The residual value of a non-current asset, also known as the salvage value, is the estimated value of the asset at the end of its useful life. It's the amount a business expects to receive if they sell the asset after it has been depreciated. In simple terms, it's the amount that the asset can be sold for once it's no longer useful for the business. The residual value is typically calculated based on factors such as the asset's condition, age, market demand, and expected technological advancements. It's important to note that the residual value is only an estimate, and the actual value of the asset may be higher or lower when it's eventually sold.