The first thing to say about Dynamics 365 implementation cost is that the question contains two products with an order of magnitude between them. The second is that most blowouts are built into the deal before anyone writes code. Here are the bands as we see them, and the decisions that move you within them.
Business Central implementations for a single Australian entity with conventional processes typically land as low-to-mid six-figure engagements, delivered in a quarter or two by a capable partner. Complexity pushes toward the top of that band and beyond: manufacturing depth, many integrations, heavy data migration.
Finance and Operations programmes start around the high six figures and rise with entities, geographies and integrations. Multinational, multi-entity programmes routinely run into seven figures and are measured in quarters to years. That is not partner gouging. F&O programmes carry environment strategy, data migration rehearsal, regression machinery for One Version, and programme governance that Business Central projects rarely need at the same intensity.
Licensing follows the same shape, with F&O running at several times BC's per-user rate before the operations, device and attach licences that enterprise deployments accumulate. If you are still deciding between the products, read our selection guide first. Choosing wrongly is the most expensive mistake available in this domain, because there is no upgrade path between them.
Four decisions dominate. Customisation discipline comes first: every extension you build is something to regression test forever, and the gap between a configure-first implementation and a customise-by-default one compounds across the life of the estate. Data migration scope comes second. Bringing open balances and clean master data is a project. Bringing ten years of transactional history is a much bigger project with little operational return, and we have made that argument in full. Integration count is third, because each system that touches the ERP brings design, build, testing and a permanent maintenance obligation. The fourth is decision-making bandwidth in your own business. Programmes stall waiting for process owners far more often than they stall waiting for consultants, and a stalled programme burns money at close to full rate.
Budget for ongoing support and continuous-update absorption at roughly 15 to 25 per cent of the implementation cost annually, depending on how much of the estate is customised and how much you run in-house. A disciplined estate sits at the low end. What good support looks like after hypercare is its own topic.
Ask what assumptions the estimate stands on. How many process workshops, how many data migration cycles, how many integrations, and what testing effort the client is expected to staff. A cheap quote is usually a quote with the assumptions left out, and the difference comes back later as variations. Ask who actually delivers, too: the team in the proposal, or a different one after signature.
If you want a number with reasons attached rather than a brochure figure, our Dynamics 365 practice runs scoping assessments that produce exactly that: the estimate, the assumptions underneath it, and the decisions that would move it. A consultant who has run these programmes replies within one business day.