Depreciation: why your assets lose value

You bought a van for the business, or an oven, or a few computers. You paid, say, a hundred thousand all at once. But that machine doesn't wear out today: it'll serve you for several years. So, is it fair to charge that whole cost to this month? No. And that's where depreciation comes in.

Depreciation sounds like an accountant's topic, but the idea is common sense. It's the way to spread the cost of something that lasts years across those years, instead of dumping it all at once. Understanding it helps you see your real profit and avoid surprises.

What it is, in plain words

Depreciation is the accounting method that spreads the cost of an asset across its useful life, recognizing that it loses value as it is used.

An asset is something you buy to use in the business for a long time: a machine, a vehicle, furniture, equipment. Unlike the goods you sell or the coffee you drink, these things last years and gradually wear down. Depreciation puts that wear into numbers.

Depreciation recognizes that the asset loses value as it is used, allocating its cost over its useful life.

The most common method: straight-line

There are several ways to calculate depreciation, but the simplest and most popular is straight-line. It assumes the asset loses the same amount of value each year, giving a constant, easy-to-predict expense.

To calculate it you need three numbers:

• The cost: what you paid for the asset.
• The salvage value: what it'll be worth at the end of its useful life, when you no longer use it.
• The useful life: how many years you expect to use it.

The formula is direct: subtract the salvage value from the cost, then divide by the years of useful life. That gives you how much it depreciates each year.

An example with numbers

Imagine you buy a machine for 100,000. You estimate that at the end of its useful life you could sell or scrap it for 20,000, that's its salvage value. And you expect to use it for 5 years.

The part that actually wears down is 100,000 minus 20,000, that is 80,000. Spread across 5 years, that's 16,000 per year. That's your annual depreciation: every year, that machine costs you 16,000 in your books, even though you don't take the money out of your pocket.

Why it pays to understand it

Beyond formal accounting, depreciation gives you three practical things. First, a real picture of your profit: if you buy an expensive machine and charge it all in one month, that month looks like a disaster and the following ones like a mirage. Second, it reminds you that your equipment ages and will need replacing sooner or later, so you can save toward it. Third, in many countries depreciation has tax effects, worth checking with your accountant.

The reason straight-line dominates is practical: it's easy to calculate, easy to audit, and reflects assets that lose value evenly. It does have a limit: it doesn't capture things that age fast, like computers, which become obsolete before they wear out.

Takeaway

Depreciation isn't an accounting trick, it's honesty with your numbers. It recognizes that what you buy to work with loses value over time and spreads that cost across the years it serves you. With the straight-line method, subtract the salvage value, divide by the years of use, and you're done. Your profit looks more real and your replacements catch you less by surprise.

Sources

• Corporate Finance Institute — https://corporatefinanceinstitute.com/resources/accounting/straight-line-depreciation/
• Investopedia — https://www.investopedia.com/terms/d/depreciation.asp
• Investopedia — https://www.investopedia.com/terms/s/straightlinebasis.asp