18 Months to the SAP ECC Cliff — and Half of Customers Still Haven’t Moved.

Eighteen months until SAP ECC end of support is not much runway considering that most SAP ECC migrations take 18 to 36 months. The deadline arrives on December 31, 2027, and anyone starting the clock today is already working against it.

Today, we are exploring the decision framework that legacy SAP system holdouts need before the calendar makes the choice for them.

The Clock on Every Legacy SAP System

Mainstream maintenance for SAP ECC ends on December 31, 2027, for the vast majority of organizations still running it. For everyone still within the mainstream window, SAP is offering Extended Maintenance through December 31, 2030. However, this only restores security patches and legal or regulatory updates; it does not add new functionality.

For organizations planning a full migration rather than a maintenance extension, the typical S/4HANA project runs 18 to 36 months depending on data volume, degree of customization, and whether the organization rebuilds its processes from scratch or converts its existing system in place. This means that anyone beginning this project after mid-2026 has little room for the schedule slippage that large ERP projects routinely experience.

Why Nearly Half of ECC Customers Have Not Moved

Gartner estimates that only 39 percent of the roughly 35,000 organizations running SAP ECC 6.0 had migrated to S/4HANA by the end of 2024. The firm projects that close to half will still be running ECC when the December 2027 deadline arrives.

More than a third are expected to remain on the legacy SAP system even in 2030, according to Gartner’s analysis reported by CIO.com.

The barriers behind that hesitation are consistent across industries.

• Customization depth: Many ECC environments carry a decade or more of custom code, user exits, and workarounds built around processes the original vendor never anticipated.
• Cost range: Migration budgets vary enormously, from roughly $2 million for a contained environment to more than $1 billion for a large, heavily customized enterprise.
• Competing priorities: IT leaders are weighing the ECC deadline against other capital projects, and the deadline alone rarely wins the budget argument on its own.
• Uncertainty about fit: Some organizations are not convinced S/4HANA is the right long-term platform for their industry or footprint, and would rather pause than commit.

Four Paths Through SAP End of Maintenance

Every organization currently running SAP ECC has effectively four options, and none of them is free of cost or risk. The right choice depends on system complexity, budget cycles, and how confident the organization is that S/4HANA is the correct next step.

• Migrate to S/4HANA Now – Migrating now locks in the longest runway before the 2027 deadline and gives the organization the most control over sequencing and testing. It is often the right path for organizations whose ECC environment is heavily customized around manufacturing ERP software requirements, such as complex bills of material or shop floor integration, where a rushed conversion later would carry more risk than an orderly one now.

• Pay for Extended Maintenance Through 2030 – Extended Maintenance buys three additional years at a modest premium and is a reasonable choice for organizations that need more runway to build the internal business case. It does not solve the underlying problem, and it is only available to organizations still within SAP’s mainstream support window.

• Adopt Third-Party Support – Independent support providers such as Rimini Street offer coverage for SAP ECC well beyond SAP’s own maintenance windows, in some cases through 2040, typically at a substantial discount to SAP’s standard fees. Third-party support keeps the current system running and preserves existing perpetual licenses as owned assets, but it forecloses access to new SAP innovation and can complicate a future migration if the organization eventually does move to S/4HANA.

• Use the Deadline to Re-Evaluate Fit – For some organizations, the honest answer is that ECC has been outgrown by the business itself. A merger, a divestiture, or a shift in operating model can mean the process design baked into a decade-old ERP configuration no longer matches how the company runs today. That is a reason to bring in an independent ERP selection consultant before committing to any migration path, so the deadline becomes an opportunity to confirm fit.

Expert Insight

Our ERP selection consulting team has found that organizations who treat a platform deadline as a pure infrastructure decision often skip the fit question entirely, and later discover the new platform inherited the same process gaps as the old one. Working with an independent ERP advisor before the technical decision is made keeps the two questions from being collapsed into one.

Building Your Decision Framework Before the Deadline Arrives

Deciding among these four paths does not require a lengthy study, but it does require answering a short set of questions in a deliberate order.

• Confirm Your Actual Deadline – Confirm which SAP ECC version the organization runs today and check it against SAP’s published support schedule. Some organizations on older versions are already past their mainstream window and need to move faster than the 2027 headline suggests.

• Quantify the Cost of Each Path – The four paths carry genuinely different cost structures, not just different price tags. A fit reassessment is the smallest near-term cost of the four, but it defers the larger decision rather than resolving it. Compare all four on the same time horizon rather than against next year’s budget line alone.

• Test the Business Case Against Actual Operations – For organizations whose ECC environment carries significant supply chain functionality, bring in SCM consulting support early enough to confirm which processes genuinely need to move and which were built around a supply chain structure the company no longer has.

• Choose a Path and Set a Governance Checkpoint – Once a path is chosen, set a checkpoint at the six-month mark to confirm the assumptions behind it still hold. Vendor pricing, internal staffing, and business priorities can all shift over an 18 to 36 month project, and the checkpoint is what catches drift before it becomes a crisis.

Learn More About SAP ECC’s End of Support

The 2027 deadline is real, but it does not have to dictate the outcome. Organizations that treat it as a forcing function for a genuine strategic review, rather than a countdown to panic, tend to make better decisions regardless of which of the four paths they choose.

Panorama’s independent ERP services team advises exclusively as a vendor-neutral consultancy, without referral fees from SAP or any other software provider. Contact us below to learn more.