How much does it cost to migrate to AWS?
Migrating to AWS typically costs between $50,000 and $250,000 for a small or mid-sized workload estate, while large enterprises with hundreds of servers and tightly-coupled applications routinely spend $1M or more across the full programme. The number swings this widely because "migration cost" is not one line item — it is the sum of assessment, engineering labour, data transfer, a parallel-running period where you pay for both environments, staff retraining, and contingency.
A useful anchor: a typical mid-market move — roughly 100 servers, 20 TB of data, delivered over 9–12 months — tends to land in the $1.5M–$3M range once every cost is counted, not just the AWS bill. If a quote you receive is far below that for a comparable estate, it is almost certainly ignoring the double-run window or the refactoring backlog. This guide breaks the number down so you can build a defensible migration budget instead of a hopeful one.
What drives the cost of an AWS migration?
Five variables move the total more than anything else. Get an estimate on each of these and you have 80% of your budget:
- Workload count and complexity. Cost scales with the number of applications and how entangled they are. Ten stateless web services are cheap; one 15-year-old monolith with undocumented dependencies is not.
- Migration strategy (the "R" you pick per app). Rehosting is the cheapest per workload; re-architecting can cost an order of magnitude more. Most estates use a mix.
- Data volume and egress. Moving terabytes out of an existing data centre or another cloud incurs transfer time and, when leaving another provider, egress fees. Large datasets may justify a physical transfer appliance.
- Parallel-running window. During cutover you pay for on-premise and AWS simultaneously. The longer the overlap, the higher the cost — this is the single most underestimated line item.
- Partner and engineering rates. Whether you use internal staff, a global consultancy, or a specialist team changes the labour cost per workload dramatically.
Notably, the AWS compute-and-storage bill is often the smallest of these. Teams that fixate on instance pricing while ignoring the double-run window and integration work consistently blow their budgets.
How much does AWS migration cost by strategy (the 7 Rs)?
AWS frames migration around seven approaches — rehost, relocate, replatform, refactor, repurchase, retire, and retain. The three that carry real engineering cost are below. Figures are indicative per application group, not per server, and assume external delivery.
| Strategy | What it means | Typical cost | Best when |
|---|---|---|---|
| Rehost (lift & shift) | Move the workload as-is onto EC2 with minimal change | $40k–$150k | You need speed, or to exit a data centre lease fast |
| Replatform (lift & reshape) | Swap in managed services — RDS, ElastiCache, managed Kubernetes — without rewriting the app | $100k–$250k | You want lower ops burden without a full rebuild |
| Refactor (re-architect) | Redesign into microservices, serverless, or event-driven patterns | $200k–$600k+ | The app is strategic and current architecture blocks growth |
A word of caution on rehosting: it is cheapest to execute but a naive lift-and-shift can raise your steady-state cloud bill by 20–30% versus on-premise, because you carry oversized VMs into an environment that charges by the hour. Rehost to move fast, then right-size and replatform the workloads that matter. Deciding which apps deserve which "R" is where a structured cloud migration checklist earns its keep.
What are the hidden costs people forget to budget for?
The sticker price of the migration project rarely matches the cash that actually leaves the business. Budget explicitly for these:
- Assessment and discovery: $10k–$150k depending on estate size — dependency mapping, business cases, and a target architecture.
- Parallel running: weeks to months of paying for two environments at once. Compress this window aggressively; it is pure duplicated spend.
- Data transfer and transformation: $10k–$200k for large migrations, including egress from an incumbent cloud and any schema conversion.
- Licensing changes: Windows, SQL Server, or Oracle licences often need re-negotiating; bring-your-own-licence rules differ on cloud.
- Retraining and hiring: your team needs AWS fluency. Upskilling is a real line item, and so is the cost of not having the skills mid-project.
- Contingency: 15–20% on top. Something will be more entangled than the discovery suggested.
How much will AWS cost each month after migration?
Migration is a project cost; the AWS bill is a run-rate cost, and the two should be modelled separately. A general-purpose 2 vCPU / 8 GB instance runs roughly $30 per month on-demand — trivial alone, but multiply across an estate and add storage, data transfer, load balancers, and managed databases, and it compounds.
The good news is that run-rate is where cloud earns its return. A well-executed migration commonly cuts compute and storage cost by up to 66% versus on-premise, and moving x86 on-demand workloads to Graviton (Arm) instances on Savings Plans can reduce equivalent compute cost by 50–65%. Right-sizing, auto-scaling, and reserved commitments are what turn a migration from a cost event into a savings programme. Designing for that from day one is exactly what the AWS Well-Architected Framework is for. If you are still choosing a provider, our AWS vs Azure vs Google Cloud comparison weighs the run-rate differences in detail.
How do AWS MAP credits reduce migration cost?
Most teams overpay because they never claim what AWS already offers. The Migration Acceleration Program (MAP) provides funding — as AWS credits — typically worth 15–25% of your first-year run-rate spend, released across assess, mobilise, and migrate phases. Two things matter: the credits are earned against milestones and consumption, not handed over upfront; and workloads must carry the map-migrated resource tag before completion, because credits are never applied retroactively. A migration partner who plans for MAP from the assessment stage can meaningfully lower your net cost. One who bolts it on afterward leaves money on the table.
How do you build an AWS migration budget you can defend?
Estimate bottom-up, in this order:
- Inventory every workload and tag it with an "R" (rehost, replatform, refactor, retire, retain).
- Cost each group using the ranges above, weighted by complexity.
- Add the wrapper costs — assessment, parallel running, data transfer, licensing, retraining.
- Subtract MAP credits and any right-sizing savings you can bank in year one.
- Add 15–20% contingency and a target payback date — refactor-heavy programmes commonly pay back in 18–24 months.
This is also where a phased sequence pays off: a right-sized, well-scoped move beats a big-bang cutover on both cost and risk, a theme we cover in depth in our guide to on-premise to AWS migration strategy.
How ILMTEC helps
ILMTEC runs AWS migrations in fixed six-week cycles, which is deliberate: a bounded scope keeps the parallel-running window short and makes cost predictable instead of open-ended. Our AWS cloud migration service starts with a free migration cost assessment — a workload inventory, an R-strategy per application, a MAP-eligibility check, and a run-rate projection — so you walk into the decision with a real number, not a range. From Pune, Dubai, and Berlin, our engineers handle the discovery, the cutover, and the post-migration right-sizing that turns the AWS bill into a genuine saving. If you want a defensible figure for your estate, that assessment is the fastest way to get one.
