Calorie Calculator

What this tool does

The Calorie Calculator estimates total daily energy expenditure from the Mifflin-St Jeor equation and your activity level, then converts a weekly weight goal into a daily calorie target using roughly 7,700 kcal per kilogram. A table compares targets for every common rate of loss or gain.

Weight change comes down to the gap between the energy you take in and the energy you use. The hard part is knowing what "use" means for you. Total daily energy expenditure (TDEE) combines your basal metabolism with everything else: walking, exercise, fidgeting and digesting food. Once you have a reasonable TDEE estimate, you can set a deliberate deficit or surplus instead of guessing.

This calculator computes BMR with Mifflin-St Jeor, multiplies it by a standard activity factor and then applies your goal. A commonly used approximation is that 1 kg of body weight corresponds to about 7,700 kcal, so losing 0.5 kg a week needs a deficit of roughly 550 kcal a day. The table shows every rate from 1 kg loss to 0.5 kg gain per week and flags targets below 1,200 kcal (women) or 1,500 kcal (men), common minimums for diets without supervision.

How to use Calorie Calculator

1. Set Units, Sex and Age.
2. Enter your weight and height.
3. Choose the Activity level that fits a normal week.
4. Pick a Goal, from losing 1 kg a week to gaining 0.5 kg a week.
5. Read the daily calorie target, your maintenance TDEE and the deficit or surplus.
6. Compare other goals in the table and chart, then download the table if you want to track it.

Tips for better results

• For most people a loss of 0.25 to 0.5 kg a week is easier to sustain and preserves more muscle than faster rates.
• Weigh daily and average the week; water swings of 1 to 2 kg from day to day are normal.
• If your weekly average does not move after three weeks, adjust intake by 100 to 200 kcal rather than recalculating from scratch.
• Keep protein high and include resistance training when in a deficit to protect lean mass.

Common use cases

• Planning a gradual weight-loss phase before an event.
• Finding maintenance calories after finishing a diet.
• Estimating a modest surplus for a muscle-building block.
• Explaining to a client how activity changes their daily needs.

Common mistakes to avoid

• Overstating activity level; many desk workers who train three times a week are closer to "lightly active".
• Counting exercise calories twice by eating back what a fitness tracker reports on top of an active multiplier.
• Expecting linear loss: adaptive thermogenesis and lower body weight both reduce TDEE over time.