New Zealand plans to move petrol cars off fuel excise duty and onto road user charges (RUC). This calculator estimates what you would pay under each system: your current excise (about 70c per litre of petrol) versus future RUC charged by distance (default $76 per 1,000 km).
Enter how far you drive and how thirsty your car is to see whether the switch would cost you more or less per year.
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Updated June 2026
Current light RUC rate $76 per 1,000 km. Petrol excise about 70c per litre. No firm switch-over date set.
1. Your Driving
km/yr
L/100km
2. Tax Rates
$
$
The RUC rate is editable because the final petrol rate and switch-over date are not yet set. The $76 default is the current light vehicle rate. Petrol excise is about 70c per litre today.
Current Excise vs Future RUC
Current Annual Excise
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Paid at the pump today
Future Annual RUC
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Charged by distance
Difference
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More or less per year
Excise vs RUC at Different Distances
Annual km
Litres/year
Current Excise
Future RUC
Difference
Current System (Petrol Excise)
Annual distance-
Fuel economy-
Litres used per year-
Excise rate-
Annual excise paid-
Future System (RUC)
Annual distance-
RUC rate-
Thousands of km-
RUC per year-
Change vs excise-
Summary:Enter your details above.
Important: Petrol cars do not pay RUC yet. The government has announced plans to move all light vehicles to RUC and remove petrol excise duty, with the new electronic system expected to begin opening around 2027, but no firm switch-over date or final petrol rate has been set. The $76 per 1,000 km figure is the current light vehicle RUC rate and is editable, so you can model whatever rate applies when the change reaches your car. This is a general estimate, not tax or financial advice.
What Is the Petrol to RUC Transition?
New Zealand currently funds its roads in two ways. Diesel and electric vehicles pay road user charges (RUC), bought as distance in 1,000 km blocks. Petrol vehicles pay through fuel excise duty, a tax of roughly 70 cents per litre included in the price you pay at the pump. The government has announced its intention to move every light vehicle, including petrol cars, onto RUC and to remove petrol excise duty altogether. The aim is a single, fairer, distance-based system supported by new electronic technology.
This calculator helps petrol-car owners see the likely effect of that change on their own road tax. It works out what you pay now in excise, what you would pay under RUC, and the difference between the two.
How the Calculation Works
The two systems charge on completely different bases, which is why the same driver can pay quite different amounts:
Current excise = litres of petrol used per year x excise per litre. Litres per year = (annual km / 100) x your fuel economy in L/100km.
Future RUC = (annual km / 1,000) x the RUC rate.
Difference = future RUC minus current excise. A positive number means RUC costs you more; a negative number means RUC costs you less.
Because RUC charges purely by distance, it ignores how fuel-efficient your car is. Excise charges by fuel burned, so a thirsty car pays more excise per kilometre. This is the key reason efficient cars often pay more under RUC, while gas-guzzlers often pay less.
Worked Example
Take the default settings: 11,500 km a year (about the NZ average), fuel economy of 8 L/100km, a RUC rate of $76 per 1,000 km, and petrol excise of 70 cents per litre.
Step
Working
Result
Litres of petrol per year
(11,500 / 100) x 8
920 L
Current annual excise
920 x $0.70
$644.00
Future annual RUC
(11,500 / 1,000) x $76
$874.00
Difference
$874.00 - $644.00
$230.00 more
In this example, moving to RUC would cost about $230 more a year. That reflects a fairly efficient car: at 8 L/100km, excise stays low. A thirstier car using more than about 10.9 L/100km would instead pay less under RUC.
The Break-Even Point
RUC and excise cost the same when your fuel economy equals the RUC rate divided by ten times the excise per litre. With a $76 rate and 70c excise, the break-even fuel economy is $76 / (10 x $0.70) = about 10.9 L/100km. If your car uses less petrol than that per 100 km, expect to pay more under RUC. If it uses more, expect to pay less. The break-even point changes if the final petrol RUC rate differs from $76, which is why the rate is editable.
When Will This Happen?
No firm date has been set. The government has signalled that the new electronic RUC system is expected to begin opening around 2027, with light vehicles transitioning over time and petrol excise eventually removed. The Road User Charges legislation is being amended to allow private providers to collect and administer RUC, which is intended to make the system more user-friendly. Pricing and the exact rollout for petrol vehicles have not been finalised. Until the change reaches your vehicle, you keep paying excise at the pump exactly as you do now.
Will I Be Better or Worse Off?
It depends entirely on your car and your driving:
Efficient cars (hybrids, small petrol cars): likely to pay more under RUC, because they use little petrol and so currently pay little excise.
Thirsty cars (large SUVs, older vehicles, V8s): likely to pay less under RUC, because their high fuel use means high excise today.
High-distance drivers: the gap grows with distance, so the effect (whichever way it falls) is bigger.
Remember that RUC replaces excise; it is not charged on top of it. Once your vehicle moves to RUC, the excise component disappears from the petrol you buy, so you are not double-paying.
Related Calculators
RUC Calculator: road user charges for EV, diesel and PHEV.
Sources: Beehive, next steps on moving to electronic road user charges (beehive.govt.nz). Ministry of Transport, Transitioning All Vehicles to Road User Charges FAQs (transport.govt.nz). NZTA Waka Kotahi RUC rates (nzta.govt.nz/vehicles/road-user-charges/ruc-rates-and-transaction-fees).
This calculator provides indicative estimates only. The transition of petrol vehicles to RUC has been announced but not finalised, and no firm switch-over date or final petrol rate is set. Petrol excise is approximate (about 70c per litre) and varies with policy. Actual costs depend on your specific vehicle and driving. Check official sources for the latest detail. Not tax or financial advice.
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