Every SAP S/4HANA Public Cloud project has four technical scope dimensions that must be explicitly defined, documented, and signed off before the Prepare phase begins. Each one has a direct cost implication. Leave any one undefined and your project inherits a scope risk that surfaces expensively in Realize phase.
Dimension 1: Custom Code Scope
Your existing custom ABAP objects must be classified into four categories using SAP Readiness Check and the Custom Code Migration Tool (CCMT): Retire (already covered by standard S/4HANA), Replace (addressable by SAP Best Practice configuration), Rebuild as a BTP side-by-side extension, or Redesign via process change. The Rebuild category is the scope driver, each object requires development effort and adds to BTP consumption cost.
Dimension 2: Integration Scope
Every RFC, BAPI, IDoc, and middleware connection must be inventoried and classified. SAP Integration Suite provides pre-built packages for common SAP-to-SAP and SAP-to-third-party scenarios, these are configuration effort. Custom integrations require development effort. The classification between the two determines your integration architecture budget and timeline.
Dimension 3: Data Migration Scope
Define exactly which master data objects (CoA, cost centers, vendors, customers, materials) and open item types (open POs, open SOs, open FI items) will be migrated using SAP Migration Cockpit. Before estimating effort, run a source data quality assessment. Every data quality issue found late extends the go-live date. Data quality is a business problem, not a technical one and it must be owned by business data owners before migration effort can be reliably estimated.
Dimension 4: Process Scope
Define which SAP S/4HANA Public Cloud process modules are in scope for the initial go-live and which are explicitly deferred to Phase 2. Phased rollouts by module (Finance first, then Procurement, then Supply Chain) reduce Realize sprint complexity and shorten the go-live critical path. The deferred scope must be documented and agreed, not simply excluded and forgotten.
At Byte Sense, we facilitate scoping workshops that define and document all four dimensions with business sign-off on each before the implementation contract is finalized. Our clients enter Prepare with scope, not assumptions. This approach minimizes surprises during implementation, reduces the risk of misalignment between business and system expectations, and creates a stronger foundation for project governance and decision-making. Instead of spending the project correcting gaps discovered too late, teams can focus on execution, adoption, and value realization from day one.
A successful ERP implementation is not defined by how fast the system goes live, but by how clearly the organization understands what is being implemented, why it matters, and how it supports long-term operational goals. The quality of the Prepare phase ultimately determines the stability of everything that follows.