Estimate the calories you burn each day with the Mifflin-St Jeor equation, plus target calories for mild weight loss, maintenance, and weight gain.
Maintenance (TDEE)
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Mild loss (−500)
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Mild gain (+500)
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How It Works
Your Basal Metabolic Rate (BMR) is the energy your body uses at rest. The Mifflin-St Jeor equation estimates it from weight, height, age, and sex: for males, BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5; for females, BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161.
Your Total Daily Energy Expenditure (TDEE) is BMR multiplied by an activity factor: 1.2 for sedentary, 1.375 for light exercise, 1.55 for moderate, 1.725 for active, and 1.9 for very active. Eating around your TDEE maintains your current weight.
A pound of body fat is roughly 3,500 calories, so a daily deficit or surplus of about 500 calories tends to produce around one pound of weight change per week. The calculator shows maintenance plus minus-500 targets for mild loss and gain.
Worked example: a 30-year-old male, 175 cm, 75 kg, with moderate activity has BMR = 10×75 + 6.25×175 − 5×30 + 5 = 1,724 kcal. TDEE = 1,724 × 1.55 ≈ 2,672 kcal. A mild-loss target is about 2,172 kcal/day and a mild-gain target about 3,172 kcal/day.
Frequently Asked Questions
Which activity level should I pick?
Sedentary means little or no exercise, light means 1–3 days a week, moderate means 3–5 days, active means 6–7 days, and very active means hard daily exercise or a physical job.
How accurate is the Mifflin-St Jeor equation?
It is one of the most accurate widely-used formulas, but any estimate can be off by 5–10% because individual metabolism varies. Use the numbers as a starting point and adjust based on real results.
Are the loss and gain targets safe?
A 500-calorie daily shift is a gentle, sustainable pace for most adults. Very aggressive deficits or surpluses should be discussed with a healthcare provider or registered dietitian.
What is the difference between BMR and TDEE?
BMR is what you would burn lying in bed all day doing nothing. TDEE multiplies BMR by an activity factor to estimate what you actually burn including daily movement and exercise.
How many calories should I eat to lose 2 lb per week?
Two pounds per week requires about a 1,000-calorie daily deficit, which is aggressive and hard to sustain. Make sure your intake stays above roughly 1,200 kcal (women) or 1,500 kcal (men) and consult a provider before attempting it.
Should I eat back the calories my fitness tracker shows?
Trackers often overestimate exercise calories by 10–30%. If you want to account for a workout, start by eating back half the reported calories and adjust based on how your weight trends over a couple of weeks.