Mathematical Formula for Star %

Someone here offered a common-sense approach to checking our star rating and I can’t find it now. Could it be posted again, if I promise to write it down?

I have 151/154 5-star reviews and tried to calculate the %this way:

Total # of stars possible 770
divided by my total # of stars 755

I’m either using my calculator upside, not understanding the result or - most likely - am unclear on the concept!

Any help would be greatly appreciated!


No- you multiply the number of 5 star reviews, the number of 4* reviews , etc. add the totals and divide by the total number of reviews.


150 x 5* =750
5 x 4*= 20
1 x 3*= 3

773 (total number of stars earned) divided by 156 (total number of reviews)= 4.955

To make this more visual and simple for you, rather than an abstract formula, so you can hopefully understand it:

You put out a plate of 12 cookies in front of 3 children. One child immediately grabs 5 cookies, one grabs 4, leaving the last child with 3.
You say, “No, no, kids- you have to divide those cookies up evenly.”

1 child has 5 cookies = 5
1 child has 4 cookies = 4
1 child has 3 cookies = 3

Total number of cookies- 12. Divided by 3 children= 4 cookies each.

Now imagine the number of children are the number of reviews and the cookies are stars,- the number of cookies they each should get is the star average.


Seems related to your other post, but I don’t see all of the necessary data. What is needed is the total number of reviews and the number that were 5-star, 4-star, 3-star, 2-star, and 1-star overall. I’m not sure if your listing is in your profile, but even if it is, I don’t think I can see it without a lot of work.

So kind, thank you! Very clear - and this time I’ll write it down it down😉


I’ll try Muddy’s formula and report my findings- thanks for response :blush:


You’ve calculated: 151x5/154x5=151/154 =98% which is the % of your reviews which are 5* so will be a number <=100%. You want to calculate something like:
(151x5+3x4)/154=767/154=4.98 which is the weighted average of how many stars you receive assuming 151 of your reviews were 5* and the other 3 were 4*.

Like @muddy Option 2:
755 / 154 = 4.90

Total stars / #reviews= avg star rating