Nine mistakes people make with an EMI calculator

• Entering the property or vehicle price instead of the loan amount, so the down payment is never subtracted.
• Entering a flat rate into a reducing-balance calculator, which understates the cost substantially.
• Mixing years and months — 5 means five years in one field and five instalments in another.
• Ignoring fees, which raise the real cost without changing the EMI.
• Assuming today's floating rate holds for 20 years; test a rate one or two percentage points higher.

• Judging a loan by its EMI alone and picking the longest tenure without seeing the interest it adds.
• Forgetting that a part-disbursed home loan charges pre-EMI interest before full instalments begin.
• Assuming a prepayment automatically shortens the tenure, when some lenders reduce the EMI instead.
• Treating the calculator's output as an eligibility or approval decision, which depends on income, credit history and lender policy.

Total interest should be plausible: on a 20-year loan at 8–9% it is roughly the same size as the principal; on a 5-year loan at 11% it is nearer a quarter of it.

Month 1 interest should equal principal × annual rate ÷ 1200. If that does not match the schedule, an input is wrong.

Compare the calculated EMI with your sanction letter. A few rupees apart is rounding; hundreds apart means the rate, tenure or amount differs.

The most useful thing a calculator does is not the instalment — it is showing what a small extra payment does to the total. Run your loan once as it stands, then again with the extra you could realistically manage, and compare the two closure dates.