Mobile Phone Costs — United Kingdom Tax Rules

Claim the business-use proportion of your mobile phone handset and monthly contract.

Claimable: Partially claimable · Tax authority: HMRC

HMRC Rules

• You can claim the business-use percentage of your phone contract and handset cost.
• Estimate the proportion of calls, texts, and data used for business versus personal use.
• A phone used 100% for business can be claimed in full — but HMRC will question this unless you have a separate personal device.
• If you have a separate business SIM or phone line, claim 100% of that cost.
• The same apportionment principle applies to phone accessories (case, screen protector) used for business.
• VoIP subscriptions (Vonage, RingCentral) used for business calls are fully deductible as office costs.

Limits

No fixed cap — claim must reflect genuine business-use proportion. Typical claims range from 40% to 80% of total phone costs.

Worked Example

Tom estimates he uses his phone 60% for business. His annual contract is £600 and the handset cost £800. He claims £600 × 60% = £360 for the contract and £800 × 60% = £480 for the handset = £840 total. He records the 60% estimate in his records with a note on how he arrived at it.

Record Keeping

• Keep phone bills and purchase receipts
• Document your estimated business-use percentage with reasoning
• Consider reviewing call logs periodically to support your estimate
• If using a separate business phone, keep it clearly separated in records
• For handset costs, note the date of purchase and claimed proportion

Frequently Asked Questions

Can I claim 100% of my phone if I use it mostly for business?

Only if you use it exclusively for business with zero personal use. HMRC will challenge a 100% claim on a single phone unless you have a separate personal device. In practice, most sole traders claim 50–80% and document their reasoning.

What about phone apps and cloud storage used for business?

Yes. Business software subscriptions accessed via your phone (accounting apps, project management tools, cloud storage) are fully deductible as office costs if used exclusively for work — or proportioned for mixed use.

Is a second SIM card for business fully claimable?

Yes. A dedicated business SIM used only for work calls and data is 100% deductible. Keep the monthly bills as evidence and ensure it is separate from your personal SIM.

Can I claim the cost of a phone bought outright rather than on contract?

Yes. A phone purchased outright is treated as a capital item — claim it via the Annual Investment Allowance at the business-use proportion. Under cash basis accounting (most sole traders under £150,000), you can simply expense the proportional cost directly.