Your profile drives CPP/OAS/GIS calculations. Key inputs: birth year determines age and time to retirement; years in Canada after age 18 determines OAS entitlement; CPP contribution years and average earnings percentage determine your CPP amount. For accurate numbers, use the CPP and OAS override fields with amounts from your My Service Canada Account statement — the calculated estimates can differ from reality because Service Canada uses dropout provisions (excludes lowest-earning years), child-rearing provisions, and your actual earnings history.