Mortgage prequalification is an initial estimate of borrowing power based on self-reported financial information without credit verification, serving as a budgeting guide. Preapproval involves a detailed review of verified financial documents and a hard credit check, providing a conditional loan commitment. Preapproval carries more weight with sellers, especially in competitive markets, but neither guarantees final mortgage approval. Preapprovals typically last 60-90 days and do not lock in interest rates unless a rate lock option is chosen.