A plumber in Leeds at 4.2 stars and a competitor two streets away at 4.8 offer the same service at roughly the same price. Which one gets the call? Most owners assume the higher number wins every time. The research gives a messier answer, and the details change what you should do next.
This guide sets out what the published evidence says, where it stops, and what a UK small business can do about its rating this month.
Does star rating affect sales at all?
The most cited study comes from the Spiegel Research Center at Northwestern University. Its researchers found that purchase likelihood typically peaks for ratings between 4.0 and 4.7, then declines as ratings get closer to 5.0. They also found that a product with five reviews had a purchase likelihood 270% higher than one with no reviews.
So the honest answer has two parts. Having reviews at all makes a very large difference. Once you have them, the rating works more like a threshold than a sliding scale.
Is 4.2 really worse than 4.8?
BrightLocal's 2026 Local Consumer Review Survey found that 68% of consumers will only use a business with four or more stars, up from 55% in 2025. It also found that 31% will only use a business rated 4.5 or higher, up from 17% the year before. A 4.2 clears the first bar and misses the second.
Picture the Google Maps results for "emergency electrician Bristol". You see six businesses, most between 4.6 and 4.9. At 4.2 you are not invisible, but you are the one that looks like it has a problem. Someone in a hurry scrolls past.
There is a caveat. BrightLocal surveyed 1,002 US adults, and what people say in a survey is not always what they do. UK search behaviour on Google tends to be similar, but treat the 31% as a direction, not a forecast for your own enquiries.
Why doesn't a perfect 5.0 always win?
People read a few four-star reviews as proof that the reviews are real. A 5.0 from 14 reviews, all three lines long and all posted in the same fortnight, invites suspicion. BrightLocal found just 10% of consumers say they will only use five-star businesses, so chasing perfection buys you very little.
How much does the number of reviews matter compared with the rating?
BrightLocal found that 47% of consumers won't use a business with fewer than 20 reviews. The Spiegel team found the extra benefit of each review shrinks quickly after the first five, which sounds like it contradicts BrightLocal. It doesn't. Five reviews get you taken seriously. Twenty gets you past the doubters.
Volume also protects the average. At 15 reviews, one angry one-star knocks a 4.8 down noticeably. At 150, the same review barely moves it. That alone is a good reason to keep a steady flow coming.
Do old reviews still count?
According to BrightLocal, 74% of consumers look for reviews written in the last three months, and 32% look for reviews from the last two weeks, up from 20% the year before. A café with a 4.8 from 200 reviews, the latest from last spring, looks like a business that may have changed hands or stopped caring.
The practical fix is rhythm, not a campaign. Ask every customer at the natural end point of the job: the receipt, the follow-up text after a boiler service, the email after a treatment.
Do replies to reviews change the outcome?
BrightLocal found 89% of consumers expect business owners to respond to reviews, and 80% say they are likely to use a business that responds to all of its reviews. The same survey found templated or generic replies make 50% of consumers unlikely to choose a business.
A reply to a two-star review is written for the next 100 readers, not the reviewer. Name the specific issue, say what changed, and offer a direct contact. "Sorry the Saturday delivery slot was missed. We have since added a second driver at weekends. Call the shop and ask for Sam if it happens again" does more than any five-star review. If complaints keep repeating, a proper process helps, and this guide to handling complaints with AI tools covers the triage side.
What are UK businesses allowed to do to raise their rating?
The Digital Markets, Competition and Consumers Act banned fake reviews from 6 April 2025. Law firm CMS explains that the banned practices include suppressing negative reviews and cherry-picking positive reviews for publication, and that the CMA can fine businesses up to 10% of annual global turnover without going to court. Incentivised reviews are allowed only when they are clearly labelled as incentivised and still reflect a genuine experience.
That rules out the old trick of sending a "how did we do?" survey and only pointing happy customers to Google. What stays legal is simple:
- Ask every customer, in the same way, at the same point in the journey.
- Use a short direct link to your Google review form, not a landing page that filters people.
- Reply to every review within a week.
- Fix the recurring cause. If three reviews mention slow callbacks, the answer is a callback process, not more review requests.
Should you show your star rating on your own website?
Many visitors land on a service page straight from a paid ad and never see your Maps listing. Bringing the rating and a few recent reviews onto the page closes that gap. This guide on adding reviews to your website covers widgets, schema and where to place them. If you want proof that it moves enquiries on your own site, test it rather than assume, using the approach in this guide to A/B testing for small businesses.
What should you do if you're stuck at 4.2?
Export or copy your last 30 reviews. Tag every review under four stars by cause: price, wait time, communication, quality, one staff member. In most small businesses, one or two causes account for most of the damage. A dental practice might find almost every three-star review mentions the phone line at lunchtime. That is a staffing fix, not a marketing one.
Then do the maths on your own numbers. At 60 reviews averaging 4.2, you would need 36 new five-star reviews in a row to reach 4.5, and more if any four-star reviews arrive along the way. That takes months of steady asking, not a weekend push. It is why the businesses with high ratings tend to be the ones with a habit, not a campaign.
The short version is that 4.2 versus 4.8 matters, but mostly because of the customers who set a 4.5 cut-off and the competitors sitting above you on the map. Get past 4.0, aim for the 4.5 bar, keep reviews recent, reply to every one, and stop worrying about a perfect 5.0.
Star Rating and Conversions — FAQ
Does star rating affect sales for a small business?
Yes, but not in a straight line. The Spiegel Research Center at Northwestern University found that purchase likelihood typically peaks for ratings between 4.0 and 4.7 stars, then falls as ratings get closer to a perfect 5.0. Separately, BrightLocal's 2026 Local Consumer Review Survey found that 68% of consumers will only use a business with four or more stars. Dropping below 4.0 hurts you most. Above that, how many reviews you have, how recent they are and how you reply to them often matter as much as the decimal point. A UK business sitting at 3.8 should focus on getting over 4.0 first.
Is a 4.2 rating bad compared with a 4.8?
A 4.2 is not a bad rating. It sits inside the 4.0 to 4.7 range where the Spiegel Research Center found purchase likelihood usually peaks. The risk is a specific group of customers. BrightLocal's 2026 survey found 31% of consumers say they will only use a business rated 4.5 stars or more, so a 4.2 rules you out with them before they read a single review. A 4.8 clears that bar. The gap matters most in competitive categories such as trades, dentists and restaurants, where a searcher sees several 4.6 to 4.9 businesses side by side on Google Maps.
Can a perfect 5.0 star rating put customers off?
It can. The Spiegel Research Center reported that purchase likelihood tends to decline as ratings approach 5.0, because a perfect score with no criticism can look too good to be true. BrightLocal's 2026 survey also found only 10% of consumers say they will only use five-star businesses, so a perfect score is not what most people demand. A 4.8 with a few honest four-star reviews and calm, specific owner replies usually reads as more believable than a flawless 5.0 from a small number of reviews.
How many Google reviews does a UK business need?
Google publishes no minimum, but customers have their own. BrightLocal's 2026 Local Consumer Review Survey found 47% of consumers won't use a business with fewer than 20 reviews, and 74% look for reviews written in the last three months. The Spiegel Research Center found purchase likelihood for a product with five reviews was 270% higher than for one with none, with the benefit of each additional review shrinking quickly after the first five. A sensible target is at least 20 reviews, then a steady flow of new ones each month rather than one big push.
Is it legal to only ask happy customers for reviews in the UK?
Be careful here. Since 6 April 2025, the Digital Markets, Competition and Consumers Act has banned fake reviews in the UK, and law firm CMS notes that the banned practices include suppressing negative reviews and cherry-picking positive ones for publication. Filtering unhappy customers away from Google before they can review carries real risk, and the CMA can fine businesses up to 10% of annual global turnover. The safer approach is to ask every customer the same way, label any incentivised review clearly, and deal with complaints directly.
