Simple Interest 365 days per year Annual Period: From days To Principle % Rate Interest Total

Exponential Growth F = S*r^t

Compound interest     Show: prior totals all rows % Annual Interest Rate Years Periods           Periods per year (0= cont.) Starting Balance / Present Value Periodic payment at end Final Balance / Future Value   Year / Period     Initial   Amount       Payment         Interest         New   Balance

Financial calculations can involve simple interest or compound interest. The simple interest formula is: I= Prt, where P= the principle, r is the interest rate per period and t is the number of periods. With compound interest the interest is added to the principle and included in the interest calculation for the next period. An annuity also adds or subtracts a fixed amount from the principle. An ordinary annuity (annuity in arrears) adds the amount at the end of the period. An annuity due (annuity In advance) adds the amount at the beginning of the period. Mortgages are examples of an ordinary annuity. Variables that are usually used for these calculations are: S= Principle, Present Value, or Starting Amount P= Periodic Payment Amount F= Future or Final Amount m= number of periods per year, t= number of years, n= Total number of periods = t*m i= annual interest rate (APR), r= Interest per period = i/m You can calculate any of these values from the others by using formulas like these: F= S * (1+r)^n + P * ((1+r)^n-1) / r S= (F + (P * ((1+r)^n-1) / r))/(1+r)^n P= r*(S(1+r)^n - F)/(1-(1+r)^n) n= [ ln ((r*F+P)/(r*S+P))/ln(1+r)]