You can find many sites which offer free eye test. You just enter their web sites and follow their instructions to test your eyes. Here is a link: https://www.eyeexamonline.com/exam-right-eye_what-letters-are-clear.html
You can take an eye exam at https://www.eyeexamonline.com. Open this site, you will see there is a button named free eye test. Follow the page step by step. After you finish all the steps, you will find the result.
Taking an eye exam online won't offer you the accurate prescription. I would recommend you to go to your eye doctor and have an eye exam there. The doctor can give you a complete exam to detect any eye problems you might get.
There are numerous online eye exams. Some online eye exams are just games and are not a reliable way to test a person's vision; however, there are some online eye exam sites that offer a good first assessment of a person's vision. There are two different types of online eye exams, a focal vision exam and a color blindness exam. Online eye exam cost is usually free. An online eye exam can be a helpful tool for judging if you need an eye exam; however, it is not a substitute for going to an optometrist.