As a business owner, it’s common to have expenses that overlap between business and personal use. The tricky part is figuring out what portion is deductible. Done correctly, this can save you money at tax time. Done incorrectly, it can raise red flags with the tax office. Here are some detailed examples to guide you: Home office costs If you use a dedicated space in your home for work, you can deduct a percentage of household expenses such as rent or mortgage interest, utilit