Which Depreciation Method Is Used in the UK for Fixed Assets?
There is no single depreciation method that UK law requires every organisation to use. Under FRS 102 and IFRS, a business chooses the method that best reflects how it actually uses an asset — most commonly straight-line, sometimes reducing balance, occasionally units of production. What trips people up is assuming that whatever method they pick also determines their tax bill. It does not. HMRC ignores accounting depreciation entirely and uses a separate system called capital allowances.
That single distinction — depreciation for the accounts, capital allowances for the tax return — explains most of the confusion finance managers, school business managers and SME owners run into when this question comes up. This guide covers both sides properly: how UK accounting standards actually require you to depreciate assets, and how that connects (or rather, does not connect) to what HMRC lets you deduct.
The Short Answer
For statutory accounts, UK entities follow FRS 102 (or IFRS, if listed or opting in) and choose whichever depreciation method best reflects the pattern in which an asset's economic benefit is consumed. The straight-line method is by far the most widely used in UK practice because it is simple, transparent, and defensible to auditors. Reducing balance is the next most common, typically for vehicles, IT equipment and plant that lose value faster in early years.
For tax purposes, depreciation is irrelevant. HMRC adds it back to your profit and instead applies capital allowances — a fixed set of statutory rates (the Annual Investment Allowance, Writing Down Allowances, Full Expensing and the Structures and Buildings Allowance) that have nothing to do with the depreciation method in your accounts.
If you take away one thing from this article: your depreciation charge and your tax deduction for the same asset are calculated using two entirely separate rulebooks. Getting this distinction wrong is one of the most common errors in SME bookkeeping.
Two Different Systems: Accounting Depreciation vs Tax Capital Allowances
Accounting depreciation exists to give a "true and fair view" of your financial position, as required by the Companies Act 2006. It spreads the cost of a fixed asset over its useful economic life so that your profit and loss account reflects the asset being consumed over time, rather than showing one enormous cost in the year of purchase.
Capital allowances exist for an entirely different reason: to let HMRC control, through tax policy, how much relief a business gets for capital spending, and when. Governments use capital allowance rates to encourage or discourage investment — increasing the Annual Investment Allowance to stimulate business spending is a lever the Treasury pulls regularly.
Because these two systems serve different purposes, they are not reconciled asset by asset. Instead, at the point you prepare your tax computation, your accounting depreciation charge is added back to profit (since it is not tax-deductible), and capital allowances are deducted instead. The result is that your accounting profit and your taxable profit are almost never the same figure.
Which Accounting Framework Applies to You
Most UK organisations fall into one of these categories, each with a slightly different depreciation rulebook:
| Organisation type | Framework | Depreciation guidance |
|---|---|---|
| Most UK private companies (SMEs) | FRS 102 (UK GAAP) | Section 17, Property, Plant and Equipment |
| Listed companies and some large groups | IFRS | IAS 16, Property, Plant and Equipment |
| Academy trusts (exempt charities) | Charities SORP, applying FRS 102, as adapted by the Academies Accounts Direction | Same principles as FRS 102, with disclosure of capitalisation threshold and useful lives |
| Registered charities | Charities SORP (FRS 102) | Same principles as FRS 102 |
| NHS bodies and other central government entities | HM Treasury's Government Financial Reporting Manual (FReM), based on IFRS as adapted for the public sector | Often includes revaluation to current value rather than historical cost |
| Local authorities | CIPFA Code of Practice on Local Authority Accounting | Broadly IFRS-based, adapted for the public sector |
FRS 102 and IFRS are closely aligned on depreciation principles — both require a systematic method that reflects the consumption of economic benefit, and both require the method and useful life to be reviewed periodically. The practical differences show up more in disclosure requirements and in how public sector bodies revalue assets, not in the basic mechanics of calculating a depreciation charge.
If you're a UK academy trust or maintained school working out how depreciation fits alongside your asset register and capitalisation threshold, our guide on managing a school asset register in the UK covers that ground in more detail.
The Depreciation Methods Used in UK Accounts
FRS 102 (paragraph 17.22) and IAS 16 both take the same position: there is no prescribed method. You select whichever one reflects how the asset's economic benefits are actually used up, and you apply it consistently. In practice, UK businesses use one of four methods.
1. Straight-line method
The most common method in UK practice. The asset's depreciable amount (cost minus estimated residual value) is spread evenly across its useful life.
Formula: (Cost − Residual value) ÷ Useful life
Worked example: A piece of office furniture costs £12,000, has an estimated residual value of £0, and a useful life of 6 years.
Annual depreciation = £12,000 ÷ 6 = £2,000 per year
Straight-line suits assets that lose value at a fairly consistent rate over time — buildings, furniture, fixtures and fittings.
2. Reducing balance (diminishing balance) method
A fixed percentage is applied to the asset's net book value (not its original cost) each year, meaning the depreciation charge is highest in the early years and tapers off over time.
Formula: Net book value × Depreciation rate
Worked example: A delivery van costs £30,000 and is depreciated at 25% reducing balance.
- Year 1: £30,000 × 25% = £7,500 (NBV: £22,500)
- Year 2: £22,500 × 25% = £5,625 (NBV: £16,875)
- Year 3: £16,875 × 25% = £4,219 (NBV: £12,656)
Reducing balance suits assets that lose value quickly when new and level off later — vehicles, IT equipment, and plant and machinery that becomes technologically outdated.
Do not confuse accounting "reducing balance" depreciation with HMRC's "writing down allowance" — both use a declining-balance calculation and the terminology overlaps, but they are different systems with different rates, different pools, and no direct relationship to each other. This mix-up is one of the most common errors we see in SME bookkeeping.
3. Units of production (usage-based) method
Depreciation is calculated based on actual usage — machine hours, mileage, or units produced — rather than the passage of time.
Formula: (Cost − Residual value) ÷ Total expected output × Units produced this year
This method suits manufacturing plant, printing presses, and vehicles where wear is more closely tied to use than to age. It requires reliable usage tracking to apply consistently, which is why many organisations avoid it unless they already log machine hours or mileage for other reasons.
4. Sum-of-the-digits and other systematic bases
FRS 102 and IAS 16 also permit any other systematic basis that reflects the pattern of consumption, including sum-of-the-years'-digits (an accelerated method similar in effect to reducing balance). In UK practice this is rare — most businesses that want an accelerated charge simply use reducing balance, which is easier to explain to auditors and easier to build into finance systems.
| Method | Best suited to | Depreciation pattern | How common in UK practice |
|---|---|---|---|
| Straight-line | Buildings, furniture, fixtures | Equal charge each year | Most common |
| Reducing balance | Vehicles, IT equipment, plant | High charge early, tapering off | Common |
| Units of production | Manufacturing machinery, high-mileage vehicles | Based on actual usage | Occasional, usage-dependent |
| Sum-of-the-digits | Rapidly obsolescing equipment | Accelerated, similar to reducing balance | Rare |
Choosing a Useful Life
Useful life is an estimate, not a fixed rule — FRS 102 requires it to reflect how long your organisation expects to use the asset, which is not necessarily the same as how long the asset could physically last. A van driven 40,000 miles a year has a shorter useful life in your accounts than the same van driven 8,000 miles a year, even though both are mechanically capable of lasting longer.
The following ranges are commonly seen in UK practice and are a reasonable starting point for discussion with your accountant — they are not statutory figures:
| Asset category | Typical useful life range |
|---|---|
| Freehold buildings | 25–50 years |
| Leasehold improvements | Length of lease (or shorter, if the asset's useful life is shorter) |
| Plant and machinery | 5–15 years |
| Motor vehicles | 4–7 years |
| IT equipment | 3–5 years |
| Fixtures and fittings | 5–10 years |
| Land | Not depreciated (unless subject to depletion) |
Land is not depreciated under FRS 102 or IFRS, because it does not have a finite useful life. Buildings sitting on that land are depreciated, but the land itself is not — a distinction that catches out anyone splitting a property purchase for the first time.
Useful life and residual value must be reviewed at least at each financial year end (FRS 102, paragraph 17.19). If your estimate changes significantly — say, you now expect a machine to last 12 years instead of 8 — you adjust the remaining depreciation charge prospectively. You do not restate prior years.
Componentisation Under FRS 102
For larger or composite assets, FRS 102 (and IAS 16) expects componentisation: splitting an asset into its significant parts and depreciating each part separately, where those parts have materially different useful lives.
The classic example is a building. The structure might have a 50-year useful life, the roof 25 years, and the heating system 15 years. Depreciating the whole building as one line, using the 50-year structural life, would understate the true cost of replacing the roof and boiler along the way.
This matters practically for your asset register, not just your accounting entries — if your auditor expects componentised depreciation, your underlying asset records need to support that level of detail, rather than treating "the building" as a single line item.
How HMRC Actually Treats Fixed Assets
This is where UK tax diverges completely from UK accounting. HMRC does not allow accounting depreciation as a deduction against profit under any circumstances. Instead, when you buy qualifying assets, you claim capital allowances — a set of statutory rates that determine how much of the cost you can deduct, and over what period, for tax purposes.
Capital allowance rates, thresholds and reliefs change frequently — often at each Budget or Autumn Statement. The rates below reflect the position widely understood at the time of writing. Always confirm current rates on gov.uk or with your accountant before relying on them for tax planning.
The main reliefs currently in use:
- Annual Investment Allowance (AIA) — gives 100% tax relief in the year of purchase on qualifying plant and machinery expenditure, up to an annual limit (£1 million per year at the time of writing). This covers the vast majority of a typical SME's capital spending.
- Full Expensing — available to companies (not sole traders or partnerships) on new, unused main-rate plant and machinery, giving 100% first-year relief with no upper limit. Introduced for expenditure from 1 April 2023 and subsequently made permanent.
- 50% First-Year Allowance — the companies-only equivalent of Full Expensing for special-rate assets (broadly, integral features and long-life assets).
- Writing Down Allowances (WDA) — for expenditure not covered by the above, relief is given at a fixed percentage of the reducing balance each year: 18% for the main pool, 6% for the special rate pool (rates as commonly applied at the time of writing).
- Structures and Buildings Allowance (SBA) — 3% per year on a straight-line basis for eligible new non-residential structures and buildings (introduced October 2018; the rate increased from an initial 2% to 3% in April 2020).
- Cars — capital allowances for company cars depend on CO2 emissions: zero-emission cars typically qualify for a 100% first-year allowance, while other cars fall into the main pool or special rate pool depending on their emissions banding.
Land is never eligible for capital allowances, in the same way it is never depreciated in the accounts.
Accounting Depreciation vs Capital Allowances, Side by Side
| Accounting depreciation | Capital allowances (tax) | |
|---|---|---|
| Governed by | Companies Act 2006, FRS 102 / IFRS | Capital Allowances Act 2001, HMRC |
| Purpose | True and fair view of financial position | Calculating taxable profit |
| Method | Chosen by the business (straight-line, reducing balance, etc.) | Fixed statutory rates set by HMRC |
| Basis | Estimated useful economic life | Prescribed percentages and thresholds |
| Tax-deductible? | No — added back in the tax computation | Yes — deducted from taxable profit |
| Reviewed how often | At least annually | Set by legislation, changes at Budgets |
| Applies to | Every UK entity preparing statutory accounts | Businesses subject to UK income tax or corporation tax |
This is why your management accounts and your corporation tax computation will show different profit figures for the same period — and why an auditor asking about your depreciation policy and your accountant asking about your capital allowances claim are, correctly, asking about two different things.
Real-World Scenarios
The manufacturer. An SME buys a £180,000 CNC machine. In the accounts, the finance manager depreciates it on a straight-line basis over 10 years (£18,000 a year), matching the manufacturer's own estimate of the machine's productive life. On the tax return, the full £180,000 is likely to qualify for the Annual Investment Allowance or Full Expensing in the year of purchase — an immediate 100% deduction that bears no resemblance to the £18,000 annual accounting charge.
The hotel refurbishment. A hotel spends £90,000 replacing kitchen equipment during a renovation. The finance team depreciates the new equipment on a reducing balance basis, reflecting how quickly commercial kitchen equipment loses value once installed. Separately, the same £90,000 is analysed for capital allowances — most of it likely qualifying as plant and machinery, some potentially falling into the special rate pool depending on what was replaced.
The academy trust. A multi-academy trust replaces a school's boiler as part of a Condition Improvement Fund-funded project. In the trust's accounts, the boiler is treated as a separate depreciable component of the building under FRS 102 componentisation rules, with its own useful life distinct from the building's structure. Academy trusts do not pay corporation tax on their charitable activities, so capital allowances are largely irrelevant here — but the accounting depreciation treatment still needs to be right for the trust's annual accounts and ESFA reporting.
The landlord. A commercial property investor constructs a new warehouse. The structure itself may qualify for the Structures and Buildings Allowance at 3% a year on a straight-line basis for tax purposes, while in the accounts, the warehouse is depreciated over its estimated 40-year useful life — a materially different rate and timeframe from the tax treatment, calculated for a materially different reason.
Common Mistakes
- Assuming the depreciation method affects the tax bill. It does not. Capital allowances are calculated independently of whatever method sits in the accounts.
- Using HMRC's "writing down allowance" rates as the accounting depreciation rate. They exist for entirely different purposes and there's no requirement — or good reason — for them to match.
- Depreciating land. Land does not have a finite useful life and should not be depreciated; only the buildings on it are.
- Never reviewing useful life estimates. FRS 102 expects at least an annual review — a useful life set five years ago on a piece of machinery that has since been used far more or less heavily than expected should be revisited.
- Treating a whole building as one depreciation line. Larger auditors will expect componentisation for material assets — a roof, a boiler and a lift wear out at different rates from the building's structure.
- Forgetting to disclose the depreciation policy. Statutory accounts need to state the methods and useful lives used, not just show the resulting numbers.
- Applying US or Indian depreciation rules by habit. If your finance team has prior experience with MACRS (US) or the Companies Act 2013 Schedule II (India), it is easy to default to unfamiliar assumptions that do not apply under FRS 102 or IFRS.
Action Checklist
- Confirm which accounting framework applies to your organisation (FRS 102, IFRS, Charities SORP, or FReM)
- Choose a depreciation method for each asset category based on how the asset is actually consumed, not habit
- Set a useful life and residual value for each category, with a reasonable evidence base
- Review useful lives and residual values at least annually
- Componentise material assets with parts that wear out at different rates
- Disclose depreciation methods and useful lives in your statutory accounts
- Keep your capital allowances tax computation entirely separate from your accounting depreciation schedule
- Check current AIA, Full Expensing, WDA and SBA rates on gov.uk before relying on them for tax planning
- Confirm land is excluded from depreciation calculations
Frequently Asked Questions
Which depreciation method is used in the UK?
There is no single method mandated by UK law. FRS 102 and IFRS both require businesses to choose whichever method — straight-line, reducing balance, units of production, or another systematic basis — best reflects how the asset's economic benefits are consumed. Straight-line is the most widely used in UK practice.
Does HMRC allow depreciation as a tax deduction?
No. Accounting depreciation is added back to profit in the tax computation and is never deductible. Instead, HMRC gives relief through capital allowances, calculated using entirely separate statutory rates.
What's the difference between depreciation and capital allowances?
Depreciation is an accounting concept, governed by FRS 102 or IFRS, that spreads an asset's cost over its useful life for financial reporting purposes. Capital allowances are a tax concept, governed by the Capital Allowances Act 2001 and set by HMRC, that determine how much of an asset's cost can be deducted from taxable profit and over what period. The two are calculated independently and rarely produce the same figures.
Is straight-line or reducing balance more common in the UK?
Straight-line is more common overall, particularly for buildings, furniture and fixtures, because it is simple and easy to justify to auditors. Reducing balance is common for vehicles, IT equipment and plant that loses value more quickly when new.
Do I have to depreciate land?
No. Land is not depreciated under FRS 102 or IFRS because it does not have a finite useful life. Buildings and structures on the land are depreciated separately.
How often should useful life estimates be reviewed?
At least annually, under FRS 102. If your estimate of an asset's remaining useful life or residual value changes significantly, you adjust the depreciation charge going forward — you do not restate previous years' figures.
What is componentisation and does it apply to my organisation?
Componentisation means splitting a large or composite asset — most commonly a building — into significant parts with materially different useful lives (structure, roof, heating system) and depreciating each separately. It applies wherever those parts are material enough that depreciating the asset as a single line would misrepresent its true cost pattern, which in practice tends to matter most for property-owning organisations and larger entities.
Do academy trusts and charities use the same depreciation rules as companies?
Broadly, yes. Academy trusts and registered charities in England follow the Charities SORP, which is itself based on FRS 102, so the depreciation principles are the same. Academy trusts additionally follow the Academies Accounts Direction, which requires disclosure of the trust's capitalisation threshold and depreciation policy.
Can I change my depreciation method once I've started?
Yes, but only if the change better reflects the pattern of economic benefit consumption — it should not be changed simply to alter reported profit. A change in method is treated as a change in accounting estimate, applied prospectively, and should be disclosed.
Conclusion
The honest answer to "which depreciation method is used in the UK" is that it depends on your organisation and your asset — but the method itself matters far less than most people assume, because it has no bearing on your tax bill. FRS 102 and IFRS give you the flexibility to choose straight-line, reducing balance, units of production, or another systematic basis, provided it reflects reality and you apply it consistently. HMRC, meanwhile, runs an entirely separate system of capital allowances that determines what you can actually deduct from taxable profit.
Getting both sides right — a defensible depreciation policy in your accounts, and an accurate, up-to-date capital allowances claim on your tax return — depends on having reliable records behind both: acquisition cost, category, useful life, and usage. That is precisely the data an asset register is built to hold, and why finance teams that keep depreciation calculations tied to a live asset register, rather than a separate annual spreadsheet exercise, spend far less time reconciling the two.
UniAsset calculates net book value, accumulated depreciation and the annual depreciation charge automatically for every asset, using straight-line or reducing balance methods configured at the category level — so the figures update as assets are added, moved or disposed of, rather than being rebuilt from scratch at year end.
Start free — no credit card required or read our guide on straight-line vs reducing balance vs double-declining balance.
Suggested Internal Links
- Depreciation Mistakes Organisations Make
- What Is Book Value of an Asset
- Fixed Asset Register
- Asset Audits
- Total Cost of Ownership
- Repair vs Replace Decision Framework
- Academy Trust Compliance
- Depreciation Under IFRS (IAS 16)
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