Loan Calculator – Complete Guide & Free Online Tool

A loan calculator estimates your monthly payment, total paid and total interest for a fixed-rate loan. Free online tool included.

Published 2026-09-13

In this guide
  1. What is Loan Calculator?
  2. Formula
  3. Assumptions
  4. Key Features
  5. Examples
  6. Common Use Cases
  7. Tips & Best Practices
  8. Limitations
  9. Related Tools
  10. External Resources

What is Loan Calculator?

A loan calculator estimates your monthly payment, total paid and total interest for a fixed-rate loan.

Formula

Monthly payment = P × r / (1 − (1 + r)^−n), where r is the monthly rate (annual/12) and n is the number of monthly payments.

Assumptions

The result assumes a fixed interest rate and no extra fees. Actual terms from lenders may differ.

Key Features

• Monthly payment • Total interest • Total paid • Transparent math

Examples

• A $20 • 000 loan at 6% for 5 years has a monthly payment of about $387.

Common Use Cases

• Auto loans • Personal loans • Budgeting

Tips & Best Practices

• Compare lenders by total interest • not just monthly payment.

Limitations

• Does not include fees • taxes or variable rates.

Related Tools

Explore other calculators: [Calculators](/categories/calculators).

Related tools: [mortgage-calculator](/tools/mortgage-calculator), [compound-interest](/tools/compound-interest), [simple-interest](/tools/simple-interest).

External Resources

CFPB: Loan Payments

Related Tools

Mortgage Calculator Estimate monthly mortgage payments and total interest. Calculators Use Tool →
Compound Interest Calculator Calculate compound interest with configurable compounding frequency. Calculators Use Tool →
Simple Interest Calculator Calculate simple interest on a principal over time. Calculators Use Tool →

Frequently Asked Questions

How is a loan payment calculated?
Using the amortization formula: P × r / (1 − (1+r)^−n).
What does the total interest mean?
The extra amount you pay over the principal across the whole term.
Is this a quote?
No, it is an estimate; actual terms depend on the lender.
Is it free?
Yes, and it runs locally.

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