The short answer: a little, not a lot
Playing chess burns calories the same way reading, typing or watching a tense film does: slightly more than doing nothing.
Exercise scientists measure activity in METs (metabolic equivalents). One MET is the energy you use sitting quietly, defined as about 1 kilocalorie per kilogram of body weight per hour (Ainsworth et al., 2011). The 2024 Adult Compendium of Physical Activities, the standard reference used by researchers, lists a sitting chess game at 1.5 METs (code 09013). Card games are also 1.5; general board games are 1.3.
So chess burns about 50% more than sitting still. That sounds like a lot until you put real numbers on it: for a 70 kg (154 lb) adult, sitting quietly burns about 70 kcal an hour and chess about 105. The difference is roughly 35 kcal an hour.
Chess is mentally exhausting. It is not physically demanding. Those are different things, and confusing them is how the myth started.
Chess compared with other activities
Here is chess on the same scale as some everyday activities, using the Compendium’s MET values:
METs from the 2024 Adult Compendium of Physical Activities (codes 07021, 09000, 09013, 15080, 17190, 15690). Bar length is proportional to METs.
Put another way: in extra calories over sitting still, one hour of singles tennis equals about 14 hours of chess.
Calculator: how many calories does your chess burn?
Estimate: METs × body weight in kg × hours. Real energy use varies from person to person; this is a population average, not a measurement of you.
What studies have actually measured
The Compendium value is an average. Two studies have measured chess players directly, using indirect calorimetry (breathing into a mask that analyses oxygen and carbon dioxide), which is the standard method for measuring energy use.
Troubat et al. (2009): about 1.5 kcal per minute
French researchers measured 20 male club and tournament players (average rating about 1757) during a game against a computer set slightly above their level, with an hour on the clock each (European Journal of Applied Physiology, 2009). Their findings:
- Energy use was about 1.53 kcal per minute both before the game (seated) and through it, with no significant change. That is about 92 kcal an hour, close to the Compendium estimate.
- A whole game, lasting around 90 minutes, cost on average 138 kcal (range 102–198).
- Heart rate did rise, from about 75 to 86 beats per minute by the end of the game, and the body shifted from burning carbohydrate towards burning fat. Those are signs of stress, not of hard physical work.
Rodoplu et al.: chess vs running
A Turkish study of 24 regular players compared a competitive game with a session of moderate running and found that the running cost significantly more energy (Baltic Journal of Sport and Health Sciences). The authors had expected the two might be similar; they were not.
Neither study came anywhere near the numbers in the viral claim.
Where the “6,000 calories a day” claim came from
The claim that grandmasters burn up to 6,000 calories a day during tournaments went viral after a 2019 ESPN feature, which quoted Stanford neuroscientist Robert Sapolsky. From there it spread to podcasts, magazines and social media. When people traced it back, it fell apart:
- The original data. In the 1970s, researchers at Temple University measured breathing, blood pressure and muscle tension in 11 amateur players rated 1329–1921. None were grandmasters, and no one measured calories.
- “Breathing triples.” Breathing rates briefly peaked above 40 breaths a minute from a resting rate of about 14. That is a short maximum, not an average; the average increase during games was about 14–18%.
- The multiplication. The 6,000 figure appears to come from multiplying that “tripling” by a typical 2,000-calorie daily intake: 3 × 2,000 = 6,000. Breathing rate does not translate into calories like that.
- Repetition. The number was repeated without checking until metabolism researcher Adam Strandberg traced it in 2025 (his write-up); statistician Andrew Gelman called it a bogus claim (his blog).
The arithmetic check
To burn 6,000 kcal in a day, a 70 kg person would need to average 3.6 METs for all 24 hours, roughly the effort of walking at a moderate pace (3.8 METs) nonstop, day and night, without sleeping. Chess, at 1.5 METs for a few hours, does not come close.
A related figure, that a grandmaster burned 560 calories in two hours of play, came from a heart-rate monitor. Wearables estimate calories from heart rate, and stress raises heart rate without much extra physical work, so these estimates tend to run high in tense, seated activities like chess.
Then why do chess players lose weight during tournaments?
Players and coaches do report losing weight during long events; the ESPN feature described several top players doing so. That can be true even though the chess itself burns little. The more likely reasons are ordinary ones:
- Stress and nerves reduce appetite, and many players eat less on game days.
- Irregular meals and sleep: games that last five or six hours, late finishes and preparation for the next round get in the way of normal routines.
- Travel, unfamiliar food and long days.
- Water: some short-term weight change is fluid, not fat.
None of this has been measured in a controlled way for elite players, so treat it as the likely explanation rather than a proven one. What we can say is that eating less and sleeping badly, not burning thousands of calories at the board, is a far better fit for the data we have.
Stress is not exercise
The confusion comes from a real effect. A tense chess game does trigger a stress response: heart rate rises, breathing changes, stress hormones go up. Troubat’s players showed exactly that. But your body can go into “fight or flight” mode without actually fighting or fleeing. The muscles that burn most of your energy during exercise are sitting still.
That is also why chess can feel draining. After a long game you may be exhausted, hungry and unable to concentrate, but that tiredness is mental. It is real, it just doesn’t show up as a big number on a calorie counter.
Why top players train physically anyway
Many elite players run, swim, play other sports or lift weights. The goal is not to burn off calories from chess; it is stamina. Classical games can last six hours, top tournaments run for two weeks, and being fit helps with sleep, mood and concentration in the fifth hour of a game. See is chess a sport? for the wider debate, and chess boxing for the version of chess that really does burn calories.
FAQ
How many calories do chess players burn?
About 1.5 times what they burn sitting still. The Compendium of Physical Activities lists chess at 1.5 METs, which for a 70 kg (154 lb) person is about 105 kcal an hour, or about 35 kcal more than sitting quietly. A lab study measured about 138 kcal for a game lasting around 90 minutes.
Do chess grandmasters burn 6,000 calories a day?
No. The figure has no measurement behind it. It traces to an extrapolation from breathing-rate data on 11 amateur players in the 1970s; researchers who have checked the claim found no study that measured anything like 6,000 calories.
Does chess burn calories?
Yes, but only a little more than resting. Any waking activity burns calories; chess burns slightly more than sitting quietly because of stress and concentration, not because it is physically demanding.
How many calories does a chess game burn?
It depends on your body weight and how long the game lasts. Using the Compendium value, a 70 kg player burns about 525 kcal in a five-hour classical game, of which only about 175 kcal is extra compared with sitting still. Use the calculator on this page for your own numbers.
Why do chess players lose weight during tournaments?
Reports of players losing weight during long events are real, but the likely causes are stress, poor appetite, irregular meals and sleep, not the chess itself burning huge amounts of energy.
Is chess a good way to lose weight?
No. It burns barely more than sitting still. Chess is great for many things, but if you want to burn calories, any physical activity, even a slow walk, will do far more.
Does thinking hard burn calories?
A little. The brain uses energy all the time, and hard mental work raises your heart rate and stress hormones, but studies of chess players find only a small increase in total energy use.
Why do top players train physically?
Long tournaments are tiring, and fitness helps with stamina, sleep and concentration late in long games. Training for chess is about staying sharp, not about burning calories at the board.
Sources and how we checked
- 2024 Adult Compendium of Physical Activities: Miscellaneous (chess 1.5, cards 1.5, board games 1.3), Inactivity (sitting quietly 1.0), Walking and Sports. MET definition from Ainsworth et al., 2011.
- N. Troubat et al., “The stress of chess players as a model to study the effects of psychological stimuli on physiological responses”, European Journal of Applied Physiology 105 (2009).
- C. Rodoplu, R. Arabacı & R. Görgülü, “The comparison of heart rate variability and energy expenditure of chess players between chess game and physical activity”, Baltic Journal of Sport and Health Sciences.
- A. Strandberg, “Chess grandmasters do not burn 6000 calories per day” (2025); A. Gelman, Statistical Modeling blog (30 June 2025); ESPN (2019).
- All calorie figures on this page are computed as METs × kg × hours and were checked in code before publishing; the calculator uses the same formula.