Calorie Calculator
Your body burns a fairly predictable number of calories per day — basal metabolism plus what you spend on activity. Enter age, sex, height, weight and activity level, and the calculator returns your maintenance calories (neither lose nor gain), plus targets for slow, moderate and aggressive weight loss or muscle gain. The numbers are starting points; the scale tells you if they need adjusting.
How daily calorie targets are estimated
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1
Enter stats
Age, sex, height, weight. Metric or imperial.
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2
Pick activity level
Sedentary desk job through very active manual labour or multi-hour training.
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3
Choose your goal
Lose, maintain, recomp or gain. Each goal adjusts the calorie target by a specific percentage of TDEE.
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4
Read target and macros
Daily calories plus suggested macro split (protein prioritised, fats moderate, carbs filling the remainder).
The calculation chain
- BMR via Mifflin-St Jeor:
- Men: BMR = 10·kg + 6.25·cm − 5·age + 5
- Women: BMR = 10·kg + 6.25·cm − 5·age − 161
- TDEE = BMR × activity factor (1.2 sedentary → 1.9 extremely active)
- Goal calories = TDEE ± deficit/surplus
Goal presets
| Goal | Adjustment | Expected result |
|---|---|---|
| Slow loss | −10% of TDEE | ~0.25 kg / week |
| Moderate loss | −20% of TDEE | ~0.5 kg / week |
| Aggressive loss | −25% of TDEE | ~0.75 kg / week (harder to sustain) |
| Maintenance | 0 | weight holds |
| Lean recomp | −5% of TDEE + high protein | slow loss with muscle retention |
| Slow gain | +10% of TDEE | ~0.25 kg / week |
| Aggressive bulk | +20% of TDEE | ~0.5 kg / week, more fat gain |
Macro split
- Protein: 1.6-2.2 g per kg of body weight. Highest priority — preserves muscle in a deficit, builds it in a surplus.
- Fat: 0.6-1.0 g per kg body weight floor (hormonal health).
- Carbs: the remainder. Higher carbs suit endurance athletes and heavy lifters; lower carbs suit some with insulin sensitivity issues.
Reality check
- Measured calorie burn can differ ±20% from the estimate — metabolism, NEAT (fidgeting), and tracker inaccuracy all add noise.
- Weight also shifts from water and glycogen short-term. Judge results over 2-3 weeks of daily weighing, not day-to-day.
- Recalculate every 4-5 kg of loss or gain. The formula uses current weight; as you get lighter, maintenance drops.
Safety floor
Don’t drop below ~1,500 kcal/day for men or ~1,200 kcal/day for women without medical supervision. Below those levels, lean mass loss accelerates and hormonal disruption is common.
Frequently Asked Questions
Pick the lower of two bands you’re unsure about — most people overestimate. Sedentary: mostly desk. Light: 1-3 workouts/week. Moderate: 3-5. Active: 6-7. Very active: manual labour + daily training.
If you used TDEE with an activity multiplier, exercise is already included — do not eat it back on top. If your TDEE was “sedentary” and you exercise separately, add back about 60-70% of tracker-reported exercise calories (trackers overestimate).
Metabolic adaptation plus likely underestimation of food intake. Re-measure portions, recalculate TDEE with your current weight, and consider a diet break of 1-2 weeks at maintenance before resuming.
Approximately, yes. That’s the “calorie in the fat plus metabolic cost” figure often cited. In practice, a 7,700 kcal weekly deficit rarely produces exactly 1 kg of scale loss because water and glycogen shift alongside fat.