The cost of building a custom home in Ontario ranges from $500 to $1,000 per square foot, depending on factors like location, design, and materials. In cities like Toronto or Vancouver, a typical custom home could cost between $750,000 and $1.5 million, while in smaller markets like Halifax, it may range from $320,000 to $640,000. Costs are influenced by land value, property characteristics, architectural style, and amenities. Additional expenses include zoning and building permits (around $20,000 in Toronto) and potential unforeseen challenges. Hiring an experienced homebuilder with good communication and organization is essential to avoid costly delays and mistakes.