How do I calculate my calorie needs?

Your calorie needs are calculated in two steps: First, your Basal Metabolic Rate (BMR) is determined — the calories your body burns at rest. Then, this is multiplied by an activity factor (PAL) to get your Total Daily Energy Expenditure (TDEE). Our calculator uses the Mifflin-St Jeor formula by default and optionally the Katch-McArdle formula if you know your body fat percentage.

What is the difference between BMR and TDEE?

BMR (Basal Metabolic Rate) is the energy your body needs at complete rest to maintain vital functions like breathing, heartbeat, and cell regeneration. TDEE (Total Daily Energy Expenditure) additionally includes calories burned through movement, exercise, digestion (thermic effect of food), and general activity. For dieting or meal planning, TDEE is the relevant metric.

How many calories do I need to lose weight?

To lose weight, you need to consume fewer calories than your TDEE. A moderate deficit of 500 kcal per day leads to weight loss of about 0.5 kg per week. We recommend never going below your BMR and keeping the deficit between 300-750 kcal daily to lose weight sustainably without muscle loss.

What is the Mifflin-St Jeor formula?

The Mifflin-St Jeor formula is the most commonly recommended equation for calculating BMR today. Developed in 1990, it is considered the most accurate formula for most people. For men: BMR = 10 x weight(kg) + 6.25 x height(cm) - 5 x age(years) + 5. For women: same formula but -161 instead of +5. It accounts for gender, weight, height, and age.

How accurate is a calorie calculator?

Calorie calculators provide a good estimate with approximately 80-90% accuracy for most people. The Mifflin-St Jeor formula has an average deviation of about 10% from actual BMR. Factors like genetics, hormones, medications, and body composition can influence actual needs. If you enter your body fat percentage, the more accurate Katch-McArdle formula is used.

Should I eat below my BMR?

No, you should never eat below your BMR consistently. BMR only covers vital body functions. Calorie intake below BMR can lead to muscle loss, nutrient deficiency, metabolic slowdown, and hormonal imbalances. Our calculator sets a floor of 1,200 kcal. A moderate deficit below TDEE but above BMR is the safe approach.

How much protein do I need per day?

We recommend 1.8 g protein per kilogram of body weight per day. For muscle building (goal: gain weight), we increase the recommendation to 2.0 g/kg. Protein is crucial for muscle maintenance, satiety, and the thermic effect of food. At 75 kg body weight, that means 135 g protein daily — about 540 kcal from protein alone.

How often should I recalculate my calorie needs?

You should recalculate every 4-6 weeks, especially if your weight has changed by more than 2-3 kg, you've changed your training program, or you've hit a plateau. As body weight decreases, your BMR also decreases, so you need fewer calories than at the start of your diet.

Are 1,200 calories per day enough?

1,200 kcal per day is the absolute minimum and only suitable for very small, light, and inactive individuals. For most people, this intake is too low and can lead to nutrient deficiencies. Women should consume at least 1,400-1,600 kcal and men at least 1,600-1,800 kcal daily. Our calculator considers your individual measurements and never sets an extreme deficit.

How does exercise affect my calorie needs?

Exercise significantly increases your TDEE. Depending on activity level, your BMR is multiplied by a PAL factor: Sedentary (1.2), Lightly active (1.375), Moderately active (1.55), Very active (1.725), Extremely active (1.9). Additionally, our calculator accounts for daily steps: above 7,000 steps, you get a bonus of 0.04 kcal per extra step. This accurately captures everyday movement too.

How to Calculate a Calorie Deficit Correctly for Sustainable Weight Loss | Calorie Calculator

How to Calculate a Calorie Deficit Correctly: Sustainable Weight Loss Without the Yo-Yo Effect

A calorie deficit is the fundamental requirement for any weight loss. But how large should it be? And why do so many diets fail despite a calorie deficit? In this article, we explain the science behind calorie deficits and give you a practical roadmap.

What Is a Calorie Deficit?

A calorie deficit occurs when you consume fewer calories than your body expends. Your body must then draw on stored energy -- ideally fat reserves. The energy density of body fat is approximately 7,700 kcal per kilogram. This means: to lose 1 kg, you need to create a total deficit of 7,700 kcal.

The Three Levels of Calorie Deficit

**Mild deficit (-300 kcal/day):** Ideal for beginners and those with little weight to lose. Weight loss: about 0.3 kg per week. Advantage: minimal hunger, easy to maintain, minimal muscle loss. Disadvantage: slow progress.

**Moderate deficit (-500 kcal/day):** The golden middle ground and the most common recommendation. Weight loss: about 0.5 kg per week. Advantage: good balance between speed and sustainability. Disadvantage: requires conscious dietary changes.

**Aggressive deficit (-750 kcal/day):** For experienced individuals with significant body weight to lose. Weight loss: about 0.75 kg per week. Advantage: fast visible results. Disadvantage: higher risk of muscle loss, hunger, and dropout.

Why You Should Never Eat Below Your BMR

BMR is the energy your body needs for vital functions. Chronic calorie intake below BMR can lead to adaptive thermogenesis: your body downregulates metabolism to conserve energy. Studies on participants of The Biggest Loser showed that extreme calorie deficit can reduce BMR by up to 500 kcal below expected values -- and this effect persisted years after the show.

The Role of Protein in a Deficit

Adequate protein is crucial for maintaining muscle mass during a deficit. A meta-analysis by Helms et al. (2014) recommends 1.6-2.4 g protein per kg body weight when in a deficit. Our calculator sets 1.8 g/kg as the default, which is optimal for most people. Protein also has the highest thermic effect of all macronutrients: up to 30% of protein calories are burned during digestion alone.

Breaking Through Plateaus

After several weeks of dieting, weight often stagnates. This is normal and has several causes: water retention can mask fat loss, metabolism adapts, and with decreasing body weight, calorie needs also decrease. Solution: recalculate your calorie needs every 4-6 weeks and adjust your deficit. Sometimes a 1-2 week diet break at maintenance calories also helps.

Practical Tips for a Sustainable Deficit

- Replace calorie-dense with nutrient-dense foods: vegetables, fruits, lean protein, and whole grains are more satiating.

- Plan your meals ahead to avoid impulse purchases and uncontrolled eating.

- Move more in daily life: 2,000 extra steps per day burn about 80-100 extra kcal.

- Sleep enough: sleep deprivation increases the hunger hormone ghrelin and decreases the satiety hormone leptin.

- Be patient: 0.5 kg per week equals 26 kg in one year -- that is transformative.

Conclusion

A calorie deficit of 300-500 kcal per day is the optimal path to weight loss for most people. Ensure adequate protein, exercise regularly, and recalculate your needs periodically. Sustainable weight loss is a marathon, not a sprint.