffff:ffff
19227ab:f000::/2027ab:ffff:ffff:ffff:ffff:ffff:ffff:ffff
19327ac::/2027ac:fff:ffff:ffff:ffff:ffff:ffff:ffff
19427ac:1000::/2027ac:1fff:ffff:ffff:ffff:ffff:ffff:ffff
19527ac:2000::/2027ac:2fff:ffff:ffff:ffff:ffff:ffff:ffff
19627ac:3000::/2027ac:3fff:ffff:ffff:ffff:ffff:ffff:ffff
19727ac:4000::/2027ac:4fff:ffff:ffff:ffff:ffff:ffff:ffff
19827ac:5000::/2027ac:5fff:ffff:ffff:ffff:ffff:ffff:ffff
19927ac:6000::/2027ac:6fff:ffff:ffff:ffff:ffff:ffff:ffff
20027ac:7000::/2027ac:7fff:ffff:ffff:ffff:ffff:ffff:ffff
20127ac:8000::/2027ac:8fff:ffff:ffff:ffff:ffff:ffff:ffff
20227ac:9000::/2027ac:9fff:ffff:ffff:ffff:ffff:ffff:ffff
20327ac:a000::/2027ac:afff:ffff:ffff:ffff:ffff:ffff:ffff
20427ac:b000::/2027ac:bfff:ffff:ffff:ffff:ffff:ffff:ffff
20527ac:c000::/2027ac:cfff:ffff:ffff:ffff:ffff:ffff:ffff
20627ac:d000::/2027ac:dfff:ffff:ffff:ffff:ffff:ffff:ffff
20727ac:e000::/2027ac:efff:ffff:ffff:ffff:ffff:ffff:ffff
20827ac:f000::/2027ac:ffff:ffff:ffff:ffff:ffff:ffff:ffff
20927ad::/2027ad:fff:ffff:ffff:ffff:ffff:ffff:ffff
21027ad:1000::/2027ad:1fff:ffff:ffff:ffff:ffff:ffff:ffff
21127ad:2000::/2027ad:2fff:ffff:ffff:ffff:ffff:ffff:ffff
21227ad:3000::/2027ad:3fff:ffff:ffff:ffff:ffff:ffff:ffff
21327ad:4000::/2027ad:4fff:ffff:ffff:ffff:ffff:ffff:ffff
21427ad:5000::/2027ad:5fff:ffff:ffff:ffff:ffff:ffff:ffff
21527ad:6000::/2027ad:6fff:ffff:ffff:ffff:ffff:ffff:ffff
21627ad:7000::/2027ad:7fff:ffff:ffff:ffff:ffff:ffff:ffff
21727ad:8000::/2027ad:8fff:ffff:ffff:ffff:ffff:ffff:ffff
21827ad:9000::/2027ad:9fff:ffff:ffff:ffff:ffff:ffff:ffff
21927ad:a000::/2027ad:afff:ffff:ffff:ffff:ffff:ffff:ffff
22027ad:b000::/2027ad:bfff:ffff:ffff:ffff:ffff:ffff:ffff
22127ad:c000::/2027ad:cfff:ffff:ffff:ffff:ffff:ffff:ffff
22227ad:d000::/2027ad:dfff:ffff:ffff:ffff:ffff:ffff:ffff
22327ad:e000::/2027ad:efff:ffff:ffff:ffff:ffff:ffff:ffff
22427ad:f000::/2027ad:ffff:ffff:ffff:ffff:ffff:ffff:ffff
22527ae::/2027ae:fff:ffff:ffff:ffff:ffff:ffff:ffff
22627ae:1000::/2027ae:1fff:ffff:ffff:ffff:ffff:ffff:ffff
22727ae:2000::/2027ae:2fff:ffff:ffff:ffff:ffff:ffff:ffff
22827ae:3000::/2027ae:3fff:ffff:ffff:ffff:ffff:ffff:ffff
22927ae:4000::/2027ae:4fff:ffff:ffff:ffff:ffff:ffff:ffff
23027ae:5000::/2027ae:5fff:ffff:ffff:ffff:ffff:ffff:ffff
23127ae:6000::/2027ae:6fff:ffff:ffff:ffff:ffff:ffff:ffff
23227ae:7000::/2027ae:7fff:ffff:ffff:ffff:ffff:ffff:ffff
23327ae:8000::/2027ae:8fff:ffff:ffff:ffff:ffff:ffff:ffff
23427ae:9000::/2027ae:9fff:ffff:ffff:ffff:ffff:ffff:ffff
23527ae:a000::/2027ae:afff:ffff:ffff:ffff:ffff:ffff:ffff
23627ae:b000::/2027ae:bfff:ffff:ffff:ffff:ffff:ffff:ffff
23727ae:c000::/2027ae:cfff:ffff:ffff:ffff:ffff:ffff:ffff
23827ae:d000::/2027ae:dfff:ffff:ffff:ffff:ffff:ffff:ffff
23927ae:e000::/2027ae:efff:ffff:ffff:ffff:ffff:ffff:ffff
24027ae:f000::/2027ae:ffff:ffff:ffff:ffff:ffff:ffff:ffff
24127af::/2027af:fff:ffff:ffff:ffff:ffff:ffff:ffff
24227af:1000::/2027af:1fff:ffff:ffff:ffff:ffff:ffff:ffff
24327af:2000::/2027af:2fff:ffff:ffff:ffff:ffff:ffff:ffff
24427af:3000::/2027af:3fff:ffff:ffff:ffff:ffff:ffff:ffff
24527af:4000::/2027af:4fff:ffff:ffff:ffff:ffff:ffff:ffff
24627af:5000::/2027af:5fff:ffff:ffff:ffff:ffff:ffff:ffff
24727af:6000::/2027af:6fff:ffff:ffff:ffff:ffff:ffff:ffff
24827af:7000::/2027af:7fff:ffff:ffff:ffff:ffff:ffff:ffff
24927af:8000::/2027af:8fff:ffff:ffff:ffff:ffff:ffff:ffff
25027af:9000::/2027af:9fff:ffff:ffff:ffff:ffff:ffff:ffff
25127af:a000::/2027af:afff:ffff:ffff:ffff:ffff:ffff:ffff
25227af:b000::/2027af:bfff:ffff:ffff:ffff:ffff:ffff:ffff
25327af:c000::/2027af:cfff:ffff:ffff:ffff:ffff:ffff:ffff
25427af:d000::/2027af:dfff:ffff:ffff:ffff:ffff:ffff:ffff
25527af:e000::/2027af:efff:ffff:ffff:ffff:ffff:ffff:ffff
25627af:f000::/2027af: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.