🔥 BMR Calculator
Estimate how many calories your body burns at rest using the three most widely used BMR equations.
Quick answer: Mifflin–St Jeor BMR for men = 10 × kg + 6.25 × cm − 5 × age + 5. A 30-year-old man who is 175 cm tall and weighs 70 kg has a BMR of about 1,649 kcal per day.
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BMR Calculator inputs
Result
Your BMR (Mifflin–St Jeor)
1,649 kcal
Calories your body burns per day at complete rest
| Mifflin–St Jeor | 1,649 kcal/day |
| Harris–Benedict (revised) | 1,696 kcal/day |
| Katch–McArdle | add body fat % |
Daily calories by activity level
| Activity level | Multiplier | Calories / day |
|---|---|---|
| Sedentary (little or no exercise) | × 1.2 | 1,979 kcal |
| Light (exercise 1–3 days/week) | × 1.375 | 2,267 kcal |
| Moderate (exercise 3–5 days/week) | × 1.55 | 2,556 kcal |
| Active (exercise 6–7 days/week) | × 1.725 | 2,845 kcal |
| Very active (hard exercise or physical job) | × 1.9 | 3,133 kcal |
How BMR is calculated
No equation measures metabolism directly – they predict it from body size, age and sex. This calculator shows three established formulas side by side so you can see the likely range.
Mifflin–St Jeor: 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5 (men) or − 161 (women)
Harris–Benedict (revised): men 88.362 + 13.397W + 4.799H − 5.677A · women 447.593 + 9.247W + 3.098H − 4.330A
Katch–McArdle: 370 + 21.6 × lean body mass(kg)
Worked example
A 30-year-old man, 175 cm and 70 kg: 700 + 1,093.75 − 150 + 5 = 1,649 kcal/day with Mifflin–St Jeor. The revised Harris–Benedict equation gives 1,696 kcal/day. If he has 15% body fat, his lean mass is 59.5 kg and Katch–McArdle gives 1,655 kcal/day.
From BMR to daily calories
Multiply BMR by an activity factor to estimate total daily energy expenditure:
- 1.2 – sedentary, desk job with little exercise
- 1.375 – light exercise 1–3 days a week
- 1.55 – moderate exercise 3–5 days a week
- 1.725 – hard exercise 6–7 days a week
- 1.9 – very hard training or a physical job
Tips for using your BMR
- Treat the result as a starting estimate: individual metabolism can differ by 10% or more.
- Don't eat below your BMR for long periods without supervision – it makes it harder to get enough protein and nutrients.
- Recalculate after every 4–5 kg of weight change, since BMR falls as you get lighter.
- Use Katch–McArdle only if your body-fat figure comes from a reliable method such as DEXA or a careful tape measurement.
For general information only – not medical advice. Consult a healthcare professional.
Frequently asked questions
What is BMR?
Basal metabolic rate is the energy your body uses to keep you alive at complete rest – breathing, circulation, temperature control and cell repair. It typically makes up 60–70% of the calories you burn each day.
Which BMR formula is most accurate?
For most adults Mifflin–St Jeor is the most accurate predictive equation and is recommended by dietetic associations. Katch–McArdle can be better for lean, muscular people when body fat is measured accurately.
How is BMR different from TDEE?
BMR is calories at rest. Total daily energy expenditure (TDEE) adds movement, exercise and digestion – it is BMR multiplied by an activity factor between 1.2 and 1.9.
Can I raise my BMR?
Building muscle through resistance training raises BMR modestly, because lean tissue burns more energy than fat. Very low-calorie diets can lower it, so avoid extreme deficits.