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Compound Interest. Present and Future Values. Wayne Foss, MBA, MAI, CRE, Fullerton, CA USA Email: waynefoss@usa.net. Future Value of One. Also known as the FW of 1 Formula: S n = (1 + i) n Where: S n = Future Factor i = effective rate of interest
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Compound Interest Present and Future Values Wayne Foss, MBA, MAI, CRE, Fullerton, CA USA Email: waynefoss@usa.net
Future Value of One • Also known as the FW of 1 • Formula: Sn = (1 + i)n • Where: Sn = Future Factor i = effective rate of interest n = number of compounding periods
Future Value of OneAn Example Original Investment $1.00 Nominal Interest Rate 10.0% Holding Period in Years 5 Assumes Annual Compounding Dollar Factor Original Investment $1.00 1.0000 Year One interest $0.10 Accumulation end of year 1 $1.10 1.1000 Year Two interest $0.11 Accumulation end of year 2 $1.21 1.2100 Year Three interest $0.12 Accumulation end of year 3 $1.33 1.3310 Year Four interest $0.13 Accumulation end of year 4 $1.46 1.4641 Year Five interest $0.15 Accumulation end of year 5 $1.61 1.61051
Future Value of One per Period • Also known as the FW of 1/Pd • The total accumulation of principal and interest of a series of deposits. • Formula: Sn = (Sn - 1)/i • Where: Sn = Future Factor i = effective rate of interest n = number of compounding periods
Sinking Fund Factor • The level periodic payment or investment required to accumulate one in a given number of periods including the accumulation of interest. • Formula: 1/Sn = i/(Sn - 1) • Where: Sn = Future Factor of one i = effective rate of interest n = number of compounding periods
Present Value of One • Also known as the PW of 1 • Formula: 1 / Sn = 1 / (1 + i)n • Where: Sn = Future Factor i = effective rate of interest n = number of compounding periods
Present Value of OneAn Example Future Investment $1.00 Nominal Interest Rate 10.0% Holding Period in Years 5 Assumes Annual Compounding One (1) divided by the five (5) year future value factor equals the required deposit to accumulate $1.00 in five (5) years or 1/1.610151 = 0.62092 Deposit $0.62 today and in five years accumulate with 10% compound interest, $1.00
Present Value of One per Period • Also known as the PW of 1/pd • Formula: an = (1 - 1/Sn) / i Where: an = Level Annuity Factor 1/Sn = Present Value Factor i = effective rate of interest n = number of compounding periods
Present Value of One per PeriodAn Example • Can be calculated as a series of single reversions (Present Value of 1) • Can use a table of factors to calculate • Can use a financial calculator to calculate the value, or extract a factor
Level Periodic Installment • Also known as the Installment Factor • Formula: 1/an = i/(1 - 1/Sn) Where: 1/an = Installment Factor 1/Sn = Present Value 1 per period Factor i = effective rate of interest n = number of compounding periods
Relationships • Future Worth of One is the reciprocal of the Present Worth of One • Amortization Factor is the reciprocal of the Present Worth of One per Period • Sinking Fund Factor is the reciprocal of the Future Worth of One per Period
Relationships • Any Future Worth of 1 per Period can be derived by adding the future worth of one factor for the preceding year to the same year factor for the future worth of one per period factor. • Example: FW1, year 1 @ 10% = 1.100 FW1/pd, year 1 @ 10% = 1.000 Sum of two factors = FW1/pd, year 2 or 2.100
Relationships • Any Present Worth of 1 per Period can be derived by adding the present worth of one factor for the number of years factor that is desired. • Example: PW1, year 1 @ 10% = 0.909091 PW1, year 2 @ 10% = 0.826446 PW1, year 3 @ 10% = 0.751315 Sum of three factors = PW1/pd, year 3 or 2.486852
So That’s Compound Interest Are there any Questions? Wayne Foss, MBA, MAI, CRE, Fullerton, CA USA Email: waynefoss@usa.net