Calculate Your BMR
Use this calculator to estimate how many calories your body burns at rest in 24 hours.
What Is Basal Metabolic Rate (BMR)?
Basal metabolic rate (BMR) is the number of calories your body needs each day to keep you alive at complete rest. Think breathing, blood circulation, temperature regulation, hormone activity, and cell repair. It does not include exercise, walking, digestion, or other daily movement.
If you have ever asked, “How many calories do I burn doing nothing?” BMR is your answer. It is one of the most useful starting points for calorie planning, fat loss goals, and muscle gain strategies.
How This BMR Calculator Works
This page estimates BMR using two widely used evidence-based equations:
- Mifflin-St Jeor equation (often preferred for modern populations)
- Revised Harris-Benedict equation (classic and still commonly used)
Mifflin-St Jeor
- Male: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5
- Female: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161
Revised Harris-Benedict
- Male: BMR = 88.362 + (13.397 × weight(kg)) + (4.799 × height(cm)) − (5.677 × age)
- Female: BMR = 447.593 + (9.247 × weight(kg)) + (3.098 × height(cm)) − (4.330 × age)
BMR vs RMR vs TDEE
BMR
Strict resting calorie needs under highly controlled conditions.
RMR (Resting Metabolic Rate)
Similar to BMR but measured under less strict conditions. In practice, many people use BMR and RMR almost interchangeably for planning.
TDEE (Total Daily Energy Expenditure)
Your full daily calorie burn: BMR + movement + exercise + digestion. This calculator also gives a TDEE estimate by multiplying BMR with an activity factor.
How to Use Your Result
- Maintenance: Eat around your estimated TDEE to maintain weight.
- Fat loss: Start with a 10–20% calorie deficit below TDEE.
- Muscle gain: Start with a 5–15% calorie surplus above TDEE.
Recalculate every few weeks as your weight, activity, and goals change.
What Influences BMR?
1) Body Composition
Muscle tissue burns more calories at rest than fat tissue. More lean mass generally means higher BMR.
2) Age
BMR tends to decrease over time, partly due to changes in lean mass and hormone patterns.
3) Sex
On average, males often have higher BMR due to higher lean body mass.
4) Genetics and Hormones
Thyroid activity, stress hormones, and inherited differences can all affect resting energy use.
5) Energy Intake and Dieting History
Prolonged aggressive dieting can temporarily reduce energy expenditure, sometimes called adaptive thermogenesis.
Practical Tips for Better Results
- Prioritize resistance training to preserve or build lean mass.
- Aim for adequate protein intake across meals.
- Sleep 7–9 hours when possible.
- Use step counts or activity tracking for more accurate TDEE adjustments.
- Track trends weekly, not daily fluctuations.
FAQ
Is this calculator 100% accurate?
No equation is perfect for every person. Use this as a strong starting estimate, then adjust based on real progress over 2–4 weeks.
Should I choose Mifflin or Harris-Benedict?
Mifflin-St Jeor is generally preferred for many adults today. Harris-Benedict is still useful for comparison.
Can I use this for weight loss planning?
Yes. Estimate your TDEE, create a moderate deficit, and monitor body weight, waist measurements, and energy levels.
Final Note
BMR is a foundational number, not a verdict. Use it to guide decisions, then personalize with real-world data. For medical conditions, pregnancy, or eating disorder history, consult a qualified healthcare professional before major dietary changes.