How many reviews do you need to reach a 4.5 rating?
The simple arithmetic behind product ratings and how to work out how many 5 star reviews you need.
The formula
Average rating is total stars divided by total reviews. To reach a target T from a current total of S stars over N reviews, you need at least (T x N - S) / (5 - T) new 5 star reviews.
Example
With 100 reviews averaging 4.2, you have 420 stars. To reach 4.5 you need (450 - 420) / 0.5 = 60 more 5 star reviews.
Use the calculator
Type your own counts for each star level and set your target. The calculator does the sums and rounds up to whole reviews.