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Amazon Rating Calculator

Calculate how many 5-star reviews you need to reach your desired Amazon product rating.

Practical Example

Let's suppose we have a product with the following details:

  • Current Average = 3.93
  • Current Count = 57
  • Desired Average = 4.5

Plugging those values into the equation:

x = (4.5 − 3.93) × 57 / (5 − 4.5)

Let's calculate it:

x = 0.57 × 57 / 0.5

x = 32.49 / 0.5

x = 64.98

And since you can't have a fraction of a rating, you would need at least 65 additional 5-star ratings to reach an average of 4.5.

Math Explanation

To determine the number of additional 5-star ratings you need to achieve a desired average rating, we use simple algebra. Here's a step-by-step explanation:

1. Define the Variables:

  • Let Current Average be the current average rating
  • Let Current Count be the current number of ratings
  • Let Desired Average be the desired average rating
  • Let x be the number of additional 5-star ratings needed

2. Set up the Equation:

  • The total sum of the ratings currently is Current Average × Current Count
  • The total sum after adding x more 5-star ratings: (Current Average × Current Count) + (5 × x)
  • The total number of ratings after adding x: Current Count + x

3. Create the Equation:

Desired Average = (Current Average × Current Count) + (5 × x) / (Current Count + x)

4. Solve for x:

After algebraic manipulation, we arrive at the final formula:

x = (Desired Average - Current Average) × Current Count / (5 - Desired Average)

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