Free tool
Star rating calculator
Enter your current rating, how many reviews you have and the rating you want. The calculator tells you exactly how many new five-star reviews it takes to get there — and how much a single one-star review would cost you.
Five-star reviews needed
53
To move from 4.2 to 4.5 across 87 existing reviews.
If they average four stars
Not possible
Four-star reviews can never lift you to 4.5 — you need reviews above your target.
One new one-star review would take you to 4.16. The more reviews you hold, the less any single bad one moves the average — volume is your insurance.
Google displays the average rounded to one decimal place, so hitting 4.5 only needs an average of 4.45 or higher.
How the maths works
Your displayed rating is a simple average: total stars divided by total reviews. To reach a target, you need enough new reviews above that target to drag the average up. The formula the calculator uses is x = (target × count − current × count) ÷ (new rating − target), rounded up to the next whole review.
Two things follow from that. First, reviews below your target can never lift you — four-star reviews will not take you to 4.5. Second, the bigger your existing review count, the more new reviews each decimal point costs, which is why it pays to build the habit of asking early.
Show the rating you worked for
Embed your live star rating and reviews on your website free — updates automatically as new reviews arrive.
The fastest way to add reviews
- Create a one-tap Google review link and send it by SMS the same day as the job.
- Print a scan-to-review card for the counter, the invoice or the delivery box.
- Reply to every review with the review response generator — replying reliably earns more reviews.
- Understand what the number does for you in the psychology of star ratings.
Frequently asked questions
How many 5-star reviews do I need to raise my rating?+
It depends on how many reviews you already have. Moving from 4.2 to 4.5 with 87 reviews takes roughly 53 new five-star reviews, but the same jump with only 20 reviews takes about 12. Enter your numbers above and the calculator works out the exact figure instantly.
How is a Google star rating calculated?+
Google averages every star rating on your Business Profile and displays the result rounded to one decimal place. There is no weighting for recency in the displayed number, so older reviews count exactly the same as today's — which is why volume matters so much.
How much does one 1-star review hurt?+
The fewer reviews you have, the more it hurts. A single one-star review drops a 4.8 average with 10 reviews to 4.45, but the same review only moves a 4.8 with 300 reviews to 4.79. Building volume is the cheapest insurance against a bad day.
Why is 4.7 better than a perfect 5.0?+
Research into ratings consistently shows purchase intent peaks between about 4.2 and 4.7. A flawless 5.0 with a handful of reviews reads as suspicious, while a 4.7 across hundreds of reviews reads as real. Chase volume and honesty rather than perfection.
Can I remove a bad review to fix my average?+
Only if it breaches the platform's content policies — spam, offensive content, conflicts of interest or a reviewer who was never a customer. You can report it, but the reliable route to a better average is replying well and out-earning it with new reviews.
What is a good Google rating for a local business?+
Anything at 4.5 or above puts you comfortably in the consideration set for most local searches, and above 4.0 is generally acceptable. Below 4.0 you'll see click-through drop noticeably, particularly when competitors on the same map pack sit higher.