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Loan Calculator - Equal-Installment and Equal-Principal Schedules

Enter the loan principal, annual interest rate, and repayment term to see monthly payments and total interest for equal-installment and equal-principal loans, along with a full amortization schedule.

Monthly payment

Equal installment versus equal principal, what is different

The same loan can carry different monthly payments and total interest depending on the repayment method. Equal-installment repayment keeps the monthly payment (principal plus interest) the same, so interest weighs heavier early on and principal takes over later. Equal-principal repayment fixes the principal portion each month while the interest declines, which means a heavier early burden but lower total interest overall.

This calculator handles both methods, computing the monthly payment, total interest, and total repayment, and it lays out a full schedule showing principal, interest, and balance for each month. Use it to compare loan products or build a repayment plan that fits you.

How to use it

  1. Enter the loan principal, annual interest rate, and repayment term.
  2. Pick equal installment or equal principal as the repayment method.
  3. Press Calculate to see the monthly payment and amortization schedule.

Good times to use it

  • Comparing repayment methods for a mortgage
  • Understanding the interest structure of personal or auto loans
  • Seeing how the interest changes when you lengthen or shorten the term
  • Deciding whether an early repayment makes sense

Frequently asked questions

Equal-installment repayment keeps the monthly total the same, with interest taking a larger share early on. Equal-principal repayment fixes the principal portion each month while the interest declines, so the early burden is heavier but total interest is lower.

No. This calculator assumes repayment runs to maturity. Early repayment fees depend on the loan contract, so check with the lender for the exact figure.

The annual rate is divided by 12 to get a monthly rate, and interest is charged on the remaining balance each month. Most loans work the same way, so the result is close to reality.

Because the principal is paid down by a fixed amount each month, the balance shrinks faster, and so does the interest. If you can handle the heavier early payments, total interest drops significantly.

No. This is a straightforward calculation under fixed assumptions. Real loans can vary by loan type, interest calculation method, fees, and grace periods, so treat the result as a reference.

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