You can use Powershell to get the block size of a Windows NTFS volume:

On newer systems:

Get-CimInstance -ClassName Win32_Volume | Select DriveLetter,Label, BlockSize | FT -AutoSize

On older systems, the Get-CimInstance may not be available, in which case you can use the (deprecated) Get-WmiObject:

Get-WmiObject -Class Win32_Volume | Select DriveLetter,Label, BlockSize | FT -AutoSize