Free tool · Scientifically proven · 2026

Calculate your
daily calorie requirements

Discover in less than 30 seconds how many calories you need to lose weight, maintain your weight, or build muscle mass.

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Mifflin-St Jeor formula Scientifically proven 100% free · no account required Belgian webshop

Enter your details

Age years

Weight kg

Length cm

Activity level

Fill in all the fields correctly to calculate your result.

§ 02 · Your result

Your personal calorie needs

Calculated using the Mifflin-St Jeor formula — the most accurate method for the majority of people.

Weight loss — kcal per day

Calorie deficit

−500 kcal/day below your maintenance level. Sustainable fat loss of ∼0.5 kg per week.

Your baseline Maintain weight — kcal per day

Maintenance calories

This is your energy balance at zero. Eat this daily to maintain your weight.

Muscle building — kcal per day

Calorie surplus

+300 kcal/day above maintenance. Optimal for muscle growth with minimal fat gain.

What do
your calories mean?

Weight loss

A calorie deficit of 300–500 kcal per day leads to gradual and sustainable fat loss. Combine this with sufficient protein and strength training to maintain muscle mass while losing weight.

−300 to −500 kcal / day

Maintenance

At your maintenance calories, you eat exactly what you burn. Your weight stays stable. This is your starting point for any calorie strategy — know this number and build on it.

Energy balance = zero

Muscle building

A surplus of 200–400 kcal gives your body the energy to build muscle tissue. Combine with heavy progressive training and 1.6–2.2 g of protein per kg of body weight.

+200 to +400 kcal / day

Frequently Asked Questions

Everything you need to know about calorie requirements and how to apply this in practice.

How accurate is this calculator?

Our calculator uses the Mifflin-St Jeor formula — scientifically the most accurate method for calculating the basal metabolic rate (BMR). For most people, the margin of error is 5–10%. Factors such as muscle mass, hormones, and genetics can affect your actual needs. Use the result as a starting point and adjust it based on your weight changes over 2–3 weeks.

What exactly are maintenance calories?

Maintenance calories (also TDEE — Total Daily Energy Expenditure) are the number of calories your body burns daily, including all your activities. If you eat exactly this amount, your weight will not change. This is the energy balance at zero — the starting point for any nutrition strategy, whether you want to lose or gain weight.

How many calories should I eat to lose weight?

Eat 300–500 kcal fewer than your maintenance calories per day. This leads to a fat loss of ~0.3–0.5 kg per week — safe and sustainable in the long term. Larger deficits lead to muscle loss, a slowed metabolism, and are harder to maintain. Ensure at least 1.6 g of protein per kg of body weight to protect your muscle mass.

How many calories do I need for muscle building?

For effective muscle building, you need a daily surplus of 200–400 kcal above your maintenance calories. Combine this with progressive resistance training and a protein intake of 1.6–2.2 g per kg of body weight. Too large a surplus primarily leads to fat gain—more calories do not translate into additional muscle growth after a certain point.

What is a calorie deficit?

A calorie deficit occurs when you eat fewer calories than your body burns daily. Your body then uses stored fat reserves as an energy source, which leads to weight loss. A deficit of ~3,500 kcal over a week is equivalent to losing about 0.5 kg of body fat.

How often should I recalculate my calories?

Recalculate every 4–6 weeks, or whenever your weight has changed significantly (±3–4 kg). As you lose or gain weight, your calorie needs also change. Recalculating regularly keeps your nutrition strategy accurate and effective — especially during a long-term journey spanning several months.