Calorie Calculator to Lose Weight
Weight loss ultimately comes down to one principle: eat fewer calories than you burn. But how many fewer? Too large a deficit causes muscle loss, fatigue, and metabolic slowdown; too small and progress is frustratingly slow. This calorie calculator for weight loss gives you a precise daily calorie target based on your body stats and activity level, then shows three deficit tiers — mild (0.25 kg/week), moderate (0.5 kg/week), and aggressive (0.75 kg/week) — so you can choose the pace that fits your lifestyle and timeline. We use the Mifflin-St Jeor equation, which is endorsed by the Academy of Nutrition and Dietetics as the most accurate for estimating resting metabolic rate.
Your Details
Example Use Cases
A 75 kg, 35-year-old moderately active woman needs ~2,200 kcal/day to maintain weight. For moderate fat loss (0.5 kg/week), she'd eat ~1,700 kcal/day.
A 90 kg, 28-year-old lightly active man needs ~2,500 kcal/day. For aggressive fat loss (0.75 kg/week), he'd eat ~1,925 kcal/day — still above the 1,500 kcal male minimum.
How to Interpret Your Results
Always check that your weight-loss calorie target doesn't fall below 1,200 kcal/day (women) or 1,500 kcal/day (men). Eating below these levels without medical supervision is associated with nutrient deficiencies and metabolic adaptation.
Frequently Asked Questions
Methodology & Limitations
Formulas Used
Uses the **Mifflin-St Jeor** equation to estimate BMR, then multiplies by a physical activity level factor. Weight-loss targets use a 500 kcal/day deficit (~0.45 kg/week); weight-gain targets use a 300 kcal/day surplus.
Page-Specific Notes
Three deficit tiers: mild (−250 kcal), moderate (−500 kcal), aggressive (−750 kcal). The calculator flags if any tier pushes intake below safe minimums.
Limitations
Individual metabolism varies. These estimates should be treated as a starting point. Track your weight for 2–4 weeks and adjust intake by 100–200 kcal as needed.
Sources & Citations
- Mifflin MD, St Jeor ST, et al. Am J Clin Nutr. 1990;51(2):241-247.
- Hall KD, et al. Quantification of the effect of energy imbalance on bodyweight. Lancet. 2011;378(9793):826-837.
Medical Disclaimer: This calculator provides estimates based on published formulas and is not a substitute for professional medical advice. Always consult a qualified healthcare provider before making changes to your diet or exercise routine.
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