Book Rating Average Calculator (Star Ratings and Weighted Score)

How to use the Book Rating Average Calculator (Star Ratings and Weighted Score)

1. Enter how many ratings each star level received.
2. Optionally set C, the typical rating you compare against, and m, how many ratings before you trust the average.
3. Read the average, the percentage split and the weighted score.
4. Try a book with few ratings to see the weighted score move toward C.

Example

Worked example (400, 350, 150, 60 and 40 ratings from 5 stars to 1 star)

• Total ratings: 1,000
• Average: (2,000 + 1,400 + 450 + 120 + 40) ÷ 1,000 = 4.01
• Weighted score with C = 3.8 and m = 100: (1000 ÷ 1100) × 4.01 + (100 ÷ 1100) × 3.8 = 3.99
• A book with 5 ratings, all 5 stars: Average 5.00, weighted score 3.86

Limitations

• The weighted score depends on the C and m values you choose. They are not published figures from any site.
• Star ratings are subjective, and a review site’s own score may use other adjustments.
• Half-star ratings are not supported. Round them to a whole star first.

Sources

About this tool

The Book Rating Average Calculator takes the number of 5, 4, 3, 2 and 1-star ratings and returns the average rating, the share of each star and a weighted score. The weighted score pulls the average toward a typical rating when there are only a few ratings, which is a fairer way to compare a book with 12 ratings to one with 12,000. It works for books, films, products and anything else rated out of five stars.

Also searched for as: average star rating calculator, goodreads rating calculator, weighted rating calculator, bayesian average rating, rating distribution calculator, five star rating average.

Book Rating Average Calculator (Star Ratings and Weighted Score) is part of ToolStack Hub's Calculators. It runs entirely in your browser, which keeps your data private and makes results instant. There is nothing to install and no account to create. There is no usage limit.

Frequently asked questions