Endo-View · Simulations
My body in numbers
Your body has been working since the day you were born. Enter your age to see what it has already done: how many times your heart has beaten, how much blood it has moved, how many breaths you have taken, how many of your cells have been replaced and how long you have slept.
Since the day you were born
estimate- Days lived
- 11 thousandMonths: 360 · Weeks: 1.6 thousand · Hours: 260 thousand
- Heartbeats
- 1.3 billionLikely 1.1 billion to 1.6 billion
- Blood pumped, in litres
- 66 millionLikely 53 million to 79 millionOlympic swimming pools that blood would fill (2.5 million litres each): 26
- Breaths
- 290 millionLikely 230 million to 350 million
- Cells replaced
- 2.4 quadrillionLikely 1.9 quadrillion to 2.9 quadrillionMostly blood cells and the cells that line the gut.
- Time asleep, in years
- 12Likely 9.3 to 14
These are estimates for a typical person of your age, not measurements of you. Yours could be about a fifth higher or lower: a fitter heart beats more slowly, and a bigger body moves more blood.
Worked out on your device. Your age is not sent anywhere or kept.
Your body, by size
Add your height to see your skin area.
Estimates for a typical body of your age and size. Blood is about 7% of a body’s weight, and water about half of an adult’s and more of a child’s. Most of the cells are red blood cells.
Your card
How this is worked out
Your life is split into stretches, from newborn to adult. For each one we use what is typical for it: the resting heart rate, the breathing rate, how much blood one beat moves, and the size of the body. Then the stretches are added up, minute by minute, from the day you were born.
| Age | Heartbeats a minute | Breaths a minute | Blood per beat, in millilitres | Body mass, in kg | Sleep a day, in hours |
|---|---|---|---|---|---|
| 0 to 1 | 125 | 40 | 10 | 7 | 14 |
| 1 to 3 | 110 | 28 | 18 | 12 | 13 |
| 3 to 6 | 100 | 23 | 28 | 17 | 11.5 |
| 6 to 12 | 90 | 19 | 40 | 29 | 10 |
| 12 to 18 | 80 | 16 | 62 | 52 | 9 |
| 18 and over | 72 | 15 | 70 | 70 | 7.5 |
Cells replaced: an adult body replaces about 330 billion cells a day, mostly blood cells and the cells that line the gut. For a child that is scaled by body mass.
By size: blood is counted as millilitres for each kilogram of weight (65 to 75 for an adult, more for a child), water as a share of the weight (about 50 to 65% of an adult, more of a child), skin area with the Mosteller formula, and cells as about 30 trillion in a body of 70 kg, scaled by weight, with a wide range.
Time asleep: the hours of sleep a day that doctors recommend for each age, naps included, taken from the middle of the range. About a third of a life.
Heartbeats and breaths are counted at rest. A run, a fever or a fright makes the heart beat faster for a while, so the true number is somewhat higher. Days lived, and the same time in months, weeks and hours, are simple arithmetic and have no range.
Every figure here is an estimate, and the ranges show how much it could differ. It is for learning, not medical advice.
Where the values come from
- Resting heart rate and breathing rate by age: Fleming S. et al., “Normal ranges of heart rate and respiratory rate in children from birth to 18 years of age: a systematic review of observational studies”, The Lancet 377 (2011); and the American Heart Association’s Pediatric Advanced Life Support reference ranges.
- Blood moved by one beat: worked out from the typical cardiac output for a body of that size (about 5 litres a minute at rest for an adult), divided by the heart rate.
- Body mass by age: the medians of the WHO Child Growth Standards and the CDC growth charts.
- Cells replaced: Sender R. and Milo R., “The distribution of cellular turnover in the human body”, Nature Medicine 27 (2021).
- Sleep by age: Paruthi S. et al., “Recommended amount of sleep for pediatric populations”, Journal of Clinical Sleep Medicine 12 (2016); Watson N. et al., “Recommended amount of sleep for a healthy adult”, Sleep 38 (2015); both American Academy of Sleep Medicine consensus statements.
- Blood and water: Nadler S. et al., “Prediction of blood volume in normal human adults”, Surgery 51 (1962); and Hall J., Guyton and Hall Textbook of Medical Physiology.
- Skin area: Mosteller R., “Simplified calculation of body-surface area”, New England Journal of Medicine 317 (1987).
- Cells in the body: Sender R., Fuchs S. and Milo R., “Revised estimates for the number of human and bacteria cells in the body”, PLoS Biology 14 (2016).