SAP S/4HANA Migration: Cost, Timeline & a Step-by-Step Plan
With mainstream support for SAP ECC ending in 2027, S/4HANA is no longer optional. Here's how the migration paths compare, what really drives cost and timeline, and a step-by-step plan to get there safely.
- SAP S/4HANA migration is now a deadline-driven project: mainstream maintenance for SAP ECC ends in 2027, so most enterprises need a credible plan in motion well before then.
- There are three routes — a brownfield system conversion, a greenfield reimplementation, or a selective (bluefield) transition — and the right one depends on how much of your current setup is worth keeping.
- Cost and timeline are driven by system size, custom code, data quality and integrations — not a fixed price, which is why every serious move starts with a readiness assessment.
Moving to SAP S/4HANA is one of the largest software decisions an enterprise makes — and with mainstream support for SAP ECC ending in 2027, it's no longer a question of if, but when and how. This guide explains the migration paths, what actually drives the cost and timeline, the pitfalls to avoid, and a practical, step-by-step plan to get there with minimal disruption.
Why move to S/4HANA now
The 2027 deadline is the headline reason, but it isn't the only one. Putting the move off shortens your runway and pushes you into a crowded market for SAP talent later. The upsides are real too:
- Mainstream maintenance for most SAP ECC releases ends in 2027, with extended support after that at a premium.
- S/4HANA runs on the in-memory HANA database, enabling real-time reporting and a simpler data model.
- The Fiori user experience replaces dated SAP GUI screens with modern, role-based apps.
- It's the foundation for SAP's cloud roadmap, AI features and clean-core extensibility.
- Starting early means a calmer timeline, better talent availability, and time to clean up data and custom code.
Treat 2027 as a planning horizon, not a finish line. Readiness assessments, data cleanup and custom-code remediation are the long poles — start them early.
Brownfield, greenfield or selective: the three migration paths
How you get to S/4HANA matters as much as getting there. The three approaches trade off speed, cost and how much of a fresh start you get:
| Path | Best for | What happens |
|---|---|---|
| Brownfield (system conversion) | Stable processes worth keeping | Convert the existing system in place, retaining config, data and history |
| Greenfield (new implementation) | Outdated processes, fresh start | Build a clean S/4HANA system and re-engineer processes from best practice |
| Selective / bluefield | Large landscapes, mixed needs | Migrate selected data, processes and code into a new system on your terms |
There's no universally right path. Brownfield is usually faster and cheaper; greenfield buys you a clean core and modern processes; selective splits the difference for complex landscapes.
What drives the cost and timeline
Anyone who quotes a fixed S/4HANA price before seeing your system is guessing. The number is driven by a handful of factors that vary enormously between businesses:
- System size and data volume — more data means longer migration and cleanup.
- Custom code (Z-code) — every custom program needs to be assessed, adapted or retired for S/4HANA compatibility.
- Number and complexity of integrations — interfaces to banks, CRMs, warehouses and third parties all add work.
- Data quality — duplicate, stale or inconsistent master data slows everything down and is best fixed before you move.
- Deployment target — public cloud, private cloud (RISE with SAP) or on-premise each carry different effort and cost shapes.
- Process change — the more you re-engineer versus convert, the more testing and change management you take on.
A step-by-step S/4HANA migration plan
A successful migration is a sequence of de-risking steps, not a big-bang switch. This is the path we follow:
- Readiness assessment — run SAP Readiness Check, inventory custom code and integrations, and pick the right path.
- Business case & scope — agree the deployment model, processes in scope, and a phased timeline.
- Data cleanup & archiving — fix master data and archive what you don't need to carry over.
- Custom-code remediation — adapt or retire Z-code, moving toward a clean core with side-by-side extensions.
- Build & convert in a sandbox — stand up the S/4HANA system and run a trial conversion.
- Test thoroughly — functional, integration, performance and user-acceptance testing across cycles.
- Cutover & go-live — a planned, rehearsed cutover with a clear rollback option.
- Hypercare & optimise — intensive post-go-live support, then ongoing improvement and Fiori rollout.
Common pitfalls to avoid
- Carrying over years of unused custom code instead of cleaning the core.
- Underestimating data cleanup — it's almost always bigger than expected.
- Leaving testing and change management to the end.
- Treating it as a pure IT project rather than a business transformation.
- Starting too late and paying a premium for scarce talent near the deadline.
Not sure which path fits your SAP landscape?
We'll run a readiness assessment of your current system — custom code, data and integrations — and come back with a recommended path and a realistic, phased plan. No fixed quote before we understand your system.
How Acqurio Tech can help
We help mid-market and enterprise teams plan and deliver S/4HANA migrations without the disruption:
- SAP development & migration — readiness assessment, path selection and end-to-end delivery.
- Hire SAP consultants — pre-vetted SAP talent to extend your team for the project.
- Enterprise software development — clean-core extensions and integrations around SAP.
- Cloud & DevOps — the infrastructure and pipelines for a cloud S/4HANA landscape.
Conclusion
S/4HANA migration is a deadline-driven transformation, not a routine upgrade. The teams that come out ahead start early, choose the path that matches how much of their setup is worth keeping, and treat data cleanup and custom-code remediation as the real work. Begin with a readiness assessment, phase the rollout, and the 2027 deadline becomes a plan rather than a panic.
Frequently asked questions
When does support for SAP ECC end?
Mainstream maintenance for most SAP ECC (Business Suite 7) releases ends in 2027, with extended support available afterwards at additional cost. That makes a credible S/4HANA plan a priority for most SAP customers well before then.
What's the difference between brownfield and greenfield S/4HANA migration?
Brownfield (system conversion) migrates your existing system in place, keeping configuration, data and history — it's usually faster and cheaper. Greenfield builds a brand-new system and re-engineers processes from best practice, which is more effort but gives you a clean core. A selective or bluefield approach blends the two.
How long does an S/4HANA migration take?
It depends on system size, custom code, data quality and how much process change you take on. A focused brownfield conversion is much quicker than a full greenfield reimplementation. A readiness assessment is the fastest way to get a realistic timeline for your landscape.
How much does S/4HANA migration cost?
There's no fixed price — cost is driven by data volume, custom code, integrations, deployment model and the degree of process change. We don't quote a number before assessing your system; a readiness assessment produces a tailored estimate.
Do we have to move to the cloud?
No. S/4HANA can run on public cloud, private cloud (including RISE with SAP) or on-premise. The right target depends on your IT strategy, compliance needs and appetite for managing infrastructure.
What happens to our custom ABAP code?
Every custom program is assessed for S/4HANA compatibility, then adapted, replaced with standard functionality, or retired. Moving custom logic to side-by-side extensions keeps the core clean and makes future upgrades far easier.
Can we keep running during the migration?
Yes. A well-planned migration uses sandbox builds, multiple test cycles and a rehearsed cutover with a rollback option, so your live operations keep running until a planned go-live.