How often can I take the Duolingo English Test?

According to the information in the official exam guide, you can purchase up to 3 Duolingo English Tests within any 30-day period. This means you can take the test a maximum of three times within a month. However, if you have already received a certified test result and still wish to retake the test, you will need to check if the system allows you to continue purchasing additional tests. It is important to note that the validity of the test results is two years, and certified test results can only be sent out from your registered account.