Calorie Calculator
Estimate your daily calorie needs to maintain, lose or gain weight.
This tool runs entirely in your browser. Your files are never uploaded to a server.
These are estimates from a standard formula, not a measured metabolic rate — actual needs vary by individual. This is not medical or nutritional advice; consult a professional before making major dietary changes.
1699
BMR (kcal/day)
2633
Maintenance (kcal/day)
2133
Lose weight (kcal/day)
3133
Gain weight (kcal/day)
What this calculator does
Estimates Basal Metabolic Rate (BMR) using the Mifflin-St Jeor equation, scales it by an activity multiplier for Total Daily Energy Expenditure (TDEE), and shows calorie targets for maintaining, losing or gaining weight.
How to use it
Select your sex, then enter age, height and weight in metric units, and choose the activity level that best matches your typical week. Results update immediately as you change any value.
Worked example
For a 30-year-old male, 175 cm tall, weighing 75 kg, with moderate exercise (activity factor 1.55), BMR is about 1,698.75 kcal/day, maintenance (TDEE) is about 2,633.06 kcal/day, the suggested target to lose weight is about 2,133.06 kcal/day, and to gain weight about 3,133.06 kcal/day. Automated tests verify these figures.
Formula
Mifflin-St Jeor BMR: men = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5; women = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161. TDEE = BMR × activity multiplier, ranging from 1.2 (sedentary) to 1.9 (athlete, training twice a day). The lose/gain figures apply a flat 500 kcal/day deficit or surplus to TDEE.
Why 500 kcal/day
A 500 kcal/day deficit or surplus is a commonly cited starting point because roughly 3,500 kcal is often associated with about one pound (0.45 kg) of body weight change, making 500 kcal/day a rough weekly pace of about 0.5 kg. That 3,500-kcal figure is itself a long-standing approximation, not a precise physiological constant, so actual results vary by individual.
Limitations
This estimates energy needs from a population-average formula, not a measured metabolic rate — actual BMR varies with body composition, genetics, hormonal status and health conditions that this calculator cannot see. The activity levels are broad categories, not a precise accounting of your actual daily movement.
Scope, sources and privacy
This is an educational estimate, not medical or nutritional advice, and not a substitute for guidance from a registered dietitian or physician, especially with a medical condition or during pregnancy. The Mifflin-St Jeor equation (Mifflin et al., 1990, American Journal of Clinical Nutrition) and activity-factor conventions were checked against that literature and standard dietetics references. Reviewed September 2026. Calculation runs locally in your browser; Quiklio does not upload the entered values.
Frequently Asked Questions
- What formula does this use?
- It uses the Mifflin-St Jeor equation to estimate Basal Metabolic Rate (BMR), then multiplies by an activity factor for total daily energy expenditure (TDEE).
- How much should I cut calories to lose weight?
- A common approach is a 500 kcal/day deficit, roughly targeting about 0.5 kg of weight loss per week — consult a professional for personalized advice.
- Is this medical advice?
- No, these are general estimates for informational purposes only, not a substitute for professional medical or nutritional advice.