Book Value Calculator
Work out what an asset is worth on the balance sheet, how far that sits from what it would actually fetch, and what the difference costs in tax on disposal.
Book Value Calculator
Results recalculate instantly on every keystroke. Nothing you type is transmitted.
What this result does not account for
- Assumes a single asset rather than a pooled register.
- Market value is a user estimate, not a derived figure.
- Ignores impairment write-downs already recorded in prior periods.
In short: A $540,000 asset two years into a five-year straight line schedule carries $192,000 of accumulated depreciation and a net book value of $348,000. At a $400,000 market value the disposal gain is $52,000, taxed at 21% for net proceeds of $389,080.
Formula
Book value is an accounting remainder, not a market estimate. The gap between the two is where disposal gains and impairments come from.
Worked Example
- Depreciate to date. Two years at $96,000 gives $192,000 of accumulated depreciation on straight line.
- Subtract from cost. $540,000 less $192,000 is a net book value of $348,000 — 64.44% of original cost still carried.
- Compare to the market. At an estimated $400,000, the asset is worth $52,000 more than the balance sheet says.
- Compute the disposal tax. That $52,000 is a taxable gain. At 21% the tax is $10,920, leaving net proceeds of $389,080.
- Check the method effect. The same asset on double declining would carry $194,400 — $153,600 lower, on identical physical condition.
The most important output on this page is the method gap. This asset is two years old, has been used identically, and would fetch the same price on the open market under either accounting policy — yet it appears on the balance sheet at $348,000 under straight line and $194,400 under double declining. A $153,600 difference, on the same machine, driven entirely by a decision made when the asset was purchased. That is why asset-heavy balance sheets are not comparable across businesses without knowing their depreciation policies, and why a valuation resting on net asset value is only as meaningful as the policy underneath it.
Strengths & Limits Of This Model
Where this engine is strong
- Computes book value under both methods and quantifies the difference.
- Carries the disposal gain through to tax and net proceeds.
- States plainly that book value is not a valuation, and shows why.
Where it stops
- Cannot model component depreciation or revaluation frameworks.
- Does not handle partial disposals or asset transfers.
Practical Use Cases
Calculating the gain or loss on an asset sale
Proceeds less net book value is the taxable gain. Here $52,000, costing $10,920 in tax.
Identifying impairment
Market value below book is an impairment indicator and may require a write-down in the period it is identified.
Preparing a fixed asset note
Cost, accumulated depreciation and net book value are the three required figures. Build the schedule with the Straight Line Depreciation Calculator.
Assessing a net-asset-based valuation
Book values reflect policy, not worth. Cross-check against an earnings basis with the Business Valuation Calculator.
Methodology & Editorial Standards
Net book value is original cost less accumulated depreciation, and the engine computes it under both straight line and declining balance so the effect of policy is visible rather than implicit. It is an accounting remainder: the unamortised portion of a past purchase, recorded under assumptions about life and salvage fixed at acquisition. It responds to no market signal and it is not an estimate of what an asset would fetch, a point the engine states directly because net book value is routinely misread as a valuation. The comparison against an estimated market value produces the disposal gain or loss, which is the figure that actually matters on a sale: proceeds above book are taxable in the period of disposal even though the economic reality is simply that the asset depreciated more slowly than the schedule assumed, while proceeds below book generate a deductible loss and, if identified before sale, an impairment indicator that may require a write-down. The engine reports the difference in book value between the two methods at the same age on the same asset, since that gap is the clearest demonstration that the balance sheet figure reflects a policy decision rather than a physical fact. The engine implements the standard published formula for this calculation. Inputs are validated for domain and sign before evaluation, and any undefined case returns an em-dash rather than a spurious value.
Computation runs in IEEE-754 double precision at full internal precision; rounding to two decimal places occurs strictly at the display layer, so no cumulative drift enters the result. All monetary outputs use accounting presentation — grouped thousands, two decimals, negatives in parentheses — so figures can be transcribed directly into a model or working paper. Division-by-zero and out-of-domain inputs return an em-dash rather than a misleading number.
This engine was reconciled against an independent reference implementation and hand-verified for the worked example above before release. Our full five-stage review process is published on the About Us page.
Disclaimer. This calculator is provided for informational and modelling purposes only and does not constitute financial, tax, legal, medical, or engineering advice. Verify all figures with a qualified professional before acting on them.
Book Value Calculator — 20 Expert FAQs
20 analyst-written answers to the questions practitioners actually ask — optimised for voice and answer-engine retrieval.
What is net book value?
Original cost less accumulated depreciation — $348,000 here after two years of a five-year schedule.
Is book value what the asset is worth?
No. It is an accounting remainder under a policy chosen at purchase. It responds to no market signal whatsoever.
How much does the method change it?
$153,600 here. The same asset at the same age carries $348,000 on straight line and $194,400 on double declining.
What is a gain on disposal?
Proceeds less net book value. Here $400,000 against $348,000 is a $52,000 taxable gain.
Why is a disposal gain taxable?
Because depreciation already reduced taxable profit. If the asset held its value better than assumed, the excess relief is recovered.
What if market value is below book?
That is a loss on disposal, generally deductible, and if identified before sale it is an impairment indicator requiring possible write-down.
What is accumulated depreciation?
The running total charged since acquisition — $192,000 here, or 35.56% of original cost.
Does book value ever reach zero?
Only if salvage is zero. Here it stops at $60,000 and stays there while the asset remains in service.
Why do fully depreciated assets still appear?
Because they remain in use and legally owned. They sit at salvage and generate no further charge, which flatters profit.
Is book value used in valuation?
Only for asset-based approaches, and cautiously. Earnings-based valuations ignore it, because it reflects policy rather than economics.
What is carrying value?
The same figure as net book value, after any impairment write-downs. The terms are used interchangeably in practice.
How does book value affect debt covenants?
Net worth covenants are measured on book values, so depreciation policy directly affects covenant headroom without any cash changing hands.
Should I revalue assets to market?
Some frameworks permit it for property; most prohibit it for plant and equipment. It introduces volatility and requires regular independent valuation.
What happens to accumulated depreciation on disposal?
Both cost and accumulated depreciation are removed from the balance sheet, and the difference against proceeds goes to the income statement.
Does book value include improvements?
Capitalised improvements are added to cost and depreciated over the remaining life. Repairs are expensed and never appear.
Why does my balance sheet look asset-poor?
Older assets are carried at heavily depreciated values while remaining fully productive. That is normal and it understates operating capacity.
Is this book value calculator free to use?
Yes. It is free, requires no account, and has no usage limits. ApexConverter is funded by contextual advertising, never by selling user data.
Is my data sent to a server?
No. The engine runs as Vanilla JavaScript inside your browser under our Zero-Server Client-Side Execution model. Your figures are computed locally and are never transmitted, logged, or stored.
How accurate is this calculator?
It applies the standard closed-form formula in IEEE-754 double precision, rounding only at the display layer. The engine is reconciled against an independent reference implementation before release.
Does it work on mobile?
Yes. The interface is mobile-first with numeric keypad hints and is tested down to a 320-pixel viewport with no horizontal scrolling.