BMR Calculator
Calculate your Basal Metabolic Rate and daily calorie needs.
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Your Basal Metabolic Rate (BMR) is the energy your body uses at complete rest just to keep breathing, circulating blood and maintaining temperature. This calculator estimates it from your weight in kg, height in cm, age and gender, then multiplies it by four activity levels to show roughly how many calories you burn on a normal day.
The Mifflin-St Jeor equation used here
Men: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5 Women: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age − 161
The equation was published by Mifflin, St Jeor and colleagues in 1990. A 2005 evidence review for the American Dietetic Association found it the most accurate of the common prediction equations for healthy adults, which is why many dietitians and fitness apps now prefer it to the older Harris-Benedict formula.
Worked example: a 30-year-old woman, 60 kg, 160 cm
10 × 60 = 600, 6.25 × 160 = 1000 and 5 × 30 = 150, so BMR = 600 + 1000 − 150 − 161 = 1,289 kcal/day. The calculator then shows:
| Activity level | Multiplier | Calories/day |
|---|---|---|
| Sedentary | × 1.2 | 1,547 |
| Light exercise | × 1.375 | 1,772 |
| Moderate exercise | × 1.55 | 1,998 |
| Heavy exercise | × 1.725 | 2,224 |
For comparison, a 35-year-old man weighing 75 kg at 175 cm gets 750 + 1093.75 − 175 + 5 = 1,673.75, shown rounded as 1,674 kcal/day, and 2,009 kcal as a sedentary total.
Picking the right activity row
- Sedentary (1.2): desk job, commuting by car or metro, little planned exercise.
- Light (1.375): exercise or sport one to three days a week.
- Moderate (1.55): three to five days a week.
- Heavy (1.725): hard training six or seven days a week.
Most people overrate their activity. If you are unsure, start one row lower and adjust after two or three weeks of tracking your weight. The tool stops at 1.725, so manual labourers who also train daily may burn more than any row shows.
Using the number for weight goals
Your activity-adjusted figure approximates maintenance calories. Eating a few hundred calories below it leads to gradual weight loss, and a similar surplus supports muscle gain alongside strength training. BMR itself is not an eating target; it is what you would burn lying in bed all day. The calorie calculator builds a goal-based daily target, and the macro calculator splits it into protein, carbs and fat.
Limits of any BMR formula
The equation knows your size but not your body composition. A muscular person burns more at rest than predicted, and someone with a higher body-fat percentage often burns less. Thyroid conditions, some medicines, pregnancy and breastfeeding also change energy needs. Treat the result as an estimate to refine with real-world tracking, not as medical advice.