Loan Prepayment Calculator: How Prepaying Saves Lakhs in Interest
One Extra EMI Per Year Saves 7 Years on a 20-Year Home Loan
This counterintuitive math is why loan prepayment is the single most powerful financial move for anyone with a home loan. In the early years of a long-tenure loan, over 75% of your EMI goes toward interest. A prepayment attacks the principal directly, reducing the base on which interest is calculated for every remaining month.
Worked Example: ₹50L Home Loan at 8.5%
| Scenario | Tenure | Monthly EMI | Total Interest | Savings |
|---|---|---|---|---|
| No prepayment | 20 years | ₹43,391 | ₹54,14,000 | — |
| 1 extra EMI/year | ~13.5 years | ₹43,391 | ₹33,80,000 | ₹20,34,000 |
| ₹1L prepayment every year | ~12 years | ₹43,391 | ₹29,60,000 | ₹24,54,000 |
By paying just one extra EMI each year (roughly ₹43,000), you save over ₹20 lakh in interest and finish 6.5 years early. The power comes from compounding in reverse — every rupee of principal saved today prevents interest charges across hundreds of remaining instalments.
When Prepayment Works Best
- Early in the loan tenure: In year 1 of a 20-year loan, ~75% of EMI is interest. A ₹1L prepayment saves more than the same amount prepaid in year 15.
- When interest rate is high: The higher the rate, the more you save per rupee of prepayment.
- Floating rate loans: Prepayment reduces your exposure to future rate hikes.
When NOT to Prepay
- If you have higher-interest debt: Credit card debt at 36% should be paid before a home loan at 8.5%
- If you lack emergency fund: Keep 6 months of expenses liquid before making lump-sum prepayments. Use the emergency fund calculator to find your target.
- If investments earn more than loan rate: If your SIP returns 14% and your loan costs 8.5%, investing might beat prepayment (but this involves market risk)
- If prepayment penalty applies: Some fixed-rate loans charge 2–4% penalty on prepaid amounts
Reduce Tenure vs Reduce EMI
When you make a prepayment, most banks give you two choices:
| Option | When to Choose |
|---|---|
| Reduce tenure (keep EMI same) | Saves more interest. Choose this if your EMI is comfortable. |
| Reduce EMI (keep tenure same) | Improves monthly cash flow. Choose this if EMI strains your budget. |
Always choose "reduce tenure" if you can afford it — the interest savings are significantly higher. Use the prepayment calculator to compare both options side by side.
RBI Rules on Prepayment
For floating rate home loans, RBI has mandated that banks cannot charge any prepayment penalty. For fixed rate loans and non-housing loans, penalties may still apply. Always check your loan agreement for prepayment terms before making large payments.