How Much Is Petrol When Oil Is $100 a Barrel?

Every time the nightly news runs a segment about oil prices spiking , OPEC cutting production, a Middle East flare-up, a Russian export ban , the natural follow-up question for most Australians is the same: what does this mean at the bowser? If crude oil hits $100 a barrel, how much will I be paying when I fill up?

It's a completely reasonable thing to wonder. Crude oil and petrol prices are obviously connected. But the relationship is not as direct as most people assume, and understanding what actually sits between a barrel of crude and your car's tank makes the whole picture a lot clearer , including why your petrol price sometimes doesn't seem to move when oil prices do, or moves more than you'd expect when they do.

This guide works through the full picture: what oil barrels have to do with what you pay at the servo, what the rough price expectation is when crude sits at $100 USD, and all the other factors that shape what you actually see on the bowser sign.

What a Barrel of Oil Actually Is

Before anything else, let's establish what we're talking about. A barrel of crude oil in the commodity market is a standardised unit of measurement , 42 US gallons, or approximately 159 litres. When news reports say crude oil is '$100 a barrel', they're referring to this volume of unrefined crude oil traded on international commodity markets.

The two most commonly referenced benchmarks are:

•       West Texas Intermediate (WTI) , the US benchmark crude, traded on the New York Mercantile Exchange. When American media reports the oil price, this is usually what they're referring to

•       Brent Crude , the international benchmark, refined from North Sea oil fields. This is more relevant to Australian petrol pricing because Australia's imported crude and refined product pricing follows international benchmarks closer to Brent

The prices of WTI and Brent generally track each other closely but can diverge based on logistics, geopolitics, and regional supply conditions. For Australian petrol pricing purposes, Brent Crude and Singapore Mogas (the Asian refined petrol benchmark) are the more directly relevant references.

From a Barrel of Crude to Your Car: The Full Journey

Crude oil doesn't come out of the ground and go straight into your tank. It goes through a complex chain of processing, transport, trading, and taxation before it reaches the bowser. Each step adds cost.

Step 1: Crude Oil Extraction and Trading

Crude oil is extracted from oil fields around the world , Saudi Arabia, the United States, Russia, Iraq, UAE, and many others. It's traded on commodity exchanges, with prices driven by global supply and demand, geopolitical events, OPEC decisions, currency movements, and market speculation.

Step 2: Shipping to Refineries

Crude oil is transported by supertanker to refineries. Australia imports a significant proportion of its refined petrol products , the country has limited domestic refining capacity following the closure of most Australian refineries between 2012 and 2021. The Ampol (formerly Caltex) Lytton refinery in Brisbane and the Viva Energy (Shell) refinery in Geelong are the only two remaining significant domestic refineries.

Step 3: Refining

The refining process separates crude oil into its component fractions: petrol (gasoline), diesel, jet fuel, LPG, lubricants, heavy fuel oil, and other products. This process consumes energy, requires sophisticated equipment, and adds a refining margin to the cost of the product.

Refining typically accounts for approximately 10–20 cents per litre of the final petrol price, though this varies with energy costs, the complexity of the refining process, and the crude oil type being processed.

Step 4: Transport and Storage

Refined petrol is transported from refineries or import terminals to fuel depots, then by tanker truck to individual service stations. These logistics costs vary by distance , servos in remote areas face higher transport costs than those in major cities, which is one of the reasons regional petrol prices are consistently higher than metro prices.

Step 5: Government Taxes and Levies

This is one of the largest components of the retail petrol price in Australia, and it's one that many people underestimate. The current components include:

•       Excise duty , the federal government levies excise on petrol and diesel. As of mid-2025, the rate is approximately 50 cents per litre (having been temporarily halved in 2022 before restoring). This is a flat per-litre charge unrelated to crude oil price

•       GST , 10% Goods and Services Tax is applied to the total price including excise, adding roughly 18–22 cents per litre at typical price levels

•       Carbon-related costs , various levies and compliance costs related to emissions policy

In total, taxes and levies typically account for 35–45% of the retail petrol price in Australia , often more than the crude oil cost itself at lower oil price environments.

Step 6: Retail Margin

The service station adds its own margin to cover operating costs and profit. Average retail margins in Australia are relatively thin , typically 3–8 cents per litre for a mainstream petrol station, though this varies significantly.

So What Does $100 USD Per Barrel Mean at the Bowser?

Now for the number you actually want. Here's how to roughly convert a $100 USD barrel of Brent Crude to an expected Australian retail petrol price.

Step 1: Convert the Barrel Price to Litres

A barrel is approximately 159 litres of crude oil. However, not all crude oil becomes petrol , the refinery yield for petrol from a barrel of crude is typically around 40–45%. So from 159 litres of crude:

•       Roughly 65–70 litres of petrol product per barrel, accounting for refinery yield

•       $100 USD divided by approximately 67 litres of petrol yield = approximately USD $1.49 per litre of crude cost allocated to petrol

Step 2: Convert USD to AUD

Oil is priced in US dollars globally. The AUD/USD exchange rate is critical to Australian petrol pricing. When the Australian dollar is weak against the USD, Australian petrol prices are higher for the same USD oil price.

•       At AUD/USD 0.65 (weak AUD): USD $1.49 per litre = approximately AUD $2.29 crude cost

•       At AUD/USD 0.70 (moderate AUD): USD $1.49 per litre = approximately AUD $2.13 crude cost

•       At AUD/USD 0.75 (stronger AUD): USD $1.49 per litre = approximately AUD $1.99 crude cost

This is why two periods with identical USD crude oil prices can produce very different petrol prices in Australia , the exchange rate does heavy lifting.

Step 3: Add Refining Margin and Transport

Typically 12–20 cents per litre combined for refining margin and distribution/logistics costs.

Step 4: Add Government Excise and GST

Approximately 50 cents per litre excise plus 10% GST on the total = roughly 68–72 cents per litre in total government impost at typical retail price levels.

Step 5: Add Retail Margin

Approximately 5–8 cents per litre.

The Result: Estimated Retail Price at $100 Oil

AUD/USD Rate	Crude Cost (per litre, AUD)	Estimated Retail Petrol Price
0.60 (weak AUD)	~$2.48	~$2.20–$2.40 per litre
0.65 (moderate-weak)	~$2.29	~$2.05–$2.25 per litre
0.70 (moderate)	~$2.13	~$1.90–$2.10 per litre
0.75 (moderate-strong)	~$1.99	~$1.75–$1.95 per litre
0.80 (strong AUD)	~$1.86	~$1.65–$1.85 per litre

Important disclaimer: these are approximations. Real petrol prices are also affected by Singapore Mogas benchmark pricing (the Asian refined petrol market), local supply and demand dynamics, competition between bowsers, state-based fuel levies, and the weekly price cycle that operates in major Australian cities. Use these figures as a rough guide, not a precise calculator.

What History Tells Us About $100 Oil and Australian Petrol Prices

Looking at historical periods when crude oil traded near $100 USD per barrel gives us real data to work with , not just theoretical calculations.

2011–2014: The Long $100 Era

Brent Crude traded above or near $100 USD per barrel for most of the period from 2011 to mid-2014 , a sustained high-price environment unprecedented in its duration. During this period:

•       Australian capital city average retail petrol prices ranged from approximately $1.35 to $1.65 per litre for 91 unleaded

•       The AUD was notably strong during this period , often above USD 0.90 and even briefly touching parity , which significantly cushioned Australian petrol prices from the full impact of $100 crude

•       Regional and remote Australian petrol prices were higher, sometimes exceeding $1.80 per litre in remote areas

The strong Australian dollar of this era is a crucial part of why Australian petrol prices in the early 2010s weren't dramatically higher despite sustained triple-digit oil. The exchange rate buffered the impact.

2022: The Spike to $120+

Following Russia's invasion of Ukraine in early 2022, Brent Crude spiked to over $120 USD per barrel. This coincided with a weaker AUD (around 0.68–0.72 range) and drove Australian petrol prices to record levels:

•       Capital city average petrol prices peaked at $2.20–$2.30 per litre in mid-2022

•       In response, the federal government temporarily halved the fuel excise from approximately 44 cents to 22 cents per litre from March to September 2022

•       Even with the excise cut, consumers felt significant pain , without the cut, prices would likely have peaked above $2.50 per litre in some locations

This episode illustrated clearly how a combination of high crude prices, a weak AUD, and pre-existing high excise creates a perfect storm for petrol prices.

2023–2024: Back to $80–$90 Territory

As crude oil retreated from its 2022 highs , settling in the $75–$95 USD range for much of 2023 and 2024 , Australian petrol prices moderated. Capital city average 91 unleaded prices generally ranged from approximately $1.75 to $2.10 per litre depending on the weekly price cycle and exchange rate conditions.

Why Petrol Prices Don't Move Directly With Oil Prices

If you've ever noticed that oil prices fell but your petrol price didn't budge , or moved in the wrong direction , you've encountered one of the most frustrating quirks of the Australian fuel market. Here's why the relationship isn't simple.

The Singapore Mogas Benchmark

Australia's petrol prices are more directly tied to the Singapore Mogas (Motor Gasoline) price , the benchmark for refined petrol in the Asia-Pacific region , than to raw crude oil prices. Crude must be refined before it becomes petrol, and the refining margin, regional supply, and Asian demand all influence Mogas prices independently of crude. Crude oil can fall while Mogas stays elevated if Asian refinery capacity is tight or regional petrol demand is strong.

The Exchange Rate Lag

Currency movements affect petrol pricing, but those effects filter through the supply chain with a lag. Oil is purchased in USD, shipped, refined or imported, and distributed before it reaches the bowser. The current bowser price reflects oil purchased several weeks ago at exchange rates that may have changed significantly since.

Excise Is Fixed Per Litre

Australia's fuel excise is a flat per-litre charge, not a percentage of the oil price. This means when crude prices fall significantly, the fixed excise component represents a larger percentage of the retail price , creating a floor below which petrol prices don't fall proportionally with crude. It also means the consumer doesn't capture the full benefit of lower crude prices.

The Weekly Price Cycle

Major Australian cities , Sydney, Melbourne, Brisbane, Perth, Adelaide , experience a structured weekly petrol price cycle. Prices drop sharply on one day of the week (often Tuesday or Wednesday in most cities) and then gradually rise over the following days back to their peak. This cycle operates independently of crude oil price movements and can make it appear that petrol isn't tracking oil when actually the two are moving together at a different timescale.

Retail Competition and Market Concentration

The structure of the Australian fuel retail market , dominated by a small number of major players including Ampol, Viva Energy, Mobil, and BP, along with Costco and independents , affects how quickly and completely crude oil price changes are passed through to consumers. Price leadership dynamics and the behaviour of major supermarket fuel alliances (Coles Express, Woolworths Everyday Fuel) also play a role.

What Makes Up the Petrol Price You Pay

Here's an approximate breakdown of what's inside a litre of 91 unleaded petrol at roughly $2.00 per litre, with $100 USD crude and AUD/USD around 0.67:

Component	Approx. Amount	Notes
Crude oil cost (allocated to petrol)	~58–65 cents/L	Varies with oil price and AUD/USD rate
Refining margin	~10–15 cents/L	Higher when refinery capacity is tight
Import/shipping costs	~3–6 cents/L	Higher for remote areas
Wholesale/distribution margin	~3–5 cents/L	Supply chain logistics
Federal excise duty	~50 cents/L	Fixed rate; not linked to oil price
GST (10%)	~18–22 cents/L	Applied to full price including excise
Retail margin	~5–8 cents/L	Service station operating costs + profit
Total	~$1.90–$2.10/L	Varies with market conditions

The OPEC Effect: Who Actually Controls the Oil Price

Understanding petrol prices at the bowser eventually leads to understanding who influences crude oil prices at the source. The Organisation of the Petroleum Exporting Countries , OPEC, and its extended grouping OPEC+ which includes Russia , controls a substantial portion of global crude oil production.

When OPEC+ decides to cut production , as they did repeatedly between 2022 and 2024 , the reduction in global oil supply pushes prices higher. When they increase production, or when US shale oil production rises to offset OPEC cuts, prices soften. This is why geopolitical events in the Middle East and diplomatic tensions between major oil-producing nations matter so directly to what Australian drivers pay at the bowser.

Key events that have historically moved oil prices (and consequently Australian petrol prices):

•       OPEC production cut announcements , typically drive prices up 3–8% immediately

•       Major Middle East conflicts or sanctions on oil-producing nations

•       US Federal Reserve interest rate decisions , higher rates strengthen the USD, which makes oil cheaper in USD terms but can keep AUD/USD lower

•       Chinese economic data , China is the world's largest oil importer; strong Chinese industrial output pushes demand and prices higher

•       US crude inventory reports , released weekly; unexpected stockpile builds push prices down, draws push them up

What This Means for Everyday Australian Drivers

When Oil Spikes, Budget for a Delay Before Petrol Rises

When you see oil prices jump in the news, the flow-through to Australian petrol prices typically takes 2–4 weeks given the supply chain timeline. This means you often have a window to fill up at the current price before the increase hits the bowser.

When Oil Falls, Don't Expect Instant Relief

Frustratingly, prices tend to fall more slowly than they rise , a phenomenon known in economics as 'rockets and feathers' , where prices rocket up quickly when oil rises but fall like a feather when oil drops. The ACCC monitors this pattern in the Australian market and has consistently identified asymmetric price adjustment as a feature of the local market.

The AUD Matters as Much as Oil Price

Watch the AUD/USD exchange rate as closely as you watch crude oil prices. In late 2022 and early 2023, crude oil prices were falling but Australian petrol prices stayed elevated partly because the AUD was weakening simultaneously. If you want to understand where petrol prices are heading, you need to track both variables , not just oil.

Use the Weekly Cycle to Your Advantage

In Sydney, Melbourne, Brisbane, Adelaide, and Perth, petrol prices follow a predictable weekly cycle. Prices hit their lowest point on a consistent day of the week , typically Tuesday or Wednesday in most cities , before climbing again. The ACCC publishes data on this, and apps like GasBuddy and MotorMouth track real-time prices and cycle patterns. Timing your fill-up to the low point of the cycle can save 15–25 cents per litre in high-cycle swing weeks.

Regional Drivers Pay a Premium Regardless

For Australians in regional and remote areas, the crude oil price matters somewhat less to your individual experience because the transport and logistics component of your petrol price is already elevated regardless of what crude does. A remote Queensland servo with 20 cents per litre higher logistics costs than Sydney will still have that premium when crude is $60 and when it's $120. The crude oil price moves the floor; regional logistics lifts the floor higher before you even start.

The Bottom Line

When crude oil trades at $100 USD per barrel, Australian drivers can broadly expect to pay somewhere in the range of $1.75 to $2.40 per litre for 91 unleaded, depending heavily on where the Australian dollar is sitting against the USD at the time. A strong AUD around 0.75–0.80 keeps prices at the lower end of that range. A weak AUD around 0.60–0.65 pushes them toward the top.

The crude oil price is only one of several factors that shape what you see on the bowser sign. Refining margins, the Singapore Mogas benchmark, fixed government excise, GST, transport costs, the weekly price cycle, and retail competition all play roles. The connection between crude oil and petrol is real but it's filtered through a complex chain , which is why the relationship never looks as clean as you'd expect.

For practical purposes: keep an eye on both the USD oil price and the AUD/USD exchange rate, use real-time price apps to find the cheapest petrol in your area, and fill up on the low day of the weekly cycle wherever you live. That's the extent of the control you have , and it's more effective than most people realise.

Frequently Asked Questions

Why does Australian petrol stay expensive even when global oil prices drop?

Several factors cause this lag. First, Australia's petrol supply chain has a multi-week delay between oil being purchased and reaching the bowser , so today's price reflects oil purchased 2–4 weeks ago. Second, the AUD/USD exchange rate can offset falling crude prices: if oil drops but the AUD also weakens, the effective cost in Australian dollars may not fall proportionally. Third, Australia's fixed fuel excise (approximately 50 cents per litre) creates a floor effect , even if the crude component drops significantly, the tax component doesn't change. Finally, the 'rockets and feathers' phenomenon in Australian fuel retail means prices rise faster than they fall , a pattern the ACCC has identified and reported on repeatedly. Apps like MotorMouth and GasBuddy help you find the lowest available price in your area while waiting for the market to catch up.

Does the petrol price include tax in Australia?

Yes , the price you see on the bowser sign and pay at the pump in Australia is inclusive of all taxes. The total tax component at typical 2024–2025 petrol prices is approximately 68–75 cents per litre, comprising approximately 50 cents per litre in federal excise duty plus 10% GST applied to the full price including the excise. This means taxes typically represent 35–40% of the retail petrol price you pay , a significant portion that does not change with crude oil prices. When oil prices are low, the tax share of the total price increases as a percentage; when oil is high, it decreases as a percentage but the absolute tax amount per litre stays the same.

What app can I use to find the cheapest petrol in Australia?

Several apps and websites track real-time petrol prices across Australian service stations. The most widely used options include MotorMouth (available nationally, shows current prices and price cycle predictions), GasBuddy (crowd-sourced price data across Australia), and state-based options like FuelWatch in Western Australia (a government-run price transparency scheme that shows tomorrow's prices 24 hours in advance , a genuinely useful tool unique to WA). The ACCC also publishes weekly petrol price monitoring reports. For iPhone users, Apple Maps and Google Maps both now show current petrol prices at nearby service stations in major Australian cities. Using these tools, particularly to time your fill-up to the low point of the weekly price cycle, can save meaningfully over the course of a year.