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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.

Network75.49.0.0/17
Usable hosts32,766
Subnet mask255.255.128.0
Addresses32,768
Network address
75.49.0.0
Broadcast address
75.49.127.255
First usable
75.49.0.1
Last usable
75.49.127.254
Usable hosts
32,766 (32,768 less the network and broadcast addresses)
Subnet mask
255.255.128.0
Wildcard mask
0.0.127.255 (Cisco ACLs, OSPF)
Prefix length
/17
Type
Public public
Old class
A (default /8)
As numbers
Hex 4B310000 · Integer 1261502464 to 1261535231
Reverse DNS zones
0.49.75.in-addr.arpa
1.49.75.in-addr.arpa
2.49.75.in-addr.arpa
3.49.75.in-addr.arpa
4.49.75.in-addr.arpa
5.49.75.in-addr.arpa
6.49.75.in-addr.arpa
7.49.75.in-addr.arpa
8.49.75.in-addr.arpa
9.49.75.in-addr.arpa
10.49.75.in-addr.arpa
11.49.75.in-addr.arpa
12.49.75.in-addr.arpa
13.49.75.in-addr.arpa
14.49.75.in-addr.arpa
15.49.75.in-addr.arpa
and 112 more
/17 is not on a 8-bit boundary, so it takes 128 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01001011.00110001.00000000.0000000075.49.0.0
Subnet mask11111111.11111111.10000000.00000000255.255.128.0
Network01001011.00110001.00000000.0000000075.49.0.0
Broadcast01001011.00110001.01111111.1111111175.49.127.255
Split into smaller subnets/26
/18 (2)/19 (4)/20 (8)/21 (16)/22 (32)/23 (64)/24 (128)/25 (256)/26 (512)/27 (1,024)/28 (2,048)/29 (4,096)

75.49.0.0/17 makes 512 subnets of /26; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
175.49.0.0/2675.49.0.1 to 75.49.0.6275.49.0.6362
275.49.0.64/2675.49.0.65 to 75.49.0.12675.49.0.12762
375.49.0.128/2675.49.0.129 to 75.49.0.19075.49.0.19162
475.49.0.192/2675.49.0.193 to 75.49.0.25475.49.0.25562
575.49.1.0/2675.49.1.1 to 75.49.1.6275.49.1.6362
675.49.1.64/2675.49.1.65 to 75.49.1.12675.49.1.12762
775.49.1.128/2675.49.1.129 to 75.49.1.19075.49.1.19162
875.49.1.192/2675.49.1.193 to 75.49.1.25475.49.1.25562
975.49.2.0/2675.49.2.1 to 75.49.2.6275.49.2.6362
1075.49.2.64/2675.49.2.65 to 75.49.2.12675.49.2.12762
1175.49.2.128/2675.49.2.129 to 75.49.2.19075.49.2.19162
1275.49.2.192/2675.49.2.193 to 75.49.2.25475.49.2.25562
1375.49.3.0/2675.49.3.1 to 75.49.3.6275.49.3.6362
1475.49.3.64/2675.49.3.65 to 75.49.3.12675.49.3.12762
1575.49.3.128/2675.49.3.129 to 75.49.3.19075.49.3.19162
1675.49.3.192/2675.49.3.193 to 75.49.3.25475.49.3.25562
1775.49.4.0/2675.49.4.1 to 75.49.4.6275.49.4.6362
1875.49.4.64/2675.49.4.65 to 75.49.4.12675.49.4.12762
1975.49.4.128/2675.49.4.129 to 75.49.4.19075.49.4.19162
2075.49.4.192/2675.49.4.193 to 75.49.4.25475.49.4.25562
2175.49.5.0/2675.49.5.1 to 75.49.5.6275.49.5.6362
2275.49.5.64/2675.49.5.65 to 75.49.5.12675.49.5.12762
2375.49.5.128/2675.49.5.129 to 75.49.5.19075.49.5.19162
2475.49.5.192/2675.49.5.193 to 75.49.5.25475.49.5.25562
2575.49.6.0/2675.49.6.1 to 75.49.6.6275.49.6.6362
2675.49.6.64/2675.49.6.65 to 75.49.6.12675.49.6.12762
2775.49.6.128/2675.49.6.129 to 75.49.6.19075.49.6.19162
2875.49.6.192/2675.49.6.193 to 75.49.6.25475.49.6.25562
2975.49.7.0/2675.49.7.1 to 75.49.7.6275.49.7.6362
3075.49.7.64/2675.49.7.65 to 75.49.7.12675.49.7.12762
3175.49.7.128/2675.49.7.129 to 75.49.7.19075.49.7.19162
3275.49.7.192/2675.49.7.193 to 75.49.7.25475.49.7.25562
3375.49.8.0/2675.49.8.1 to 75.49.8.6275.49.8.6362
3475.49.8.64/2675.49.8.65 to 75.49.8.12675.49.8.12762
3575.49.8.128/2675.49.8.129 to 75.49.8.19075.49.8.19162
3675.49.8.192/2675.49.8.193 to 75.49.8.25475.49.8.25562
3775.49.9.0/2675.49.9.1 to 75.49.9.6275.49.9.6362
3875.49.9.64/2675.49.9.65 to 75.49.9.12675.49.9.12762
3975.49.9.128/2675.49.9.129 to 75.49.9.19075.49.9.19162
4075.49.9.192/2675.49.9.193 to 75.49.9.25475.49.9.25562
4175.49.10.0/2675.49.10.1 to 75.49.10.6275.49.10.6362
4275.49.10.64/2675.49.10.65 to 75.49.10.12675.49.10.12762
4375.49.10.128/2675.49.10.129 to 75.49.10.19075.49.10.19162
4475.49.10.192/2675.49.10.193 to 75.49.10.25475.49.10.25562
4575.49.11.0/2675.49.11.1 to 75.49.11.6275.49.11.6362
4675.49.11.64/2675.49.11.65 to 75.49.11.12675.49.11.12762
4775.49.11.128/2675.49.11.129 to 75.49.11.19075.49.11.19162
4875.49.11.192/2675.49.11.193 to 75.49.11.25475.49.11.25562
4975.49.12.0/2675.49.12.1 to 75.49.12.6275.49.12.6362
5075.49.12.64/2675.49.12.65 to 75.49.12.12675.49.12.12762
5175.49.12.128/2675.49.12.129 to 75.49.12.19075.49.12.19162
5275.49.12.192/2675.49.12.193 to 75.49.12.25475.49.12.25562
5375.49.13.0/2675.49.13.1 to 75.49.13.6275.49.13.6362
5475.49.13.64/2675.49.13.65 to 75.49.13.12675.49.13.12762
5575.49.13.128/2675.49.13.129 to 75.49.13.19075.49.13.19162
5675.49.13.192/2675.49.13.193 to 75.49.13.25475.49.13.25562
5775.49.14.0/2675.49.14.1 to 75.49.14.6275.49.14.6362
5875.49.14.64/2675.49.14.65 to 75.49.14.12675.49.14.12762
5975.49.14.128/2675.49.14.129 to 75.49.14.19075.49.14.19162
6075.49.14.192/2675.49.14.193 to 75.49.14.25475.49.14.25562
6175.49.15.0/2675.49.15.1 to 75.49.15.6275.49.15.6362
6275.49.15.64/2675.49.15.65 to 75.49.15.12675.49.15.12762
6375.49.15.128/2675.49.15.129 to 75.49.15.19075.49.15.19162
6475.49.15.192/2675.49.15.193 to 75.49.15.25475.49.15.25562
6575.49.16.0/2675.49.16.1 to 75.49.16.6275.49.16.6362
6675.49.16.64/2675.49.16.65 to 75.49.16.12675.49.16.12762
6775.49.16.128/2675.49.16.129 to 75.49.16.19075.49.16.19162
6875.49.16.192/2675.49.16.193 to 75.49.16.25475.49.16.25562
6975.49.17.0/2675.49.17.1 to 75.49.17.6275.49.17.6362
7075.49.17.64/2675.49.17.65 to 75.49.17.12675.49.17.12762
7175.49.17.128/2675.49.17.129 to 75.49.17.19075.49.17.19162
7275.49.17.192/2675.49.17.193 to 75.49.17.25475.49.17.25562
7375.49.18.0/2675.49.18.1 to 75.49.18.6275.49.18.6362
7475.49.18.64/2675.49.18.65 to 75.49.18.12675.49.18.12762
7575.49.18.128/2675.49.18.129 to 75.49.18.19075.49.18.19162
7675.49.18.192/2675.49.18.193 to 75.49.18.25475.49.18.25562
7775.49.19.0/2675.49.19.1 to 75.49.19.6275.49.19.6362
7875.49.19.64/2675.49.19.65 to 75.49.19.12675.49.19.12762
7975.49.19.128/2675.49.19.129 to 75.49.19.19075.49.19.19162
8075.49.19.192/2675.49.19.193 to 75.49.19.25475.49.19.25562
8175.49.20.0/2675.49.20.1 to 75.49.20.6275.49.20.6362
8275.49.20.64/2675.49.20.65 to 75.49.20.12675.49.20.12762
8375.49.20.128/2675.49.20.129 to 75.49.20.19075.49.20.19162
8475.49.20.192/2675.49.20.193 to 75.49.20.25475.49.20.25562
8575.49.21.0/2675.49.21.1 to 75.49.21.6275.49.21.6362
8675.49.21.64/2675.49.21.65 to 75.49.21.12675.49.21.12762
8775.49.21.128/2675.49.21.129 to 75.49.21.19075.49.21.19162
8875.49.21.192/2675.49.21.193 to 75.49.21.25475.49.21.25562
8975.49.22.0/2675.49.22.1 to 75.49.22.6275.49.22.6362
9075.49.22.64/2675.49.22.65 to 75.49.22.12675.49.22.12762
9175.49.22.128/2675.49.22.129 to 75.49.22.19075.49.22.19162
9275.49.22.192/2675.49.22.193 to 75.49.22.25475.49.22.25562
9375.49.23.0/2675.49.23.1 to 75.49.23.6275.49.23.6362
9475.49.23.64/2675.49.23.65 to 75.49.23.12675.49.23.12762
9575.49.23.128/2675.49.23.129 to 75.49.23.19075.49.23.19162
9675.49.23.192/2675.49.23.193 to 75.49.23.25475.49.23.25562
9775.49.24.0/2675.49.24.1 to 75.49.24.6275.49.24.6362
9875.49.24.64/2675.49.24.65 to 75.49.24.12675.49.24.12762
9975.49.24.128/2675.49.24.129 to 75.49.24.19075.49.24.19162
10075.49.24.192/2675.49.24.193 to 75.49.24.25475.49.24.25562
10175.49.25.0/2675.49.25.1 to 75.49.25.6275.49.25.6362
10275.49.25.64/2675.49.25.65 to 75.49.25.12675.49.25.12762
10375.49.25.128/2675.49.25.129 to 75.49.25.19075.49.25.19162
10475.49.25.192/2675.49.25.193 to 75.49.25.25475.49.25.25562
10575.49.26.0/2675.49.26.1 to 75.49.26.6275.49.26.6362
10675.49.26.64/2675.49.26.65 to 75.49.26.12675.49.26.12762
10775.49.26.128/2675.49.26.129 to 75.49.26.19075.49.26.19162
10875.49.26.192/2675.49.26.193 to 75.49.26.25475.49.26.25562
10975.49.27.0/2675.49.27.1 to 75.49.27.6275.49.27.6362
11075.49.27.64/2675.49.27.65 to 75.49.27.12675.49.27.12762
11175.49.27.128/2675.49.27.129 to 75.49.27.19075.49.27.19162
11275.49.27.192/2675.49.27.193 to 75.49.27.25475.49.27.25562
11375.49.28.0/2675.49.28.1 to 75.49.28.6275.49.28.6362
11475.49.28.64/2675.49.28.65 to 75.49.28.12675.49.28.12762
11575.49.28.128/2675.49.28.129 to 75.49.28.19075.49.28.19162
11675.49.28.192/2675.49.28.193 to 75.49.28.25475.49.28.25562
11775.49.29.0/2675.49.29.1 to 75.49.29.6275.49.29.6362
11875.49.29.64/2675.49.29.65 to 75.49.29.12675.49.29.12762
11975.49.29.128/2675.49.29.129 to 75.49.29.19075.49.29.19162
12075.49.29.192/2675.49.29.193 to 75.49.29.25475.49.29.25562
12175.49.30.0/2675.49.30.1 to 75.49.30.6275.49.30.6362
12275.49.30.64/2675.49.30.65 to 75.49.30.12675.49.30.12762
12375.49.30.128/2675.49.30.129 to 75.49.30.19075.49.30.19162
12475.49.30.192/2675.49.30.193 to 75.49.30.25475.49.30.25562
12575.49.31.0/2675.49.31.1 to 75.49.31.6275.49.31.6362
12675.49.31.64/2675.49.31.65 to 75.49.31.12675.49.31.12762
12775.49.31.128/2675.49.31.129 to 75.49.31.19075.49.31.19162
12875.49.31.192/2675.49.31.193 to 75.49.31.25475.49.31.25562
12975.49.32.0/2675.49.32.1 to 75.49.32.6275.49.32.6362
13075.49.32.64/2675.49.32.65 to 75.49.32.12675.49.32.12762
13175.49.32.128/2675.49.32.129 to 75.49.32.19075.49.32.19162
13275.49.32.192/2675.49.32.193 to 75.49.32.25475.49.32.25562
13375.49.33.0/2675.49.33.1 to 75.49.33.6275.49.33.6362
13475.49.33.64/2675.49.33.65 to 75.49.33.12675.49.33.12762
13575.49.33.128/2675.49.33.129 to 75.49.33.19075.49.33.19162
13675.49.33.192/2675.49.33.193 to 75.49.33.25475.49.33.25562
13775.49.34.0/2675.49.34.1 to 75.49.34.6275.49.34.6362
13875.49.34.64/2675.49.34.65 to 75.49.34.12675.49.34.12762
13975.49.34.128/2675.49.34.129 to 75.49.34.19075.49.34.19162
14075.49.34.192/2675.49.34.193 to 75.49.34.25475.49.34.25562
14175.49.35.0/2675.49.35.1 to 75.49.35.6275.49.35.6362
14275.49.35.64/2675.49.35.65 to 75.49.35.12675.49.35.12762
14375.49.35.128/2675.49.35.129 to 75.49.35.19075.49.35.19162
14475.49.35.192/2675.49.35.193 to 75.49.35.25475.49.35.25562
14575.49.36.0/2675.49.36.1 to 75.49.36.6275.49.36.6362
14675.49.36.64/2675.49.36.65 to 75.49.36.12675.49.36.12762
14775.49.36.128/2675.49.36.129 to 75.49.36.19075.49.36.19162
14875.49.36.192/2675.49.36.193 to 75.49.36.25475.49.36.25562
14975.49.37.0/2675.49.37.1 to 75.49.37.6275.49.37.6362
15075.49.37.64/2675.49.37.65 to 75.49.37.12675.49.37.12762
15175.49.37.128/2675.49.37.129 to 75.49.37.19075.49.37.19162
15275.49.37.192/2675.49.37.193 to 75.49.37.25475.49.37.25562
15375.49.38.0/2675.49.38.1 to 75.49.38.6275.49.38.6362
15475.49.38.64/2675.49.38.65 to 75.49.38.12675.49.38.12762
15575.49.38.128/2675.49.38.129 to 75.49.38.19075.49.38.19162
15675.49.38.192/2675.49.38.193 to 75.49.38.25475.49.38.25562
15775.49.39.0/2675.49.39.1 to 75.49.39.6275.49.39.6362
15875.49.39.64/2675.49.39.65 to 75.49.39.12675.49.39.12762
15975.49.39.128/2675.49.39.129 to 75.49.39.19075.49.39.19162
16075.49.39.192/2675.49.39.193 to 75.49.39.25475.49.39.25562
16175.49.40.0/2675.49.40.1 to 75.49.40.6275.49.40.6362
16275.49.40.64/2675.49.40.65 to 75.49.40.12675.49.40.12762
16375.49.40.128/2675.49.40.129 to 75.49.40.19075.49.40.19162
16475.49.40.192/2675.49.40.193 to 75.49.40.25475.49.40.25562
16575.49.41.0/2675.49.41.1 to 75.49.41.6275.49.41.6362
16675.49.41.64/2675.49.41.65 to 75.49.41.12675.49.41.12762
16775.49.41.128/2675.49.41.129 to 75.49.41.19075.49.41.19162
16875.49.41.192/2675.49.41.193 to 75.49.41.25475.49.41.25562
16975.49.42.0/2675.49.42.1 to 75.49.42.6275.49.42.6362
17075.49.42.64/2675.49.42.65 to 75.49.42.12675.49.42.12762
17175.49.42.128/2675.49.42.129 to 75.49.42.19075.49.42.19162
17275.49.42.192/2675.49.42.193 to 75.49.42.25475.49.42.25562
17375.49.43.0/2675.49.43.1 to 75.49.43.6275.49.43.6362
17475.49.43.64/2675.49.43.65 to 75.49.43.12675.49.43.12762
17575.49.43.128/2675.49.43.129 to 75.49.43.19075.49.43.19162
17675.49.43.192/2675.49.43.193 to 75.49.43.25475.49.43.25562
17775.49.44.0/2675.49.44.1 to 75.49.44.6275.49.44.6362
17875.49.44.64/2675.49.44.65 to 75.49.44.12675.49.44.12762
17975.49.44.128/2675.49.44.129 to 75.49.44.19075.49.44.19162
18075.49.44.192/2675.49.44.193 to 75.49.44.25475.49.44.25562
18175.49.45.0/2675.49.45.1 to 75.49.45.6275.49.45.6362
18275.49.45.64/2675.49.45.65 to 75.49.45.12675.49.45.12762
18375.49.45.128/2675.49.45.129 to 75.49.45.19075.49.45.19162
18475.49.45.192/2675.49.45.193 to 75.49.45.25475.49.45.25562
18575.49.46.0/2675.49.46.1 to 75.49.46.6275.49.46.6362
18675.49.46.64/2675.49.46.65 to 75.49.46.12675.49.46.12762
18775.49.46.128/2675.49.46.129 to 75.49.46.19075.49.46.19162
18875.49.46.192/2675.49.46.193 to 75.49.46.25475.49.46.25562
18975.49.47.0/2675.49.47.1 to 75.49.47.6275.49.47.6362
19075.49.47.64/2675.49.47.65 to 75.49.47.12675.49.47.12762
19175.49.47.128/2675.49.47.129 to 75.49.47.19075.49.47.19162
19275.49.47.192/2675.49.47.193 to 75.49.47.25475.49.47.25562
19375.49.48.0/2675.49.48.1 to 75.49.48.6275.49.48.6362
19475.49.48.64/2675.49.48.65 to 75.49.48.12675.49.48.12762
19575.49.48.128/2675.49.48.129 to 75.49.48.19075.49.48.19162
19675.49.48.192/2675.49.48.193 to 75.49.48.25475.49.48.25562
19775.49.49.0/2675.49.49.1 to 75.49.49.6275.49.49.6362
19875.49.49.64/2675.49.49.65 to 75.49.49.12675.49.49.12762
19975.49.49.128/2675.49.49.129 to 75.49.49.19075.49.49.19162
20075.49.49.192/2675.49.49.193 to 75.49.49.25475.49.49.25562
20175.49.50.0/2675.49.50.1 to 75.49.50.6275.49.50.6362
20275.49.50.64/2675.49.50.65 to 75.49.50.12675.49.50.12762
20375.49.50.128/2675.49.50.129 to 75.49.50.19075.49.50.19162
20475.49.50.192/2675.49.50.193 to 75.49.50.25475.49.50.25562
20575.49.51.0/2675.49.51.1 to 75.49.51.6275.49.51.6362
20675.49.51.64/2675.49.51.65 to 75.49.51.12675.49.51.12762
20775.49.51.128/2675.49.51.129 to 75.49.51.19075.49.51.19162
20875.49.51.192/2675.49.51.193 to 75.49.51.25475.49.51.25562
20975.49.52.0/2675.49.52.1 to 75.49.52.6275.49.52.6362
21075.49.52.64/2675.49.52.65 to 75.49.52.12675.49.52.12762
21175.49.52.128/2675.49.52.129 to 75.49.52.19075.49.52.19162
21275.49.52.192/2675.49.52.193 to 75.49.52.25475.49.52.25562
21375.49.53.0/2675.49.53.1 to 75.49.53.6275.49.53.6362
21475.49.53.64/2675.49.53.65 to 75.49.53.12675.49.53.12762
21575.49.53.128/2675.49.53.129 to 75.49.53.19075.49.53.19162
21675.49.53.192/2675.49.53.193 to 75.49.53.25475.49.53.25562
21775.49.54.0/2675.49.54.1 to 75.49.54.6275.49.54.6362
21875.49.54.64/2675.49.54.65 to 75.49.54.12675.49.54.12762
21975.49.54.128/2675.49.54.129 to 75.49.54.19075.49.54.19162
22075.49.54.192/2675.49.54.193 to 75.49.54.25475.49.54.25562
22175.49.55.0/2675.49.55.1 to 75.49.55.6275.49.55.6362
22275.49.55.64/2675.49.55.65 to 75.49.55.12675.49.55.12762
22375.49.55.128/2675.49.55.129 to 75.49.55.19075.49.55.19162
22475.49.55.192/2675.49.55.193 to 75.49.55.25475.49.55.25562
22575.49.56.0/2675.49.56.1 to 75.49.56.6275.49.56.6362
22675.49.56.64/2675.49.56.65 to 75.49.56.12675.49.56.12762
22775.49.56.128/2675.49.56.129 to 75.49.56.19075.49.56.19162
22875.49.56.192/2675.49.56.193 to 75.49.56.25475.49.56.25562
22975.49.57.0/2675.49.57.1 to 75.49.57.6275.49.57.6362
23075.49.57.64/2675.49.57.65 to 75.49.57.12675.49.57.12762
23175.49.57.128/2675.49.57.129 to 75.49.57.19075.49.57.19162
23275.49.57.192/2675.49.57.193 to 75.49.57.25475.49.57.25562
23375.49.58.0/2675.49.58.1 to 75.49.58.6275.49.58.6362
23475.49.58.64/2675.49.58.65 to 75.49.58.12675.49.58.12762
23575.49.58.128/2675.49.58.129 to 75.49.58.19075.49.58.19162
23675.49.58.192/2675.49.58.193 to 75.49.58.25475.49.58.25562
23775.49.59.0/2675.49.59.1 to 75.49.59.6275.49.59.6362
23875.49.59.64/2675.49.59.65 to 75.49.59.12675.49.59.12762
23975.49.59.128/2675.49.59.129 to 75.49.59.19075.49.59.19162
24075.49.59.192/2675.49.59.193 to 75.49.59.25475.49.59.25562
24175.49.60.0/2675.49.60.1 to 75.49.60.6275.49.60.6362
24275.49.60.64/2675.49.60.65 to 75.49.60.12675.49.60.12762
24375.49.60.128/2675.49.60.129 to 75.49.60.19075.49.60.19162
24475.49.60.192/2675.49.60.193 to 75.49.60.25475.49.60.25562
24575.49.61.0/2675.49.61.1 to 75.49.61.6275.49.61.6362
24675.49.61.64/2675.49.61.65 to 75.49.61.12675.49.61.12762
24775.49.61.128/2675.49.61.129 to 75.49.61.19075.49.61.19162
24875.49.61.192/2675.49.61.193 to 75.49.61.25475.49.61.25562
24975.49.62.0/2675.49.62.1 to 75.49.62.6275.49.62.6362
25075.49.62.64/2675.49.62.65 to 75.49.62.12675.49.62.12762
25175.49.62.128/2675.49.62.129 to 75.49.62.19075.49.62.19162
25275.49.62.192/2675.49.62.193 to 75.49.62.25475.49.62.25562
25375.49.63.0/2675.49.63.1 to 75.49.63.6275.49.63.6362
25475.49.63.64/2675.49.63.65 to 75.49.63.12675.49.63.12762
25575.49.63.128/2675.49.63.129 to 75.49.63.19075.49.63.19162
25675.49.63.192/2675.49.63.193 to 75.49.63.25475.49.63.25562

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.