Cloud migration is often sold on cost reduction. It is fairer to describe it as a change in cost shape — from a large purchase every few years to a monthly bill that moves with usage. Whether the total falls depends almost entirely on what you do after the migration.
Why lift-and-shift often costs more
On-premise servers are typically sized for peak load and run at low utilisation the rest of the time. That waste is invisible because the hardware is already paid for. Move the same specification to the cloud and the waste becomes a line item you pay for every month.
Lift-and-shift is still frequently the right first move — it gets you out of an ageing server room and buys time. But it should be planned as a stage, with the optimisation work funded from the start rather than hoped for later.
Where the savings are
- Switching off what is idle. Development and test environments rarely need to run overnight or at weekends.
- Right-sizing after measurement, not from the old specification sheet.
- Committed-use pricing once your baseline is genuinely understood — usually after two or three months of real data.
- Managed services replacing self-run databases, where the saving is in staff time rather than the invoice.
The costs people forget
Data transfer out of the provider is the one that surprises most teams — it barely registers in planning and then appears every month. Inter-region traffic, cross-zone replication, and logging volume are the others. None is a reason not to migrate; all are reasons to model the bill before committing.
Plan the operating model, not just the move
Cloud spending is decentralised by design: any engineer can create a resource. Without tagging, ownership and a monthly review, costs drift upward quietly. The organisations that save money are the ones that assign someone to look at the bill every month and ask what changed.
A realistic expectation
Expect costs to rise during migration and for a period afterwards. Expect them to fall below the old run rate only once optimisation work is done — and only if someone owns it. Budget for that phase explicitly, because it is the phase that delivers the number in the business case.
