The maths behind it
Your average is the total of all star ratings divided by the number of reviews. Each new review pulls the average towards its own star value, but the more reviews you already have, the less each new one moves it.
Reviews needed = current reviews × (target − current rating) ÷ (new review rating − target)
The result is rounded up. If new reviews average the same as or below your target, the target cannot be reached with those reviews alone, and the calculator says so.
Example
You have 38 reviews averaging 4.2 and want 4.6. With new 5-star reviews: 38 × (4.6 − 4.2) ÷ (5 − 4.6) = 38. You need 38 more five-star reviews. If new reviews average 4.8 instead, you need 76.
Displayed vs exact rating
Google shows ratings to one decimal place, so a true average of 4.55 may display as 4.6. The calculator works on the exact figure you enter, so the displayed rating may tick over slightly earlier.
Getting reviews the right way
- Ask everyone, not only happy customers. Google’s policies prohibit “review gating” (filtering who is asked) and offering incentives for reviews.
- Make it easy. Send your direct review link by text or email soon after the job.
- Reply to every review, especially critical ones. A calm, specific reply often matters more to prospects than the rating itself.
- Never buy reviews or post fake ones. Google removes them and can restrict or suspend the profile.
Our guide to getting more Google reviews without breaking the rules has templates and timing tips.
Rating isn’t everything
Review count, recency and what reviews say also influence both customers and local rankings. A 4.7 rating from 150 recent reviews usually beats a 5.0 from six. Check your other local signals with the Local SEO Readiness Checker.