Which calculation is used to determine how long it will take to double an investment?

The correct choice is the Rule of 72, a straightforward formula utilized to estimate the number of years required to double an investment based on a fixed annual rate of return. By dividing 72 by the annual interest rate (expressed as a whole number, not a decimal), you can quickly derive an approximate time frame for your investment to double in value. For example, if the investment earns a return of 6% per year, dividing 72 by 6 indicates it will take roughly 12 years to double.

This rule is particularly popular among investors due to its simplicity and usefulness for making quick mental calculations. It provides an efficient way to evaluate potential investment growth without needing complex mathematical formulas, making it more accessible for casual investors.

Other options listed serve different purposes. The Rule of 114 relates to tripling an investment, while net present value is a method for assessing profitability by calculating the difference between an investment's present value of cash inflows and outflows. Return on investment, on the other hand, measures the gain or loss generated relative to the amount invested, rather than calculating a time frame for doubling the investment.