BMR & TDEE Calculator (Mifflin–St Jeor)
Calculate your basal metabolic rate—the calories your body burns at rest—and estimate total daily energy expenditure based on activity level. The Mifflin–St Jeor equation is widely used for nutrition planning.
Results
Basal metabolic rate
1370 kcal/day
Total daily energy expenditure
2124 kcal/day
Activity factor ×1.550
Converted inputs
Weight 65.0 kg • Height 165.0 cm
How to Use This Calculator
Provide accurate measurements
Enter current height, weight, and age. Toggle units as needed—values are converted internally for the Mifflin–St Jeor formula.
Select activity level
The activity factor adjusts resting calories to estimate maintenance needs. Choose the option that best matches your weekly routine.
Apply BMR and TDEE
Use BMR for resting comparisons, and TDEE to set calorie targets. Create deficits or surpluses relative to TDEE for weight loss or gain.
Formula
Male BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5
Female BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161
TDEE = BMR × Activity Factor
- Mifflin–St Jeor is validated for a wide range of body sizes.
- Activity factors approximate the extra energy required for daily movement.
- For precise planning, reassess measurements after significant weight change.
Full Description
Basal metabolic rate reflects the calories required to sustain essential bodily functions at rest. The Mifflin–St Jeor equation is widely adopted in dietetics for its accuracy across diverse populations. Total daily energy expenditure multiplies BMR by an activity factor to estimate maintenance calories.
Use BMR/TDEE as a foundation for nutrition planning, then adjust for specific goals (weight loss, muscle gain, athletic performance). Pair these estimates with progress tracking and healthcare guidance for best results.
Frequently Asked Questions
Why use Mifflin–St Jeor instead of Harris-Benedict?
Research shows Mifflin–St Jeor provides better accuracy for modern populations. Harris-Benedict is still useful but often overestimates needs.
How often should I recalculate BMR?
Recalculate after notable weight changes (±5%), shifts in activity level, or every few months during a health program.
Is the activity factor precise?
Activity factors are approximations. If your lifestyle varies, average your typical week or adjust your calorie targets based on progress.
Can I use this calculator for medical conditions?
It provides general guidance. Individuals with medical conditions should consult dietitians or clinicians for personalized recommendations.