Calories Calculator
Estimate daily calorie needs (BMR & TDEE) based on age, sex, weight, height, and activity level.
Overview
This calculator estimates daily calorie requirements using the Mifflin-St Jeor equation. It first estimates BMR (resting energy use), then applies an activity multiplier to estimate maintenance calories (TDEE). It also provides starter targets for fat loss and muscle gain planning.
How the calculation works
Calculates BMR using Mifflin-St Jeor and multiplies by activity factor to estimate maintenance calories (TDEE).
Edge cases and validation notes
- Unrealistic age/height/weight values
- Very high athletic loads
- Medical conditions affecting metabolism
Worked examples
- Male, 30y, 75kg, 175cm, moderate -> BMR ~1674, maintenance ~2594 kcal/day
Common use cases
- Set a maintenance calorie baseline before changing diet.
- Estimate a starting calorie deficit for fat loss.
- Estimate a controlled calorie surplus for lean gain.
- Compare calorie needs across activity levels.
Examples and notes
- Male, 30y, 75kg, 175cm, moderate activity -> maintenance around 2,500-2,700 kcal/day.
- Fat-loss target is typically maintenance minus 300-500 kcal/day.
- Muscle-gain target is often maintenance plus 200-300 kcal/day.
Important note
These values are estimates, not medical prescriptions. Track weekly body-weight trend and adjust calories based on actual response.
Frequently Asked Questions
What is BMR?
BMR (Basal Metabolic Rate) is the calories your body needs at complete rest to maintain vital functions.
What is TDEE?
TDEE (Total Daily Energy Expenditure) is your estimated maintenance calories after applying your activity level to BMR.
How should I use this for weight loss or gain?
A common starting point is a 300-500 kcal/day deficit for fat loss or a 200-300 kcal/day surplus for lean gain, then adjust based on progress.
Is this a medical prescription?
No. These are estimation formulas. Medical conditions, medications, and body composition can change actual requirements.