Greenfield vs. brownfield - decision criteria for DACH SMEs

Q: Can I do greenfield with RISE Public Cloud?

Yes, it's even the recommended combination. SAP positions RISE Public Cloud as ideal for greenfield: you start with a clean S/4HANA architecture in the cloud, without on-prem debt. Public Cloud spins up faster than private cloud and has lower operating costs. If you think greenfield, public cloud is the complementary deployment. Brownfield pairs better with RISE Private Cloud because you can run complex legacy landscapes longer.

Q: How long does greenfield vs. brownfield really take?

Greenfield: 12–18 months (typical for Mittelstand, 500–5,000 employees). Big-bang go-live at the end. Brownfield: 10–14 months, but value comes later. Selective Data Transition: 14–16 months with phased go-live per module. From our practice: absolute end dates differ little. Difference lies in how many users work productively after month 6.

Q: What costs are realistic?

Greenfield: 1.5 to 4 million euros (for 500–5,000 employees). Brownfield: 1.2 to 3 million euros (similar to greenfield, but software costs can be higher). Selective Data Transition: 1.4 to 3.5 million euros with better risk reduction per euro spent. Honest scoping: total-cost difference is often under 15%. Risk difference is larger.

Q: What exactly is Selective Data Transition?

SDT (also bluefield) is a hybrid: you build a new SAP S/4HANA system (greenfield), but copy only selected data from legacy. Typically: historical orders and customers → migrate, pure duplicates and errors → delete, don't migrate, transaction data → re-enter or selectively migrate. This is officially integrated in RISE 2024/2025. Cost: 10–20% higher than pure greenfield, but 30–40% lower risk.

The two approaches at a glance

Greenfield means a completely new implementation. Brownfield means migration of existing data and processes into a new system.

Greenfield (greenfield): The system is set up from scratch. You opt for a modern ERP system - such as SAP S/4HANA with SAP RISE in the public cloud - and redefine processes and data structures, unencumbered by technical debt from older systems. The implementation typically takes 12-18 months, but requires intensive business process redesign and a high level of internal willingness to change.

Brownfield : You migrate the existing ERP system (usually SAP ECC) to a more modern system (S/4HANA) or adapt an existing system. The existing data, processes and often customizations are transferred to the new system. This approach is typically faster and less expensive in terms of direct implementation costs, but often multiplies the technical debt.

A third option, Selective Data Transition (SDT, also known as Bluefield), is gaining importance in the midmarket: you copy the system shell into the new SAP (greenfield-like), but only migrate selected data from the legacy system instead of everything. This reduces disruption, but does not preserve all complexity.

When greenfield is the right choice

Greenfield works when your legacy data is so bad that re-entry is more economical than migration.

Legacy data junk exceeds tolerance. A mechanical engineering company with 1,800 employees had been running SAP R/3 for over 20 years, but 40% of its master data was duplicated, miscategorized or inconsistent. Data cleansing cost more time than entering new data. Greenfield made it possible to start again with clean master data.
You want to fundamentally rethink processes. If you not only want to modernize, but also fundamentally redesign order-to-cash, procure-to-pay or other core processes, Greenfield is the clean way to go. Brownfield automatically lures you into the old process logic.
Your legacy customizations are architecturally fragile. Over the years, many SMEs have built special ABAP developments into the system that are not well documented and are based on SAP R/3 logic. Migrating these to S/4HANA often costs more than a new implementation with standard solutions.
They have low staffing levels and low IT debt. A small company just starting out with ERP or just migrating from Excel has little to lose. Greenfield is low risk here.
RISE Public Cloud fits your business model. SAP promotes RISE with Public Cloud as ideal for Greenfield (simpler architecture, fast rollout). If you are not tied to legacy customizations or very specific on-prem requirements, Public Cloud + Greenfield is a clear combination.

When brownfield is the right choice

Brownfield works when your data is still usable and your critical processes are documented.

Your ERP data is of high quality. If you have invested years in data maintenance and your master data, transaction data and customer entries are consistent, a migration is worthwhile. A food manufacturer with clean product master data and tracked batch processes - Brownfield made sense here as the data quality was already in place.
They have little time for process redesign. A retailer with 150 locations could not afford weeks of business interruption. Brownfield allowed them to migrate from ECC to S/4HANA in 6 months without taking cash registers or stock offline.
Your customizations are documented and SAP-standard. If your ABAP developments only extend standard logic (e.g. additional reporting, simple field validations), they are often relatively easy to migrate.
RISE Private Cloud or On-Prem is architecturally necessary. Brownfield fits well with Private Cloud (you can keep more complex landscapes running). If you need private cloud, brownfield is often the more practical choice than greenfield.
Your business continuity is critical. Financial services, insurers and highly regulated industries have little tolerance for long go-live interruptions. Brownfield reduces these risks - if the data quality is right.

Practical example: A real Dreher selection decision

A kitchen manufacturer with ~2,000 employees and international business had to choose between Greenfield and Brownfield - and the decision determined everything that followed.

The company had been running on SAP R/3 since the mid-1990s. During the audit, we discovered that the customer master data had accumulated over a decade and contained thousands of duplicates. The product hierarchy had grown historically and was not consistent. However, order processing was documented, production planning was stable and the interfaces to the international logistics partners were established.

A pure greenfield approach would have meant: complete data re-entry (6+ months), complete process redesign (4-6 months), risk to supply chain continuity in the first few weeks after go-live.

We opted for a Selective Data Transition (SDT) hybrid: New S/4HANA shell (greenfield structure), but only migrated the proven orders and customer relationships, leaving duplicates in the legacy system. New customers were entered directly into the new system. The implementation took 14 months instead of 12, but supply chain continuity was guaranteed from day 1 and we did not have a multi-million euro risk for a data re-entry.

What happened afterwards: Employees accepted the system faster because familiar customer relationships and orders were still there. The rate of data entry errors was half that of a pure greenfield project that we carried out in parallel with another customer.

What the greenfield vs. brownfield debates usually overlook

The three biggest gaps in the public debate are: (1) Selective Data Transition (SDT/Bluefield) as a third, practical path for SMEs, (2) change management as the bigger risk than technical debt, and (3) DSAG market data showing that pure greenfields are rarer in German SMEs than assumed.

1 Selective Data Transition (SDT) / Bluefield as the SME sweet spot

Most debates present greenfield and brownfield as a binary choice. In practice, we use a third way: Selective Data Transition. This involves setting up a new SAP environment (greenfield), but only migrating selected historical data - not everything. This is particularly relevant for SMEs because it reduces the data cleansing load by 40-60% compared to brownfield, preserves operational continuity (no 24-hour blackout go-live) and allows phased go-lives per module (Orders → Finance → Procurement). SAP has included SDT 2024-2025 as an official program in the RISE implementation. SNP Group and Syniti are positioning this as a "Goldilocks option" - not too disruptive like Greenfield, not burdened by legacy debt like Brownfield. Yet it is missing from German ERP textbooks and vendor pitches, where greenfield/brownfield rhetoric dominates.

2. change management is the bigger risk than data migration

Here we speak a clear truth from 1,200+ projects: Technically, both approaches work. Projects don't fail because of data - they fail because of people. A greenfield project with poor change management leads to employees who do not understand the new system. A brownfield project with good change communication leads to rapid acceptance. The DSAG Investment Report 2024 documents this indirectly: 73% of SMEs that chose brownfield report "good user acceptance" after 6 months. Of those who chose Greenfield, 58% report acceptance problems in the first 3 months - not because of the new data, but because processes have changed "too radically". A kitchen manufacturer with restrictive change management would have struggled with Greenfield even if the data had been perfect.

3 DSAG market data contradicts the "greenfield is more modern" narrative

The DSAG data shows for the German-speaking SAP midmarket: 20 % greenfield, 39 % brownfield, 41 % hybrid / bluefields (SDT, Selective Migration). This is completely different from what vendor marketing suggests. It shows: SMEs are more conservative in their choices, but are increasingly choosing hybrid approaches, not pure greenfield. Anyone who portrays greenfield as "more modern" is ignoring this market data.

Our classification: Greenfield is faster in theory, more expensive in practice. Brownfield is slower, but its change management challenges are often underestimated. Selective data transition is the way forward for 60% of SMEs - and the debate should be framed in terms of this, not a greenfield vs brownfield dichotomy.

Decision criteria checklist

Answer these 13 questions honestly. Most yes answers at 1-5 indicate Greenfield. Most yeses at 6-13 indicate brownfield or SDT.

Data quality (1-5)

Is more than 30% of your master data (customers, products, suppliers) duplicate or inconsistent? Yes → Greenfield is becoming more interesting. No → Brownfield or SDT is becoming more practical.
Have you systematically measured and documented data quality in the last 3 years? Yes → You know what you have. Brownfield risks less. No → You could experience surprises during migration.
Would a data re-acquisition (instead of migration) cost less than 4 months? Yes → Greenfield is economically advantageous. No → Brownfield or SDT are more cost-effective.

Process documentation (6-8)

Are your top 5 business processes (order-to-cash, procure-to-pay, etc.) documented with defined owners? Yes → You can migrate them (brownfield). No → You must redefine them (greenfield).
Have you carried out process audits or process mining in the last 2 years? Yes → You know how you currently work; brownfield becomes easier. No → You might have surprises when redefining.
Would you copy your current business processes into the new system with 80%+ similarity? Yes → Brownfield makes sense. No → Greenfield forces you to redefine (often better).

Business continuity (9-10)

Can you tolerate a productive business interruption of more than 48 hours? Yes → Greenfield or Brownfield with Big Bang are possible. No → You need phased go-live (SDT).
Do you have interfaces to critical system landscapes (banking, insurance, logistics) that are difficult to separate from the system? Yes → Brownfield or SDT reduce interface risks. No → Greenfield is less complicated.

Customizings & Legacy (11-13)

Do you have more than 50 special ABAP programs or workflow customizations that are actively used? Yes → Brownfield would be cheaper to migrate (if still documented). No → Greenfield with standard is less complex.
Are these customizations well documented and maintained by a developer? Yes → Brownfield can migrate them. No → Greenfield forces you to go back to Standard (often better, even if painful).
Are you running specific on-prem or private cloud requirements that public cloud can't fulfill? Yes → You need to use RISE private cloud or on-prem; brownfield is a better fit. No → RISE Public Cloud + Greenfield is a clear combination.
Do you have external partners (logistics providers, creditors) that are firmly integrated into your current interfaces? Yes → Brownfield or SDT minimize changeovers. No → Greenfield with newly defined interfaces is less risky.
Is your IT department small (< 5 people for ERP operations) or managed externally? Yes → Brownfield is less maintenance-intensive; greenfield requires more owners. No → Greenfield requires less supervision if well rolled out.

Next steps

This decision deserves deeper consideration - you shouldn't sit on it alone. In our 30-minute consultation, we will guide you through a structured data quality check and an honest process assessment. Afterwards, you will have clarity on which path suits your company.

Häufig gestellte Fragen

Can I do greenfield with RISE Public Cloud?

Yes, it's even the recommended combination. SAP positions RISE Public Cloud as ideal for greenfield: you start with a clean S/4HANA architecture in the cloud, without on-prem debt. Public Cloud spins up faster than private cloud and has lower operating costs. If you think greenfield, public cloud is the complementary deployment. Brownfield pairs better with RISE Private Cloud because you can run complex legacy landscapes longer.

How long does greenfield vs. brownfield really take?

Greenfield: 12–18 months (typical for Mittelstand, 500–5,000 employees). Big-bang go-live at the end. Brownfield: 10–14 months, but value comes later. Selective Data Transition: 14–16 months with phased go-live per module. From our practice: absolute end dates differ little. Difference lies in how many users work productively after month 6.

What costs are realistic?

Greenfield: 1.5 to 4 million euros (for 500–5,000 employees). Brownfield: 1.2 to 3 million euros (similar to greenfield, but software costs can be higher). Selective Data Transition: 1.4 to 3.5 million euros with better risk reduction per euro spent. Honest scoping: total-cost difference is often under 15%. Risk difference is larger.

What exactly is Selective Data Transition?

SDT (also bluefield) is a hybrid: you build a new SAP S/4HANA system (greenfield), but copy only selected data from legacy. Typically: historical orders and customers → migrate, pure duplicates and errors → delete, don't migrate, transaction data → re-enter or selectively migrate. This is officially integrated in RISE 2024/2025. Cost: 10–20% higher than pure greenfield, but 30–40% lower risk.

Häufig gestellte Fragen

Can I do greenfield with RISE Public Cloud?

How long does greenfield vs. brownfield really take?

What costs are realistic?

What exactly is Selective Data Transition?

Dr. Harald Dreher
Owner & Senior Consultant · Dreher Consulting ^®

Dr. Harald Dreher has been advising managing directors in medium-sized companies in Germany, Austria and Switzerland (DACH region) on digitization, ERP and AI strategy decisions for over 30 years. Over 1,200 completed projects. Owner-managed, vendor-neutral, with own AI model SCOReX®.

About Dr. Harald Dreher · Editorial standards

Greenfield vs. Brownfield — Decision-Making Criteria for SMEs in the DACH Region

The two approaches at a glance

When greenfield is the right choice

When brownfield is the right choice

Practical example: A real Dreher selection decision

What the greenfield vs. brownfield debates usually overlook

Decision criteria checklist

Häufig gestellte Fragen

Häufig gestellte Fragen

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