What This Calculator Estimates
Daily calorie needs depend on your Basal Metabolic Rate (BMR) plus your activity level, typically calculated by multiplying BMR by an activity multiplier ranging from sedentary to very active, giving an estimate of Total Daily Energy Expenditure (TDEE) — the calories needed to maintain your current weight. From there, calorie needs for weight loss or gain are typically calculated as a deficit or surplus from this maintenance baseline.
How to Use This Calculator
- Enter age, sex, height, weight, and activity level.
- Use current measurements for a more relevant estimate.
- Click Estimate Calories to view the result.
- Review the maintenance estimate and related guidance.
- Recalculate when your routine or body measurements change.
Formula / Method Used
This uses the Mifflin-St Jeor equation, widely regarded as the most accurate standard formula for resting metabolic rate: for men, BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5. For women, BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161. BMR is then multiplied by an activity factor (1.2 sedentary to 1.9 very active) to estimate total daily calorie needs.
Worked Example
A 30-year-old woman, 65kg, 165cm, moderately active (factor 1.55): BMR = 10(65) + 6.25(165) − 5(30) − 161 = 650 + 1031.25 − 150 − 161 = 1,370.25. Daily calorie needs ≈ 1,370 × 1.55 ≈ 2,124 calories.
Official Sources
Related Calculators
Tips for a More Accurate Estimate
- Choose an activity multiplier that reflects your typical week, not just your best days.
- Remember this gives a maintenance estimate — weight loss/gain requires a deficit or surplus from that baseline.
- Recalculate as your weight or activity level changes significantly over time.
- Pair calorie needs with adequate protein intake if your goal includes muscle maintenance or growth.
- Treat this as a starting estimate to adjust based on real-world results, not a fixed prescription.
Frequently Asked Questions
How is daily calorie need calculated?
It's typically your BMR multiplied by an activity factor reflecting how active you are, resulting in an estimated maintenance calorie level (TDEE).
What activity multiplier should I use?
Common ranges go from sedentary to very active — choose the level that best reflects your typical week, not just your best or worst days.
How many calories should I eat to lose weight?
Weight loss typically requires eating below your maintenance calorie level, though the appropriate deficit depends on your goals and individual factors.
Does this calculator account for specific dietary goals like muscle gain?
No, this estimates general calorie needs. Specific goals involve additional considerations like protein intake and training program.
How often should I recalculate my calorie needs?
Recalculate whenever your weight, activity level, or goals change significantly.
This calculator provides informational health estimates only and is not medical advice. Individual calorie needs can vary.
Last updated: May 11, 2026