How do I work out how many 5-star reviews I need?

Multiply your rating by your number of reviews to get your total stars. The 5-star reviews you need are (target rating × reviews − total stars) ÷ (5 − target rating), rounded up. A 4.2 rating from 180 reviews is 756 stars, so reaching 4.4 takes (792 − 756) ÷ 0.6 = 60 five-star reviews.

How much does one 1-star review hurt my rating?

Less the more reviews you have. At 4.6 from 50 reviews, one 1-star review takes the average to about 4.53; at 4.6 from 500 reviews it moves to about 4.59. Cancelling it out takes (rating − 1) ÷ (5 − rating) five-star reviews: 9 at a 4.6 rating.

Why is the answer an estimate?

Google shows your average to one decimal place, so the rating you enter is already rounded. The true average could sit a little above or below it, which can move the answer by a few reviews either way. Reviews Google removes for breaking its policies also change your count.

Can I ask guests for Google reviews?

Yes. Google lets businesses ask customers for reviews, but not pay or reward them for reviews, and not ask only the guests you expect to be happy. In the UK, the Digital Markets, Competition and Consumers Act 2024 also bans fake reviews and incentivised reviews that are not disclosed.

Google review rating calculator

Enter the rating and review count Google shows for your restaurant. See how many 5-star reviews it takes to reach the next step up, and how many it takes to win back a single 1-star review.

Free to use
No sign-up or email
Your figures stay in your browser

A server clearing plates beside a couple at a window table while one of them types on a phone.

Example figures are filled in. Change any field to use yours.

Your Google rating

stars

As shown on your Google Business Profile.

Number of reviews

Target rating

stars

Result

5-star reviews to reach 4.5: 108; Then 288 reviews in total.
One 1-star review takes you to: 4.18
5-star reviews to cancel one 1-star: 4

Each step up from 4.2

4.326
4.460
4.5108 (your target)
4.6180
4.7300
4.8540
4.91,260

Estimates: the rating Google shows is rounded to one decimal place, so the true answer can be a few reviews either way.

How the calculator works

Google shows the average of your star ratings. Every 5-star review pulls that average up a little, and by less each time as you get closer to 5.

Total stars = your rating × your number of reviews
5-star reviews needed = (target rating × reviews − total stars) ÷ (5 − target rating), rounded up
Rating after them = (total stars + 5 × new reviews) ÷ (reviews + new reviews)
5-star reviews to cancel one 1-star review = (rating − 1) ÷ (5 − rating), rounded up

Worked example

A restaurant shows 4.2 stars from 180 reviews, which is 756 stars in total.

Target	Calculation	5-star reviews needed
4.3	(774 − 756) ÷ 0.7	26
4.4	(792 − 756) ÷ 0.6	60
4.5	(810 − 756) ÷ 0.5	108

Each step costs more than the last. At 4.2, one 1-star review needs four 5-star reviews to cancel it out; at 4.6 it needs nine.

Why the last steps are the hardest

The gap between a 5-star review and your average shrinks as the average rises. At 3.8 a new 5-star review is 1.2 stars above average and lifts it quickly; at 4.7 it is only 0.3 above and barely moves it. That is why replying well to the reviews you get, and fixing what they complain about, matters as much as collecting more.

More reviews, the fair way

Ask at the right moment. When guests are paying and the meal went well, a short spoken ask works better than a sign.
Make it one tap. A short link or QR code to your review form on the bill, a table card or a follow-up email removes the search.
Ask everyone. Google's rules do not allow asking only the guests you expect to be happy, or offering anything in return for a review.
Reply to every review. Thank the good ones by name and answer the bad ones calmly with what you changed. Future guests read the replies.

Frequently asked questions

How do I work out how many 5-star reviews I need?: Multiply your rating by your number of reviews to get your total stars. The 5-star reviews you need are (target rating × reviews − total stars) ÷ (5 − target rating), rounded up. A 4.2 rating from 180 reviews is 756 stars, so reaching 4.4 takes (792 − 756) ÷ 0.6 = 60 five-star reviews.
How much does one 1-star review hurt my rating?: Less the more reviews you have. At 4.6 from 50 reviews, one 1-star review takes the average to about 4.53; at 4.6 from 500 reviews it moves to about 4.59. Cancelling it out takes (rating − 1) ÷ (5 − rating) five-star reviews: 9 at a 4.6 rating.
Why is the answer an estimate?: Google shows your average to one decimal place, so the rating you enter is already rounded. The true average could sit a little above or below it, which can move the answer by a few reviews either way. Reviews Google removes for breaking its policies also change your count.
Can I ask guests for Google reviews?: Yes. Google lets businesses ask customers for reviews, but not pay or reward them for reviews, and not ask only the guests you expect to be happy. In the UK, the Digital Markets, Competition and Consumers Act 2024 also bans fake reviews and incentivised reviews that are not disclosed.

Results are estimates for planning, based only on the figures you enter. They are not financial, tax or legal advice. The calculation runs in your browser and TablePort does not see or save the figures you enter.

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