Phone, fax, email and internet: what you can claim

Most sole traders run their business from a phone that also hosts the family group chat. HMRC knows this, so the rule is simple: a dedicated business line or connection can be claimed in full, and a shared one only for an honest business share.

What you can claim

• A dedicated business phone line or second mobile — line rental, calls and data in full.
• The business share of a shared mobile — worked out from an itemised bill.
• Business broadband — in full if it's separate, or the business share of the home connection.
• VoIP numbers and virtual switchboards — internet phone services for the business.
• Business email — domain registration and email hosting.
• Call forwarding and second-SIM costs — keeping a business number live.
• Roaming charges on business trips — the work-related part of your bill.
• A fax line — some medical, legal and trade suppliers still insist on them.

What you can't claim

• The whole family plan — your partner's and children's lines are not business costs.
• Personal calls and data — the non-business share of every bill.
• Broadband claimed twice — here and again under Use of home. Pick one place.
• A handset bought outright — a new phone is equipment, not a monthly service.
• TV and streaming subscriptions — however much you research your trade while watching.

Common mistakes

Claiming 100% of a phone that is clearly also personal is the fastest way to lose the whole deduction in an enquiry. Keep your itemised bills, mark the business calls, and work out a percentage you can defend — a note like "30% business, based on October's bill" turns a guess into evidence.

Double counting broadband runs a close second. If your Use of home calculation already includes a share of the broadband, don't claim it again here. Each quarterly total should be built from costs that appear once, and once only.

Finally, small recurring costs go missing. A £7-a-month second SIM and a £12-a-year domain renewal add up quietly — sweep through the bank statement each quarter and catch them.

How to record it in your MTD tracker

Select Phone, fax, email and internet and record the bill total with the business percentage in the notes — for example, "£32 mobile, 40% business = £12.80". Log it monthly so the quarterly update builds itself.