Phone and internet costs

Partial

If you have a dedicated business phone or SIM, the full cost is deductible. If you use a personal phone for both work and personal calls, only the business-use proportion is claimable. Estimate the percentage from your call logs or usage. Broadband used partly for work can be claimed on the same proportionate basis.

Common questions

I use my personal mobile for business calls. Can I claim the bill?

Only the business-use proportion. Estimate what percentage of your calls are work-related and claim that fraction of the monthly bill.

I have a separate SIM just for work. Can I claim it?

Yes, in full. A dedicated business line is 100% deductible.

Watch out for

—Keep a sample of call logs to justify any estimated business-use percentage if HMRC asks.

HMRC sources

https://www.gov.uk/expenses-if-youre-self-employed

Last verified: April 2026 · Tax year 2026/27

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This guidance is for general information only. Tax rules change. Verify with HMRC or a qualified accountant before filing.