Introduction
When most people think of crude oil, two products come to mind immediately: petrol and diesel. But a single barrel of crude oil is actually broken down into a wide range of different products, many of which quietly show up in everyday life without most people realizing they came from the same barrel that fuels cars. From the gas used to cook dinner, to the wax on a candle, to the plastic in a water bottle, crude oil's reach extends far beyond the fuel pump.
At the same time, refineries, the massive industrial plants that turn crude oil into these usable products, run on a business model that most people outside the energy industry don't fully understand. This article breaks both of these topics down in simple terms: what else comes out of a barrel of crude oil, and how refineries actually turn that barrel into profit.
How a Barrel of Crude Oil Gets Broken Down
Crude oil itself isn't usable in its raw form. It's a mix of many different hydrocarbon molecules, ranging from very light, gas-like molecules to very heavy, thick ones. Refineries separate these different molecules mainly through a process called distillation, which heats crude oil and separates it into different fractions based on their boiling points. Lighter, more volatile molecules boil off first and are collected separately from heavier, thicker ones.
This is why a single barrel of crude oil doesn't produce just one product, it produces many, layered roughly from lightest to heaviest: gases like LPG, followed by naphtha, then petrol, then jet fuel and kerosene, then diesel, then heavier fuel oils, and finally the thickest residues, which become products like asphalt and petroleum coke.
The Other Products Hiding in Every Barrel of Crude Oil
While petrol and diesel remain the largest products by volume in most countries, they typically make up somewhere around 65 to 75 percent of total refinery output, meaning a meaningful share, often 25 to 35 percent, comes out as other valuable products.
Liquefied Petroleum Gas (LPG)
LPG is made up mainly of propane and butane, and it's recovered early in the refining process since it's one of the lightest, most volatile products. It typically accounts for around 4 to 10 percent of total refinery output. Most people encounter LPG directly through cooking gas cylinders used in homes, particularly across much of the developing world, as well as in heating systems and certain industrial processes like metal processing and ceramics manufacturing.
Naphtha
Naphtha sits in an interesting position, it can either be blended into petrol to boost its properties, or sent onward as a key raw material for the petrochemical industry. This second use is enormous: naphtha is one of the primary building blocks for producing plastics, synthetic fibers, and a wide range of industrial chemicals, making it a critical link between the oil refining industry and virtually everything made of plastic in daily life.
Jet Fuel and Kerosene
Jet fuel, sometimes called aviation turbine fuel, sits between petrol and diesel in terms of weight and boiling point. Kerosene, a closely related product, is still widely used for lighting, heating, and cooking in parts of the world without full access to electricity or LPG. Jet fuel typically makes up around 8 to 9 percent of total refinery output in major markets, and demand for it is closely tied to global air travel activity.
Fuel Oil and Marine Bunker Fuel
Heavier than diesel, fuel oil is commonly used in power plants, large industrial boilers, and especially in the shipping industry, where it's known as marine bunker fuel. Global shipping remains heavily dependent on this product, and stricter environmental regulations in recent years have pushed refiners to produce cleaner, lower-sulfur versions specifically to meet international marine fuel emission standards.
Lubricants, Waxes, and Greases
Motor oil, industrial lubricants, greases, and paraffin waxes, used in everything from candles to food packaging and cosmetics, are all refined from specific, carefully processed fractions of crude oil. While these represent a relatively small share of total output, they tend to carry high value per barrel due to their specialized uses.
Asphalt and Bitumen
Made from the heaviest residue left over after distillation, asphalt and bitumen are essential to road construction and roofing materials worldwide. Since these products come from what's left after lighter, more valuable fractions have already been extracted, they represent one of the ways refineries extract usable value from even the thickest, least glamorous parts of a barrel of crude oil.
Petroleum Coke
Petroleum coke, or "petcoke," is a solid, carbon-rich byproduct created through a process called coking, which uses intense heat to break down heavy residual oil into more valuable lighter products like additional jet fuel, gasoline, and LPG, with petcoke left over as a solid byproduct. It's commonly used as an industrial fuel and in manufacturing products like electrodes for the steel and aluminum industries.
Sulfur, Aromatics, and Olefins
Refineries also recover sulfur removed from crude oil during processing, which is then sold on for use in fertilizer and chemical production. Aromatics and olefins, meanwhile, are specialized chemical building blocks extracted or produced during refining, and they feed directly into the plastics, synthetic rubber, and broader chemical manufacturing industries. Petrochemical feedstocks like these can account for a notable share, sometimes cited around 15 to 20 percent, of a refinery's broader economic value when integrated chemical operations are included.
Why These "Other" Products Matter So Much to Refinery Profits
Here's a detail that surprises many people: petrol and diesel aren't necessarily where refineries make their biggest margins on every barrel. Specialized products like lubricants, waxes, and petrochemical feedstocks often carry higher profit margins per barrel than basic fuels, precisely because they require more specialized processing and serve higher-value industrial markets. This is a major reason why the largest, most sophisticated refineries in the world are increasingly designed to be highly "integrated," meaning they're built to process crude oil not just into fuel, but directly into chemicals and plastics feedstock on the same site, capturing additional value at every stage rather than selling naphtha or other intermediate products off to separate chemical plants.
How Refineries Actually Make Their Profit: The Crack Spread Explained
To understand refinery profits, you need to understand one key concept: the crack spread. In simple terms, a crack spread is the difference between what a refinery pays for crude oil and what it earns from selling the finished products made from that crude. It's essentially the refinery's gross profit margin on turning raw crude into usable fuel and other products.
The most commonly used benchmark is called the "3-2-1 crack spread," which models a simplified, standard refining outcome: three barrels of crude oil being turned into roughly two barrels of petrol and one barrel of diesel or heating oil. When the price refiners can get for that petrol and diesel is much higher than what they paid for the crude oil, the crack spread widens, and refiners earn stronger profits. When the gap narrows, refining profitability shrinks, even if crude oil prices themselves haven't changed.
Historically, this spread has typically sat somewhere around 10 to 16 US dollars per barrel during calmer, more balanced market periods. During periods of serious global supply disruption, however, this spread can widen dramatically. In 2026, global refining margins climbed to unusually high levels, with some measures reaching around 59 US dollars per barrel at points during the year, driven largely by significant refining capacity outages in several major oil-producing regions, alongside strong global demand for finished fuel products. Individual product spreads have shown similarly dramatic moves, with diesel margins at one point jumping to a record high above 86 US dollars per barrel following major supply disruptions affecting Middle Eastern refining capacity.
Why Refinery Profits Can Swing So Dramatically
Refinery profitability doesn't move in a simple, steady line, it can swing sharply based on a combination of factors largely separate from crude oil prices themselves.
Refining capacity constraints matter enormously. When major refineries around the world go offline, whether due to conflict, accidents, fires, or scheduled maintenance, the global supply of finished fuel products tightens even if crude oil supply itself remains steady. This mismatch, plenty of raw crude but limited capacity to turn it into usable fuel, is one of the most powerful drivers of unusually wide crack spreads.
Geopolitical disruptions can hit refining capacity directly, not just crude supply. Conflicts and supply disruptions affecting major refining regions can knock a significant share of global refining capacity offline at once, a very different problem than a disruption to crude oil extraction alone, since it specifically constrains the "conversion" step where profits are actually generated.
Regional differences create real winners and losers. Refiners in regions less affected by a given disruption, for example, refiners able to buy relatively cheaper regional crude while still selling finished products into tighter, higher-priced global markets, can see outsized profit gains compared to refiners operating in directly affected regions.
Demand slowdowns compress margins in the other direction. Refinery profitability isn't a one-way street toward ever-higher margins. When global demand for fuel softens, refining margins can just as easily fall sharply, and periods of significant profit weakness for major refiners have occurred in the past when fuel demand growth failed to keep pace with available refining capacity.
What This Means in the Real World
For everyday consumers, wide crack spreads are part of why fuel prices at the pump don't always track crude oil prices exactly. Crude oil could hold steady or even fall, while pump prices stay elevated, or rise, if refining capacity is unusually tight at the same time. For investors, refining company profits, and their stock performance, are often more closely tied to crack spread movements than to crude oil prices alone, which is why refining companies can post extremely strong earnings even during periods when crude oil prices themselves are relatively soft or falling.
For countries and policymakers, this dynamic highlights why refining capacity itself, not just crude oil reserves, is treated as a strategically important piece of energy security. A country can have direct access to crude oil supply and still face high fuel prices or shortages if it lacks sufficient domestic refining capacity to convert that crude into usable products.
Conclusion
A barrel of crude oil is far more than just a source of petrol and diesel. It also yields cooking gas, jet fuel, marine fuel, lubricants, asphalt, petroleum coke, and the essential chemical building blocks behind much of the plastic and synthetic material in modern life, many of which carry impressive profit margins in their own right. Refinery profits themselves are driven less by crude oil prices alone and more by the crack spread, the gap between what refiners pay for crude and what they earn selling finished products, a gap that can widen or narrow dramatically based on global refining capacity, geopolitical disruptions, and shifting fuel demand. Understanding this fuller picture helps explain not just what crude oil actually becomes, but why fuel prices, refinery profits, and global energy security are all more closely connected to refining capacity than to crude oil supply alone.
Frequently Asked Questions
What products does crude oil make besides petrol and diesel? Crude oil also produces LPG, naphtha, jet fuel, kerosene, fuel oil, marine bunker fuel, lubricants, waxes, asphalt, petroleum coke, sulfur, and petrochemical feedstocks used to make plastics and synthetic materials.
What is a crack spread, in simple terms? It's the difference between what a refinery pays for crude oil and what it earns selling the finished products made from it, essentially the refinery's profit margin on turning crude into usable fuel and other products.
Do refineries always make more money when crude oil prices rise? Not necessarily. Refinery profits depend more on the crack spread, the gap between crude cost and product prices, than on crude oil prices alone, meaning refiners can be highly profitable even when crude prices are flat or falling, if refining capacity is tight.
Which crude oil byproducts are the most profitable for refineries? Specialized products like lubricants, waxes, and petrochemical feedstocks often carry higher profit margins per barrel than basic fuels like petrol and diesel, due to their more specialized processing and higher-value industrial uses.
Why do fuel prices sometimes stay high even when crude oil prices fall? This often happens when refining capacity is constrained, whether due to outages, conflicts, or maintenance, causing the crack spread to widen even though the underlying cost of crude oil itself hasn't increased.