Medical Review: This article was written and reviewed in accordance with clinical nutrition guidelines (2026). Evidence-based content.
The Mifflin-St Jeor equation for women is the highly regarded formula for estimating basal metabolic rate (BMR) in healthy adult women. BMR is the number of calories your body burns at complete rest just to keep you alive: breathing, pumping blood, repairing cells, and running your brain. Knowing your BMR is the first step toward finding your maintenance calories and setting targets for weight loss or gain.
The women's formula explained
The Mifflin-St Jeor equation for women is:
BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161
That is it — four numbers and one subtraction. The formula uses kilograms for weight, centimeters for height, and years for age. If you use imperial units, convert first: 1 kg = 2.205 lb, 1 cm = 0.394 in. Our BMR handles both systems automatically.
What each part of the formula means
- 10 × weight(kg): every kilogram of body mass contributes about 10 calories per day to your resting burn. This is the largest driver of BMR.
- 6.25 × height(cm): taller bodies have more tissue to maintain, so height adds to resting calorie needs.
- − 5 × age: metabolism slows slightly with each year of life. After puberty, BMR drops about 5 calories per year.
- − 161: this constant adjusts for average differences in body composition between women and men. Men add 5 instead.
How the women's formula compares to men's
The men's formula is almost identical:
BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5
The only difference is the final constant: women subtract 161, men add 5. This gap of 166 calories reflects the average difference in lean body mass. Women typically have more body fat and less muscle than men of the same height and weight, and muscle is metabolically active tissue. That is why men's BMRs tend to run 100–400 calories higher than women's for similar body sizes.
Example calculation for women
Let's calculate BMR for a 28-year-old woman, 165 cm, 65 kg:
Step 1: BMR = 10 × 65 + 6.25 × 165 - 5 × 28 - 161 BMR = 650 + 1,031.25 - 140 - 161 = 1,380.25
Rounded to the nearest calorie, her BMR is 1,380 kcal/day. With moderate activity (1.55), her TDEE is 1,380 × 1.55 = 2,139 kcal/day.
Using the women's formula for TDEE
BMR is only the first step. To find your full daily calorie needs, multiply by an activity factor:
| Activity level | Multiplier | TDEE example for 1,380 BMR |
|---|---|---|
| Sedentary | 1.2 | 1,656 |
| Lightly active | 1.375 | 1,898 |
| Moderately active | 1.55 | 2,139 |
| Very active | 1.725 | 2,381 |
| Extra active | 1.9 | 2,622 |
Use the TDEE calculator to compute this automatically.
How activity level changes women's TDEE
Women often underestimate the impact of NEAT (Non-Exercise Activity Thermogenesis). A nurse who walks 12,000 steps per day burns significantly more calories than a desk worker who drives everywhere, even if both attend the same number of gym sessions. When choosing an activity level, include your walking, standing, and daily movement — not just your workouts.
Common questions
- Do I need a separate formula if I am on birth control? Some hormonal contraceptives can slightly affect water retention and appetite, but they do not meaningfully change your BMR. Use the standard formula and track your weight to verify.
- Does the formula work during my menstrual cycle? BMR is relatively stable across the menstrual cycle, though resting energy expenditure can fluctuate by 50–150 calories depending on the phase. This variation is normal and averages out over time.
- Can I use this formula if I am very muscular? Yes, but very muscular women may have a higher BMR than the formula predicts because muscle is metabolically active. Consider the Katch-McArdle equation if you know your body fat percentage.
Practical next steps
- Calculate your BMR with the BMR.
- Estimate your TDEE by multiplying by your activity factor.
- For weight loss, subtract 300–500 calories. For gain, add 250–500. For maintenance, eat at TDEE.
- Track your weight for 2–3 weeks and adjust based on real results.
- Use the Calorie Calculator to ensure adequate protein.
Sources and further reading
These independent, authoritative sources inform the methods used on this page.
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Open Calorie CalculatorMedical & Scientific References
- World Health Organization (WHO) - Healthy Diet
- Mayo Clinic - Counting Calories
- National Institutes of Health (NIH) - Weight Management
Expert FAQs & Psychological Impact
Let's be incredibly honest for a moment: dealing with this can cause serious compliance fatigue and anxiety. You are not alone. Here are the most critical, edge-case questions answered with complete transparency to protect your well-being and ensure you have all the facts.
1. How do I manage the anxiety around getting this exactly right?
The psychological burden of trying to be perfect can lead to decision paralysis. Experts recommend focusing on the 80/20 rule. Whether it's nutrition or sizing, consistency and general accuracy will yield 90% of your desired results. Do not let minor fluctuations disrupt your peace of mind.
2. What are the long-term effects of ignoring these guidelines?
Over time, systemic neglect cascades into larger physical and mental health issues. Proper adherence mitigates chronic discomfort and sets a baseline for sustainable lifestyle improvements. The goal is to build a foundation that supports you passively.
3. How often should I re-evaluate my baseline numbers?
Your body and circumstances are not static. It is highly recommended to reassess your measurements and caloric needs every 3 to 6 months, or immediately following any significant lifestyle or weight change. Proactive adjustments prevent reactive stress.
4. Is there a danger in relying entirely on automated calculators?
While calculators provide a mathematically sound starting point, they cannot account for nuanced human biology. Stress, sleep, and hormonal variations play a massive role. Always use calculator outputs as a guide, not gospel, and adjust based on real-world feedback from your own body.