Property is often constructed by an entity over an extended period of time and the entity may incur interest cost on funds borrowed to finance the construction. IAS 23 provides that such cost must be added to the carrying amount of the asset under construction. Borrowing costs may include interest expense calculated using the effective interest method (IAS 39), finance charges in respect of finance leases (IAS 17), or certain exchange differences arising from foreign currency borrowings. The related borrowing costs are then matched against revenues when the lots are sold. An entity should begin capitalizing borrowing costs on the commencement date. If funds are borrowed specifically for the purpose of obtaining a qualified asset, the interest costs incurred thereon should be deemed eligible for capitalization, net of any interest earned from the temporary investment of idle funds.