Google review calculator, to the decimal

How many 5-star reviews you need

The calculator works out your total stars, then finds the smallest number of 5-star reviews that lifts your average high enough for Google to show the rating you want. Your total stars is your rating times your review count: 40 reviews at 4.3 is 172 stars.

Google shows your rating to one decimal place, so you do not need an average of exactly 4.5 to see 4.5 on your profile. Anything from 4.45 upwards rounds to it. So for a 4.5 target, the calculator counts the reviews needed to reach 4.45. It also tells you how many it would take to reach the exact figure, which is always more.

A worked example: a roofer with a 4.3 rating from 40 reviews, aiming for 4.5.

• Starting point: 4.3 × 40 = 172 stars.
• After 10 more 5-star reviews: 222 stars from 50 reviews is 4.44. That still shows as 4.4.
• After 11: 227 stars from 51 reviews is 4.45. Google shows 4.5. So the answer is 11.
• Exact 4.5: 252 stars from 56 reviews is 4.50, so 16 reviews to reach the true average.
• One 1-star review instead: 173 stars from 41 reviews is 4.22, and the profile drops to 4.2.

The rating Google shows and your real average

Google says your review score is the average of all ratings published for your business on Google, on a scale of 1 to 5. Search and Maps show it to one decimal place. Google does not publish its rounding rule, so the calculator assumes ordinary rounding: 4.45 and above shows as 4.5, and 4.44 shows as 4.4. Treat a result that lands exactly on the halfway point as one review short.

The same help page says a new review can take up to two weeks to show in your score. If the number on your profile has not moved after a good week, give it time before you assume something is wrong.

There is one more catch. The rating you type in is itself rounded. A profile showing 4.3 from 40 reviews could really hold anything from 4.25 to just under 4.35, which is between 170 and 174 stars. Reaching 4.5 from there takes anywhere from 8 to 15 more 5-star reviews. If you know your exact star count, divide it by your number of reviews and type the result to two decimal places. On a big profile the difference is small.

What one 1-star review does to your rating

A single 1-star review hits a small profile hard and a big one barely at all. The calculator shows you which side of that line you are on.

Take a new electrician with a perfect 5.0 from 20 reviews. One 1-star review gives 101 stars from 21 reviews, an average of 4.81, and the profile shows 4.8 from then on. It also means an exact 5.0 average is gone for good, because every later review can only pull the average towards 5, never back to it. The calculator will say so if you ask it for 5.0.

Now take a heating firm with a 4.8 from 200 reviews: 960 stars. One 1-star review makes it 961 from 201, an average of 4.78, and the profile still shows 4.8. But moving that firm up to a 4.9 on show takes 67 more 5-star reviews, and the exact 4.9 takes 200. Big profiles are hard to dent and slow to lift.

When a bad review does land, reply to it calmly and in public. Our guide to answering a bad review covers the wording. You can report any review to Google, but only ones that break Google's policies are removed. If you think a rival is behind it, see how to handle fake reviews left by a competitor.

Getting the reviews without breaking the rules

The number the calculator gives you is a count of real customers to ask, not a target to fill any way you can. The only safe way to close the gap is to ask every customer, every time, and let the reviews land where they land.

Google's contribution policy rules out rewards of any kind for a review (payment, discounts, free goods or services), discouraging negative reviews, and asking for reviews only from people likely to be happy. It also rules out giving staff a review quota, and reviews from anyone with a conflict of interest, such as employees. Breaking these rules can get reviews taken down. In the UK, fake reviews and hidden incentivised reviews are also a consumer law matter: the CMA's guide for businesses publishing reviews explains where the line is.

• Do: send your review link to each customer when they sign the job off. The Google review link generator makes the link and the message.
• Do: ask in person at the end of the job, without pressing them to do it there and then, and follow up with the link the same day.
• Do not: ask "were you happy?" first and only send the link to those who say yes.
• Do not: knock money off the bill, enter people in a draw or add a free extra for a review.
• Do not: set your team a monthly review target, or ask family and friends to fill the gap.

Which rating to aim for

Aim for the next step up on show, not a perfect score. Going from 4.3 to 4.5 is a target you can hit in a few months of asking everyone. Going from 4.8 to 5.0 on a busy profile is usually out of reach, and chasing it is how people end up tempted to filter who they ask.

A run of recent reviews also does more for you than a decimal point. Someone choosing between two firms reads the dates and the latest few comments as well as the stars. A profile with a 4.7 and reviews from last week often looks more alive than a 5.0 whose newest review is a year old, which is why we say a steady trickle beats a batch.

So use the number as a planning figure. If you finish 15 jobs a month and roughly a third of customers leave a review when asked, 11 reviews is a little over two months away. Run the calculator again when you get there.

Common questions