Convert-BytesToHumanReadable.ps1

<#
.SUMMARY
    Converts bytes values into human readable forms.

.DESCRIPTION
    Converts bytes values into human readable forms.

.PARAMETER Bytes
    Input in Bytes

.PARAMETER KB
    Input in Kilobytes

.PARAMETER MB
    Input in Megabytes

.PARAMETER GB
    Input in Gigabytes

.PARAMETER TB
    Input in Terabytes

.PARAMETER PB
    Input in Petabytes
#>
[CmdletBinding(DefaultParameterSetName='Bytes')]
param(
        
    [Parameter(Mandatory, ParameterSetName='Bytes')]
    [int64]
    $Bytes,

    [Parameter(Mandatory, ParameterSetName='KB')]
    [int64]
    $KB,

    [Parameter(Mandatory, ParameterSetName='MB')]
    [int64]
    $MB,

    [Parameter(Mandatory, ParameterSetName='GB')]
    [int64]
    $GB,

    [Parameter(Mandatory, ParameterSetName='TB')]
    [int64]
    $TB,

    [Parameter(Mandatory, ParameterSetName='PB')]
    [int64]
    $PB

)

switch ( $PSCmdlet.ParameterSetName ) {
    'KB' { $Bytes = $KB * 1024 }
    'MB' { $Bytes = $MB * 1048576 }
    'GB' { $Bytes = $GB * 1073741824 }
    'TB' { $Bytes = $TB * 1099511627776 }
    'PB' { $Bytes = $PB * 1125899906842624 }
}

switch ( $Bytes ) {
    {$Bytes -ge 1PB} { return '{0:N1} PB' -f ($Bytes / 1PB) }
    {$Bytes -ge 1TB} { return '{0:N1} TB' -f ($Bytes / 1TB) }
    {$Bytes -ge 1GB} { return '{0:N1} GB' -f ($Bytes / 1GB) }
    {$Bytes -ge 1MB} { return '{0:N1} MB' -f ($Bytes / 1MB) }
    {$Bytes -ge 1KB} { return '{0:N1} KB' -f ($Bytes / 1KB) }
    default          { return '{0:N1} B ' -f  $Bytes        }
}