Calculate your daily calorie needs instantly
This free calorie calculator helps you determine your daily calorie needs based on your personal data and activity level. It uses the Mifflin-St Jeor equation to calculate your Basal Metabolic Rate (BMR) and then adjusts for your activity level to find your Total Daily Energy Expenditure (TDEE).
The average adult needs between 1,600 and 3,000 calories per day depending on age, sex, height, weight, and activity level. Women typically need 1,600–2,400 calories and men need 2,000–3,000. However, your personal TDEE (Total Daily Energy Expenditure) is the most accurate guide — this calculator uses the Mifflin-St Jeor equation, which is the most widely validated formula for most people.
A deficit of 500 calories per day leads to approximately 0.5kg (1lb) of fat loss per week, since 3,500 calories equals roughly 1lb of fat. For safe, sustainable weight loss, aim for a deficit of 500–750 calories per day. Avoid going below 1,200 calories (women) or 1,500 calories (men) without medical supervision, as this can cause muscle loss and nutrient deficiencies.
BMR (Basal Metabolic Rate) is the number of calories your body burns at complete rest — just to keep your heart beating, lungs breathing, and organs functioning. TDEE (Total Daily Energy Expenditure) is your BMR multiplied by an activity factor. TDEE is the number you should use for daily calorie planning, as it accounts for the energy you burn through movement and exercise.
Macronutrients (macros) are protein, carbohydrates, and fat — the three major sources of calories. A common starting split for general health is 30% protein, 40% carbohydrates, and 30% fat. For weight loss, higher protein (35–40%) helps preserve muscle. For endurance athletes, higher carbs (50–60%) support performance. Each gram of protein and carbs contains 4 calories; each gram of fat contains 9 calories.
Yes — the more active you are, the higher your TDEE and the more calories you can eat while maintaining or losing weight. However, most people significantly overestimate calories burned during exercise. A 30-minute jog burns roughly 250–350 calories for an average adult — equivalent to one medium muffin. Use the activity level multiplier in this calculator rather than adding individual workout calories for more accurate results.
Your TDEE is not fixed. Several factors cause it to shift — sometimes significantly — over months and years.
Age: BMR tends to decline by roughly 1–2% per decade after age 20, partly due to gradual muscle loss. This is why a 50-year-old and a 25-year-old of identical height, weight, and activity level have different calorie needs.
Muscle mass: Muscle burns around 6 calories per pound per day at rest, versus about 2 calories for fat. Strength training can raise your BMR over time — even without significant weight change — because more muscle means a higher baseline calorie burn. People who lose weight through diet alone (losing muscle alongside fat) often find weight management harder over the long run as a result.
Adaptive thermogenesis: When you reduce calories significantly, your body responds by becoming more efficient — burning slightly fewer calories for the same functions. This is one reason weight loss often slows after an initial period, even with a consistent deficit. Recalculating your TDEE every time your weight changes by 5–10 lbs helps keep your targets accurate.
The activity multiplier is the biggest single source of error in TDEE estimates. Most people overestimate their activity level, which leads to eating more than they burn.
Sedentary means a desk job and little deliberate exercise — most office workers fall here. Lightly active means 1–3 gym sessions per week alongside an otherwise sedentary lifestyle. Moderately active applies to consistent exercise 3–5 days per week at moderate intensity. Very active covers daily intense exercise or a physically demanding job. Extremely active is for competitive athletes or those with consistently high training volumes.
If you are unsure, choose one level lower than you think. It is easier to eat slightly more if you are losing weight too fast than to undo a persistent surplus that stalls progress.
The widely cited rule that a 500-calorie daily deficit produces 1 lb of fat loss per week is based on the assumption that 3,500 calories equals 1 lb of body fat. In practice, results vary. The rule tends to hold reasonably well for moderate deficits in people with significant fat to lose. For leaner individuals, the body resists fat loss more aggressively and may burn proportionally more muscle tissue to compensate.
For most people, a deficit of 20–25% of TDEE strikes the best balance between rate of fat loss and preservation of muscle. Going below 1,200 calories per day (women) or 1,500 calories per day (men) is rarely advisable without medical supervision — extreme restriction typically leads to muscle loss, micronutrient deficiencies, and metabolic adaptation that makes long-term weight management harder.
The macro split shown in the results (30% protein, 40% carbs, 30% fat) is a general-purpose starting point, not a rigid prescription. What matters most for weight management is total calorie intake — macro ratios have a smaller effect on fat loss than total energy balance. That said, higher protein intake (0.7–1g per lb of body weight) is consistently associated with better muscle retention during a calorie deficit and stronger satiety signals, making it easier to stick to a reduced-calorie plan.
Carbohydrates are the body's preferred fuel for moderate-to-high intensity exercise. If you train regularly, keeping carbs on the higher end (45–55% of calories) supports performance and recovery. Fat should not drop below about 20% of total calories, as dietary fat is essential for hormone production, fat-soluble vitamin absorption, and joint health.
This calculator uses the Mifflin-St Jeor equation (1990), which research by the Academy of Nutrition and Dietetics identifies as the most accurate single BMR formula for most adults. Activity multipliers follow the established Harris-Benedict activity factor framework. Macro recommendations reflect standard sports nutrition guidelines from the American College of Sports Medicine. Results are estimates — individual variation is significant, and a registered dietitian can provide personalised targets.
Figures are estimates for guidance only. See about this site — how we source data and what these tools can and cannot do.
Researched and maintained by Iulian, founder of Flux Media Systems. General information, not professional advice — about this site & our sources →