Find out exactly how many calories you should eat each day — based on your age, body size, activity level, and personal goal — whether that is losing fat, maintaining weight, or building muscle.
Fill in your details, activity level, and goal — we will show your daily calorie target and full breakdown.
The basics
A calorie calculator estimates how many calories your body needs each day to maintain, lose, or gain weight. It combines your Basal Metabolic Rate (BMR) — the energy your body uses at rest — with an activity multiplier to produce your Total Daily Energy Expenditure (TDEE). From there, a goal-specific adjustment gives you a personalised daily calorie target.
There is no single universal answer — calorie needs depend on your age, sex, height, weight, and how active you are. As a general guide, many adults fall within the following ranges, but individual variation can be significant:
This calculator uses the Mifflin-St Jeor equation — the most validated formula for the general population. It first calculates your BMR from age, sex, height, and weight. That BMR is then multiplied by an activity factor (ranging from 1.2 for sedentary to 1.9 for extremely active) to produce your TDEE. Finally, a goal-based adjustment is applied: typically a 500 kcal deficit for weight loss or a 300–500 kcal surplus for muscle gain.
To lose body fat, you need a sustained calorie deficit — consuming less than you burn. A deficit of 500 kcal/day leads to approximately 0.45 kg (1 lb) of fat loss per week. This rate is considered safe and sustainable for most people. Avoid going below 1,200 kcal/day (for women) or 1,500 kcal/day (for men) without medical supervision, as very low intake increases the risk of muscle loss, nutritional deficiency, and metabolic slowdown.
Building muscle requires a calorie surplus on top of adequate protein intake (1.6–2.2 g/kg bodyweight) and consistent resistance training. A modest surplus of 200–500 kcal/day above your TDEE provides the extra energy for tissue synthesis without excessive fat gain. Larger surpluses beyond this range tend to add more fat than muscle. Progress requires patience — optimal muscle gain is typically 0.5–2 kg per month under ideal conditions.
Calories measure total energy. Macros (macronutrients) describe where those calories come from: protein (4 kcal/g), carbohydrates (4 kcal/g), and fat (9 kcal/g). For weight management, total calories are most important. For body composition, athletic performance, or specific health goals, the distribution of macros becomes increasingly significant. Use this calculator to set your calorie target, then use the Macro Calculator to break it into protein, carbs, and fat.
Calorie needs vary because of body size, muscle mass, age, hormones, genetics, and activity patterns. Two people of the same weight and height can have meaningfully different metabolic rates due to differences in muscle-to-fat ratio and thyroid function. This is why calculators provide estimates, not exact targets — real-world adjustments based on progress over two to four weeks are essential.
FAQ
To lose weight, you need to consume fewer calories than your body burns each day — creating a calorie deficit. A deficit of 500 calories per day typically leads to around 0.45 kg (1 lb) of fat loss per week. This is considered a safe, sustainable rate. Very large deficits (more than 750–1,000 kcal/day) risk muscle loss, nutrient deficiency, and metabolic adaptation. Always aim to stay above your BMR and consult a healthcare professional for personalised guidance.
Calorie calculators based on the Mifflin-St Jeor equation — the one used here — are accurate within roughly 10% for most people in the general population. The equation accounts for age, sex, height, and weight. Individual variation in body composition (muscle-to-fat ratio), thyroid function, gut microbiome, and genetics means real needs can differ. Treat the result as a well-informed starting point, then adjust based on real-world results over two to four weeks.
Calories are the primary driver of weight change over time. Consuming more than you burn leads to weight gain; consuming less leads to weight loss. However, the quality of calories matters too — protein and fibre promote satiety, and highly processed foods can disrupt appetite regulation. Hormones, sleep quality, and stress also influence how the body uses and stores calories. For most people, though, managing calorie intake is the most reliable lever for weight management.
Yes — on average, men need more calories than women of the same age, height, and weight. This is primarily because men tend to carry more lean muscle mass, which is metabolically active and burns more calories at rest. The Mifflin-St Jeor equation accounts for this biological difference directly. That said, individual activity levels and goals matter far more than sex alone — an active woman may easily outpace the calorie needs of a sedentary man.
Yes, significantly. Physical activity adds calories burned on top of your BMR. The more intense and frequent your exercise, the higher your Total Daily Energy Expenditure (TDEE). Our calculator adjusts for this using activity multipliers ranging from 1.2 (sedentary) to 1.9 (extremely active). If you increase your exercise frequency, you should reassess your calorie target to ensure you are fuelling your training and recovery appropriately.
Counting calories can be a very effective tool for building awareness of your food intake, especially when starting a new nutrition plan. Research shows that people who track their intake are more likely to achieve and maintain their goals. However, it is not necessary for everyone — intuitive eating, focusing on food quality, and building healthy habits can work just as well for those who find calorie counting stressful. Use it as a tool, not a lifelong obligation.
Consistently eating too few calories — especially below your BMR — can have serious consequences. Your body responds by breaking down muscle tissue for energy, slowing your metabolism (adaptive thermogenesis), impairing hormone production, weakening the immune system, and causing nutrient deficiencies. Over time, very low calorie intake can impair bone density, reproductive function, and cognitive performance. A deficit of 300–500 kcal below TDEE is the recommended range for safe, sustainable fat loss.
Building muscle requires a calorie surplus — consuming more calories than you burn. A modest surplus of 200–500 kcal/day above your TDEE, combined with adequate protein (1.6–2.2 g/kg bodyweight) and consistent resistance training, supports lean muscle growth. Larger surpluses tend to result in more fat gain than additional muscle. Progress is slow: even under optimal conditions, most people can gain 0.5–2 kg of muscle per month.
As you age, your Basal Metabolic Rate gradually declines — typically 1–2% per decade after age 30. The main reasons are a natural reduction in lean muscle mass (sarcopenia) and hormonal shifts that reduce the rate of cellular repair and energy turnover. Regular resistance training can significantly slow this decline by preserving muscle. Our calculator accounts for age directly in its formula, so your estimate reflects your current phase of life.
Calories measure total energy from food. Macros (macronutrients) describe where those calories come from: protein (4 kcal/g), carbohydrates (4 kcal/g), and fat (9 kcal/g). Managing calories tells you how much energy to eat; managing macros tells you how to distribute that energy. For weight management alone, total calories matter most. For body composition, performance, or specific health goals, the macro split becomes increasingly important alongside calorie targets.
Keep exploring
Your calorie target is just the start. These free Fitlydoo tools help you build the complete nutrition picture.
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