SAP S/4HANA Readiness Assessment: What to Check Before You Start

If your team has spent the last six months running SAP's Readiness Check 2.0 and calling it an assessment, you are not ready to migrate.

A tool that scans your system and outputs a compatibility report is a starting point - not a strategy. An S/4HANA readiness assessment in 2026 is a structured discovery of every architectural decision you will live with for the next fifteen years. It tells you whether your custom code estate is a migration asset or a liability, whether your integration layer is built for S/4HANA's event-driven model or against it, and whether the architecture you are planning today can actually consume SAP Business AI on day one.

The 2027 SAP ECC end-of-mainstream-maintenance deadline is not a distant concern. It is a capacity constraint. SI partners, hyperscalers, and migration tooling vendors are already experiencing queue pressure. Organizations that begin a structured readiness assessment now will control their migration timeline. Those that delay will inherit whatever schedule and partner availability the market offers them.

This checklist is built for the VP of IT who needs to present a defensible, risk-mitigated migration roadmap to a CIO or board - not a PowerPoint built on optimism.

Why a 2026 S/4HANA Readiness Assessment Is Non-Negotiable

Bottom line: The 2027 deadline is a people and capacity problem as much as a technology problem. Starting a readiness assessment in 2026 is the difference between a migration you design and a migration you react to.

Gartner projects that by 2027, 70% of large enterprise ERP migrations will experience severe budget overruns due to unmitigated technical debt discovered too late in the process. That finding points to a consistent failure pattern: organizations underestimate landscape complexity at the scoping phase, make commitments to the board based on that underestimate, and spend the back half of the project absorbing cost overruns they were not equipped to fund or explain.

The readiness assessment exists to prevent that sequence. Done well, it produces four outputs that no automated tool can generate:

• A prioritized custom code remediation or retirement list with estimated effort per object
• An integration map showing which third-party connections require re-platforming to SAP BTP
• A data quality and volume summary that determines migration wave structure
• A Clean Core conformance baseline that sets the architectural standard for the project

These four outputs are the foundation of a credible migration business case. Without them, every timeline and budget estimate carries risk that your board has not been told to price in.

The resource bottleneck is real. Migration partners with deep S/4HANA architecture experience are operating with reduced availability as 2027 approaches. An organization that has completed a thorough assessment will be a more attractive and better-prepared client to those partners - and will start the project at a faster cadence because the discovery work is already done.

Check 1: Custom Code Remediation and the Clean Core Strategy

Bottom line: Over 80% of SAP customers have custom code that requires remediation or retirement before migrating to S/4HANA. The assessment determines which code goes forward, which gets retired, and which moves to SAP BTP - a distinction that shapes your entire project budget.

Custom code is the single highest-risk variable in any S/4HANA migration. The question is not whether you have it - nearly every organization running SAP ECC does. The question is whether your assessment gives you a clear, object-level view of what that code does, whether it is still needed, and what it will take to make it S/4HANA-compatible.

SAP's Readiness Check 2.0 and the custom code compatibility tool (SCMT) will produce an output. What they will not do is tell you whether that custom code is serving a business purpose that S/4HANA's standard functionality now covers natively. That gap is where migration budgets get misallocated.

A well-run custom code audit during the assessment phase should answer three questions for every significant custom object:

Retire or replace with standard. S/4HANA 2023 and 2025 releases introduced significant expansions to standard financial, procurement, and supply chain functionality. A material percentage of legacy ABAP code - particularly around reporting, pricing logic, and workflow - can be retired entirely if the assessment maps those objects against current S/4HANA standard capabilities.

Remediate in core. Code that represents genuine differentiation or fills a legitimate functionality gap that SAP does not address may remain in core - but must be refactored to use public SAP APIs rather than direct table reads or deprecated function modules. This is the foundation of Clean Core compliance.

Move to SAP BTP. Code that represents true competitive differentiation but does not need to live inside the S/4HANA system should be re-platformed to SAP Business Technology Platform using the SAP Extension Suite. This approach maintains Clean Core integrity while preserving the business logic your teams depend on.

The ABAP Test Cockpit (ATC) and the custom code migration app should be standard tooling in this phase. But the strategic decisions around retire, remediate, or move require human judgment against business process context - which is why automated tool output without architectural interpretation is insufficient.

ITChamps leverages its proprietary 3PS framework to deliver S/4HANA readiness assessments that include structured custom code remediation path identification and Clean Core architecture alignment at the object level. The output is not a compatibility list. It is a prioritized work plan.

Organizations adopting a Clean Core strategy during their assessment phase reduce ongoing maintenance costs by up to 30% post-migration, according to ASUG and LeanIX research. That figure reflects reduced upgrade effort, reduced regression testing scope, and reduced dependency on specialized ABAP resources for every subsequent SAP release.

Check 2: Business Process Alignment and SAP Fiori Optimization

Bottom line: Migrating to S/4HANA without reassessing your business processes means lifting your existing inefficiencies into a new system at significant cost. The assessment is your best opportunity to identify what to simplify.

S/4HANA is not a technical upgrade of ECC. Its data model is fundamentally different - the Universal Journal replaces the fragmented table structure of FI, CO, and EC, and similar consolidations apply across MM, SD, and PP. If your current processes were designed around ECC's data architecture, those processes may be creating unnecessary complexity in an S/4HANA context.

The business process layer of the assessment should identify three categories:

Processes that S/4HANA handles natively and better than your current custom or workaround approach. These should be mapped to standard Fiori applications and the custom code removed.

Processes where S/4HANA's standard functionality is a close match but requires configuration. These should be documented as configuration objects, not development items, to maintain Clean Core posture.

Processes that are genuinely unique to your organization's operating model and require extension or development. These are the candidates for SAP BTP extensibility.

Identifying Process Consolidation Opportunities

The S/4HANA migration is the single most disruptive change your ERP landscape will undergo in a decade. The assessment phase is the correct time to challenge processes that have accumulated complexity through years of workarounds, organizational changes, and bolt-on customization.

Process consolidation opportunities that go unidentified during the assessment become technical debt in the new system. Engage your business process owners during the assessment - not after the blueprint phase has closed.

Change Management and User Adoption Impacts

The shift from ECC's SAP GUI transaction model to S/4HANA's Fiori-based experience is not a minor UX change for the users who run your day-to-day operations. The assessment should include a user role and authorization review that maps current SAP GUI roles to Fiori application groups.

Under-estimating the change management scope is a common source of go-live delays. Identify your highest-impact user populations during the assessment and build adoption planning into the project timeline from the start.

Check 3: Integration Architecture and SAP BTP Readiness

Bottom line: Every point-to-point integration your ECC landscape has accumulated is a project risk in an S/4HANA migration. The assessment must produce a full integration inventory before a project timeline is ever proposed.

SAP ECC systems that have been in production for ten or more years routinely carry integration sprawl - third-party connections, EDI mappings, middleware configurations, and API calls that were built as individual responses to business needs rather than as part of a coherent integration architecture.

S/4HANA's API-first design and SAP Integration Suite on BTP provide a modern foundation for integrating third-party systems. But that foundation is only valuable if your assessment accurately scopes what needs to be connected to it.

The integration layer of the assessment should produce:

An inventory of every inbound and outbound interface, including middleware layers (SAP PI/PO, third-party ESBs, custom SOAP/REST endpoints) and file-based transfers.

A classification of each interface by business criticality and migration complexity. Interfaces that are low-criticality and high-complexity are candidates for retirement. High-criticality interfaces should be re-platformed to SAP Integration Suite to eliminate middleware technical debt.

An assessment of SAP PI/PO dependency. SAP PI/PO reaches end of mainstream maintenance in 2027 on the same timeline as ECC. Organizations running PI/PO as their integration middleware should plan to migrate to SAP Integration Suite as part of the S/4HANA project - not as a subsequent initiative.

As an SAP Gold Partner, ITChamps aligns assessment outcomes with SAP BTP architecture and SAP Business AI capabilities, ensuring that integration re-platforming decisions are made within the context of the broader cloud and AI strategy - not in isolation.

Check 4: Data Volume Management and Archiving Strategy

Bottom line: Migrating thirty years of ECC data to S/4HANA is not a requirement. The assessment determines what data needs to move, what can be archived, and what the migration wave structure should be to minimize downtime risk.

HANA's in-memory architecture performs differently from the traditional disk-based databases that underpin most ECC installations. Data volume directly affects system sizing, licensing costs under RISE with SAP, and migration execution time.

The data management layer of the assessment should cover:

Data archiving and decommissioning. Legacy data that is required for regulatory or audit purposes but not needed for active operations should be archived to a compliant third-party data store rather than migrated. SAP Information Lifecycle Management (ILM) and third-party archiving tools should be evaluated during the assessment.

Data quality assessment. Migrating poor-quality master data - duplicate vendor records, incomplete customer hierarchies, inconsistent material data - recreates those problems in the new system at the cost of significant migration effort. A data quality audit during the assessment phase prevents a data cleansing project from appearing on the critical path mid-migration.

Migration wave design. For large landscapes, a single-wave cutover to S/4HANA may not be feasible. The data volume assessment should inform a wave design that sequences migration by business unit, geography, or data domain to manage downtime windows and parallel run complexity.

Data volume and quality decisions made during the assessment directly determine whether your migration can be executed in a planned maintenance window or requires an extended cutover with significant business disruption.

Check 5: Cloud Hosting Model (RISE with SAP vs. Private Cloud)

Bottom line: RISE with SAP is not the right answer for every organization. The assessment must evaluate your technical requirements, operational model, and long-term cloud strategy before a hosting decision is locked.

RISE with SAP packages S/4HANA Cloud Private Edition with managed infrastructure, SAP Business Network access, and embedded BTP entitlements into a subscription model. For many organizations - particularly those with limited SAP Basis capacity or a strategic preference for OpEx over CapEx - it is a strong fit.

But RISE with SAP is not universally optimal. Organizations with significant customization requirements, specific data residency obligations, or existing hyperscaler commitments under an enterprise agreement should assess the full spectrum of options before committing.

The hosting assessment should evaluate:

RISE with SAP. Total cost of ownership over a five-year period, including the value of included BTP entitlements, managed infrastructure, and reduced Basis headcount requirement.

S/4HANA Cloud Private Edition on a hyperscaler (non-RISE). Applicable if your organization has existing Azure, AWS, or GCP enterprise agreements with committed spend that can absorb S/4HANA infrastructure - and if you have the Basis capability to manage the infrastructure layer.

On-premise or private cloud. Still applicable in specific regulated industries or where data sovereignty requirements make public cloud hosting complex. Should be evaluated with a full understanding of the 2027 maintenance constraint.

The hosting model decision affects licensing structure, infrastructure cost, Basis team requirements, upgrade cadence, and BTP entitlement scope. It should be made during the assessment phase - not during project execution.

Check 6: SAP Business AI and Joule Readiness

Bottom line: The S/4HANA architecture you are designing today is the foundation for SAP Business AI adoption tomorrow. The assessment must confirm that your planned architecture does not block AI capability access at go-live.

SAP Business AI is embedded across S/4HANA 2023 and 2025 releases - in financial close, procurement, supply chain planning, and HR. Joule, SAP's generative AI copilot, is being extended across the S/4HANA Fiori landscape. These capabilities are not add-ons. They are embedded in the application layer and activated through the SAP BTP AI Core service.

The AI readiness layer of the assessment should confirm:

Clean Core compliance is a prerequisite, not a future state. AI features that interact with S/4HANA data models depend on those models conforming to SAP's standard API surface. Custom code that reads tables directly, bypasses standard business objects, or modifies core data structures can block AI feature activation. Clean Core is not just an architectural preference - it is the technical condition for consuming embedded AI.

BTP service entitlements are scoped correctly. AI Core, AI Launchpad, and the Generative AI Hub are BTP services. The assessment should confirm that your planned BTP entitlement structure includes the services required for your target AI use cases.

Data quality supports AI inference. SAP's embedded AI features perform on the quality of the data they operate against. A financial close assistant that runs on inconsistent chart-of-accounts data, or a demand sensing model built on incomplete historical sales records, will produce unreliable output. The data quality assessment in Check 4 and the AI readiness assessment in this check are connected work streams.

Organizations that assess AI readiness as an afterthought - or not at all - will reach go-live with a clean S/4HANA system and still need a subsequent project to unlock the AI capabilities they paid for.

How ITChamps Approaches Your Readiness Assessment

A readiness assessment is only as useful as the decisions it enables. An output of hundreds of custom code objects, dozens of open interfaces, and a database sizing spreadsheet is not a roadmap. It is a list of problems with no resolution priority.

ITChamps' 3PS Advisory framework structures the readiness assessment to produce decision-ready outputs across three dimensions - Platform, Process, and People - that map directly to project planning inputs.

• On the Platform dimension, ITChamps delivers a custom code disposition report at the object level, an integration inventory with re-platforming recommendations, a data volume and quality summary with archiving recommendations, and a hosting model analysis with five-year TCO comparison. These outputs are not advisory summaries. They are the inputs your project management office needs to build a defensible budget and timeline.

• On the Process dimension, ITChamps maps current business processes against S/4HANA standard functionality and Fiori application groups, identifying consolidation opportunities and change management scope before the blueprint phase begins. Organizations that skip this step consistently discover process-driven project scope expansion after go-live commitments have been made.

• On the People dimension, ITChamps assesses internal team capability against the skills required for each project phase - from ABAP remediation to Basis migration execution to end-user training design - and identifies where partner augmentation or specialist capability is required.

• As an SAP Gold Partner, ITChamps aligns assessment outcomes with SAP S/4HANA Cloud architecture and SAP Business AI capabilities, ensuring that the roadmap delivered reflects current SAP platform capabilities - not a generalized migration template.

The outcome of an ITChamps readiness assessment is a risk-mitigated migration roadmap that your CIO can present to the board with confidence - and that your migration team can execute against without discovering the scope they were not told about.

Don't estimate your migration complexity. Book an ITChamps S/4HANA Readiness Assessment to build a roadmap grounded in your actual landscape.

Frequently Asked Questions

What is an SAP S/4HANA readiness assessment and what does it cover?

An SAP S/4HANA readiness assessment is a structured discovery engagement that evaluates your current SAP ECC landscape across six dimensions before a migration project begins: custom code and Clean Core alignment, business process fit with S/4HANA standard functionality, integration architecture and SAP BTP readiness, data volume and quality, cloud hosting model selection, and SAP Business AI readiness. The output is a prioritized, decision-ready migration roadmap - not an automated compatibility report. A thorough assessment prevents the technical debt, budget overruns, and integration surprises that derail migrations after project commitments have been made."

How long does an S/4HANA readiness assessment take?

Assessment duration varies based on landscape complexity, the size of the custom code estate, the number of active integrations, and the geographic scope of the SAP deployment. A focused assessment of a mid-size ERP landscape typically runs between four and eight weeks. Larger, multi-country landscapes with extensive customization may require ten to fourteen weeks for a thorough assessment that produces actionable project inputs. Timelines should always be confirmed with your migration advisory partner after an initial landscape review."

What is Clean Core and why does it matter for the readiness assessment?

Clean Core is SAP's architectural standard for S/4HANA deployments. It requires that any extension of S/4HANA functionality be built using SAP's published APIs and extension points - not through direct modification of core SAP code, tables, or business objects. Maintaining a Clean Core posture ensures that each SAP release upgrade applies cleanly without requiring custom code regression testing, that SAP Business AI features can activate without interference from non-standard customizations, and that SAP support obligations remain intact. The readiness assessment determines the current custom code estate's conformance with Clean Core standards and produces a remediation or re-platforming plan for non-conforming objects."

Should we choose RISE with SAP or a private cloud deployment for S/4HANA?

This decision depends on your organization's technical requirements, data residency obligations, existing hyperscaler enterprise agreements, internal Basis capability, and long-term cloud strategy. RISE with SAP packages S/4HANA Cloud Private Edition with managed infrastructure, BTP entitlements, and SAP Business Network access in a subscription model that reduces Basis operational overhead. It is a strong fit for organizations prioritizing managed services and predictable OpEx. However, organizations with significant hyperscaler commitments, specific sovereignty requirements, or complex customization needs may find that a non-RISE private cloud deployment better aligns with their overall IT architecture. The readiness assessment should include a structured hosting model evaluation with five-year total cost of ownership modeling before this decision is finalized."

What happens if we skip the readiness assessment and go directly to project execution?",

Organizations that begin S/4HANA migration execution without a structured readiness assessment consistently encounter the same failure modes: custom code volumes that exceed the remediation budget allocated at project start, integration dependencies that are discovered during the blueprint phase and require unplanned re-platforming work, data quality issues that create a critical-path cleansing workload during the migration execution phase, and hosting or licensing decisions that are reversed mid-project at significant cost. Gartner projects that 70% of large enterprise ERP migrations will experience severe budget overruns by 2027 due to unmitigated technical debt discovered too late. The readiness assessment is the mechanism for uncovering that debt before it becomes a project crisis."

SAP, SAP S/4HANA, RISE with SAP, SAP BTP, SAP Business Technology Platform, SAP ECC, SAP Fiori, SAP Business AI, Joule, and other SAP products and services mentioned herein, as well as their respective logos, are trademarks or registered trademarks of SAP SE in Germany and other countries. ITChamps is an independent entity and is not affiliated with SAP SE. All views expressed herein are those of ITChamps.

Migration timelines and project durations referenced in this article are illustrative estimates based on typical landscape characteristics. Actual timelines vary based on landscape size, customization complexity, integration scope, data volume, and organizational readiness. No guaranteed migration timeline is implied or should be inferred.

Cost reduction figures and maintenance savings referenced in this article are based on third-party research and industry data. Actual results depend on individual organization circumstances. No guaranteed return on investment, total cost of ownership reduction, or cost savings outcome is implied or should be inferred from figures cited in this article.