Caffeine calculator

Add what you've drunk today to see your total, how much caffeine will still be in your body at bedtime, and the latest time for your next coffee. Includes Costa, Starbucks, Pret, Caffè Nero, Greggs, Red Bull and Monster.

Ashwagandha & Lions Mane Mushroom - Nootropic Brain Supplement

Calm focus, without more caffeine

Our Ashwagandha + Lion's Mane capsules contain no caffeine.

See Ashwagandha + Lion's Mane

Caffeine in UK drinks

Typical amounts from the NHS, the European Food Safety Authority, Which? (2026) and the brands. Brews, cup sizes and recipes vary, so treat these as a guide.

Drink Serving Caffeine
Instant coffee 1 mug 100 mg
Filter coffee 1 mug 140 mg
Espresso 1 single shot 80 mg
Costa cappuccino Medium 325 mg
Costa Americano Medium 325 mg
Costa flat white Medium 241 mg
Costa latte Medium 200 mg
Pret filter coffee 355 ml 271 mg
Pret latte or cappuccino 355 ml 180 mg
Starbucks Pike Place filter Tall 210 mg
Starbucks Americano Grande 134 mg
Starbucks latte or cappuccino Tall 89 mg
Caffè Nero cappuccino Regular 221 mg
Caffè Nero latte Regular 175 mg
Greggs Americano Large 257 mg
Greggs latte Large 208 mg
Decaf coffee
Decaf still has a little caffeine.		 Costa, medium 2 mg
Black or green tea 1 mug 75 mg
Matcha 1 teaspoon (2 g) 68 mg
Costa matcha latte Medium 99 mg
Starbucks English Breakfast tea Tall 41 mg
Cola 330 ml can 40 mg
Coca-Cola 330 ml can 34 mg
Diet Coke 330 ml can 46 mg
Red Bull 250 ml can 80 mg
Monster Energy 500 ml can 160 mg
Plain chocolate
Less than this, says the NHS.		 50 g bar 25 mg
Starbucks hot chocolate Tall 20 mg

Sources are listed below.

How the calculator works

Caffeine is absorbed over about 45 minutes, then your body clears it at a steady rate: about half every 5 hours for most adults, though this ranges from about 3 to 7 hours. Smoking speeds it up, while the contraceptive pill roughly doubles it and pregnancy slows it further, so the calculator offers a faster and a slower setting.

The bedtime level comes from a 2023 review of sleep studies, which found that a regular coffee finished 8.8 hours before bed no longer cut into sleep. That coffee leaves about 30 mg by bedtime, so the calculator uses 30 mg as the most you'd want left. These are averages, not a medical test: some people sleep well after an evening espresso and others don't.

Sources

  1. NHS. Foods to avoid in pregnancy: caffeine. nhs.uk
  2. Food Standards Agency. Caffeine and pregnancy. food.gov.uk
  3. EFSA Panel on Dietetic Products, Nutrition and Allergies (2015). Scientific opinion on the safety of caffeine. EFSA Journal 13(5):4102.
  4. Gardiner C, Weakley J, Burke LM, et al. (2023). The effect of caffeine on subsequent sleep: a systematic review and meta-analysis. Sleep Medicine Reviews 69:101764.
  5. Drake C, Roehrs T, Shambroom J, Roth T (2013). Caffeine effects on sleep taken 0, 3, or 6 hours before going to bed. Journal of Clinical Sleep Medicine 9(11):1195–1200.
  6. Temple JL, Bernard C, Lipshultz SE, et al. (2017). The safety of ingested caffeine: a comprehensive review. Frontiers in Psychiatry 8:80.
  7. Grzegorzewski J, Bartsch F, Köller A, König M (2022). Pharmacokinetics of caffeine: a systematic analysis of reported data for application in metabolic phenotyping and liver function testing. Frontiers in Pharmacology 12:752826.
  8. Nehlig A (2018). Interindividual differences in caffeine metabolism and factors driving caffeine consumption. Pharmacological Reviews 70(2):384–411.
  9. Which? (25 August 2026). Caffeine levels in high street coffees still vary significantly, Which? finds. Figures from the chains, checked 19 August 2026.
  10. Which? (3 October 2025). What is matcha?
  11. Starbucks UK. Nutrition information, September to November 2026.
  12. Red Bull GB; Coca-Cola Great Britain, frequently asked questions; Monster Energy UK can label (32 mg per 100 ml).

Read next

L-theanine: what it does, and how it compares with ashwagandhaWhat L-theanine is, what the research shows for focus, stress and sleep, how much to take, and how it compares with ashwagandha. Magnesium for sleep: what the research showsDoes magnesium help you sleep? What the trials show, which form to choose, how much to take and when, with NHS guidance on safe... What are nootropics? A UK guideWhat nootropics are, which ones have real evidence behind them, what UK law says and how to choose a supplement.

Caffeine questions

Short answers, based on NHS guidance and published research.

Does matcha have caffeine?

Yes. Matcha is whole green tea leaf ground to a powder, so you drink all of its caffeine. Which? found about 68 mg in a 2 g teaspoon of ceremonial-grade matcha, a little less than a mug of instant coffee. Coffee shop matcha lattes ranged from 28 mg to 99 mg.

How much caffeine is in a cup of coffee?

The NHS puts a mug of instant coffee at about 100 mg and a mug of filter coffee at about 140 mg. Coffee shop drinks vary far more: in 2026 Which? found about 325 mg in a medium Costa cappuccino and about 89 mg in a tall Starbucks latte.

Does green tea have caffeine?

Yes. The NHS puts a mug of black or green tea at about 75 mg of caffeine, a little less than a mug of instant coffee. Matcha, a powdered green tea, has about 68 mg in a teaspoon.

How much caffeine is in tea?

A mug of black or green tea has about 75 mg of caffeine, according to the NHS. How long you brew it makes a difference, and coffee shop teas can have less: Starbucks lists 41 mg for a tall English Breakfast tea.

How long does caffeine stay in your system?

Most adults clear half the caffeine in a drink in about 5 hours, though it ranges from about 3 to 7 hours. So a 100 mg coffee at 3pm still leaves around 50 mg at 8pm and 25 mg at 1am. Smoking speeds this up, the contraceptive pill roughly doubles it, and it slows further in pregnancy.

Does tea have more caffeine than coffee?

Not by the mug. A mug of tea has about 75 mg, compared with about 100 mg for instant coffee and 140 mg for filter coffee. Tea leaves hold more caffeine than coffee beans by weight, but a cup of tea uses far less of them.

Does decaf coffee have caffeine?

A little. Decaf isn't caffeine-free: Costa's decaf has about 2 mg and Pret's decaf latte about 6 mg, against 100 mg or more in a regular coffee.

Does peppermint tea have caffeine?

No. Peppermint tea is made from peppermint leaves rather than the tea plant, so it's naturally caffeine-free. Blends that mix peppermint with green or black tea do contain some caffeine.

Does chai latte have caffeine?

Usually, yes. Chai is spiced black tea, so a chai latte has some caffeine, typically less than a coffee. Powders and syrups vary a lot, so check the brand. Caffeine-free versions use rooibos instead of tea.

How much caffeine is too much in a day?

The European Food Safety Authority says up to 400 mg a day is safe for healthy adults, with up to 200 mg at a time. That's about four mugs of instant coffee. In pregnancy the NHS limit is 200 mg a day.