The simple interest calculator helps to estimate the interest amount using principal amount, annual interest rate, and investment time.

- Enter the principal amount, annual interest rate, and investment time (in days, weeks, months, quarters, or years).
- After entering all the values, click the 'Calculate' button.
- As a result, the tool returns the interest earned and the total amount (including interest).

The simple interest is calculated using the following formula.

A = P(1 + rt)

Where,

A = Final amount (principal + interest)

P = Principal amount

r = Annual interest rate (decimal)

t = Time (in years)

Let's take an example.

A person invested $2300 at the annual interest rate of 5.6% for 3 years. Find out the interest amount.

Here,

P = $2300,

r = 5.6% = 5.6/100 = 0.056 (in decimal),

t = 3 (years).

Put all the values in the formula.

**A = P(1 + rt)**

= 2300 × (1 + (0.056 × 3))

= 2300 × (1 + 0.168)

= 2300 × 1.168

= 2686.4

Interest Earned = **$2686.4 - $2300 = $386.4**.

So, after 3 years, you will earn interest of $386.4 and the invested amount will become $2686.4.