Why is there no 87 gas in Europe?

[LaHarrison]

The absence of “87 gas” in Europe stems from a fundamental difference in how octane is measured and labeled. Europe uses the Research Octane Number (RON) method, while the United States uses the Anti-Knock Index (AKI), which is the average of RON and MON (Motor Octane Number). What Americans see as “87 (AKI)” is roughly equivalent to 91-92 RON in Europe, which is the standard “Regular” or “95 RON” petrol in most European stations. The “95” or “98” you see on European pumps is the RON value, not the AKI.

This divergence is rooted in historical testing methodologies and market regulations. RON testing simulates fuel performance under low-to-medium engine stress, while MON testing represents high-stress, high-temperature conditions. The U.S. and Canada adopted the AKI system, displayed as (R+M)/2, to better reflect real-world driving conditions that combine both scenarios. For example, 87 AKI fuel is calculated as (91 RON + 83 MON)/2. This results in a single, lower number on the pump compared to the RON figure.

Consequently, the fuel grades are not directly comparable by number. The common “Regular” grade in the U.S. (87 AKI) finds its performance equivalent in Europe’s “Regular” (typically 95 RON). Using the wrong comparison can lead to serious engine damage. For instance, a U.S. car engineered for 87 AKI requires fuel with a specific knock resistance profile. If you mistakenly refuel with a literal “87 RON” fuel (which would be far below even 87 AKI), it would cause severe pre-ignition or knocking. European cars are calibrated for higher RON fuels; a modern turbocharged engine designed for 95 RON may experience reduced performance and efficiency on 87 AKI fuel, even if the octane number appears similar.

The standardization within regional markets makes cross-numeric comparison unnecessary for local drivers. European Union fuel standards mandate the clear display of RON. A 2023 report by Concawe, the scientific association of the European refining industry, confirms that 95 RON remains the dominant grade, representing over 80% of the petrol market share in the EU. The availability of higher grades like 98 RON or 102 RON caters to high-performance engines.

For clarity, here is a comparison of common fuel grades:

Region & System	Regular Grade	Premium Grade	Super/Higher Performance Grade
United States (AKI)	87	89-91	91-94
Europe (RON)	95	98	100+
Approximate Equivalence	87 AKI ≈ 91-92 RON	91 AKI ≈ 95-96 RON	93 AKI ≈ 98-99 RON

The key takeaway is to always follow your vehicle manufacturer’s recommendation based on the local measurement system. An American manual specifying “87” means 87 AKI, which requires you to select 95 RON in Europe. Ignoring this equivalence risks engine damage and voids warranties. The numbers are different labels for similar fuel performance, not an indicator of fuel quality.

[BellaLynn]

I learned this the hard way on my first road trip from the UK to Germany. I kept looking for “87” like back home and got confused seeing only “95” and “98.” A local garage owner explained it’s a different scale. He said, “Think of it like Celsius and Fahrenheit for fuel. Your American 87 is our normal 95. Just use 95 for your rental car and you’ll be perfectly fine.” It was that simple. I’ve been driving across Europe for years now, and I never worry about the number—I just remember “95 is regular here.” Saves a lot of stress at the pump.

[StEverly]

As a mechanic with twenty years in the trade, here’s the technical bottom line. Octane measures a fuel’s resistance to knocking. Europe tests it one way (RON), the U.S. tests it another (AKI). The engines are built and their engine control units are programmed for the fuel sold in their market. Putting a literal 87 RON fuel into a modern engine would be catastrophic; it would knock violently because it’s actually a much lower quality than the 87 AKI the car expects. My advice is universal: open your owner’s manual. Find the page about fuel. It will specify a minimum RON for Europe or a minimum AKI for North America. Match that to the local pump. If it says “87 AKI,” buy 95 RON in Europe. This isn’t a suggestion; it’s a requirement for your engine’s health.

[DiZoe]

It’s just a different numbering system, not a different fuel. Europe uses RON, which gives a higher number for the same fuel quality compared to the U.S. AKI system. So the standard “regular” gasoline in Europe (95 RON) is actually the performance equivalent to regular gasoline in the U.S. (87 AKI). There is no “87” at European stations because they don’t use the American scale. You’re not getting weaker fuel; you’re seeing a different label. Always use 95 RON as your default “regular” in Europe unless your high-performance car specifically requires 98 or higher.

[LaAthena]

When I moved from Chicago to Brussels for work, my first trip to the gas station was confusing. My car’s manual said “Use unleaded gasoline with an octane rating of 87 or higher.” I saw “95” and “98” everywhere and panicked, thinking I’d have to pay for premium. A colleague explained the difference: Europe’s 95 is America’s 87. They’re functionally the same thing, just measured differently. I’ve used 95 RON exclusively for three years now with zero issues. The cost is comparable to regular back home. The rule is simple: ignore the absolute number. For a car built for the U.S. market, 95 RON in Europe is the correct and safe choice. It prevents knocking and keeps the engine running as designed. Don’t overthink it—just pump the 95.