parseFloat rounding

Question

I have javascript function that automatically adds input fields together, but adding numbers like 1.35 + 1.35 + 1.35 gives me an output of 4.050000000000001, just as an exam

Answer 1

Use toFixed() to round num to 2 decimal digits using the traditional rounding method. It will round 4.050000000000001 to 4.05.

num.toFixed(2);

You might prefer using toPrecision(), which will strip any resulting trailing zeros.

Example:

1.35+1.35+1.35 => 4.050000000000001
(1.35+1.35+1.35).toFixed(2)     => 4.05
(1.35+1.35+1.35).toPrecision(3) => 4.05

// or...
(1.35+1.35+1.35).toFixed(4)     => 4.0500
(1.35+1.35+1.35).toPrecision(4) => 4.05

Reference: JavaScript Number Format - Decimal Precision