Self-employed people in Canada can deduct reasonable business expenses that were incurred to earn income-things like home office costs, supplies, vehicle expenses, professional fees, and advertising. The key rule is that the expense must be directly connected to your business and reasonable in amount. You'll need to keep receipts and records for everything you claim, and you can't deduct personal expenses or expenses paid with non-business money. The CRA allows you to deduct ongoing costs needed to run your business, but not capital purchases like equipment (those follow different depreciation rules). If you're self-employed, this CRA rule may apply to you regarding which expenses reduce your taxable income: - Home office: A portion of rent, mortgage interest, property tax, utilities, and home insurance based on the percentage of your home used for business - Vehicle and travel: Gas, maintenance, insurance, and registration for business-related driving (keep a mileage log) - Supplies and materials: Office supplies, software subscriptions, website hosting, and industry-specific materials - Professional services: Accounting fees, legal advice, bookkeeping, and consulting costs related to your business - Advertising and marketing: Website design, social media ads, business cards, and promotional materials - Equipment and tools: Under $500 items like chairs,