We have not surveyed staff. Can I estimate Category 7 from national commuting averages, the way the Greenhouse Gas Protocol's average-data method does?
Yes. The average-data method multiplies number of employees, share using each mode, one-way distance, two for the return trip, working days a year and a factor per mode, then adds the modes. For a company with over 10,000 employees, the Greenhouse Gas (GHG) Protocol's example uses 10,000 and 235 days and gives 6,697,500 kilograms.
What the method needs
The guide says averages may come from national transport departments, ministries or agencies, national statistics and industry associations, and that the method needs several simplifying assumptions which add uncertainty.
- Number of employees.
- The average distance an average employee travels each day.
- The average split of transport modes.
- The average number of working days a year.
- Factors for each mode, usually per passenger-kilometre.
Which days count
The guide says to multiply the one-way distance by two for the daily return trip and by the average days worked in the year, excluding weekends and days spent on business travel, vacation or working from home. A company with long shutdowns will have fewer days than 235 (our reading).
When to move to the survey method
The guide's order is fuel-based if you have fuel data, distance-based if you have distance and mode from employees, and average-data only when company data are unavailable. It says companies should survey employees annually for the distance-based method. Use the average as a first estimate and replace it with survey answers when you can.
A note for Indian firms
The guide's example uses United Kingdom government statistics and gives no Indian averages. For India, take working days from your own attendance records and a short count of how staff travel, and label the result an estimate (our reading).
The guide's example: 10,000 employees, 235 working days
- Rail, 50 percent, 10 kilometres one way, factor 0.1: 10,000 x 50% x 10 x 2 x 235 x 0.1 = 2,350,000 kilograms of carbon dioxide equivalent (CO2e)
- Car, 30 percent, 15 kilometres, factor 0.2: 10,000 x 30% x 15 x 2 x 235 x 0.2 = 4,230,000 kilograms CO2e
- Foot, 15 percent, 1 kilometre, factor 0: 0 kilograms CO2e
- Bus, 5 percent, 5 kilometres, factor 0.1: 10,000 x 5% x 5 x 2 x 235 x 0.1 = 117,500 kilograms CO2e
- Total: 2,350,000 + 4,230,000 + 0 + 117,500 = 6,697,500 kilograms CO2e
- Car is 30 percent of commutes but 4,230,000 of 6,697,500, about 63 percent of emissions
The guide says its activity data and factors are examples, and that employees in it do not share rides. Factors are per vehicle-kilometre or passenger-kilometre. Do not reuse the numbers.
What Senseible does here
Senseible reads fuel invoices and electricity bills into monthly records, which covers your own Scope 1 and 2. It does not collect commuting data, so averages and survey answers come from you.
- Employee commuting survey for a factory
- Commuting estimate for a small company
- Low survey response: what to do
- Work from home in Category 7
- Free calculators
Last reviewed 2026-11-05. Arithmetic multiplies out to the guide's printed 6,697,500.