Twenty Per Cent for Every Asset
The asset register used to draw a downward value line that was honest about itself: one flat twenty per cent a year, applied to a building and a laptop alike, reconciled to nothing. Here is why that was the right shape for it to have, what a figure your accountant can use needs instead — and the net book value that replaced it.
Every asset on the chart reached zero in exactly five years. The generator, the delivery van, the office block and the four-year-old laptop: five years each, to the day.
Updated 14 October 2026
The dashboard now shows real net book value from each asset's depreciation profile; assets with no profile are carried at cost and counted. The flat twenty-per-cent chart this post takes apart has been replaced: the figure is cost less the depreciation the monthly run has posted, today and as a trend, with disposed and retired assets left out. What follows describes the old chart, and why it was built the way it was.
Our take
A written-down value chart on an asset register is useful as a shape and dangerous as a figure, and the difference is entirely in how it is labelled. Ours applied a single straight-line rate of twenty per cent a year to every asset in the register, floored the result at zero, dropped assets bought later than the point on the chart and dropped assets retired before it. It was captioned, on screen, as indicative only, with the rate named and the words "not book value and not posted to the ledger" underneath. That caption was the feature while the book figure lived elsewhere, in the depreciation register in Accounting. Since 14 October 2026 the dashboard reads those postings directly, so the shape and the figure are one number. A finance team asked us to make the maths cleverer once, and the honest answer is that a more precise wrong number would be worse than an obviously rough one — because the precise version stops being questioned.
What the chart did
For each point in the period you had selected, the register walked every asset that had both a purchase date and a purchase cost. Assets bought after that point were skipped. Assets retired on or before it were skipped. What remained was reduced by twenty per cent of its original cost for every year elapsed since purchase, with the year counted as 365.25 days so leap years landed where they should. If the result went below zero, zero was used. The points were added up, and that sum was one dot on the line.
Three assets, three years in
The proportions are identical because the rate was identical. Whatever your accountant would do with a van, a laptop and a fit-out, it would not be this — and the chart said so in its own subtitle.
What a figure your accountant can use needs
The distance between an indicative shape and a book value is four specific things, and each of them is a decision somebody has to make and record rather than a calculation somebody has to run.
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A rate per class
Motor vehicles, computers, furniture, buildings and plant depreciate at different rates in every jurisdiction and in every set of accounting policies. One rate for all of them was the single largest source of error in the old chart, and it is also the easiest thing to fix, because the register already carries a category on every asset.
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A method per class
Straight line takes the same amount off each year. Reducing balance takes a percentage of what is left, so it never quite reaches zero and it front-loads the charge. Which one applies is a policy choice, and the two produce visibly different lines from the same asset.
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A residual value
Most assets are worth something at the end of their useful life, and the depreciable amount is cost minus that residual. Treating residual as zero was why everything on the old chart terminated rather than flattening.
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A journal posting
This is the one that turns a chart into an accounting record. A depreciation charge is an expense in the period and an addition to accumulated depreciation on the balance sheet. Until that entry is written, the register and the ledger are describing the same assets in two unconnected numbers.
Why the rough version was the safer one to ship
A chart labelled "indicative, twenty per cent flat, not book value" gets questioned by the first person who reads it, which is the correct outcome. A chart that applied per-class rates but still posted nothing to the ledger would look authoritative, get copied into a board pack, and disagree with the audited accounts by an amount nobody could trace. The gap between the two is not accuracy. It is how loudly the figure announces what it is.
What the register does hold, precisely
Everything a depreciation engine would read is already recorded per asset. That is what makes this a scoping conversation rather than a rebuild.
- Purchase date and purchase cost, which are the two inputs the chart already uses and the two a real engine starts from.
- A category, free text today, which is where a per-class rate would attach.
- An ownership type — owned, leased or borrowed — which matters because a borrowed asset should not be depreciating in your accounts at all.
- A retirement date, a retiring user and a stated reason, so the point at which an asset leaves the calculation is a recorded event rather than an inference.
- A condition and a status, which are operational facts rather than accounting ones, and are the right basis for a replacement decision whatever the value figure says.
The chart was not wrong. It was imprecise on purpose, and it said which.
Reading the line for what it is good for
Used as a trend rather than a total, the line answers real questions. A register whose value falls steadily and never steps up is a register nobody is adding to, which usually means capital purchases are being expensed somewhere else or assets are being bought and never registered. A line that drops sharply in one month is a retirement or a disposal, and it should correspond to a decision somebody made. A flat line on a growing business is worth a conversation.
What the old line could not answer was what the assets are worth. For that, the figure has to come from the ledger, and the ledger has to be receiving a depreciation charge — which is the fourth item on the list above. That part ships: an asset given a depreciation profile in Accounting carries its own method, useful life or rate, and residual value, and a monthly run posts its charge. Since 14 October 2026 the dashboard line is drawn from those postings, so for profiled assets the register and the ledger agree by construction. An asset with no profile is carried at cost and the dashboard counts it, which makes that count the first number to drive to zero.
From a posted charge per asset to a schedule per class
The monthly posting ships, per asset. What remains is setting policy once per class and reporting on top of it — a defined piece rather than an open-ended one.
A rate and method per class
A table of asset classes, each with a rate, a method and a residual percentage, and a class on each asset that defaults its depreciation profile from its category.
A fixed asset note
Cost, additions, disposals, accumulated depreciation and net book value per class, in the shape the note to your accounts expects.
We publish scope, not dates.
Scope a depreciation engineWhat AWRA OpsHub does today
- An asset register holding purchase date, purchase cost, currency, category, ownership type, condition, status, risk level and a full movement history per asset.
- Net book value on the assets dashboard, today and as a trend by day, week, month or year: cost less the depreciation the monthly run has posted for each profiled asset, with assets that have no depreciation profile carried at cost and counted, and disposed or retired assets excluded. It replaced the flat twenty-per-cent chart on 14 October 2026.
- Retirement as a recorded event carrying a date, the user who retired the asset and a stated reason, so an asset leaving the register leaves a trail.
- An ownership type per asset, which is the field that separates what you own from what you hold.
- A general ledger with a chart of accounts, journals and financial statements.
- A depreciation profile per asset in Accounting: straight line or reducing balance, a useful life or annual rate, and a residual value the charge never goes below.
- A monthly depreciation run posting the charge to depreciation expense and accumulated depreciation, catching up any month that was skipped, so the register figure and the ledger figure are the same figure.
- Disposal posted to the ledger, with proceeds and the gain or loss, and charges stopped at retirement.
More we can add to your workspace
- A depreciation rate and method set once per asset class — motor vehicles, computers, buildings and plant each defaulting their own rate, method and useful life. Each asset carries its own today; the class table that sets them is being built.
- A fixed asset note setting out cost, additions, disposals, accumulated depreciation and net book value per class in the layout your accounts expect.
- A capital allowance schedule kept alongside the accounting one, since the rates a tax authority allows and the rates your policy uses are rarely the same and both need to exist.
- A revaluation path for classes carried at valuation rather than cost, with the surplus taken to reserves.
Where we point you to a specialist
- We will not choose your depreciation rates for you. A rate is an accounting policy judgement about useful life, it is reviewed by whoever signs your accounts, and a default we published would become the number an organisation defends to an auditor on our authority rather than on theirs. We build the engine and you or your accountant set the rates in it.
- Where a tax authority prescribes capital allowance rates that differ from your accounting policy, both schedules belong in the system and the reconciliation between them belongs to your tax adviser. We will hold the numbers and produce the schedules; the position taken on a return is theirs to sign.
- An impairment is a judgement that an asset is worth less than its carrying amount, and it is one we will keep declining to make automatically from condition or age. The system can flag an asset for review; deciding that it is impaired is a decision with a person behind it.
The class rate table is the contained half of this, because the monthly posting already runs per asset and every input already exists. The note and the allowance schedule are reporting on top of it.
Five questions to ask about any depreciation figure
Where does this number come from?
A good answer sounds like
A named rate and method, per class.
What ours actually is
Each asset's own depreciation profile — its method, rate or useful life and residual — as posted by the monthly run. Until 14 October 2026 it was one flat twenty per cent on original cost, named in the caption.
Does it agree with the general ledger?
A good answer sounds like
Yes, and here is the journal.
What ours actually is
Yes. The dashboard reads the same postings the depreciation register makes to the ledger; an asset with no profile is carried at cost and counted rather than written down at a rate we picked.
What happens to a retired asset?
A good answer sounds like
It leaves the calculation on its retirement date.
What ours actually is
Exactly that — disposed and retired assets are excluded, and the retirement carries a date, a user and a reason.
Is there a residual value?
A good answer sounds like
Yes, per class.
What ours actually is
Per asset rather than per class: each depreciation profile carries its own residual and the charge stops there. The old chart treated residual as zero, which is why every line ended at five years.
Can I use this in my accounts?
A good answer sounds like
Yes, if it comes from the ledger.
What ours actually is
For profiled assets the dashboard figure is the posted figure, so it agrees with your ledger. Check the count of assets carried at cost first: those have not been depreciated yet, and your accountant should set them up before the figure goes into a board pack.
Decide whether you need a shape or a schedule
Plenty of organisations genuinely need the first and think they need the second. It is a short conversation, and the answer usually turns on whether anybody is being asked to sign the number.
Talk through asset valuationFrequently asked questions
Why was it twenty per cent rather than a rate per asset class?
Because a single rate was obviously approximate and a table of rates would not have been. The chart existed to show whether the register was being maintained and whether value was leaving it, and one flat rate answered that. Per-class rates would have made the figure look like a book value, and a book value that posted nothing to the ledger would have been the most misleading kind of number an asset register could display. Since 14 October 2026 the question no longer arises: the dashboard shows net book value from each asset's own depreciation profile.
Does anything post depreciation to the accounts today?
Yes — the depreciation register in Accounting, not this chart. Give an asset a depreciation profile there, with its method, useful life or rate and residual value, and a monthly run posts the charge to depreciation expense and accumulated depreciation, and a disposal posts with its gain or loss. The flat-rate chart that used to sit on the asset register was replaced on 14 October 2026 by net book value read from those postings, with assets that have no profile carried at cost and counted.
What happened on the chart when an asset was retired?
It was excluded from every point on or after its retirement date, so the line stepped down by that asset's remaining indicative value at the moment it left. That made disposals visible as steps, which was one of the more useful things the trend did. The net book value trend that replaced it keeps that behaviour: disposed and retired assets are excluded, so a step nobody can explain is still worth investigating.
Were leased and borrowed assets included?
Every asset with a purchase date and a purchase cost was included, whatever its ownership type. In practice a borrowed asset usually had neither, so it fell out of the calculation by having no cost rather than by being recognised as somebody else's. On today's dashboard an asset with a cost and no depreciation profile is carried at cost and counted, so check the ownership type of anything in that count: an asset you do not own should not be depreciating in your accounts.
Could I change the rate?
Not on that chart — the rate was a literal in the code rather than a setting, deliberately, because a configurable single rate would have invited an organisation to tune one number until the line looked right. Today the configuration that matters is a method, a rate and a residual, which each asset carries in its depreciation profile, and the dashboard follows what those profiles post; setting them once per class is the table being built.
What should we use for our year-end figures?
Your ledger and your accountant. The register is the operational record of what you own, where it is and who has it, and it is the right place to start a fixed asset note from — but the figures in the accounts should come from posted entries, which is now what the assets dashboard shows as well.
