Everything you need to plan an SAP ECC to S/4HANA migration in 2026 — brownfield conversion, greenfield re-implementation, and hybrid selective-data-transition paths compared on cost, risk, timeline, and business outcomes.
Eighteen sections, grouped by the decision each one helps you make. Jump straight to the part you need.
SAP has confirmed end-of-mainstream-maintenance for SAP ERP 6.0 on 31 December 2027 — but that date applies to enhancement packages 6, 7 and 8 only. If you are running SAP ERP 6.0 with no enhancement package, or EhP 1 to 5, mainstream maintenance already ended on 31 December 2025, and extended maintenance is not offered for those releases at all. Checking which enhancement package you are actually on is the first thing to do, because it decides whether you have a deadline ahead of you or one behind you.
The deadline matters less for the software itself than for what stops arriving with it. An unsupported ECC keeps running perfectly well the day after maintenance ends — what you lose is the stream of legal and regulatory updates: statutory payroll changes, tax rate revisions, e-invoicing mandates and country-specific reporting formats. In markets like India, Brazil or Saudi Arabia, where e-invoicing rules change on government timelines rather than yours, that is the constraint that actually forces the date.
Beyond compliance, S/4HANA replaces batch-era architecture with real-time analytics on in-memory HANA, a Fiori-first interface, and a simplified data model that removes the reconciliation layer between Finance and Controlling. Companies that start now can re-platform deliberately and absorb the change over two budget cycles. Those that wait will be buying scarce consultants in a seller's market and compressing testing to fit a fixed date.
The deadline gets the project on the agenda. These are the arguments that get it funded.
The universal journal removes the reconciliation step between FI and CO. Period-end no longer waits on reconciliation between the two, which is where a large part of a slow close usually sits. How much time you actually recover depends on how much of your close is reconciliation versus approvals and accruals.
Operational reporting runs directly on the transactional tables through CDS views, so stock, margin and order positions are current rather than as-of-last-night. A good deal of the custom BW extraction layer built over the ECC years simply stops being necessary.
Fiori apps are role-based and work on a phone, which matters most for the people who never wanted to learn SAP GUI — warehouse staff, plant supervisors, approvers on the road. Approval backlogs tend to be the first visible win.
A migration is the one moment when the business will agree to retire dead custom transactions, duplicate vendor records and obsolete interfaces. Most ECC estates carry a decade of accumulated exceptions that nobody has authority to remove in normal times.
Capabilities that needed bolt-ons around ECC — embedded analytics, cash management, advanced ATP — are part of the core in S/4HANA. Every satellite retired removes a licence, an interface and a system nobody wanted to own.
SAP's investment in embedded AI, Joule and the Business Technology Platform targets S/4HANA. ECC receives corrections, not capability. Staying put does not hold your position — it widens the gap every release.
Work backwards from the date your regulatory updates stop, not from the date support ends.
Readiness check, custom code analysis and a path decision can be done inside a quarter. Starting here means a normal project with normal testing, and consultants who are not yet being bid against three other clients.
Applies to enhancement packages 6, 7 and 8. Legal and regulatory updates stop; the system keeps running but statutory changes are no longer delivered. For a multi-country group this is normally the true hard stop. Releases without an enhancement package, and EhP 1–5, passed this point on 31 December 2025.
Priced at two additional percentage points on the standard support rate, and offered for enhancement packages 6 to 8 only. It buys time, not capability. After it ends, customer-specific maintenance is the only remaining option.
SAP ERP, private edition, transition option covers 2031 to 2033, but it is narrow: bookable from 2028, aimed at SAP’s largest and most complex customers, and conditional on committing to RISE with SAP, running or moving to HANA as the database, and taking the accompanying success plan. It is priced at an uplift. Treat it as a commercial arrangement for a small group, not as a general extension of the deadline.
SAP supports three formal migration approaches, each with distinct trade-offs:
Convert the existing ECC in place to S/4HANA, preserving data, customisations and configuration. The fastest route, and the one that carries your technical debt with it.
Stand up a fresh S/4HANA system, re-design processes on SAP Best Practices, and migrate only the master and open transaction data you actually need.
Selective data transition — move chosen company codes, plants or fiscal years, and archive or harmonise the rest. Used where one size genuinely does not fit all.
The same decision, laid out on the axes that actually separate the three paths. Scroll horizontally on a narrow screen.
| Dimension | Brownfield conversion | Greenfield re-implementation | Hybrid selective transition |
|---|---|---|---|
| Core idea | Convert the system you have, in place | Build clean, migrate what you need | Move chosen slices, archive the rest |
| Typical duration | 5–9 months | 8–14 months | 12–24 months |
| Typical budget | $80k–$250k | $150k–$450k | $350k–$900k |
| Historical data | All of it carries across | Open items and balances only | You choose, per company code or year |
| Process re-design | Little to none | Full re-design on Best Practices | Selective — re-design where it pays |
| Custom code | Carried forward, then remediated | Rebuilt only where still justified | Mixed — retained per scope |
| Technical debt | Comes with you | Left behind | Reduced where you choose |
| Business disruption | Low — users see a new UI, same process | High — new processes and new UI | Moderate, and staged by wave |
| Change management load | Light | Heavy — the real cost driver | Moderate, repeated per wave |
| Technical downtime | 24–72h; under 12h with DoDMO | Cutover weekend per wave | Cutover weekend per wave |
| Primary tooling | SUM with DMO | SAP Activate, Migrate Your Data | SAP SLO, SNP BLUEFIELD, Natuvion DCS |
| Rollback story | Restore from backup — rehearse it | Legacy stays up until you cut over | Legacy stays up per wave |
| Best suited to | Stable, well-documented ECC estates | Heavy technical debt, appetite for change | Multi-national groups, carve-outs, M&A |
| Main risk | Inheriting problems you meant to fix | Scope creep during re-design | Complexity and tooling licence cost |
Preserves 80–90% of the legacy ECC configuration, custom ABAP, and data. Uses SAP SUM DMO (Software Update Manager with Database Migration Option) to perform the database migration and the S/4HANA upgrade in a single maintenance window.
Best for: mature ECC installs with heavy customisation, stable processes, and no appetite for organisational change alongside a technical migration.
Duration: 5–9 months typically. Cost: $80k–$250k depending on scope and customisation depth. Technical downtime: 24–72 hours, reducible below 12 with Downtime-Optimized DMO.
Risks: carries forward technical debt; custom code must pass the S/4HANA simplification checks; the unified journal (ACDOCA) rewrite is non-trivial and the Business Partner conversion is mandatory.
Rehearse this: run at least three full conversion cycles on copies of production. The first tells you what breaks, the second tells you how long it takes, the third proves the runbook. Teams that budget for one dress rehearsal almost always need a fourth attempt on the night.
A fresh S/4HANA implementation built on SAP Best Practices and the SAP Activate methodology. Legacy processes are reviewed and re-designed; only essential master data and open transactions carry across.
Best for: businesses that want to simplify processes, adopt a Fiori-first experience, move to a cloud-first deployment, and shed a decade of accumulated technical debt.
Duration: 8–14 months for mid-to-large enterprises. Cost: $150k–$450k depending on scope and the number of country rollouts.
Risks: the cost sits in change management rather than technology. Re-design invites scope creep, and every re-designed process needs the business to agree, document and then actually adopt it. Freeze the process design before the build starts.
Often overlooked: you still have to answer what happens to twenty years of history. Most greenfield projects keep the old ECC read-only for a statutory retention period, or archive to a separate store — both cost money that rarely appears in the original business case.
Combines the speed of brownfield with the cleanup benefits of greenfield. Tools such as SAP SLO (System Landscape Optimization), SNP BLUEFIELD and Natuvion DCS let you migrate selectively — specific company codes, fiscal years or plants — while harmonising or archiving the rest.
Best for: large multi-national groups with divestitures, carve-outs or heavy historical data that should be archived rather than migrated, and groups where one region wants re-design while another needs continuity.
Duration: 12–24 months across waves. Cost: $350k–$900k, including third-party tooling licences that brownfield and greenfield do not need.
Risks: the most complex path to govern. Running two landscapes during the wave programme means duplicated interfaces, reconciliation between old and new, and a longer period where the group reports out of two systems.
SAP Activate is the standard methodology for all three paths. The phase names stay the same; what changes is how much weight each one carries.
SAP Readiness Check 2.0, custom code impact analysis, interface and add-on inventory, HANA sizing. Ends with a recommended path and a sized roadmap. This is the phase we run free of charge.
Project setup, governance, landscape plan, and the sandbox conversion. The first technical conversion happens here, not later — it converts unknowns into a defect list while there is still time to act on it.
Fit-to-standard workshops against SAP Best Practices. Every gap is logged and each one gets a decision: adopt the standard, configure, or build. Brownfield projects run a shorter version focused on simplification items.
Configuration, custom code remediation, data migration cycles, integration build, and successive test waves — unit, string, integration, and at least two mock cutovers with full data volume.
Final dress rehearsal, cutover execution, hypercare staffing and the go/no-go decision. The runbook should be minute-by-minute and already proven twice before this phase begins.
Hypercare for four to eight weeks, then steady-state application management. S/4HANA moves to an annual release cadence, so upgrade planning becomes a routine activity rather than a project.
Before choosing a path, run the SAP Readiness Check 2.0 (a free SAP tool) and layer in these reviews:
Most ECC estates carry tens of thousands of lines of custom code. Very little of it needs a rewrite — but you cannot know which part until you measure.
The majority of custom objects compile and run unchanged. Reports over tables that still exist, user exits on unchanged interfaces, and most utility programs come across without intervention.
Field length extensions (material number to 40 characters), replaced tables, and selects against aggregates that no longer exist. Individually minor, collectively the bulk of the remediation effort.
Code touching the Finance data model, output management, or anything that wrote directly to tables now replaced by the universal journal. These need a developer who understands both the old and new model.
Usage statistics almost always show a fifth to a third of custom transactions have not been executed in twelve months. Retiring them is the cheapest remediation available, and the only one that reduces future cost.
ATC running the S4HANA_READINESS check variant against your code base, cross-referenced with SCMON or UPL usage data so effort is spent on what people actually run.
Immediately, and independently of the path decision. Custom code analysis needs no system copy, blocks nothing, and the retirement list is useful whichever route you eventually take.
Indicative planning ranges for offshore delivery from India, to sanity-check a budget before a proposal exists. Your actual figure depends on database size, custom code volume, country rollouts and add-ons — all of which the readiness assessment measures. These are not a quotation.
| Scope | Path | Timeline | Budget (USD) | Core team | Technical downtime |
|---|---|---|---|---|---|
| Mid-market 50–200 users, 1 country | Brownfield | 5–7 mo | $80k–$150k | 6–10 people | 24–48h |
| Mid-market 50–200 users, 1 country | Greenfield | 7–10 mo | $130k–$260k | 8–12 people | Cutover weekend |
| Enterprise 200–1000 users, 2–5 countries | Brownfield | 8–12 mo | $180k–$350k | 12–18 people | 48–72h |
| Enterprise 200–1000 users, 2–5 countries | Greenfield | 12–16 mo | $300k–$600k | 18–28 people | Cutover weekend per wave |
| Global 1000+ users, 10+ countries | Hybrid | 18–24 mo | $600k–$1.2M | 30–50 people | Per wave |
Indicative split of a conversion budget, to show where money goes rather than to price your project. The line most often missing from a business case is the last one.
| Workstream | Share of budget | What drives it up |
|---|---|---|
| Functional configuration & fit-to-standard | 20–30% | Number of country rollouts and how far processes deviate from Best Practices |
| Custom code remediation | 15–25% | Size of the custom estate and how much of it touches Finance |
| Data migration & cleansing | 15–20% | Master data quality, duplicate customers and vendors, open-item volume |
| Testing & mock cutovers | 15–20% | Number of interfaces and how many full-volume rehearsals you run |
| Integration & interfaces | 10–15% | Count of external systems, EDI partners and bespoke middleware |
| Infrastructure & HANA licensing | 5–15% | Database size after archiving; deployment model chosen |
| Change management & training | 10–15% | Greenfield roughly doubles this against brownfield — and it is the line most often cut first, then paid for twice |
Six failures we see repeatedly. Every one of them is cheaper to prevent than to discover during cutover.
Most ECC clients carry more than 10,000 objects of custom ABAP, and every one needs an S/4HANA compatibility review. Teams that guess instead of running ATC are usually wrong by a factor of two.
The universal journal is the biggest functional change in Finance. Run two to three mock cutovers with full data volume and let the finance team close a period in the converted system before go-live.
Customer and vendor masters collapse into a single Business Partner, and it is mandatory. Handle the duplicates and incomplete records months before go-live, not during cutover week.
Planning behaviour changes and manufacturing teams need explicit retraining. Planners who trust the old run schedule will not trust the new numbers unless they are walked through why they differ.
The move from SmartForms and SAPscript toward Adobe Forms and BRF+ touches every invoice, delivery note and purchase order. Inventory every print form early; there are always more than anyone expects.
PI/PO flows, IDocs, EDI partners and APIs must be retested end to end, with the partner on the other side. Interfaces that pass in isolation routinely fail on the first real three-way exchange.
Certified SAP consultants with offshore delivery from India, working to the same SAP Activate phases described above.
Readiness Check 2.0 analysis, custom code impact review and a sized migration roadmap in about three weeks, at no cost and with no obligation to continue.
Functional leads in your timezone for workshops and sign-off, with build and remediation delivered from Guntur. You are told which work sits where before the contract is signed.
Each SAP Activate phase is quoted and signed separately, so you can stop at a phase boundary. Nobody is asked to approve a two-year budget on a three-week understanding of the scope.
All custom developments, remediation work and documentation are handed over in your repositories. No vendor lock-in on the work you paid for.
The rules we apply in the first readiness workshop. Most organisations recognise themselves in one of these three within about ten minutes.
Your ECC configuration is stable, customisation is well documented, and the business is not asking to change how it works. It is also the pragmatic answer when 2027 is the only real driver — convert first, then schedule the cleanup as its own programme rather than bolting it onto a deadline.
You want to re-design processes, move to a cloud-first deployment, or your ECC carries so much technical debt that converting it would simply relocate the problem. Requires genuine appetite for change — the cost sits in change management, not technology.
You run multiple company codes with genuinely different needs, or a divestiture or acquisition is in progress. Lets one region re-design while another keeps continuity, at the price of the most complex programme of the three to govern.
That is the normal answer, and it is what the readiness check is for. The custom code and data-quality numbers usually make the decision obvious once they are on the table.
Our free SAP readiness assessment covers Readiness Check 2.0 analysis, a custom code impact review and a sized migration roadmap, in about three weeks. No system copy required.
The questions that come up in almost every readiness workshop.
We are not the biggest SAP partner you could hire. These are the reasons clients choose us over one that is.
The same SAP Activate methodology, the same certified consultants, delivered from Guntur. That is the entire reason the budget ranges on this page look different from a tier-one proposal for identical scope.
The people who scope your migration are the people who deliver it. No handover to a delivery centre you never met, and no named consultant on the proposal who disappears after signature.
The readiness assessment is free and produces something you can act on regardless of who you hire — a Readiness Check analysis, a custom code impact review and a sized roadmap. If the answer is that you should stay on ECC until 2027, we will say so.
Custom developments, remediation work and documentation are handed over in your repositories, and your team is trained to run the system rather than kept dependent on us for routine changes.
Most SAP estates are surrounded by eCommerce platforms, carrier APIs, payment gateways and warehouse systems. We build those integrations as our day job, so the interface inventory is not the part of your migration that surprises everyone.
More than 50 clients across 15+ countries, on ERP, SAP and integration work. Long enough to have seen migrations go wrong, which is what the pitfalls section on this page is drawn from.
Three pages cover SAP here, each answering a different question. Whichever you landed on, the other two are one click away.
We offer a Free Proof of Concept — a working build tailored to your business in 2–3 weeks, with zero upfront cost. ERP, SAP, Flutter, or integrations.
