An asset depreciation calculator turns the abstract idea of an asset losing value into a concrete number you can act on: plug in what you paid, how long you expect to use it, and what it might be worth when you're done, and you'll get the exact amount to write off each year. Every method below models the same basic reality: wear and tear, and eventually obsolescence, chip away at what an asset is worth over time, whether that asset is a delivery van, a laptop, or a warehouse full of equipment. This guide walks through each method, shows you the formulas behind the numbers, and explains what the results actually mean for your business.

How Depreciation Calculation Works

Every depreciation calculator asks for the same three numbers: what you paid for the asset — its purchase price, sometimes called the asset cost — what you expect to recover when you're finished with it, the salvage value, sometimes called residual value or scrap value, and how many years you plan to use it, its useful life.

Feed those into the formula for whichever method you choose, and the calculator returns your depreciable asset value — the total amount written off over the asset's life — along with a yearly depreciation rate that tells you how much of that value to expense each year. Getting this figure right matters beyond your own records — lenders, buyers, and year-end financial statements all rely on an accurate number, not a rough guess.

Enter what you originally paid for the item.
Enter the amount you expect to recover when it's retired.
Choose a method and set the depreciation years for the asset.
Read off the resulting value for each period.

Choosing the Right Depreciation Method: Asset Depreciation Explained

Depreciation is fundamentally a reduction in value, and the right depreciation method depends on how the asset actually loses that value in practice — some lose it evenly, others lose it fast up front. Spreading a large purchase's cost out, instead of recording it all at once, keeps it from distorting your income statement in the year you bought it; accountants call this distributing the cost, and it's the entire point of depreciation.

Straight-Line Depreciation

This is called straight line depreciation, and it's the simplest method: the asset loses the same dollar amount every year.

$$ \text{Annual Depreciation} = \frac{\text{Cost} - \text{Salvage}}{\text{Life}} $$

A $50,000 asset that's expected to be worth $5,000 after five years depreciates by $9,000 annually under this method.

Declining Balance and Double Declining Balance Depreciation

For equipment that loses most of its value early — computers, vehicles, specialized machinery — the declining balance method front-loads the expense instead of spreading it evenly. This is an example of accelerated depreciation: it artificially reduces profit in the near term and increases it later, which can influence reported cash flows.

$$ \text{Depreciation} = \text{Value} \times \text{Rate} $$

Set the depreciation factor to 2 to model double declining balance specifically. Double declining balance is the most common version — it simply doubles the straight-line rate and ignores the usual recovery amount until book value each year drops to meet it, at which point depreciation stops. For example, a $50,000 asset depreciated at a 20% rate loses $10,000 in year one, dropping its value to $40,000; year two loses 20% of that new figure, or $8,000, taking it down to $32,000 — and so on until the number approaches what's left to recover.

Sum-of-the-Years'-Digits Depreciation

Also known as sum of the years digits depreciation, this method works well for assets that produce more value early in life and taper off afterward.

$$ D_t = (\text{Cost} - \text{Salvage}) \times \frac{n - (t-1)}{1 + 2 + \cdots + n} $$

Here, n represents the asset's useful life in years, so the fraction shrinks a little more with every passing year. For a 5-year asset, the year-one factor is 5⁄15, the year-two factor is 4⁄15, and so on down to 1⁄15 in the final year — front-loading close to a third of the total depreciation into year one alone.

Units of Production Depreciation

Rather than counting years, units of production ties the expense to actual output — a natural fit for manufacturing equipment.

$$ \text{Depreciation} = (\text{Cost} - \text{Salvage}) \times \frac{\text{Actual}}{\text{Estimated}} $$

If an asset produces more units in a given year — measured against its estimated total production over its lifetime — it depreciates faster that year based on actual production instead of the calendar.

Comparing the Options at a Glance

Straight-line — equal expense every year; simplest to forecast.
Declining balance — faster write-offs early, slower later.
Units of production — tied to actual output instead of time.

Different businesses depreciate similar assets on completely different schedules depending on which method they choose. Whichever you pick, total depreciation relative to the original asset cost ends up the same by the time the asset reaches that recovery value — only the timing changes.

Salvage Value and Useful Life in Your Depreciation Calculation

The table below shows how those two numbers play out together for a sample asset under the straight-line method.

Sample 5-year straight-line depreciation schedule for a $50,000 asset with a $5,000 salvage value
Year	Value at Start	Depreciation Expense	Value at End
1	$50,000	$9,000	$41,000
2	$41,000	$9,000	$32,000
3	$32,000	$9,000	$23,000
4	$23,000	$9,000	$14,000
5	$14,000	$9,000	$5,000

Whatever method feeds the table, the pattern is the same — value declines each period until it reaches the endpoint you set at the start.

Partial-Year Depreciation and Real-World Asset Depreciation Scenarios

Not every asset arrives neatly on the first day of your fiscal year. Partial year depreciation handles the case where an asset starts service in, say, March instead of January — you begin expensing the asset from the month it entered service, using a convention such as half-year or exact day count to prorate that first period.

Get the convention wrong and the asset value on your books in year one will be off by weeks of depreciation, which then has to be corrected in every later period too.

Car Depreciation Calculator: How Vehicles Lose Resale Value

The same math applies to a very familiar case: the moment you drive a new vehicle off the lot, it starts to depreciate in value, often losing a fifth of its price in the first year alone. Real-world vehicle values follow a depreciation curve that's steepest early and flattens out later, closer to a declining balance pattern than an even one.

What you actually get back when you sell is the resale value, which tracks the calculated figure only loosely — mileage, condition, and market demand for that specific make and model all push the real number up or down from a plain estimate. Treat the output as a starting point for loss in value, not a guaranteed trade-in quote. Luxury brands and electric vehicles often lose value faster than economy models in the first three years, then the rate of loss tends to level out closer to the segment average. Banks and lenders sometimes build a simple financial calculator into their own loan software for exactly this kind of estimate.

Depreciation Tool Uses for Insurance Claims and Business Bookkeeping

Beyond company finance teams, this kind of tool shows up in insurance claims too — adjusters rely on a similar depreciation estimator, but one built from real-world claims data instead of accounting formulas. Instead of a useful-life calculation, these tools work from a database of typical wear, damage, aging, and expected lifespan by item category, from major appliances to office equipment, and report a value based on the item's cost new rather than the original receipt. Two items with the same cost new can carry very different depreciated values depending on condition — that's sometimes called value depreciation in adjuster shorthand.

For tax filings, what you paid is often called the cost basis rather than the purchase price. For everyday bookkeeping, correct depreciation matters because most business purchases over a certain dollar threshold aren't tax-deductible all at once — equipment, vehicles, and office furniture generally have to be depreciated and expensed a little at a time instead, which is one of the more error-prone parts of small business finance. Getting the schedule right the first time also saves you from redoing tax deductions later because an asset's depreciation was recorded incorrectly.

Correct numbers also directly affect the taxes you owe each year, not just your internal books, and they feed into broader financial planning — from loan applications to equipment replacement budgets. A schedule that's even slightly off can throw off a loan application's collateral value or misstate what a company is really worth on paper, long after the original purchase is forgotten. Whatever the reason you're running the numbers — accounting, insurance, or simply deciding whether to sell an old piece of equipment — the formulas above are what every calculator like this one is doing behind the scenes, alongside whatever other financial calculators you already rely on.