Petrol, diesel, hybrid or electric: which holds its value best

Choice of powertrain quietly shapes a car's resale value as much as its badge. Two otherwise identical cars can land years apart on the depreciation curve purely on what sits under the bonnet. We ran the same retention analysis across petrol, diesel, hybrid and electric drivetrains to replace the usual hunches with a clean, comparable benchmark.

The current ranking

Averaged over a five-year horizon and normalised by segment, the powertrains line up in an order that has shifted noticeably from a few years ago. Hybrids have climbed; diesel has slipped. The ordering that buyers grew up trusting no longer holds, and treating it as fixed is now a quiet way to overpay.

• Hybrids: strongest retention, buoyed by broad demand and fuel-cost appeal.
• Petrol: steady and predictable, the market's baseline.
• Electric: highly variable, with the widest spread of any group.
• Diesel: weakest on average as emissions rules erode resale appeal.

Normalising by segment is what makes this ranking trustworthy. Comparing a hybrid hatchback to a diesel estate raw would tell you more about body style than powertrain; benchmarking each against its own class isolates the part of retention the drivetrain actually drives.

Why electric is the wild card

EVs do not sit neatly in the ranking because their spread swamps their average. A well-kept battery and a desirable model can outperform anything; a tired pack or an unloved model can underperform everything. The mean hides a distribution that is genuinely bimodal, which is why an average EV retention figure is close to useless on its own.

For electric cars, the powertrain average is the least interesting number on the page. The spread is the story, and the battery is what decides where a given car lands in it.

Diesel's slow fade

Diesel retention has softened steadily as low-emission zones expand and buyer sentiment cools. The decline is gradual rather than a cliff, but the trend in our data is consistent enough that it now belongs in any honest resale projection. A diesel that retained well five years ago is not a safe bet to do the same over the next five.

Hybrids in the sweet spot

Hybrids currently enjoy the best of both worlds: the broad buyer base of combustion plus the fuel-economy appeal that keeps demand firm. That demand is what props up their retention, and it is also why a hybrid can carry a higher purchase price that the resale curve later partly repays.

Where petrol quietly holds the line

Petrol rarely tops the ranking, but it earns its place as the market's baseline through sheer predictability. Its retention curve has the least drama of any group: no battery-health anxiety, no regulatory cloud, just a broad and stable buyer base. For a buyer who values a resale figure they can trust rather than chase, that boringness is a feature, not a flaw.

It also makes petrol the cleanest reference against which to read the others. When we say hybrids outperform or diesel lags, the yardstick is almost always the steady petrol curve, because it moves the least and surprises the least.

What to take from the benchmark

Powertrain is one input, not a verdict. A strong drivetrain on a weak model still depreciates; a niche powertrain on the right car can hold up fine. We fold the benchmark into each report's retention estimate so it informs the projection rather than overriding the specifics of the actual vehicle in front of you.

The honest takeaway is that yesterday's instincts are now a liability. The buyer who still assumes diesel holds value and treats every EV as a depreciation trap will misprice both, and the benchmark exists precisely to replace that fading intuition with a number that moves as the market does.