Calorie Calculator — Daily TDEE & Maintenance Calories

This free calorie calculator estimates the daily calories you burn — your Total Daily Energy Expenditure (TDEE) — and the intake needed to lose, maintain, or gain weight. It calculates your Basal Metabolic Rate using the Mifflin-St Jeor equation, the most accurate everyday BMR formula, then multiplies by an activity factor. A roughly 500-calorie daily deficit predicts about half a kilogram of fat loss per week. All results are estimates computed locally in your browser; track your real weight trend and adjust.

Try an example:
TDEE (maintain weight)
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Lose weight (−500 kcal)
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Gain weight (+500 kcal)
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✨ Pro Tips for Best Results

  • Activity Level: Be honest! Most people overestimate their activity. If you have a desk job, start with "Sedentary" even if you walk occasionally.
  • Protein Intake: When cutting calories, keep protein high (1.6g - 2.2g per kg of body weight) to prevent muscle loss.
  • Weekly Average: Don't obsess over daily numbers. Focus on your weekly average calorie intake for sustainable results.

What is the difference between BMR and TDEE?

Your BMR (Basal Metabolic Rate) is the number of calories your body needs to function at rest (breathing, circulating blood, cell production). Your TDEE (Total Daily Energy Expenditure) is your BMR plus the calories burned through physical movement and digestion.

To lose weight, you must eat fewer calories than your TDEE, but usually not fewer than your BMR. Eating below your BMR for long periods can lead to metabolic adaptation and extreme fatigue.

How are daily calorie needs calculated?

This calculator uses the Mifflin-St Jeor equation — the most validated formula for estimating Basal Metabolic Rate (BMR), the calories your body burns at complete rest. The equations are:

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

BMR is then multiplied by an activity factor to estimate Total Daily Energy Expenditure (TDEE): Sedentary ×1.2, Lightly active ×1.375, Moderately active ×1.55, Very active ×1.725, Extremely active ×1.9. For weight loss, subtract 500 kcal/day from TDEE for approximately 0.5 kg/week of fat loss. For weight gain, add 300–500 kcal. These are estimates — individual metabolism varies, and tracking actual weight change over 2–3 weeks gives the most accurate personal baseline.

Related tools

Macro calculator → BMI calculator → Water intake →

Related tools & guides

BMI calculator → Macro calculator → Water intake → Understanding TDEE →

Related Guide: Learn more about TDEE and metabolism

From BMR to your daily target

This tool uses the Mifflin-St Jeor equation, the most accurate everyday formula for Basal Metabolic Rate — the energy your body burns at complete rest. For men: BMR = 10·kg + 6.25·cm − 5·age + 5; for women the last term is −161. Multiplying BMR by an activity factor (1.2 sedentary up to 1.9 for hard daily training) gives your Total Daily Energy Expenditure, the calories that keep your weight stable.

Deficits and surpluses

Roughly 7,700 kcal equals one kilogram of body fat. A 500 kcal daily deficit therefore predicts about 0.45 kg of loss per week — a sustainable pace that preserves muscle. Aggressive deficits beyond ~25% of TDEE risk muscle loss, fatigue and metabolic slowdown. To gain lean mass, a modest 250–500 kcal surplus paired with resistance training minimises fat gain.

Why estimates drift

TDEE is a prediction, not a measurement; metabolism, NEAT (fidgeting and daily movement) and food-label inaccuracy all vary. Track your real weight trend over 2–3 weeks and adjust intake by 100–200 kcal if the scale isn't moving as expected.

⚠️ Common Mistakes to Avoid

Frequently asked questions

What is a calorie calculator and what does it estimate?

A calorie calculator estimates how many calories your body burns each day — your Total Daily Energy Expenditure (TDEE) — and the intake needed to lose, maintain, or gain weight at a chosen rate.

How does the calorie calculator work?

It first estimates your Basal Metabolic Rate (BMR) using the Mifflin-St Jeor equation, then multiplies it by an activity factor from 1.2 (sedentary) to 1.9 (very active) to give your maintenance calories, or TDEE.

How many calories should I eat to lose weight?

Roughly 7,700 calories equal one kilogram of body fat, so a 500-calorie daily deficit predicts about 0.45 kg of loss per week — a sustainable pace that preserves muscle. Avoid deficits beyond about 25% of your TDEE.

How accurate are calorie calculators?

They are good estimates, not exact measurements. The Mifflin-St Jeor equation is accurate to within about 10% for most people, but metabolism, daily movement (NEAT), and food-label errors all introduce variance.

What are the limitations of calorie estimates?

Predicted TDEE assumes average metabolism and accurate activity self-reporting, both of which vary. The reliable approach is to track your real weight trend over two to three weeks and adjust your intake by 100–200 calories if it is not moving as expected.

What is the difference between BMR and TDEE?

BMR is the energy your body burns at complete rest just to stay alive. TDEE is your total daily burn including movement, digestion, and exercise — BMR multiplied by an activity factor. TDEE is the number that governs weight change.

Should I eat in a surplus to gain muscle?

Yes — a modest surplus of about 250–500 calories above TDEE, paired with resistance training, supports lean muscle gain while minimising fat gain. Larger surpluses mostly add fat.

Related guides

What is TDEE? → Understanding TDEE →
Reviewed by the ToolsmithPro editorial team · Last updated June 2026. Every calculation and conversion runs entirely in your browser — your inputs are never uploaded, stored or shared. Formulas and methodology are documented on our about page; spot an error? tell us and we'll fix it.