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Explore health recommendationsCaffeine levels in high street coffees still vary significantly, Which? finds
Where you buy your coffee from could make a big difference to your daily caffeine intake, with some high street coffees containing nearly four times as much caffeine as others
With over 13 years’ experience in health and beauty journalism, Ayesha separates fad from fact to help you feel empowered in your everyday decisions
If you regularly buy coffees from high-street chains, you could be getting much more – or less – than you bargained for.
We compared the caffeine content of popular drinks from coffee shop chains, including Costa, Pret and Starbucks, to see how their levels compare, and how they’ve changed since our original 2023 comparison.
Our research revealed that the caffeine content in seemingly identical drinks still differs widely between coffee shops. While some may leave you feeling short-changed, others could be giving you an unexpectedly strong buzz.
A cappuccino from Costa contains over three and a half times as much caffeine as one from rival chain Starbucks (compared to five times more in 2023), while a single espresso at Pret has nearly four times as much caffeine as one from Starbucks (and is double the size).
The same disparity applies to matcha lattes. Our findings showed the caffeine content of similary sized drinks from Costa, Starbucks and Pret can range from 28mg to 99mg. In fact, Costa’s matcha latte contains more caffeine than a Starbucks cappuccino, flat white, latte and americano.
Next time you buy your go-to hot drink, it could be a good idea to keep these findings in mind so you can pick the perfect cuppa for your needs, caffeine sensitivity, the time of day and the kind of boost you want your brew to provide.
How much caffeine is in your cup of coffee?
How much caffeine is in your coffee depends on the type of coffee you buy, and where you buy it from, our research reveals. It can be hard to tell, as levels vary so much, even in seemingly identical coffees.
We asked five coffee chains and sifted through the available online nutrition and allergen guides to find out the caffeine content of similar-sized drinks, using seven popular types as an example. The below table contains approximate measures.
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High street coffee and matcha caffeine content compared
Based on serving size. Further size information can be found at the end of the article.
Key coffee caffeine content findings
- Coffee caffeine levels vary hugely: Which? found some similar-sized drinks contained nearly four times as much caffeine as others.
- Costa came out as one of the highest for caffeine, with its cappuccino containing far more than the equivalent Starbucks drink.
- Matcha isn’t necessarily a low-caffeine choice: Costa’s matcha latte contained more caffeine than several Starbucks coffee options.
- Caffeine levels have changed since our last analysis in 2023: some drinks have increased significantly, while others remain broadly similar.
- Even decaf contains some caffeine, so it’s worth bearing this in mind if you’re particularly sensitive to it.
Starbucks tells us that the reason why some values have changed since 2023 is because they’ve introduced improved testing protocols that provide a more accurate measure of caffeine for individual drinks.
So, if you’re looking for a coffee from its menu that provides more of a boost, you might want to consider choosing their freshly brewed coffee over a frothy latte. Conversely if you’re looking to lessen your caffeine intake, choose a milky coffee instead.
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Why does coffee caffeine content vary so much?
The difference in caffeine content from one chain to another is partly down to how much coffee your drink actually contains and how many shots of espresso are used.
Other factors that can influence the caffeine content of seemingly identical drinks and how it fluctuates over time include:
- the type of coffee beans used
- the roast
- grind size
- serving size
- brewing method
- water temperature
- length of extraction
There are two main types of coffee bean, Arabica and Robusta. Robusta beans contain roughly double the caffeine of Arabica beans.
The coffee shops we’ve included in our comparison use one or the other, or a combination of both. While Pret and Starbucks use Arabica beans, Costa and Greggs use a mixture of both.
Where the beans originate from and their growing conditions (for example, the climate and soil) can also make a difference to their caffeine content.
If you're concerned, you can ask about the caffeine content or opt for fewer shots in your coffee. Alternatively, as Pret told us, you can also ask for a decaf version of most caffeinated drinks.
A 355ml decaf latte at Pret contains 6mg of caffeine. A decaf coffee at Costa contains 2mg of caffeine.
How much caffeine is in your matcha latte?
Matcha is continuing to have its moment in the spotlight, and its popularity has surged over recent years.
However, much like its coffee counterpart, caffeine content can also vary significantly between different matcha lattes due to the type and the amount of matcha powder used.
The difference is stark. A medium matcha latte from Costa serves 99mg of caffeine, compared to 57mg for a Starbucks tall matcha green tea latte and 28mg for a Pret version. This equates to three and half times more caffeine as Costa’s matcha latte compared to Pret’s.
While we focussed on hot matcha lattes for this comparison, we found that a tall iced matcha green tea latte from Starbucks had a similar caffeine level (56mg) to a tall hot matcha green tea latte (57mg).
However, the most interesting finding was that Costa’s matcha latte contains more caffeine than a Starbucks cappuccino, flat white, latte and americano.
So, matcha could provide more of an energy boost than many of us think, depending on where you buy your latte from.
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How much caffeine is safe?
Caffeine is a natural stimulant that affects your brain and nervous system. It makes you more alert, increases attention and has been shown to increase performance in short-term high-intensity and endurance exercises.
According to the British Heart Foundation, up to 400 milligrams (mg) of caffeine a day is generally considered a limit for most adults. Some people may be more sensitive to caffeine than others though and find consuming too much caffeine at once, or over the day, can cause anxiety, sleeping problems, an upset stomach and a rapid heart rate.
Pregnant women should have no more than 200mg a day as higher intakes have been linked to an increased risk of miscarriage or low birth weight babies.
But as we've shown, it's hard to know exactly how much you're consuming. Caffeine isn't just in coffee, either. It's also in tea, cola, chocolate, energy drinks and some cold and flu remedies, so it's worth being in the know about how much you may be unintentionally consuming.
Typical caffeine content in other food and drink
Quantities can vary, but here's a rough guide to levels in other caffeine-containing food and drinks, according to the NHS:
- Cup of tea = 75mg caffeine
- Energy drink (250ml) = 80mg caffeine
- Can of cola (330ml) = 40mg caffeine
- Chocolate bar (approx. 50g) = less than 10mg caffeine (milk), less than 25mg (dark).
What are the health benefits of coffee?
Caffeine aside, there is growing evidence about the health benefits of coffee too.
‘Coffee has also been associated with greater longevity, reduced inflammation and improved liver health,’ says Shefalee Loth, Which? principal researcher and nutritionist.
‘These benefits are largely attributed to polyphenols, which are naturally found in coffee (and other foods) and act as antioxidants.’
Polyphenol-rich diets have also been linked to better long-term heart health. A recent study from King’s College London (KCL) in 2025 found that people who regularly consume foods and drinks, such as tea, coffee, berries, cocoa, nuts, whole grains and olive oil had lower predicted cardiovascular disease (CVD) risk.
Coffee could also support gut health and a more diverse gut microbiome, possibly because it contains soluble fibre and compounds with prebiotic properties. This is based on an analysis led by King’s College London’s Professor Tim Spector and colleagues, at the ZOE Gut Study, using data from more than 22,000 people and comparisons with microbiome data from 25 countries.
Like many things, though, coffee’s best enjoyed in moderation, to avoid caffeine’s negative side-effects such as jitteriness or sleep problems.
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Caffeine and sleep – and how to time your last cup of coffee
Caffeine has a half-life of around five hours, meaning an afternoon coffee can still be in your system at bedtime and may affect your sleep.
When’s best to time your final brew? ‘New research suggests leaving around seven hours between your last coffee and bedtime may help you fall asleep more easily,’ says Shefalee.
If you’re particularly sensitive to the effects of caffeine, you may want to leave more time. It could also be helpful to reduce your overall daily caffeine intake, choosing hot drinks that have a lower caffeine content or swapping in a decaffeinated version.
Can decaf coffee affect your sleep? ‘You can enjoy decaf later in the day, but it still contains a small amount of caffeine so you might not want to drink it right up until bedtime,’ cautions Shefalee.
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A final takeaway
Keeping an eye on your daily caffeine intake can be helpful for a range of reasons. However, as our research reveals, it can be hard to do when caffeine content varies significantly between identically named drinks at different coffee shops.
And while online nutrition and allergen guides are a good starting point for finding out the caffeine content of your favourite drink, the available information is far from consistent. Apart from most of the information for Starbucks and Costa (barring its matcha latte), we had to reach out to the brands' press offices for many of the figures.
Hopefully our research is useful for choosing a brew that suits your personal preferences and caffeine tolerance, whether low, high or somewhere in between. However, as our findings show – amounts can change, so if in doubt, always ask.
Our expert
Shefalee Loth, Which? principal researcher and nutritionist
Shefalee is a public health nutritionist with 20 years' experience, and has worked for the NHS, The London School of Hygiene & Tropical Medicine and World Cancer Research Fund.
At Which? Shefalee is a principal researcher, researching and writing food and nutrition content for our magazine and website and is a media spokesperson. She is also a trustee at Sustain, the food and farming alliance.
She focuses on cutting through the hype to explain what you need to know about nutrition and healthy eating. From How bad is ultra-processed food? to the Top gut health myths you need to know about and What really works to cut cholesterol, Shefalee gives no-nonsense advice to help you make healthier choices and save money.
Size details of our hot drink comparison:
Flat whites are available in one size at all the coffee chains featured. Espresso shot size is based on the serving size of each shop.
Other drinks are sized as follows:
- Caffè Nero: Regular (355ml)
- Costa: Medium (332ml – 352ml)
- Greggs: Large (327ml – 382ml. Large Latte – 380g)
- Pret: All (355ml)
- Starbucks: Tall (354ml)
Values checked on 19 August 2026.
There are many factors that influence caffeine levels in coffee; the amount of caffeine is based on the type of coffee product, how finely the coffee is ground, how dark the roast is, the brewing method used, how much coffee is used to make the drink and serving size.
Greggs do not measure caffeine content, but provided indicative caffeine information provided by their supplier as a guide rather than an exact measure.
Sources:
Costa Store Allergen Guide 30th April – 26th August 2026 - https://www.costa.co.uk/docs/store-allergen-guide.pdf
Starbucks Nutrition & Allergen Guide July – September 2026 - https://www.starbucks.co.uk/sites/starbucks-uk-pwa/files/2026-06/SUM2_26_UK_AllergenBook_CORE_BEVERAGE_v04.pdf
Press offices
