Used Car Purchase Calculator
Used car purchase calculator works out Most you can finance and Vehicle price you can afford from Most you want to pay each month, Annual interest rate (APR) and Loan term. The default figures on this page give vehicle price you can afford of 20,880.10; change any entry and the result, the working and the sources update together.
Your figures
Updates as you typeHow this is worked out
5 steps
- Monthly rate r = 7% / 1200 = 0.00583333.
- Annuity factor = (1 - (1 + 0.00583333)^-48) / 0.00583333 = 41.760201.
- Most you can finance = 500 x 41.760201 = 20880.1.
- Vehicle price = 20880.1 + 0 cash and net trade - 0 financed taxes and fees = 20880.1.
- Over 48 months you would pay 24000 in all, of which 3119.9 is interest.
Its 5 worked examples are re-run on every release, last on 15 September 2026. What changed
Sources and references
4 sources
What the used car purchase calculator calculates
Turns a maximum monthly car payment, an interest rate and a loan term into the largest amount that can be financed, and the vehicle price that supports once cash down, a net trade-in and the taxes and fees rolled into the loan are included.
How to use this used car purchase calculator
Enter Most you want to pay each month, Annual interest rate (APR), Loan term and Cash down plus net trade-in. Most you can finance updates as you type. Change one figure at a time to see what drives the result.
How the result is worked out
Open “How this is worked out” beside the result for the step-by-step calculation behind Most you can finance, Vehicle price you can afford and Principal bought per 1 of monthly payment.
The method follows OpenStax, Principles of Finance 2e, section 8.3 Loan Amortization, Consumer Financial Protection Bureau, "How much can I afford to borrow for a car or auto loan?", Consumer Financial Protection Bureau, "How do I compare auto loan offers?" and Consumer Financial Protection Bureau, auto loans key terms.
What you can compare
Change one input at a time to see how it affects Most you can finance, Vehicle price you can afford and Principal bought per 1 of monthly payment. The inputs you can vary are Most you want to pay each month, Annual interest rate (APR), Loan term, Cash down plus net trade-in and Taxes, fees and add-ons rolled into the loan.
Understanding Most you can finance, Vehicle price you can afford and Principal bought per 1 of monthly payment
A planning estimate, not a credit decision. The rate and term you are actually offered depend on the lender and your credit, and ownership costs beyond the loan - insurance, fuel, maintenance, registration, tyres - are not included here.
Results are general information, not financial, tax, legal, medical or engineering advice. Check any decision that matters with a qualified professional.
See something wrong? Report a problem with this calculator
Frequently asked questions
What is the 20% rule when buying a car?
On the figures this page opens with — most you want to pay each month 500 and annual interest rate (APR) 0% — the vehicle price you can afford is 20,880.1. No single number fits everyone: change any figure above and the answer updates as you type, with each step of the arithmetic beside it.
How much is a $30,000 used car loan?
It needs Most you want to pay each month, Annual interest rate (APR), Loan term, Cash down plus net trade-in and Taxes, fees and add-ons rolled into the loan. Nothing else is required, and the figures stay in your browser.
What is the 8% rule when buying a car?
The result gives Most you can finance, Vehicle price you can afford, Principal bought per 1 of monthly payment, Monthly interest rate, Total you will pay over the term and Total interest over the term, each labelled with its unit so the figure can be read on its own.
What information do I need for the used car purchase calculator?
You need Most you want to pay each month, Annual interest rate (APR), Loan term, Cash down plus net trade-in and Taxes, fees and add-ons rolled into the loan. The page opens with default figures that give vehicle price you can afford of 20,880.10, so you can see the scale before entering your own.
What does this used car purchase calculator show?
It shows Most you can finance, Vehicle price you can afford, Principal bought per 1 of monthly payment, Monthly interest rate, Total you will pay over the term, Total interest over the term and Share of your payments that is interest, with the working and any warnings for your entries.
Can I check how the used car purchase calculator result was calculated?
Yes. The “How this is worked out” section shows the calculation steps, and the sources section identifies the references used for the method.