Daily Energy Intake and Expenditure

Want to estimate your daily energy needs and expenditure?

This calculator allows you to estimate your daily energy requirements based on your 'basal metabolism rate' (BMR) and the energy you use for activities each day. The BMR is the minimum amount of energy required to support your basic body functions such as keeping your vital organs working and your body at ~37^oC.

Both the BMR and the energy used for other activities depends on many factors such as your fitness level, height, weight and sex - the calculator below only provides a crude estimate of your individual needs. If you are looking for a more detailed analysis please consult a health professional.

This calculator is intended for educational purposes only for a course on chemical thermodynamics and no responsibility is taken for its accuracy.

Press the "calculate" button to work out your BMR and overall requirements and the "reset" button to clear your entries.

Resting and Other Activities

Energy Requirement ^*

1. Basal Metabolism Rate (BMR)

About you:

(a) sex

female male

(b) age

years

(d) approximate height

2. Activities

indicate the number of minutes (if any) spent on the activities below each day:

(a) studying/reading/watching TV

(b) aerobics

light:
medium:
intensive:

light:
medium:
intensive:

(d) walking

light:
medium:
intensive:

(e) cycling

light:
medium:
intensive:

(f) swimming

light:
medium:
intensive:

overall estimated energy requirement

0

The SI unit of energy is the joule (symbol 'J'), which is the energy expended moving an object one metre by a force of one newton. It is roughly the energy required to lift a 1 kg book by 10 cm at the surface of the earth. One kilojoule is equal to one thousand joules: 1 kJ = 1000 J.

A calorie (lower case 'c', symbol 'cal') was originally defined as the amount of heat required to heat one gram of water by one degree Celsius. It has since been redefined in terms of the joule: 1 cal = 4.184 J or 1 J = 0.2390 cal.

The Calorie (upper case 'C', symbol 'Cal') used in dietary labels is actually 1000 cal or 1 kcal:

1 Cal = 1000 cal = 1 kcal
1 Cal = 4.184 kJ

Thus, an apple provides roughly 125 Cal or 125 kcal or 523 kJ.