MCPCalc

Auto Loan Calculator

Calculate car payments with down payment, trade-in value, and loan terms.

Scratchpad (not saved)

$

Price of the vehicle

$

Cash down payment

$

Value of your trade-in vehicle

%

Annual interest rate (APR)

Length of the loan

Fees
%

State/local sales tax rate

What This Calculator Does

Estimate car loan payments and financing cost by combining purchase price, trade-in, down payment, APR, and term length.

It combines Vehicle Price, Down Payment, Trade-In Value, Interest Rate to estimate Monthly Payment, Loan Amount, Sales Tax.

Formula & Method

Core equations: Loan amount after trade-in and down payment: L=P+P×tsales−D−TL = P + P \times t_{sales} - D - T Monthly payment: M=L⋅r(1+r)n(1+r)n−1M = L \cdot \frac{r(1+r)^n}{(1+r)^n - 1} where PP is the vehicle price, tsalest_{sales} is the sales tax rate, DD is the down payment, TT is trade-in value, rr is the monthly rate, and nn is the term in months. Inputs are applied in base units, then derived metrics are computed from the same equations and rounded for display.

Notation used in the formulas: RR = Monthly Payment; x1x_{1} = Vehicle Price; x2x_{2} = Down Payment; x3x_{3} = Trade-In Value; x4x_{4} = Interest Rate; x5x_{5} = Loan Term; x6x_{6} = Sales Tax Rate.

Method summary: inputs are normalized to consistent units, core equations are evaluated, then secondary values are derived and rounded for display.

Use this before dealership negotiations to compare financing structures and understand total borrowing cost.

Reference Book

Mathematics of Investment and Credit

Samuel A. Broverman · ACTEX Learning

A widely used text for time-value-of-money, annuity, loan, amortization, and bond calculations.

View Book

Inputs Used

  • Vehicle Price: Price of the vehicle
  • Down Payment: Cash down payment
  • Trade-In Value: Value of your trade-in vehicle
  • Interest Rate: Annual interest rate (APR)
  • Loan Term: Length of the loan
  • Sales Tax Rate: State/local sales tax rate

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