Car running costs in NZ: the weekly checklist before you choose

You're down to two cars, and both finance quotes come to the same weekly repayment. One is a petrol hatchback first registered in 2018. The other is a diesel first registered in 2021.

The repayment isn't all you'll pay each week. Fuel, rego, the warrant and servicing come on top, and they depend on the car. So the two cars can cost you different amounts each week, and you can work out which costs less before you sign.

In NZ, you pay the repayment each week plus the car's running costs: fuel or charging, road user charges if it pays them, the rego, the warrant and the servicing. Work out each one for the car you're looking at, turn it into a weekly figure, and add them up before you choose.

Every fee and rule below is NZTA's, as at October 2026.

What goes on the checklist?

Six lines, and five of them apply to every car. Line 3, road user charges, is only for a diesel, electric or plug-in hybrid car.

The repayment

The weekly figure on the finance quote, with the total you'll repay beside it.

Fuel or charging

Divide your kilometres a week by 100, then multiply by the car's litres per 100 km. That's your litres a week. Multiply by the price at the pump, petrol or diesel. Drive 200 km a week in a car that uses 8 litres per 100 km, and you burn 16 litres a week. For an electric car, use its kWh per 100 km and your power price per kWh instead. A plug-in hybrid needs both sums.

Road user charges, for a diesel, electric or plug-in hybrid car

Diesel and battery electric cars pay $76 per 1,000 km. A plug-in petrol hybrid pays $38 per 1,000 km, plus the tax on its petrol. Buy a road user charges licence online and you pay a $12.44 admin fee on each one.

The rego

For a private car, 12 months' rego starting after 1 July 2026 costs $181.45 for petrol and $248.83 for diesel or electric.

The warrant

How often the car needs one depends on when it was first registered. Ask a local inspector for the price.

Servicing

Check the schedule in the owner's manual and ask your garage what it costs.

How do you work out a car's weekly running costs?

Turn every line into a weekly figure, then add them up.

• Step 1: Divide the yearly costs (rego, warrant, servicing) by 52. The rego above comes to about $3.49 a week for petrol and $4.79 for diesel or electric.

• Step 2: Work out fuel or charging, and any road user charges, from your kilometres a week.

• Step 3: Add the running costs together.

• Step 4: Write that figure next to the weekly repayment. Add the two, and that's the whole cost of the car each week.

Aren't the running costs much the same for any car?

No. The fuel type and when the car was first registered change four of the six lines.

Two petrol cars pay the same rego, and if they were first registered in the same month, they need a warrant just as often.

Switch the fuel and three lines change: what you pay at the pump or the plug, the rego, and road user charges. A diesel or electric car pays $67.38 more a year in rego than a petrol one. It also pays road user charges on every kilometre, where a petrol car pays its tax at the pump. At 200 km a week, those charges come to $15.20 a week, before the admin fee.

From 1 November 2026, a car needs a warrant every year or every two years, depending on when it was first registered.

Is it cheaper to run a diesel or a petrol car in NZ?

It depends on how far you drive and what each car burns. The diesel pays more rego, plus road user charges. The petrol car pays no road user charges, because its fuel tax is in the price at the pump.

These figures are from NZTA, as at October 2026.

Work out each car's fuel and any road user charges from your own kilometres, add its rego, and you'll see which one costs less to run.

How often will the car need a warrant from 1 November 2026?

Every two years, for most cars first registered on or after 1 November 2019. The government has announced the changes below. They start on 1 November 2026, and apply to some older cars from 1 November 2027.

• A new car: its second warrant at four years, up from three.
• Four to 14 years old: every two years, starting with cars registered on or after 1 November 2019. Cars first registered from 1 November 2013 to 31 October 2019 stay on a yearly warrant until their first one after 1 November 2027, then every two years.
• 14 to 26 years old: every year, as now.
• First registered before 1 January 2000: every year, instead of every six months.

Until 1 November 2026, a car first registered on or after 1 January 2000 needs a warrant every 12 months.

Two more questions about running costs

Do petrol cars pay road user charges?

Not today. A petrol car pays fuel tax when you buy petrol. The government plans to move all light vehicles to electronic road user charges. It hasn't set a date.

What happens if the warrant runs out?

You can only drive the car to get it repaired or inspected, and only if it's safe. The fine for a warrant more than two months out of date is set to rise from $200 to $350.

Back to your shortlist

Fill in the lines and you'll see the two cars don't cost the same. The 2021 diesel pays $67.38 more a year in rego, and road user charges on every kilometre. The 2018 petrol needs a warrant every year until its first warrant after 1 November 2027, then every two years. The diesel moves to every two years from 1 November 2026. Which one costs you less each week comes down to how far you drive and what each car burns.

A better finance adviser can give you your three numbers for the car you pick: what the loan costs each week, how long it runs, and the total you'll repay. Add the car's running costs to the weekly number before you choose.

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Disclaimer: Please note that the content provided in this article is intended as an overview and as general information only. While care is taken to ensure accuracy and reliability, the information provided is subject to continuous change and may not reflect current developments or address your situation. Before making any decisions based on the information provided in this article, please use your discretion and seek independent guidance.