Interest rate is the amount a lender charges for the use of assets expressed as a percentage of the principal. It is typically noted on an annual basis known as the APR.
Compound interest to calculate by using the multiplier method. For example, a 4% increase on the original balance (principal) in a savings account.
In maths, using multipliers is a more efficient method for calculating a percentage increase (for saving or investment) or decrease (depreciation of an asset or a financing credit).
The money supply multiplier is also another variation of a standard-multiplier that’s using the value (spend or saving) to analyze effects on the money-supply.
Your credit card compound interest the term charge at your principal (credit-balance) and then multiply that your balance with apr.