Employees guide for work expenses

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Part B - Apportioning work-related expenses

Keeping a diary

You can claim only the portion of an expense that relates to your work activities. When you incur an expense for a purpose that is not 100% work-related, you can only claim the work-related percentage.

For some deduction items, there is a specific requirement to keep records to apportion your expenses, such as the logbook method for car expenses (see Logbook method ). Otherwise, you need to keep suitable records to show how you have worked out your work-related use. This could take the form of electronic records, data from applications or by keeping a work diary.

Keeping a diary

To help show how you have apportioned your expenses, such as working from home expenses (for example, electricity and internet expenses) and mobile phone expenses, you can keep a detailed diary for a 4-week representative period. This shows the pattern of your usage and the proportion of work to private use, which you can then apply to the rest of the year. You can use a representative period only if your work use proportion is consistent throughout the year. If your usage fluctuates, you will need to keep records for the whole year.

If you are keeping a diary, you should:

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keep it for a continuous 4-week period

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fill it in at the time you undertake the activity, not retrospectively, and

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include sufficient detail to support your calculations.

Where a home office or internet connection isn't just for one person's use, it's important to show other people's usage as well, such as for a home office that is used both for work purposes and as a study area for children.

Example – shared internet connection

Marcus is keeping a diary of his home internet use. On Monday, he works from home and records his internet use from 8:00 am to 12:00 pm and 12:30 pm to 3:00 pm for work purposes. In the afternoon, his children use the internet for schoolwork from 3:30 pm to 5:30 pm. That evening, his family use the internet to stream movies from 6:30 pm to 9:30 pm, and Marcus and his partner browse the internet from 9:30 pm to 10:30 pm.

Marcus records all of these different sessions in his diary and clearly labels them as work-related or private usage. Once he has done this for 4 representative weeks, he can calculate his usage based on either the percentage of time the internet is used for employment activities versus private use or for the amount of data downloaded for each separate use.

Once you have established the proportion of your work and private use over a representative 4-week period, apply this proportion to your working year. Take out any time when you aren't working. For example, if you have a 4-week holiday, you can claim a deduction only for 48 weeks' average usage.

The diary, along with itemised bills from suppliers such as telecommunication companies, will help you identify the usage that relates to your employment activities and your private activities.

Example – mobile phone apportionment

Roz is a full-time real estate agent and uses her personal phone for work. She has a mobile phone plan that costs $60 per month which includes $600 worth of calls and 40 GB of data. She receives a bill which itemises all her phone calls and data usage.

Over the 4-week representative period, Roz makes 428 calls of which she identifies 336 as being for work purposes. Roz decides to work out her work use percentage on the volume of calls rather than the time spent on the calls.

Calls for work purposes

Total work calls ÷ Total number of calls = Work use percentage for calls
336 ÷ 428 = 80%


Roz uses 30 GB of her allocated data and from her bill she estimates that 21 GB is related to her work. She does this by comparing her usage on the bill with her work diary.

Data for work purposes

Total work data use ÷ Total data use = Work use percentage for data
21 ÷ 30 = 70%


Roz takes the average of these to determine her work use percentage.

(Work use percentage for calls + Work use percentage for data) ÷ 2 = Overall work use percentage
(80 + 70) ÷ 2 = 75%


Therefore, Roz can claim 75% of the total bill of $60 for each month she worked as a real estate agent for the same employer.

Total bill for each month × Overall work use percentage = Monthly amount to be claimed
$60 × 75% = $45


As Roz started on 1 April, she claims for the last 3 months of the income year.

Monthly claim amount × Number of months = Total claim amount
$45 × 3 = $135


Roz keeps a record of her bill that shows how she worked out the work-related use of her phone.

For more information, see:

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Law Administration Practice Statement PS LA 2001/6 Verification approaches for electronic device usage expenses .

Amendment history

 

 

 

 

References

Related Rulings/Determinations:
IT 2477
IT 2543
TR 92/15
TR 93/30
TR 94/22
TR 95/25
TR 95/34
TR 96/18
TR 97/7
TR 97/12
TR 97/24
TR 98/5
TR 2000/2
TR 2003/16
TR 2004/6
TR 2020/1
TR 2021/1
TR 2021/4
TR 2024/3
TD 93/114
TD 97/19

Related Practice Statements:
PS LA 1999/2
PS LA 2001/6
PS LA 2005/7

Case References:
AT85/98 and Commissioner of Taxation
[1987] AATA 145

B636/1985 and Commissioner of Taxation
[1986] AATA 318

Case C47; Case 44
71 ATC 219
11 CTBR (NS) 207

Case K2; Case 21
78 ATC 13
22 CTBR (NS) 178

Case No 69/1978
79 ATC 488
23 CTBR (NS) 680

Case No M 99/1981
82 ATC 139
25 CTBR (NS) 696

Case No M 282/1979
81 ATC 383
25 CTBR (NS) 200

Case No M 208/1983
84 ATC 411
27 CTBR (NS) 867

Case Nos M 309/1980, M 216/1981
82 ATC 72
25 CTBR (NS) 608

Case N44; Case 114
81 ATC 216
24 CTBR (NS) 915

Case P31; Case Q17
82 ATC 141
83 ATC 62

Case P114; Case 47
82 ATC 586
26 CTBR (NS) 365

Case R49; Case 104
84 ATC 387
27 CTBR (NS) 836

Case R70; Case 124
84 ATC 493
27 CTBR (NS) 981

Case S82; Case 87
85 ATC 608
28 CTBR (NS) 678

Case T47; Case No 1409/1985
86 ATC 381
29 CTBR (NS) 345

Commissioner of Taxation v Faichney
[1972] HCA 67

Commissioner of Taxation (Cth) v Finn
[1961] HCA 61

Commissioner of Taxation (Cth) v Forsyth
[1981] HCA 15

Commissioner of Taxation (Cth) v Smith
[1981] HCA 10

Commissioner of Taxation (Cth) v Vogt
[1975] 1 NSWLR 194

Commissioner of Taxation (Cth) v Wiener
8 ATR 335

Federal Commissioner of Taxation v Maddalena
71 ATC 4161
2 ATR 541

Frankcom, Terrence James v Commissioner of Taxation
[1982] VicSC 469

Fullerton, L.W. v Commissioner of Taxation
[1991] FCA 702

Handley v Commissioner of Taxation (Cth)
[1981] HCA 16

Lodge v Commissioner of Taxation (Cth)
[1972] HCA 49

Lunney v Commissioner of Taxation
[1958] HCA 5

Morris v Commissioner of Taxation
[2002] FCA 616

NT85/4959 and Commissioner of Taxation
[1987] AATA 575
87 ATC 470

Re Taxation Appeals
[1991] AATA 197

Re Taxation Appeals
[1994] AATA 315

Ronpibon Tin NL and Tongkah Compound NL v Federal Commissioner of Taxation
[1949] HCA 15

Sun Newspapers Limited v Federal Commissioner of Taxation
[1938] HCA 73

ST86/633 and Commissioner of Taxation
[1987] AATA 567
87 ATC 575

ST87/36 and Commissioner of Taxation
[1987] AATA 424

TT 87/8, TT 87/168 and Commissioner of Taxation
[1987] AATA 863

Thomas v Commissioner of Taxation (Cth)
[1972-73] ALR 368

Other References:
Income Tax Assessment (Effective Life of Depreciating Assets) Determination 2025
PCG 2023/1
PCG 2024/2