Fuel Tax Breakdown Calculator NZ

This calculator breaks down the price you pay for petrol at the pump, showing how much is tax and how much is the actual cost of the fuel. New Zealand petrol prices carry a surprisingly large tax component, and most drivers have no idea what share of each litre goes to the government rather than to the fuel itself. The taxes include fuel excise duty, the largest single component, an ACC levy that funds accident cover, an emissions trading charge, and then GST charged on top of the whole lot, including on the other taxes. Together these can make up close to half the pump price. This tool reveals the split. You enter the pump price per litre and the total fuel taxes and levies per litre excluding GST, which is pre-filled with a typical figure you can adjust, and the calculator works out the GST component, the total tax, the underlying cost of the fuel before tax, and the percentage of the pump price that is tax. The results update as you type. Use it to understand where your fuel money goes, to see the effect of excise and levy changes, or simply out of interest. The GST is calculated as three twenty-thirds of the GST-inclusive pump price, the standard way to extract 15 percent GST from a tax-inclusive amount, and the excise and levies are taken as a fixed number of cents per litre. The before-tax cost is what is left, the commodity price of the fuel plus the retailer's margin. A striking insight the calculator gives: because GST applies on top of the excise and levies, you effectively pay tax on tax, and the combined tax share of a litre of petrol is often around 45 to 50 percent. The exact excise and levy rates change over time and with government policy, so adjust the input to match the current figures.

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$1.37
total tax per litre
GST component$0.37
Excise & levies$1.00
Fuel cost before tax$1.43

GST = price x 3/23. Excise and levies are a fixed cents-per-litre amount you can adjust. GST applies on top of the levies, so you pay tax on tax. Rates change over time.

How it works

The GST in the pump price is three twenty-thirds of the price, the standard way to find 15 percent GST within a tax-inclusive amount. The excise and levies are the cents-per-litre figure you enter. Total tax is the GST plus the levies, and the cost of the fuel before tax is the pump price minus that total tax.

Worked example

At a pump price of $2.80 a litre with $1.00 of excise and levies, the GST is $2.80 times 3 over 23, about $0.37. The total tax is $0.37 plus $1.00, which is $1.37, nearly half the price. The underlying fuel cost before tax is $2.80 minus $1.37, about $1.43 per litre.

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Data sources: the rates and thresholds on this page are maintained against Inland Revenue. Figures are checked twice monthly.

Frequently asked questions

How much of the petrol price is tax?

Often close to half. The price includes fuel excise duty, an ACC levy, an emissions charge and then GST on top of all of it. This calculator splits the pump price into the GST, the excise and levies, and the underlying fuel cost so you can see the share that is tax.

Is GST charged on the fuel excise?

Yes. GST is applied to the full pump price, which already includes the excise and levies, so you effectively pay tax on tax. The calculator extracts the GST as three twenty-thirds of the pump price, capturing this effect.

Why are the excise and levy figures editable?

Because they change over time with government policy and ACC levy reviews. The calculator pre-fills a typical total but lets you adjust it to the current cents-per-litre figure so your breakdown reflects today's rates rather than an out-of-date number.