5-Star Rating Calculator
Enter how many 5-, 4-, 3-, 2-, and 1-star ratings you have to get the weighted average out of 5, the total, the share that are positive, and how many more 5-star ratings it takes to reach a target.
Example: with Number of 5-star ratings 120 · Number of 4-star ratings 45 · Number of 3-star ratings 20 · Number of 2-star ratings 8 · Number of 1-star ratings 12 → Weighted star average: 4.23 out of 5.
- Total ratings205 ratings
- Positive (4-5 star)80.5% rated 4 or 5 stars
- To reach target109 more 5-star ratings to reach 4.50
Computed by the calculator below using its default values. Change any input to see your own numbers.
A star rating is a volume-weighted mean; the low scores pull hardest when you have few reviews.
How the star average is built
A star rating is just a weighted mean. Each review contributes its star value, and the average is the total stars divided by the number of reviews: (5·n5 + 4·n4 + 3·n3 + 2·n2 + 1·n1) / total. That is why a wall of 5-star reviews can still be dragged down by a handful of 1-star ones. Every rating counts equally, and the low scores sit far from the top.
What it takes to move the number
Once you have a lot of reviews, the average gets stubborn. To raise it you need enough new top ratings to outweigh all the history. The calculator solves for that directly: the additional 5-star ratings n needed to reach a target T is n = (T·total - stars) / (5 - T), rounded up. As T approaches 5 the denominator shrinks and the count explodes, which is why near-perfect averages are so hard to defend.
How it’s calculated
Weighted average = (5·n5 + 4·n4 + 3·n3 + 2·n2 + 1·n1) / (n5 + n4 + n3 + n2 + n1). To reach a target average T using additional 5-star ratings, solve (currentStars + 5n) / (currentCount + n) ≥ T, giving n = ceil((T·count - stars) / (5 - T)). Percent positive counts the 4- and 5-star ratings.
Every rating is weighted equally and treated as a whole star. Platforms that weight by recency, verified purchase, or reviewer trust will show a different public number.
What a star average signals
| Average | Typical read |
|---|---|
| 4.5 - 5.0 | Excellent; top tier |
| 4.0 - 4.4 | Good; most buyers satisfied |
| 3.5 - 3.9 | Mixed; read the reviews |
| 3.0 - 3.4 | Weak; recurring complaints |
| Below 3.0 | Poor; proceed with caution |
Common marketplace conventions; individual platforms weight recency and volume differently.
Common mistakes
- Averaging the star labels 1 through 5 instead of weighting by how many reviews sit at each level.
- Chasing a target above 5, or one already met. The tool flags both instead of returning a strange number.
- Forgetting that volume protects an average: the more reviews you have, the more new 5-star ratings it takes to move it.
Frequently asked questions
How is a 5-star average calculated?
Multiply each star level by its number of reviews, add those up, and divide by the total reviews: (5·n5 + 4·n4 + 3·n3 + 2·n2 + 1·n1) / total. It is a weighted mean, not an average of the labels 1 through 5.
How many 5-star reviews do I need to raise my rating?
Use n = (target·total - current stars) / (5 - target), rounded up. The calculator shows this figure for whatever target you enter, and warns you when the target is already met or impossible.
Why is my average stuck even after good reviews?
Because it is weighted by volume. With hundreds of existing reviews, a few new 5-star ratings barely move the total, so the average changes slowly.
What does percent positive mean here?
It is the share of reviews that are 4 or 5 stars, a quick read on overall sentiment that ignores the exact average.
Can I use this for things other than products?
Yes. Any 1-to-5 rating works the same way: employees, courses, restaurants, or app store reviews all use this weighted-average math.