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In computing, executable code or an executable file or executable program, sometimes simply an executable or binary, causes a computer "to perform indicated tasks according to encoded instructions," as opposed to a data file that must be parsed by a program to be meaningful. These instructions are traditionally machine code instructions for a physical CPU. However, in a more general sense, a file containing instructions (such as bytecode) for a software interpreter may also be considered executable; even a scripting language source file may therefore be considered executable in this sense. The exact interpretation depends upon the use; while the term often refers only to machine code files, in the context of protection against computer viruses all files which cause potentially hazardous instruction execution, including scripts, are lumped together for convenience.

Executable code is used to describe sequences of executable instructions that do not necessarily constitute an executable file; for example, sections within a program.

While an executable file can be hand-coded in machine language, it is far more usual to develop software as source code in a high-level language easily understood by humans, or in some cases an assembly language more complex for humans but more closely associated with machine code instructions. The high-level language is compiled into either an executable machine code file or a non-executable machine-code object file of some sort; the equivalent process on assembly language source code is called assembly. Several object files are linked to create the executable. Object files, executable or not, are typically in a container format, such as Executable and Linkable Format (ELF). This structures the generated machine code, for example dividing it into sections such as the .text (executable code), .data (static variables), and .rodata (static constants).

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