Compare cloud and on-premise costs honestly, and build a case your board will sign.
We build a total cost of ownership model that sets your current on-premise costs against running the same workloads on AWS, Microsoft Azure or Google Cloud. The result is a business case with clear assumptions, a multi-year cash flow view and the non-financial benefits your leadership needs to decide.
Why cloud business cases go wrong
Many cloud business cases compare a server's purchase cost with a monthly cloud bill and stop there. That misses the real on-premise costs, such as power, space, hardware refresh, support contracts, backup and staff time, and it often assumes cloud resources are sized exactly like today's servers. The result is either a case that is too optimistic and loses credibility after go-live, or one that is too pessimistic and stops a sensible move.
Hidden on-premise costs
Facilities, hardware refresh cycles, software support and administration time are rarely in one place. We gather them so the comparison is fair.
Over-sized cloud estimates
Sizing cloud resources on allocated capacity rather than actual use inflates the cost. We size on measured utilisation.
Licensing surprises
Moving Windows Server, SQL Server, Oracle or SAP licences to cloud has rules. Getting them wrong can change the case completely.
Timing of spend
Migrations happen in waves, so on-premise and cloud costs overlap for a period. The case must show that overlap, not just the end state.
What we do
We produce a business case grounded in your own data, with every assumption written down and open to challenge.
Current cost baseline
We collect hardware, data centre, licence, support, network and staff costs for the systems in scope. Where figures are missing we agree reasonable assumptions with your finance team.
Right-sized cloud costing
We use utilisation data from discovery tools to size each workload on AWS, Azure or Google Cloud. We then cost it with each provider's own pricing calculators and assessment tools.
Licence review
We check how your existing Microsoft, Oracle, SAP and other licences can be reused in the cloud. We model licence-included and bring-your-own-licence options where both are allowed.
Commitment and purchasing options
We show how reserved capacity, savings plans and existing cloud commitments affect the long-term cost. We also flag where marketplace buying can help.
Multi-year cash flow
We model costs year by year through the migration, including the overlap while both environments run. We can include net present value using your own discount rate.
Non-financial benefits
We capture benefits such as resilience, security, speed of delivery and avoided hardware refresh. These sit alongside the numbers so the decision is balanced.
How it works
- 1
Scope and data request
We agree which systems are in scope and send a structured data request. Finance, IT and procurement each provide their part.
1 week - 2
Baseline and discovery
We build the on-premise cost baseline and collect utilisation data from your servers and databases. Gaps are filled with agreed assumptions.
2 to 3 weeks - 3
Cloud modelling
We size and cost the target environment on the chosen cloud or clouds. We run scenarios for different migration timings and purchasing options.
2 weeks - 4
Review with finance
We walk your finance team through every assumption and adjust where they disagree. This is where the case earns its credibility.
1 week - 5
Final business case
We deliver the model, a written case and an executive summary. You can use them for board approval or budget planning.
1 week
Native costing tools on each cloud
We use each provider's own tools so your figures line up with what the provider will quote and bill.
| Need | AWS | Microsoft Azure | Google Cloud |
|---|---|---|---|
| On-premise versus cloud TCO | Migration Evaluator | Azure Migrate business case | Migration Center cost estimates and TCO reports |
| Service cost estimates | AWS Pricing Calculator | Azure pricing calculator | Google Cloud Pricing Calculator |
| Commitment options | Savings Plans, Reserved Instances | Azure savings plan for compute, Azure Reservations | Committed use discounts |
| Licence reuse | Bring your own licence, AWS License Manager | Azure Hybrid Benefit | Bring your own licence on sole-tenant nodes |
| Tracking costs after go-live | AWS Cost Explorer | Microsoft Cost Management | Cloud Billing reports |
Business cases for SAP
SAP business cases are different because the choice is not just which cloud, but who runs the system. Under RISE with SAP, SAP runs the infrastructure and technical operations on your chosen hyperscaler under a single subscription, so infrastructure, basis operations and support move into one contract. If you run S/4HANA or ECC yourself on AWS, Azure or Google Cloud, you pay the cloud provider directly and run operations with your team or ours. We model both so you can compare like with like.
- We compare RISE with SAP against self-managed S/4HANA on your own cloud subscription, on the same scope and timeline.
- We include the cost of staying on ECC, such as extended maintenance after 2027 and ageing hardware.
- We separate one-off transformation costs from ongoing run costs so each option is clear.
- Google Cloud Migration Center includes a calculator for SAP workloads, which we use alongside our own models where Google Cloud is in scope.
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Deliverables
- On-premise cost baseline with sources and assumptions
- Right-sized cloud cost model for each option
- Licence reuse and compliance summary
- Year-by-year cash flow covering the migration period
- Written business case and executive summary for approval
- Assumptions register your finance team can update
Frequently asked
Will the cloud always be cheaper than on-premise?
Not always. Some steady, fully used workloads cost about the same or more in the cloud, while others save a great deal. A fair business case shows both and also weighs benefits like resilience and avoided hardware refresh.
How accurate is the model?
It is as accurate as the data behind it. We size on measured utilisation, use each provider's own pricing tools and write down every assumption, so your finance team can test and adjust it.
Can you compare more than one cloud?
Yes. We can model AWS, Microsoft Azure and Google Cloud side by side on the same workload set. This is useful when you are deciding between providers or planning a multi-cloud estate.
Do you include SAP licences in the comparison?
We include SAP-related costs as you provide them, such as maintenance, subscription and infrastructure. We do not set SAP prices, but we structure the comparison so RISE with SAP and self-managed options are assessed on the same basis.
Can the business case include funding from the cloud provider?
Yes. Hyperscaler funding programmes can offset part of the assessment or migration cost, subject to eligibility. We help secure funding and show it separately so the case stands on its own without it.
Often paired with this
Plan your move with people who know SAP.
One working session with our cloud and SAP architects. You leave with the options, the risks and a first plan.
- Your landscape reviewed
- The right cloud and region
- A first roadmap
We call our approach to Business Case & TCO the Marwell Lens: advice that stays on your side of the table.
AWS, Microsoft Azure, Google Cloud and SAP are trademarks of their respective owners.