Calorie Calculator
This calculator turns your body data and activity level into a daily calorie target for losing, maintaining or gaining weight. It is the practical version of the TDEE calculation: one number to eat against, adjusted for the direction you actually want to go.
Inputs
Result
2,556 kcal/day
Lose weight 2,056 kcal · Gain weight 3,056 kcal
How the calorie calculator works
Start from BMR via Mifflin-St Jeor, multiply by your activity factor for maintenance calories, then apply your goal adjustment.
Typical adjustments: −20% for weight loss, −10% for slow loss, +10% for lean gain, +20% for a faster bulk.
One kilogram of fat stores about 7,700 kcal, so a 550 kcal daily deficit is roughly 0.5 kg a week in theory — and about 0.4 kg in practice once adaptation is included.
Worked example: maintenance 2,600 kcal
- Slow loss at −10%: 2,340 kcal, about 0.25 kg a week.
- Standard loss at −20%: 2,080 kcal, about 0.5 kg a week.
- Lean gain at +10%: 2,860 kcal, about 0.25 kg a week.
- Over twelve weeks, the standard deficit predicts around 6 kg.
- Actual results usually land 10–15% short of prediction because expenditure falls as weight does.
Common mistakes to avoid
Setting the target too low
Very low intakes cause muscle loss, hormonal disruption and binge cycles. Rarely go below 1,200 kcal for women or 1,500 for men without supervision.
Eating back exercise calories twice
Your activity factor already accounts for training. Adding a watch's burn on top routinely erases the entire deficit.
Ignoring liquid calories
Juice, sweetened coffee and alcohol are easy to omit from a log and can quietly account for 300–600 kcal a day.
Frequently asked questions
How many calories should I eat to lose weight?
About 10–20% below your maintenance figure. For a 2,600 kcal maintenance that is 2,080–2,340 kcal, giving 0.25–0.5 kg of loss a week.
Is 1,200 calories a day safe?
It is a common floor for women under supervision but is too low for most active adults and makes adequate protein and micronutrients hard to reach.
Do I need to count calories forever?
No. Most people track for a few months to calibrate portions, then maintain with habits and periodic check-ins.
Does meal timing affect the total?
Total intake dominates. Timing influences hunger, training performance and adherence, which matter indirectly but do not change energy balance.
Why am I gaining weight in a deficit?
Usually water retention from new training, higher sodium or carbohydrate intake, or the menstrual cycle. Judge by weekly averages over three weeks.
Related calculators
TDEE Calculator
Total daily energy expenditure from BMR and activity.
BMR Calculator
Basal metabolic rate using the Mifflin-St Jeor equation.
Macro Split Calculator
Turn a calorie target into protein, carb and fat grams.
Protein Intake Calculator
Daily protein target based on weight and goal.
BMI Calculator
Body Mass Index from height and weight, with WHO category.