S/4HANA Path Chooser
Not sure whether to go Greenfield, Brownfield, or Selective? This interactive guide walks through real-world decision factors to help you find the right fit.
The Three Paths at a Glance
Greenfield
Clean-slate implementation. New system, fresh start, transform processes.
- • New system ID
- • Process redesign
- • Selective data migration
- • 18-36 months typical
Brownfield
Technical conversion. Same system ID, minimize change, convert in place.
- • Same system ID
- • Keep processes as-is
- • Full data conversion
- • 12-24 months typical
Selective
Hybrid approach. New system, selective data, mix of old and new processes.
- • New system ID
- • Selective redesign
- • Filtered data migration
- • 15-30 months typical
Decision Framework: Key Questions
1. How clean is your data?
Clean & Well-Governed
Master data is accurate, minimal duplicates, strong MDM, regular archiving
→ Brownfield or Selective
Mixed Quality
Some data issues, manageable cleanup, selective archiving needed
→ Selective
Poor Quality
Major quality issues, duplicates, inactive records, no MDM, massive volumes
→ Greenfield
2. What's your custom code situation?
Minimal & S/4-Compatible
Under 500 objects, mostly compatible, limited business criticality
→ Brownfield
Moderate with Issues
500-2,000 objects, some compatibility issues, can remediate selectively
→ Brownfield or Selective
Extensive Technical Debt
Over 2,000 objects, major compatibility issues, obsolete functionality
→ Greenfield or Selective
3. How well do your processes fit SAP standard?
Close to Standard
Mostly vanilla SAP, few unique requirements, standard industry processes
→ Brownfield
Some Customization Needed
Mix of standard and custom, some unique requirements, manageable
→ Brownfield or Selective
Highly Unique
Heavily customized, unique industry, complex requirements, transformation desired
→ Greenfield
4. What's your organization's appetite for change?
Minimize Disruption
Low tolerance for change, keep what works, avoid retraining
→ Brownfield
Targeted Improvement
Open to change in problem areas, keep what works, selective transformation
→ Selective
Full Transformation
Ready to rethink processes, embrace change, business transformation driver
→ Greenfield
5. What are your timeline and budget constraints?
Time-Constrained
Need to move in 12-18 months, limited budget, minimize risk
→ Brownfield
Moderate Constraints
18-24 months acceptable, reasonable budget, balanced approach
→ Selective
Strategic Investment
24-36 months acceptable, significant budget, long-term value focus
→ Greenfield
6. How much historical data do you need online?
All Historical Data
Need full transaction history, reporting requirements, regulatory retention
→ Brownfield
Selective History
Need recent data (3-5 years), archive rest, manageable volumes
→ Selective
Fresh Start
Minimal history needed (1-2 years), archive old system, clean slate
→ Greenfield
Detailed Path Comparison
| Factor | Greenfield | Brownfield | Selective |
|---|---|---|---|
| Timeline | 18-36 months | 12-24 months | 15-30 months |
| Cost | Highest (full implementation) | Lowest (technical upgrade) | Medium (hybrid approach) |
| Business Risk | High (big bang change) | Low (minimal disruption) | Medium (targeted change) |
| Technical Risk | Low (fresh system) | High (carry forward debt) | Medium (selective cleanup) |
| Process Change | Complete redesign | Minimal change | Selective redesign |
| Testing Effort | Full E2E testing | Regression + delta | Full for new, regression for old |
| Training | Complete retraining | Fiori UI + delta training | Selective retraining |
| Cutover Downtime | Days to weeks (data migration) | Hours to days (in-place conversion) | Days (selective migration) |
Hybrid Approaches
Phased Greenfield
Start with core modules greenfield (FI/CO, MM, SD), then add remaining modules in waves. Keeps initial scope manageable while getting transformation benefits.
- • Phase 1: Core financials and supply chain (12-18 months)
- • Phase 2: Manufacturing or logistics (6-12 months)
- • Phase 3: Specialized modules (6-12 months)
Brownfield with Selective Redesign
Convert most modules brownfield, but greenfield specific problem areas (e.g., new warehouse management, clean FI-AA, redesigned costing).
- • Brownfield base conversion (12-18 months)
- • Greenfield redesign for 1-2 modules (parallel or follow-on)
- • Best of both: speed + targeted transformation
Shell Conversion + Selective Migration
Convert empty ECC shell to S/4, then migrate data selectively by entity, company code, or module. Allows parallel running and gradual cutover.
- • Convert empty system (3-6 months)
- • Migrate entities in waves (6-12 months each)
- • Minimize big bang risk, extend timeline