How the overall score is worked out
Your overall score is the average of your five ratings; a tool’s rating is the average of its reviews.
Your review’s score
The average of the five criteria you rated, to one decimal place. You do not set it yourself — it follows from the five stars you gave.
A tool’s rating
The average across all its published reviews, recalculated daily. It appears on the tool page, in comparisons, and in the “Highest rated” sort on category pages.
A tool with no reviews shows no rating rather than a zero — no data is not the same as a bad score.
Reviews and the Popularity Score
Ratings are one of six inputs to the Popularity Score, weighted by how many reviews there are, so a single five-star review does not carry the same weight as fifty. See How the Popularity Score works.