Disclaimer: The results given by this BMR calculation tool should be used only as a guide and should not replace medical advice. Please bear in mind that, when interpreting the results of this BMR calculator, other factors such as your lean body mass should be considered. You should always speak to a qualified Doctor or health professional for advice and guidance before making any dramatic changes to your lifestyle.
How to calculate your BMR
To calculate your BMR you enter your height and weight measurements, as well as your age and biological sex, into the BMR formula. The calculation returns a figure known as your Basal Metabolic Rate (BMR), which represents the number of calories you might burn in a day if you undertook little or no activity.
There are a number of different BMR equations in use today, from the more modern Mifflin - St Jeor formula, which was established in 1990, to the older Harris-Benedict formula from 1919 and the revised Harris-Benedict formula from 1984. You'll find different BMR calculators reference different formulae, so we've ensured you have access to all three in our calculator. It has been suggested that there is about a 5% difference between figures returned by the Mifflin - St Jeor formula and Harris-Benedict formula, with the former being the more accurate.3
When calculating your BMR, it is important to note that men and women have different formulae, due to the fact that men tend to have a higher percentage of lean body weight than women.
For the BMR calculations below, we're referencing the more modern Mifflin - St Jeor formula. You can calculate your BMR by using one of the these:
BMR formula for men
- BMR (metric) = (10 × weight in kg) + (6.25 × height in cm) - (5 × age in years) + 5
- BMR (imperial) = (4.536 × weight in pounds) + (15.88 × height in inches) - (5 × age) + 5
Mifflin - St Jeor (1990) 1
BMR formula for women
- BMR (metric) = (10 × weight in kg) + (6.25 × height in cm) - (5 × age in years) - 161
- BMR (imperial) = (4.536 × weight in pounds) + (15.88 × height in inches) - (5 × age) - 161
Mifflin - St Jeor (1990) 1
The Harris-Benedict formula
The Harris-Benedict equation was the earliest BMR formula created and referenced, following its publication in 1919. As a reminder, the Harris-Benedict formula was revised in 1984, using new data in order to improve its accuracy. If you're wondering which one you want to use and reference in your calculations, it's worth reading our article about the BMR formulae here.
- Mifflin, MD; St Jeor, ST; Hill, LA; Scott, BJ; Daugherty, SA; Koh, YO (1990). "A new predictive equation for resting energy expenditure in healthy individuals". The American journal of clinical nutrition 51 (2): 241-7.
- A M Roza, H M Shizgal, "The Harris Benedict equation reevaluated: resting energy requirements and the body cell mass", The American Journal of Clinical Nutrition, Volume 40, Issue 1, July 1984, Pages 168–182.
- "Which formula are recommended by nutritionists and scientists to measure Basal Metabolic Rate?" - ResearchGate.
Calculating daily calorie requirement
Once you've worked out your BMR, you can calculate your daily calorie requirement by multiplying your BMR by one of the following activity level factors:
- If you are sedentary (little or no exercise)
Calories Per Day = BMR x 1.2
- If you are lightly active (light exercise or sports 1-3 days/week)
Calories Per Day = BMR x 1.375
- If you are moderately active (moderate exercise 3-5 days/week)
Calories Per Day = BMR x 1.55
- If you are very active (hard exercise 6-7 days/week)
Calories Per Day = BMR x 1.725
- If you are super active (very hard exercise and a physical job)
Calories Per Day = BMR x 1.9
What exactly is BMR?
BMR stands for Basal Metabolic Rate and represents the number of calories you would burn in a day if you were inactive and stayed in bed all day. Our BMR calculator allows you to calculate not only the number of calories you burn when inactive, but also a daily calorie figure that takes into account your lifestyle activity level. These two figures together give you a representative figure for your daily calorie intake. You can learn more about BMR in our article, how to calculate BMR.
It is important to bear in mind that Basal Metabolic Rate calculations do not take into account for lean body mass, which will obviously have a factor of its own. Very muscular people, for example, will receive a figure that probably under-estimates their calorie needs and very overweight people will likely get a calculation that over-estimates their calorie requirements.
Other health calculators available on this website include the popular pregnancy calculator.
If you have any problems using this calculator tool, please contact me.