float should only be used if you need to operate on a lot of floating-point numbers (think in the order of thousands or more) and analysis of the algorithm has shown that the reduced range and accuracy don't pose a problem.

When would you use a float data type?

Floating point numbers should be used for what they were designed for: computations where what you want is a fixed precision, and you only care that your answer is accurate to within a certain tolerance. If you need an exact answer in all cases, you're best using something else.

Should I use float or double?

Float and double

Double is more precise than float and can store 64 bits, double of the number of bits float can store. Double is more precise and for storing large numbers, we prefer double over float. For example, to store the annual salary of the CEO of a company, double will be a more accurate choice.