# Reading 2021-08-14

## Metadata

- Ref:: Interactive Mathematics
- Title:: Rule of 72
- Author::
- Year of publication:: 2018
- Category::
- Topic:: #topic.investment

## Notes from reading

Here is a graph showing $1 doubling at different interest rates.

This is a trick that allows us to mentally estimate annual compound interest amounts, where we are interested in doubling our money

If we want to know how long it will take for our money to double, just divide 72 by the interest rate

So for example, if the interest rate is 10%,

72 รท 10 = 7.2 years

So it will take just over 7 years to double our money