Topic 4 · Loans

Amortization Sandbox

Drag the principal, rate, and term sliders. Watch the monthly payment, total cost, and total interest update live. Below, the balance curve traces how much you still owe each month, and the schedule table shows every payment's split between interest and principal. Pick one of the presets to jump straight to a realistic auto, student, or mortgage scenario.

Loan amortization · ALEKS formula

M = P (r/12) / [ 1 − (1 + r/12)^{−12 t} ]

Borrowing $300,000 at 6.5% for 30 years means $1,896/month and $382,633 total interest paid over the life of the loan.

Monthly payment

$1,896.20

M = P (r/12) / [1 − (1+r/12)⁻¹²ᵗ]

Total cost

$682,633

M × 12 × t

Total interest

$382,633

Total cost − principal

Remaining balance over time Cumulative principal paid Cumulative interest paid

Principal (P) $300,000

$1,000$1,000,000

Annual rate (r) 6.50%

0.1%20%

Term (t) 30 years

1 yr40 yrs

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Amortization schedule — selected payments

Payment	Interest portion	Principal portion	Remaining balance