Free tool · Nutrition
Pre-workout caffeine calculator
Short answer
Caffeine has consistently improved exercise performance at 3–6 mg per kg of body weight, most often taken about 60 minutes before. At 70 kg that is 210–420 mg, and as little as 2 mg/kg (140 mg) may work. Very high doses, around 9 mg/kg, bring more side effects without more benefit.
Last reviewed 28 October 20263 published sourcesNot medical advice
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The dose range that has helped exercise performance in studies, scaled to your body weight.
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| Body weight | 2 mg/kg | 3 mg/kg | 6 mg/kg |
|---|---|---|---|
| 50 kg (110 lb) | 100 mg | 150 mg | 300 mg |
| 60 kg (132 lb) | 120 mg | 180 mg | 360 mg |
| 70 kg (154 lb) | 140 mg | 210 mg | 420 mg (over 400 mg) |
| 80 kg (176 lb) | 160 mg | 240 mg | 480 mg (over 400 mg) |
| 90 kg (198 lb) | 180 mg | 270 mg | 540 mg (over 400 mg) |
| 100 kg (220 lb) | 200 mg | 300 mg | 600 mg (over 400 mg) |
What the research says
The ISSN position stand finds caffeine consistently improves exercise performance at 3–6 mg/kg, with aerobic endurance showing the most consistent benefit. The minimal effective dose may be as low as 2 mg/kg, the most common timing is 60 minutes before, and very high doses (about 9 mg/kg) bring a high rate of side effects (Guest et al., 2021 (ISSN)).
For healthy adults the FDA cites 400 mg a day as an amount not generally associated with negative effects (U.S. FDA), and EFSA sets 200 mg a day in pregnancy (EFSA, 2015). Add up your whole day with the daily caffeine calculator and find your last-coffee time with the caffeine calculator.
Caffeine that doesn't cost you sleep
Reps tracks the caffeine you log and tells you when to stop for the day so it is mostly gone by bedtime.
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Common questions
How much caffeine should I take before a workout?
Studies show benefits at 3–6 mg per kg of body weight, and possibly from 2 mg/kg. Start at the low end; more is not better.
When should I take caffeine before exercise?
Most studies give it about 60 minutes before. Caffeine gum may need less time than capsules.
Is a pre-workout dose safe with my morning coffee?
Count both toward the 400 mg a day that the FDA says is not generally associated with negative effects in healthy adults. During pregnancy, EFSA's limit is 200 mg a day. A late workout dose can also cut into your sleep.
Sources
Figures on this page were checked against these publications on 28 October 2026.
- Guest NS, VanDusseldorp TA, Nelson MT, Grgic J, Schoenfeld BJ, Jenkins NDM, Arent SM, Antonio J, Stout JR, Trexler ET, Smith-Ryan AE, Goldstein ER, Kalman DS, Campbell BI. International society of sports nutrition position stand: caffeine and exercise performance. Journal of the International Society of Sports Nutrition. 2021;18:1. doi.org/10.1186/s12970-020-00383-4
- U.S. Food and Drug Administration. Spilling the Beans: How Much Caffeine is Too Much? Consumer Update (content current as of 28 August 2024). www.fda.gov/consumers/consumer-updates/spilling-beans-how-much-caffeine-too-much
- EFSA Panel on Dietetic Products, Nutrition and Allergies. Scientific Opinion on the safety of caffeine. EFSA Journal. 2015;13(5):4102. doi.org/10.2903/j.efsa.2015.4102
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