Google rating calculator
See how many five-star reviews you need to reach 4.5, 4.8 or any target, how much one bad review costs you, and what your Google rating would be if fake reviews came down.
How many 5-star reviews cancel out a 1-star review?
Every one-star review pulls your average down, and the pull gets stronger the better your rating is. This table shows how many five-star reviews it takes to get back to where you were after one new one-star review.
| Your rating | Five-stars to cancel one one-star |
|---|---|
| 3.5 | 2 |
| 3.8 | 3 |
| 4.0 | 3 |
| 4.2 | 4 |
| 4.4 | 6 |
| 4.5 | 7 |
| 4.6 | 9 |
| 4.7 | 13 |
| 4.8 | 19 |
| 4.9 | 39 |
That is why a handful of fake one-star reviews can undo months of good work, and why getting rule-breaking reviews removed is often quicker than trying to outnumber them. The review removal checker tells you whether a review is likely to qualify.
How many reviews to reach 4.5 stars
Five-star reviews needed, in a row, to show 4.5 on Google, by starting rating and number of reviews.
| Starting rating | 25 reviews | 50 reviews | 100 reviews | 250 reviews |
|---|---|---|---|---|
| 3.8 | 30 | 60 | 119 | 296 |
| 4.0 | 21 | 41 | 82 | 205 |
| 4.2 | 12 | 23 | 46 | 114 |
The maths behind the calculator
Google displays your rating to one decimal place, so a true average of 4.45 already shows as 4.5. The calculator solves for the smallest number of five-star reviews, n, where your new average reaches the target minus 0.05:
n = reviews x (target - 0.05 - rating) / (5 - (target - 0.05)), rounded up.
For removals it takes the total stars (rating x reviews), subtracts one star for each one-star review removed, and divides by the reviews left. Google does not publish its exact method, so treat every figure as a close estimate rather than a promise.
Ways to improve your Google rating that are allowed
- Ask every customer, not just the happy ones, with a direct link to your review form. Selectively asking only happy customers is called review gating and Google does not allow it.
- Never offer anything in return for a review or for changing one. It breaks Google's policy and UK consumer law.
- Reply to every negative review calmly. Our guide to replying to negative Google reviews has templates.
- Report reviews that break the rules, such as fake, competitor or abusive reviews, and get negative Google reviews removed when they qualify.
Frequently asked questions
How many 5-star reviews does it take to cancel a 1-star review?
It depends on your current rating. At 4.0 it takes 3 five-star reviews to cancel one one-star, at 4.5 it takes 7, and at 4.8 it takes 19. The higher your rating, the more a single one-star review costs you.
How does Google calculate my star rating?
Google shows your rating to one decimal place. It does not publish its exact formula, so this calculator treats the rating as the simple average of all star ratings, rounded to one decimal. That matches what most businesses see, but treat the result as a close estimate.
Why has my rating not changed after a new review?
Google can take a while to update the rating, and a new review can also be held back while it is checked. With many reviews, one more five-star may not be enough to change the rounded number.
Is it allowed to ask customers for reviews?
Yes, as long as you ask everyone, not just happy customers, and never offer anything in return. Offering a discount or gift for a review breaks Google's rules and, in the UK, can break consumer law. See fake reviews law in the UK.
Would removing fake reviews really change my rating that much?
On a small profile, yes. A business with 21 reviews averaging 3.9 that has four fake one-star reviews removed goes to about 4.6. On a profile with hundreds of reviews the effect is smaller, which the calculator shows.