Hi, (I've tried to search for an answer here, this must have been asked before so if anyone wants to point me to a link or two please do) I'm trying to work out how to account for my mobile tariff as a self-employed person. I have a personal Vodafone contract with unlimited everything, and due to location/access, I currently use it 5 working days a week, all day, as my access point. It's also used for business calls. Numerous apps on it are used for work. I'm a Web Developer so it's also used for some mobile testing. Outside of work, it's used for everything a smartphone is used for these days. If I had to estimate the usage breakdown, I'd say it's used about 40% of the time for business. The contract is around £60 a month. I believe that the conventional wisdom / guidance is: If a personal phone contact is used for work, only the cost of the actual work calls can be offset against tax. This doesn't apply for me, I have all data, minutes, texts etc bundled in the £60. Any advice please?