Slash notation lookup table

Total-addresses: how many unique addresses can be represented. To determine how many are available to be assigned to devices you need to subtract 2 from the provided number to allow for the ‘network’ and ‘broadcast’ address. A further one of these may need to be assigned to a router.

Net bits Subnet mask Total-addresses
/20 4096
/21 2048
/22 1024
/23 512
/24 256
/25 128
/26 64
/27 32
/28 16
/29 8
/30 4

eg: would include all address between and

eg: would include all address between and

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