Sometimes when uploading files to WeTransfer, the file size appears to be smaller than it is on your computer. As we learned as children, however, things are not always as they seem!
The truth is, WeTransfer uses lossless compression, and the size of your transferred files never decreases or diminishes. Instead, the difference between sizes as you see them are due to the “size on disk” being bigger than the actual file size.
To put it simply: the “size on disk” is how much room the file is taking on your computer, not the true size of the file itself. When you upload to WeTransfer, we show the true file size, and it can occasionally appear smaller than the “size on disk.”
You may also see that your file's size has been rounded up or down during an upload or download. We're not sneakily adding in a little bit more to your transfer, or shaving some data off - we're just displaying the closest whole number to keep everything neat and tidy for you.
Rest assured that this smaller size is indeed the actual file size, and your files are just as beautifully uncompressed as ever.