The car affordability calculator works out maximum car value and interest paid from the values you supply. Enter interest rate, loan term, money you have, monthly payment you can afford, sales tax rate, current car trade in value, and the calculator applies the standard relationship straight away, so you get the answer without working through the algebra yourself.
What Is the Car Affordability Calculator?
It is built around maximum car value, interest paid, loan amount, and it works the same way whether you are checking a homework answer, confirming a colleague's figure, or working something out for yourself. Everything runs in your browser, so nothing you enter is uploaded anywhere.
How the Car Affordability Calculation Works
The calculator works through the relationship one step at a time, so a change in any input flows straight through to the result.
The relationship between interest rate, loan term, money you have, monthly payment you can afford, sales tax rate, current car trade in value and maximum car value, interest paid, loan amount, sales tax is fixed, so the same figures always give the same answer. That makes it a good cross-check: run the numbers a second way and see whether the result agrees.
Getting a Result You Can Trust
Start with a set of figures you are confident about. If one of the interest rate or loan term or money you have or monthly payment you can afford or sales tax rate or current car trade in value values looks wrong, the result will be wrong too, because everything downstream is built on top of it. Work through the outputs one at a time and check that each one is the size you would expect before relying on the last figure.
Frequently Asked Questions
What do I need to work out maximum car value?
Enter interest rate, loan term, money you have, monthly payment you can afford, sales tax rate, current car trade in value. The calculator then works through the relationship and reports maximum car value, interest paid, loan amount.
What does the car affordability actually calculate?
It takes interest rate and loan term and money you have and monthly payment you can afford and sales tax rate and current car trade in value and converts them into maximum car value, interest paid, loan amount using the standard relationship for this problem. Each step is applied in turn, so every output is traceable back to the numbers you typed in.
How should I enter interest rate?
Use the value you actually have, in the unit shown next to the field. Enter every value in the same unit system. The calculator assumes the figures you supply are consistent, so it cannot correct a mistake that happens before the calculation starts.
Why does a small change in one value move the answer so much?
That happens when an output depends on a ratio, because dividing by a small number magnifies any change in it. Check the units first, then check whether the value you entered is in the range the relationship was designed for.
Can I use this for a quick estimate as well as a precise answer?
Yes. The calculator is built for quick checks, so round your inputs to a sensible number of significant figures and the result will be just as useful. If you need more precision, keep the same method and add digits to the inputs rather than adjusting the method itself.