The taxable value of a board fringe benefit is $2.00 per meal per person ($1.00 per person if under the age of 12). You reduce this by any amount the employee pays for the meal. Incidental refreshments such as morning and afternoon teas supplied as part of board are exempt from FBT.
Where you have an agreement in place with your employee which requires them to make a contribution towards their board meals and their accommodation, you may apportion that contribution on any reasonable basis.