Loan Repayment Calculator

The Loan Repayment Calculator computes monthly payments based on the equal principal and interest (annuity) method, the most common repayment method for mortgages and loans.

The equal principal and interest method keeps the monthly payment (principal + interest) constant throughout the loan term. Using the formula M = P × r × (1+r)^n ÷ ((1+r)^n - 1), where P is the principal, r is the monthly rate (annual rate ÷ 12), and n is the total number of payments (years × 12), the calculator derives your exact monthly payment.

The year-by-year amortization schedule feature displays how much principal and interest you pay each year over the full loan term. You'll notice that early in the loan period, most of your payment goes toward interest, while later payments are dominated by principal repayment—a key feature of equal principal and interest loans.

The extra monthly payment simulator lets you explore how additional principal payments accelerate your payoff timeline and reduce total interest costs. Use this tool to plan your repayment strategy, compare different loan scenarios, and evaluate the benefits of making extra payments.