A UK mug of filter coffee carries roughly 95 to 200 mg of caffeine, an espresso shot 60 to 80 mg, a mug of tea 30 to 75 mg, and a cup of decaf 2 to 15 mg. The exact figure depends on brew method, bean type and, for decaf, how the coffee was decaffeinated.
That is the short answer. The longer answer matters because most of the caffeine figures floating around online use a US 8 oz cup (240 ml), and most UK readers are pouring into a 250 to 300 ml mug. So the headline number you see in a Mayo Clinic table is already understating what is actually in your hand by 5 to 25 per cent before brew method or roast come into it.
This is the UK drink-by-drink version, with the decaf piece worked out by decaffeination method rather than left as a single vague range.
Caffeine mg per cup by drink (UK serving sizes)
A typical UK mug is 250 to 300 ml, an espresso shot is 30 ml, a flat white is 150 to 180 ml, and a takeaway “regular” from the high street is 350 ml. Caffeine per drink looks like this.
| Drink | Typical UK serving | Caffeine (mg) |
|---|---|---|
| Filter coffee | 240 ml mug | 115 to 175 (avg ~145) |
| French press / cafetière | 240 ml | 70 to 140 |
| Espresso, single | 30 ml | 60 to 80 |
| Espresso, double | 60 ml | 130 to 160 |
| Flat white | 150 to 180 ml | ~130 (2 shots) |
| Latte (1 shot) | 240 ml | 60 to 80 |
| Cappuccino (1 shot) | 180 ml | 60 to 80 |
| Americano (2 shots) | 240 ml | 130 to 160 |
| Instant coffee | 200 ml mug | 60 to 100 |
| Cold brew | 240 ml | 100 to 200 |
| Black tea | 200 ml mug | 45 to 75 |
| Green tea | 200 ml mug | 30 to 50 |
| White tea | 200 ml | 15 to 30 |
| Herbal tea | 200 ml | ~0 |
| Decaf coffee | 200 to 240 ml | 2 to 15 |
| Decaf tea | 200 ml | ~2 |
| Cola | 330 ml can | ~40 |
| Energy drink | 250 ml can | ~80 |
Sources for the ranges: Farrer’s (240 ml filter brew), Healthline, BBC Good Food, NHS pregnancy guidance, and the British Heart Foundation. Where two reputable sources disagreed, the table shows the range rather than picking a single figure with false precision. Mayo Clinic does the same thing for the same reason.
Why caffeine per cup varies so much
Brew method does most of the heavy lifting. Filter coffee uses gravity over several minutes and pulls more caffeine out per gram of grounds. Espresso uses pressure over 25 to 30 seconds, which is why a shot is small but only moderately caffeinated. Cold brew often comes in higher than hot drip because it uses around 1.5 times the grounds of a standard hot brew.
Grind size feeds into the same equation. Finer grind means more surface area exposed to water, which means more caffeine extracted per gram of grounds. The water to coffee ratio does the obvious thing on top of that, which is why a strong pour scoops more coffee in.
Bean type matters too. Robusta beans carry roughly twice the caffeine of Arabica by weight. Most UK speciality coffee is Arabica. A lot of UK supermarket instant blends in Robusta, which is part of why a strong mug of instant can read closer to a filter brew than the price suggests.
Roast level is the counter intuitive one. Lighter roasts carry slightly more caffeine than darker roasts because the longer roast breaks more of the molecule down. By volume scoop the difference is small because dark beans are less dense, but by weight light roasts win on caffeine. The “stronger tasting equals more caffeine” instinct is unreliable.
Caffeine in decaf coffee, by decaffeination method
This is the part most published guides skim over. “Decaf has 2 to 15 mg per cup” is technically true and editorially lazy, because the residual depends on how the coffee was decaffeinated, not whether.
The EU requires decaf to be at least 99.9 per cent caffeine free by mass on the green bean. The US requires 97 per cent. So no decaf is zero. The interesting question is how cleanly each method gets to that threshold.
Swiss Water decaf. Water, temperature, time and activated carbon. No organic solvents touch the bean. Swiss Water guarantees the 99.9 per cent figure and one published comparison (Talking Crow Coffee Roasters) measured 1.8 mg per cup against 5.4 mg for non Swiss Water decaf. The flavour bias is clean and chocolate leaning.
Sugar cane / ethyl acetate decaf. Naturally derived ethyl acetate, often produced from sugar cane fermentation in Colombia, bonds with caffeine and is rinsed off. The “natural solvent” framing is real (ethyl acetate occurs in fruit), and the residuals sit at a comparable level to Swiss Water. Often processed at origin, which keeps more value with the producer country.
Supercritical CO2. Pressurised liquid carbon dioxide selectively binds caffeine and is then vented off. Capital intensive, specialty grade, retains slightly more body and lipids than Swiss Water. The default choice for specialty espresso decaf.
Chemical / methylene chloride decaf. Solvent applied directly or indirectly to beans. Meets the same regulatory thresholds and, according to industry chemists, preserves the original flavour compounds slightly better than the alternatives. Specialty roasters avoid it because of the perception risk attached to MC residue, even at the heavily regulated levels permitted (FDA limit 10 ppm, real residue typically around 0.1 ppm).
If you want the lowest residual caffeine and the cleanest chemistry, look for Swiss Water or sugar cane EA. Both clear the EU 99.9 per cent bar by design, and neither involves a synthetic solvent touching the bean.
What counts as a “cup” in the UK
A US cup is 240 ml, which is the unit most published caffeine figures use. A typical UK home mug is 250 to 300 ml. So Mayo Clinic’s “95 mg per cup” is already 5 to 25 per cent shy of what your actual mug pour delivers.
| Serving | Volume (ml) |
|---|---|
| Espresso shot | 30 |
| NHS reference mug | 200 |
| US cup (8 fl oz) | 240 |
| UK home mug | 250 to 300 |
| UK Imperial cup | 284 |
| Takeaway regular (UK chain) | 350 |
| Takeaway large (UK chain) | 470 |
The NHS uses 200 ml as a deliberately conservative reference figure in pregnancy guidance. If you are tracking daily intake against the EFSA or NHS ceilings, default to your actual mug volume rather than the official mug.
Safe daily caffeine in the UK
EFSA’s 2015 scientific opinion sets 400 mg of caffeine over 24 hours as the safe ceiling for healthy adults, and 200 mg as the ceiling in pregnancy. EFSA also flags that a single dose of 100 mg, taken close to bedtime, can lengthen sleep latency and reduce sleep duration. NHS pregnancy guidance aligns at 200 mg per day, citing risks of low birthweight and miscarriage above that.
Translated into actual drinks (using the table above, NHS per mug figures for consistency):
- 400 mg a day is about three mugs of filter coffee, four mugs of instant, five double espressos, five mugs of tea, or around 26 cups of decaf at the upper 15 mg estimate (closer to 57 cups at the BHF 7 mg figure).
- 200 mg in pregnancy is about one and a half mugs of filter, two mugs of instant, two and a half mugs of tea, or two 250 ml cans of energy drink.
Worth a sanity check against actual habits. Three takeaway lattes (each closer to 350 ml and effectively a double shot) plus a cup of black tea is already past 400 mg before you have noticed.
Caffeine in tea vs coffee
Mug for mug, coffee carries roughly twice the caffeine of tea. A 200 ml mug of black tea sits around 45 to 75 mg, green tea around 30 to 50 mg, white tea lower again at 15 to 30 mg, and herbal teas (rooibos, peppermint, chamomile) effectively zero. Matcha is the outlier, with a half teaspoon (about 1 g) carrying 18 to 44 mg, which is high for the volume.
Steep time matters more for tea than brew time matters for filter coffee. A 3 minute steep on black tea roughly triples the caffeine of a 1 minute steep, because the rate of caffeine extraction is much steeper in the first few minutes.
A strong long steeped black tea can land at the lower end of a small instant coffee, which is why the “tea is always lighter than coffee” rule of thumb is broadly true but not absolute.
Where to go from here
If you want to drink coffee without the caffeine load, the practical answer is to switch to a Swiss Water decaf or sugar cane EA decaf and stop worrying about residuals. Both remove more than 99.9 per cent by mass and both keep solvents off the bean.
Browse the full directory and filter by decaffeination method to see every UK decaf coffee we list, ranked by method, origin and price. If you want the curated version with new arrivals as they land, the Decaffeinate Club covers that.
Sources for figures in this article: EFSA Scientific Opinion 2015 (caffeine safety), NHS pregnancy guidance, Mayo Clinic caffeine content article, Healthline brew method breakdown, British Heart Foundation decaf comparison, and Farrer’s Coffee UK brew data.