What this tool does
An equated monthly instalment is the fixed payment that splits a loan into equal parts each month, with the interest share falling and the principal share rising over time. This calculator returns the instalment, the total interest you will pay over the life of the loan, and a month-by-month schedule showing exactly how that balance changes.
How it works
The instalment is found with the standard annuity formula: EMI equals P times r times one plus r to the power n, divided by one plus r to the power n minus one. P is the principal borrowed, r is the monthly interest rate as a decimal, and n is the total number of monthly payments.
Your quoted annual rate is almost never the rate you actually pay. In most markets the nominal rate is divided by twelve to give r, but some lenders add fees or round up, so the effective rate ends up higher. Compare the total interest from this calculator against the total the lender quotes, not just the monthly figure.
Interest in each period is charged on the outstanding principal at that moment, which is why early instalments are mostly interest and later ones are mostly principal. That is also why extending the term always lowers the instalment while raising the total interest: you are borrowing the same money for longer.
Worked example
A 300,000 loan at 8.5% annual interest over 20 years (240 months).
- Principal P = 300,000
- Monthly rate r = 0.085 / 12 = 0.0070833
- Number of payments n = 240
Monthly payment ≈ 2,603.47. Total repaid ≈ 624,832.73, of which 324,832.73 is interest. Note that over a 20-year term the interest exceeds the amount borrowed.
Accuracy and limitations
- This is an estimate using the standard reducing-balance method. Balloon payments, stepped instalments, and overdraft-style structures are not modelled.
- It excludes insurance, processing fees, and any prepayment penalty, so it will sit slightly below what a lender's schedule shows.
Frequently asked questions
- How is a monthly EMI actually calculated?
- It is the present value of an annuity. Because interest is charged on the reducing balance, the same principal is repaid over many months at a declining rate, so the formula is a geometric series rather than simple division. The result is the one payment that exactly clears the balance after n months.
- Why does extending the tenure lower my EMI but raise my total?
- A longer term spreads the same principal over more instalments, so each payment is smaller. But interest accrues for more periods, so the total paid increases. If you can afford a shorter term, the total cost drops sharply — that is the single biggest lever most borrowers have.
- Should I compare loans by EMI or by total interest?
- Total interest. A lower EMI usually means a longer term, which usually means more interest. Two offers with very different instalments can cost nearly the same, and comparing only the monthly number hides the real difference.
- Does the annual rate need dividing by twelve?
- For a standard reducing-balance loan, yes, the nominal annual rate is divided by twelve to get the monthly rate used above. Be aware that some lenders quote a rate that already reflects compounding differently, and a few add mandatory fees, which is why the effective cost can exceed the headline rate.
- Is my loan data sent anywhere?
- No. The calculation runs entirely in your browser. Nothing you type is transmitted, stored, or logged.