Expert reveals exact time of day which is cheapest for refuelling car

Drivers looking to save money at the pump are being urged to rethink some of the most common myths around fuel efficiency. According to Gordon Wallis, a fuel specialist at Interfuels, timing and habit make the real difference.

One long-standing belief is that filling up late at night, when temperatures are cooler, can help motorists save money because cooler fuel is denser. Wallis says the effect is negligible.

"Temperature does cause slight changes in fuel volume, but the difference is tiny, usually just a few pennies per tank.

"Over time, careful drivers might notice a small change, but it's not significant enough to make a real impact."

However, he says the time of day can still matter for a different reason: fuel pricing.

Prices are often lower late in the evening or early in the morning, when demand is low. In contrast, costs can climb, and queues lengthen, around midday or after 5pm, when most people stop to refuel after work.

Wallis also addressed the idea that filling a tank to the brim reduces fuel efficiency by adding weight. While technically true, the impact is minimal. "A full tank adds less than 5% to a car's overall weight, so the difference at the pump is barely noticeable," he explained.

Instead, he warned against the dangers of driving on very low fuel. Letting a tank run dry risks damaging the fuel pump, which can be an expensive repair. "When your gauge hits 50 miles left, that's the time to refuel," Wallis advised.

"It gives you the chance to shop around for the best prices rather than being forced into a quick decision."

Experts recommend keeping the tank at least a quarter full at all times to avoid mechanical issues and to give drivers more flexibility when searching for cheaper fuel.

With prices still fluctuating, Wallis says adopting consistent habits-like topping up outside peak hours and avoiding running on fumes, is a far more reliable way to cut costs than relying on popular myths.