How much caffeine is left in your body from up to three doses, based on its half-life, and when the level drops below an amount you choose.
പുതുക്കിയത് പരിശോധിച്ച ഉദാഹരണങ്ങൾ: 5
At 22:00 about 45 mg of the 221 mg you had is still in your body. With a 5-hour half-life it drops below 50 mg at 21:15, 7 h 14 min after the last dose.
Times are hours after the first dose at 08:00; doses after the check time are left out.
Rounded up to the next whole minute.
Each dose is assumed to enter the body at once and then halve every half-life: the amount left from a dose is dose × 0.5^(hours since the dose ÷ half-life), and the calculator adds up to three doses. It also works out when the total falls below a level you choose, using time = half-life × log2(level after the last dose ÷ chosen level).
People use it to decide when to stop drinking coffee before bed. With the defaults, 150 mg at 08:00 and a 71 mg black tea at 14:00 leave about 45 mg at 22:00, and the level has been below 50 mg since 21:15.
The default half-life of 5 hours is the average for healthy adults, but it ranges from about 1.5 to 9.5 hours and changes with pregnancy, oral contraceptives and smoking. Blood levels actually peak 15 to 120 minutes after drinking, so the curve overstates the level in the first hour or two after each dose.
പരിശോധനയുടെ ഉറവിടം: Python 3.8 decimal: 200 × 0.5^(10/5) = 50; threshold reached at 5 × log2(200/50) = 10 h
പരിശോധനയുടെ ഉറവിടം: Python 3.8 decimal: 95·0.5^(14/5) + 64·0.5^(9/5) = 32.01997; 13:00 + 5·log2(111.5/50) h = 18:47:08, rounded up to 18:48
പരിശോധനയുടെ ഉറവിടം: Python 3.8 decimal: 150 × 0.5^(6/5) = 65.2913; 5·log2(3) = 7.9248 h after 20:00 = 03:55:25, rounded up
പരിശോധനയുടെ ഉറവിടം: Python 3.8 decimal: 40 × 0.5^(3/5) = 26.3902; 40 mg ≤ 50 mg from the start
With the average 5-hour half-life, half of a dose is still in your body after 5 hours, a quarter after 10 and about 3% after 25, so 200 mg of coffee at 08:00 leaves 50 mg at 18:00. Half-lives in healthy adults range from about 1.5 to 9.5 hours (Antonio et al., Journal of the International Society of Sports Nutrition, 2024), so the same cup can last several times longer in one person than in another.
For most healthy adults the FDA cites 400 mg a day, about two to three 12 fl oz cups of brewed coffee, as an amount not generally associated with negative effects. The FDA estimates that toxic effects such as seizures can appear after rapidly consuming about 1,200 mg. The calculator warns when the doses you enter add up to more than 400 mg.
At least 8.8 hours for a 107 mg cup of coffee and 13.2 hours for a 217.5 mg pre-workout drink, according to a 2023 meta-analysis of 24 studies in Sleep Medicine Reviews (Gardiner et al.). Across those studies caffeine cut total sleep by 45 minutes and added 9 minutes to the time taken to fall asleep. In an earlier trial, 400 mg taken 6 hours before bed still disrupted sleep (Drake et al., 2013).
The FDA gives 113 to 247 mg for 12 fl oz of brewed coffee, 71 mg for black tea, 37 mg for green tea, 23 to 83 mg for soft drinks and 41 to 246 mg for energy drinks of the same size; 8 fl oz of decaf has 2 to 15 mg. Brewing method and cup size change the dose, so use the label figure where there is one.
Less than 200 mg a day. The American College of Obstetricians and Gynecologists' Committee Opinion 462 states that intake below 200 mg a day does not appear to be a major contributing factor in miscarriage or preterm birth. Caffeine is also cleared more slowly: one study measured a mean half-life of 8.3 hours in pregnant women against 3.4 hours in other adults (Knutti et al., 1981), so a longer half-life gives a more realistic curve.
കൃത്യത നിങ്ങളുടെ ഇൻപുട്ടുകളെയും രീതിയുടെ അനുമാനങ്ങളെയും ആശ്രയിച്ചിരിക്കുന്നു. ദശാംശ ഗണിതം 50 സാർഥക അക്കങ്ങൾ ഉപയോഗിക്കുന്നു. എന്നാൽ അനുമാനക്കണക്കുകൾ, സംഖ്യാത്മക രീതികൾ, ഉറവിട ഡാറ്റ എന്നിവയ്ക്ക് കൃത്യത കുറവാകാം; പ്രദർശിപ്പിക്കുന്ന മൂല്യം റൗണ്ട് ചെയ്യുന്നത് ഈ പരിമിതികൾ നീക്കില്ല. സ്വതന്ത്ര ഉറവിടങ്ങളിലെ പരിഹാരങ്ങളുമായി പരിശോധിച്ച ഉദാഹരണങ്ങൾ: 5. ഉദാഹരണത്തിന്, “200 mg at 08:00, checked at 18:00 (two half-lives)” എന്നത് Python 3.8 decimal: 200 × 0.5^(10/5) = 50; threshold reached at 5 × log2(200/50) = 10 h ഉപയോഗിച്ച് പരിശോധിക്കുന്നു.
Institute of Medicine (US) Committee on Military Nutrition Research. Caffeine for the Sustainment of Mental Task Performance (2001) — pharmacology of caffeine; FDA — Spilling the beans: how much caffeine is too much?; Antonio J et al. Common questions and misconceptions about caffeine supplementation. J Int Soc Sports Nutr 2024;21:2323919 (mean half-life about 5 h, range 1.5–9.5 h); Gardiner C et al. The effect of caffeine on subsequent sleep: a systematic review and meta-analysis. Sleep Med Rev 2023;69:101764.
വിവരത്തിന് മാത്രം, വൈദ്യോപദേശമല്ല. ഈ സൂത്രങ്ങൾ ജനസമൂഹങ്ങളെ വിവരിക്കുന്നു, നിങ്ങളുടെ വ്യക്തിഗത അവസ്ഥയെയല്ല; ഫലത്തെ അടിസ്ഥാനമാക്കി പ്രവർത്തിക്കുന്നതിന് മുമ്പ് ആരോഗ്യവിദഗ്ധനുമായി സംസാരിക്കുക.
ഈ കാൽക്കുലേറ്ററിൽ സ്വതന്ത്ര ആധാരങ്ങളിൽ നിന്ന് ഉത്തരങ്ങൾ ലഭിച്ച 5 പരിഹരിച്ച ഉദാഹരണങ്ങളുണ്ട്. ഇവ പരിശോധനാസമുച്ചയത്തിൽ പ്രവർത്തിക്കുന്നു; നിങ്ങൾക്ക് ഇവിടെയും പ്രവർത്തിപ്പിക്കാം.
Bedtimes for a wake-up time, or wake-up times for a bedtime, counted in 90-minute sleep cycles plus the time it takes to fall asleep.
Blood alcohol content (BAC) estimate by the Widmark formula from drinks, body weight and time, with the elimination curve and time back to zero.
Daily water intake in litres, glasses and fl oz from body weight, exercise and climate, compared with EFSA and US adequate intakes.