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How to Calculate Your Daily Calorie Needs:
BMR, TDEE & Weight Goals

Jun 7, 2026 · Related: Calorie Calculator

Whether you want to lose weight, build muscle, or just maintain your current physique, it all starts with one number: how many calories your body actually needs each day. This guide walks through the science-backed formulas used by nutritionists worldwide.

Step 1: Calculate Your BMR (Basal Metabolic Rate)

Your BMR is the number of calories your body burns at complete rest — just to keep your heart beating, lungs breathing, and cells functioning. It accounts for roughly 60–70% of your total daily calorie burn.

The most accurate widely-used formula is the Mifflin-St Jeor equation (1990):

Men: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5
Women: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161

Example (30-year-old male, 175cm, 70kg):
BMR = 10(70) + 6.25(175) − 5(30) + 5 = 1,649 kcal/day

Step 2: Multiply by Your Activity Factor (TDEE)

Multiply your BMR by an activity multiplier to get your Total Daily Energy Expenditure (TDEE) — the calories you actually burn on a typical day.

Activity Level	Description	Multiplier
Sedentary	Desk job, little or no exercise	× 1.2
Lightly active	Light exercise 1–3 days/week	× 1.375
Moderately active	Moderate exercise 3–5 days/week	× 1.55
Very active	Hard exercise 6–7 days/week	× 1.725
Extra active	Physical job + daily intense exercise	× 1.9

Step 3: Adjust for Your Goal

A deficit or surplus of ~500 kcal/day leads to roughly 0.5 kg (1 lb) of weight change per week.

Goal	Daily Target	Expected Result
Lose weight	TDEE − 500 kcal	~0.5 kg (1 lb) loss/week
Maintain weight	TDEE	No change
Build muscle (lean bulk)	TDEE + 300 kcal	Slow muscle gain, minimal fat
Bulk aggressively	TDEE + 500 kcal	Faster muscle gain, some fat

Factors That Affect Your BMR

Factor	Effect
Muscle mass	More muscle = higher BMR (muscle burns more at rest than fat)
Age	BMR drops ~2–3% per decade after 30
Sex	Men typically have higher BMR due to greater muscle mass
Body temperature	Fever raises BMR ~7% per 1°C rise
Long-term dieting	Extended calorie restriction can lower BMR (metabolic adaptation)

Common Mistakes to Avoid

Calorie calculations give an estimate, not an exact number. Individual variation of ±200 kcal/day is normal. Here are the most common mistakes:

Mistake	Why It Matters
Overestimating activity level	Most sedentary people are truly sedentary; choosing "moderate" overstates TDEE by 200–300 kcal
Eating below BMR	Going below BMR triggers muscle loss, fatigue, and metabolic slowdown
Not tracking for 2–3 weeks	Formulas are starting points; track weight weekly and adjust as needed
Ignoring liquid calories	Coffee drinks, juices, and alcohol add up quickly without feeling filling

⚠️ Minimum safe intake: Generally, women should not go below 1,200 kcal/day and men below 1,500 kcal/day without medical supervision, regardless of TDEE.

💡 Pro tip: Instead of cutting big, add one 30-minute walk per day. That burns about 150–200 kcal, raising your TDEE without triggering hunger or metabolic adaptation.

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How to Calculate Your Daily Calorie Needs:BMR, TDEE & Weight Goals