How to Use the Prepayment Calculator
- Enter your current remaining Loan Outstanding Balance (or original loan amount).
- Input the annual interest rate on your loan (e.g., 8.75% for home loan, 12% for personal loan).
- Specify the remaining loan tenure in months or years.
- Select your prepayment strategy: "One-Time Lump Sum", "Monthly Extra Prepayment", or "Annual Extra Prepayment".
- Input your prepayment amount and the starting month.
- Choose whether you want to "Reduce Loan Tenure" (keep EMI constant) or "Reduce Monthly EMI" (keep tenure constant).
- Instantly see total interest saved, months reduced, and side-by-side comparison tables.
Loan Prepayment Mathematics Explained
When you make a loan prepayment, 100% of the extra amount goes directly towards reducing the Principal Balance (P). The lender then recalculates the loan schedule: • If reducing tenure: Monthly EMI remains unchanged, but because the interest component (P × r) shrinks drastically, a larger fraction of every regular EMI goes towards principal, accelerating loan closure. • If reducing EMI: The remaining tenure is kept identical, and the new EMI is recalculated on the lower principal balance: New EMI = [P_new × r × (1 + r)^rem_months] / [(1 + r)^rem_months - 1].
Home Loan: One-Time Lump Sum Prepayment
Loan: ₹30 Lakhs | Rate: 8.75% | Remaining: 20 Years (240 Mos) | Prepayment: ₹3 Lakhs at Month 12 | Strategy: Reduce Tenure
Original Total Interest = ₹33,62,729. Paying ₹3 Lakhs extra in Year 1 slashes the principal. New tenure is reduced to 199 months (41 months saved).
Interest Saved: ~₹7.25 Lakhs | Tenure Reduced by: 3 Years 5 Months (41 Months) | New Loan Duration: 16.6 Years
Home Loan: Extra ₹5,000 Monthly Prepayment
Loan: ₹40 Lakhs | Rate: 8.5% | Remaining: 20 Years | Extra Monthly: ₹5,000 from Month 1
Standard EMI = ₹34,713. Paying ₹39,713 each month accelerates principal payoff exponentially.
Interest Saved: ~₹13.4 Lakhs | Tenure Reduced by: 5 Years 4 Months (64 Months) | Debt-Free in: 14.6 Years
Personal Loan: Annual Bonus Prepayment
Loan: ₹10 Lakhs | Rate: 13.0% | Remaining: 5 Years (60 Mos) | Prepayment: ₹1 Lakh every year
Original Interest = ₹3,65,183. Paying ₹1 Lakh at the end of each year clears the loan in under 3.5 years.
Interest Saved: ~₹1.48 Lakhs | Tenure Reduced by: 19 Months | Debt-Free in: 41 Months
Prepayment Tips
- ✓Prepaying early in your loan tenure (Years 1 to 7 of a 20-year loan) yields maximum interest savings because the early EMIs are heavily front-loaded with interest.
- ✓RBI mandates that banks and NBFCs cannot charge foreclosure/prepayment penalties on floating-rate home loans and personal loans to individual borrowers.
- ✓Choosing "Reduce Tenure" saves 3x to 5x more total interest than choosing "Reduce EMI".
- ✓Use annual financial windfalls (such as corporate bonuses, tax refunds, or maturing FDs) to make annual lump-sum prepayments.
- ✓Compare prepaying vs investing: if your home loan rate is 8.5% and your equity mutual fund SIP delivers 12%+, mathematically investing surplus cash might create higher net wealth, but prepaying guarantees a risk-free 8.5% return and psychological peace of mind.
Pitfalls to Avoid
- ✗Delaying prepayments until the final 5 years of a 20-year loan, when you have already paid over 80% of total interest.
- ✗Choosing to reduce EMI instead of tenure, which provides short-term cash relief but minimizes total interest savings.
- ✗Prepaying without checking if your lender requires written notification to adjust the principal rather than holding funds as advance EMIs.