# Double Time Formula – Problem Solution with Solved Example

## Double Time Formula

The total time span taken to double quantity or size of a product is called the doubling time. The double time formula is applicable for multiple domains like population growth, finance, compound interest, and many other fields. If you know the constant growth rate then double time can be calculated quickly with the help of double time formula as given in mathematics.

The time is calculated by the dividing the natural logarithms of two or the exponent of growth. Here is the double time formula as given in mathematics –

$\LARGE T_{d}=\frac{\log 2}{\log (1+r)}$

Where,
Td = doubling time
r = content growth rate

The most useful application of double time formula can be seen in calculating the time required to double the investment or interest on bearing account. When you will see carefully, r is constant rate of growth per period. If one wanted to calculated the compounded interest on their invested money that will be added monthly then r will express the monthly rate of growth here. And the annual growth rate can be calculated by dividing the value with 12.

In this situation, the double time formula will always give you the total number of months that it will take to double the amount not the years. Additionally, the rule 72 also work in the same way but the rate of interest is always as a whole number here. This is quite common in financial industries that are designing attractive investment plan frequently or another common example bank investments.