Converting a basement into a legal secondary suite is one of the most financially compelling projects a Canadian homeowner can undertake — rental income in major cities often covers a significant portion of the mortgage. But a legal suite costs 50–80% more than a standard finished basement of the same size because it must meet an entirely different set of building code requirements: fire-rated separation, a full kitchen, bedroom egress windows, and a separate entrance. In Toronto, a code-compliant 1,000 sq ft unit runs $51,000–$104,000; Vancouver costs run approximately 25% higher.
This calculator is built specifically for secondary suite conversions — not general basement finishing. Configure your suite's square footage, separate entrance type (interior stairwell or exterior foundation cut), kitchen tier, bathroom count, fire separation requirements, electrical panel upgrade, and permit costs for your municipality. The estimate reflects the higher labour and material standards required for a unit that must pass formal inspections in your province.
Before you budget, confirm your property's zoning allows a secondary suite — most Canadian municipalities now permit them by right, but some still require a rezoning application. Pull the permit early: inspectors need access at framing, rough-in, and final stages, and permit timelines often drive the overall project schedule more than construction.