GIGO (Garbage In, Garbage Out) is a computer science principle that means if you put bad (incorrect, incomplete, or nonsensical) input into a system, you will get bad output from it.
A computer will process whatever data it’s given, whether correct or wrong. It doesn’t “know” if the input makes sense—it just follows the rules or program instructions. So, if the input is garbage, the result will also be garbage.
Example:
- If you give a calculator
2 + apple, it cannot produce a meaningful result. - If you enter wrong data into a payroll system (like typing 5000 hours worked instead of 50), the output (the salary calculation) will also be wrong.
Simply put: Wrong input = Wrong output.