Turning a stair climb into watts
Comparing stair climbs by flights and time alone breaks down as soon as two people weigh different amounts, because the work of lifting a body against gravity is not the same. This calculator takes body weight, flights climbed, height per flight and the time taken, then reports the total vertical rise and the average vertical power produced over that climb in watts, along with power per pound, average vertical speed and total vertical work.
The formulas are the plain physics ones. Vertical work is body weight times a gravitational acceleration of 9.80665 times the total rise, and power is that work divided by the elapsed time. Height per flight is not hard-coded, because it varies from building to building; the starting value of 10 ft is only an example. Remember that climbing from floor 1 to floor 10 means 9 flights.
The kcal line converts the calculated vertical work into calorie units and is not the energy your body spent. Human mechanical efficiency is well under 100%, and horizontal travel, arm movement and resting metabolism are not included. Descending is excluded as well, since gravity does the work on the way down and the same formula does not apply. Flat-out stair sprints load the cardiovascular system heavily, so check with a clinician first if you have a condition.
FAQ
The kcal here is the vertical work of lifting your body weight converted straight into calorie units. Human mechanical efficiency is far below 100%, so actual metabolic cost is several times larger.
Multiply the height of one step by the number of steps in a flight. It differs between buildings, so measuring once beats keeping the 10 ft starting value.
No. This calculation covers only the vertical work of climbing. On the way down gravity does the work, so it cannot be added with the same formula. Enter the climbing time only.