Calculate Your BMR & Daily Calories
Use this Mifflin-St Jeor calculator to estimate your basal metabolic rate (BMR), maintenance calories (TDEE), and goal calories.
What Is the Mifflin-St Jeor Equation?
The Mifflin-St Jeor equation is one of the most widely used formulas for estimating your basal metabolic rate (BMR). BMR is the number of calories your body needs each day to support basic life functions like breathing, blood circulation, and cell repair.
Once you know BMR, you can estimate your total daily energy expenditure (TDEE) by multiplying BMR by an activity factor. TDEE is your approximate maintenance calorie intake.
Mifflin-St Jeor Formula
For men
BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age in years) + 5
For women
BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age in years) − 161
How to Use This Calculator
- Select your sex and age.
- Choose metric or imperial units.
- Enter your body weight and height.
- Pick your activity level as honestly as possible.
- Choose a calorie goal (maintain, cut, or gain).
After clicking Calculate, you will see:
- BMR (baseline calories at rest)
- TDEE (estimated maintenance calories)
- Goal calories (adjusted by your selected target)
Activity Multipliers Explained
Your activity multiplier has a big effect on calorie needs:
- 1.2: Sedentary (desk job, minimal movement)
- 1.375: Lightly active (light workouts a few days/week)
- 1.55: Moderately active (regular training)
- 1.725: Very active (hard training most days)
- 1.9: Extra active (labor + intense training)
If your results don’t match real-world progress after 2–3 weeks, adjust by 100–200 calories and monitor trends.
Why People Use the Mifflin-St Jeor Calculator
- To build a fat loss calorie target
- To plan muscle gain with controlled surplus
- To avoid random dieting and under-eating
- To set macro goals from a realistic calorie base
Practical Tips for Better Results
1) Track consistently
Use the same scale, same timing, and similar hydration conditions when checking weight. Day-to-day fluctuations are normal; weekly averages matter more.
2) Prioritize protein
A protein intake around 1.6–2.2 g/kg body weight can support satiety, training performance, and muscle retention while dieting.
3) Adjust based on data
Equations provide estimates, not perfect numbers. Your true maintenance is revealed by repeated tracking over time.
Frequently Asked Questions
Is Mifflin-St Jeor accurate?
It is generally considered one of the better population-level equations for estimating resting energy expenditure, but individual variation is still significant.
BMR vs TDEE: what’s the difference?
BMR is calories burned at complete rest. TDEE includes movement, training, and digestion. TDEE is what you usually use for meal planning.
Should I recalculate often?
Yes. Recalculate when body weight changes significantly (for example, every 5-10 lb or every 2-4 kg), or when your activity pattern changes.
Bottom Line
The Mifflin-St Jeor calculator gives you a strong starting point for calorie planning. Use it, track your outcomes, and refine your intake based on weekly progress. Consistency beats precision.
Note: This tool is educational and not a substitute for medical advice. If you have a medical condition, consult a qualified healthcare professional.