Think about everything you do on your phone in a working day. You answer customer calls, reply to WhatsApp messages, send quotes, manage appointments, take job photos, navigate to sites and even take payments. Which leads to one of the most common questions sole traders ask: can I claim my mobile phone as a business expense?
The short answer is usually yes. The longer answer is slightly more interesting.
HMRC’s Golden Rule
When deciding whether something can be claimed, HMRC generally asks one simple question: was the expense incurred wholly and exclusively for business purposes?
For most sole traders, a mobile phone is used for both business and personal reasons. That means you usually cannot claim the entire bill — unless the phone is genuinely used only for business.
If You Have a Dedicated Business Phone
This is the easiest situation. If you have a separate business handset, a separate business contract and no significant personal use, then the costs are generally straightforward business expenses. That may include:
- monthly contract charges
- the cost of the handset
- business-related apps
- call charges
If You Use One Phone for Everything
This is far more common. Many sole traders use a single phone for business calls, personal calls, customer messaging and family communication all at once.
In this situation, you can normally claim the business proportion of the cost. For example, if you estimate 70% business use and 30% personal use, then only the 70% business element would usually be claimed. The important thing is that the percentage should be reasonable and something you could support if asked.
What About WhatsApp?
This is increasingly relevant. Many sole traders effectively run their business through WhatsApp — customer enquiries, job photos, quotes, updates and payment confirmations all flow through it.
If your phone is central to managing work, that strengthens the argument that a significant portion of the costs relate to business activity.
The Mistake Most People Make
The biggest problem is not overclaiming. It is underclaiming.
Thousands of sole traders never claim anything because they assume “it’s my personal phone”, “HMRC won’t allow it” or “it isn’t worth the hassle”. The reality is that business use of a personal phone is extremely common, and quietly leaving it unclaimed means paying tax on profit you never really made.
The Bottom Line
For most sole traders, mobile phone costs are a legitimate business expense. The key question is not whether you use your phone for work — it is how much of that use relates to business.
Keeping a reasonable estimate and a few good records is all it usually takes. 123Tax helps you log expenses like this as you go, so a fair share of your phone bill is captured throughout the year rather than forgotten by the time your tax return is due.