Calculating the total cost of business travel is not as clear cut as just taking the price of the journey into consideration.
There are other variables that need to be taken into deliberation when measuring the total cost such as loss in productivity through jet lag or illnesses a traveller might have picked up and loss of time caused by travelling or delays. These are grouped under the term traveller friction.
An easy way to calculate the total cost of business travel is through the equation coined by Scott Gillespie:
Total cost of travel = trip cost (£) + traveller friction