Caffeine Calculator – Daily Caffeine Intake and Half-Life (mg)
Use this free caffeine calculator to add up the caffeine in your coffee, tea, energy drinks and pre-workout. See your daily total against commonly used limits, and use the caffeine calculator half life check to estimate how much could still be in your system at bedtime.
Caffeine intake calculator
Enter how many you have in a day. Caffeine amounts are typical averages and vary by brand, size and brewing.
Add a product from its label
Bedtime check
Enter your drinks and press calculate.
How much caffeine is too much?
Many health authorities, including Health Canada and the European Food Safety Authority, suggest healthy adults can consume up to about 400 mg of caffeine a day without safety concerns. Pregnant and breastfeeding women are commonly advised to limit intake to about 200 mg a day, and adolescents to lower amounts, around 2.5 mg per kg of body weight. Individual sensitivity varies a lot, and some people feel jittery or sleep poorly at much lower doses.
Worked example: two café coffees (2 × 80 mg), one can of cola (36 mg) and one pre-workout scoop (200 mg) total 396 mg, right at the adult limit. If the last dose was 8 hours before bed and the half-life is 5 hours, about 396 × 0.5^(8/5) = 131 mg would remain.
Typical caffeine content of drinks
| Item | Approximate caffeine |
|---|---|
| Instant coffee, 250 mL cup | 80 mg |
| Café coffee, 1 shot espresso | 80 mg |
| Black tea, 250 mL cup | 40 mg |
| Green tea, 250 mL cup | 30 mg |
| Matcha, 1 tsp (2 g) | 35 mg |
| Cola, 375 mL can | 36 mg |
| Energy drink, 250 mL | 80 mg |
| Dark chocolate, 30 g | 20 mg |
Caffeine content is regulated for energy drinks in Australia, but coffee varies widely between cafés, bean types and cup sizes.
Caffeine in coffee
Caffeine in coffee varies with the bean, brew method and cup size. A café flat white or latte with one shot has roughly 80 mg, a double shot about 160 mg, and an instant coffee about 80 mg. Use the table above as a guide.
Caffeine, sleep and training
Caffeine has a half-life of roughly five hours in most healthy adults, so an afternoon coffee can still be affecting you at bedtime. If you use a pre-workout, check its caffeine per serve and count it in your daily total. Browse pre-workout products, coffee, matcha drinks, or choose caffeine-free drinks later in the day.
Frequently asked questions
How much caffeine is in a cup of coffee?
An instant coffee has about 80 mg and a café espresso shot about 80 mg, but it varies by size and brew method.
How much caffeine can I have a day?
Up to about 400 mg a day is commonly considered safe for healthy adults. Pregnant or breastfeeding women are usually advised to stay below about 200 mg.
What is the half-life of caffeine?
About five hours for most adults, but it can range from roughly three to seven hours depending on genetics, medications, smoking and pregnancy.
When should I stop drinking caffeine to sleep well?
Many people sleep better if they stop caffeine six to eight hours before bed. Try the bedtime check above to see what may remain.
Does decaf have caffeine?
Yes, a small amount, typically 2 to 15 mg per cup.
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General information only, not medical advice. People with heart conditions, anxiety, high blood pressure, sleep problems, or who are pregnant or taking medication should speak to a doctor about caffeine.