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Scope 3

How to Calculate Grey Fleet Emissions

Step-by-Step Process

  1. 1

    Extract mileage from expense claims

  2. 2

    Classify by vehicle type if known

  3. 3

    Apply average petrol/diesel factors

  4. 4

    Calculate total emissions

  5. 5

    Consider promoting low-emission alternatives

Key Formulas

Miles × Fuel Factor = kg CO2ePetrol: 0.193 kg CO2e/mileDiesel: 0.168 kg CO2e/mile

Common Mistakes to Avoid

  • Using fuel cost instead of mileage
  • Not separating business from commuting mileage
  • Missing claims below threshold
  • Using outdated factors

Tools & Resources

  • Expense system
  • Mileage claims
  • DEFRA factors
  • Fuel card data

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ComplyCarbon handles all these calculations automatically with built-in UK Government conversion factors.

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