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TDEE & BMR Calculator

Calculate your Basal Metabolic Rate (BMR) and Total Daily Energy Expenditure (TDEE) to discover exactly how many calories your body burns every day.

TDEE, BMR & Macro Calculator

Calculate your Basal Metabolic Rate (BMR), Total Daily Energy Expenditure (TDEE), and macronutrient targets using the gold-standard Mifflin-St Jeor equation.

Unit System
Biological Sex

5'10" = 70 inches total

Activity Level
Goal
BMR = (10 × 81.6kg) + (6.25 × 177.8cm) − (5 × 30) + 5 = 1,783 kcal
TDEE = 1,783 × 1.55 = 2,764 kcal/day
Target (Cut (−500/day)) = 2,764 -500 = 2,264 kcal/day
BMR
1,783
calories at rest
TDEE
2,764
maintenance cal/day
Target (cut)
2,264
kcal/day
Daily Macros (30% protein / 35% fat / 35% carbs)
Protein
170g
680 kcal
4 cal/g — muscle preservation
Fats
88g
792 kcal
9 cal/g — hormones & brain
Carbs
198g
792 kcal
4 cal/g — primary energy
Protein 30%Fat 35%Carbs 35%

Practical Example (30yr Male, 180 lbs, 5'10", Moderate)

BMR: (10×81.65) + (6.25×177.8) − 150 + 5 = 1,783 kcal
TDEE: 1,783 × 1.55 = 2,763 kcal
Cut target: 2,763 − 500 = 2,263 kcal/day
Macros at cut: Protein 170g | Fat 88g | Carbs 198g → ~1 lb fat loss/week

💡 Field Notes

  • BMR is ~70% of all calories burned: Even without exercise, organs demand the majority of your energy. Diet has ~3× more impact on weight than exercise.
  • The 30/35/35 macro split is a baseline: Athletes cutting calories should push protein to 35–40% to prevent muscle loss. The 4 cal/g vs 9 cal/g density means fat hits your calorie cap much faster per gram.
  • Mifflin-St Jeor has ±10% error: Track actual weight for 2 weeks and adjust intake ±100–200 kcal based on real results — the formula is a starting hypothesis, not gospel.
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What is Metabolic Thermodynamics and Energy Balance?

Total Daily Energy Expenditure (TDEE) is the master metric of human weight management. It combines your Basal Metabolic Rate (the calories you burn at complete rest just to sustain organ function) with an activity multiplier that accounts for all physical movement. Understanding TDEE transforms weight management from guesswork into an engineering problem with a precise, calculable solution.

Mathematical Foundation

Mifflin-St Jeor Equation
BMR=(10×W)+(6.25×H)−(5×A)+S\text{BMR} = (10 \times W) + (6.25 \times H) - (5 \times A) + S
WW= Body weight in kilograms. Convert from lbs: kg = lbs × 0.453592.
HH= Height in centimeters. Convert from inches: cm = inches × 2.54.
AA= Age in years. BMR decreases approximately 1–2% per decade after age 30 due to declining lean mass.
SS= Gender constant: +5 for males, −161 for females. Reflects average differences in lean body mass and baseline hormonal metabolism.
Total Daily Energy Expenditure (TDEE)
TDEE=BMR×Activity Multiplier\text{TDEE} = \text{BMR} \times \text{Activity Multiplier}
1.21.2= Sedentary — office job, no planned exercise.
1.3751.375= Lightly Active — light exercise 1–3 days/week.
1.551.55= Moderately Active — moderate exercise 3–5 days/week.
1.7251.725= Very Active — hard training 6–7 days/week.
1.91.9= Extra Active — physically demanding job plus twice-daily training.

Laws & Principles

  • To lose one pound of fat per week, you must consume exactly 500 calories less than your TDEE every day. One pound of body fat stores approximately 3,500 kcal of energy. A consistent 500 kcal/day deficit creates a 3,500 kcal/week deficit, theoretically equivalent to 1 lb of fat oxidized. This relationship holds reasonably well in practice, though water retention and metabolism adaptation introduce ±20% variance.
  • Your BMR accounts for roughly 60–70% of all the calories you burn in a day, simply keeping your organs functioning. Even without any exercise or movement, your body demands the majority of its energy to maintain homeostasis — heart beating, lungs breathing, liver detoxifying, kidneys filtering, neurons firing.
  • The Mifflin-St Jeor equation carries a ±10% margin of error for individuals. Highly muscular people burn more than predicted (greater metabolically active lean tissue); the formula was validated on a mixed general population. Treat TDEE as a starting hypothesis, then track actual weight for 2–3 weeks and adjust by ±100–200 kcal.
  • Activity multipliers are notoriously over-estimated by users. Most sedentary office workers should use 1.2 even if they exercise 3 days/week — the 8–10 hours of sitting per day dictates the multiplier.

Step-by-Step Example Walkthrough

" A 30-year-old male weighing 180 lbs at 5'10" (70 total inches) with a moderately active lifestyle — lifts 4 days/week but has an office job. "

  1. Convert to metric: W_kg = 180 × 0.453592 = 81.65 kg. H_cm = 70 × 2.54 = 177.8 cm.
  2. Calculate BMR (male): (10 × 81.65) + (6.25 × 177.8) − (5 × 30) + 5 = 816.5 + 1111.25 − 150 + 5 = 1,782 calories.
  3. Apply activity multiplier (Moderately Active = 1.55): TDEE = 1,782 × 1.55 = 2,762 calories/day.
  4. Calculate targets: Fat Loss = 2,762 − 500 = 2,262 cal/day. Muscle Gain = 2,762 + 500 = 3,262 cal/day.
Final Result: His BMR is 1,782 calories at rest, but his TDEE is 2,762 calories/day. To lose 1 lb/week, he should eat 2,262 calories. To gain lean muscle at ~1 lb/week, he should eat 3,262 calories.

Quick Answer: How many calories do I burn a day?

Your Total Daily Energy Expenditure (TDEE) represents the total number of calories your body burns in 24 hours. It is calculated by determining your Basal Metabolic Rate (BMR) using the Mifflin-St Jeor equation, and scaling it by an activity multiplier (ranging from 1.2 to 1.9). This establishes your exact baseline for weight gain, loss, or maintenance.

Core Mechanics

The biological framework of weight management relies on thermodynamic energy balance governed by your resting metabolism and kinetic output.

BMR = (10 × W_kg) + (6.25 × H_cm) - (5 × Age) + S
TDEE = BMR × Activity Multiplier
Deficit Target = TDEE - 500 (For 1lb/week loss)

By isolating BMR before applying the kinetic activity load, the equation accounts for the 70% of energy required just to sustain autonomous organ function.

Real-World Scenarios

✅ Baseline Dieting

A 200 lb sedentary office worker computes a TDEE of 2,400 calories. By maintaining exactly 1,900 calories a day (a strict 500 deficit), they establish a sustainable 1 lb/week fat loss trajectory without crash dieting.

❌ The "Watch Trap"

A lifter sets their TDEE multiplier to 1.725 because they lift 6 days a week, inflating their TDEE to 3,200 calories. Because they sit at a desk the other 23 hours, their real TDEE is 2,700, resulting in unwanted fat gain on a "cut."

Activity Matrix Benchmarks

Multiplier Classification Clinical Description
1.2 Sedentary Desk job, zero intentional exercise. 90% of modern adults fall here.
1.375 Lightly Active Light exercise 1-3 days per week (e.g. 30 min walks).
1.55 Moderately Active Moderate exercise 3-5 days/week. Common for regular gym-goers.
1.725 Very Active Hard training 6-7 days/week or physically demanding labor job.
1.9 Extra Active Twice a day training (athletes) or extreme manual labor.

Pro Tips & Common Mistakes

Do This

  • ✓Select conservative multipliers. When in doubt, round your activity level down to prevent overestimating your caloric ceiling.
  • ✓Treat TDEE as a baseline hypothesis. Follow your calculated calories strictly for 14 days, measure your weight change, and dynamically adjust down or up by 10%.

Avoid This

  • ✗Don't double dip calories. If you calculate your TDEE at 'Moderately Active', do not eat back the calories your smartwatch claims you burned; they are already factored into the multiplier.
  • ✗Don't drop below your BMR. Eating below your Basal Metabolic Rate strips the body of the baseline energy required for organ and endocrine homeostasis, crashing your metabolism entirely.

Frequently Asked Questions

Why doesn't the TDEE calculator account for my smartwatch calories?

Activity multipliers (1.2 through 1.9) inherently include the oxidative output of your daily workouts. If you calculate an active TDEE and then also add in smartwatch calories, you are double-counting the exercise expenditure, which is the leading cause of failed diet phases.

Can my BMR be 'damaged' or slow down?

Metabolic adaptation is real but highly exaggerated. When you lose weight, your body physically requires less energy to move a lighter mass, and NEAT (Non-Exercise Activity Thermogenesis) subtly decreases. However, your actual BMR formula remains highly accurate for your new mass metrics.

Should I use my current weight or goal weight for the Mifflin-St Jeor equation?

Always trace the math to your current physical weight. To synthesize weight loss, you calculate the TDEE of your current mass, and then apply a fixed kinetic deficit (such as -500 calories). Using your goal weight immediately mathematically distorts the baseline caloric load required to function today.

How often should I recalculate my TDEE?

Recalibrate your BMR and TDEE every 10 pounds (4.5 kg) of weight shift. As an individual sheds macroscopic bodily weight, the caloric output required to sustain life naturally lowers, meaning plateaus will occur unless the caloric ceiling is systematically tracked downward.

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