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Installment Loan

What is an installment loan?

An installment loan is a type of loan that is repaid over time with a set number of scheduled payments. Unlike revolving credit (e.g., credit cards), the loan is fully repaid at the end of the term.

This example demonstrates a fixed principal repayment model, where the borrower pays off the same amount of the loan each year, while interest decreases over time.

Formula

Annual Interest = Remaining Debt * Interest Rate  

Principal Repayment = Total Debt / Loan Term

Annuity (Annual Payment) = Interest + Principal Repayment

Remaining Debt = Previous Debt − Principal Repayment

Example

Assuming a loan of €100,000 with an interest rate of 5% and a fixed annual principal repayment of €25,000 over 4 years:

YearRemaining DebtInterest (5%)Principal RepaymentAnnual PaymentDebt After Payment
1€100,000€5,000€25,000€30,000€75,000
2€75,000€3,750€25,000€28,750€50,000
3€50,000€2,500€25,000€27,500€25,000
4€25,000€1,250€25,000€26,250€0

Total Interest Paid: €12,500
Total Repaid: €112,500