Choosing the right cloud platform depends on your workload type, existing technology stack, and budget. AWS leads in breadth of services and global reach. Azure is ideal for Microsoft-heavy environments with Active Directory integration. GCP excels in data analytics and Kubernetes workloads with Anthos. This guide covers the 6 R's of cloud migration (Rehost, Replatform, Repurchase, Refactor, Retire, Retain), total cost of ownership calculations, and a practical migration timeline based on our 500,000+ service engagements.