[anyoan1]

I'd like to achieve something like that:

KI + KIO3 + HCl -> KI + I2 (+ HCl + KCl + H2O)

Focusing only at KI and KIO3
How can i count how many KI in the reaction need to be to "zeroed" KIO3? (and what amount of I2 be created)
From what amount the more grams of KI i add the more will be left untouched
Suppose we have an unlimited amount of HCl (focusing only on KI and KIO3, I2)

[Borek]

Sounds like a simple stoichiometry - first step is to find out reagents and products, then you need to balance the reaction equation.

For balancing same compound can't be present on both sides of the equation.