Me Formula Calculator: What It Is & How to Use

The “Me formula” calculator on this page works out your basal metabolic rate (BMR) — the number of calories your body burns at complete rest — using the Mifflin-St Jeor equation. You enter your sex, age, height, and weight, and the calculator returns your daily maintenance calories (the amount needed to hold your current weight) as well as your BMR. This is the same formula most dietitians and clinical guidelines use when estimating energy needs.

Formula

The Mifflin-St Jeor equation is the standard formula used to estimate resting energy expenditure. It has separate versions for men and women:

• Men: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age in years) + 5
• Women: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age in years) − 161

In the calculator above, the sex drop-down adds 166 for men and subtracts 161 for women (the +5 for men is included in the 166). The variables are:

• weight — your body mass in kilograms (1 kg = 2.2 lb)
• height — your height in centimeters (1 inch = 2.54 cm)
• age — your age in years
• BMR — basal metabolic rate in kcal/day, the energy your body uses at rest for breathing, circulation, and cell maintenance

The maintenance calories output multiplies your BMR by an activity factor of 1.375, which corresponds to light exercise (1–3 days per week). That gives you the approximate calories needed to keep your weight stable at that activity level.

Worked Example

Let’s use the default values from the calculator: a 30-year-old man, 175 cm tall, weighing 70 kg.

1. Plug the numbers into the men’s formula: BMR = (10 × 70) + (6.25 × 175) − (5 × 30) + 5
2. Calculate each part: 10 × 70 = 700; 6.25 × 175 = 1093.75; 5 × 30 = 150
3. Add and subtract: 700 + 1093.75 − 150 + 5 = 1648.75
4. Round to the nearest whole number: 1649 kcal/day

The calculator’s first output shows 1649 kcal/day, matching the hand calculation. The maintenance output is 1649 × 1.375 = 2267.375, rounded to 2267 kcal/day.

Why the Mifflin-St Jeor Equation?

The Mifflin-St Jeor equation was published in 1990 and has largely replaced the older Harris-Benedict formula (from 1919) because it is more accurate for modern populations. A widely cited 2005 study in the Journal of the American Dietetic Association compared several predictive equations against indirect calorimetry and found Mifflin-St Jeor agreed best with measured resting metabolic rate in both normal-weight and obese adults. It is now the recommended equation in many clinical nutrition guidelines, including those from the Academy of Nutrition and Dietetics.

That said, it is still an estimate. Individual BMR varies with muscle mass, genetics, thyroid function, and body composition. Two people with identical age, height, and weight can have different true BMRs. The formula gives you a starting point, not a precise measurement.

How to Read the Results

The BMR number is the energy you would burn if you stayed in bed all day. Your actual daily burn is higher because of physical activity, digestion, and everyday movement. To estimate total daily energy expenditure (TDEE), you multiply BMR by an activity factor:

• Sedentary (little or no exercise): BMR × 1.2
• Lightly active (1–3 days/week): BMR × 1.375
• Moderately active (3–5 days/week): BMR × 1.55
• Very active (6–7 days/week): BMR × 1.725
• Extra active (physical job + hard training): BMR × 1.9

The calculator uses 1.375 as a default, but you can mentally adjust if your activity level differs. To lose weight, you typically eat below your TDEE; to gain weight, you eat above it. A common safe target is 300–500 kcal/day deficit or surplus, but individual needs vary.

Common Mistakes and Limitations

Several mistakes can throw off your result:

• Using pounds and inches without converting. The formula requires kilograms and centimeters. If you enter 175 lb instead of 175 kg, the result is wildly wrong. Convert first: 1 lb = 0.4536 kg, 1 inch = 2.54 cm.
• Confusing BMR with TDEE. BMR is just the resting component. If you use BMR as your calorie target, you will under-eat for your actual activity level.
• Rounding too early. Keep the full decimal until the end, then round. The calculator does this for you.
• Assuming the result is a hard number. It is an estimate with a typical error of about 200–300 kcal/day either way. Use it as a baseline and adjust based on your weight trend over a few weeks.

The formula also does not account for body fat percentage. A very muscular person will have a higher true BMR than the formula predicts, while someone with high body fat may have a lower one. For most people, though, Mifflin-St Jeor is close enough for practical nutrition planning.

Alternatives to the Me Formula

If you want a more individualized estimate, there are other options:

• Katch-McArdle formula: Uses lean body mass instead of total weight. BMR = 370 + (21.6 × lean body mass in kg). More accurate for athletes, but requires knowing your body fat percentage.
• Harris-Benedict equation: The older 1919 formula, still used in some older textbooks. It tends to overestimate BMR by about 5% in modern populations.
• Indirect calorimetry: A clinical test where you breathe into a machine that measures oxygen consumption and carbon dioxide production. This is the gold standard, but it is expensive and not available to most people.
• Wearable devices: Fitness trackers estimate TDEE using heart rate and movement data, but accuracy varies widely and they often overestimate calorie burn.

For most people, Mifflin-St Jeor is the best free, quick estimate available. If you are an athlete or have unusual body composition, consider the Katch-McArdle formula or a professional assessment.

Frequently Asked Questions

Is the Me formula the same as the Mifflin-St Jeor equation?

Yes, “Me formula” is a shorthand for the Mifflin-St Jeor equation, which calculates basal metabolic rate. It is sometimes called the “Mifflin formula” or “Mifflin-St Jeor.” The name comes from the researchers who developed it in 1990.

How accurate is the Me formula for weight loss?

It is accurate enough to give you a useful starting calorie target for most people. Studies show it predicts measured BMR within about 10% for the majority of adults. However, individual variation means you may need to adjust your intake up or down based on how your weight changes over 2–4 weeks.

Do I use my total weight or lean body mass?

For the Me formula, you use total body weight in kilograms. It does not require body fat percentage. If you know your lean body mass, the Katch-McArdle formula may be more accurate, but it is not the same equation.

Should I use the male or female formula?

Use the formula that matches your biological sex at birth, as the equations were developed and validated on that basis. People who are transgender and on hormone therapy may find their BMR shifts slightly, but there is no separate validated formula for that; the standard equation is still a reasonable estimate.

Can I use the Me formula if I am over 60?

Yes, the Mifflin-St Jeor equation was validated in adults aged 19–78, so it applies to older adults. However, BMR naturally declines with age partly due to loss of muscle mass. The formula accounts for age, but if you are very frail or very muscular, your actual BMR may differ.

Why does my fitness tracker give a different number?

Fitness trackers use proprietary algorithms that combine your profile with heart rate and movement data. They often estimate total daily burn, not just BMR, and they frequently overestimate. The Me formula gives a resting estimate; the tracker gives an activity-inclusive estimate, so they are not directly comparable.

Related

• Z to EST Time Converter: Quick & Accurate
• Dividend Yield Formula Calculator & Guide
• Time Converter US to India: IST Made Easy

in sex | Sex | Male=1, Female=0 | 1 | 0
in age | Age | years | 30 | 18
in h | Height | cm | 175 | 100
in w | Weight | kg | 70 | 30
out bmr | BMR | kcal/day | (10 * w) + (6.25 * h) - (5 * age) + (sex * 166) - 161 | 0
out maint | Maintenance calories | kcal/day | bmr * 1.375 | 0