Depreciation rate calculation helps you to measure the loss in value of a certain asset over time due to age, wear and tear, and other external factors. This method is frequently used by businesses when calculating their financial assets for budgeting and forecasting purposes. By understanding the rate at which an asset depreciates, you can accurately calculate how much an item will be worth in the future. To begin your depreciation rate calculation, start with the original purchase price, then adjust it to reflect inflation, if needed. Next, consider the estimated useful life of the asset, and determine what percentage of that total should be applied as the depreciation rate. Finally, use this rate to calculate the current estimated value of the item.