Loan & Installment Calculator (with Repayment Schedule)
Calculate the monthly payment, total interest, total amount due, and repayment (annuity) schedule for a loan or installment plan.
Calculate your monthly installment, total interest, and total repayment for a loan based on its interest rate and term — useful for home loans, car loans, personal loans, or business loans. It supports both common calculation methods, reducing-balance interest and flat-rate interest, so you can compare them before signing a contract.
How to use Installment / Loan Interest
- Enter the loan amount and the annual interest rate (%/year).
- Enter the loan term in months.
- Choose the interest calculation method: reducing balance (common at banks) or flat rate on the original principal.
- See your monthly payment, total interest, and total repayment amount.
How is reducing-balance interest different from flat-rate interest?
Reducing-balance interest is calculated only on the remaining principal, so the interest amount decreases each month and the total interest is usually lower. Flat-rate interest is calculated on the entire original loan amount for the whole term, which keeps the monthly interest fixed and makes the total interest higher — even if the advertised "%/year" figure looks low.
Why do I still pay so much even though the advertised rate looks low?
Some lenders quote flat-rate interest to make the number look attractive. When converted to the effective rate (reducing-balance basis), the real cost can be nearly double. Always ask which method is being used, and use this tool to compare the total interest between the two options before you decide.
Should you choose a long or short loan term?
A longer term makes your monthly payment lighter but increases the total interest paid. A shorter term does the opposite. Choose a monthly payment that fits your income (typically no more than 40–50% of your income) so you don't end up under financial pressure.
Frequently asked questions
What is reducing-balance interest?
It's a method that calculates interest only on the remaining principal, so the interest amount decreases each month — usually more favorable than calculating on the original principal.
Why does the bank quote a low rate but I still pay a lot?
Many lenders advertise flat-rate interest (calculated on the original loan amount for the whole term), which makes the effective rate higher than the advertised figure. Convert it to a reducing-balance basis to compare fairly.
Does paying off the loan early reduce the interest?
With the reducing-balance method, prepaying reduces the principal and thus lowers interest in later periods — but many contracts include an early-repayment penalty, so read the terms carefully.
Does the tool calculate correctly for home loans?
Yes. Enter the loan amount, annual interest rate, and term in months; the tool calculates the monthly payment using the reducing-balance method, just like most home loans.