# Google Review Calculator: How Many Reviews You Need and What They're Worth

To raise your Google rating, you need k five-star reviews where k = current reviews × (target − current rating) ÷ (5 − target). A business with 40 reviews at 4.2 stars needs 40 five-star reviews to reach 4.6. What that's worth in revenue depends on how many more people contact you, which you should measure, not assume.

## Key takeaways

- 5-star reviews needed = n × (target − current) ÷ (5 − target), rounded up.
- The more reviews you already have, the more it takes to move the average. A 5.0 is unreachable once you have any lower review.
- Divide by your own review rate to see how many customers to ask.
- Research on reviews and revenue exists, but none of it measures trades businesses. Treat the revenue lift as your assumption and test it.
- Ask every customer. Google's policy bans selectively asking only happy customers and offering incentives for reviews.

## How many 5-star reviews do I need to raise my rating?

It depends on how many reviews you have now and how far you want to move. Each new 5-star review pulls the average up a little, and the pull gets weaker as your review count grows. The formula below gives the exact number, assuming every new review is 5 stars. In real life some won't be, so treat the result as the minimum.

**Formulas**

```
Five-star reviews needed k = n × (T − R) ÷ (5 − T)   ·   Customers to ask = k ÷ q   ·   Extra revenue = C × L × B × P
```

Where:
- n = reviews you have now
- R = current average rating
- T = target average rating (below 5.0)
- q = your review rate: share of customers asked who leave a review
- C = contacts per month from your Google Business Profile
- L = assumed lift in contacts at the target rating (your estimate)
- B = booking rate
- P = average ticket

1. **Look up your current reviews and rating.** Search your business name on Google or open your Business Profile.
2. **Find your review rate.** Count how many customers you asked last month and how many reviews came in. If you've never asked systematically, start asking and measure for a month.
3. **Pull your profile contacts.** Your Business Profile's Performance report shows calls, messages, bookings and website clicks. Add them up for a typical month.
4. **Pick a conservative lift and test it.** Enter a small lift, then compare your Performance report three months before and after your review push. Replace the assumption with what you measured.

> **Worked example**
>
> A plumbing company has 40 Google reviews averaging 4.2 stars and wants 4.6. It needs 40 × (4.6 − 4.2) ÷ (5 − 4.6) = **40 five-star reviews**, ending at 80 reviews.
>
> About 25% of the customers it asks leave a review, so it needs to ask 160 customers. At a few dozen jobs a week, that's a few months of asking after every job.
>
> Its profile brings 90 calls, messages and website clicks a month. The owner assumes a 5% lift at the higher rating: 4.5 more contacts a month. At a 50% booking rate and $400 ticket, that's 2.25 jobs and **$900 a month, or $10,800 a year**.
>
> The review count is math. The revenue is an estimate built on the owner's assumed lift, and the owner should check it against the Performance report.

## How many reviews does it take to reach 4.5 stars?

**Five-star reviews needed to reach 4.5 stars**

| Current rating | 20 reviews now | 50 reviews now | 100 reviews now | 200 reviews now |
| --- | --- | --- | --- | --- |
| 3.8 stars | 28 | 70 | 140 | 280 |
| 4.0 stars | 20 | 50 | 100 | 200 |
| 4.2 stars | 12 | 30 | 60 | 120 |
| 4.4 stars | 4 | 10 | 20 | 40 |

_Calculated with the formula above, assuming every new review is 5 stars. Real results take more, because not every new review will be 5 stars._

A shop with 20 reviews at 4.2 stars needs 12 five-star reviews to hit 4.5. A shop with 200 reviews at the same rating needs 120. That's why one bad review hurts a new business far more than an established one, and why steady asking after every job beats a one-time review push.

## Do Google reviews actually bring in more revenue?

Reviews affect both whether you show up and whether people pick you. On visibility, Google says local ranking is based on relevance, distance and prominence, and that prominence includes how many reviews you have: "More reviews and positive ratings can help your business's local ranking." On choice, surveys show homeowners read them. In BrightLocal's 2026 Local Consumer Review Survey of 1,002 US adults, 97% said they read reviews for local businesses, 68% said they'd only use a business with four stars or more, and 47% said they wouldn't use a business with fewer than 20 reviews. In a 2024 Clear Seas Research survey for ACHR News, 91% of 400 homeowners rated online reviews an important factor when choosing an HVAC contractor, and 56% said they'd likely look on Google.

Measured revenue effects are harder to find. The best-known study, by Michael Luca at Harvard Business School, found that a one-star increase in Yelp rating led to a 5–9% increase in revenue, but for independent restaurants in Seattle, not contractors. No comparable study covers trades businesses, so this calculator leaves the lift to you. Start with a small number and replace it with what your own Performance report shows.

> **Ask every customer, and never pay for reviews**
>
> Google's content policy bars businesses from selectively soliciting positive reviews, discouraging negative ones, or offering incentives such as payment, discounts or free services in exchange for a review.
>
> The FTC's rule on consumer reviews, announced August 14, 2024, prohibits fake reviews and incentives conditioned on a review expressing a particular sentiment, and lets the FTC seek civil penalties. Send the same request to every customer after every job.

## How to get more Google reviews without breaking the rules

1. **Ask at the right moment:** right after the job is done and the customer has seen the result, by text with a direct link to your review form.
2. **Make it one tap.** Use the review link from your Business Profile so customers don't have to search for you.
3. **Ask everyone.** Same message, every completed job. That's both the rule and the way to keep reviews recent.
4. **Reply to every review,** good and bad, in your own words. A calm, specific reply to a bad review is read by every future customer.
5. **Use a template that sounds like you.** See [Google review request templates](https://www.brix.so/templates/google-review-request-templates) and [how to ask for Google reviews](https://www.brix.so/learn/how-to-ask-for-google-reviews).

BRIX sends a review request to every customer after the job is done, so your rating and review count keep growing without anyone having to remember to ask.

- [Review requests](https://www.brix.so/features/reviews-reputation): Asks every customer for a Google review automatically after the job, without filtering who gets asked.
- [Sales automation](https://www.brix.so/features/sales-automation): Follows up every lead and open estimate automatically by text and email, and asks every customer for a review after the job.

## Frequently asked questions

### How many 5-star reviews do I need to get to 4.5 stars?

Multiply your current review count by (4.5 − your rating) and divide by 0.5. With 50 reviews at 4.2, you need 30 five-star reviews. The calculator above does this for any starting point and target.

### Can I get back to a 5.0 rating?

No. Once you have any review below 5 stars, your average can approach 5.0 but never reach it. Set a realistic target such as 4.7 or 4.8 and focus on keeping reviews recent.

### How much revenue does one more star bring?

The best-known study found a one-star increase on Yelp led to 5–9% more revenue for independent restaurants. There's no comparable study for trades businesses. Compare your Google Business Profile Performance report before and after a review push to measure your own effect.

### Do more Google reviews help local ranking?

Google says prominence is one of its three local ranking factors, and that how many reviews you have and your ratings feed into it. More reviews and positive ratings can help, alongside relevance and distance from the searcher.

### Can I offer a discount for leaving a Google review?

No. Google's policy prohibits offering incentives such as payment, discounts or free services in exchange for reviews. The FTC's rule also bars incentives conditioned on a review expressing a particular sentiment. Ask every customer the same way, with no reward attached.

### What share of customers leave a review when asked?

It varies widely with how and when you ask. A text with a direct link sent right after the job usually does better than a request days later. Measure your own rate: reviews received divided by customers asked, for one month.

## Related

- [How to Ask for Google Reviews](https://www.brix.so/learn/how-to-ask-for-google-reviews)
- [What Is a Google Business Profile?](https://www.brix.so/learn/google-business-profile)
- [What Is the Google Local Pack?](https://www.brix.so/learn/local-pack)
- [Google Review Request Templates (Text, Email and In Person)](https://www.brix.so/templates/google-review-request-templates)
- [Review Request Automation: More Google Reviews Without Remembering to Ask](https://www.brix.so/features/reviews-reputation)
- [Customer Lifetime Value Calculator](https://www.brix.so/tools/customer-lifetime-value-calculator)
- [Booking Rate and Close Rate Calculator](https://www.brix.so/tools/booking-rate-calculator)
- [Cost Per Lead Calculator (and Marketing ROI)](https://www.brix.so/tools/cost-per-lead-calculator)
- [What Are Google Local Services Ads?](https://www.brix.so/learn/google-local-services-ads)
- [Missed Call Revenue Calculator](https://www.brix.so/tools/missed-call-calculator)

## Sources

- [Google Business Profile Help, Tips to improve your local ranking on Google](https://support.google.com/business/answer/7091) (checked 2026-10-12)
- [BrightLocal, Local Consumer Review Survey 2026 (published Feb. 11, 2026; 1,002 US adults)](https://www.brightlocal.com/research/local-consumer-review-survey/) (checked 2026-10-12)
- [ACHR News, 91% of Homeowners Rely on Online Reviews Before Picking Contractors (Sept. 17, 2024; Clear Seas Research, 400 homeowners)](https://www.achrnews.com/articles/155206-91-of-homeowners-rely-on-online-reviews-before-picking-contractor) (checked 2026-10-12)
- [Luca, Reviews, Reputation, and Revenue: The Case of Yelp.com, Harvard Business School Working Paper 12-016](https://www.hbs.edu/ris/Publication%20Files/12-016_a7e4a5a2-03f9-490d-b093-8f951238dba2.pdf) (checked 2026-10-12)
- [Google Maps User Contributed Content Policy, Prohibited and restricted content](https://support.google.com/contributionpolicy/answer/7400114) (checked 2026-10-12)
- [FTC, Federal Trade Commission Announces Final Rule Banning Fake Reviews and Testimonials (Aug. 14, 2024)](https://www.ftc.gov/news-events/news/press-releases/2024/08/federal-trade-commission-announces-final-rule-banning-fake-reviews-testimonials) (checked 2026-10-12)

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Written by BRIX Editorial Team. Last updated 2026-10-12.
Canonical: https://www.brix.so/tools/review-revenue-calculator