Improve Your Project’s Future Prospects with Capacity Testing

The industry statistics say that 40% of users abandon a site if it takes more than 3 seconds to load. And when it comes to eCommerce websites, even a delay of one second can cost businesses more than $250,000 annually. Additionally, 79% of users never return to a website when the website’s performance is slow.

Capacity Testing Boosts Profits Through Faster Response Times

With the increase of internet users, amount of data, and speed it moves, the question arises. – Is your application ready to meet the rising expectations, capable of taking that load, bearing the weight of traffic, and handling the myriad of calls and requests made by the users using your application?

You will get all your answers with – Capacity Testing.

What is Capacity Testing?

Capacity testing is a type of testing carried out to determine how many users an application can smoothly handle while still delivering a flawless user experience. It ensures the application can run the maximum number of users as per the performance requirements.

Although your system’s Service Level Agreement (SLA) dictates the current number of users, planning for future capacity is vital. The role of capacity testing is to plan for future growth the system could receive. For instance, you need to understand what new resources are required when your system hits future resource utilization levels.

Additionally, it can be used in the design phase to quickly benchmark the quantity of users the system can handle under the given circumstances. It also plays a crucial role in effective strategic planning as you can proactively increase the infrastructure before reaching limits. Thus, you avoid negatively affecting the user experience.

Some development teams confuse Capacity Testing, Load Testing, and Stress Testing with one another. They are all essential and yet distinct parts of performance testing the system.

What is Load Testing?

Load Testing involves putting the application code and environment under different load scenarios to understand better what the system can handle. For example, Load Testing discovers how the application system reacts to fluctuating numbers of users by monitoring the response time of the page.

What is Stress Testing?

The goal of Stress Testing is to push the system past its planned capacity to try to break the system. Watching the system’s behavior when subjecting the application to intense conditions is essential. Stress testing is typically performed before deployment to the production environment to identify server misconfigurations and vulnerabilities.

As we have already given you a sense of the different performance tests and why capacity tests are critical tests involved in performance testing, it’s time to take a walkthrough with some of the key benefits it has in store for us.

Benefits of Capacity Testing

Effective Capacity Planning

There’s no doubt that capacity testing significantly helps in planning and designing the infrastructure, which leads to optimizing the overall quality of the software. The accurate traffic estimates from capacity testing are crucial inputs to the planning process. They help you achieve optimal performance results per your SLAs. Thus, improved planning plays a significant role in understanding the maximum number of users or transactions the software can withstand per system or infrastructure configuration.

Enhanced Peak Time Performance

Capacity testing can help organizations better prepare for sudden surges in business volume when properly planned and executed. Thus, this type of testing is best suited for conditions where an unexpected spike in demand would cause many issues for end-users.

Two instances where this testing is crucial are 1) the rise in the number of visitors to a cricket website during world cup matches and 2) the increase in the load on medical insurance companies after a natural disaster or a global pandemic, like COVID-19.

Optimized Usage of Time & Resources

The data extracted from capacity utilization can help you prepare in advance for unexpected peak times. Additionally, it can help when your organization is on a fast growth track. As a result, it gives you a clear picture regarding the amount of load the system can handle successfully at the allocated memory, hardware, and network resources.

Once you have a better idea of the capacity the system can hold, you can spend your capital wisely on additional resources.

Realistic Performance SLAs

Capacity testing offers actionable insights to decision-makers on how to use their infrastructure efficiently. It encourages them to create performance SLAs and set non-functional requirements that are more realistic and in sync with the changes and events in the future. Also, it helps in creating and managing benchmarks that can be shared with all the relevant stakeholders and decision-makers seamlessly. Sharing benchmarks results in high productivity and reduced cross-department differences or friction.


In addition to the key benefits listed above, capacity testing can help uncover hidden issues, loopholes, or vulnerabilities in your ecosystem. All of these issues can cost you dearly in terms of both capital and time. Capacity testing helps find and fix the most critical flaws or priority issues, thus avoiding infrastructure or performance issues.

Best Practices for Capacity Testing You Should Consider

Setting Relevant and Realistic SLAs

It is crucial to set proper criteria and SLAs. In most cases, the automation tool you use before deploying the software to the production environment may lack understanding regarding the business processes associated with the software.

To avoid these pitfalls, an automation engineer should remain in touch with the product owners, business analysts, and subject matter experts. Staying in touch ensures the SLAs are relevant, realistic, and accurate to the most crucial use cases.

Sticking to the 80/20 Rule

Experts recommend sticking to the 80/20 rules for all the aspects of performance testing, including performance, volume, load, among others. By applying the 80/20 rule, you can ensure your focus is on the more critical and volatile processes. These processes are most likely to impact your company’s profit significantly or might create unwanted bottlenecks.

Documenting the detailed test specification

Documenting the details of the test specifications is recommended before conducting the capacity test. The document should include different parameters such as hardware specification, type of network, data volumes, software version & client type, number of processes running in the background, etc. The more detailed your documentation report would be, the closer you are to addressing or mitigating potential issues.

Automating Capacity Testing

Experts recommend running the capacity tests continuously with varied data sets. This allows you to fine-tune the application with the infrastructure to find various hidden issues. Reducing manual interference helps in identifying some intermittent bugs after a few test runs. Hence automating the process would yield better results.

While selecting your automation tool, make sure to pick the one that can help you monitor both black box and white box results to identify the root cause of a particular problem quickly.

Result Comparison & Reporting

More often than not, you would find friction and lack of communication between different functional teams, which can easily be prevented with capacity testing. You can create comprehensive reports and share detailed insights with the key stakeholders. This not only improves transparency across different cross-functional teams but also fosters collaboration between different departments.

You should perform capacity testing across different infrastructure configurations. For instance, it makes sense to run capacity tests with different conditions and geographical locations.

What to Include in a Capacity Test Result Report

When it comes to what to include in your capacity test result report, it is advisable to include all the critical metrics generated from the testing. These metrics should focus on different end-user loads applied until the application stops meeting the SLA. The most crucial part is the load test result immediately before the SLA starts failing.

  • Transaction execution %
  • Transaction failure rate
  • Error percentage
  • Throughput
  • Response time numbers (Minimum, Maximum and Average)
  • Server utilization at different load levels and variance in the numbers

Including the results of at least 3 to 4 rounds of tests can provide the most accurate Capacity value.

Capacity Testing Bottom Line

In a nutshell, improving your capacity testing and capacity planning can help determine the proper infrastructure required for each given scenario. Following this provides a flawless user experience by enhancing the overall quality of your application and keeps your customers happy. It is an ideal way to identify and set your scaling strategy to determine whether you should scale up or not.

Bottom Line Increases the Bottom Line

So go ahead, embrace capacity testing and avoid potential problems pertaining to your application in the future.