Depreciation Calculator NZ 2026

Quick answer Straight-line claims the same percentage of cost every year; diminishing value claims a higher percentage of the remaining book value, so more up front. The rate is set by IRD per asset class, and this shows both methods side by side over the asset's life. On this page's worked example, an asset costing $1,050,000 with a $100,000 salvage value over 25 years writes off $38,000 a year in a straight line, while diminishing value front-loads the same total.

Our Depreciation Calculator is designed to help you accurately calculate the loss of value of an asset over a set period of time. Depreciation is an essential factor in financial planning, tax reporting, and business accounting, as it helps determine the declining value of an asset and how it affects overall financial performance. This tool allows you to calculate depreciation using two widely used methods: the Straight Line Depreciation Method and the Diminishing Balance Depreciation Method, each providing different insights into how an asset depreciates over its useful life. The Straight Line Depreciation Method is the simplest way to calculate depreciation, spreading the asset’s value evenly over its estimated lifespan. This method assumes that the asset loses value at a consistent rate each year, making it a common choice for businesses and individuals looking for a straightforward way to account for asset depreciation. With this method, you can determine the annual depreciation expense, the total depreciation over the asset’s lifespan, and the book value of the asset after a specified number of years. The Diminishing Balance Depreciation Method, also known as the declining balance method, assumes that an asset loses more of its value in the earlier years of its useful life. This method is often used for assets that rapidly decline in value, such as vehicles, machinery, and technology equipment. The calculator will generate a depreciation amortisation table, showing the asset's book value at the end of each year until it reaches the estimated salvage value. This approach provides a more realistic view of depreciation for assets that experience higher wear and tear in their initial years. Both depreciation methods consider the total cost of the asset, including additional costs such as transport, insurance, and installation. The calculator also factors in the asset salvage value, which is the estimated book value of the asset after it has fully depreciated. If the asset has no residual value at the end of its useful life, the salvage value can be set to zero. This calculator is an essential tool for businesses, accountants, and individuals who need to manage depreciation for financial planning, asset management, and tax purposes. By understanding how an asset depreciates, you can make informed decisions about investments, replacements, and financial forecasting. Try the Depreciation Calculator today to get an accurate assessment of your asset’s value over time.

Calculate.co.nz is proud to be partnered with realtor.co.nz, a trusted resource for navigating the New Zealand property market. Their Helpful Articles section offers clear, well-structured insights across buying, selling, and building, making complex real estate topics more accessible. With a focus on up-to-date guidance and practical knowledge, they empower Kiwis to move forward with clarity and confidence in a constantly evolving property landscape.
Calculate.co.nz partner: realtor.co.nz
Advertise on this page

Straight Line Depreciation Method

$
$
$
$
years
%
$
$
$

Diminishing Balance Depreciation Method

$
$
$
$
years
%

Diminishing Balance Depreciation Method Depreciation Schedule


How it works

Straight line depreciation spreads the depreciable amount, the total asset cost minus its salvage value, evenly across its useful life: annual depreciation equals (total cost minus salvage value) divided by useful life in years. Diminishing balance depreciation instead applies a fixed percentage to the asset's remaining book value each year, so the deduction is largest in the early years and shrinks over time as the book value falls toward the salvage value. Both methods use the same total cost (initial cost plus additional costs such as delivery or installation) and the same salvage value as their starting point; they only differ in how that depreciable amount is spread across the years.

Worked example

An asset with a total cost of $1,050,000 (an initial cost of $1,000,000 plus $50,000 of additional costs), a salvage value of $100,000 and a 25 year useful life depreciates by (1,050,000 minus 100,000) divided by 25, or $38,000, each year under the straight line method. That is a straight line rate of 3.62% of total cost per year. After 10 years the accumulated depreciation is $380,000, leaving a book value of $670,000.

The same asset under the diminishing balance method uses a rate of 8.98% per year, which is the rate that reduces $1,050,000 down to the $100,000 salvage value over 25 years (1 minus the 25th root of 100,000 divided by 1,050,000). Year one depreciation is $94,255.68, leaving a book value of $955,744.32, and each later year's deduction is 8.98% of the reducing balance rather than a flat amount.

Related calculators

Frequently asked questions

What is the Depreciation Calculator NZ 2026?

Calculate asset depreciation using straight-line or diminishing value methods. Enter asset cost, residual value, and useful life to see annual depreciation and a full depreciation schedule.

Is the Depreciation Calculator NZ 2026 free to use?

Yes. The Depreciation Calculator NZ 2026 is free to use on Calculate.co.nz, with no sign-up, paywall or account required.

Is the Depreciation Calculator NZ 2026 made for New Zealand?

Yes. It is built for New Zealand and uses current New Zealand rules and rates where they apply. Results are indicative estimates and not financial advice.