Calculate Accrued Amount (Principal + Interest) A = P(1 + r)t
Calculate Principal Amount, solve for P. P = A / (1 + r)t
Calculate rate of interest in decimal, solve for r. r = (A/P)1/t - 1.
Calculate rate of interest in percent. ...
Calculate time, solve for t.
If an amount of $5,000 is deposited into a savings account at an annual interest rate of 5%, compounded monthly, the value of the investment after 10 years can be calculated as follows... P = 5000. r = 5/100 = 0.05 (decimal).