Most car loan calculators give you a monthly payment estimate and stop there. That is not actually useful information. What you need to know is whether the total interest you pay goes down, by how much, and whether that number justifies the fees and the hassle.
That is what this site is built to answer.
Who Runs This Site
I’m Rebecca Betterton, and my career is dedicated to making the complex world of auto finance transparent for everyday drivers. As a senior analyst and a Certified Financial Education Instructor (CFEI), I’ve spent years reporting on how interest rates, dealership markups, and market shifts impact your wallet.
Why I Built This Tool
Lenders design most auto loan calculators to get you to sign a contract. I wanted to build something different: a conflict-free utility that prioritizes your savings over a bank’s profit.
In my reporting for sites like Bankrate and MSN, I’ve seen how “captive financing” and dealer reserves can trap borrowers in high-interest cycles. This site is my way of giving you the “insider math” needed to break those cycles.
My Expert Standards
Independent Advocacy: I don’t work for a lender. My reputation as a financial journalist is built on providing unbiased, actionable advice to help you pay less for the car you drive.
Data Accuracy: I manually review the Rate Benchmarks on this site to ensure they reflect the current 2026 lending environment.
Technical Oversight: Every formula used, from amortization to breakeven points, is audited for precision.
Our Editorial Standards
This is a financial site. The math has to be right. Here is how we keep it that way:
- All calculator formulas are tested against standard loan contract outputs before publication
- Sample APR rates and vehicle values are updated when market data moves by more than 0.5%
- Every article includes a Last Reviewed date
- We do not accept affiliate commissions, lender referral fees, or sponsored placements that could bias our calculations
- If a formula error is identified, we correct it within 48 hours and note the correction at the bottom of the affected page
What Our Tools Do
Our primary tool is the Auto Loan Refinance Calculator, an amortization engine that models your current loan and a proposed replacement side by side. Unlike basic monthly payment calculators, ours outputs:
- Total interest paid over the life of both loans
- Monthly savings, adjusted for refinance fees
- Breakeven month: the exact point at which savings exceed transaction costs
- Daily-accrual interest modeling for loans that calculate interest on a per-day basis
- A downloadable amortization table showing principal and interest split for every payment
Our Methodology
We use the standard fixed-rate amortization formula used in consumer loan contracts:
M = P × [r(1+r)^n] / [(1+r)^n – 1]
Where M is the monthly payment, P is the principal balance, r is the monthly interest rate (APR divided by 12), and n is the number of remaining payments.
For loans that accrue interest on a daily basis, we apply a simple daily interest model: daily rate = APR / 365, applied to the outstanding balance each day. This is the method most banks use for calculating payoff balances and is why your lender’s payoff quote is always slightly different from your remaining balance on the statement.
What We Do Not Do
We are not a lender, broker, or financial advisor. We do not:
- Originate loans or take applications
- Provide personalized financial advice
- Guarantee that any rate shown is available to you from a lender
- Accept referral fees from lenders or dealerships
All outputs from our calculator are mathematical estimates. Your actual rate, term, and savings will depend on your creditworthiness, vehicle value, lender policies, and state regulations.
Data and Privacy
All calculator inputs are processed locally in your browser. We do not transmit loan details, balances, or personal financial information to our servers. No account is required to use any tool on this site.
For full details on data handling, see our Privacy Policy.
Contact
If you find a calculation error, have a question about a tool, or want to suggest a scenario we have not covered, use the contact form. Rebecca reviews all submissions personally.
Identity Profile Card
| Full Name | Rebecca Betterton |
| Title | Senior Auto Finance Analyst & CFEI |
| Location | New York, NY |
| Experience | 4+ years specializing in auto loans, refinancing, and market trends |
| Education | B.A. in Journalism, University of Central Oklahoma |
| Certifications | Certified Financial Education Instructor (CFEI) |
| Expertise | Car loan interest rates, dealership financing, and debt payoff strategies |
Rebecca Betterton is a Senior Auto Finance Analyst based in New York, NY. She has 14 years of experience in consumer auto lending, loan structuring, and refinance analysis.
She spent the first eight years of her career at a regional credit union in Central New York, where she underwrote auto loan applications, built amortization models, and worked directly with members trying to understand whether refinancing made sense for their situation. She left in 2016 to start a small consultancy, where she reviewed loan documents and ran refinance scenarios for individual borrowers rather than institutions.
Today, Rebecca is the lead analyst for AutoLoanRefinanceCalculator.com. She reviews all calculator tools and educational content before publication, verifies that amortization outputs match standard loan contract math, and updates rate examples when market benchmarks move.
Her specific areas of expertise include:
- Fixed-rate amortization modeling and daily-accrual interest calculations
- Loan-to-Value (LTV) and Debt-to-Income (DTI) underwriting standards
- Breakeven analysis: calculating the precise month when refinance savings cover transaction fees
- Negative equity scenarios and cash-in refinance strategy
- Credit profile analysis for prime, near-prime, and subprime borrowers
Education & Credentials
- B.S. Finance, University of Texas at Austin, Class of 2008
- Certified Financial Services Auditor (CFSA), retired active status, credential held 2013 to 2022
- Continuing education: CFPB consumer lending guidelines, NADA vehicle valuation standards
Editorial Commitment
Rebecca reviews content on this site before it goes live. Each tool and article is checked against current amortization formulas and published lender benchmarks. Review dates are shown on each page. If you find a calculation that does not match your loan contract, the contact form goes directly to him.