Basal Metabolic Rate is the number of calories your body burns at complete rest to sustain basic functions including breathing, circulation, cell repair, and temperature regulation. It represents the minimum energy your body needs just to stay alive and is typically the largest single component of your total daily energy expenditure, often accounting for 60 to 70 percent of total calorie burn.

Which BMR formula is most accurate?

Mifflin-St Jeor is the most widely validated formula for general adult populations and is commonly recommended by dietitians for planning. Katch-McArdle tends to fit better for people who know their body fat percentage because it calculates from lean mass directly rather than total body weight, making it more precise for lean or heavily muscled individuals where weight alone is a poor predictor.

Why is my TDEE an estimate?

Activity multipliers are averages drawn from population studies and cannot capture your individual physiology, workout intensity, or non-exercise movement patterns. A desk job with three weekly gym sessions may sit between two different activity labels. Track your weight for two to four weeks at a fixed calorie intake and adjust by 100 to 200 kcal up or down until your weight trends match your goal.

How do lose-weight calorie targets map to pounds per week?

A 500 kcal per day deficit below your TDEE is the commonly cited target for losing roughly one pound per week based on the 3,500 calorie per pound estimate. A 250 kcal per day deficit is associated with approximately half a pound per week. Actual results vary with water retention, sleep quality, training volume, and how accurately you track intake.

Should I use Harris-Benedict or Mifflin-St Jeor?

Both formulas are shown so you can see the range rather than rely on a single number. Most coaches and registered dietitians default to Mifflin-St Jeor because it has been validated more recently and tends to be more accurate for modern sedentary and moderately active adults. Use the result that aligns with your scale trend over several weeks rather than the highest figure.

TDEE Calculator

Calculate your Total Daily Energy Expenditure based on three BMR formulas, your activity level, and your goal. BMR is computed internally as the baseline your TDEE builds on.

Want just your BMR without an activity level? Use our BMR Calculator.

SexAge (years)

Unit system

Height (cm)Weight (kg)

Activity levelGoal

Body fat % (optional, for Katch-McArdle)

TDEE (Mifflin-St Jeor)

2,711 kcal

Activity: Moderately active (3–5 days/week)

Goal calories (Maintain)

2,611–2,811 kcal/day

-0.2 to +0.2 lb/week

BMR by equation

Mifflin-St Jeor

1,749 kcal

TDEE: 2,711 kcal

Harris-Benedict (revised)

1,830 kcal

TDEE: 2,836 kcal

Katch-McArdle

Enter body fat % to show lean-mass BMR.

TDEE by activity (MSJ BMR)

Level	Multiplier	TDEE
Sedentary	×1.2	2,099 kcal
Lightly active	×1.375	2,405 kcal
Moderately active	×1.55	2,711 kcal
Very active	×1.725	3,017 kcal
Extra active	×1.9	3,323 kcal

Directional macros (goal midpoint)

Protein 141 g
Carbs 368 g
Fat 75 g

Directional split at goal midpoint using 0.8 g protein per lb body weight (add body fat % for lean-mass protein).

BMR equations are estimates. Individual metabolism often varies by about 15–20%. Track weight for 2–4 weeks and adjust calories by 100–200 kcal if results drift. Not medical advice.

How this tool works

Basal metabolic rate (BMR) is the calories your body burns at complete rest. The tool computes it with three formulas side by side. Mifflin-St Jeor (most commonly validated for general adults): BMR = (10 × weight_kg) + (6.25 × height_cm) − (5 × age) + 5 (men) or −161 (women). Revised Harris-Benedict: uses slightly different constants derived from a 2001 recalculation. Katch-McArdle: BMR = 370 + (21.6 × lean mass kg), which requires body-fat percentage as input and is more accurate for athletes because it ignores fat mass. Each BMR is then multiplied by an activity factor (sedentary 1.2, lightly active 1.375, moderately active 1.55, very active 1.725, extra active 1.9) to produce TDEE. Goal calorie bands apply a standard deficit or surplus: roughly −500 kcal/day for weight loss at approximately 0.45 kg/week. Key assumption: activity multipliers are population averages; self-reported activity level is the largest source of error. Edge case: rapid weight change, illness, or hormonal conditions can shift actual TDEE well outside formula predictions.

Worked example

A 30-year-old man at 80 kg and 175 cm with moderate activity often shows about 1,749 kcal BMR (Mifflin-St Jeor) and about 2,711 kcal TDEE. A maintenance band might sit near 2,600–2,800 kcal/day. With 15% body fat, Katch-McArdle adds a lean-mass-based BMR you can compare beside the other formulas.

Frequently asked questions

What is BMR?
Basal Metabolic Rate is the number of calories your body burns at complete rest to sustain basic functions including breathing, circulation, cell repair, and temperature regulation. It represents the minimum energy your body needs just to stay alive and is typically the largest single component of your total daily energy expenditure, often accounting for 60 to 70 percent of total calorie burn.
Which BMR formula is most accurate?
Mifflin-St Jeor is the most widely validated formula for general adult populations and is commonly recommended by dietitians for planning. Katch-McArdle tends to fit better for people who know their body fat percentage because it calculates from lean mass directly rather than total body weight, making it more precise for lean or heavily muscled individuals where weight alone is a poor predictor.
Why is my TDEE an estimate?
Activity multipliers are averages drawn from population studies and cannot capture your individual physiology, workout intensity, or non-exercise movement patterns. A desk job with three weekly gym sessions may sit between two different activity labels. Track your weight for two to four weeks at a fixed calorie intake and adjust by 100 to 200 kcal up or down until your weight trends match your goal.
How do lose-weight calorie targets map to pounds per week?
A 500 kcal per day deficit below your TDEE is the commonly cited target for losing roughly one pound per week based on the 3,500 calorie per pound estimate. A 250 kcal per day deficit is associated with approximately half a pound per week. Actual results vary with water retention, sleep quality, training volume, and how accurately you track intake.
Should I use Harris-Benedict or Mifflin-St Jeor?
Both formulas are shown so you can see the range rather than rely on a single number. Most coaches and registered dietitians default to Mifflin-St Jeor because it has been validated more recently and tends to be more accurate for modern sedentary and moderately active adults. Use the result that aligns with your scale trend over several weeks rather than the highest figure.