Net book value calculator

What you need to know

Net book value is what an asset is worth in your accounts today: its original cost minus all the depreciation (and any impairment) charged against it so far. The formula is NBV = cost − accumulated depreciation − impairment. If you already have the accumulated depreciation from your fixed asset register or ledger, enter it with the cost and the calculator does the subtraction, shows NBV as a share of cost and, if you add a sale price, the gain or loss on disposal.

If you don’t have the accumulated figure, switch to the straight-line estimate. Enter the cost, salvage (residual) value, useful life and how long the asset has been in use. Annual depreciation is (cost − salvage) ÷ useful life, accumulated depreciation is that amount × years in use, and NBV is cost minus the result. It never goes below salvage, so an asset used longer than its useful life stays at its salvage value. Fractions of a year work too: 2.5 years means two and a half years of depreciation.

A worked example: a machine that cost 12,000 with a 2,000 salvage value and a 5-year life depreciates 2,000 a year. After 2 years accumulated depreciation is 4,000 and NBV is 8,000, two-thirds of cost. Sell it for 9,000 and you record a 1,000 gain on disposal; sell it for 7,000 and you record a 1,000 loss.

NBV is a book (accounting) value, not market value or tax written-down value. Tax rules such as MACRS in the US or capital allowances in the UK follow their own schedules, so a tax value can differ from the book NBV. Confirm tax treatment with your accountant. The calculator runs in your browser, works in any currency and needs no sign-up.