Can I claim? Yes. Conditions If you have a mobile phone or number strictly for business use, then of course you can offset all phone costs against the business (1).  However, if you use the phone for both business and private use (like many freelancers) then only the percentage used for the business can be allocated (2). On SimpleTax (1) Self-Employed expenses: Office Space & Utilities - Phone & Fax (2) Self-Employed expenses: Use of Home as Office - Phone & Fax *** More information No business is complete without a phone, whether it is desk-based or a mobile. Only business related communications can be set against your income, any private use should be entirely excluded from any bills. As a freelancer you should be able to express the private use percentage or amount to keep track of your business accounts. You can claim each phone expenditure, without its private usage percentage, separately OR you can go instead with the HMRC’s flat rates for using your phone for business use.  Flat rates apply a standard value per week for the total “home as office” expenditure including rent and utilities. Flat rates on SimpleTax SimpleTax will do all of the work for you and allocate your flat rates as follows: If you have calculated your flat rates you can enter the amount under Self-Employed expenses: Use of home as office (or) Office Space & Utilities – Other     other keywords: cell, telephone, digital, iphone, carrier,