Zend certified PHP/Magento developer

File size discrepancy in Windows Explorer

I need to calculate some file sizes and while looking at the properties in Explorer there seems to be a discrepancy in the displayed values. One value is presented when I hover the cursor over the file, and the other is displayed in Explorer file attributes field:

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Then there is always the discrepancy that is displayed in the file properties window:

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My question is twofold:

  • which file size that is displayed in Explorer is the real file size?
  • why are these file sizes showing different values?

Running Windows 10 Pro