If you’re self-employed, your business will have various running costs. You can deduct some of these costs to work out your taxable profit as long as they’re allowable expenses. Doing this will decrease the amount of tax you have to pay. Allowable expenses don’t include money taken from your business to pay for private purchases. Costs you can claim as allowable expenses. These include; Office costs, eg stationery or phone bills, Travel costs, eg fuel, parking, train fare Clothing expenses, e.g. uniforms, Staff costs, eg salaries, outsourcing costs, Things you buy to sell on Financial costs, eg insurance or bank charges, Costs of your business premises, Advertising or marketing, eg website costs. Contact the Self Assessment helpline if you’re not sure whether a business cost is an allowable expense on 0300 200 3310.
Costs you can claim as capital allowances
If you use traditional accounting, claim capital allowances when you buy something you keep to use in your business, eg: Equipment or Machinery or Business vehicles. If you use something for both business and personal reasons, you can only claim allowable expenses for the business costs. For example, your mobile phone bills for the year total £200. Of this, you spend £130 on personal calls and £70 on business. You can claim for £70 of business expenses. If you work from home, you may be able to claim a proportion of your costs for things like: heating, electricity, council Tax, mortgage interest or rent, internet and telephone use. You’ll need to find a reasonable method of dividing your costs, eg by the number of rooms you use for business or the amount of time you spend working from home. If you have 4 rooms in your home, one of which you use only as an office. Divide them by 4.
www.gov.uk/expenses-if-youre-self-employed