AWS Cloud Practitioner Study Notes · Part 36
AWS TCO and Cost Tools: Pricing Calculator and Migration Evaluator
AWS Cloud Practitioner study notes explaining Total Cost of Ownership, CapEx and OpEx, AWS Pricing Calculator, and Migration Evaluator.
Total Cost of Ownership (TCO) is the full cost of owning and operating technology over its lifecycle. The purchase price of a server is only one line in the calculation. Power, cooling, networking, software licences, maintenance, staffing, facilities, downtime, and replacement costs can be equally important.
This is Part 36 of the AWS Cloud Practitioner Study Notes. Part 9 introduced AWS pricing, budgets, and billing concepts, while Part 30 showed how purpose-built managed services can affect operational effort.
What is TCO?
A useful model is:
Total Cost of Ownership
= acquisition costs
+ infrastructure operations
+ software and licences
+ people and support
+ downtime and riskFor an on-premises data centre, costs may include:
- Servers, storage, and networking equipment
- Racks, UPS systems, and physical facilities
- Electricity and cooling
- Internet and private connectivity
- Hardware warranties and maintenance contracts
- Software licences
- System, network, security, and database staff
- Hardware replacement and refresh cycles
- Cost of outages and recovery
If a company buys a server for RM50,000 but spends another RM200,000 on staff and RM96,000 on power, maintenance, and facilities over five years, the TCO is not RM50,000. The decision must compare the complete lifecycle cost with the complete cost of the proposed AWS architecture.
CapEx and OpEx
On-premises infrastructure often involves significant capital expenditure (CapEx). The organisation buys equipment and records the investment over time.
AWS generally shifts much of the spending toward operational expenditure (OpEx). The organisation pays for cloud resources and services as they are used, although commitments such as Savings Plans or Reserved Instances introduce longer-term purchasing decisions.
| On-premises | AWS cloud |
|---|---|
| Buy servers before demand is known | Provision capacity when needed |
| Build and operate data-centre facilities | Use AWS data-centre infrastructure |
| Pay for owned capacity even when idle | Scale capacity based on demand |
| Replace failed hardware | AWS manages the underlying hardware layer |
| Large upfront investment | Usage-based service charges and possible commitments |
The accounting classification is not the entire business case. AWS still has costs for compute, storage, data transfer, support, operations, security, migration, and application changes. A cloud design should be measured with realistic usage and architecture inputs rather than assuming that “pay as you go” automatically means cheaper.
How AWS can reduce TCO
AWS may reduce total cost when the workload benefits from elastic capacity, managed services, or higher utilisation. Common mechanisms include:
No data-centre hardware purchase
The company does not need to purchase servers, racks, cooling systems, or replacement disks for the AWS infrastructure it consumes.
Elastic capacity
An on-premises team may buy enough servers for the peak even if average utilisation is low. An AWS Auto Scaling group can add EC2 instances for a demand spike and remove them when demand falls, within the application’s design limits.
Managed services
Services such as Amazon RDS, Amazon S3, and AWS Lambda can reduce routine infrastructure administration. For example, RDS handles many provisioning, patching, backup, and infrastructure tasks that a team would otherwise manage on EC2.
Better resource utilisation
Rightsizing, automatic scale-in, serverless capacity, and consumption-based storage can reduce payment for idle resources. These benefits require monitoring and governance; unused EBS volumes, unattached Elastic IP addresses, over-sized instances, and unnecessary data transfer can still increase AWS costs.
Faster provisioning
Infrastructure as Code and managed services can reduce the time needed to launch or change environments. Faster delivery is a business value in addition to direct infrastructure savings.
A TCO calculation workflow
Use a structured process:
1. Define the workload and comparison period
2. Inventory the current environment
3. List direct and indirect costs
4. Measure actual utilisation and demand patterns
5. Design the equivalent AWS architecture
6. Estimate AWS service and operational costs
7. Include migration, support, data transfer, and licensing
8. Compare TCO, risk, resilience, and business agilityThe comparison period might be three or five years. Use the same workload scope and service-level expectations on both sides. Comparing one physical server with only one EC2 instance is not meaningful if the AWS target also includes a load balancer, Multi-AZ database, monitoring, backups, NAT Gateway, support plan, and security services.
AWS Pricing Calculator
AWS Pricing Calculator is a free web-based planning tool for estimating AWS service costs. You can model a new architecture or changes to an existing workload by selecting services, Regions, resource specifications, usage, and payment options.
Choose services
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Configure Region and usage
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Review service calculations
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Estimate monthly and upfront costsFor an application, you might estimate:
- EC2 instances or Lambda requests
- EBS volumes and snapshots
- RDS or Aurora capacity
- S3 storage and requests
- Elastic Load Balancing
- Data transfer
- CloudWatch and other observability services
- Support plans or commitment options where applicable
When to use the Pricing Calculator
Use it when the question is about the expected cost of an AWS design:
- “How much will this workload cost per month?”
- “What is the cost of two EC2 instances and an RDS database?”
- “How much would moving this architecture to another Region cost?”
- “What is the impact of changing the instance size or payment option?”
The calculator is an estimate, not a guaranteed invoice. Accuracy depends on the inputs, including Region, hours, requests, storage, data transfer, and scaling behaviour. Actual prices and usage can change, and estimates may not include every tax, third-party licence, support implication, or unlisted service.
Exam shortcut: estimate the AWS cost of a planned workload → AWS Pricing Calculator.
AWS Migration Evaluator
AWS Migration Evaluator, formerly known as TSO Logic, helps organisations build a business case for moving existing on-premises workloads to AWS. It is designed for comparison rather than merely pricing a new AWS architecture.
It can use inventory and utilisation information such as:
- Server CPU and memory usage
- Storage capacity and I/O
- Existing virtual machines and physical servers
- Software licensing considerations
- Utilisation patterns and workload characteristics
Current data centre
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Inventory and utilisation data
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Migration Evaluator assessment
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AWS migration scenarios and projected savingsThe result can help stakeholders compare migration patterns, estimate the AWS cost of running the workloads, and evaluate potential savings. It is especially useful when the organisation does not yet know the appropriate AWS instance sizes or wants evidence based on current infrastructure utilisation.
Exam shortcut: compare existing on-premises costs with AWS and estimate migration savings → AWS Migration Evaluator.
Pricing Calculator versus Migration Evaluator
| Tool | Main question | Typical starting point |
|---|---|---|
| AWS Pricing Calculator | What might this AWS workload cost? | Proposed AWS services and usage assumptions |
| AWS Migration Evaluator | What might it cost to move this existing environment to AWS? | On-premises inventory and utilisation data |
The tools can complement each other. Migration Evaluator can help build the migration business case, while Pricing Calculator can model a specific target architecture, service change, Region, or commitment scenario.
Example: migrating 20 servers
Suppose a company operates 20 physical and virtual servers in a data centre. Management asks whether moving to AWS would reduce cost.
Step 1: inventory the current environment
Record the server types, CPU and memory use, storage, network traffic, software licences, maintenance costs, staffing, facilities, and peak patterns.
Step 2: build the migration business case
Use Migration Evaluator to analyse the current environment and model migration scenarios. The assessment can help identify candidate EC2 sizes and possible savings based on actual utilisation rather than the maximum specification of each server.
Step 3: design the target architecture
Decide whether the target needs EC2, RDS, S3, load balancing, Auto Scaling, backups, monitoring, security services, and hybrid connectivity.
Step 4: estimate AWS usage
Use Pricing Calculator to configure the target Region, instance counts, storage, transfer, database capacity, and expected usage. Include scale-out and scale-in behaviour rather than estimating only an idle baseline.
Step 5: compare complete value
Compare the on-premises and AWS TCO, including migration effort, operational staffing, resilience, recovery, compliance, performance, and business agility. A lower infrastructure bill alone may not justify a migration if application changes or data-transfer requirements are large.
Managed services and operational TCO
Operational effort is part of TCO. A self-managed database on EC2 may have a lower visible service price but require more patching, backup, monitoring, failover, and specialist time. Amazon RDS may have a higher direct service charge while reducing routine administration.
This is why a fair comparison includes both:
AWS bill
+ migration and application work
+ operations and support
+ networking and data transfer
+ licensing
+ risk and resilience requirements
= AWS TCOManaged services do not eliminate all engineering work. Teams still own application performance, access control, architecture, data classification, cost governance, and operational decisions.
Common exam questions
| Scenario | Likely answer |
|---|---|
| Estimate monthly AWS costs before deployment | AWS Pricing Calculator |
| Compare an existing data centre with AWS | AWS Migration Evaluator |
| Calculate hardware, power, cooling, and labour together | Total Cost of Ownership |
| Reduce upfront hardware purchases | Pay-as-you-go cloud pricing |
| Reduce routine database administration | Managed service such as Amazon RDS |
| Pay only for capacity needed during a temporary spike | Elastic scaling and consumption-based services |
| Estimate a proposed EC2, RDS, and S3 architecture | AWS Pricing Calculator |
Common exam traps
Server purchase price versus TCO
TCO includes acquisition, operations, people, software, facilities, maintenance, risk, and downtime—not only the server invoice.
Pricing Calculator versus Migration Evaluator
Pricing Calculator estimates AWS service usage. Migration Evaluator compares an existing environment with AWS as part of a migration business case.
Pay-as-you-go versus free
Pay-as-you-go means the organisation pays for usage. It does not mean that the services are free or that every AWS workload costs less than on-premises infrastructure.
Cloud savings versus automatic savings
AWS can reduce hardware and operational overhead, but poor rightsizing, idle resources, data-transfer costs, duplicated environments, and weak governance can increase the bill. TCO analysis must use realistic usage data.
Memory map for CLF-C02
- TCO → complete lifecycle cost
- AWS Pricing Calculator → estimate planned AWS usage
- Migration Evaluator → compare existing on-premises workloads with AWS
- Pay-as-you-go → avoid large upfront hardware purchase
- Elastic scaling → align capacity with demand
- Managed services → reduce routine operational effort
The one-sentence rule is: TCO measures the whole cost, Pricing Calculator estimates AWS, and Migration Evaluator builds the on-premises-to-AWS comparison.
Conclusion
TCO is a broader decision framework than a monthly cloud bill. It includes equipment, facilities, electricity, software, people, maintenance, downtime, migration, and operational effort. AWS may improve the cost and value profile through pay-as-you-go pricing, elastic capacity, managed services, and better utilisation, but the result depends on the workload and the quality of the assumptions.
Use AWS Pricing Calculator for a planned AWS architecture. Use AWS Migration Evaluator when analysing an existing data centre and building a migration business case. Then compare the complete TCO alongside resilience, agility, security, and operational requirements.