For now, we will look at the points of difference between these two. This would give you a fair bit of idea, regarding both these.
It is carried out manually where a tester himself executes all the steps e.g. in a test case.
Manual testing is the most basic step. Without carrying out manual testing, one cannot proceed towards automation testing.
In this kind of testing, testers carry out random testing in order to discover bugs.
Due to error guessing technique followed in manual testing, we get more bugs in general than that of automation testing.
Time consumed is more in this case.
Manual testing is generally carried out in a sequential manner.
Carrying out regression testing is tedious in manual testing.
More testers are required in Manual Testing on the grounds that in this test cases should be executed manually.
The results are with lesser accuracy as manual errors come into picture.
Batch testing cannot be performed over here.
The reliability of manual testing is considered to be less.
Programming is not involved in manual testing.
Manual testing is considered to be of lower quality.
Manual testing can be carried out without the use of any tool.
All the well known stages of STLC like test planning, test deployment, result investigation, test execution, bug tracking and reporting tools clearly come under the class of Manual Testing and done effectively by human endeavors.
It is carried out with the help of various automation tools like QTP, Selenium etc. There are many available in the market. Based on factors like requirement and budget, one needs to chose one.
Automation testing can be said to be an integral and continuous part of manual testing.
In case of automation testing, we do the testing of the application via running the scripts. Tools allow us to write scripts and execute them as well.
Automation testing is more useful when repetitive functionalities of the software are to be tested.
Time consumed is less as expected.
Automation testing is carried out on a number of machines at one time.
Regression testing is easier to carry out during automation testing due to the use of tools.
Fewer testers are required in Automation Testing on the grounds that in this test cases should be executed by utilizing Automation Tools.
Results are highly accurate as manual errors are out of question over here.
Multiple kinds of batch testing can be carried out in case of automation testing.
Automation testing is considered to be more reliable amongst the two as there is involvement of tools in the same.
Programming is the heart of automation testing as scripts need to be written in various languages like Perl, python etc.
Automation testing is considered to be of higher quality.
Tools form an integral part of automation testing.
In Automation Testing all the popular stages of STLC are finished by different open sources and paid tools like Selenium, J meter, QTP, Load Runner, Win Runner etc.