Compiled sketch vs text file size
The size of the text file and the size of your compiled code are impossible to relate. The compiled size purely depends on what your code consists of, not the size.

To find out how much room your code will take on the chip you need to compile it. The IDE will then tell you how much flash and RAM it takes.

For example:

Sketch uses 3730 bytes (13%) of program storage space. Maximum is 28672 bytes.
Global variables use 157 bytes (6%) of dynamic memory, leaving 2403 bytes for local variables. Maximum is 2560 bytes.