HaatBeatBeyond the numbers
The maths shows one side. These are the things only you can weigh.
- Peace of mind and psychological safetyDebt can feel like a weight. Some people sleep better debt-free. Others feel secure knowing they have cash and can handle setbacks. Both are real; neither is wrong.
- Liquidity and emergenciesCash in investments is available (though selling may take days and have tax implications). A loan obligation is fixed. If job loss or illness is a real risk, keeping cash is wise.
- Job and income securityIf your income is stable and growing, investing may work well. If your work is uncertain, the security of lower debt might matter more than higher wealth on paper.
- Your discipline to actually investThis calculator only works if you invest the freed EMI or upfront money. If you're likely to spend it instead, prepaying removes temptation by locking the money into forced debt repayment.
- Prepayment charges and fine printSome loans have penalties for prepayment. Check your loan documents. A 2% prepayment charge, for example, can swing the math significantly.
- Risk tolerance and market swingsInvestments go up and down month to month. A certain interest saving (from prepayment) can feel safer than returns that vary. Your comfort with volatility matters.
- Family responsibilities and goalsChildren's education, a home purchase, or caring for parents might change which option fits. A flexible line of credit (if you prepay) can help with surprises.
How it's calculated
The EMI (equal monthly payment) is calculated for the original loan using the formula (P × r × (1+r)^n) / ((1+r)^n − 1), where r is the monthly rate. For prepayment, the freed EMI is invested at the assumed return rate. For investing, the lump sum grows at the return rate. Both strategies grow money until the original loan end date.
Assumptions
- The loan has a fixed interest rate and fixed end date.
- You keep paying the same EMI if you prepay; the loan ends early instead.
- You actually invest the money freed by early prepayment.
- Investment returns compound monthly at one-twelfth of the annual rate.
- Loan and investment rates remain constant over the period.
- No prepayment charges, taxes, inflation or investment variability are included.
Worked example
A 30 lakh rupee loan at 8.5% with 15 years left has an EMI of about 29,542 rupees. Prepaying 5 lakh rupees ends the loan 50 months early and saves about 9.89 lakh rupees of interest. Investing the 5 lakh at 10% instead ends about 3.87 lakh rupees ahead at the original end date; at a return equal to the loan rate, the two are the same.
Questions
Which option is "right" for me?
This calculator shows the numbers, but both have non-financial benefits. Prepaying gives peace of mind and removes the obligation sooner. Investing keeps liquidity for emergencies. Your choice depends on your job security, risk tolerance, and personal values.
Why might the options be different if the rates are the same?
The timing matters. When you prepay, you invest the freed EMI each month going forward. When you invest upfront, your money grows from day one. These compounding patterns differ and create a gap in final wealth.
What if I can't actually invest the freed EMI?
If you don't invest the freed payment after prepayment, prepaying is usually better: you've paid off debt and saved interest. This calculator assumes you do invest it, so your numbers matter only under that assumption.
What happens if investment returns are negative or vary?
This calculator assumes a fixed return every year. Real markets vary. Try running the calculation with different return rates (e.g., 5%, 10%, 15%) to see how sensitive the outcome is to your return assumption.
Does this account for taxes on investment gains or tax relief on loan interest?
No. Tax treatment of loan interest and investment returns varies by country, investment type, and your income. Talk to a tax adviser about how your situation works.