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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.

Network75.0.0.0/9
Usable hosts8,388,606
Subnet mask255.128.0.0
Addresses8,388,608
Network address
75.0.0.0
Broadcast address
75.127.255.255
First usable
75.0.0.1
Last usable
75.127.255.254
Usable hosts
8,388,606 (8,388,608 less the network and broadcast addresses)
Subnet mask
255.128.0.0
Wildcard mask
0.127.255.255 (Cisco ACLs, OSPF)
Prefix length
/9
Type
Public public
Old class
A (default /8)
As numbers
Hex 4B000000 · Integer 1258291200 to 1266679807
Reverse DNS zones
0.75.in-addr.arpa
1.75.in-addr.arpa
2.75.in-addr.arpa
3.75.in-addr.arpa
4.75.in-addr.arpa
5.75.in-addr.arpa
6.75.in-addr.arpa
7.75.in-addr.arpa
8.75.in-addr.arpa
9.75.in-addr.arpa
10.75.in-addr.arpa
11.75.in-addr.arpa
12.75.in-addr.arpa
13.75.in-addr.arpa
14.75.in-addr.arpa
15.75.in-addr.arpa
and 112 more
/9 is not on a 8-bit boundary, so it takes 128 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01001011.00000000.00000000.0000000075.0.0.0
Subnet mask11111111.10000000.00000000.00000000255.128.0.0
Network01001011.00000000.00000000.0000000075.0.0.0
Broadcast01001011.01111111.11111111.1111111175.127.255.255
Split into smaller subnets/19
/10 (2)/11 (4)/12 (8)/13 (16)/14 (32)/15 (64)/16 (128)/17 (256)/18 (512)/19 (1,024)/20 (2,048)/21 (4,096)

75.0.0.0/9 makes 1,024 subnets of /19; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
175.0.0.0/1975.0.0.1 to 75.0.31.25475.0.31.2558,190
275.0.32.0/1975.0.32.1 to 75.0.63.25475.0.63.2558,190
375.0.64.0/1975.0.64.1 to 75.0.95.25475.0.95.2558,190
475.0.96.0/1975.0.96.1 to 75.0.127.25475.0.127.2558,190
575.0.128.0/1975.0.128.1 to 75.0.159.25475.0.159.2558,190
675.0.160.0/1975.0.160.1 to 75.0.191.25475.0.191.2558,190
775.0.192.0/1975.0.192.1 to 75.0.223.25475.0.223.2558,190
875.0.224.0/1975.0.224.1 to 75.0.255.25475.0.255.2558,190
975.1.0.0/1975.1.0.1 to 75.1.31.25475.1.31.2558,190
1075.1.32.0/1975.1.32.1 to 75.1.63.25475.1.63.2558,190
1175.1.64.0/1975.1.64.1 to 75.1.95.25475.1.95.2558,190
1275.1.96.0/1975.1.96.1 to 75.1.127.25475.1.127.2558,190
1375.1.128.0/1975.1.128.1 to 75.1.159.25475.1.159.2558,190
1475.1.160.0/1975.1.160.1 to 75.1.191.25475.1.191.2558,190
1575.1.192.0/1975.1.192.1 to 75.1.223.25475.1.223.2558,190
1675.1.224.0/1975.1.224.1 to 75.1.255.25475.1.255.2558,190
1775.2.0.0/1975.2.0.1 to 75.2.31.25475.2.31.2558,190
1875.2.32.0/1975.2.32.1 to 75.2.63.25475.2.63.2558,190
1975.2.64.0/1975.2.64.1 to 75.2.95.25475.2.95.2558,190
2075.2.96.0/1975.2.96.1 to 75.2.127.25475.2.127.2558,190
2175.2.128.0/1975.2.128.1 to 75.2.159.25475.2.159.2558,190
2275.2.160.0/1975.2.160.1 to 75.2.191.25475.2.191.2558,190
2375.2.192.0/1975.2.192.1 to 75.2.223.25475.2.223.2558,190
2475.2.224.0/1975.2.224.1 to 75.2.255.25475.2.255.2558,190
2575.3.0.0/1975.3.0.1 to 75.3.31.25475.3.31.2558,190
2675.3.32.0/1975.3.32.1 to 75.3.63.25475.3.63.2558,190
2775.3.64.0/1975.3.64.1 to 75.3.95.25475.3.95.2558,190
2875.3.96.0/1975.3.96.1 to 75.3.127.25475.3.127.2558,190
2975.3.128.0/1975.3.128.1 to 75.3.159.25475.3.159.2558,190
3075.3.160.0/1975.3.160.1 to 75.3.191.25475.3.191.2558,190
3175.3.192.0/1975.3.192.1 to 75.3.223.25475.3.223.2558,190
3275.3.224.0/1975.3.224.1 to 75.3.255.25475.3.255.2558,190
3375.4.0.0/1975.4.0.1 to 75.4.31.25475.4.31.2558,190
3475.4.32.0/1975.4.32.1 to 75.4.63.25475.4.63.2558,190
3575.4.64.0/1975.4.64.1 to 75.4.95.25475.4.95.2558,190
3675.4.96.0/1975.4.96.1 to 75.4.127.25475.4.127.2558,190
3775.4.128.0/1975.4.128.1 to 75.4.159.25475.4.159.2558,190
3875.4.160.0/1975.4.160.1 to 75.4.191.25475.4.191.2558,190
3975.4.192.0/1975.4.192.1 to 75.4.223.25475.4.223.2558,190
4075.4.224.0/1975.4.224.1 to 75.4.255.25475.4.255.2558,190
4175.5.0.0/1975.5.0.1 to 75.5.31.25475.5.31.2558,190
4275.5.32.0/1975.5.32.1 to 75.5.63.25475.5.63.2558,190
4375.5.64.0/1975.5.64.1 to 75.5.95.25475.5.95.2558,190
4475.5.96.0/1975.5.96.1 to 75.5.127.25475.5.127.2558,190
4575.5.128.0/1975.5.128.1 to 75.5.159.25475.5.159.2558,190
4675.5.160.0/1975.5.160.1 to 75.5.191.25475.5.191.2558,190
4775.5.192.0/1975.5.192.1 to 75.5.223.25475.5.223.2558,190
4875.5.224.0/1975.5.224.1 to 75.5.255.25475.5.255.2558,190
4975.6.0.0/1975.6.0.1 to 75.6.31.25475.6.31.2558,190
5075.6.32.0/1975.6.32.1 to 75.6.63.25475.6.63.2558,190
5175.6.64.0/1975.6.64.1 to 75.6.95.25475.6.95.2558,190
5275.6.96.0/1975.6.96.1 to 75.6.127.25475.6.127.2558,190
5375.6.128.0/1975.6.128.1 to 75.6.159.25475.6.159.2558,190
5475.6.160.0/1975.6.160.1 to 75.6.191.25475.6.191.2558,190
5575.6.192.0/1975.6.192.1 to 75.6.223.25475.6.223.2558,190
5675.6.224.0/1975.6.224.1 to 75.6.255.25475.6.255.2558,190
5775.7.0.0/1975.7.0.1 to 75.7.31.25475.7.31.2558,190
5875.7.32.0/1975.7.32.1 to 75.7.63.25475.7.63.2558,190
5975.7.64.0/1975.7.64.1 to 75.7.95.25475.7.95.2558,190
6075.7.96.0/1975.7.96.1 to 75.7.127.25475.7.127.2558,190
6175.7.128.0/1975.7.128.1 to 75.7.159.25475.7.159.2558,190
6275.7.160.0/1975.7.160.1 to 75.7.191.25475.7.191.2558,190
6375.7.192.0/1975.7.192.1 to 75.7.223.25475.7.223.2558,190
6475.7.224.0/1975.7.224.1 to 75.7.255.25475.7.255.2558,190
6575.8.0.0/1975.8.0.1 to 75.8.31.25475.8.31.2558,190
6675.8.32.0/1975.8.32.1 to 75.8.63.25475.8.63.2558,190
6775.8.64.0/1975.8.64.1 to 75.8.95.25475.8.95.2558,190
6875.8.96.0/1975.8.96.1 to 75.8.127.25475.8.127.2558,190
6975.8.128.0/1975.8.128.1 to 75.8.159.25475.8.159.2558,190
7075.8.160.0/1975.8.160.1 to 75.8.191.25475.8.191.2558,190
7175.8.192.0/1975.8.192.1 to 75.8.223.25475.8.223.2558,190
7275.8.224.0/1975.8.224.1 to 75.8.255.25475.8.255.2558,190
7375.9.0.0/1975.9.0.1 to 75.9.31.25475.9.31.2558,190
7475.9.32.0/1975.9.32.1 to 75.9.63.25475.9.63.2558,190
7575.9.64.0/1975.9.64.1 to 75.9.95.25475.9.95.2558,190
7675.9.96.0/1975.9.96.1 to 75.9.127.25475.9.127.2558,190
7775.9.128.0/1975.9.128.1 to 75.9.159.25475.9.159.2558,190
7875.9.160.0/1975.9.160.1 to 75.9.191.25475.9.191.2558,190
7975.9.192.0/1975.9.192.1 to 75.9.223.25475.9.223.2558,190
8075.9.224.0/1975.9.224.1 to 75.9.255.25475.9.255.2558,190
8175.10.0.0/1975.10.0.1 to 75.10.31.25475.10.31.2558,190
8275.10.32.0/1975.10.32.1 to 75.10.63.25475.10.63.2558,190
8375.10.64.0/1975.10.64.1 to 75.10.95.25475.10.95.2558,190
8475.10.96.0/1975.10.96.1 to 75.10.127.25475.10.127.2558,190
8575.10.128.0/1975.10.128.1 to 75.10.159.25475.10.159.2558,190
8675.10.160.0/1975.10.160.1 to 75.10.191.25475.10.191.2558,190
8775.10.192.0/1975.10.192.1 to 75.10.223.25475.10.223.2558,190
8875.10.224.0/1975.10.224.1 to 75.10.255.25475.10.255.2558,190
8975.11.0.0/1975.11.0.1 to 75.11.31.25475.11.31.2558,190
9075.11.32.0/1975.11.32.1 to 75.11.63.25475.11.63.2558,190
9175.11.64.0/1975.11.64.1 to 75.11.95.25475.11.95.2558,190
9275.11.96.0/1975.11.96.1 to 75.11.127.25475.11.127.2558,190
9375.11.128.0/1975.11.128.1 to 75.11.159.25475.11.159.2558,190
9475.11.160.0/1975.11.160.1 to 75.11.191.25475.11.191.2558,190
9575.11.192.0/1975.11.192.1 to 75.11.223.25475.11.223.2558,190
9675.11.224.0/1975.11.224.1 to 75.11.255.25475.11.255.2558,190
9775.12.0.0/1975.12.0.1 to 75.12.31.25475.12.31.2558,190
9875.12.32.0/1975.12.32.1 to 75.12.63.25475.12.63.2558,190
9975.12.64.0/1975.12.64.1 to 75.12.95.25475.12.95.2558,190
10075.12.96.0/1975.12.96.1 to 75.12.127.25475.12.127.2558,190
10175.12.128.0/1975.12.128.1 to 75.12.159.25475.12.159.2558,190
10275.12.160.0/1975.12.160.1 to 75.12.191.25475.12.191.2558,190
10375.12.192.0/1975.12.192.1 to 75.12.223.25475.12.223.2558,190
10475.12.224.0/1975.12.224.1 to 75.12.255.25475.12.255.2558,190
10575.13.0.0/1975.13.0.1 to 75.13.31.25475.13.31.2558,190
10675.13.32.0/1975.13.32.1 to 75.13.63.25475.13.63.2558,190
10775.13.64.0/1975.13.64.1 to 75.13.95.25475.13.95.2558,190
10875.13.96.0/1975.13.96.1 to 75.13.127.25475.13.127.2558,190
10975.13.128.0/1975.13.128.1 to 75.13.159.25475.13.159.2558,190
11075.13.160.0/1975.13.160.1 to 75.13.191.25475.13.191.2558,190
11175.13.192.0/1975.13.192.1 to 75.13.223.25475.13.223.2558,190
11275.13.224.0/1975.13.224.1 to 75.13.255.25475.13.255.2558,190
11375.14.0.0/1975.14.0.1 to 75.14.31.25475.14.31.2558,190
11475.14.32.0/1975.14.32.1 to 75.14.63.25475.14.63.2558,190
11575.14.64.0/1975.14.64.1 to 75.14.95.25475.14.95.2558,190
11675.14.96.0/1975.14.96.1 to 75.14.127.25475.14.127.2558,190
11775.14.128.0/1975.14.128.1 to 75.14.159.25475.14.159.2558,190
11875.14.160.0/1975.14.160.1 to 75.14.191.25475.14.191.2558,190
11975.14.192.0/1975.14.192.1 to 75.14.223.25475.14.223.2558,190
12075.14.224.0/1975.14.224.1 to 75.14.255.25475.14.255.2558,190
12175.15.0.0/1975.15.0.1 to 75.15.31.25475.15.31.2558,190
12275.15.32.0/1975.15.32.1 to 75.15.63.25475.15.63.2558,190
12375.15.64.0/1975.15.64.1 to 75.15.95.25475.15.95.2558,190
12475.15.96.0/1975.15.96.1 to 75.15.127.25475.15.127.2558,190
12575.15.128.0/1975.15.128.1 to 75.15.159.25475.15.159.2558,190
12675.15.160.0/1975.15.160.1 to 75.15.191.25475.15.191.2558,190
12775.15.192.0/1975.15.192.1 to 75.15.223.25475.15.223.2558,190
12875.15.224.0/1975.15.224.1 to 75.15.255.25475.15.255.2558,190
12975.16.0.0/1975.16.0.1 to 75.16.31.25475.16.31.2558,190
13075.16.32.0/1975.16.32.1 to 75.16.63.25475.16.63.2558,190
13175.16.64.0/1975.16.64.1 to 75.16.95.25475.16.95.2558,190
13275.16.96.0/1975.16.96.1 to 75.16.127.25475.16.127.2558,190
13375.16.128.0/1975.16.128.1 to 75.16.159.25475.16.159.2558,190
13475.16.160.0/1975.16.160.1 to 75.16.191.25475.16.191.2558,190
13575.16.192.0/1975.16.192.1 to 75.16.223.25475.16.223.2558,190
13675.16.224.0/1975.16.224.1 to 75.16.255.25475.16.255.2558,190
13775.17.0.0/1975.17.0.1 to 75.17.31.25475.17.31.2558,190
13875.17.32.0/1975.17.32.1 to 75.17.63.25475.17.63.2558,190
13975.17.64.0/1975.17.64.1 to 75.17.95.25475.17.95.2558,190
14075.17.96.0/1975.17.96.1 to 75.17.127.25475.17.127.2558,190
14175.17.128.0/1975.17.128.1 to 75.17.159.25475.17.159.2558,190
14275.17.160.0/1975.17.160.1 to 75.17.191.25475.17.191.2558,190
14375.17.192.0/1975.17.192.1 to 75.17.223.25475.17.223.2558,190
14475.17.224.0/1975.17.224.1 to 75.17.255.25475.17.255.2558,190
14575.18.0.0/1975.18.0.1 to 75.18.31.25475.18.31.2558,190
14675.18.32.0/1975.18.32.1 to 75.18.63.25475.18.63.2558,190
14775.18.64.0/1975.18.64.1 to 75.18.95.25475.18.95.2558,190
14875.18.96.0/1975.18.96.1 to 75.18.127.25475.18.127.2558,190
14975.18.128.0/1975.18.128.1 to 75.18.159.25475.18.159.2558,190
15075.18.160.0/1975.18.160.1 to 75.18.191.25475.18.191.2558,190
15175.18.192.0/1975.18.192.1 to 75.18.223.25475.18.223.2558,190
15275.18.224.0/1975.18.224.1 to 75.18.255.25475.18.255.2558,190
15375.19.0.0/1975.19.0.1 to 75.19.31.25475.19.31.2558,190
15475.19.32.0/1975.19.32.1 to 75.19.63.25475.19.63.2558,190
15575.19.64.0/1975.19.64.1 to 75.19.95.25475.19.95.2558,190
15675.19.96.0/1975.19.96.1 to 75.19.127.25475.19.127.2558,190
15775.19.128.0/1975.19.128.1 to 75.19.159.25475.19.159.2558,190
15875.19.160.0/1975.19.160.1 to 75.19.191.25475.19.191.2558,190
15975.19.192.0/1975.19.192.1 to 75.19.223.25475.19.223.2558,190
16075.19.224.0/1975.19.224.1 to 75.19.255.25475.19.255.2558,190
16175.20.0.0/1975.20.0.1 to 75.20.31.25475.20.31.2558,190
16275.20.32.0/1975.20.32.1 to 75.20.63.25475.20.63.2558,190
16375.20.64.0/1975.20.64.1 to 75.20.95.25475.20.95.2558,190
16475.20.96.0/1975.20.96.1 to 75.20.127.25475.20.127.2558,190
16575.20.128.0/1975.20.128.1 to 75.20.159.25475.20.159.2558,190
16675.20.160.0/1975.20.160.1 to 75.20.191.25475.20.191.2558,190
16775.20.192.0/1975.20.192.1 to 75.20.223.25475.20.223.2558,190
16875.20.224.0/1975.20.224.1 to 75.20.255.25475.20.255.2558,190
16975.21.0.0/1975.21.0.1 to 75.21.31.25475.21.31.2558,190
17075.21.32.0/1975.21.32.1 to 75.21.63.25475.21.63.2558,190
17175.21.64.0/1975.21.64.1 to 75.21.95.25475.21.95.2558,190
17275.21.96.0/1975.21.96.1 to 75.21.127.25475.21.127.2558,190
17375.21.128.0/1975.21.128.1 to 75.21.159.25475.21.159.2558,190
17475.21.160.0/1975.21.160.1 to 75.21.191.25475.21.191.2558,190
17575.21.192.0/1975.21.192.1 to 75.21.223.25475.21.223.2558,190
17675.21.224.0/1975.21.224.1 to 75.21.255.25475.21.255.2558,190
17775.22.0.0/1975.22.0.1 to 75.22.31.25475.22.31.2558,190
17875.22.32.0/1975.22.32.1 to 75.22.63.25475.22.63.2558,190
17975.22.64.0/1975.22.64.1 to 75.22.95.25475.22.95.2558,190
18075.22.96.0/1975.22.96.1 to 75.22.127.25475.22.127.2558,190
18175.22.128.0/1975.22.128.1 to 75.22.159.25475.22.159.2558,190
18275.22.160.0/1975.22.160.1 to 75.22.191.25475.22.191.2558,190
18375.22.192.0/1975.22.192.1 to 75.22.223.25475.22.223.2558,190
18475.22.224.0/1975.22.224.1 to 75.22.255.25475.22.255.2558,190
18575.23.0.0/1975.23.0.1 to 75.23.31.25475.23.31.2558,190
18675.23.32.0/1975.23.32.1 to 75.23.63.25475.23.63.2558,190
18775.23.64.0/1975.23.64.1 to 75.23.95.25475.23.95.2558,190
18875.23.96.0/1975.23.96.1 to 75.23.127.25475.23.127.2558,190
18975.23.128.0/1975.23.128.1 to 75.23.159.25475.23.159.2558,190
19075.23.160.0/1975.23.160.1 to 75.23.191.25475.23.191.2558,190
19175.23.192.0/1975.23.192.1 to 75.23.223.25475.23.223.2558,190
19275.23.224.0/1975.23.224.1 to 75.23.255.25475.23.255.2558,190
19375.24.0.0/1975.24.0.1 to 75.24.31.25475.24.31.2558,190
19475.24.32.0/1975.24.32.1 to 75.24.63.25475.24.63.2558,190
19575.24.64.0/1975.24.64.1 to 75.24.95.25475.24.95.2558,190
19675.24.96.0/1975.24.96.1 to 75.24.127.25475.24.127.2558,190
19775.24.128.0/1975.24.128.1 to 75.24.159.25475.24.159.2558,190
19875.24.160.0/1975.24.160.1 to 75.24.191.25475.24.191.2558,190
19975.24.192.0/1975.24.192.1 to 75.24.223.25475.24.223.2558,190
20075.24.224.0/1975.24.224.1 to 75.24.255.25475.24.255.2558,190
20175.25.0.0/1975.25.0.1 to 75.25.31.25475.25.31.2558,190
20275.25.32.0/1975.25.32.1 to 75.25.63.25475.25.63.2558,190
20375.25.64.0/1975.25.64.1 to 75.25.95.25475.25.95.2558,190
20475.25.96.0/1975.25.96.1 to 75.25.127.25475.25.127.2558,190
20575.25.128.0/1975.25.128.1 to 75.25.159.25475.25.159.2558,190
20675.25.160.0/1975.25.160.1 to 75.25.191.25475.25.191.2558,190
20775.25.192.0/1975.25.192.1 to 75.25.223.25475.25.223.2558,190
20875.25.224.0/1975.25.224.1 to 75.25.255.25475.25.255.2558,190
20975.26.0.0/1975.26.0.1 to 75.26.31.25475.26.31.2558,190
21075.26.32.0/1975.26.32.1 to 75.26.63.25475.26.63.2558,190
21175.26.64.0/1975.26.64.1 to 75.26.95.25475.26.95.2558,190
21275.26.96.0/1975.26.96.1 to 75.26.127.25475.26.127.2558,190
21375.26.128.0/1975.26.128.1 to 75.26.159.25475.26.159.2558,190
21475.26.160.0/1975.26.160.1 to 75.26.191.25475.26.191.2558,190
21575.26.192.0/1975.26.192.1 to 75.26.223.25475.26.223.2558,190
21675.26.224.0/1975.26.224.1 to 75.26.255.25475.26.255.2558,190
21775.27.0.0/1975.27.0.1 to 75.27.31.25475.27.31.2558,190
21875.27.32.0/1975.27.32.1 to 75.27.63.25475.27.63.2558,190
21975.27.64.0/1975.27.64.1 to 75.27.95.25475.27.95.2558,190
22075.27.96.0/1975.27.96.1 to 75.27.127.25475.27.127.2558,190
22175.27.128.0/1975.27.128.1 to 75.27.159.25475.27.159.2558,190
22275.27.160.0/1975.27.160.1 to 75.27.191.25475.27.191.2558,190
22375.27.192.0/1975.27.192.1 to 75.27.223.25475.27.223.2558,190
22475.27.224.0/1975.27.224.1 to 75.27.255.25475.27.255.2558,190
22575.28.0.0/1975.28.0.1 to 75.28.31.25475.28.31.2558,190
22675.28.32.0/1975.28.32.1 to 75.28.63.25475.28.63.2558,190
22775.28.64.0/1975.28.64.1 to 75.28.95.25475.28.95.2558,190
22875.28.96.0/1975.28.96.1 to 75.28.127.25475.28.127.2558,190
22975.28.128.0/1975.28.128.1 to 75.28.159.25475.28.159.2558,190
23075.28.160.0/1975.28.160.1 to 75.28.191.25475.28.191.2558,190
23175.28.192.0/1975.28.192.1 to 75.28.223.25475.28.223.2558,190
23275.28.224.0/1975.28.224.1 to 75.28.255.25475.28.255.2558,190
23375.29.0.0/1975.29.0.1 to 75.29.31.25475.29.31.2558,190
23475.29.32.0/1975.29.32.1 to 75.29.63.25475.29.63.2558,190
23575.29.64.0/1975.29.64.1 to 75.29.95.25475.29.95.2558,190
23675.29.96.0/1975.29.96.1 to 75.29.127.25475.29.127.2558,190
23775.29.128.0/1975.29.128.1 to 75.29.159.25475.29.159.2558,190
23875.29.160.0/1975.29.160.1 to 75.29.191.25475.29.191.2558,190
23975.29.192.0/1975.29.192.1 to 75.29.223.25475.29.223.2558,190
24075.29.224.0/1975.29.224.1 to 75.29.255.25475.29.255.2558,190
24175.30.0.0/1975.30.0.1 to 75.30.31.25475.30.31.2558,190
24275.30.32.0/1975.30.32.1 to 75.30.63.25475.30.63.2558,190
24375.30.64.0/1975.30.64.1 to 75.30.95.25475.30.95.2558,190
24475.30.96.0/1975.30.96.1 to 75.30.127.25475.30.127.2558,190
24575.30.128.0/1975.30.128.1 to 75.30.159.25475.30.159.2558,190
24675.30.160.0/1975.30.160.1 to 75.30.191.25475.30.191.2558,190
24775.30.192.0/1975.30.192.1 to 75.30.223.25475.30.223.2558,190
24875.30.224.0/1975.30.224.1 to 75.30.255.25475.30.255.2558,190
24975.31.0.0/1975.31.0.1 to 75.31.31.25475.31.31.2558,190
25075.31.32.0/1975.31.32.1 to 75.31.63.25475.31.63.2558,190
25175.31.64.0/1975.31.64.1 to 75.31.95.25475.31.95.2558,190
25275.31.96.0/1975.31.96.1 to 75.31.127.25475.31.127.2558,190
25375.31.128.0/1975.31.128.1 to 75.31.159.25475.31.159.2558,190
25475.31.160.0/1975.31.160.1 to 75.31.191.25475.31.191.2558,190
25575.31.192.0/1975.31.192.1 to 75.31.223.25475.31.223.2558,190
25675.31.224.0/1975.31.224.1 to 75.31.255.25475.31.255.2558,190

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.