The Depreciation Straight Line Method is a business tool used to calculate the rate of depreciation associated with an asset. It factors in the cost of acquisition and the residual value of the asset over its useful life, dividing it evenly into equal periods carrying the same amount of depreciation expense. This method can also be referred to as uniform depreciation, linear depreciation, or “write-off” methodology; it’s the most widely used way for businesses to estimate the cost of assets through their useful lives.