MoneyMilestones
For sole traders & small business · 2025-26

Business car: chattel mortgage, lease, or cash?

How you finance a work vehicle changes what you can deduct, when, and how much GST you claw back. We compare the three options in real after-tax dollars — depreciation, the instant asset write-off and GST included.

Prototype — and business tax is complex. This is a simplified model. It excludes FBT on employee use, balancing adjustments on sale, GST adjustments and more. Treat it as a starting point and confirm everything with your accountant.
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Your business & the car

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Depreciation & GST assumptions (2025-26)

2025-26 defaults. The instant asset write-off is legislated to drop to $1,000 from 1 July 2026 unless extended — verify before relying on it.

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The comparison

Chattel mortgage is cheapest over 5 years — net cost about
$0
— $0 less than the next option, after tax and GST.
Chattel mortgage
$0
Finance lease
$0
Pay cash
$0
GST credit (buy)
$0
Net cost after tax & GST over 5 years (lower is better)
Chattel mortgage$0
Finance lease$0
Pay cash$0
The guide

Financing a work vehicle: the tax that decides it

For a business, the question isn't just "what does the car cost" — it's "what can I deduct, when, and how much GST do I get back." The three common ways to fund a work vehicle are taxed quite differently, and the gap between them can be thousands.

Chattel mortgage — you own it, you depreciate it

With a chattel mortgage the business borrows to buy the vehicle and owns it from day one. That means you can claim the GST credit up front (capped for cars), depreciate the vehicle, and deduct the interest on the loan — all apportioned to your business-use percentage. Because you own it, an eligible small business can also use the instant asset write-off — but only if the car's cost is under the threshold, which most aren't.

Finance lease — you deduct the payments

With a lease the financier owns the car and you rent it. You can't depreciate it or claim the GST credit on the purchase, but the lease payments are deductible (business portion) and you claim GST on each payment. At the end there's a residual to pay if you want to keep the car. Leasing often spreads the deduction more evenly, which can suit cash flow even when the headline cost is similar.

Cash — simple, but not free

Paying cash means no interest and you still depreciate the vehicle and claim the GST credit. The hidden cost is opportunity: the money is locked in a depreciating asset instead of working elsewhere, so the calculator counts a return on the cash you tie up.

The instant asset write-off, and the cliff. For 2025-26 an eligible small business (turnover under $10m) can instantly deduct assets under $20,000 — but most cars cost more, so they go into the small-business pool instead (15% in year one, then 30% a year), with the deductible cost capped at the $69,674 car limit. The $20,000 write-off is legislated to fall back to $1,000 from 1 July 2026 unless extended, so timing a purchase can matter. Leased vehicles can't use it at all — that's a real point of difference.

How we calculate this

  • Net cost = total cash you pay, minus the GST credits you receive, minus your tax deductions multiplied by your tax rate.
  • Chattel & cash claim depreciation (write-off or pool) plus running costs; chattel adds interest deductions, cash adds an opportunity cost on the money tied up.
  • Lease deducts the payments instead of depreciation, and adds the residual at the end.
  • Your business-use % apportions every deduction and GST credit; all three end with you owning the vehicle.

Common questions

Chattel mortgage or lease — which is better for tax?
A chattel mortgage lets you own the car, claim the GST credit up front, and deduct depreciation and interest. A lease lets you deduct the payments instead. Which wins depends on the car's price, your tax rate, your business-use percentage and cash flow — compare your own numbers above.
Can I use the instant asset write-off on a car?
Only if the car's cost is under the $20,000 limit (2025-26) and you bought it via cash or a chattel mortgage — leased vehicles don't qualify. Most cars exceed $20,000, so they're depreciated through the small-business pool, capped at the $69,674 car limit.
How much GST can I claim on a business car?
If you're registered for GST, you can claim the GST credit on the purchase (capped at $6,334 for 2025-26, being one-eleventh of the car limit) and on running costs and lease payments — all reduced to your business-use percentage.
Does business-use percentage matter?
Hugely. Depreciation, interest, lease payments, running costs and GST credits are all deductible only to the extent the vehicle is used for business. Keep a logbook — the ATO expects evidence for the percentage you claim.
What about FBT on a business car?
If a company or trust provides the car to an employee (including a director) for private use, FBT can apply — a significant cost this tool doesn't model. Sole traders don't pay FBT on their own vehicle but simply can't deduct the private-use portion. Ask your accountant which applies to you.

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