Yes — you can claim the work-related proportion of your personal mobile phone costs as a tax deduction. If you use your phone to make work calls, access work emails, use work apps, or any other employment-related purpose, that portion of your phone bill is deductible. You need a 4-week usage diary to substantiate the claim.
What Qualifies
Deductible phone use includes:
- Work calls (to clients, colleagues, managers)
- Work-related data use (accessing work email, systems, apps, messaging platforms)
- Work-related apps and subscriptions on the phone
Only the work proportion is deductible — personal calls, streaming, social media, and personal browsing are private.
How to Work Out the Work Proportion
The ATO accepts a 4-week representative diary to establish the percentage:
- For four representative weeks, log your calls — work vs personal minutes
- Log your data use — work-related data vs personal data
- Calculate the percentage for each
- Blend or apply to your annual phone costs
Keep your phone bills for the period as supporting evidence.
Example:
- 30% of calls by duration were for work
- 15% of data was for work
- Blended estimate: 20% work use
- Annual plan cost: $900
- Deduction: $180
Can I Claim a New Phone?
If you purchase a phone:
- Under $300, primarily for work: Claim the work proportion in full in the year of purchase
- $300 or more: Depreciate over 3 years at the work-use proportion
Example: $1,100 phone, 50% work use → $1,100 × 50% ÷ 3 years = $183/year
What You Cannot Claim
- Phone costs if your employer already reimburses them or provides a work phone
- Personal calls and data — only the work proportion
- Phone-related accessories for personal use
WFH Fixed Rate Users — Important
If you are using the 67c/hour WFH fixed rate, your mobile phone and home internet costs for WFH purposes are already included in the rate. Do not separately claim them.
However, phone calls made for work when you are out of the home office (e.g., at a client site, on the road) are not part of the WFH rate and can be claimed separately.
Frequently Asked Questions
Do I need to keep 4 weeks of phone records every year? You only need a new 4-week diary if your work-use pattern changes significantly from the prior year. If your job and phone habits are consistent, the same proportion can be applied in subsequent years without a new diary — though it is good practice to refresh it every 2–3 years.
My employer gave me a work phone but I use my personal phone for backup work calls. Can I claim? Yes — if you use your personal phone for work beyond what the employer provides, the personal phone’s work use is deductible.
I am self-employed and use my phone almost entirely for work. Can I claim most of it? Yes — if your records show high work use (e.g., 80–90%), that proportion is deductible. The key is that the diary reflects actual usage and the proportion is genuine.
This article provides general tax information. For advice tailored to your situation, speak with a registered tax agent. Find one through the Tax Practitioners Board register.