AWS Migration Cost Calculator - What Cloud Migration Actually Costs in 2026

If you’re looking for the full migration process (strategies, tools, step-by-step phases), see our complete AWS cloud migration guide. This post focuses purely on costs.

AWS migration cost breakdown: the two buckets

Every migration has two distinct cost categories that people often conflate:

1. One-time project costs: the investment to actually move your workloads to AWS (consulting, engineering, tooling, testing)
2. Ongoing infrastructure costs: what you pay AWS monthly after migration is complete

Most “cloud migration cost” articles only discuss one or the other. You need to model both before making a go/no-go decision.

One-time migration project costs

These are the costs of the migration itself: assessment, architecture design, infrastructure as code development, data migration, testing, cutover, and stabilisation.

By company size

What’s included in the project cost

Project costs are shown in EUR (our billing currency) with USD equivalents. AWS infrastructure costs below are in USD as that’s how AWS bills globally.

• Assessment phase (3-10 days): infrastructure audit, dependency mapping, TCO model, strategy recommendation per workload
• Architecture & IaC (2-6 weeks): target architecture design, Terraform/Terragrunt module development, CI/CD pipeline configuration, multi-environment setup
• Migration execution (2-12+ weeks): server migration (MGN), database migration (DMS), application containerisation, DNS cutover
• Post-migration stabilisation (2-4 weeks): performance tuning, cost right-sizing, monitoring/alerting setup, knowledge transfer

Factors that increase project cost

Factors that decrease project cost

Ongoing AWS infrastructure costs (monthly)

After migration, your monthly AWS bill replaces your previous hosting costs. Here’s what to expect based on real environments:

Small application (startup, single product)

Typical profile: 1 web app, 1 API, 1 database, low-moderate traffic (under 100K requests/day)

Compare this to Heroku: 2 Standard-2X dynos + Heroku Postgres Standard-0 = ~$300-400/month for equivalent capability.

Mid-size platform (growing SaaS, 5-15 services)

Typical profile: microservices architecture, multi-AZ, CI/CD, monitoring stack, moderate traffic

Enterprise (regulated, multi-service, high availability)

Typical profile: 20+ services, multi-AZ, encryption everywhere, compliance monitoring, high traffic

Hidden costs that catch teams after migration

These are the costs nobody warns you about in the vendor pitch deck:

1. Data transfer (egress)

AWS charges $0.09/GB for data leaving AWS to the internet. Teams that didn’t model egress during planning see bills 2-3x higher than expected. This is especially painful when:

• Your application serves large files (images, videos, documents)
• APIs respond to many external clients
• You have integrations with systems still on-premise

Mitigation: Use CloudFront for cacheable content (reduces egress costs by 40-60%), VPC endpoints for AWS service traffic, and PrivateLink for VPC-to-VPC.

2. Cross-AZ data transfer

$0.01/GB in each direction between availability zones. Sounds tiny, but a chatty microservices architecture doing 100M cross-AZ requests/month at 5KB average = ~$10/day = $300/month just in inter-service data transfer.

Mitigation: Co-locate tightly-coupled services in the same AZ where possible. Use AZ-affinity for service mesh routing.

3. NAT Gateway processing charges

$0.045/hour (~$33/month) + $0.045/GB of processed data. Every outbound internet request from private subnets goes through NAT. At 500 GB/month processed data = $22 in data charges on top of the hourly fee.

Mitigation: Use VPC endpoints for S3, DynamoDB, and other AWS services (eliminates NAT for that traffic). Consider NAT instances for dev/staging environments.

4. CloudWatch Logs ingestion

$0.50/GB ingested. Verbose application logging at 1 GB/day = $15/month. Multiply by 10 services = $150/month just for log storage. And that’s before you add log retention.

Mitigation: Set appropriate log levels per environment (ERROR in prod, DEBUG only in dev). Use log sampling for high-volume endpoints. Set retention policies (30 days for most logs).

5. Idle non-production environments

Dev and staging environments running 24/7 when developers only use them during business hours = paying for 128 hours/week of idle time out of 168 total.

Mitigation: Schedule non-production environments to shut down outside business hours. This single change saves 60-65% on dev/staging costs. Use Lambda-based schedulers or AWS Instance Scheduler.

On-premise vs AWS: total cost of ownership comparison

The real question isn’t “how much does AWS cost?” but rather “how does AWS compare to what I’m paying now?”

On-premise TCO (often underestimated)

The break-even calculation

For a typical 5-server on-premise setup (2 app servers, 1 DB, 1 staging, 1 DR):

• On-premise TCO: $4,500-13,750/month
• Equivalent AWS (mid-size platform): $900-1,700/month
• Migration project cost: €46,000–€110,000 ($50,000-120,000) one-time
• Break-even point: 4-12 months after migration

After break-even, you’re saving $3,000-12,000/month on a permanent basis. Plus you get automatic scaling, managed security, and no hardware refresh cycles.

How to reduce migration costs with AWS funding

As an AWS Advanced Tier Partner, we help clients access migration funding that significantly reduces out-of-pocket costs:

AWS Migration Acceleration Program (MAP)

• What it covers: Up to 70-80% of partner engagement costs (assessment, migration execution, modernisation)
• Who qualifies: Companies migrating from on-premise or competing cloud providers with annual AWS spend commitment
• Typical benefit: A €92,000 ($100K) migration project → you pay €18,000–€28,000 ($20-30K) out of pocket
• Timeline: Funding approval takes 2-4 weeks; can be applied retroactively in some cases

AWS Proof of Concept (PoC) Programme

• What it covers: The prototyping/validation phase of migration, including architecture design, PoC build, and performance testing
• Who qualifies: Companies evaluating AWS for new workloads or migration
• Typical benefit: €4,500–€14,000 ($5,000-15,000) in funded PoC work

AWS Credits for Startups

• What it covers: AWS infrastructure credits (applied to your monthly bill)
• Who qualifies: Startups in accelerator programmes, VC-backed companies
• Typical benefit: $10,000-100,000 in AWS credits over 1-2 years (applied to infrastructure bill, billed in USD)

Cost reduction strategies post-migration

Once you’re on AWS, these are the levers for ongoing cost reduction:

For a detailed guide on Savings Plans vs Reserved Instances, see our AWS Savings Plans guide.

Cost comparison: Heroku vs AWS vs on-premise

Here are the most common migration paths we see, and how costs compare for a typical web application (API + database + worker + Redis):

Note: Heroku costs escalate rapidly with scale. The prices above assume moderate traffic. At 10x traffic, Heroku costs can 3-5x while AWS costs increase 30-50% due to auto-scaling efficiency.

When migration is NOT worth the cost

Migration doesn’t always make financial sense. Don’t migrate if:

• Your application is end-of-life (retiring within 12 months). The ROI window is too short.
• You’re a 2-3 person team with no compliance requirements. PaaS simplicity has real value for small teams.
• Your current hosting costs are under $200/month. The migration investment won’t pay back.
• You have no traffic growth. If nothing is changing, there’s no trigger for the investment.

Migration makes sense when at least one of these is true:

• Monthly hosting exceeds $1,000 and growing
• Compliance deadlines are approaching (SOC 2, ISO 27001)
• You need multi-region, auto-scaling, or network isolation
• Your team needs full infrastructure control and ownership

Frequently asked questions

Get a cost estimate for your migration

Every migration is different. The numbers above give you ranges, but a proper estimate requires understanding your specific environment: number of applications, database engines, traffic patterns, compliance requirements, and current costs.

Want a cost estimate for your migration?

Book a free 30-minute call. We'll map your current environment and give you a rough TCO comparison within a week.

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