# Financial Calculator

##### This page contains forms for computing the financial formulas described in the book:
YOU CAN DO THE MATH
Overcome Your Math Phobia and Make Better Financial Decisions

by Ron Lipsman

##### Each form gives the actual formula that is used. You only need to enter your data; the form will perform the appropriate computation for you and return the result of evaluating the formula using your data.

Chapter 1. Saving for a College Education

Lump Sum Account--Final Value
Simple Annual Interest
 V = D(1+r)nD is the amount deposited, r is the interest rate,n is the number of years, and V is the final amount.Let D = Let r = Let n =

Daily Compounded Interest
 V = D(1 + r/365)365nD is the amount deposited, r is the interest rate, n is the number of years, and V is the final amount.Let D = Let r = Let n =

Lump Sum Account--Target Value
Simple Annual Interest
 D = V/(1+r)nV is the final target value of the account, r is the interest rate,n is the number of years, and D is the initial amount you must deposit.Let V = Let r = Let n =

Daily Compounded Interest
 D = V/(1 + r/365)365nV is the final target value of the account, r is the interest rate, n is the number of years, and D is the initial amount you must deposit.Let V = Let r = Let n =

Chapter 2. Investing for a College Education

Regular Deposit Account--Final Value

Annual Deposit, Simple Annual Interest
 V = D(1 + r)[(1 + r)n - 1] / rD is the amount deposited annually, r is the interest rate,n is the number of years, and V is the final amount.Let D = Let r = Let n =

Annual Deposit, Daily Compounded Interest
 V = D(1 + r/365)365[(1 + r/365)365n - 1]/[(1 + r/365)365 - 1]D is the amount deposited annually, r is the interest rate,n is the number of years, and V is the final amount.Let D = Let r = Let n =

Monthly Deposit, Daily Compounded Interest
 V = D(1 + r/360)30[(1 + r/360)360n - 1]/[(1 + r/360)30 - 1]D is the amount deposited monthly, r is the interest rate,n is the number of years, and V is the final amount.Let D = Let r = Let n =

Biweekly Deposit, Daily Compounded Interest
 V = D(1 + r/364)14[(1 + r/364)364n - 1]/[(1 + r/364)14 - 1]D is the amount deposited biweekly, r is the interest rate,n is the number of years, and V is the final amount.Let D = Let r = Let n =

Weekly Deposit, Daily Compounded Interest
 V = D(1 + r/364)7[(1 + r/364)364n - 1]/[(1 + r/364)7 - 1]D is the amount deposited weekly, r is the interest rate,n is the number of years, and V is the final amount.Let D = Let r = Let n =

Regular Deposit Account--Target Value

Annual Deposit, Simple Annual Interest
 D = V/[(1 + r)[(1 + r)n - 1] / r]V is the final target value of the account, r is the interest rate,n is the number of years, and D is the amount deposited annually that is required.Let V = Let r = Let n =

Annual Deposit, Daily Compounded Interest
 D = V/[(1 + r/365)365[(1 + r/365)365n - 1]/[(1 + r/365)365 - 1]]V is the final target value of the account, r is the interest rate,n is the number of years, and D is the required amount deposited annually.Let V = Let r = Let n =

Chapter 3. Taking into Consideration Taxes and Inflation

Inflating Prices
 P = P0(1 + r)nP0 is the price of an item initially, r is the annual inflation rate,n is the number of years, and P is the final price.Let P0 = Let r = Let n =

After-Tax rate of Return
 ra = r(1 - b/100)r is the stated rate of return, b is the marginal income tax bracket,and ra is the actual after-tax rate of return.Let r = Let b =

Effect of Taxes on a Simple Annual Interest Account
 V = D(1+rb)nD is the amount deposited, r is the interest rate,n is the number of years, b is the marginal tax rate, rb = r(1-b/100) is the effective yield, and V is the final amount.Let D = Let r = Let b = Let n =

Chapter 4. Tax-Deferred Accounts Can Help

Taxable versus Tax-Deferred; Simplest Model
 V = D(1 + r)[(1 + r)n - 1] / r, in the tax-deferred accountV = D(1 + rb)[(1 + rb)n - 1] / rb, in the taxable account, rb=r(1-b/100)D is the amount deposited annually, r is the interest rate,n is the number of years, b is the marginal income tax bracket, and V is the final amount.Let D = Let r = Let n = Let b =

Taxable versus Tax-Deferred; Complex Model
 V = (1-b/100)D(1 + r)[(1 + r)n - 1] / r, in the tax-deferred accountV = (1-b/100)D(1 + rb)[(1 + rb)n - 1] / rb, in the taxable account, rb=r(1-b/100)D is the amount available (before taxes) annually, r is the interest rate,n is the number of years, b is the marginal income tax bracket, and V is the final amount.Let D = Let r = Let n = Let b =

Freedom Quotient
 FQ = AT/G is your after-tax income, G is your gross salary,FQ is your freedom quotient.Let AT = Let G =

Chapter 6. Buying a House or Car: Mortgages and Loans

Loan Payments
 P = B(r/12) / [ 1 - 1/(1+r/12)n ]B is the amount borrowed, r is the interest rate,n is the number of months, and P is the monthly payment.Let B = Let r = Let n =

Loan Amount
 B = P/[(r/12) / [ 1 - 1/(1+r/12)n ]] P is the monthly payment, r is the interest rate,n is the number of months, and B is the amount borrowed.Let P = Let r = Let n =

Magic Number
 MN = (r/12) / [ 1 - 1/(1+r/12)n ]r is the interest rate, n is the number of months,and MN is the magic number.Let r = Let n =

Total Payments
 TP = nP = nB(r/12) / [ 1 - 1/(1+r/12)n ]B is the amount borrowed, r is the interest rate,n is the number of months, and TP is the total payment.Let B = Let r = Let n =

Total Interest
 TI = TP - Bwhere the formula for TP is given in the form immediately above.B is the amount borrowed, r is the interest rate,n is the number of months, and TI is the total interest paid on the loan.Let B = Let r = Let n =

Lease Payments
 P = (C - R)/n + (C + R)MC is the cap cost, R is the residual value,n is the number of months, M is the money factor,and P is the monthly payment.Let C = Let R = Let n = Let M =

Chapter 10. Cut up those #\$%^& Credit Cards

Credit Card Interest
 I = Br/12B is the outstanding balance, r is the annual interest rate charged by your credit card company,and I is the interest charge for that month.Let B = Let r =

Chapter 12. The Stock Market and Other Investments

Escalating Investment Model
 V = D(1 + r) [(1 + r)n - (1 + s)n] / (r - s)D is the initial amount invested, r is the interest ate,s is the rate at which the amount invested is escalated each year, n is the number of years, and V is the final value.Let D = Let r = Let s = Let n =

Magic Number for an Escalating Investment Program
 MN = (1 + r) [(1 + r)n - (1 + s)n] / (r - s)r is the interest rate, s is the rate at which the amount invested is escalated each year,n is the number of years, and MN is the magic number.Let r = Let s = Let n =

Chapter 13. Retirement

Retirement Account Depletion--Discounting Inflation
How Long Will Your Money Last
 n = ln[S/(S - rE)]/ln(1+r)S is the annual shortfall, E is your nest egg, r is the interest rate, and n is the number of years till depletion of the account.Let S = Let E = Let r =

How Much You Can Spend
 S = (1 + r)nE/[(1 + r)n - 1)/r]E is your nest egg, r is the interest rate, n is the number of years the nest egg must last, and S is the amount you can afford to spend annually.Let E = Let r = Let n =

Retirement Account Depletion--Accounting for Inflation
How Long Will Your Money Last
 n = ln[S/(S - (r - s)E)]/ln[(1+r)/(1+s)]S is the annual shortfall, E is your nest egg, r is the interest rate, s is the inflation rate,and n is the number of years till depletion of the account.Let S = Let E = Let r = Let s =

How Much Can You Spend
 S = (1 + r)nE/[((1 + r)n - (1 + s)n)/(r - s)]E is your nest egg, r is the interest rate, s is the inflation rate, n is the number of years the nest egg must last,and S is the amount you can afford to spend annually.Let E = Let r = Let s = Let n =

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