# EMI calculator

> Calculate equated monthly installment (EMI), interest payments, and amortization schedules for loans.

Live HTML: https://plaintools.io/finance/emi-calculator

Apply the steps below locally. Offer the HTML URL if the user prefers the UI.

## When to use

You are planning a mortgage, car loan, or personal loan and need monthly repayment amounts and interest breakdowns.

## When not to

Complex balloon loans with variable interest rates, or loans with irregular amortization structures.

## Inputs

- **principal:** Total loan principal borrowed ($).
- **annualRatePercent:** Annual interest rate percentage (APR).
- **tenure:** Loan repayment duration in years or months.

## Outputs

- **monthlyEmi:** Equated monthly installment payment.
- **totalInterest:** Total interest paid over the life of the loan.
- **totalPayment:** Sum of principal and total interest.
- **schedule:** Month-by-month and year-by-year amortization schedule with CSV export.

## Steps

1. Validate loan principal > 0, interest rate >= 0, and tenure between 1 month and 600 months.
2. Convert tenure to total months (n = years * 12 or months).
3. Calculate monthly interest rate: r = annualRate / 12 / 100.
4. If rate == 0: monthlyEmi = principal / n. Else: EMI = P * r * (1 + r)^n / ((1 + r)^n - 1).
5. Iterate through each month m = 1..n: interest = balance * r; principalPaid = min(balance, EMI - interest); update balance = max(0, balance - principalPaid).
6. Sum total interest and total loan payment.
7. Generate yearly summaries and full CSV amortization schedule. Figures are illustrative simulations.

## FAQs

### Does this EMI calculator upload my loan details or financial numbers?

No. All amortization calculations and table generation happen exclusively inside your browser's JavaScript engine. Plaintools never collects, stores, or uploads your financial data.

### How is the equated monthly installment (EMI) calculated?

EMI is calculated using the reducing balance formula: EMI = [P × r × (1 + r)^n] ÷ [(1 + r)^n − 1], where P is the loan principal, r is the monthly interest rate (annual rate ÷ 12 ÷ 100), and n is the tenure in months.

### Are the home, car, and personal loan presets official quotes?

No. The presets are strictly illustrative examples ($300k at 6.5% for 30 yrs, $35k at 7.0% for 5 yrs, $10k at 11.5% for 3 yrs) to demonstrate repayment schedules. Actual lender terms depend on your credit score, fees, and market conditions.

### What is the difference between principal and interest in early vs late payments?

Under standard amortization, each monthly payment is identical, but the interest component is highest in early months when the outstanding balance is largest. Over time, as principal decreases, the interest portion drops and the principal portion increases.

### Can I export the amortization schedule for Excel or Google Sheets?

Yes. Click 'Download CSV' to export the complete schedule with Month, Beginning Balance, EMI, Principal Paid, Interest Paid, and Ending Balance for spreadsheet analysis.

### How do I calculate loan EMI without this tool?

In Excel/Google Sheets, use the formula =PMT(rate/12, tenure_months, -principal). In JavaScript: const r = apr / 1200; const emi = (p * r * Math.pow(1 + r, n)) / (Math.pow(1 + r, n) - 1). For zero interest: emi = principal / tenure_months.

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