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Next toolsAssumptions and methodology
Transparent calculation notes for Fixed Principal Loan Calculator.
Formula used
The principal part is constant each month while interest declines as the outstanding balance reduces.
Methodology
- Divide loan amount by total months to get fixed monthly principal.
- Calculate interest each month on the opening balance.
- Reduce the balance by the fixed principal amount.
Core assumptions
- The interest rate remains unchanged.
- Principal repayment is equal every month.
- All scheduled payments are made on time.
Not included
- Fees, floating-rate resets, penalties, moratoriums, and lender day-count rules are excluded.
- Some real loans may not use exact equal-principal amortization.
About Fixed Principal Loan Calculator
Guide1What is a Fixed Principal Loan?
A Fixed Principal Loan (also called an equal-principal loan) is a repayment structure where the principal repayment remains constant throughout the loan tenure, while the interest is calculated on the reducing balance. This results in higher payments initially that decrease over time as the outstanding principal reduces.
This structure is different from the standard EMI model where the total payment (principal + interest) remains constant. Fixed principal loans are common in business loans and certain agricultural credit facilities in India.
2How Fixed Principal Loans Differ from EMI Loans
- Payment Pattern: Fixed principal loans have decreasing monthly payments; EMI loans have constant payments
- Total Interest: Fixed principal loans typically result in lower total interest paid compared to EMI loans
- Initial Burden: Monthly payments are higher in the beginning but reduce over time
- Cash Flow: Suits borrowers who expect stable or decreasing expenses over time
3Fixed Principal vs Flat-Rate Loans
A flat-rate loan charges interest on the full original amount for the whole tenure. A flat 8.5% on ₹20 lakh for 20 years costs ₹34,00,000 in interest, and you'd pay ₹22,500 every month, which is only the first payment here. As a rule of thumb, a flat 10% over 3 years costs about the same as an 18% reducing-balance rate.
This calculator uses the reducing balance, so it doesn't show flat-rate costs.
4Fixed Principal Loan Formula
Each monthly payment is calculated as:
Monthly Payment = (P / n) + (Outstanding Balance × r / 12)
- P / n = Fixed principal component each month
- Outstanding Balance = Remaining loan amount, decreasing each month
- r = Annual interest rate
The first month's payment is the highest, and each subsequent month the interest component decreases.
5How to Use This Calculator
- Step 1: Enter the total loan amount
- Step 2: Input the annual interest rate
- Step 3: Set the loan tenure in years
- Step 4: See the yearly schedule: what you pay each year, split into principal and interest, and the balance left. Switch to monthly to see every payment
- Step 5: Compare with a standard EMI on the same loan: the interest saved, how much higher the first payment is, and the month your payment drops below the EMI