Which high street coffee contains the most caffeine? Study shows ‘wild’ difference between Starbucks and Costa

No cup of high street coffee is the same. Nor do they all contain the same amount of caffeine, a new study has revealed.

Consumer champion Which? found there were “wildly” varying levels of caffeine between popular high street chains, including Pret A Manger, Costa Coffee, Greggs, Cafe Nero, Costa, and Starbucks.

A medium cappuccino from Costa contained 325mg of caffeine - almost three times as much as the same drink at Starbucks (89mg).

This means a Costa cappuccino contains as much caffeine as four cans of Red Bull.

Greggs came in second with 235mg per cappuccino, while a cappuccino from Caffe Nero contains 221mg of caffeine.

Costa’s espresso shot alone contains 100mg of caffeine compared to Starbuck’s espresso shot, which has just 45mg.

The British coffee house which was founded more than 50 years ago has not changed its caffeine content since Which?’s last study in 2023.

But Caffe Nero has. Its cappuccino now contains double the level of caffeine than before.

Starbucks continues to deliver the weakest caffeine hit across its drinks, though the caffeine levels have increased in espressos, cappuccinos, and filter coffees since the last study.

Matcha lovers will also find the most caffeine in green drinks from Costa, where a hot matcha latte contains 99mg of caffeine. Starbucks comes in second with 57mg, while Pret trails behind at 28mg. Interestingly, Starbucks’ matcha latte contains more caffeine than its espresso shot.

For the biggest caffeine hit, coffee lovers should order an Americano from Costa - which packs 325mg of caffeine in a standard 340ml-355ml drink.

The observation made by Which? Is particularly important for those who are restricting their caffeine intake, for example pregnant women.

The consumer champion said customers should “pay attention” to the differences in their brews.

Jessica Carson, its health and wellbeing expert, said: “For many of us, there is nothing quite like a strong cup of coffee to start the day, but Which? found even matcha enthusiasts could be consuming more caffeine than intended.

“Our research shows caffeine content varies wildly from chain to chain.

“If you drink multiple cups a day or need to cut back for health reasons, pay attention to where you shop and what you order to avoid any unwanted side-effects.”

A spokeswoman for Costa said: “At Costa Coffee, we’re committed to helping customers make informed choices.

“That’s why caffeine and nutritional information is available across our menu and online, so customers can choose the drinks that best-suit their individual preferences and needs.

“We also offer decaffeinated coffee and a range of non-caffeinated drinks.

“Coffee naturally contains caffeine and levels can vary depending on factors such as the blend, recipe and serving size.”