There is an example of Bat file which can give output of file size in human readable format (Value with KB / MB etc ). This bat file is good with some copying / backup bat files. Here you will get the file size in variable called %size% . You can test the script by giving and input variable for %file%.

echo off
set /p file= Type your file name :
for /f "tokens=4 " %%a in ('dir /a-d/-c %file% ^| findstr /e %file%') do set size=%%a
set /a KB=(%size%/1024)
echo %KB% KB
set /a MB=(%size%/1024)/1024
Echo %MB% MB
pause