Google’s default Quality Score is 5. The score is scaled from 1 to 10. Where your Quality Score ranks (higher or lower than 5) will illustrate how you compare with your competitors in your industry.
If you are seeing poor results, with a low click-through rate then it is possible your Quality Score can fall as low as a 1 on the scale. A Quality Score of 1 will inflate your CPC by 400% compared to a standard score of 5.
On the flip side, if your ads are crushing it and users are constantly clicking it then your score can reach a perfect 10. A score of 10 will reduce your CPC by 50% compared to an average score.
In summation, a “good” Quality Score will be anything over a 5.