How many 5 star reviews cancel out a 1 star Google review?

Why the word cancel is the problem

The question assumes a scoreboard, where a positive offsets a negative and the two disappear. A Google rating is not a scoreboard, it is an arithmetic mean, and then it is rounded to one decimal place before anyone sees it. Nothing is ever taken out of that sum by adding to it. The 1 star stays in the average, and new 5 stars only make it a smaller share of the total.

That rounding matters more than most owners realise. The number a customer sees is one decimal, so the only thing worth asking is how many 5 stars it takes to move that displayed figure, not the exact average sitting behind it.

The formula, and what it tells you

If you have n reviews adding up to a total of S, and you want the displayed rating to reach T, the number of 5 star reviews you need is (T times n, minus S) divided by (5 minus T). That divisor is the whole story: the closer T is to 5, the smaller the divisor, and the faster the required number runs away from you.

Which is why recovering the decimal you just lost is usually cheap, and getting back to a straight 5.0 usually is not.

Four worked cases

Each of these starts with one 1 star landing on a listing, and asks what it takes to recover from there.

• 10 reviews, all 5 star, so 5.0 displayed. One 1 star drops it to 4.6. It takes 17 more 5 stars to display 4.9 again, and more than 70 to display 5.0.
• 20 reviews, all 5 star, so 5.0 displayed. One 1 star drops it to 4.8. It takes 7 more 5 stars to display 4.9, and around 60 to display 5.0.
• 50 reviews averaging 4.8. One 1 star drops it to 4.7. It takes 6 more 5 stars to get 4.8 back.
• 100 reviews averaging 4.9. One 1 star changes the displayed rating not at all. It stays 4.9.

The number that actually protects you is your review count

Read those four cases in order and the pattern is not about 5 stars at all. It is that a new listing is fragile and an established one is not. At 10 reviews a single 1 star costs you four tenths of a star. At 100 reviews the same 1 star costs you nothing anyone can see.

So the useful version of this question is not how many 5 stars cancel a 1 star. It is how many reviews you need before a 1 star stops being an event. For most listings that is somewhere near 100, and getting there is a slower, duller job than chasing any single review.

The faster lever, where it applies

One thing does take a 1 star out of the average rather than diluting it, and that is Google removing the review. If the review breaks a published content policy, and the report names the clause it breaks, the average returns to exactly what it was before. That is the only real cancel in this subject, and Google makes the final call on every removal.

It only applies where there is a genuine policy match. Someone who was never a customer, a review about a different business, an advertisement, an attack on a member of staff rather than an account of a visit: those are policy questions. A customer who was disappointed and said so is not, however unfair the star count feels.

Two ways owners make this worse

The first is asking only the customers likely to be happy. That is review gating, it is against Google's policy, and it produces the too-good-to-be-true pattern that makes buyers suspicious of a 5.0 in the first place.

The second is buying reviews to bulk the average out. Beyond being illegal advertising in the US and elsewhere, a burst of unconnected accounts praising one business is the exact signature Google's abuse systems look for, and the risk lands on the whole listing rather than on the one review you were unhappy about.