Net Book Value

Net book value is the value of an asset on the books of the company. For example, suppose a company buys a machine with a five-year useful life for $5,000 cash. It debits Fixed Assets $5,000 and credits Cash $5,000. The machine's net book value is currently $5,000. After one year, the company records depreciation by debiting Deprecation Expense $1,000 ($5,000/5) and crediting Accumulated Depreciation for $1,000. The machine's net book value is now the original cost ($5,000) less the accumulated depreciation ($1,000), or $4,000. The problem with net book value is whether it reflects economic reality or merely accounting convention. The net book value of $4,000 probably isn't what the machine would fetch at public auction. Further, the net book value calculation itself is an estimate, because the machine's exact useful life is unknowable. Nevertheless, net book value does give financial statement readers a rough idea of asset values. Note that net book value is similarly used to value long-term liabilities which are amortized, such as bonds. Finally, net book value is often simply expressed as the book value.