Cents Per Km vs Logbook 2026: Which Tax Method Refunds You Most?
ATO 88c/km capped at $4,400 — but high-mileage drivers get more from the logbook method. Compare both for 2025-26 with real worked examples.
How One Decision Could Add Thousands to Your 2026 Tax Refund
Every year, hundreds of thousands of Australians leave money on the table at tax time by picking the wrong method to claim their car expenses. The ATO offers two main paths: the **cents per kilometre method** (simple, capped) and the **logbook method** (detailed, uncapped). For the **2025-26 financial year**, the cents per km rate stays at **88 cents per business kilometre**, with a cap of 5,000 km — meaning the maximum claim is **$4,400 per car**.
That sounds straightforward. The catch: if you drive more than 5,000 business kilometres a year, that cap is silently costing you. A tradie doing 8,000 business km in a thirsty ute could legitimately claim **$7,000–$8,000** under the logbook method, but only **$4,400** if they take the easy road. That's a **$3,000+ refund difference** — every single year.
On the other hand, if you only drive 3,000 business km a year as a part-time consultant, doing a 12-week logbook is a colossal admin overhead for maybe $200 in extra deduction. The right answer depends entirely on your kilometres, your car, and how much paperwork you can stomach.
This guide breaks down both methods using current 2025-26 ATO rules, runs two real-world worked examples (low-km vs high-km drivers), shows you the break-even point, and finishes with a compliance checklist so the ATO can't claw the deduction back.
Method 1: The Cents Per Kilometre Method (88c/km in 2025-26)
The cents per kilometre method is the ATO's simplified path for low-mileage drivers. You multiply your business kilometres by a fixed rate, and that's your deduction. No fuel receipts. No servicing invoices. No depreciation calculations. Just kilometres × rate.
**The 2025-26 rate is 88 cents per kilometre**, applied to business kilometres only. The same rate applied in 2024-25 — the ATO held it steady despite high fuel prices. The rate is reviewed annually and is meant to bundle every running cost (fuel, servicing, registration, insurance, tyres, depreciation) into a single per-km figure.
**The cap is brutal: 5,000 business kilometres per car per year.** At 88c/km, that's a **maximum claim of $4,400 per car**. If you drive 7,000 business km, you can still only claim 5,000 × 88c = $4,400. The extra 2,000 km is invisible to the ATO under this method.
Who can use it: **sole traders** and **partnerships** (where at least one partner is an individual), and **employees** claiming work-related car expenses on their personal return. Companies and trusts can't — they have to use the actual cost or logbook method.
Although you don't need receipts under cents per km, the ATO does expect you to show **how** you calculated your business kilometres. That means a diary, calendar entries, route logs, or app data demonstrating the trips were genuinely business-related. *"I think I did about 4,500 km"* written in pen the night before lodging is exactly the kind of estimate the ATO flags. A real-time log of trip dates, destinations and purposes is what gets you through a desk audit unscathed.
One more catch: the cents per km method is for **cars only** — generally vehicles designed to carry passengers and a load of less than one tonne. Utes, vans and trucks designed to carry more than one tonne or more than nine passengers fall outside this method and have to use the actual cost approach.
Method 2: The Logbook Method (No Cap, More Paperwork)
The logbook method is the heavyweight option. It lets you claim a **percentage of every running cost** — fuel, servicing, registration, insurance, interest on a car loan, and depreciation — based on how much of your driving is for work. There's **no kilometre cap**, which is why high-mileage drivers nearly always come out ahead.
It works in two steps. First, you run a **continuous 12-week logbook** that captures your usual driving pattern. From this, you calculate your **business-use percentage**. Second, you apply that percentage to your **actual annual car expenses** — every receipt, plus depreciation.
Example: if you drive 12,000 km in 12 weeks and 8,000 of those are business, your business-use percentage is **66.67%**. You then apply 66.67% to your full year's running costs and depreciation.
Every trip in the 12-week log needs the **date**, **start and end odometer readings** (or kilometres travelled), and the **reason for the journey** (e.g., "client meeting — Smith & Co, Parramatta"). On top of that, you need odometer readings at the start and end of the 12-week logbook period, and at the start and end of every financial year you reuse the percentage.
**Validity is the lifesaver.** A completed logbook lasts **five financial years**, provided your driving pattern doesn't change materially. If you change jobs, move house, or buy a new vehicle, you'll need a fresh 12-week log. Most sole traders run one logbook every five years and reuse the resulting percentage — that's how the admin gets manageable.
When you apply your business-use percentage, you can claim fuel and oil, servicing, repairs and tyres, registration and CTP, comprehensive insurance, interest on a car loan, and depreciation up to the 2025-26 **car cost limit of $69,674**.
That car cost limit catches a lot of small-business owners. If you bought a $90,000 SUV, you can only depreciate the first $69,674. The excess is invisible to the ATO. The limit is set by the ATO each year and indexed to motor vehicle CPI.
Receipts are non-negotiable. Every fuel docket, every service invoice, every registration renewal, every insurance receipt. Bank statement entries help but aren't always enough on their own.
Cents Per Km vs Logbook: Side by Side
Quick reference comparing the two methods on the criteria that matter most:
| Feature | Cents Per Km (88c) | Logbook Method | |---|---|---| | Maximum km claimable | 5,000 business km | Unlimited | | Maximum deduction | $4,400 per car | No cap | | Receipts required? | No (just km evidence) | Yes (every expense) | | Time commitment | Low (track km only) | High (12-week log + receipts) | | Validity period | Annual (per FY) | 5 years (if usage stable) | | Depreciation included? | Bundled in the rate | Yes, up to $69,674 limit | | Best for | Under 5,000 business km/year | Over 5,000 business km/year | | Eligibility | Sole traders, partnerships, employees | All taxpayers (incl. companies & trusts) |
Both methods only apply to passenger cars. Utes and vans designed to carry more than one tonne, or vehicles carrying more than nine passengers, must use the actual cost method regardless of kilometres.
Worked Example 1: The 4,000 km Consultant (Cents Per Km Wins)
Maya is a freelance marketing consultant in Brisbane. She drives a 5-year-old Mazda3 for client meetings. Here's her year:
- **Total kilometres driven:** 14,000 - **Business kilometres:** 4,000 (28.6% business use) - **Annual running costs (full vehicle):** fuel $2,500, insurance $980, rego/CTP $850, servicing $700, depreciation ~$2,200 = **$7,230 total**
**Cents per km method:** 4,000 km × $0.88 = **$3,520 deduction**
**Logbook method:** 28.6% × $7,230 = **$2,068 deduction**
Maya's choice: cents per km wins by **$1,452**. Even with a fully detailed logbook, the small business-use percentage means the actual cost share is lower than the per-km bundled rate. Add to that 12 weeks of trip logging and a year of fuel-receipt hoarding, and the cents per km method is clearly the better trade.
**Lesson:** when business kilometres are well under 5,000 and your share of total driving is low, cents per km usually beats logbook — *and* saves you hours of admin.
Worked Example 2: The 15,000 km Tradie (Logbook Wins By a Mile)
Jake is a self-employed plumber in western Sydney running a 2024 Toyota HiLux dual-cab he financed for $52,000. Here's his year:
- **Total kilometres driven:** 20,000 - **Business kilometres:** 15,000 (75% business use, verified via 12-week logbook) - **Annual running costs (full vehicle):** - Fuel (diesel, 11 L/100km × 20,000 km × $1.95): **$4,290** - Servicing & repairs: **$1,800** - Tyres: **$1,200** - Registration & CTP: **$1,170** - Comprehensive insurance: **$1,650** - Interest on car loan: **$2,400** - Depreciation (25% diminishing value, $52,000 base): **~$8,750** - **Total annual running cost: $21,260**
**Cents per km method:** capped at 5,000 km × $0.88 = **$4,400 deduction** (the other 10,000 business km are invisible)
**Logbook method:** 75% × $21,260 = **$15,945 deduction**
Jake's choice: logbook wins by **$11,545** — more than triple the cents per km claim. The combination of high business-use percentage, expensive vehicle (close to the $69,674 car cost limit), high fuel burn and finance interest stacks the deck heavily in favour of the logbook method.
**Lesson:** the minute you cross **5,000 business km**, the cents per km cap starts costing you real money. For tradies, sales reps, real-estate agents, mobile health workers and anyone whose car is essentially a mobile office, the 12-week logbook pays for itself many times over.
The Break-Even Point: When Does Logbook Take Over?
There's no single magic number — the break-even depends on your **business-use percentage** and your **total running costs** — but a useful rule of thumb is this: the logbook method generally beats cents per km when both of these are true.
First, you drive **more than 5,000 business kilometres per year**. The moment you cross the cap, every extra km is free deduction under logbook. Second, your **business-use percentage** applied to your annual running costs gives a higher number than $4,400.
If your annual running costs (including depreciation) are around $9,000 — close to the Australian average for a mid-size sedan — you only need a **49% business-use percentage** to clear $4,400 under logbook. For a thirstier ute or SUV running closer to $15,000–$20,000 a year, even **30% business use** is enough.
Quick break-even check: take your annual running costs (including depreciation), multiply by your estimated business-use percentage. If the result is meaningfully more than **$4,400**, the logbook method is worth the admin.
Where logbook makes the biggest difference:
- **High-mileage drivers** (over 8,000 business km) - **Drivers of newer or expensive vehicles** (high depreciation) - **Drivers with fuel-hungry vehicles** (utes, SUVs, performance cars) - **Drivers with car loans** — loan interest is claimable under logbook only - **Sole traders and small-business owners** using one vehicle for both work and personal trips
Staying ATO-Compliant: Records You Need to Keep
Both methods require evidence — they just need different evidence. Get this wrong and the ATO can claw back the deduction plus interest, and in some cases penalties.
**For cents per km, you need** a diary, calendar or app showing how you calculated your business kilometres, notes on the purpose of each trip (e.g., "site visit — 47 Smith St Penrith"), odometer readings if you want extra defensibility, and records kept for **5 years** from when you lodged the return.
**For logbook, you need** a 12-week continuous log with date, destination, purpose and km for every trip; odometer readings at the start and end of the 12-week period; odometer readings at the start and end of every financial year you reuse the percentage; receipts for every expense claimed (fuel, servicing, rego, insurance, repairs, finance interest); depreciation working papers; and records kept for **5 years** from when you lodged the return.
Common ATO red flags to know about: a claim that's **exactly 5,000 km** with no supporting evidence — it's the most-claimed round number in Australia and the ATO data-matches it heavily. Business-use percentages that look round (90%, 80%) without granular trip evidence. Claims that include the daily commute between home and a regular workplace. Logbooks that were clearly written from memory in a single session — different ink, identical handwriting style, no daily variation. Fuel receipts that don't line up with the logbook kilometres.
The simplest defence: track every business trip in real time using an app, and keep digital scans of every receipt as you go. Reconciling 11 months later from a shoebox is what gets people in trouble.
5 Tax Mistakes Australian Drivers Make Every Year
**1. Claiming the home-to-work commute.** This is the #1 ATO target. Travel from home to your regular place of work is private — full stop — even if you check emails on the way. The narrow exceptions (carrying bulky tools, travelling between two workplaces, working from a home office) are scrutinised.
**2. Estimating kilometres at tax time.** *"I drive about 100 km a week for work"* pulled from memory in July is not evidence. The ATO can ask you to prove every kilometre. Use [FuelCalc's trip calculator](/){:target="_blank"} or a logbook app to capture trips as they happen.
**3. Claiming for two methods on the same car.** You can't mix cents per km and logbook on the same vehicle in the same year. Pick one method per car, per year — the ATO will reject a hybrid claim.
**4. Forgetting depreciation under logbook.** Many drivers track fuel and servicing but forget the biggest tax deduction available — depreciation. On a $40,000 car under the diminishing value method, that's typically $8,000–$10,000 of deduction in year one (× business-use %). Missing it is leaving thousands on the table.
**5. Not refreshing the logbook after a major change.** Bought a new car? Changed jobs? Moved further from clients? The five-year logbook validity assumes your driving pattern is stable. The moment something material changes, you need a new 12-week log.
Choosing the Right Method for Your 2026 Tax Return
**Cents per km is the right call** if you drive under 5,000 business km a year, your business-use percentage is low (under 40%), you'd rather not chase receipts for 12 months, and your maximum possible claim is around $4,400 anyway.
**Logbook is the right call** if you drive more than 5,000 business km a year, your business-use percentage is high (over 40%), you drive an expensive, fuel-hungry, or recently-purchased vehicle, or you're a sole trader, tradie, sales rep or anyone whose car is a working tool.
**Either way, start tracking now.** The single biggest mistake we see is drivers who decide which method to use in early July, then realise they have neither evidence nor a logbook. Use [FuelCalc's trip calculator](/){:target="_blank"} to log every business trip with distance, destination and date — the data exports into an ATO-friendly format and gives you a hard kilometre figure that survives audit. Pair it with digital receipts (photographed and stored monthly), and your 2026 tax return takes 30 minutes instead of three weekends.
The Bottom Line
The right method can put **$1,500 to $11,000+** more in your pocket every July. That's not a marginal difference — it's the difference between a paid family holiday and writing the same cheque to the ATO.
For 2025-26 the rate stays at **88c/km**, the cap stays at **5,000 business km**, and the maximum cents-per-km claim stays at **$4,400 per car**. Below 5,000 business km, take the simple option. Above 5,000 business km, run the 12-week logbook — you'll never regret the admin.
Pick deliberately. Document constantly. Lodge with confidence.
*This article is general information only and not personal tax advice. Speak to a registered tax agent for advice specific to your circumstances.*
Tags: tax deductions, cents per kilometre, logbook method, ATO 2026, sole trader tax, car expenses, work-related deductions, vehicle deductions, 88 cents per km, 5000 km cap, tax return 2026, Australia tax