The calculation for annual depreciation using the units-of-output method is

The formula for annual depreciation by means of the units-of-production method is:

(depreciable cost / estimated output) x the actual yearly output

Under the units of production method, the quantity of depreciation indicted to expense differs in direct proportion to the amount of asset usage. Therefore, a business may charge more depreciation in times when there is more asset consumption and less depreciation in times when there is a smaller amount of usage. It is the most precise method for indicting depreciation as this method relate thoroughly to the wear and tear on assets. Though, it also needs that someone should track asset usage which means that its use is commonly restricted to more luxurious assets. It needs estimation of the total usage over the life of the asset in order to come up with the amount of depreciation to identify in separate accounting period.