Total cost of occupancy is everything a building actually costs per year: rent, business rates or property taxes, service charges, utilities, insurance, cleaning, security, maintenance, fit-out amortisation and facilities staff. Rent alone typically represents only half to two thirds of the true figure, which is why comparing buildings on headline rent misleads.
Finance teams divide total cost of occupancy by headcount or by desks to make sites comparable, then set it against utilisation to see what occupied capacity really costs.