calculator O2 CONSUMPTION TREADMILL WALK
What is the relative oxygen consumption of walking 3 mph at a 3% treadmill grade?
In the expression below we are adding a resting component, horizontal component and a vertical component of oxygen consumption:

In this formula you can replace '3.0' (both mph)
and .03 (percent grade) with your numbers.
Resting component = +3.5 ml O2/kg/min
Horizontal component = Speed (meters/min) X .1 ml (O2/kg/min)/(m/min)
Vertical component = Grade X speed m/min X 1.8 ml O2/kg/min
1 mph = 26.8224 meters/minute.
Horizontal component oxygen consumption = .1 ml (O2/kg/min)/(m/min)
Vertical component oxygen consumption = 1.8 ml O2/kg/min/(m/min)

3.5 + (3.0 *26.8224)*.1 +.03 * (3.0 *26.8224) * 1.8 = 15.89
EXAMPLE answer in the equation should read 15.89 (ml O2/kg/min)

calculator KCAL PER MINUTE TREADMILL WALK
How many kcal/minute burned during walking on treadmill?
In the expression below we are adding a resting component, horizontal component and a vertical component of oxygen consumption and converting to kcal/minute (about 5 kcal per Liter O2 consumed for total body weight -- 200 lb in this example):

In this formula you can replace '3.0' (both horizontal and vertical mph)
and .03 (percent grade) and 200 (body weight in lbs) with your numbers.
Resting component = +3.5 ml O2/kg/min
Horizontal component = Speed (meters/min) X .1 ml (O2/kg/min)/(m/min)
Vertical component = Grade X speed m/min X 1.8 ml O2/kg/min
1 mph = 26.8224 meters/minute.
Horizontal component oxygen consumption = .1 ml (O2/kg/min)/(m/min)
Vertical component oxygen consumption = 1.8 ml O2/kg/min/(m/min)
Conversion to kcal/per min (200 lbs/2.204623 lbs/kg) * 5 kcal/L* .001 L/ml

(3.5 + (3.0 *26.8224)*.1 +.03 * (3.0 *26.8224) * 1.8) * (200/2.204623)*5*.001 =7.2
EXAMPLE answer in the equation should read 7.2 kcal