Calorie calculator · Weight loss
How many calories to lose weight?
Work out your calorie target for the diet: TDEE per Mifflin-St Jeor minus a moderate deficit — plus the amount of protein that protects your muscle along the way.
Your calorie target for weight loss
And who's going to count that every day?
Myron tracks your calorie target for you — you speak, the AI logs. "Scrambled eggs from three eggs and two slices of whole-grain bread" is all it takes.
How this calculator works
It's built on the Mifflin-St Jeor equation, which estimates your basal metabolic rate from weight, height, age and sex — the most reliable of the common formulas in comparison studies. Your BMR is multiplied by your activity factor (PAL) to get your total daily energy expenditure. Depending on your goal, the calculator subtracts a moderate deficit or adds a surplus — converted at ~7,700 kcal per kilogram of body mass.
| Activity level | Factor |
|---|---|
| Sedentary, little training | 1.2 |
| Lightly active | 1.375 |
| Moderately active | 1.55 |
| Very active | 1.725 |
| Extremely active | 1.9 |
The macro recommendation follows sports science instead of rigid percentages: protein by body weight and goal (1.8–2.4 g/kg), fat as a baseline (0.9 g/kg), and the rest goes to carbs — your fuel for training.
Frequently asked questions
How big should my calorie deficit be?
For most people, 300–500 kcal below TDEE is the best compromise — about 0.25–0.5 kg per week. Bigger deficits work short-term but raise the risk of muscle loss, cravings and giving up.
How fast can I lose weight healthily?
As a rule of thumb: 0.5–1 % of body weight per week. What matters is the weight trend over two to three weeks, not the scale's daily readings — those swing with water and gut content by a multiple of the actual fat loss.
Why am I not losing weight despite a calorie deficit?
Usually the deficit is smaller than you think: expenditure gets overestimated, intake underestimated (oil, drinks, snacks on the side). On top of that, water retention can mask fat loss for weeks. Track consistently for two to three weeks, look at the trend, then adjust.
Should I eat below my BMR?
Not advisable long-term: very large deficits cost a disproportionate amount of muscle and performance and are hard to sustain. A moderate deficit below your TDEE — not below your BMR — gets you there more sustainably.
Formula: Mifflin MD, St Jeor ST et al. (1990): A new predictive equation for resting energy expenditure in healthy individuals — more under Methodology & data sources. More to look up: calorie tables · exercise directory.