Free tool

Google review calculator

Work out how many 5-star reviews you need to reach your target Google rating, for one location or every branch at once. Free, no sign-up.

Akili tracks every branch's rating, reviews and reply rate automatically, and shows which fixes will lift your rating most.

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How are Google ratings calculated?

Google says a business's review score is the average of all the ratings published on Google for it (Google help). Every review counts equally, whether it was left last week or five years ago. Google shows the average to one decimal place, so an average of 4.45 displays as 4.5, and it can take up to two weeks for a new review to change the score.

How to calculate how many 5-star reviews you need

Use this formula, where N is your current number of reviews, R is your current rating and T is the average you need:

5-star reviews needed = N × (T − R) ÷ (5 − T)

Round the answer up. To show a rating on Google rather than reach it exactly, use T = target − 0.05. For example, to show 4.5 you need an average of 4.45.

Worked example. A café has 200 reviews averaging 4.2 and wants to show 4.5. That's 200 × (4.45 − 4.2) ÷ (5 − 4.45) = 200 × 0.25 ÷ 0.55 = 90.9, so it needs 91 new 5-star reviews, with no new lower ratings. With only 50 reviews, it would need 23. The more reviews you already have, the more it takes to move the number.

How the calculator works

For one location, the calculator works out how many new 5-star reviews lift your average to the point where Google shows your target. It assumes no new lower ratings arrive in the meantime, so treat the number as a minimum.

For several branches, it weights each branch by its number of reviews to give your combined rating, the figure a brand-wide profile or a head-office report would show. It then ranks branches by drag: how far each sits below the median branch, multiplied by its share of all reviews. Our guide to why one branch drags down your whole brand rating explains the method with worked examples.

What rating do customers look for?

Small differences in rating cross real lines for customers. In BrightLocal's 2026 survey of 1,002 US adults, 68% said they would only use a business rated four stars or more, and 31% would only use one rated 4.5 or more (BrightLocal, 2026). The same survey found 74% looked for reviews from the last three months, so a steady flow of recent reviews matters as much as the average.

How to get more 5-star reviews, the right way

  1. Ask every customer, not only happy ones. A QR code at the till, a line on the receipt or a follow-up email after delivery all work. Asking only satisfied customers can count as presenting reviews in a misleading way under UK rules.
  2. Never offer anything in return. Google prohibits incentives for reviews, and UK rules ban reviews that hide one (Google help).
  3. Reply to every review. A clear review response policy keeps replies quick and consistent across sites.
  4. Fix the theme behind your low reviews. More 5-star reviews lift a rating for a while; fixing the cause keeps it there. Our guide to tracking Google reviews across every branch shows how to find it.

Frequently asked questions

How are Google reviews calculated?

Google says a review score is the average of all ratings published on Google for that business. It shows the average to one decimal place, and it can take up to two weeks for a new review to change it.

How many 5-star reviews do I need to go from 4.2 to 4.5?

It depends on how many reviews you already have. With 200 reviews at 4.2, you need about 91 new 5-star reviews, with no new lower ratings, to show 4.5 on Google. With 50 reviews you need about 23. Use the calculator above for your own numbers.

How do you work out a combined rating across branches?

Weight each branch by its number of reviews: multiply each branch rating by its review count, add them up, and divide by the total number of reviews. Busy branches count for more, which is why one busy branch can drag down the whole brand.

Can I offer a discount or gift for a 5-star review?

No. Google prohibits offering anything in return for reviews, and UK rules ban reviews that hide an incentive. Ask every customer, not only happy ones, and make leaving a review easy.

Does replying to reviews improve your rating?

It can. Researchers found that hotels that started replying to reviews received 12% more reviews and gained 0.12 stars on average.

Sources

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