Allowable expenses are the essential business costs you can subtract from your income before working out how much tax you owe. These include things like office rent, internet bills, professional insurance, business travel, and even a portion of your home bills if you work from home.
The key is that the expense must be “wholly and exclusively” for business. Trying to claim for your weekly shop or that holiday in Marbella? HMRC will raise an eyebrow. Keep your receipts and stick to genuine business costs, and you’ll stay on the right side of the rules.