Depreciation on the income statement is the amount of depreciation expense that is appropriate for the period of time indicated in the heading of the income statement. The depreciation reported on the balance sheet is the accumulated or the cumulative total amount of depreciation that has been reported as expense on the income statement from the time the assets were acquired until the date of the balance sheet.
Let's illustrate the difference with an example. A company has only one depreciable asset that was acquired three years ago at a cost of $120,000. The asset is expected to have a useful life of 10 years and no salvage value. The company uses straight-line depreciation on its monthly financial statements. In the asset's 36th month of service, the monthly income statement will report depreciation expense of $1,000. On the balance sheet dated as of the last day of the 36th month, accumulated depreciation will be reported as $36,000. In the 37th month, the income statement will report $1,000 of depreciation expense. At the end of the 37th month, the balance sheet will report accumulated depreciation of $37,000.