Google rating calculator: how many 5-star reviews do you need?

A profile has N reviews averaging R. Add k reviews of 5 stars each, and the new average is (R × N + 5k) divided by (N + k). Set that equal to your target T and solve for k:

k = N × (T − R) ÷ (5 − T), rounded up

A profile with 220 reviews at 3.9, aiming at 4.3: that is 220 × 0.4 ÷ 0.7, which is 125.7, so 126 new 5-star reviews. The catch is in the denominator. The closer your target gets to 5.0, the smaller (5 − T) becomes, and the number runs away from you.

Very little, and that is worth saying plainly. Google’s help page describes the rating as the average of all ratings published on Google. It does not publish a weighting, a recency effect, or any formula beyond that average.

That makes this calculator different from our TrustScore calculator. Trustpilot says openly that its score is not a plain average, so that tool is an estimate of scale. Here the arithmetic is the arithmetic Google describes.

Two things still move the number away from the sum. A profile shows the rating rounded to one decimal place. And a new or edited review can take up to two weeks to appear in the rating, so a quiet week after a push is normal rather than a sign that something is wrong.

For a rating to show at all, you need reviews on the profile, and the arithmetic above tells you the rest. What nobody can tell you is a target number that wins customers, because no platform publishes one.

What is published is narrower and more useful. Google shows a store rating on text ads only when the rating is 3.5 stars or higher, which is a real threshold with money attached. And in a study of product ratings on retail sites, purchase likelihood peaked between 4.0 and 4.7, not at 5.0.

So the honest version is a band rather than a number: above the 3.5 that Google’s ads need, and inside the range where buyers stop being suspicious. Everything past that is a slower return on the same work.

Removal, and it is not close. A new 5-star review adds one number to the top of the average. A removed 1-star review takes a number out of both the top and the bottom, so it moves the rating twice as hard.

The limit is what can be removed. Only reviews that break one of Google’s content policies come down, and Google decides every case. On most profiles that is a minority of the 1-star reviews. A real customer describing a real problem stays, however harshly they put it.

Which is why the answer for most brands is both: ask everyone, inside the rules, and report the reviews that break one. Our guide to getting more Google reviews covers the first, and Google review removal covers the second. The rating recovery planner shows both at once, month by month for a year. The prices are on the pricing page.