Windows 10 (64 bit), Emacs 25.1, package dired+.
In dired mode files size show in bytes. But I want to show in KB.
Try using h among your dired-listing-switches - e.g., -alFh. It stands for "human-readable", and it shows sizes in KB etc.
But which ls switches are available can depend on your particular ls command (e.g. on your platform), so try M-x man RET ls RET.
Instead of, or in addition to, setting dired-listing-switches, you can just use a prefix arg with command dired, to be prompted for the ls switches to use for that directory listing. E.g., C-u C-x d.
Update 2019-06-16. If your ls supports it (or if you use built-in ls-lisp.el, which is the case by default for MS Windows) you can use S (uppercase) with h to show and sort by human-readable size.
Does dired-listing-switches help? I've set mine to -alh and I get the filesizes in KB, but not the available bytes. There might be another setting for that.
