Simple interest refers to the amount of money in a savings account that is obtained by multiplying the principal or capital amount in an account times the rate of interest in a given time period. For example, if you have $10 in a savings account and there is a 10% interest rate per year, you will earn $1 in that same year. 10% of your principal or capital amount is considered to be simple interest.
Simple interest is the concept that when you borrow an amount of money at a given rate, you pay back the principal and any interest charges in full on the date of expiration of your loan. The difference between simple interest and compound interest is that with compound interest, you would get charged the same rate on your original principal and your accrued interest.