Formula to find the flat rate interest

Flat rate interest formula is given by:

Flat interest = Principal amount x Interest rate x Time period

Where:
- Principal amount is the initial amount of money borrowed or invested
- Interest rate is the percentage of the principal amount that is charged as interest for a specified period
- Time period is the amount of time the money is borrowed or invested for.

For example, if you borrow $1,000 at a flat interest rate of 5% for 1 year, then the calculation would be:
Flat interest = $1,000 x 0.05 x 1
Flat interest = $50

So, you will have to pay $50 as flat interest on the $1,000 loan for 1 year.