Why the size of the .hex file generated from seggerIDE and armgcc compiler diffrent?

[RitD]

I have provided the starting address and the size of the flash and ram in the linker script of the gccarm compiler, yet the sizes of the output hex file is different, could you please help me with compiling the same project using ARMGCC . 

[Vidar Berg]

The FW sizes for the two builds should be fairly close as long as you use the same optimization settings, but I would not expect them to be identical. For that you would have to use the same GCC version and same implementation of the standard C libraries (SES C library).