Can I claim my phone bill as a business expense?

Whether you can claim your phone bill as a business expense depends on who owns the contract, how the phone is used, and whether you operate through a limited company or as a sole trader.

For limited company directors, the most tax-efficient approach is for the company itself to contract directly with the mobile network operator. If the company holds the contract and pays the bill, the cost is a deductible business expense for Corporation Tax purposes. You as the director can use the phone for both business and personal purposes without triggering a benefit in kind, provided that private use is not significant. HMRC accepts that a mobile phone provided by a company to an employee or director is exempt from benefit in kind rules under the specific mobile phone exemption, as long as only one phone per person is provided under this exemption.

This means a director whose company pays for one mobile phone under a company contract has the full cost deducted against Corporation Tax, pays no benefit in kind tax personally, and does not need to report the phone on a P11D. The private use element is irrelevant for this exemption, which is unusually generous.

If you pay for the phone personally using a personal contract and then claim reimbursement from the company, the position is more complex. The company can reimburse you, but only for the business-use proportion. If you use the phone 60% for business and 40% personally, only 60% of the bill can be reimbursed tax-free. The remaining 40% would technically be a benefit in kind if reimbursed in full.

For sole traders, you can claim the business proportion of your phone bill as an expense on your Self Assessment return. To do this, estimate your business usage as a percentage of total usage. For example, if roughly 70% of your calls, texts, and data usage is for business, you can claim 70% of the annual bill. Factors to consider include the number of calls made to clients versus personal contacts, data usage for work versus personal browsing, and whether you have a second phone purely for personal use.

Keeping your business and personal communications on separate devices or separate SIMs makes the accounting clean and any HMRC enquiry straightforward. If you have a personal SIM and a company SIM in one handset, you can claim 100% of the company SIM cost through the company.

For landlines in a home office, the same principle applies. If you have a dedicated business landline, the full cost is deductible. If you use a home landline for both personal and business calls, only the business proportion is deductible.

Internet costs follow a similar logic. If you have a dedicated business broadband line, the full cost is deductible. If you use home broadband for both personal and business use, estimate the business proportion. The HMRC guidance suggests that if the broadband would have been subscribed to anyway for personal reasons, you can only claim the additional cost attributable to business use, which in practice means the business proportion of the total cost.

For company-owned hardware such as handsets, the cost of purchasing a phone is a capital expense and can be claimed through the Annual Investment Allowance, giving 100% deduction in the year of purchase for the business use portion.

Keep your phone bills, and if you use a split approach, keep a note of how you calculated the business percentage. A consistent, documented methodology is more robust than an undocumented estimate if HMRC asks questions.