Albert Barnes Commentary Luke 14:28

"For which of you, desiring to build a tower, doth not first sit down and count the cost, whether he have [wherewith] to complete it?" — Luke 14:28 (ASV)

Intending to build a tower. See Matthew 21:33. A tower was a place of defence or observation, erected on high places or in vineyards, to guard against enemies. It was made high, so as to enable one to see an enemy when he approached; and strong, so that it could not be easily taken.

Counteth the cost. Makes a calculation of how much it will cost to build it.