What Is Amortisation?

Amortisation is the accounting practice of spreading the cost of an intangible asset - software, a patent, a licence, a trademark - over its useful life, instead of expensing the whole purchase in the year it happened. It is the intangible twin of depreciation: both turn one big purchase into a series of smaller annual costs that match the years the asset is actually used. Amortised assets sit on the balance sheet alongside physical equipment in the fixed asset register, losing a slice of book value each year.

The word carries three meanings that searches tend to blur together. The dominant one - the focus of this page - is the accounting sense above. The second is the loan or mortgage sense: paying off debt in instalments. The third is the “amortisation vs depreciation” comparison. We cover all three below, starting with the accounting meaning, the formula, and a worked example. (On the spelling: “amortisation” with an s is British English and “amortization” with a z is American English; the concept is identical.)

What you will learn

• Amortisation vs depreciation
• What gets amortised
• The amortisation formula
• A worked example: a software licence
• How amortisation shows up in the accounts
• Finite vs indefinite useful life (and why goodwill is different)
• Software: when it is amortised and when it is just an expense
• Common mistakes with amortisation
• The other amortisation: loans
• Amortisation in practice

Amortisation vs depreciation

The mechanics are near-identical; the asset type differs. Depreciation covers things you can drop on your foot - vans, machinery, laptops. Amortisation covers things you cannot: rights, licences, and other intangibles.

Two practical differences follow. Amortisation is almost always straight-line - equal amounts each year - because intangibles rarely have a meaningful pattern of physical wear. And intangibles are usually assumed to be worth nothing at the end: a five-year-old delivery van has a resale market, an expired licence does not, so the residual value is normally taken as zero.

What gets amortised

• Perpetual software licences - bought outright rather than subscribed to; by far the most common amortised asset in small businesses.
• Patents, copyrights, and trademarks - amortised over their legal or useful life, whichever is shorter.
• Operating licences and franchises - the right to run a route, sell a brand, or operate in a regulated market.
• Acquired intangibles - customer lists or brand value bought as part of an acquisition.

What does not get amortised: monthly SaaS subscriptions (expensed as ordinary operating cost - nothing lasting was bought), and small one-off purchases below the capitalisation threshold, which are simply expensed regardless of type.

The amortisation formula

The standard calculation is straight-line and short:

Annual amortisation = (cost - residual value) / useful life (in years)

Residual value is the amount you expect the asset to be worth at the end of its life. For intangibles that is almost always nothing - an expired patent or a retired licence has no resale market - so the formula usually simplifies to:

Annual amortisation = cost / useful life

The two inputs you need come straight off the asset record: the purchase price (cost) and the expected useful life in years. Multiply the annual figure by the number of years elapsed and you have the accumulated amortisation; subtract that from cost and you have the current book value. That is the whole arithmetic - the hard part in practice is not the maths but knowing the cost and start date when year-end arrives.

A worked example: a software licence

A company buys a perpetual design-software licence for €6,000 and expects to use it for three years. Straight-line amortisation gives €6,000 / 3 = €2,000 per year.

Tracing it through the accounts year by year:

Each year a €2,000 expense lands on the income statement, the accumulated amortisation contra-account grows by €2,000, and the net book value falls by the same amount until it reaches zero - though the company may keep using the licence for as long as it remains useful.

If the software became unusable early - say the vendor ends support in year two - the remaining book value would not quietly tick on; it would be removed through an impairment or an asset write-off.

How amortisation shows up in the accounts

Amortisation touches two financial statements at once. The annual charge - the amortisation expense - lands on the income statement, where it is usually folded into a single “depreciation and amortisation” line rather than shown on its own. On the balance sheet, the charges accumulate in a contra-asset account called accumulated amortisation, which is netted against the intangible’s original cost. That is why book value (also called net book value) equals cost minus accumulated amortisation: the original purchase price stays on the books, and the running total of amortisation sits beside it, pulling the carrying amount down each year.

The crucial point most everyday “expense” explanations miss: amortisation is a non-cash expense. The money actually left the business on the day the asset was bought. The yearly charge is just an accounting entry that spreads that earlier outflow across the years of use - no further cash moves. This is exactly why amortisation (with depreciation) is added back when calculating EBITDA and in cash-flow statements: it reduces reported profit without touching the bank balance.

None of this works without clean records. The schedule is driven by three fields on each asset - purchase price, purchase date, and expected useful life - so keeping those captured at the point of purchase is what makes the year-end calculation trivial rather than a forensic exercise.

Finite vs indefinite useful life (and why goodwill is different)

Only intangibles with a finite useful life are amortised. A three-year software licence, a patent with a fixed legal term, a franchise agreement that runs for a set period - all have an end date, so their cost is spread over that span.

Some intangibles have an indefinite useful life: there is no foreseeable limit to how long they will generate value. Certain established brands fall here, and so, under both major accounting frameworks, does goodwill at larger and public companies. These are not amortised. Instead they are tested for impairment each year - the business checks whether the asset is still worth its carrying amount and writes it down only if it is not. The logic is that amortising something with no estimable life would be an arbitrary guess, whereas an annual impairment test reflects what actually happened.

The split is most visible with goodwill. The general rule is no amortisation, impairment-testing instead - but some private-company accounting regimes permit amortising goodwill over a capped number of years to keep things simpler for smaller firms. Which path applies depends on the framework a business reports under; either way, the useful life judgement is what decides whether an intangible is amortised at all.

Software: when it is amortised and when it is just an expense

Software is where most small businesses meet amortisation, and the question that trips people up is simple to state: do you amortise it, or just expense it as you go? The deciding test is control and ownership, not the size of the cheque.

• You control a lasting asset → capitalise and amortise. A perpetual software licence you bought outright, or software your team built or commissioned for internal use, is an asset you control going forward. Its cost goes on the fixed asset register and is amortised over its expected useful life, exactly like the worked example above.
• You only access a vendor’s software → expense it. A monthly or annual SaaS subscription buys access for the period, not a lasting asset. You never own anything, so there is nothing to capitalise - the subscription is expensed as it is incurred, the same as rent or electricity.

There is a wrinkle worth flagging: when a business signs up for a cloud service, the configuration and implementation costs - setting it up, migrating data, customising it - are treated separately under modern accounting rules and are often expensed rather than capitalised, because they relate to a service you access rather than an asset you own. The headline rule still holds: if you bought something lasting that you control, you amortise it; if you are renting access, you expense it. Whether a purchase clears the capitalisation threshold in the first place is a separate gate to apply before any of this.

Common mistakes with amortisation

The arithmetic is easy; the errors are almost always about records and judgement.

• Treating a SaaS subscription as an amortisable asset. A recurring subscription is an operating expense, not an asset - capitalising it overstates the balance sheet and understates current costs.
• Forgetting to stop or adjust the schedule. When an intangible is impaired, written off, or retired early, the amortisation schedule has to change to match. Letting it run on its original path leaves a phantom asset on the books.
• Setting an unrealistic useful life. Stretching a three-year licence to ten years to flatter profit, or guessing a life with no basis, distorts every year that follows. Base it on the legal term or genuine expected use.
• Losing the paperwork. The single most common real-world failure: the purchase invoice goes missing, so at year-end nobody is sure what the asset cost or when it started. Without those two numbers the schedule cannot be built at all.

The other amortisation: loans

The same word also describes repaying a loan in instalments, where each payment covers that period’s interest plus part of the principal. A loan amortisation schedule shows that split over the term: in the early years most of each payment is interest, and as the balance falls the principal portion grows. (The asset sense has a schedule too - a table of declining book value, like the worked example above - so the word “schedule” turns up on both sides.) The two meanings share one idea - spreading an amount over time - but the loan sense belongs to financing, not asset accounting. If a search led here from a mortgage context, that is the meaning you want.

Amortisation in practice

As the mistakes above show, the recurring small-business failure is not the arithmetic - it is losing track of which licences exist, what they cost, and when they were bought, so year-end becomes a hunt through old invoices. Keeping licences in the same register as the hardware they run on, with purchase date, price, and expected useful life on each record, makes the schedule a five-minute job. AMPthilly’s register holds digital assets such as software licences alongside physical equipment, with purchase price, dates, and expected useful life per record and CSV export for finance.

FAQ

What is the difference between amortisation and depreciation? Both spread an asset’s cost over its useful life; the difference is what kind of asset. Depreciation applies to tangible assets - vehicles, machinery, laptops - while amortisation applies to intangibles such as software licences, patents, and trademarks. In practice amortisation is almost always straight-line, and intangibles are usually assumed to have no residual value at the end, whereas physical assets often retain some resale worth.

What assets are amortised? Purchased intangibles with a finite useful life: perpetual software licences, patents, copyrights, trademarks, licences to operate, and acquired customer relationships. Monthly SaaS subscriptions are not amortised - they are simply expensed as they occur, because nothing lasting was bought. Goodwill is a special case: under some accounting frameworks it is amortised, under others it is not amortised at all but tested each year for impairment instead.

How do you calculate amortisation? Use straight-line: annual amortisation = (cost - residual value) / useful life in years. Because intangibles usually have no resale value, residual value is normally zero, so the formula simplifies to cost divided by useful life. A €6,000 licence used for three years amortises at €2,000 a year.

Is amortisation a cash expense? No. Amortisation is a non-cash expense: the money left the business when the asset was bought, and the annual charge is just an accounting entry that spreads that cost over later years. Because no cash moves, it is added back when calculating EBITDA and in cash-flow analysis.

Where does amortisation appear on the financial statements? In two places. The yearly amortisation expense hits the income statement, usually inside a combined “depreciation and amortisation” line. On the balance sheet the charges build up as accumulated amortisation, a contra-asset netted against the intangible’s original cost, so book value equals cost minus accumulated amortisation.

Is amortisation spelled with an s or a z? Both are correct and mean the same thing. “Amortisation” with an s is British English; “amortization” with a z is American English. The accounting concept is identical - only the spelling convention differs.

Is amortisation the same as paying off a loan? It is the same word doing a second job. Loan amortisation means repaying debt in scheduled instalments where each payment covers interest plus a slice of the principal - an “amortisation schedule” shows that split over the loan’s life. Accounting amortisation, the sense used in asset management, means expensing an intangible asset’s cost gradually. The shared idea is spreading an amount over time.

The takeaway

Amortisation spreads the cost of a finite-lived intangible - most often a software licence - across the years it is used, by the formula cost divided by useful life. It is a non-cash expense that shows up as an annual charge on the income statement and as accumulated amortisation netted against cost on the balance sheet. Get the inputs right - what the asset cost, when it started, and how long it will last - and the schedule writes itself. The only hard part is keeping those records, which is exactly where a single register earns its keep.

Related terms

• Capitalisation Threshold - the cost line below which purchases are expensed, not amortised
• Fixed Asset Register - where amortised intangibles live alongside depreciated equipment
• Impairment - the write-down when an intangible loses value ahead of schedule
• Residual Value - the end-of-life value, usually zero for intangibles
• Asset Write-Off - removing a dead asset’s remaining book value entirely
• Useful Life - the span the cost is spread across, and what decides if an intangible is amortised at all
• Net Book Value - cost minus accumulated amortisation; what the asset is carried at

Tools that make this easier

AMPthilly keeps software licences and other digital assets in the same register as your physical equipment, each record carrying purchase price, purchase date, and expected useful life - the three inputs an amortisation schedule needs. Documents like the purchase invoice attach to the asset so they are not lost by year-end, the full history stays on the record, and finance can pull a CSV export when the schedule is due. Start free - no credit card required - or talk to us about your setup.