Google Review Calculator
Find out how many 5-star reviews you need to reach your target Google rating, and how much a single bad review moves it.
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How the Google review calculator works
Your Google rating is the average of every review's star rating. Each new 5-star review pulls that average up a little, and the closer your target is to 5.0, the less each one moves it. To find how many you need:
5-star reviews needed = current reviews × (target − current rating) ÷ (5 − target)
Round the answer up to the next whole review.
Example: a business with 85 reviews at 4.2 stars wants a 4.5 rating. 85 × 0.3 ÷ 0.5 = 51 five-star reviews. Getting the same business to 4.8 takes 85 × 0.6 ÷ 0.2 = 255, five times as many, because each review moves a high average less.
Google displays your rating rounded to one decimal place, so a 4.45 average already shows as 4.5. The calculator gives you both numbers: the reviews needed for a true 4.5 average, and the fewer it takes before Google starts showing 4.5.
How much does one bad review hurt?
A single 1-star review hits hardest when you have few reviews. Here is what one 1-star review does to a business rated 4.6:
| Reviews before | Rating after one 1-star | Drop | Google shows |
|---|---|---|---|
| 10 | 4.27 | −0.33 | 4.3 |
| 25 | 4.46 | −0.14 | 4.5 |
| 50 | 4.53 | −0.07 | 4.5 |
| 100 | 4.56 | −0.04 | 4.6 |
| 250 | 4.59 | −0.01 | 4.6 |
5-star reviews needed to recover from one 1-star
The recovery count depends only on your rating, not on how many reviews you have: (rating − 1) ÷ (5 − rating), rounded up. The higher your rating, the more 5-star reviews it takes to win back the same ground.
| Your rating | 5-star reviews to get back |
|---|---|
| 4.0 | 3 |
| 4.2 | 4 |
| 4.5 | 7 |
| 4.7 | 13 |
| 4.8 | 19 |
| 4.9 | 39 |
The practical takeaway: the most reliable way to protect your rating is volume. Ask every customer for a review, every time, so one unhappy review is a small share of the total. See how your numbers compare in our Google review benchmarks by industry.
Frequently asked questions
How many 5-star reviews do I need to raise my Google rating?
Use this formula: reviews needed = current review count × (target rating − current rating) ÷ (5 − target rating), rounded up. For example, a business at 4.2 stars with 85 reviews needs 85 × 0.3 ÷ 0.5 = 51 five-star reviews to reach a 4.5 average. The calculator above does this for you.
How does Google calculate my star rating?
Google shows the average star rating of the reviews on your Business Profile, rounded to one decimal place. Every review counts equally, whether it is new or years old. Reviews that Google removes for breaking its policies no longer count.
How much does one 1-star review lower my rating?
It depends on how many reviews you already have. At 4.6 stars, one 1-star review drops a business with 10 reviews to about 4.27, but a business with 250 reviews only drops to about 4.59. Use the one bad review tab above to see your exact number.
How many 5-star reviews does it take to make up for one bad review?
Surprisingly, it does not depend on your review count, only on your rating. To recover from one 1-star review you need (current rating − 1) ÷ (5 − current rating) five-star reviews, rounded up: 3 at a 4.0 rating, 7 at 4.5, and 19 at 4.8.
Can I get back to a perfect 5.0 rating?
Your exact average can only be 5.0 if every review is 5 stars. Because Google rounds to one decimal, your profile shows 5.0 once your average reaches 4.95. After a 1-star review that takes a lot of 5-star reviews, which is why most strong businesses sit between 4.5 and 4.9.
Is it OK to ask only my happy customers for a Google review?
No. Google's review policy does not allow businesses to selectively ask for positive reviews or discourage negative ones. Ask every customer the same way. A steady stream of honest reviews from all of your customers is also the most reliable way to raise your rating over time.
Can I offer a discount or gift in exchange for a review?
No. Google prohibits offering incentives such as discounts, free products or gift cards in exchange for reviews, and the US Federal Trade Commission's rule on fake reviews also covers incentives tied to positive reviews. Make asking simple and consistent instead.
Does this calculator save my business data?
No. The calculator runs entirely in your browser. Nothing you type is sent to Feedback Guru, and you don't need an account.
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