How many calories do you actually need?
Your daily calorie need is the energy your body burns in a day — known as your Total Daily Energy Expenditure (TDEE). Eat that amount and your weight holds steady. Eat below it and you lose fat; eat above it and you gain. This calculator builds your number in three steps: your resting burn, your activity, and your goal.
Step 1 — Basal Metabolic Rate (BMR)
Your BMR is what you'd burn lying in bed all day — keeping your heart, brain and organs running. We use the Mifflin-St Jeor equation, the most accurate widely-used formula. It takes your weight, height, age and sex. Larger, younger and male bodies have higher BMRs because they carry more lean tissue.
Step 2 — Activity (TDEE)
Almost nobody lies in bed all day, so we multiply your BMR by an activity factor from 1.2 (sedentary) up to 1.9 (very active). The honest choice here matters most — people routinely overestimate how active they are, which inflates the target. If in doubt, pick one level lower.
Step 3 — Your goal
To lose fat, we subtract a calorie deficit (a Standard pace is about 500/day, roughly 0.45 kg or 1 lb per week). To build muscle, we add a modest surplus so you gain lean mass without excess fat. To maintain, your target is simply your TDEE.
Protein, carbs and fat
Calories tell you how much to eat; macros tell you what. We set protein from your body weight (more when cutting or building, to protect muscle), give fat a healthy share for hormones, and fill the rest with carbs for energy. The split updates with your goal.
Why tracking beats a one-time number
Formulas are a starting estimate — your real metabolism can run higher or lower. That's why this tool keeps a weight log: weigh in regularly, watch the trend line, and if it's not moving the way your goal expects after two or three weeks, nudge your calories by 100–150 and reassess. The progress tracker above does this comparison for you automatically.
Frequently asked questions
How many calories should I eat to lose weight?
Eat about 500 calories below your maintenance (TDEE) for steady fat loss of roughly 0.45 kg (1 lb) per week. Set your goal to "Lose fat" above and the calculator does the math for your body. Avoid dropping below about 1,200 (women) or 1,500 (men) calories a day without medical supervision.
Is the calorie number exact?
It's an accurate estimate, but every body is a little different. Use it as your starting point, then let the progress tracker fine-tune it: if your weight trend isn't matching your goal after 2–3 weeks, adjust by 100–150 calories.
Is my data stored anywhere?
No. Everything runs in your browser. Your weight log is saved only in this browser's local storage on your own device — it is never uploaded, and you can clear it any time.