SAP to Dynamics 365: What Every SAP User Must Know Before the 2027 Deadline

The short answer

If you run SAP ECC, 2027 is the date that forces a decision, not the date that ends your system. The real question is what you want your ERP to be for the next decade. For mid-market companies and groups already invested in Microsoft, Dynamics 365 is a credible alternative to the S/4HANA conversion, and the planning window is narrower than most programmes assume.

SAP remains a powerful choice for very large, deeply complex global enterprises, and we say so plainly. But a large number of organisations on ECC are not that company. They are mid-sized businesses and regional groups with a Microsoft-centred IT estate, a stack of custom ABAP built over fifteen years, and a finance team that spends its month-end in spreadsheets. For them, the end of mainstream maintenance is a natural moment to ask whether the next ERP should be a like-for-like SAP move or something lighter, faster and more connected to the tools people already use.

This guide explains what the 2027 date actually means, the five reasons organisations move from SAP to Dynamics 365, when staying with SAP is the right call, how SAP modules and data map to Dynamics 365, the options open to an ECC user, and how to plan backwards from the deadline. Dates, prices and licence terms change, so confirm current terms with SAP and Microsoft before you decide.

What the 2027 deadline actually is

SAP has announced the end of mainstream maintenance for SAP ECC 6.0 at the end of 2027. That is the date in the headlines. The detail matters, because it changes how urgent your decision is.

• Mainstream maintenance ends at the end of 2027. After it, standard support and updates change.
• SAP has also announced options beyond that date: extended maintenance for a limited period at a higher fee, and further options linked to its cloud subscription offers. The terms depend on your contract and your release, so ask your SAP account team for them in writing.
• The ECC to S/4HANA move is not a simple upgrade. It is a conversion or a new implementation, with a data model change, a new user interface and custom code that has to be remediated. Many organisations treat it as a re-implementation.
• Because the move is a project either way, ECC users are in effect re-evaluating their ERP from scratch, whether they admit it or not.

This is what people mean by a burning platform. The system will not stop on 1 January 2028. But the cost of staying, the pressure from auditors and insurers, the difficulty of hiring ECC skills and the sheer length of the migration all push the decision forward. As of late October 2026, about fourteen months remain before the end of 2027. A programme that has to be live by then needs its decision made soon.

Five reasons organisations move from SAP to Dynamics 365

The decision is rarely based on one factor. It is usually a combination of cost, agility, ecosystem fit, timing and the weight of legacy customisation.

Reason one: cost you can predict

Total cost of ownership is the most cited driver. Microsoft publishes list prices for Dynamics 365, where SAP enterprise agreements are typically custom-quoted. Published prices make it easier to build a business case without waiting for a negotiation.

• Licensing: compare the per-user and per-module position on both platforms for your actual user mix, including the light and occasional users who make up most of an ERP population. Ask for written quotes on both sides.
• Infrastructure: if your ECC runs on-premises, add hardware, hosting, database licences, patching, disaster recovery and the people who run them. Dynamics 365 is delivered as a cloud service, which moves much of that to an operating expense.
• Talent: specialist ABAP developers and SAP basis administrators are scarce and expensive. Developers for Dynamics 365 and the Power Platform are generally easier to find and cheaper to retain, and many changes can be made by business analysts without code.
• Upgrades: ECC upgrades and the S/4HANA conversion are projects in themselves. Dynamics 365 receives regular updates from Microsoft, so the cost of staying current becomes small and continuous rather than large and occasional.

We deliberately do not quote a saving percentage in this article. Savings depend on your user mix, your customisation, your hosting and your negotiation, and a number from another company's project is not your number. Put both options on a five-year line with the same assumptions, and let the result stand on its own. See our total cost of ownership framework.

Reason two: agility and time to value

Many organisations leave SAP because they want to escape the rigidity and the length of the programmes.

• Phased scope: Dynamics 365 is modular. You can implement finance and supply chain first and add HR, CRM or analytics later, rather than adopting a big-bang scope.
• Speed: partners commonly quote shorter timelines for Business Central than for Finance and Supply Chain Management, and both are generally shorter than a full S/4HANA programme. Treat any range as indicative, because it depends on entities, countries, data quality, customisation and your own team's availability.
• Acquisitions: groups that buy companies often find it easier to onboard an acquired business onto a standard Dynamics 365 template than to integrate it into a heavily customised SAP landscape. See multi-country deployments: one template.
• Fit the business to the product where it makes sense, and extend only where you truly differ. That is the opposite of the custom-everything habit that built many SAP estates.

If you are weighing the two Dynamics 365 finance products, our guide to Business Central or Finance and Operations explains how entity count, integration load and regulatory reporting decide it.

Reason three: native fit with the Microsoft ecosystem

If your people already live in Outlook, Teams, Excel and SharePoint, the value of Dynamics 365 rises sharply.

• Work where people already are: approvals in Teams and Outlook, data in Excel, documents in SharePoint, one sign-in through Microsoft Entra ID.
• One platform: ERP, CRM, analytics and automation share the Microsoft cloud. Power BI, Power Apps and Power Automate let business users build reports, small applications and workflows without specialist ABAP developers. See Power Platform and Power BI.
• Data foundation: Dynamics 365 data can feed Microsoft Fabric for analytics, without the extract-and-reload cycle that separate business warehouses often need.
• AI: Copilot capabilities are built into Dynamics 365 applications, and agents can take on bounded, high-volume work such as summarising exceptions. Check current licensing, because some capabilities and agents are usage-based. We describe where agents earn their keep in Agentic ERP without the hype.

Reason four: the burning platform

For many ECC users the trigger is simply timing. When the conversion to S/4HANA is itself a new implementation, the choice is no longer between staying and moving. It is between two moves.

• Option A: convert ECC to S/4HANA, keeping the SAP data model and a large share of the custom code, after remediation.
• Option B: implement a new platform, with a clean design and a controlled migration of balances and open items.

Seen that way, Dynamics 365 is a fair and viable alternative for the organisations it fits. The decision should be made on fit, cost and risk, with the 2027 date as the constraint rather than the reason.

Reason five: the weight of legacy customisation

Highly customised SAP systems become difficult and expensive to extend. Every Z-program, user exit and bolt-on is something your team must understand, test and carry through the next change.

• A move to Dynamics 365 is a chance to retire customisation that no longer serves the business. Much of it was written for a process that changed years ago.
• What remains is rebuilt in the way that survives updates: standard configuration first, Power Platform for workflows and small apps, and extensions only for genuine differentiation. See clean core and dual-write.
• The result is a system that stays close to standard, so Microsoft's regular updates do not become a project of your own.

When staying with SAP is the right answer

We would rather tell you now. SAP is often the right answer for very large, complex global enterprises with deeply embedded industry solutions, thousands of users, mission-critical processes that are tightly coupled to SAP-specific functionality, and a team that has the scale and skills to run it.

It is also the right answer when an S/4HANA programme is already well under way and on track, when your industry depends on an SAP solution without an equivalent, or when a conversion is close to complete. Switching platforms mid-flight rarely saves money.

If your landscape is between those extremes, with a mid-sized footprint, a Microsoft-centred IT estate and a long tail of customisation, then it is worth putting both options side by side before committing.

How SAP maps to Dynamics 365

This is the table we draw in the first workshop. It is a starting point: the right target depends on your processes, not only the module name.

Not every SAP module has to move on day one. Some organisations move finance and supply chain first and run a specialist SAP module for a time, connected by a designed integration. That is a legitimate way to reduce risk, as long as the integration is designed rather than improvised.

How the data actually moves

There is no push-button converter between SAP and Dynamics 365. The data models differ, so the work is extraction, transformation, loading and proof. We migrate balances and open items, and archive closed history in a form finance can search and auditors can read.

Table names above are examples to show the kind of source. Your landscape, release and custom fields decide the real extraction scope, which we confirm in discovery. See also ERP cutover and data migration.

The options open to an ECC user

Staying put, converting, moving to Dynamics 365 or splitting the estate are all legitimate. What matters is choosing on purpose.

Two-tier arrangements deserve more attention than they get. Many groups move their smaller entities, or their newly acquired ones, to Dynamics 365 first, prove the template, and decide later about the core.

Planning backwards from the deadline

If you decide to move, work backwards from the date you must be live. The sequence is the same for every programme; the durations are yours to confirm.

• Decide: agree the options, the business case and the target scope. Name an executive owner.
• Discover and design: inventory what SAP does today, including custom code and interfaces, and settle the blueprint, the entity structure and the chart of accounts. See Dynamics 365 Solution Design and Architecture.
• Build and migrate in rehearsals: extract, transform and load several times, and reconcile each time to SAP. The business signs off the reconciliation.
• Test and train by role: scenario tests, user acceptance, and training before cutover rather than after.
• Cut over at a period boundary: freeze SAP, load the final delta and opening balances, reconcile, and take a go or no-go decision.
• Hypercare and retire: stay close through the first closes, keep read-only access to SAP for audit and retention, and agree the retirement date.

Add a buffer. The programme that lands comfortably before the deadline usually started early, decided scope quickly and kept customisation low. Check the commercial position of your SAP contract too: renewal dates, notice periods, and your rights to export data.

Mistakes we see

• Lift and shift: rebuilding SAP's quirks inside Dynamics 365. Use the move to simplify.
• Migrating everything: loading closed history slows the project. Load balances and open items, archive the rest.
• Keeping the old chart of accounts: complexity carried into a new ledger.
• Underestimating data quality: duplicate vendors and inconsistent units are found late. Profile the data in discovery.
• Treating training as a slide deck: if the people who post have not rehearsed their role, delay the cutover.
• Letting the deadline set the scope: a date is a constraint, not a design.
• No independent review: a second pair of eyes at blueprint, build and go-live is cheaper than a failed launch.

Is it time? Twelve questions for your next steering meeting

A rule of thumb of our own, not a scientific score. Answer yes or no.

• Are we on SAP ECC today?
• Is our S/4HANA conversion not yet started or not yet funded?
• Is a large share of our ERP cost in custom code, infrastructure and specialist contractors?
• Do we run fewer than a few thousand ERP users?
• Is our IT strategy centred on Microsoft 365, Teams and Azure?
• Do finance teams build the board pack from exports?
• Do we acquire or plan to acquire businesses that need onboarding quickly?
• Is one person or one contractor the only one who understands our SAP customisation?
• Do our users have to leave their normal tools to approve or query ERP data?
• Are we paying for modules few people use?
• Do we want a lighter, more standard system with regular updates?
• Would a phased move, one entity or module at a time, reduce our risk?

If you answer yes to four or more, a structured platform review is worth doing. If you answer yes to most of the first three and few of the rest, an S/4HANA conversion may suit you better.

Where to start

Start with a discovery workshop on your SAP estate. You leave with an inventory of modules, custom code, interfaces and data volumes, a proposed Dynamics 365 target, a fit-gap against standard, and a plan with the main risks named. If you have already chosen a path, an independent architecture assessment tests it before you commit.

If you are not ready to decide, that is fine. The workshop is useful either way, because it shows what a move would involve and what staying would require. This article is general information, not legal, financial or licensing advice. Confirm SAP maintenance dates and licence terms with SAP, and Dynamics 365 capabilities and licence terms with Microsoft.

On SAP ECC and weighing the 2027 deadline? Book a SAP-to-Dynamics 365 discovery workshop. Book a consultation