Working out decline in value

You work out deductions for the decline in value of most depreciating assets, including those acquired before 1 July 2001, under the UCA rules.

The UCA contains general rules for working out the decline in value of a depreciating asset, and those rules are covered in this part of the guide. Transitional rules apply to depreciating assets held before 1 July 2001 so you can work out their decline in value using these rules; see Depreciating assets held before 1 July 2001.

The general rules do not apply to some depreciating assets. The UCA provides specific rules for working out deductions for the assets listed below:

• certain depreciating assets that cost $300 or less and that are used mainly to produce non-business assessable income; see Immediate deduction for certain non-business depreciating assets (costing $300 or less)
• certain depreciating assets that cost or are written down to less than $1,000; see Low-value pools
• in-house software for which expenditure has been allocated to a software development pool; see Software development pools
• depreciating assets used in exploration or prospecting; see Mining and quarrying, and minerals transport
• water facilities, fencing assets, fodder storage assets and horticultural plants (including grapevines); see Primary production depreciating assets
• certain depreciating assets of primary producers, other landholders and rural land irrigation water providers used in landcare operations; see Landcare operations
• certain depreciating assets of primary producers and other landholders used for electricity connections or phone lines; see Electricity connections and phone lines
• trees in a carbon sink forest; see Carbon sink forests.

There are also specific rules for working out notional deductions for depreciating assets used in carrying on research and development activities; see Research and development tax incentive schedule instructions 2018 (NAT 6709).

When does a depreciating asset start to decline in value?

The decline in value of a depreciating asset starts when you first use it, or install it ready for use, for any purpose, including a private purpose. This is known as a depreciating asset’s start time.

Although an asset is treated as declining in value from its start time, a deduction for its decline in value is only allowable to the extent it is used for a taxable purpose; see Definitions.

If you initially use a depreciating asset for a non-taxable purpose, such as for a private purpose, and in later years use it for a taxable purpose, you need to work out the asset’s decline in value from its start time, including the years you used it for a private purpose. You can then work out your deductions for the decline in value of the asset for the years you used it for a taxable purpose; see Decline in value of a depreciating asset used for a non-taxable purpose.

Methods of working out decline in value

You generally have the choice of two methods to work out the decline in value of a depreciating asset: the prime cost method or the diminishing value method. Both the diminishing value and prime cost methods are based on a depreciating asset’s effective life. The rules for working out an asset’s effective life are explained in Effective life of a depreciating asset.

You can generally choose to use either method for each depreciating asset you hold.

Once you have chosen a method for a particular asset, you cannot change to the other method for that asset.

The Depreciation and capital allowances tool will help you with the choice and the calculations.

In some cases, you do not need to make the choice because you can claim an immediate deduction for the asset, for example, certain depreciating assets that cost $300 or less; see Immediate deduction for certain non-business depreciating assets (costing $300 or less).

In other cases, you do not have a choice of which method you use to work out the decline in value. These cases are:

• If you acquire intangible depreciating assets such as in-house software, certain items of intellectual property, spectrum licences, datacasting transmitter licences and telecommunications site access rights, you must use the prime cost method.
• If you acquire a depreciating asset from an associate who has deducted or can deduct amounts for the decline in value of the asset, see Depreciating asset acquired from an associate.
• If you acquire a depreciating asset, but the user of the asset does not change or is an associate of the former user, for example, under sale and leaseback arrangements, see Sale and leaseback arrangements.

If there has been rollover relief, see Rollover relief.

If the asset has been allocated to a low-value pool or software development pool, the decline in value is calculated at a statutory rate, see Software development pools and Low-value pools.

By working out the decline in value you determine the adjustable value of a depreciating asset. A depreciating asset’s adjustable value at a particular time is its cost (first and second elements) less any decline in value up to that time. See The cost of a depreciating asset for information on first and second elements of cost. The opening adjustable value of an asset for an income year is generally the same as its adjustable value at the end of the previous income year.

You calculate the decline in value and adjustable value of a depreciating asset from the asset’s start time independently of your use of the depreciating asset for a taxable purpose. However, your deduction for the decline in value is reduced by the extent that your use of the asset is for a non-taxable purpose; see Decline in value of a depreciating asset used for a non-taxable purpose. Your deduction may also be reduced if the depreciating asset is a leisure facility or boat even though the asset is used, or installed ready for use, for a taxable purpose; see Decline in value of leisure facilities and Decline in value of boats.

The diminishing value method

The diminishing value method:

• assumes the decline in value each income year is a constant percentage of the base value each year, and therefore,
• produces a progressively smaller decline in the item’s value over time.

Did you hold the depreciating asset before 10 May 2006?

• Yes. For depreciating assets you held before 10 May 2006, the formula for the decline in value is:  
  • base value × (days held ÷ 365) × (150% ÷ asset's effective life)
  • Use this formula for any asset you held before 10 May 2006, even if you disposed of it and reacquired it on or after 10 May 2006.
   
• No. For depreciating assets you started to hold on or after 10 May 2006, the formula for the decline in value is:  
  • base value × (days held ÷ 365) × (200% ÷ asset's effective life).
  • Days held can be 366 for a leap year. (see Note)
   

The base value:

• for the income year in which an asset’s start time occurs, is the asset’s cost
• for a later income year, is the asset’s opening adjustable value for that year, plus any amount included in the asset’s second element of cost for that year.

You cannot use the diminishing value method to work out the decline in value of:

• in-house software
• an item of intellectual property (except copyright in a film)
• a spectrum licence
• a datacasting transmitter licence, or
• a telecommunications site access right.

Note: ‘Days held’ is the number of days you held the asset in the income year in which you used it or had it installed ready for use for any purpose.

• If the income year is the one in which the asset’s start time occurs, you work out the days held from its start time.
• If a balancing adjustment event occurs for the asset during the income year (for example, you sell it), you work out the days held up until the day the balancing adjustment event occurred. For information about balancing adjustment events, see What happens if you no longer hold or use a depreciating asset?.

The prime cost method

The prime cost method:

• assumes the value of a depreciating asset decreases constantly over its effective life, and therefore,
• produces a consistent decline in the item’s value over time.

The formula for the annual decline in value using the prime cost method is:

asset's cost × (days held ÷ 365) × (100% ÷ asset's effective life)

Days held can be 366 in a leap year (see Note).

If there has been rollover relief and the transferor used the prime cost method to work out the asset’s decline in value, the transferee should replace the asset’s effective life in the prime cost formula with the asset’s remaining effective life, that is, any period of the asset’s effective life that is yet to elapse when the transferor stopped holding the asset; see Rollover relief.

An adjusted prime cost formula must be used if any of the following occurs:

• you recalculate the effective life of an asset; see Effective life of a depreciating asset
• an amount is included in the second element of an asset’s cost after the income year in which the asset’s start time occurs; see The cost of a depreciating asset
• an asset’s opening adjustable value is reduced by a debt forgiveness amount; see Commercial debt forgiveness
• you reduced the opening adjustable value of a depreciating asset that is the replacement asset for an asset subject to an involuntary disposal; see Involuntary disposal of a depreciating asset
• an asset’s opening adjustable value is modified due to GST increasing or decreasing adjustments, input tax credits for the acquisition or importation of the asset, or input tax credits for amounts included in the second element of cost of an asset; see GST input tax credits, or
• an asset’s opening adjustable value is modified due to forex realisation gains or forex realisation losses; see Foreign currency gains and losses.

You must use the adjusted prime cost formula for the income year in which any of these changes are made (the ‘change year’) and later years. The formula for the decline in value is:

• (opening adjustable value for 2017–18 + any second element of cost amounts for 2017–18) × (days held ÷ 365) x 100% ÷ asset's remaining effective life.

that is

• opening adjustable value for 2017–18

plus

• any second element of cost amounts for 2017–18
• multiplied bydays held (If held for a full income year, 'days held' is 365, 366 for a leap income year.)

divided by

• 365

divided by

• asset's remaining effective life. The asset’s remaining effective life is any period of its effective life that is yet to elapse either  
  • from 1 July 2017, or
  • in the case of roll-over relief, from the day when the balancing adjustment event occurs for the transferor.
   

The prime cost formula must also be adjusted for certain intangible depreciating assets you acquire from a former holder; see Effective life of intangible depreciating assets.

Depreciating assets held before 1 July 2001

To work out the decline in value of depreciating assets you held before 1 July 2001, you generally use the same cost, effective life and method that you were using under the former law.

The undeducted cost of the asset at 30 June 2001 becomes its opening adjustable value at 1 July 2001.

You work out the undeducted cost of the asset under the former depreciation rules. It is the asset’s cost less the depreciation for the asset up to 30 June 2001, assuming that you used it wholly for producing assessable income.

For a spectrum licence, a depreciating asset that is an item of intellectual property and certain depreciating assets used in mining, quarrying or minerals transport, the opening adjustable value at 1 July 2001 is the amount of unrecouped expenditure for the asset at 30 June 2001. These assets do not have an undeducted cost under the former rules.

Special transitional rules apply to plant for which you used accelerated rates of depreciation before 1 July 2001 or could have used accelerated rates had you used the plant, or had it installed ready for use, for producing assessable income before that day. These rules ensure that accelerated rates continue to apply under the UCA.

Accelerated depreciation

For plant acquired between 27 February 1992 and 11.45am (by legal time in the ACT) on 21 September 1999, accelerated rates of depreciation and broadbanding were available. The rates were based on effective life adjusted by a loading of 20% and broadbanded into one of seven rate groups. The loading, together with the broadbanding, produced accelerated rates of depreciation.

Generally, accelerated rates of depreciation have not been available for plant acquired after 11.45am (by legal time in the ACT) on 21 September 1999. To be taken to be plant acquired before that time, the plant must have been:

• acquired under a contract entered into before that time
• constructed, with construction starting before that time, or
• acquired in some other way before that time.

However, small business taxpayers have been able to continue to use accelerated rates for plant acquired after 21 September 1999 but before 1 July 2001 if they met certain conditions when the plant was first used or installed ready for use.

Small business taxpayers have not been able to use accelerated rates of depreciation for assets they:

• started to hold under a contract entered into after 30 June 2001
• constructed, with construction starting after 30 June 2001, or
• started to hold in some other way after 30 June 2001.

You continue to use accelerated rates to work out the decline in value under the UCA if:

• you used accelerated rates of depreciation for an item of plant before 1 July 2001, or
• you could have used accelerated rates had you used the plant, or had you had it installed ready for use, for producing assessable income before that day.

You replace the effective life component in the formula for working out the decline in value with the accelerated rate you were using. See a list of Accelerated rates of depreciation.

Decline in value of a depreciating asset used for a non-taxable purpose

You calculate the decline in value and adjustable value of a depreciating asset from the start time independently of your use of the depreciating asset for a taxable purpose. However, you reduce your deduction for the decline in value by the extent that your use of the asset is for a non-taxable purpose.

If you initially use an asset for a non-taxable purpose, such as for a private purpose, and in later years use it for a taxable purpose, you need to work out the asset’s decline in value from its start time including the years you used it for a private purpose. You can then work out your deductions for the decline in value of the asset for the years you used it for a taxable purpose.

 

Decline in value of leisure facilities

Your deduction for the decline in value of a leisure facility may be reduced even though you use it, or install it ready for use, for a taxable purpose. Your deduction is limited to the extent that:

• the asset’s use is a fringe benefit, or
• the leisure facility is used (or held for use) mainly in the ordinary course of your business of providing leisure facilities for payment, to produce your assessable income in the nature of rents or similar charges, or for your employees’ use or the care of their children.

Decline in value of boats

The total amount you can claim as a deduction for the decline in value of a boat that you use or hold cannot exceed your assessable income from using or holding that boat in 2017–18. If the total amount of your deduction exceeds the relevant assessable income, we reduce the deduction by the amount of the excess.

Exceptions to that reduction are:

• holding a boat as your trading stock
• using a boat (or holding it) mainly for letting it on hire in the ordinary course of a business that you carry on
• using a boat (or holding it) mainly for transporting the public or goods for payment in the ordinary course of a business that you carry on, or
• using a boat for a purpose that is essential to the efficient conduct of a business that you carry on.

Depreciating asset acquired from an associate

If you acquired plant on or after 9 May 2001 or another depreciating asset on or after 1 July 2001 from an associate, such as a relative or partner, and the associate claimed or can claim deductions for the decline in value of the asset, you must use the same method of working out the decline in value that the associate used.

If the associate used the diminishing value method, you must use the same effective life that they used. If they used the prime cost method you must use any remaining period of the effective life used by them.

You must recalculate the effective life of the depreciating asset if the asset’s cost increases by 10% or more in any income year, including the year in which you start to hold it; see How to recalculate effective life.

You can require the associate to tell you the method and effective life they used by serving a notice on them within 60 days after you acquire the asset. Penalties can be imposed if the associate intentionally refuses or fails to comply with the notice.

Sale and leaseback arrangements

If you acquired plant on or after 9 May 2001 or another depreciating asset after 1 July 2001 but the user of the asset does not change or is an associate of the former user, such as under a sale and leaseback arrangement, you must use the same method of working out the decline in value that the former holder used.

If the former holder used the diminishing value method, you must use the effective life that they used. If they used the prime cost method, you must use any remaining period of the effective life used by them. If you cannot readily ascertain the method that the former holder used or if they did not use a method, you must use the diminishing value method. You must use an effective life determined by the Commissioner if you cannot find out the effective life that the former holder used or if they did not use an effective life.

You must recalculate the effective life of the depreciating asset if the asset’s cost increases by 10% or more in any income year, including the year in which you start to hold it; see How to recalculate effective life.