IRD 90-Day Logbook Rules NZ (2026–27): 3-Year Validity, Work Utes & Kilometre Rates

Short answer: Under sections DE 6 to DE 11 of the Income Tax Act 2007 and Operational Statement OS 19/04b, an IRD 90 day logbook is a continuous 90-day record of business trips and total vehicle distance used by a New Zealand sole trader to establish a vehicle’s business-use percentage for up to 3 income years. You apply that percentage to either IRD’s Tier 1/Tier 2 kilometre rates or actual vehicle costs on your IR3 (Box 24) and IR10 return. Without a logbook, deductions are capped at 25%.

⚡ Instant NZ IRD 90-Day Logbook, Kilometre Rate & IR3/IR10 Toolkit ($NZD): Calculate your NZ business vehicle deduction in the interactive NZD Mileage & Logbook Calculator right below, save your first 5 vehicle logs, Mitre 10 dockets, or NZBN tax invoices in the iCloud Web Workspace (5 Free Saves) (or click 🔗 Embed / CSV Template), explore the AU/NZ Tradie & Sole Trader App Store Edition and Business Mileage Logbook Edition, or Download Keel Free on the App Store ($0/mo) (au-nz-tradies).

Every self-employed Kiwi builder, sparky, plumber, landscaper, and contractor driving a Hilux, Ranger, van, or station wagon faces the same audit question from Inland Revenue (IRD): can you prove your business-use percentage with a compliant 90-day logbook, or are you restricted to the 25% default ceiling?

Below is the complete 2026–2027 New Zealand IRD 90-day logbook guide, including what every entry must show, how the 3-year validity window and 20% variation rule work, when a sign-written work ute qualifies for 100% business use, and how to link your logbook to your IR3 tax return, IR3B/IR10 schedule, and NZ GST returns.

Why does an IRD 90-day logbook matter so much for a NZ sole trader?

Under section DE 8 of the Income Tax Act 2007, if a sole trader uses a motor vehicle partly for business and partly for private trips and does not keep a valid 90-day logbook (or full year-round trip records), the maximum deduction you can claim is capped at 25% of the vehicle’s total running costs or kilometre-rate distance—even if you actually drove the ute 85% of the time for trade jobs!

Your Logbook Status	Maximum Business Use % You Can Claim on IR3 / IR10	Impact on a Sole Trader Driving 18,000 Total km (15,300 Business km = 85% Work Use, Diesel Ute)
Valid IRD 90-Day Logbook Kept (Proving 85% business use)	85% (Your actual proved business share for up to 3 years)	Tier 1 (14,000 × 85% = 11,900 km @ $1.30) + Tier 2 (3,400 km @ $0.38) = $16,762.00 tax deduction
No Logbook Kept (Relying on default statutory rule)	Capped at 25% maximum (s DE 8(2))	Capped at 25% of vehicle use (4,500 km) = ~$5,850.00 deduction (You lose over $10,900 in deductions!)
100% Work-Only Commercial Van / Ute (Zero private use)	100% (Must still be able to prove zero private use)	100% of actual fuel, RUC, rego, insurance, servicing & depreciation (or 100% km rates)

What must a compliant IRD 90-day logbook include in 2026–2027?

Unlike Australia (which requires a 12-week logbook valid for 5 years), New Zealand’s sections DE 7 and DE 9 of the Income Tax Act 2007 require a logbook covering at least 90 consecutive days at a time of year that represents your normal average business use, and that logbook remains valid for up to 3 years.

To pass an Inland Revenue review, your 90-day logbook must record:

1. The exact start date and end date of the 90-consecutive-day test period;
2. The vehicle’s odometer reading at the start of day 1 and at the end of day 90 (so IRD can see the total distance travelled for both business and private use during the 90 days);
3. For every business journey during the 90 days:
   • The date of the trip;
   • The distance travelled (in km) for that business trip (or start and finish odometer readings);
   • The specific reason for the trip (e.g., “Site inspection & quote at 22 Dominion Rd, Mt Eden + PlaceMakers timber pickup” — never just “Work”);
4. Annual opening and closing odometer readings (on 1 April and 31 March for a standard balance date) for each of the 3 income years the logbook is used, especially if you claim under the two-tier NZ IRD mileage rate method.

Worked Example: Calculating Your 3-Year IRD Logbook Percentage

Suppose an Auckland electrician records a 90-day logbook from 1 May to 29 July:

• Start odometer (1 May): 42,100 km
• End odometer (29 July): 46,600 km $\to$ Total 90-day distance = 4,500 km
• Total recorded business trips during the 90 days: 3,825 km
• 3-Year IRD Business-Use Percentage: $$\frac{3,825\text{ km (Business)}}{4,500\text{ km (Total)}} = 85.0%$$

For the next 3 income years, you claim 85.0% of your annual vehicle expenses (or apply 85.0% to the IRD Tier 1/Tier 2 kilometre bands) and 85.0% of the 15% GST on your vehicle running costs!

What is the IRD “20% variation rule” that forces a new 90-day logbook early?

Under section DE 7(2) of the Income Tax Act 2007, your 90-day logbook is valid for up to 36 months (3 income years), UNLESS the business proportion of your vehicle’s use changes by more than 20 percentage points (for example, dropping from 85% down to 60% because you moved house or bought a second vehicle). If your business use shifts by more than 20%, or if you replace the vehicle with a vehicle that has a different pattern of use, you must start a fresh 90-day logbook.

How does the 90-day logbook interact with IRD Kilometre Rates vs Actual Costs in 2026–27?

Under Operational Statement OS 19/04b, once you have your 90-day logbook percentage, you choose either the Kilometre Rate method or the Actual Cost method when you first start using the vehicle for business—and once chosen, you must stick with that method for as long as you own that vehicle:

Method	How the 90-Day Logbook % Is Applied (OS 19/04b)	Can You Also Claim 20% Investment Boost or Depreciation?	Best For Which Kiwi Tradie?
Method A: IRD Two-Tier Kilometre Rates (2026 rates: $1.20/km Petrol, $1.30/km Diesel, $0.90/km Hybrid, $1.22/km EV on Tier 1; then 37c / 38c / 24c / 23c on Tier 2)	Multiply the 14,000 km Tier 1 band by your logbook business % (e.g., 14,000 km × 85% = 11,900 km at Tier 1 rate); any remaining business km above 11,900 km are claimed at the Tier 2 rate	No — IRD’s Tier 1 kilometre rates already include a built-in vehicle depreciation component	High-mileage sole traders driving reliable utes/vans or second-hand vehicles where simplicity beats keeping every fuel docket
Method B: Actual Vehicle Running Costs + Depreciation	Claim your logbook business % (e.g., 85%) of every fuel, RUC (Road User Charges), WoF, rego, insurance, tyre, and servicing receipt PLUS 85% of annual depreciation	Yes! If you bought a brand-new work ute over $1,000 on/after 22 May 2025, you can claim 85% of the 20% Investment Boost upfront plus 85% of 20% DV depreciation	Tradies buying a brand-new $45k–$70k ute eligible for the 20% Investment Boost or vehicles with high RUC/repair costs

Does a sign-written dual-cab ute automatically get 100% tax deduction in NZ without a logbook?

No—this is a classic Kiwi tradie myth. Even if your dual-cab Ranger or Hilux has your business logo on the doors and toolboxes on the tray, the FBT work-related vehicle rules apply to companies paying Fringe Benefit Tax—not automatically to an unincorporated sole trader under Subpart DE!

For a sole trader, you can only claim 100% of a ute or van without a 90-day logbook if the vehicle is genuinely used 100% for business and 0% for private trips (for example, it is parked at your yard/home and you have a separate private family car used for all weekend, school, supermarket, and fishing trips). The moment you use that sole-trader ute for weekend towing or family errands, it is a mixed-use vehicle and requires a 90-day logbook to avoid the 25% cap.

Remember: under section HB 1 / Subpart DB, travel from home to a fixed yard or office is normally private, unless your home is your genuine base of business operations (where you do quotes, invoicing, and store bulky trade tools/ladders that cannot be carried on public transport) and you travel directly from home to fluctuating client jobsites.

Frequently asked questions

How long do I have to keep my 90-day vehicle logbook in New Zealand?

Under section 22 of the Tax Administration Act 1994, you must retain your 90-day logbook for 7 years after the end of the last income year to which that logbook relates. Because a 90-day logbook can be used to support your business-use percentage for up to 3 income years, you must keep that logbook record for up to 10 years from the day you recorded it (3 years of active use plus 7 years of statutory retention). See our NZ 7-year record keeping guide.

Do I need to record private trips in detail in my IRD 90-day logbook?

No. You only need to record the date, distance, and specific business reason for each business journey, plus the vehicle’s opening odometer reading on day 1 and closing odometer reading on day 90. The difference between total kilometres travelled (closing minus opening odometer) and your summed business kilometres automatically gives your private kilometres.

Can I claim 15% GST on my fuel and RUC if I use the IRD kilometre rate for income tax?

No—you cannot use the IRD income tax kilometre rates to calculate GST credits. For GST returns, a GST-registered sole trader claims 15% GST (3/23rds) on actual tax invoices/taxable supply information for fuel, RUC, tyres, servicing, and insurance multiplied by your 90-day logbook business-use percentage.

What happens if I don’t keep a 90-day logbook for my work vehicle in New Zealand?

Under section DE 8(2) of the Income Tax Act 2007, if you do not keep a valid 90-day logbook (or complete year-round trip records) for a mixed-use vehicle, Inland Revenue caps your maximum business deduction at 25% of the vehicle’s running costs or kilometre-rate distance.

When must I start a new IRD 90-day logbook before the 3 years are up?

Under section DE 7(2), you must complete a new 90-day logbook early if the business-use proportion of your vehicle changes by more than 20 percentage points (for example, dropping from 85% to 60%), or if you replace the vehicle with one that has a different pattern of business vs private travel.

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