S/4HANA Migration Assessment Tool: Greenfield vs Brownfield

Using the tool is simple, but what it reveals can save you from costly missteps later. The idea is to help you make a decision—Greenfield, Brownfield, or something in between—based on where your system stands today and where you want to go. Here’s how to walk through it:

1. System Age (Years since go-live)

Start by selecting how long your current SAP system has been running. A newer system (1–4 years) might lean toward Brownfield, especially if things are still working smoothly. A mid-age system (5–9 years), like in this example, may have accumulated inefficiencies but still hold some value worth preserving. Older systems (10+ years) often push companies to consider a cleaner break.

2. Number of Custom Objects (Z objects)*

Custom code is a big deal in migration planning. If you’re sitting on 151–400 custom objects, that’s a moderate level of complexity. Enough to matter. The more Z-code you have, the harder it is to convert cleanly—especially if you don’t know what’s actively used. Brownfield might keep these intact, but Greenfield lets you clean house.

3. Data Quality

Next, assess your data. Be honest. Is it clean? Consistent? If your answer is “some validation, some inconsistencies,” that lands you in the middle. You probably have data that’s usable but needs some prep before moving. Greenfield may force you to clean it anyway. Brownfield might move it as-is—which can be risky. The tool factors this in.

4. Need for Business Process Redesign

If you’re only redesigning “some key areas,” that suggests you’re not overhauling everything. In that case, Selective Transition becomes a real contender. It lets you fix what’s broken without tossing the entire system. Full redesign? You’re leaning Greenfield. Minimal change? Brownfield might be enough.

5. Historical Data Retention

Do you really need every transaction from the past decade? Or just the important business records? “Selective” retention means you can afford to leave some of the past behind. That’s a good fit for Greenfield or Selective Transition, where you’re not pulling all historical data into the new system. Brownfield brings everything unless you filter it.

6. Project Budget (USD)

Last—but not minor—is your budget. A moderate budget ($1M–$5M) often rules out a full custom Selective Transition unless it’s scoped very tightly. Greenfield and Brownfield both can fit this range, but scope control is key. Brownfield is often cheaper up front; Greenfield may cost more now but save you in long-term maintenance. The tool weighs that trade-off.

Once you fill in each of these parameters, just hit “Calculate Recommendation”. You’ll get a strategy suggestion, plus an explanation that maps directly to your inputs. It’s not a magic formula, but it gives you a grounded starting point—one that’s easier to trust than a gut feeling or vendor pitch.