Automation Testing vs Manual Testing: Key Differences

What is the difference between automation testing and manual testing? This blog explains the key usage of both the testing procedures and their pros and cons.


Over the decades, automation testing has been a part of many industries. With test automation, businesses can execute thousands of test cases and save precious time. But at the same time, test automation tends to miss the complexities and nuances of cases which can be better handled by QA (Quality Assurance) testers through manual testing.  Even today, businesses debate over automation testing vs manual testing, and which is better. Let’s take a look at both these testing procedures and understand the differences between the two and the benefits of one over the other.

What is Manual Testing?

Manual testing is a procedure where humans perform tests step by step, without test scripts. Manual testing aims to assure quality, like catching bugs and feature issues before a software application goes live. It is chosen for cases that require focused attention.

Below is a list of tests which can be done manually:

Exploratory Testing – Manual testers check a system without a plan or specific directions to discover bugs and user interface issues. The procedure tries to mimic the personal freedom and choices of the end user.

Usability Testing – QA testers put the website through several user scenarios likely to be encountered while using it. It needs to be performed by users who are different from website developers to get unbiased results.

Ad-hoc Testing – Ad-hoc testing is random testing that does not follow any documentation or process, but only scenarios determined by the tester, to find defects in the application. It is also known as ‘error guessing’ and requires people with the domain expertise to execute it.

When should Manual Testing be used?

Manual testing prevails when human-like skills, such as cognitive and behavioural abilities, are required to test software or applications. The following scenarios where manual testing should be chosen over automated testing:

Flexibility is required: Running manual tests allows more flexibility as it is quicker to set up and the QA testers can immediately see results. However, it requires QA testers who have the agility and a proactive approach. The analyst should have a technical understanding of the test case.

Short-term projects: Automation testing takes longer to set up and requires more planning and investment, so would not be suitable for short-term projects that focus on minor features or has minimal code. It would unnecessarily involve high effort and cost of infrastructure in running tests that have a narrow scope.

End-user usability is being tested: Only manual testing can judge a software or application’s functionality, usability, aesthetics and behaviour. An automation tool cannot decide whether a software interface looks and feels good, or whether it will provide satisfaction to the end user.

How does Manual Testing work?

In the manual testing process, the QA tester validates the application’s key features. The analyst executes test cases and develops summary error reports. Below are the steps to manual testing process:

  • Analyse requirements according to the software requirement specifications document and create a clear test plan.
  • Write test cases that cover all the requirements from the document
  • Get test cases reviewed by the QA lead
  • Execute test cases
  • Detect any bugs and report the bugs
  • Once the bugs are fixed, repeat the failed tests to re-verify the fixes.

What is Automation Testing?

Automation testing is the procedure to execute tests automatically using a test framework and other automated tools or software. Testers set up frameworks and create test scripts that automate user actions to test software or application.

Below is a list of tests that can be automated:

Unit tests – These tests focus on functions or methods of the software to ensure that they are working correctly.

Integration tests – These tests focus on the interaction between different units of code to make sure that they are collectively working correctly.

Functional tests – These tests check the system’s overall functionality from the users’ perspective.

Performance tests – These tests measure the performance of the system, such as response time and output, to make sure that the system can handle the expected load.

Acceptance tests – These tests verify that the system meets the acceptance criteria defined by the customer

Security tests – These tests identify and address security vulnerabilities in the system

Regression tests – These tests identify and address regressions, or unintended changes, that may occur as a result of code changes. JUnit, TestNG, Selenium, Appium and Cucumber are some test automation tools used to run automation testing.

When should automation testing be used?

Following are the common scenarios that require testing automation over manual testing:

  • When a large number of repetitive tests have to be run: If there is a large volume of repetitive tests to be run, automation testing is the best approach. For instance, automation testing can be used to run regression tests from time to time and check whether newly added codes have not disrupted any existing features. This function does not require manual supervision and can be easily done through automation.
  • When human resources are scarce: In case a project is short on QA testers and analysts, it can be best executed within a timeframe through automation testing. Automation also leaves scope for humans to focus on areas that require focused attention, rather than spending time on repetitive tests. Automation testing also helps in deriving better accuracy in parallel testing.

How does automation testing work?

The automation testing process involves testers writing test scripts that have to be executed by automation tools. Test scripts or test frameworks are a set of instructions to be performed on target platforms to validate a software or application feature. These scripts are integrated with various components like:

  • Function libraries
  • Test-data sources
  • Object details
  • Other reusable modules

It is crucial to choose the right automation testing framework to optimise high performance with low maintenance costs.

Manual vs Automation Testing: Key differences

Here is a comparison table of the differences between manual and automation testing based on test parameters:

Test Parameter Manual TestingAutomation Testing
ExecutionExecuted manually by QA testersExecuted automatically by automation tools and software
AccuracyLower accuracy due to higher probability of human errorHigher accuracy due to computerised testing that eliminates possibilities of human errors
ScaleRequires more time and effort when large-scale testing is neededAutomation testing can easily perform large-scale testing
Turnaround TimeTurnaround time is higher as the entire test cycle takes more time to completeTurnaround time is low as the test cycle takes less time to complete
Cost Efficiency

Requires investment in QA testers and analysts to perform testing, and thus is costly.


But, it is more cost-efficient than automation testing in the case of short-term projects

It Is more cost-effective as once the software is integrated, it works for a long time.


But if the project is short-term, then investing in automation may be less cost-efficient than manual testing.

User ExperienceSince it requires human observation and cognitive skills, manual testing ensures a better user experience for the end user.Since automation lacks human observation and cognitive skills, it cannot ensure quality user experience.
Error Identification  Can easily identify bugs and errorsAutomation testing cannot identify bugs and errors that it was not programmed to identify
Areas of specializationManual testing is used to perform Exploratory Testing, Usability Testing and Ad-hoc Testing.Automation Testing is used to perform Regression Testing, Load Testing, Parallel Testing, Performance Testing and Repetitive testing.
User SkillsUsers must be able to mimic user behaviour and build test plans to test all the possible scenariosUsers must be skilled at programming and test scripting to build test cases and automate test as many scenarios as possible
FlexibilityMore flexible as there are no test scripts, but only deep understanding of technical and user behaviourLess flexible as the test automation runs on a pre-determined test script, leaving less scope for change during the test process

Pros and cons of manual testing:


  • Better handles complex scenarios
  • More flexible and agile
  • Ensures better user experience for the end user
  • More cost-efficient in short-term projects
  • Explores features and app behaviours in detail


  • Is slow and tedious
  • Less efficient due to the possibility of human error
  • Involves high investment in QA testers
  • Difficult to ensure sufficient test coverage

Pros and cons of automation testing:


  • Is Cost-efficient
  • Reduces human labour
  • Eliminates human error
  • Can run a large number of algorithm-based tests
  • Simple and repetitive tasks are better handled by test automation
  • Faster turnaround time
  • Provides better accuracy


  • Lacks cognitive ability and human-like decision-making skills
  • Test automation fails when it encounters issues with test scripts or test framework
  • Takes a long time to set-up
  • Less flexibility as the tests run on pre-determined test scripts
  • Not suitable for short-term projects

Manual testing vs automation testing: Which is better

In automation testing vs manual testing, it cannot be said that one testing process is better than the other. While manual testing is slow and tedious, it has the ability to tackle complex cases. On the other hand, though automation cannot tackle cases requiring cognitive abilities, it can test cases with more accuracy and eliminate human error.

In business cases, it is important to strike the right balance between the two. It is important to map which tests can be run manually and which parts require automation tools so that businesses can save both time and money.

Can automation testing replace manual testing?

No, automation testing cannot replace manual testing. The reason is that automation cannot provide the same cognitive skills and human-like intelligence that can be derived from manual testing. Many software and applications used in businesses, such as the ones used for interacting with customers, require a certain level of emotional intelligence and decision-making. This involves testing usability, functionality and behaviour, which only analysts and QA testers can provide.

However, automation testing is constantly evolving. Test automation provides higher accuracy for algorithm-based test cases than manual testing. Many factors are influencing the landscape of test automation, such as the requirement to modify test tools to fix shortcomings, generating almost total test coverage and the requirement for proper test management procedures.

Going forward, those businesses will succeed that have a proper strategy in place to utilise both manual and automation testing to deliver a product with optimum quality. The future lies in manual automation where manual testing and automation testing will go hand in hand. Even though automation testing tools can build test cases and codes, the output of these tools will still have to be verified by QA testers. This makes the future of manual automation a bright one.


Hence, no one factor can determine which of the two testing processes, that is, automation testing vs manual testing is the best. It depends from case to case that which testing procedure is best suited. Constant advances in automation tools and software, and the need to test them manually for configuration and operational issues, hold a bright future for manual automation.


  1. What cannot be automated in testing?

Tests based on testing user experience, i.e., they require responses only from a human/user to test how easy and comprehensive the app is to use, can be done only through manual testing. Also, tests that require Ad Hoc or Random Testing based on domain knowledge or subject matter expertise cannot be automated.

  1. What are the limits of testing automation?

Some limitations of testing automation are as follows:

  • Cannot handle complex tasks
  • Test automation fails when it encounters issues with test scripts or test framework
  • Frequent updating of the test frameworks is required with every update in user feedback
  • Automation is expensive in the case of small-scale projects
  • Automation testing cannot identify bugs and errors that it was not programmed to find.
  • Lack of cognitive ability to understand the users’ perspective
  1. What is the latest trend in automation testing?

The latest trend in test automation is the rise in Artificial Intelligence (AI) and Machine Learning (MI). These trends are expanding their footprint in all directions, from chatbots to websites to mobile applications, and will continue to do so in near future. The automation tools Cypress, Playwright and Jest will be the trendsetter in 2023. Though usage of Selenium-framework will continue, organisations may look for AI-based alternatives to perform automation testing.