I am looking for a program that:

  • can copy several files and overwriting only if the size of the file differs from the file that has the same name.
  • works on Windows 7

If possible:

  • GUI
  • free


Folder A:
a.jpg 20KB
b.jpg 5KB
c.jpg 15KB

Folder B:
a.jpg 20KB
b.jpg 2KB

If I copy Folder A to Folder B, I want Folder B to contain the same as folder A at the end of the operation, but I don't want the program to copy a.jpg again (because a.jpg in Folder A has the same size as a.jpg in Folder B).

In other words, just like we can do in FileZilla:

enter image description here

TeraCopy doesn't have this function (can only choose to overwrite is the target folder has the file that is older than the source folder's file):

enter image description here

Copy Handler doesn't seem to have this function either:

enter image description here

  • Is there a reason for selecting the size over the date attribute? I think date is more reliable (replacing a character in a text file won't change the size for example), and you'd be able to use the Windows intrinsic Robocopy command (which has several GUI front-ends)
    – Tymric
    Dec 8, 2014 at 19:22

3 Answers 3


Copying files except when they look identical is what rsync is all about. You can install rsync as part of your favorite collection of Unix tools (I use Cygwin) or one of the various rsync GUIs for Windows. The command line is

rsync --size-only -a "Folder A/" "Folder B/"

(note the slashes at the end, without them rsync would create Folder A as a subdirectory of Folder B). By default (without the --size-only option), rsync skips files if they have the same size and modification time on both sides, which may be ok for you.

Some rsync GUIs are targeted at remote backups and probably won't help you. One that looks appropriate (but I haven't used it, so I can't confirm) is grsync.


You can't not in Windows (in Windows is what you see is what you get) unless you are thinking to use third party solution like CuteFTP files transfer. here is the link for more information. Hope this was helpful



As SolutionSurfers said in one comment, you can use FastCopy:

  • free
  • portable version available
  • Windows XP/Vista/7/8/8.1/10; Windows Server 2003/2008/2012
  • has an option "Diff (Size/date): Copy if size or date is different, or if it doesn't exist (in default)"

enter image description here

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