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Google Review Calculator

Find out exactly how many 5-star Google reviews you need to reach any target rating - 4.5, 4.7, 4.8 or 4.9 - plus how long it will take at your current pace. Instant, accurate, 100% free.

  • Accurate math
  • Works for Yelp & Trustpilot
  • No email required
Live calculator
Google Review Math
Your Google rating today · out of 5★
Total reviews on your profile
5/mo
12550
5★ reviews needed
44
New rating
4.8★
Time at pace
~9 mo

To go from 4.2★ (20 reviews) to 4.8★, collect 44 new 5-star reviews - about 9 months at 5/month.

How it works

Four inputs. One honest answer.

The Google review calculator uses the exact average-rating formula Google displays on your Business Profile - no guesses, no fluff.

  1. 01
    Enter your current Google rating

    Look at your Google Business Profile - that visible star average (e.g. 4.2★) is your starting point.

  2. 02
    Add your total review count

    Also on your GBP, next to the stars. The bigger this number, the more new reviews you need to move the average.

  3. 03
    Pick a realistic target

    4.7★ is competitive locally, 4.8★ is excellent, 4.9★ is best-in-class. 5.0★ is mathematically impossible once you have any lower review.

  4. 04
    Set your monthly pace

    How many reviews you actually collect each month. The calculator turns the required 5-star count into a realistic timeline.

The math

The Google review formula, explained

Google's public star rating is a straight arithmetic mean of every review's 1–5 star value, rounded to one decimal. To calculate how many new 5-star reviews you need to hit a target, we solve for N (new reviews) in this equation:

(current_rating × current_count + N × 5) ÷ (current_count + N) = target_rating

Rearranged and solved for N:

N = ⌈(target × count − current × count) ÷ (5 − target)⌉

Because Google rounds to one decimal, this is the minimum count that guarantees the displayed rating hits your target. The calculator above does this in real time for any inputs.

Worked example
4.2★ (20 reviews) → 4.8★
  • •Numerator: 4.8 × 20 − 4.2 × 20 = 96 − 84 = 12
  • •Denominator: 5 − 4.8 = 0.2
  • •Result: N = 12 ÷ 0.2 = 60 new 5-star reviews
  • •Verify: (4.2 × 20 + 60 × 5) ÷ 80 = 384 ÷ 80 = 4.80★ ✓
At 5 new reviews/month, that's about a 12-month climb. Most local businesses accelerate this with a structured invitation flow - the compliant, FTC-safe kind.
Who it's for

Every business that lives or dies on the local pack

Local service businesses

Plumbers, dentists, lawyers, HVAC - anywhere the Google 3-pack drives calls. Reaching 4.7★+ typically doubles click-through on local search versus 4.0★.

Restaurants & hospitality

Rating threshold matters more than count above 100 reviews. A 4.5★ restaurant sees ~35% more reservation clicks than a 4.0★ competitor with the same review count.

E-commerce brands

Google Seller Ratings unlock star snippets in ads and Shopping when you have 100+ reviews at 3.5★ or higher. The calculator helps you time the qualification threshold.

Multi-location brands

Model each location independently. A single 3.9★ outlier can pull down your brand average - the calculator shows exactly what it takes to recover per site.

FAQ

Google Review Calculator - questions people ask

How is the Google star rating calculated?+
Google averages every review's star value (1–5) across your Business Profile and rounds to one decimal. A single 1-star review among 20 reviews drops a 5.0 to about 4.8. The more reviews you have, the more each new review moves the needle less.
How many 5-star Google reviews do I need to reach 4.8?+
It depends on your current rating and review count. To go from 4.2 with 20 reviews to 4.8, you need roughly 60 new 5-star reviews. Use the calculator above with your exact numbers - the formula is (target × current_count − current_rating × current_count) ÷ (5 − target).
Can I reach 5.0 stars on Google?+
Mathematically only if every review you have is 5-star and every new one is too. Most established businesses top out at 4.9 because a small share of customers always leave 4-star or lower. Aim for 4.8–4.9 as a realistic ceiling.
How long will it take to raise my Google rating?+
Depends on your monthly review velocity. Most local businesses collect 3–15 reviews per month organically. Divide the required 5-star review count by your monthly rate for a realistic timeline. The calculator does this automatically.
Does Google weight recent reviews more than older ones?+
Yes. Google's local ranking algorithm gives more weight to recent reviews (last 12 months) and reviews with photos or long text. The visible star rating is still a straight average, but ranking factors are recency-weighted.
Is this Google review calculator free?+
Yes. The Google Review Calculator is 100% free, requires no signup, and stores no data. It runs entirely in your browser.
Can this calculator work for Yelp, Trustpilot or Tripadvisor?+
The math is identical for any 5-star rating platform. Use the same inputs for Yelp, Trustpilot, Tripadvisor, Facebook, Amazon or any other 1–5 star system - the required review count will be accurate.

Need to actually get to that rating?

BGR Review delivers verified 5-star Google reviews from aged, geo-targeted accounts - drip-fed to protect your profile, with a 30-day replacement guarantee.

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