In accounting the terms depreciation, depletion and amortization often involve the movement of costs from the balance sheet to the income statement in a systematic and logical manner.

For example, the systematic expensing of the cost of assets such as buildings, equipment, furnishings and vehicles is known as depreciation. The systematic expensing of the cost of natural resources is referred to as depletion. The systematic expensing of other long-term costs such as bond issue costs and organization costs is referred to as amortization.

Depreciation, depletion and amortization are also described as noncash expenses, since there is no cash outlay in the years that the expense is reported on the income statement. As a result, these expenses are added back to the net income reported in the operating activities section of the statement of cash flows when it is prepared under the indirect method.

The term amortization is also used to indicate the systematic reduction in a loan balance resulting from a predetermined schedule of interest and principal payments.