What is formula to calculate or …

Calculate compound interest on an investment or savings. Using the compound interest formula, calculate principal plus interest or principal or rate or time. Includes compound interest formulas to find principal, interest rates or final investment value including continuous compounding A = Pe^rt.

Compound Interest Equation

A = P(1 + r/n)^nt

Where:

• A = Accrued Amount (principal + interest)
• P = Principal Amount
• I = Interest Amount
• R = Annual Nominal Interest Rate in percent
• r = Annual Nominal Interest Rate as a decimal
• r = R/100
• t = Time Involved in years, 0.5 years is calculated as 6 months, etc.
• n = number of compounding periods per unit t; at the END of each period

Compound Interest Formulas and Calculations:

• Calculate Accrued Amount (Principal + Interest)
  • A = P(1 + r/n)^nt
• Calculate Principal Amount, solve for P
  • P = A / (1 + r/n)^nt
• Calculate rate of interest in decimal, solve for r
  • r = n[(A/P)^1/nt - 1]
• Calculate rate of interest in percent
  • R = r * 100
• Calculate time, solve for t
  • t = ln(A/P) / n[ln(1 + r/n)], then also
  • t = [ ln(A) - ln(P) ] / n[ln(1 + r/n)]

Formulas where n = 1 (compounded once per period or unit t)

• 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
  • R = r * 100
• Calculate time, solve for t
  • t = ln(A/P) / ln(1 + r), then also
  • t = [ ln(A) - ln(P) ] / ln(1 + r)