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Google Review Calculator: how many 5-star reviews do you need?

Type in where you are and where you want to be. This works out exactly how many more 5-star reviews it takes — and shows you the arithmetic, so you can check it yourself. Free, no account, nothing to install.

What this is actually solving

Your Google rating is a plain average. If you have c reviews at an average of r stars, your reviews are worth r × c star-points in total. Every new 5-star review adds 5 points and one more review, so after n of them your average is:

(r × c + 5n) ÷ (c + n)

Set that to be at least your target t and rearrange, and all of the algebra collapses to one line:

n = ⌈ c × (t − r) ÷ (5 − t) ⌉

Read it out loud and it is common sense. The top is how far behind you are, counting every review you already have. The bottom is the headroom a 5-star review has left above your target — and that is why 4.8 is so much harder than 4.3. Chasing 4.3 leaves 0.7 of headroom per review; chasing 4.8 leaves 0.2, so each review does less than a third of the work.

Reaching 4.5 and displaying 4.5 are not the same thing

Google rounds to one decimal place, so a profile displays 4.5 from a true average of 4.45 upwards. This calculator gives you the honest, conservative number: the point where you have genuinely reached your target, not the point where it merely rounds up. Underneath the answer it also tells you the smaller number where the target first appears on your profile, clearly labelled, so you know both.

One caveat we cannot fix for you, and would rather say out loud: the rating you typed in has already been rounded by Google. A profile showing 4.2 is somewhere between 4.15 and 4.25, so the true answer can land a review either side of ours. If you want the exact figure, count your 1s, 2s, 3s, 4s and 5s and add them up.

The uncomfortable part: bad reviews get more expensive as you improve

Work out the cost of a single 1-star review — how many new 5-star reviews it takes just to get back to where you were — and the review count cancels out completely. It only depends on your rating:

⌈ (r − 1) ÷ (5 − r) ⌉

• At 4.0, one 1-star review costs you 3 new 5-star reviews.
• At 4.5, it costs 7.
• At 4.8, it costs 19.

Which is the real argument for asking every customer from your very first job: reviews are cheapest to earn when you have none, and a steady flow is what absorbs the occasional bad day. Google also weights recent reviews more heavily than old ones, so a profile with 200 reviews and nothing in the last year is weaker than the arithmetic alone suggests.

Fair warning about the shortcuts

There is no legitimate way to shortcut this. Google removes reviews that break its policies, not reviews you dislike; buying reviews is against Google's policy and gets profiles suspended; and review gating — only asking for a review when someone seems happy — is explicitly prohibited. The arithmetic above is the whole game: ask everyone, every time, and make it take ten seconds.

Star rating calculator, review score calculator, same arithmetic

People look for this tool under a lot of names — star rating calculator, Google review score calculator, 5-star review calculator, review average calculator. They are all the same sum, and this page does all of them: it takes the rating you have now, the number of reviews behind it, and the rating you want, and returns how many 5-star reviews close the gap.

Two things it deliberately does not do. It does not estimate what Google displays as your headline number without telling you — the rounding answer is shown separately and labelled, because the two differ by a few reviews and quietly conflating them would flatter the result. And it does not look your business up, which is why it is free and instant: nothing here calls an API.

Once you know the number, the next problem is collecting them. Generate your direct Google review link so customers land on the star picker in one tap, then put it on a printed QR code for the van and the invoice.

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