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Holistic Health

BMR Calculator

Calculate your Basal Metabolic Rate (the calories your body burns at complete rest) and your Total Daily Energy Expenditure based on your activity level. Uses the Mifflin-St Jeor equation, the most accurate formula available.

BMR~1,700 calcalories at complete restTDEE~2,600 cal+ daily activity

TDEE builds directly on top of BMR. The gold extension is the energy added by movement.

Disclaimer

This calculator provides general wellness information only. Results are not medical advice and should not replace consultation with a qualified healthcare professional. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.

4 min read·Holistic Health

What is Basal Metabolic Rate?

Basal Metabolic Rate is the number of calories your body burns at complete rest simply to keep you alive. Even if you spent an entire day lying still, your body would still spend energy on breathing, circulating blood, producing new cells, repairing tissue, and holding a steady internal temperature. BMR measures that quiet, constant cost of being a living organism.

For most people who are not highly active, BMR makes up roughly 60 to 70 percent of all the calories they burn in a day. It is the single largest piece of the energy budget, which is why it is the foundation that every calorie target is built on top of. The number is driven mainly by body mass, height, age, and sex, with larger and younger bodies generally burning more at rest.

Be clear about what this figure is. A BMR calculator gives a statistical estimate drawn from population averages, not a personal measurement. Real basal metabolism varies with muscle mass, hormones, genetics, and how long someone has been dieting. Treat the result as a well-grounded starting point to test against your own results over a few weeks, not as a fixed biological constant.

How the calculation works

This calculator uses the Mifflin-St Jeor equation, the formula most dietitians consider the most reliable for the general population. It works in four steps.

  1. Convert weight to kilograms and height to centimetres if imperial units were entered.
  2. For men, calculate (10 x weight in kg) + (6.25 x height in cm) - (5 x age) + 5.
  3. For women, use the same structure but end with - 161 instead of + 5.
  4. Multiply the BMR by an activity factor (1.2 for sedentary up to 1.9 for very active) to get your TDEE.

Worked example: 30-year-old man, 70 kg, 175 cm, sedentary

  • 10 x 70 = 700
  • 6.25 x 175 = 1,093.75
  • 5 x 30 = 150
  • BMR = 700 + 1,093.75 - 150 + 5 = 1,649 calories per day
  • TDEE = 1,649 x 1.2 = 1,979 calories per day

Frequently asked questions

What is the difference between BMR and TDEE?

BMR is the energy your body uses at complete rest. TDEE, Total Daily Energy Expenditure, is BMR multiplied by an activity factor that accounts for movement, exercise, and the work of digesting food. BMR is the theoretical floor; TDEE is the practical number you actually plan meals around. Almost nobody lives at their BMR, so use TDEE as your maintenance target and adjust it up or down for muscle gain or fat loss.

Does muscle mass increase BMR?

Yes, though more modestly than gym folklore suggests. Muscle tissue is metabolically more active at rest than fat tissue, so a more muscular body does carry a higher resting burn. The effect is real but measured in tens of calories per kilogram of muscle, not hundreds. The Mifflin-St Jeor equation uses total body weight rather than composition, so two people at the same weight will get the same estimate even if one carries more muscle. That is one of the formula limitations worth keeping in mind.

Does BMR decrease with age?

Generally yes. The equation subtracts five calories for every year of age, reflecting the gradual decline in resting metabolism as people get older. Much of that decline is linked to the loss of muscle mass that tends to accompany ageing rather than age itself, which means consistent resistance training and adequate protein can slow it considerably. Recalculating every few years, or whenever your weight changes meaningfully, keeps the estimate honest.

BMR is one input into a fuller picture of your energy needs. The TDEE Calculator applies activity factors in more detail to find your true maintenance calories. The BMI Calculator offers a quick screening of weight relative to height, and once you know your calorie target the Macronutrient Calculator splits those calories into protein, carbohydrate, and fat.

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BMR vs TDEE: Which Number Should You Use?

BMR is a theoretical baseline, the calories your body would need if you were completely sedentary. Almost nobody actually lives at their BMR. The number that matters for practical nutrition is your TDEE: BMR multiplied by your activity factor.

Use your TDEE as your maintenance calorie target. Eat consistently below it to lose weight, consistently above it (with resistance training) to build muscle. Recalculate every 4 to 6 weeks as your weight changes, since BMR decreases as body weight decreases.