Exponential growth occurs whenever the growth depends on the current situation.

Let’s take a population of rabbits.
The number of rabbits in the next generation depends on the number of currently existing rabbits.

Or let’s take economic growth.
If the economic growth rate of a country is 3%, this means that the growth is 3% of the GDP of the previous year.
If you take a country with a large economy, 3% results in higher growth than in a country with a smaller economy.

Or we can take the spread of an infectious disease.
The number of people who are going to be infected next depends on the number of people who are currently infected.

Now, let’s have a look at how to quantify exponential growth.
Let’s look at the rabbit example again. The number of rabbits in the next generation depends on how many children a rabbit can give birth to.

The number of children that a rabbit can give birth to is the base of the exponential growth.
The base, along with the number of currently existing rabbits, fully determines the number of rabbits in each generation.

  • What is the base of the rabbit population growth if every rabbit has 5 children?
    → Somehow 5.

  • What is the base of economic growth?
    → Somehow 3%