EMI Formula Explained — How Banks Calculate Loan EMI
Derive the EMI formula for reducing balance loans. Monthly rate, tenure, amortization, and worked examples for Indian home loans.
What is EMI?
EMI (Equated Monthly Installment) is the fixed monthly payment on a term loan. Each EMI pays interest on the outstanding balance plus a portion of principal. Early EMIs are interest-heavy; later ones repay more principal.
The EMI Formula
EMI = P × r × (1 + r)^n / ((1 + r)^n − 1)
- P = Loan principal (₹)
- r = Monthly interest rate = annual rate ÷ 12 ÷ 100
- n = Tenure in months
This is the standard reducing balance formula used by Indian banks for home, car, and personal loans.
Worked Example
Loan: ₹50,00,000 at 8.5% p.a. for 20 years (240 months)
- r = 8.5 / 12 / 100 = 0.00708333
- EMI ≈ ₹43,391
- Total payment ≈ ₹1.04 crore
- Total interest ≈ ₹54.1 lakh
Verify with EMI Calculator — includes full amortization schedule.
Amortization Breakdown
| Month | EMI | Interest | Principal | Balance |
|---|---|---|---|---|
| 1 | 43,391 | 35,417 | 7,974 | 49,92,026 |
| 240 | 43,391 | ~320 | ~43,071 | 0 |
Interest each month = outstanding × r. Principal portion = EMI − interest.
Flat Rate vs Reducing Balance
Some lenders quote flat rate — interest calculated on full principal entire tenure. Reducing balance is cheaper for same nominal rate. Always compare total interest paid, not just EMI headline.
Prepayment Impact
Extra principal payment reduces future interest. Even one extra EMI per year can shorten tenure significantly. Model scenarios in our calculator.
Related Guides
- EMI Calculation Guide — practical tips
- Compound Interest — related math
- Simple Interest — contrast with loan math
Frequently Asked Questions
Why divide annual rate by 12?
EMI is monthly — interest accrues per month on outstanding balance.
Can EMI change during the loan?
Fixed-rate loans: EMI constant. Floating-rate: EMI or tenure adjusts when benchmark rate changes.
What is processing fee?
One-time bank charge separate from EMI — not in formula but affects total cost.
Is EMI tax deductible?
Home loan principal (80C) and interest (24b) may qualify — consult a CA for current rules.
Does Numverto store my loan data?
No — all calculations run locally in your browser.
Share this article
Learn Faster with Numverto
Explore free number system converters, binary tools, EMI calculators, GST calculators, and educational guides.
About Numverto
Numverto Editorial Team
Numverto publishes educational content about number systems, computer science concepts, binary arithmetic, financial calculations, EMI formulas, GST calculations, and practical learning resources for students and professionals.
Article Metadata
Tags: emi, loans, finance, india
Last Updated: May 2026
Related Calculators
Related Articles
13 June 2026
Simple Interest vs Compound Interest — Formula and Examples
Understand the difference between simple interest and compound interest with formulas, worked examples, comparison tables, and free calculators.
Read article →12 June 2026
How to Calculate Percentage — 3 Types with Examples
Learn three types of percentage calculations with formulas and worked examples: finding percent of a number, what percent one number is of another, and percent change.
Read article →28 May 2026
GST Tax Slabs in India — Quick Reference Guide
Overview of GST rate slabs 0%, 5%, 12%, 18%, 28% in India. CGST, SGST, IGST explained with calculation examples.
Read article →