Your friend and you can split the cost of your trip expenses in several ways including: Equal split, Proportional split, personal Split. A taxpayer may deduct business travel expenses IF they are ordinary and necessary and IF they are incurred away from his or her tax home.If your friends or family travel with you, none of their expenses are deductible. In situations where an individual is conducting business with one or more guests, reasonable meals and entertainment expenses are allowable. The IRS has a specific definition for business travel when it comes to determining whether these expenses are tax deductible. Business travel expenses are tax deductible (for the most part), meaning you could lower the taxes you need to pay. A dedicated travel management system can speed up planning and approvals while streamlining expense data management. Those actual expenses? They're the real MVPs in the deduction game. How to calculate deductible travel expenses?