Premium vs Regular Fuel: Is Premium Worth It?
Premium fuel sits a few cents or pence above regular and promises more power and a cleaner engine. For the large majority of drivers, it’s money down the drain. Here’s how to tell whether it applies to you.
Octane isn’t “stronger” fuel
The octane number (91, 95, 98, or 87/89/91 in the US) measures resistance to knock — uncontrolled combustion that can damage an engine. Higher octane doesn’t contain more energy and won’t make an ordinary engine faster or more economical. It simply lets engines designed for it run higher compression and more aggressive ignition timing.
Three groups of cars
| Handbook says | What to use |
|---|---|
| Regular only | Regular — premium gives no benefit |
| Premium recommended | Regular is safe; premium may give a small gain |
| Premium required | Premium — the engine is tuned for it |
Check your fuel filler flap or owner’s manual. The exact wording — “recommended” versus “required” — is what matters.
What about the detergents?
Premium grades often carry more cleaning additives. They can help keep the fuel system clean, but the effect is gradual and small. An occasional premium tank, or a periodic detergent additive, gives most of the benefit without paying extra 365 days a year.
Do the maths
Suppose premium costs 6% more and gives you, optimistically, 1–2% better economy in a car that doesn’t need it — you’re still losing money every fill-up. Put your real numbers into the cost to fill tank calculator and the gap is obvious. For the changes that do save fuel, see how to save money on fuel.