Percentage is a hundredth of a number. Using it, you can calculate the proportion of any size. Simple interest is the amount that is calculated at the end of the billing period for the original loan provided. It is most often used to calculate the accumulated amount of issued investments or loans. Banking money should “work” and bring income to the lender. When issuing a loan, interest arises - it is the cost, calculated mathematically, which will be earned from the provision of a loan. If income is calculated only on the amount issued, this is called a simple percentage. You can calculate it by having three indicators:
- The amount of funds taken on credit or invested.
- Interest rate - the rate necessary to calculate the amount of interest. It is contractual between the lender and the borrower. It is expressed as a percentage in the form of an ordinary fraction or decimal.
- Time period - the period during which it is necessary to pay off the debt.
The longer the period for which the loan is given, the greater the interest of the lender. The standard time interval in financial transactions is most often considered a calendar year. Therefore, a simple percentage is calculated after this period for the amount received once depending on the interest rate.
This scheme assumes that the base on which the accrual takes place will be unchanged. Let the loan (or investment) taken be equal to P, the interest rate - r. Money is borrowed on the condition of simple interest, if the creditor’s capital is increased annually by Pr. And after n years, he will be able to get the sum Sn: Sn = P + Pr + ... + Pr = P (1 + nr).
In other words, if you take the amount of money in the bank in the amount of 10 thousand rubles at a simple percentage, for example 10%, then after a year you need to give 11 thousand rubles.
Sn = 10000 + 10000 x 10% = 11000 rub.
In two years this amount will be 12 thousand rubles, and in three years - 13 thousand rubles.
Since the formula consists of four variables, four types of problems can be solved. The first is the direct location of the accrued number and three reverse locations: the amount of invested funds, interest rate and the time of lending. This calculation is correct if the loan time is equal to a year. Then from this formula it follows that the interest rate is:
r = S / P - 1 / n.
If we need to calculate simple interest in months, the formula will have a different look. Let the time span be given 3 months, then r = S / P - 1:
R3 / 12 = P + Pr / (12 x 3).
Calculating a percentage of the amount for a certain period is easy using the simple interest formula. For simplicity of calculations, we convert the rate to a decimal fraction. For this, its value is divided by 100 (r / 100).
Bank agreements indicate the interest rate, which is set for a period of one year. With its help, you can determine the amount of income. If this value is divided by the number of days in a year, then you can determine the amount of interest per day. The amount of daily interest multiplied by the required period will give us income for this billing period.
For example, the amount of the initial loan S - 200 thousand rubles. Interest rate - 14.5%. The billing period is one month (or 31 days). Task: calculate the necessary amount that you need to pay for the loan. Decision:
200 x 14.5 / 100 x 31/365 = 2,463 thousand rubles.