Repayment Calculator

Introduction

This Repayment Calculator generates a period-by-period amortization schedule for a fixed-rate loan with equal monthly payments. Enter loan amount, annual interest rate, and term to see each payment's principal and interest components plus remaining balance until zero. Use it when you need the table a lender attaches to disclosures, for tax interest logging, or for verifying that extra payments hit principal as expected. The schedule is the authoritative view of how a fixed note retires over time when no prepayment penalties or rate changes interrupt the path.

Who this calculator is for

Borrowers who want the full grid behind a single monthly payment figure belong here. Accountants tracking deductible interest on a business installment loan, students reconciling promissory note examples, and buyers verifying dealer math all use repayment schedules.

If you only need payment total without line-by-line detail, the Loan Calculator is faster. If you need to solve for payment from affordability, use the Payment Calculator first then paste results here.

What it estimates

Payment is computed once from standard amortization formula. Each row adds interest on opening balance, subtracts payment, records principal portion, and closes with ending balance. Sum of principal columns equals original loan; sum of interest columns equals total finance charge.

Optional extra payment columns may shorten the schedule when enabled. Balloon notes, skip payments, and rate changes midstream are unsupported.

Inputs explained

Align term length with the note; off-by-one month errors shift every row.

• Loan amount: Original principal funded, such as $15,000.
• Annual interest rate: Fixed APR for the life of the loan, such as 8.5%.
• Term in months: Count of equal payments, 36 for three years.
• First payment date: Labels the schedule; optional for math.
• Extra monthly payment: Optional additive amount applied to principal each period.

How to read the results

Early rows show interest-heavy payments; later rows flip toward principal. Remaining balance should hit zero on the final row without a residual penny, aside from rounding. Export or print for year-end interest totals by summing interest cells for calendar years.

Compare row twelve interest with your Form 1098 if a mortgage-like product; consumer loans may not mail forms but logic is identical.

Worked example

$15,000 at 8.5% APR for 36 months yields a payment near $473. Month one: interest about $106 on $15,000, principal about $367, balance near $14,633. Month thirty-six: interest only a few dollars, principal almost the full payment. Total interest about $2,030 over three years.

Add $100 extra principal monthly and regenerate. Last payment arrives before month thirty-six and total interest drops by several hundred dollars. Highlight the row where balance crosses below $10,000 for mental milestones.

Practical use cases

Business books: split monthly auto debit into interest expense and liability reduction. Verify lender portal balance against calculated balance after six payments. Franchise owners reconciling multiple unit loans can run one row per note and compare combined debt-free date against corporate covenant deadlines.

Gift planning: show a relative how a $15,000 family loan at a fair IRS rate amortizes. Pair with Student Loan Calculator when comparing federal standard ten-year against private three-year schedules. Auditors sampling one year can sum interest cells for January through December without rebuilding the loan from statements.

Limitations and related tools

360-day conventions, Rule of 78s prepayment penalties, and biweekly payment programs differ from pure monthly tables. Some lenders apply payments a day late, shifting interest microscopically.

Revolving credit without fixed term: Credit Card Calculator. Multiple debts: Debt Payoff Calculator. Effective rate with fees: APR Calculator.

How It Works

1. Enter loan terms. Type principal, APR, and term in months matching the signed note.
2. Generate schedule. Click Calculate to produce payment summary and full amortization table.
3. Scan key rows. Check first payment, midpoint balance, and final zero row for sanity.
4. Model extra principal. Add optional extra payment and recalculate to see shortened schedule and interest saved.

Formula and methodology

The Repayment Calculator uses this identity for the scenario you enter. A bank, payroll system, or tax program may round on a 360-day year or average daily balance, so a statement can differ by a small amount.