Free tool
How many 5★ reviews do you need?
Enter your Google rating, your number of reviews and the rating you want. See how many 5-star reviews get you there — and how many 1-star reviews would pull you below it.
For Google to show 4.3★
8
more 5★ reviews in a row, with no lower ones in between. Your average would be about 4.25, which Google shows as 4.3★.
To fall below 4.2★ (what Google shows now)
2
1★ reviews in a row would bring your average to about 4.14, and Google would show 4.1★. Each one deserves a careful reply.
Google shows your rating rounded to one decimal: it shows 4.8 from an average of 4.75. Because the rating you typed is itself rounded, your real average may be a little higher or lower, so treat these numbers as a close guide. Nothing you type here leaves your browser.
How it works
Your average is your total stars divided by your number of reviews. With a 4.2 rating over 120 reviews you hold 504 stars. Each new 5★ review adds 5 stars and one review, so after 55 of them you have 779 stars over 175 reviews — an average of 4.45, which Google rounds and shows as 4.5.
The lesson in the numbers: the more reviews you already have, the slower your rating moves — in both directions. A steady flow of reviews, and a calm reply to the bad ones, matters more than any single review.
How Google works out your star rating
Google's own help page puts it simply: your score is the average of every rating published on Google for your business. Add up the stars from each published review, divide by how many reviews there are, and you have it. Google displays the result to one decimal place. It does not publish the exact rounding rule, so this calculator rounds to the nearest tenth.
| Reviews | Total stars | Average | Google shows |
|---|---|---|---|
| 4 reviews: 2 × 5★, 1 × 4★, 1 × 3★ | 10 + 4 + 3 = 17 | 17 ÷ 4 = 4.25 | 4.3 |
| 12 reviews: 8 × 5★, 2 × 4★, 1 × 3★, 1 × 2★ | 40 + 8 + 3 + 2 = 53 | 53 ÷ 12 = 4.42 | 4.4 |
| 60 reviews: 40 × 5★, 12 × 4★, 5 × 3★, 3 × 1★ | 200 + 48 + 15 + 3 = 266 | 266 ÷ 60 = 4.43 | 4.4 |
- One displayed number covers a range. A shown 4.3 can be anything from 4.25 up to just below 4.35, so two businesses with the same stars on Maps can be several reviews apart.
- New reviews are not reflected instantly. Google says the score can take up to two weeks to update after a review is posted.
Why every tenth costs more than the last
A new review is averaged in with all the reviews you already have, so the bigger your review count, the less any single review can move it. To be shown as a rating T, your real average only has to reach T − 0.05. With N reviews averaging R, the number of new 5-star reviews you need is:
n ≥ N × (T − 0.05 − R) ÷ (5 − (T − 0.05)), rounded up
For example, 200 reviews averaging 4.5 with a target of 4.6: the average has to reach 4.55, so n ≥ 200 × 0.05 ÷ 0.45 = 22.2, which means 23 more 5-star reviews.
| From → to | 25 reviews | 100 reviews | 400 reviews |
|---|---|---|---|
| 4.0 → 4.1 | 2 | 6 | 22 |
| 4.3 → 4.4 | 2 | 8 | 31 |
| 4.6 → 4.7 | 4 | 15 | 58 |
| 4.8 → 4.9 | 9 | 34 | 134 |
New 5-star reviews in a row, starting exactly at the first value.
- Volume slows everything down. The reviews you need grow in step with the reviews you have: four times the reviews, roughly four times the effort.
- Near the top, each review lifts less. A 5-star review pulls the average up by the gap between 5 and where you are. At 4.0 that gap is a full star; at 4.8 it is a fifth of one, which is why the last step in the table costs several times the first.
The same arithmetic works against you. With 30 reviews at 4.8, one 1-star review takes the average to 4.68, shown as 4.7. With 150 reviews, the same review only moves it to 4.77, and Google still shows 4.8.
How many 5-star reviews cancel out one 1-star?
Enough to bring the average back to where it was: (R − 1) ÷ (5 − R), rounded up. Notice what is missing: your review count. Undoing one 1-star review costs the same at 20 reviews as at 2,000. What volume changes is how much the 1-star hurt in the first place.
| Your average | 5-star reviews to undo one 1-star |
|---|---|
| 4.0 | 3 |
| 4.3 | 5 |
| 4.5 | 7 |
| 4.7 | 13 |
| 4.9 | 39 |
That is the real case for a steady flow of reviews: it keeps a bad day from showing on your profile at all, rather than leaving you to repair it afterwards.
Why your own math may not match Google
- Only published reviews count. A review Google removed or never published is not in the average.
- Rounding. You see one decimal; the real average behind it can sit up to 0.05 either side.
- Timing. A new review can take up to two weeks to show in the score.
Can you reach 5.0?
An exact 5.00 needs every published rating to be a 5: once one lower rating is in, more 5-star reviews get you closer forever without arriving. But Google shows one decimal, so an average of 4.95 already displays as 5.0, and that is reachable. For example, 50 reviews averaging 4.9 need 50 more 5-star reviews to be shown as 5.0. The same rounding helps lower down: to be shown as 4.5 you need 4.45, not 4.5.
Want the full background, with sources? Read our guide on how Google star ratings work.
Questions
How does Google calculate my star rating?
Google's help page says the score is the average of all ratings published on Google for your business: total stars divided by the number of published reviews, displayed to one decimal place. Google says it can take up to two weeks for the score to update after a new review.
Why doesn't my rating match my own calculation?
Usually one of three things: a review Google removed or never published is not in the average, the score you see is rounded to one decimal, or a recent review has not been counted yet (Google says updates can take up to two weeks).
Do 4-star reviews raise my Google rating?
Only when your average is below 4.0. Every new rating pulls the average towards its own value, so a 4-star review lifts a 3.7 profile and slightly lowers a 4.6 one. Above 4.0, only 5-star reviews move you up.
How many 5-star reviews cancel out one 1-star review?
(R − 1) ÷ (5 − R), rounded up, where R is your average. At 4.5 that is 7, at 4.7 it is 13 and at 4.9 it is 39. Your review count does not change the answer; it changes how much the 1-star review moved you in the first place.
How many 5-star reviews do I need to get a 4.5 rating on Google?
It depends on your current rating and how many reviews you have. A business at 4.2 with 120 reviews needs 55 more 5-star reviews in a row before Google shows 4.5. Enter your own numbers in the calculator above.
How is the number calculated?
Your total stars are your rating multiplied by your number of reviews. Each new 5-star review adds 5 stars and one review. Google rounds the average to one decimal (it shows 4.5 from 4.45), so the calculator finds the smallest number of 5-star reviews that makes Google show your target.
How many 1-star reviews would lower my rating?
It depends on your rating and review count. A business at 4.6 with 80 reviews is shown as 4.5 after 2 one-star reviews. The fewer reviews you have, the faster one bad review moves your average.
Can I reach a 5.0 rating?
Google shows 5.0 once your average reaches 4.95, so yes: enough 5-star reviews will get you there even with a few lower ones. An exact 5.00 average needs every review to be 5 stars.
Is the result exact?
It is a close guide. Google shows your rating rounded to one decimal, and the rating you enter is already rounded, so your true average may sit slightly above or below it.
Is this Google review calculator free?
Yes. No sign-up, no email and no limit. The arithmetic runs in your browser, so the numbers you type are not sent anywhere.
Does replying to reviews help my rating?
Replying does not change your average directly. Google says replies show you value feedback and can help your business stand out; more reviews and positive ratings are what Google says can help local ranking.
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