BMR Calculator
Estimate your Basal Metabolic Rate — the calories your body burns at complete rest — using the Mifflin-St Jeor equation.
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Your results
Suggested macros at 2,556 kcal
| Macro | Grams | % of calories |
|---|---|---|
| Protein | 192 g | 30% |
| Carbohydrate | 256 g | 40% |
| Fat | 85 g | 30% |
What is BMR?
Basal Metabolic Rate (BMR) is the energy your body uses just to stay alive at complete rest — keeping your heart beating, your lungs breathing, and your cells repairing themselves. It does not include digesting food or any movement at all, which is why it's always lower than the number of calories you actually need in a day.
To get a daily calorie need, BMR is multiplied by an activity factor — see the TDEE calculator for that step, and the methodology page for the exact equation and its source.
The Mifflin-St Jeor equation
Published by Mifflin et al. in 1990, the equation is:
| Male | 10 × weight(kg) + 6.25 × height(cm) − 5 × age(yr) + 5 |
|---|---|
| Female | 10 × weight(kg) + 6.25 × height(cm) − 5 × age(yr) − 161 |
Worked example
A 30-year-old male weighing 70 kg and 175 cm tall:
| 10 × 70 + 6.25 × 175 − 5 × 30 + 5 | 1649 kcal/day |
|---|
This is a real output of the formula above for these inputs — enter your own numbers into the calculator above for your figure.
Common questions
- What is BMR?
- Basal Metabolic Rate is the number of calories your body needs to maintain basic life functions — breathing, circulation, cell repair — while completely at rest. It does not include digestion or any physical activity.
- What formula does this calculator use?
- The Mifflin-St Jeor equation: 10 × weight (kg) + 6.25 × height (cm) − 5 × age (years), plus 5 for males or minus 161 for females. It is generally regarded as more accurate for modern populations than the older Harris-Benedict equation.
- Is BMR the same as the calories I should eat?
- No. BMR is your body's baseline at complete rest. The calories you actually need in a day — your TDEE — also accounts for activity, and is what a calorie target should be based on. See the TDEE calculator for that number.
- Why does the calculator ask for sex?
- The Mifflin-St Jeor equation is published with two different constants, one for each sex, reflecting average differences in body composition. Selecting “prefer not to say” uses the midpoint of the two rather than either published form.
Track against your target
Calories Journal uses this same equation to set your daily target automatically from your profile, then tracks what you actually log against it. Start tracking free, or browse calories in common foods first.