How do you build a business case for SAP S/4HANA migration in 2026?

To build a business case for SAP S/4HANA migration in 2026, you need to clearly define the total cost of the transition, quantify the operational and financial benefits, align the case with your organisation’s strategic goals, and present a realistic timeline with measurable outcomes. A strong business case does not just justify the investment — it gives your board a credible roadmap for how the organisation will get from where it is now to where it needs to be. The sections below answer the most common questions finance and IT leaders face when putting this case together.

What are the core components of an SAP S/4HANA migration business case?

A solid SAP S/4HANA migration business case has four core components: a current state assessment, a cost model, a benefits analysis, and a delivery approach. Together, these give decision-makers a complete picture of the investment, the expected return, and the risks involved. Without all four, the case is incomplete and unlikely to survive board scrutiny.

The current state assessment documents where the organisation stands today — which legacy systems are in use, where processes break down, and what the cost of inaction looks like. This is where a maturity assessment adds real value. At Optinus, we typically start here, giving organisations a clear baseline before any budget or roadmap is committed. That baseline makes the rest of the business case far more credible because it is grounded in actual data rather than assumptions.

The cost model covers everything from licences and implementation to training and post-go-live support. The benefits analysis translates operational improvements into financial terms. And the delivery approach explains how the migration will be managed, who is responsible for what, and how risks will be controlled. Each component needs to hold up on its own and connect logically to the others.

What costs should you include in an SAP S/4HANA migration budget?

An SAP S/4HANA migration budget should include software licences, implementation services, infrastructure, data migration, testing, training, change management, and post-go-live support. Many organisations underestimate the non-technical costs — particularly change management and hypercare — which are often where migrations run over budget.

Here is a practical breakdown of the cost categories to include:

Software and licences: SAP S/4HANA licensing fees, cloud hosting or on-premises infrastructure costs
Implementation services: External consultants, system integrators, and internal resource time
Data migration: Cleansing, mapping, testing, and validating data from legacy systems
Testing: Unit testing, integration testing, user acceptance testing, and automated test tooling
Training and change management: End-user training, communication programmes, adoption support
Cutover and go-live: Cutover planning, parallel run costs, hypercare and aftercare
Contingency: Typically 15 to 20 percent of the total budget for scope changes and delays

One cost that often gets underestimated is data migration management. Poor data quality going into a new system creates problems that are expensive to fix after go-live. Budget for rigorous As-Is/To-Be analysis and testing upfront — it is far cheaper than remediation later.

How do you quantify the ROI of an SAP S/4HANA migration?

To quantify the ROI of an SAP S/4HANA migration, you calculate the total expected benefits over a defined period — typically three to five years — and compare them against the total cost of the migration. Benefits should be expressed in financial terms wherever possible, covering both hard savings and productivity gains.

Common benefit categories to quantify include:

Process efficiency: Reduction in manual processing time, fewer workarounds, faster reporting cycles
Inventory and supply chain optimisation: Lower stock levels, better demand visibility, reduced carrying costs
Finance and compliance: Faster period-end close, improved audit trails, reduced compliance risk
IT cost reduction: Decommissioning legacy systems, lower maintenance costs, simplified IT landscape
Workforce productivity: Time saved through automation, better self-service tools, reduced duplication

The honest challenge here is that some benefits are difficult to attribute directly to the SAP migration. Use conservative estimates and be transparent about your assumptions. A business case that acknowledges uncertainty is more credible than one that promises unrealistic returns. Where possible, benchmark against comparable organisations that have completed similar migrations.

What’s the difference between a greenfield and brownfield SAP migration for business case purposes?

For business case purposes, the key difference between a greenfield and brownfield SAP migration is scope and risk. A greenfield implementation builds the new system from scratch, which offers more flexibility but typically costs more and takes longer. A brownfield migration converts the existing SAP system to S/4HANA, preserving more of the current configuration and data, which reduces cost but carries more technical complexity around legacy customisations.

Greenfield business case considerations

A greenfield approach allows you to redesign business processes from the ground up, which can deliver larger long-term benefits. However, the business case needs to account for higher implementation costs, longer timelines, and more significant change management requirements. The benefits are often larger, but so is the investment — and the risk.

Brownfield business case considerations

A brownfield migration typically has a lower upfront cost and shorter timeline, making it easier to justify to the board. The risk profile shifts, though: legacy customisations need to be assessed, and technical debt can surface during the conversion. The business case should include a thorough assessment of existing customisations and a clear position on which ones to retain, simplify, or eliminate.

Both approaches benefit from program management that aligns delivery with business goals across multiple workstreams. The choice between greenfield and brownfield should be driven by the organisation’s strategic ambitions, not just cost — and that argument needs to be explicit in the business case.

Why do SAP S/4HANA business cases fail to get board approval?

SAP S/4HANA business cases most often fail to get board approval because they focus too heavily on technical detail and not enough on business outcomes, or because the cost model is incomplete and the benefits are vague. Boards approve investments that are clearly linked to strategic priorities and backed by realistic, well-evidenced numbers.

The most common reasons for rejection include:

Benefits are not quantified: Describing improvements in general terms without attaching financial value gives the board nothing to approve
Costs are underestimated: Missing change management, hypercare, or contingency budgets makes the case look underprepared
Risk is not addressed: A business case that does not acknowledge delivery risk or explain how it will be managed raises more concerns than it resolves
No clear ownership: Boards want to know who is accountable for delivery, not just who wrote the document
Strategic alignment is weak: If the migration is not clearly connected to a business priority the board already cares about, it becomes easy to defer

One practical way to strengthen the case is to present a phased approach with decision points, rather than asking for approval of the full investment upfront. This reduces perceived risk and gives the board confidence that the organisation can course-correct if needed. Explore our full range of services to understand how each phase of a transformation can be structured and supported.

How Optinus helps you build a stronger SAP S/4HANA business case

Building a credible business case for SAP S/4HANA migration requires more than a spreadsheet. It requires an honest view of where you are today, a realistic model of what the migration will cost and deliver, and a delivery approach that the board can trust. That is exactly where we come in.

Here is how we support organisations at this stage:

Maturity assessment: We give you a clear baseline of your current ERP and process maturity before any budget is committed, so your business case is built on facts, not assumptions
Cost and scope clarity: Our consultants have hands-on experience from real SAP migrations at leading multinationals, which means we know where budgets typically go wrong and how to avoid it
Greenfield and brownfield expertise: We work across both approaches and help you make the right choice for your organisation’s goals and constraints
End-to-end delivery confidence: From data migration and test management to cutover and change management, we cover the full transformation journey under one roof
Available on-site and remote: We work with organisations across the Netherlands, Belgium and internationally, adapting to your team’s setup

If you are preparing a business case for SAP S/4HANA migration and want a partner with real-world experience behind it, get in touch with our team or learn more about what we do.

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