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How many calories do you burn at rest? Your BMR explained
Written byJodi M Johnson
Reviewed byHeeral Patel
Meet BMR: the unsung hero of your metabolism. Your body’s always working – even at rest – so knowing how to calculate your basal metabolic rate could be a game-changer for your health goals
Summary
1What’s BMR?
Basically, it’s the number of calories your body needs just to keep you alive while you’re resting. Even when…
2BMR and weight loss
If you’re trying to lose weight, understanding your BMR can be a real guiding light. But while your BMR forms the…
3How to calculate your BMR
You’ve probably seen those guidelines that say, “An adult needs X calories a day”? That’s just an average, it’s…
Ever wondered how your body keeps going even when you’re just chilling on the sofa? Well, it’s all thanks to something called your BMR (Basal Metabolic Rate). Sounds fancy, right? But it’s actually pretty simple and super useful to know.
Your body is like a busy little engine running 24/7. Even when you’re resting, it’s working hard behind the scenes, like helping you to breathe, keeping your heart pumping, digesting food, repairing cells and keeping your temperature just right. All these essential tasks need energy and that’s exactly what your BMR measures – the number of calories your body burns just to keep you alive and ticking.1
Why does this matter? Knowing your BMR helps you understand how many calories your body needs at rest. This can be influential when setting calorie goals for weight loss, maintenance or just improving your overall health awareness. It’s like having a personalised fuel guide for your body.1
What’s BMR?
Basically, it’s the number of calories your body needs just to keep you alive while you’re resting. Even when you’re doing nothing, your body is still burning calories to keep everything running smoothly. That’s what your BMR measures, the calories needed for these basic, life-sustaining functions.1
Here’s the cool part – your BMR isn’t the same as everyone else’s. It depends on your unique traits like your height, weight, age, gender, genetics and even your body composition. For example, muscle burns more calories at rest than fat does. So, if you have more muscle, your BMR will be higher than someone with less.1,2
Wondering what makes a good basal metabolic rate? Knowing your BMR is super helpful for managing your weight, planning your nutrition and just staying on top of your health, allowing you to set realistic goals and make smarter choices.
Why’s BMR important?
Energy needs
BMR represents the largest component of your total daily energy expenditure. Understanding your BMR helps in estimating how many calories your body needs to function at rest, providing a baseline for determining your overall energy requirements.3,4
Weight loss or gain
Understanding your BMR helps you create a calorie deficit (consuming fewer calories than your body needs). However, weight loss isn't just about cutting calories, it's about doing it in a way that preserves your lean muscle mass. Muscle tissue burns more calories at rest than fat tissue, so maintaining muscle is key to sustaining a healthy metabolism.5
If you're looking to gain weight, especially muscle, understanding BMR is equally important. Gaining muscle increases your BMR because muscle tissue requires more energy to maintain than fat tissue.5
BMR and weight loss: what’s the connection?
If you’re trying to lose weight, understanding your BMR can be a real guiding light. But while your BMR forms the foundation of your calorie needs, it's not the full picture. Many people assume that knowing their BMR is enough to figure out how many calories they should eat to lose weight, but that’s only part of the story. Your actual daily calorie burn – known as your Total Daily Energy Expenditure (TDEE) – also includes all the energy you use through movement, exercise, digestion and even fidgeting.6,7
Once you know how much energy your body needs at rest, you can begin to tailor your calorie intake based on your lifestyle and activity levels. This makes your health goals – whether it’s weight loss, maintenance or gain – more personalised and realistic.
Think of BMR as the base of the pyramid. It’s essential to know, but to get the full picture, you’ll also need to consider how active you are day to day.
That’s where TDEE comes in and why taking a holistic view of your body’s energy needs is the key to long-term success.
What affects your BMR?
As we age, our metabolism naturally slows down – mainly because we lose muscle mass (which burns a lot of energy) and gain more body fat, especially around the belly. This shift lowers our basal metabolic rate (BMR) and reduces the calories we burn, even at rest.8.9
With less muscle and less activity, our bodies need fewer calories. But if we keep eating the same amount, that extra energy gets stored as fat. Abdominal fat, in particular, can affect how the body processes sugar and fats, leading to issues like reduced glucose tolerance (meaning your blood sugar is higher than it should be).8.9
Healthy habits like staying active, eating balanced meals and not smoking can help maintain muscle, support metabolism and keep your body functioning well as you age.
A large study looking at over 8,000 white individuals aged seven to 74 found that sex has a clear impact on BMR, especially in children and teenagers. Boys had significantly higher BMRs than girls (on average burning 750 to 1,000 kilojoules more per day) even when differences in body size and fat-free mass (FFM) were taken into account. This suggests that it’s not just about having more muscle; other factors like hormones, muscle fibre types and cellular activity likely play a role.10
However, in adults, the picture changes. Once fat-free mass is accounted for, sex no longer predicts BMR. In other words, a man and a woman with the same amount of lean mass will have roughly the same resting metabolic rate. The study also showed that BMR tends to decline with age, but this is largely due to a loss of fat-free mass over time, rather than age itself being the direct cause.10
So, while sex matters a lot for metabolic rate in younger years, in adulthood it’s your muscle mass that really counts. Building and maintaining that lean mass is key to keeping your metabolism ticking over efficiently as you get older.10
Yes, muscle mass can make a difference to your BMR. Muscle needs more energy to maintain than fat, so generally, people with more muscle tend to have a slightly higher BMR.5
It’s not a massive contrast, but every bit helps when your body’s burning energy in the background.
A study on twins found that about 40% of the differences in BMR are down to genetics. Even things like how your body reacts to overfeeding or dieting, and whether you store or burn extra calories, can be influenced by your DNA.11
In short, your metabolism is partly inherited, which helps explain why some people naturally burn energy faster than others. But lifestyle still matters – your choices work alongside your genetics to shape your overall energy balance.11
Think of them as little messengers that help control how much energy your body uses. Thyroid hormones, for example, can either ramp things up or slow them down – too much can lead to a fast-burning metabolism, while too little can make things sluggish.12
How to calculate your BMR
You’ve probably seen those guidelines that say, “An adult needs X calories a day”? That’s just an average, it’s much more personalised than that – so let’s work yours out.
There are two main formulas used to calculate your BMR, the Harris-Benedict and the Mifflin-St Jeor equations. Don’t worry – they sound more complicated than they are.
The Harris-Benedict equation is one of the older methods. It takes into account your weight, height, age and sex to estimate how many calories your body burns at rest. It’s still widely used, but not quite as accurate as newer methods.
That brings us to the Mifflin-St Jeor equation, which is now considered more reliable for most people. Like Harris-Benedict, it uses your weight, height, age and sex, but the maths is slightly different and tends to give a result that better reflects modern lifestyles.
Both formulas give you a number – your BMR – which is a useful starting point for setting calorie targets. You don’t need to crunch the numbers yourself unless you want to; there are plenty of free BMR calculators online that do the maths for you.
Female BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age in years) - 161
Male BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age in years) + 5
An example: a 32-year-old female weighing 70kg at a height of 180cm
(10 x 70) + (6.25 x 180) – (5 x 32) – 161 = 1504 BMR
FAQs
On average, women burn about 1300 to 1500 calories a day just by keeping their bodies running at rest, while men burn around 1600 to 1800. But once you factor in things like movement, stress and daily activities, the total number of calories burned jumps. That means most women end up burning around 1950 to 2250 calories a day, and men around 2400 to 2700, but it will also depend on your activity levels.14
Some research suggests that having a higher-than-average BMR isn’t automatically better, in fact, it’s linked with higher all-cause mortality, especially when BMR exceeds about 36 kcal/m²/hour, compared to the sweet spot around 31–34 kcal/m²/hour.15
Putting it simply, the numbers (36 kcal/m²/hour, 31–34 kcal/m²/hour) are just a way to measure how much energy your body is burning based on your body size and time. This means your body is using more energy than usual when your resting energy burn goes above a certain level – about 36 calories per square metre of body size, per hour. The ideal range seems to be somewhere between 31 and 34 calories per square metre per hour.15
You can’t change your BMR drastically, but things like building muscle, staying active and getting enough sleep can give it a gentle nudge. It's more of a slow burn than a big jump or ‘boost’.
Think of BMR as just one part of your metabolism. Your metabolism is the whole system that turns food into energy and BMR is the energy your body uses just to keep you alive at rest – like breathing, circulating blood and keeping your organs ticking. So BMR is the quiet engine running in the background, while metabolism covers the full journey of energy use, from sleeping to sprinting.
BMR shouldn’t be used on its own for dieting. It’s more effective to use your BMR as a starting point, then adjust with activity level to calculate your TDEE and base any calorie deficit on that more complete picture. By doing so, you make dieting both realistic and sustainable rather than guessing off just your “resting” calorie figure.5
If you're looking to make the most of your BMR for your diet goals, it might be a good idea to schedule a call with a nutritionist who can walk you through how to use it effectively. For more personalised guidance, reaching out to a registered dietitian or nutritionist can really help you create a plan that fits your body and lifestyle.
The final say
And there you have it, your backstage pass to understanding BMR. Whether you're curious about how many calories you burn doing absolutely nothing or looking to use that number to help with your health goals, knowing your BMR is a great place to start. It's not magic, but it is a smart little tool in your wellness toolkit.
And hey, while you’re at it, why not have a play with our protein calculator to see just how much protein your body’s really craving?
This article provides informational advice and is not a substitute for medical care. Curated by experts for accuracy, we take great care to ensure the information is up-to-date and relevant. However, you should always consult your GP or healthcare professional before using supplements or alternative products, particularly if you have medical conditions or are under supervision.
1. Better Health. Metabolism [Internet]. Better Health Channel. 2012. Available from: https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/metabolism
2. McPherron AC, Guo T, Bond ND, Gavrilova O. Increasing muscle mass to improve metabolism. Adipocyte [Internet]. 2013 Apr;2(2):92–8. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3661116/
3. Molé PA. Impact of Energy Intake and Exercise on Resting Metabolic Rate. Sports Medicine [Internet]. 1990 Aug;10(2):72–87. Available from: https://link.springer.com/article/10.2165/00007256-199010020-00002
4. Cj H. Basal Metabolic Rate Studies in Humans: Measurement and Development of New Equations [Internet]. Public health nutrition. 2005. Available from: https://pubmed.ncbi.nlm.nih.gov/16277825/
5. Farhana A, Rehman A. Metabolic Consequences of Weight Reduction [Internet]. PubMed. Treasure Island (FL): StatPearls Publishing; 2023. Available from: https://www.ncbi.nlm.nih.gov/books/NBK572145/
6. TDEE Calculator [Internet]. Calculator.net. 2019. Available from: https://www.calculator.net/tdee-calculator.html
7. Ostendorf DM, Caldwell AE, Creasy SA, Pan Z, Lyden K, Bergouignan A, et al. Physical Activity Energy Expenditure and Total Daily Energy Expenditure in Successful Weight Loss Maintainers. Obesity [Internet]. 2019 Feb 25;27(3):496–504. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6392078/
8. H S, F K. [Aging, Basal Metabolic Rate, and Nutrition] [Internet]. Nihon Ronen Igakkai zasshi. Japanese journal of geriatrics. 1993. Available from: https://pubmed.ncbi.nlm.nih.gov/8361073/
9. Palmer AK, Jensen MD. Metabolic changes in aging humans: current evidence and therapeutic strategies. Journal of Clinical Investigation [Internet]. 2022 Aug 15;132(16). Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9374375/
10. Lazzer S, Bedogni G, Lafortuna CL, Marazzi N, Busti C, Galli R, et al. Relationship Between Basal Metabolic Rate, Gender, Age, and Body Composition in 8,780 White Obese Subjects. Obesity [Internet]. 2010 Jan;18(1):71–8. Available from: https://onlinelibrary.wiley.com/doi/full/10.1038/oby.2009.162
11. Bouchard C, Pérusse L, Dériaz O, Després J, Tremblay A. Genetic influences on energy expenditure in humans. Critical Reviews in Food Science and Nutrition. 1993 Jan 1;33(4-5):345–50.
12. Shahid MA, Sharma S, Ashraf MA. Physiology, Thyroid Hormone [Internet]. National Library of Medicine. StatPearls Publishing; 2023. Available from: https://www.ncbi.nlm.nih.gov/books/NBK500006/
13. Damjanovic SS, Stojic RV, Lalic NM, Jotic AZ, Macut DP, Ognjanovic SI, et al. Relationship between basal metabolic rate and cortisol secretion throughout pregnancy. Endocrine. 2009 Jan 20;35(2):262–8.
14. Popson MS, Dimri M, Borger J. Biochemistry, Heat and Calories [Internet]. PubMed. Treasure Island (FL): StatPearls Publishing; 2023. Available from: https://www.ncbi.nlm.nih.gov/books/NBK538294/
15. Ruggiero C, Metter EJ, Melenovsky V, Cherubini A, Najjar SS, Ble A, et al. High Basal Metabolic Rate Is a Risk Factor for Mortality: The Baltimore Longitudinal Study of Aging. The Journals of Gerontology Series A: Biological Sciences and Medical Sciences. 2008 Jul 1;63(7):698–706.
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