Weight Loss Calculator

If % is provided, it will override target weight.
Selected pace: Moderate (0.5 kg/week)  — drag to adjust pace (0.25 to 1 kg/week).

How this weight loss calculator works — and how to use the results

This tool combines a standard metabolic estimate with your activity level and the weight-loss pace you choose to produce a practical daily calorie target and an estimated timeline to reach your goal. The calculation begins by estimating your basal metabolic rate (BMR), which is the number of calories your body needs at rest to support essential functions. We use the commonly applied Mifflin–St Jeor formula:

Mifflin–St Jeor: Male: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5
Female: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161

After BMR we apply an activity multiplier to estimate total daily energy expenditure (TDEE). Typical multipliers represent broad activity bands: sedentary (little activity), lightly active, moderately active, and very active. TDEE = BMR × activity factor.

To create a calorie target for weight loss we calculate the daily calorie deficit implied by the pace you choose. A kilogram of body weight is commonly estimated as approximately 7,700 calories. So if you aim to lose 0.5 kg per week, the weekly deficit is about 3,850 kcal, which equals roughly 550 kcal/day. Daily target calories = TDEE − (weeklyDeficit / 7).

Time to goal equals the weight difference divided by your chosen weekly pace (weeks = (current − target) / kg_per_week). The displayed timeline shows weekly milestones and an expected goal date, assuming consistent daily intake and activity.

Practical notes and accuracy

These estimates are a planning tool. Real-world weight change is influenced by water shifts, body composition changes, hormonal factors, and adherence. Small short-term fluctuations are normal; long-term trends matter most. Tracking progress and adjusting intake using measured weight over several weeks will refine estimates.

Safety and recommended minimum calorie levels

For safety, calorie targets below commonly accepted minimums (for example ~1,200 kcal/day for many women and ~1,500 kcal/day for many men) are flagged. Very low calorie diets should be supervised by a qualified professional. If your calculated target falls below these thresholds, consider a slower pace or medical guidance.

Smart coaching and lifestyle tips

A moderate deficit (e.g., 0.25–0.5 kg/week) is easier to sustain and tends to preserve lean mass better than aggressive approaches. Pairing a modest calorie reduction with protein-rich meals and resistance training helps protect muscle. Sedentary users can gain benefit from daily walking and small movement breaks; active users should prioritize recovery, sleep and adequate protein.

Use this tool as a starting plan. Monitor progress, adjust based on real measurements, and consult professionals for personalized medical or nutrition guidance.