How this calculator works
The mean weights each star value by its review count. A target calculation assumes every new review is five stars and that existing reviews stay in place. It solves the target inequality and rounds the required count upward to a whole review. It uses the exact average rather than a platform rounding or display rule. An average of exactly five is unreachable in a finite number of added reviews if any existing review is below five.
Formula
Average = (n1 + 2n2 + 3n3 + 4n4 + 5n5)/N. Extra five-star reviews = max(0, ceil((target × N - points)/(5 - target))).
Worked example
One one-star review and three five-star reviews give 16/4 = 4 stars. Four more five-star reviews make 36/8 = 4.5 stars.
Advertisement
Frequently asked questions
Why might a platform show a different rating?
It may round, filter reviews, apply recency weights or use an undisclosed ranking method. This tool calculates a plain weighted mean.
Can I enter fractional review counts?
No. Each count represents whole reviews, including zero for an unused star level.
What if the target is already met?
The required extra count is zero. Target mode assumes no reviews are removed or changed.