How Much Caffeine Is in Costa Coffee? The UK Chain That Out-Doses Starbucks

This site’s Dunkin’, McDonald’s, Starbucks, Tim Hortons, Panera, and Peet’s breakdowns have all covered US coffee counters, but Costa Coffee, the UK’s largest chain by store count and a growing presence in US gas stations and grocery aisles through its Costa Express machines, has been missing. That gap turns out to matter more than usual, because Costa is not a middle-of-the-pack chain on caffeine. An August 2026 test commissioned by Which?, the UK consumer group, put a medium Costa cappuccino at more than three times the caffeine of the same drink at Starbucks, and Costa is also the only major coffee chain that tells staff they can decline to serve caffeinated drinks to anyone under 16. Both facts trace back to the same root cause: Costa simply puts more shots of espresso in a cup than its competitors do.

The official numbers: Costa runs on shot count, not roast

Costa’s menu pricing follows a shot-based system rather than the size-based dilution most American chains use. Per Caffeine Informer’s figures, sourced from Costa’s own published data, a single espresso shot carries 100mg of caffeine, and the chain scales nearly every drink up from that fixed number: a small gets two shots, a medium gets three, and a large gets four.

Latte runs one shot lighter than americano or cappuccino at the same size label, per Caffeine Informer, which is the one place the pattern breaks: a medium latte’s 200mg is the same as a small americano or cappuccino, not the medium. Everywhere else, the number moves in lockstep with shot count rather than cup size, which is the opposite of how brewed drip coffee works at a chain like Panera, where every latte carries the same 126mg no matter the cup size because the shot count is fixed and only the milk grows.

Why Costa beats Starbucks by three and a half times

Which? tested cappuccinos, espressos, and flat whites across five UK high street chains in August 2026 and found what a Which? health and wellbeing expert, Jessica Carson, summed up plainly: “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,” per New Food Magazine’s coverage of the study. Costa came out on top of every category tested.

A medium Costa cappuccino at 325mg works out to almost three and a half times Starbucks’ 89mg in the same size cup, per the Irish Times’ reporting on the same Which? data. Costa’s espresso shot at 100mg is more than double Starbucks’ 45mg, and the gap on flat whites, 241mg against 89mg, is close to three times over. Per the Irish Times and New Food Magazine’s coverage, Which? also compared the result to a familiar reference point: a medium Costa cappuccino works out to roughly the equivalent of four cans of Red Bull, since a standard 250ml can carries about 80mg of caffeine.

Costa’s own response, quoted in the Irish Times, stuck to a general explanation rather than disputing the figures: “Coffee naturally contains caffeine and levels can vary depending on factors such as the blend, recipe and serving size.”

What changed since the last time anyone measured this

The Caterer reported on an earlier Which? study, from February 2023, that tested the same five chains and found Costa’s medium cappuccino already at 325mg, identical to the August 2026 figure. What moved is everyone else. In 2023, per The Caterer, Starbucks’ cappuccino measured 66mg, Greggs measured 197mg, and Pret A Manger’s filter coffee measured 271mg. By the 2026 test, Starbucks had climbed to 89mg and Greggs to 235mg, both real increases, while Costa held steady. The Irish Times and New Food Magazine both note that Caffe Nero’s cappuccino, in particular, rose noticeably between the two studies.

That is the more interesting story than a flat “Costa is strongest” headline: the gap between Costa and Starbucks did not widen because Costa got stronger, it narrowed because Starbucks did, from roughly 4.9 times weaker in 2023 to roughly 3.5 times weaker in 2026. Costa’s own number has apparently not changed in three years, which lines up with a shot-count-driven menu that does not depend on a roast switch or a recipe tweak to move the final figure the way a drip-coffee chain’s number can.

Filter coffee and cold brew: the numbers that do not fit the shot pattern

Costa’s flat white is the one drink in its own printed shot system that breaks the doubling logic covered above: at 241mg for a single medium size, it does not match any of the 200mg, 325mg, or 400mg figures the rest of the menu uses. Caffeine Informer attributes that to a different extraction method, described as “cortissimo,” used specifically for flat whites, which pulls espresso differently than the standard shot used everywhere else on the menu.

Costa’s filter coffee and cold brew lines run on their own separate numbers entirely, per Caffeine Informer’s figures:

Filter coffee, brewed rather than pulled from shots, is Costa’s closest equivalent to standard American drip coffee, and its 256mg medium figure sits close to the 267mg this site’s own Peet’s breakdown found in a 16oz drip coffee, though Costa does not publish the filter line’s sizes in fluid ounces, so an exact ounce-for-ounce match is not possible from the available data. Costa does not publish specific decaf figures either; this site’s own decaf coffee breakdown documents a 2 to 15mg range as typical for commercial decaf across the chains that do publish a number, and there is no reason to expect Costa’s decaf to fall meaningfully outside that band.

The under-16 policy: a strong pour with an age check attached

Costa became the first major UK coffee chain to let stores decline to sell caffeinated drinks to customers under 16, a policy that started in the summer of 2018 and drew wide coverage that November after a store in North Wales turned away a 12-year-old ordering an iced coffee. Costa’s own stated position, per TODAY.com’s reporting, is: “We do not encourage the sale of caffeine to children under 16 and it is at store discretion to question a customer’s age if they have any concerns.” The policy is discretionary rather than a hard rule, so enforcement varies store to store and staff member to staff member.

TODAY.com’s coverage also cites the American Academy of Pediatrics’ recommendation that children and teens aged 12 to 18 consume no more than 100mg of caffeine a day. A single medium Costa cappuccino, at 325mg, is more than three times that daily figure in one cup, which puts the chain’s own age-check policy in a different light: it is not a symbolic gesture layered onto an ordinary cup of coffee, it is attached to menu items that genuinely can carry more caffeine per serving than almost anything else sold at a UK coffee counter.

Worked example: hitting a specific caffeine target at Costa

1. Start from the shot, not the cup size. A single espresso shot is 100mg, and Costa scales almost everything from there: small equals two shots, medium equals three, large equals four, per Caffeine Informer’s figures.
2. Expect a cappuccino or americano to hit 325mg at medium. That already exceeds MD Anderson Cancer Center’s cited FDA guidance that most healthy adults should stay under about 400mg a day, in a single cup.
3. Drop to a latte for a lighter dose at the same size label. A medium latte runs 200mg, one shot lighter than a medium cappuccino or americano, per Costa’s own published shot counts.
4. Treat the flat white as its own category. At 241mg, it does not follow the shot-doubling pattern the rest of the menu uses, since Costa’s blog cites a different extraction method for that specific drink.
5. Reach for filter coffee over cold brew for a closer-to-drip experience. Filter coffee runs 192 to 320mg across sizes; cold brew runs lower per size at 160 to 210mg, per Caffeine Informer’s figures.
6. If you’re building a home setup that can pull a genuinely strong shot, the shot-driven strength Costa’s menu relies on comes down to a machine that can pull consistent, repeatable espresso, whether from 1st in Coffee’s espresso machine range or on Amazon.

How Costa stacks up against the US chains this site has measured

Comparing chains fairly means comparing caffeine per fluid ounce, since a “medium” is not the same pour everywhere, and normalizing to a 16 fl oz size where each chain publishes one. Costa’s closest match is its medium americano, the one Costa drink Caffeine Informer lists at exactly 16 fl oz: 325mg. Worth flagging directly: an americano is espresso diluted with hot water, not drip-brewed coffee, so this is the closest available comparison point across all seven chains rather than a perfect apples-to-apples match.

Costa’s medium americano edges out even Starbucks’ Grande Pike Place on a per-ounce basis, making it the strongest pour of any chain this site has measured to date, US or UK.

Common mistakes

Assuming Costa’s caffeine works like an American drip chain’s is the most common mistake; Costa’s menu scales almost entirely by shot count, two, three, or four shots depending on size, rather than by diluting a fixed espresso base the way Panera’s lattes do. Assuming the flat white follows the same doubling pattern as the rest of the menu is the second mistake; at 241mg it sits outside the 200/325/400mg progression the rest of Costa’s espresso drinks follow, per Caffeine Informer’s figures. Assuming Costa’s caffeine content changed because of a recipe update is the third mistake; per The Caterer’s 2023 figures and the Irish Times’ 2026 figures, Costa’s own cappuccino number has held at 325mg across both tests, while Starbucks and Greggs both moved upward in between. Treating the under-16 policy as symbolic is the fourth mistake; a single medium cappuccino at Costa carries more than three times the American Academy of Pediatrics’ recommended daily teen caffeine limit, per TODAY.com’s reporting, in one cup.

Common questions

How much caffeine is in a Costa Coffee cappuccino? 325mg in a medium cup, per Caffeine Informer’s figures and an August 2026 Which? test, almost three and a half times Starbucks’ 89mg at the same size, per the Irish Times’ reporting on that study.

Why does Costa have more caffeine than Starbucks? Costa’s menu scales by shot count, a fixed 100mg per shot with small, medium, and large drinks getting two, three, and four shots respectively, per Caffeine Informer, rather than by the size-driven dilution pattern other chains use.

Has Costa’s caffeine content changed recently? No. The Caterer’s report on a 2023 Which? test and the Irish Times’ report on the August 2026 test both put Costa’s medium cappuccino at 325mg. Starbucks and Greggs both increased in the same period, which is why the gap between Costa and its competitors narrowed rather than Costa getting stronger.

Does Costa really refuse to sell coffee to people under 16? Stores can, at their own discretion. Costa’s stated policy, per TODAY.com, is that staff are not required to sell caffeinated drinks to anyone under 16 and can question a customer’s age if concerned, a policy that started in 2018 and remains discretionary rather than mandatory.

How much caffeine is in a Costa flat white? 241mg for a medium, per Caffeine Informer and the August 2026 Which? test, more than double Starbucks’ 89mg flat white at a comparable size. It does not follow Costa’s usual shot-doubling pattern because of a different extraction method used for that drink.

Is Costa’s coffee stronger than every US chain this site has measured? Yes, on a per-ounce basis. Costa’s medium americano works out to about 20.3mg of caffeine per fluid ounce against Starbucks’ Grande Pike Place at about 19.4mg, the next strongest pour this site has measured among US chains.

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Written by Theo Marsh · Published 29 September 2026