What is the most important number when comparing car finance?

The true total cost over the period you plan to keep the car is the single most honest comparison number, because it captures interest, fees, tax effects, any balloon or residual, and the car's exit value. The monthly repayment is the most misleading number on its own, because it can be lowered by extending the term, adding a balloon, or hiding a higher price. Compare total cost first, then convert to an effective monthly cost to compare options with different term lengths.

Should I choose the finance option with the lowest interest rate?

Not necessarily. The lowest headline rate can still be the most expensive option once fees are included, which is why the comparison rate is a fairer number. Beyond that, the lowest-cost option overall depends on tax treatment (for business use or a salary-packaged novated lease), opportunity cost (for paying cash), and any balloon or residual. The right choice is the one with the lowest true total cost for your situation, not the lowest rate.

How do I compare a novated lease against a car loan fairly?

Put both on the same basis: total cost over the same hold period, after tax. A novated lease bundles running costs and reduces taxable income, so you must include the income tax saving, any FBT or post-tax contribution, and the residual owing at the end. A personal loan does not affect tax for private use, so its cost is the deposit, repayments, and interest, less the car's resale value. A calculator that models both structures with your salary and vehicle removes the guesswork.

Guide Car Finance Updated June 2026 · 10 min read

How to Make an Informed Decision on Car Finance

Choosing car finance is not really about picking a product — it is about comparing options on the same terms and matching the result to your situation. Most poor decisions come from comparing the wrong number (the monthly repayment), ignoring tax or opportunity cost, or being nudged by a sales process. This guide gives you a clear framework: the numbers that matter, the questions to ask, the traps to avoid, and how to reach a decision you can defend.

In this guide

1. Start with your goals, not the products
2. The five numbers that actually decide it
3. Don't forget tax and opportunity cost
4. The behavioural traps to avoid
5. Questions to ask before signing
6. A simple decision process
7. A worked comparison

1. Start with your goals, not the products

Before comparing any finance, get clear on what you are optimising for. People weigh these differently, and the "best" option changes depending on which matters most to you:

Lowest total cost over the time you will own the car.
Lowest monthly outflow, even if it costs more overall (cash-flow priority).
Lowest upfront cash required on day one.
Owning the car outright versus minimising commitment.
Tax efficiency, if you are an employee who can salary-package or a business.

If you are not honest about your priority, you will be pulled toward whichever number a salesperson chooses to highlight. Decide your priority first; then the numbers can rank the options against it.

2. The five numbers that actually decide it

Whatever the product, compare these five figures across every option on a like-for-like basis:

Number	What it tells you
True total cost	The most honest single figure — all repayments, fees, interest, tax effects, balloon/residual, minus the car's exit value, over your hold period.
Effective monthly cost	True total cost divided by the months you will own the car. Lets you compare options with different term lengths fairly.
Upfront cost	Cash needed on day one — deposit plus stamp duty. Matters if liquidity is tight.
Monthly payment	The finance repayment only. Useful for cash flow, misleading as a comparison of total cost.
Total interest / exit value	How much you pay to borrow, and what the car is worth when you are done. Both swing the total cost.

The monthly payment is the trap, not the answer

Almost any monthly figure can be made to look affordable by stretching the term or adding a balloon — while quietly increasing what you pay in total. Always settle the total cost first, then look at the monthly figure to check it fits your cash flow.

3. Don't forget tax and opportunity cost

Two factors are routinely left out of back-of-envelope comparisons, and both can flip the answer:

Tax. For a novated lease, pre-tax salary deductions reduce your taxable income, and an eligible EV may be exempt from FBT — so a novated lease can beat a personal loan even at a higher nominal rate. For business use, a chattel mortgage can allow interest and depreciation claims. For private use of a personal loan, there is no tax effect.
Opportunity cost. Paying cash uses money that could otherwise earn a return or offset mortgage interest. A fair comparison prices that in — our cash vs finance guide shows how.

Leaving these out makes simple options look better than they are and tax-effective options look worse. Any honest comparison has to include them.

4. The behavioural traps to avoid

Anchoring on the monthly figure. Covered above — the most common and most expensive trap.
Blending the trade-in. Merging your trade-in into the finance hides whether you got a fair price for either. Negotiate them separately.
Add-ons sold as "included". Paint protection, extended warranties, and insurance products bundled into finance accrue interest and are rarely worth the financed cost. Decide on each separately.
Rate without comparison rate. A low headline rate with high fees can be the dearer loan — see what is a comparison rate.
Balloon blindness. A balloon lowers the monthly cost but leaves a lump sum to refinance or pay later — see balloon payments explained.
Deciding under time pressure. "This price is only today" is a sales tactic. A genuinely good deal survives a night's sleep.

Compare on true total cost

Let the numbers rank your options

Enter your vehicle, salary, deposit, and hold period. Veercal calculates the true total cost, effective monthly cost, upfront, interest, and exit value for cash, personal loan, dealer finance, lease, and novated lease — ranked cheapest to dearest, with the tax effects built in.

Open the calculator →

5. Questions to ask before signing

Whoever you are dealing with, the answers to these should be clear and in writing:

What is the comparison rate, and what fees are and are not included in it?
What is the total amount payable over the full term?
Is there a balloon or residual, and how much will be owing at the end?
What are the fees — establishment, monthly account, early termination?
Can I repay early without penalty, and what happens if I sell the car mid-term?
Is the loan secured against the car, and what happens if I default?
For a novated lease: what is the residual, is the vehicle FBT-exempt, and what is included in the running-cost budget?

6. A simple decision process

Set your priority (lowest total cost, lowest monthly, owning outright, tax efficiency).
Fix the vehicle and hold period so every option is compared on the same car for the same time.
Model each realistic option on true total cost, including tax and opportunity cost.
Sanity-check the monthly against your actual budget, with running costs included.
Read the contract for fees, balloon, early-exit, and security terms before committing.
Sleep on it. A sound decision does not require signing today.

7. A worked comparison

The point of a worked example is not the exact figures — yours will differ — but the method: comparing total cost rather than the monthly repayment, and including tax. Below, two options for the same car over the same period are compared on what each truly costs after tax and resale. The headline monthly figure favours one; the true total cost can favour the other.

Illustrative — same car, same hold period, two structures

Option A — lowest monthly repaymentlooks cheapest monthly

Option B — higher monthly, tax-effectivehigher monthly

But after income tax saving, FBT/contribution, and resale…Option B lower total cost

Decision drivertrue total cost, not the monthly

This is exactly the comparison a calculator is built for, because doing it by hand across five structures with tax effects is error-prone. Our companion guide how to read the Veercal calculator results walks through interpreting the output once you have run your own numbers, and the guide to car finance explains each product in depth.

General information only — not financial advice. This guide describes a general decision-making approach and does not account for your personal circumstances. Worked figures are illustrative only. Tax treatment depends on current ATO rules and your situation. Before making a finance decision, consider seeking advice from a licensed financial adviser, credit provider, or accountant. Full disclaimer.