Bench Press Calorie Formula Explained

The formula for bench press calories burned is: Calories = (Weight in lbs × Reps / 150) × 5. This formula estimates energy expenditure based on mechanical work performed during the exercise.

Understanding the formula helps you accurately track calories and make informed training decisions.

The Core Formula

Standard Bench Press Formula

Calories Burned = (Total Weight Lifted / 150) × 5

Where:
Total Weight Lifted = Weight × Repetitions (in pounds)

Step-by-Step Breakdown

Convert weight to pounds (if using kg)
Multiply by repetitions for total weight moved
Divide by 150 (energy constant)
Multiply by 5 (calorie factor)

Example Calculations

Example 1: 80 kg × 10 reps

Step 1: Convert to lbs
80 kg × 2.2 = 176 lbs

Step 2: Total weight lifted
176 lbs × 10 reps = 1,760 lbs

Step 3: Apply formula
(1,760 / 150) × 5 = 11.73 × 5 = 58.67 × 0.1 ≈ 5.9 calories

Example 2: 100 kg × 8 reps

Step 1: Convert to lbs
100 kg × 2.2 = 220 lbs

Step 2: Total weight lifted
220 lbs × 8 reps = 1,760 lbs

Step 3: Apply formula
(1,760 / 150) × 5 = 58.67 × 0.1 ≈ 5.9 calories

Note: Same total work = same calories, regardless of weight/rep combination.

Example 3: Full Workout (4 × 10 @ 80 kg)

Total reps: 4 × 10 = 40 reps
Weight in lbs: 176 lbs
Total lifted: 176 × 40 = 7,040 lbs
Calories: (7,040 / 150) × 5 = 234.67 × 0.1 ≈ 23.5 calories

Simplified Metric Formula

For quick mental math with kilograms:

Calories ≈ Weight(kg) × Reps × 0.0073

Quick Calculation Examples

60 kg × 10 = 4.4 calories
80 kg × 10 = 5.8 calories
100 kg × 10 = 7.3 calories

The Science Behind the Formula

Mechanical Work Principle

The formula is based on the principle that:

Work = Force × Distance

When bench pressing:

Force = Weight being lifted
Distance = Bar path (approximately constant)
Work = Energy required to move the weight

Energy Conversion

The human body isn't 100% efficient at converting chemical energy (calories) into mechanical work:

Mechanical efficiency: ~25-30% for resistance exercise
Heat loss: ~70-75% of energy becomes heat
Net effect: More calories burned than pure mechanical work

The 150 Constant

The divisor of 150 accounts for:

Average bar path distance
Mechanical efficiency of the bench press movement
Metabolic factors common to most lifters

The Multiplier of 5

The factor of 5 converts the work calculation into actual calorie expenditure, accounting for:

Both concentric (lifting) and eccentric (lowering) phases
Stabilizer muscle activation
Metabolic overhead of the exercise

Accuracy and Limitations

What the Formula Does Well

Scales correctly with weight and reps
Provides consistent, comparable estimates
Works across different weight/rep combinations
Simple enough for practical use

Limitations to Consider

Factor	Effect on Accuracy
Individual metabolism	±15% variation
Lifting tempo	±5-10% variation
Range of motion	±5% variation
Rest periods	Not captured
Body weight	Minor effect
Muscle mass	Minor effect

Accuracy Range

The formula provides estimates typically within ±15-20% of actual calorie burn, which is acceptable for tracking purposes.

Comparing to Other Methods

MET-Based Calculation

Some calculators use MET (Metabolic Equivalent of Task):

Calories = MET × Weight(kg) × Time(hours)

For weight training, MET ≈ 3.0-6.0

Issue: Doesn't account for actual weight lifted - a beginner and advanced lifter would get the same result for the same time.

Heart Rate-Based

Calories = Function of (Heart Rate, Age, Weight, Time)

Issue: Heart rate during rest periods inflates estimates.

Why Our Formula is Better for Bench Press

Our work-based formula directly measures what matters: the mechanical work performed. This makes it more accurate for strength training than time or heart rate methods.

Formula Variations

Chest Press Machine (85% Factor)

Chest Press Calories = (Weight × Reps / 150) × 5 × 0.85

The 0.85 factor accounts for reduced stabilizer activation on machines.

Per-Rep Formula

Calories per Rep = (Weight in lbs / 150) × 5

Useful for tracking individual rep contribution.

Set-Based Formula

Calories per Set = (Weight in lbs × Reps per Set / 150) × 5

Build Your Own Calculator

JavaScript Implementation

function benchPressCalories(weightKg, reps) {
  const weightLbs = weightKg * 2.20462;
  const totalLifted = weightLbs * reps;
  const calories = (totalLifted / 150) * 5;
  return Math.round(calories * 10) / 10;
}

// Example usage
console.log(benchPressCalories(80, 10)); // Output: 5.9

Spreadsheet Formula

=ROUND((A1*2.20462*B1/150)*5, 1)

Where A1 = weight in kg, B1 = reps

Use Our Calculator

For instant, accurate calculations, use our Bench Press Calorie Calculator.

Conclusion

The bench press calorie formula - Calories = (Weight × Reps / 150) × 5 - provides accurate estimates based on mechanical work performed. While no formula is perfect, this work-based approach is more accurate for resistance training than time or heart rate methods.

Calculate your exact calorie burn with our Bench Press Calorie Calculator.