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Free online simple interest calculator

Simple Interest Calculator

Interest Rate 10.25%
No. of Years

How this Online Simple Interest Calculator works?

This online simple interest calculator calculates an accrued amount that includes principal plus interest.

Simple interest equation

A = P(1 + rt)


A = Total Accrued Amount (principal + interest)

P = Principal Amount

I = Interest Amount

r = Rate of Interest per year in decimal; r = R/100

R = Rate of Interest per year as a percent; R = r * 100

t = Time Period involved in months or years

From the base formula, A = P(1 + rt) derived from A = P + I and since I = Prt then A = P + I becomes A = P + Prt which can be rewritten as A = P(1 + rt)

Simple Interest Equation example

Where: A = P(1 + rt)

P= 10,000

r= 3.875%

t= 5 yrs


First, converting R percent to r a decimal r = R/100 = 3.875%/100 = 0.03875 per year.

Solving our equation:

A = 10000(1 + (0.03875 × 5)) = 11937.5
A = $11,937.50

The total amount accrued, principal plus interest, from simple interest on a principal of $10,000.00 at a rate of 3.875% per year for 5 years is $11,937.50.

Simple Interest Formulas and Calculations:

Use this simple interest calculator to find A, the Final Investment Value, using the simple interest formula: A = P(1 + rt) where P is the Principal amount of money to be invested at an Interest Rate R% per period for t Number of Time Periods. Where r is in decimal form; r=R/100; r and t are in the same units of time.

A = P + I = P + (Prt), and finally A = P(1 + rt)

Calculate Total Amount Accrued (Principal + Interest), solve for A

A = P(1 + rt)

Calculate Principal Amount, solve for P

P = A / (1 + rt)

Calculate rate of interest in decimal, solve for r

r = (1/t)(A/P - 1)

Calculate rate of interest in percent

R = r * 100

Calculate time, solve for t

t = (1/r)(A/P - 1)

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