E-Factor Calculator Formula

Understand the math behind the e-factor calculator. Each variable explained with a worked example.

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Formulas Used

E-Factor

e_factor = total_waste / product_mass

Process Mass Intensity (PMI)

process_mass_intensity = (total_waste + product_mass) / product_mass

Variables

VariableDescriptionDefault
total_wasteTotal Waste Mass(kg)25
product_massDesired Product Mass(kg)1

How It Works

E-Factor (Environmental Factor)

The E-factor is a green chemistry metric that quantifies the waste intensity of a chemical process.

Formula

E-factor = total waste (kg) / desired product (kg)

Typical values: bulk chemicals 1-5, fine chemicals 5-50, pharmaceuticals 25-100+. Lower is better. The related Process Mass Intensity (PMI) = (waste + product) / product = E-factor + 1.

Worked Example

A pharmaceutical synthesis produces 1 kg of product and 25 kg of waste.

total_waste = 25product_mass = 1
  1. 01E-factor = 25 / 1 = 25
  2. 02PMI = (25 + 1) / 1 = 26
  3. 03For every kg of product, 25 kg of waste is generated.

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