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Your star rating is often the first thing a customer sees — on Google, on Amazon, on TripAdvisor. A 4.8 looks very different from a 4.0, even though only a few reviews separate them. This free star rating calculator works out your average rating from your 1–5 star reviews, shows how your reviews are spread across the five levels, and tells you how many more 5-star reviews you need to reach the target you set. Type in your counts, and the numbers update as you type. It works for any 1–5 star system — Google, Amazon, TripAdvisor, or your own feedback forms — and your numbers never leave your browser.
How to use the calculator
- Enter your review counts. Type how many 5-star, 4-star, 3-star, 2-star, and 1-star reviews you have. Leave any level at 0 if you have none.
- Set your target rating. The default is 4.5 — change it to whatever you are aiming for, up to 5.
- Read your results. You will see your total reviews, your average rating, a bar for each star level, and how many more 5-star reviews you need to reach your target.
Worked example
Say a café has 10 five-star reviews, 5 four-star reviews, 2 three-star reviews, 1 two-star review, and 2 one-star reviews — 20 reviews in total. Here is how the calculator works it out, step by step.
First, it adds up the stars: 10 × 5 is 50, 5 × 4 is 20, 2 × 3 is 6, 1 × 2 is 2, and 2 × 1 is 2 — 80 stars in total. Then it divides by the number of reviews: 80 stars ÷ 20 reviews = 4.00. So the café's average rating is 4.00.
Now say the café wants to reach 4.5. Each new 5-star review adds 5 stars and one more review, so the calculator works out the smallest number that lifts the average to 4.5 — and the answer is 20 more 5-star reviews. Check it: (80 + 100) ÷ (20 + 20) = 180 ÷ 40 = 4.5. The distribution bars tell the same story at a glance: half the reviews are 5-star, a quarter are 4-star, and the rest are spread across 3, 2, and 1 star.
Why a few bad reviews hurt so much
A single 1-star review feels unfair when everything else is 5 stars — and the maths agrees that it hurts. With only a few reviews, one bad one drags the average down a long way: a business with four 5-star reviews sits at 5.00, but one 1-star review drops it to 4.20. A new business with two 5-star reviews drops to 3.67 with a single 1-star review. The same review barely matters once you have a hundred reviews, because each single review is only a tiny share of the total.
That is also why the average moves so slowly once you have many reviews. With 20 reviews averaging 4.00, a single new 5-star review only lifts you to about 4.05 — 85 stars ÷ 21 reviews. Getting from 4.00 to 4.50 takes 20 more 5-star reviews, as the example above shows. The fix is not to remove the bad reviews — it is to keep earning good ones, steadily, so the good reviews outweigh the bad.
So do not panic over one bad review, and do not chase a perfect 5.00 — once you have any review below 5 stars, a perfect average is out of reach. Focus on the next good review instead: every one of them nudges the average up, and the bars above show you exactly where you stand.
Frequently asked questions
How is the average rating worked out?
Add up all the stars — 5 for each 5-star review, 4 for each 4-star review, and so on — then divide by the total number of reviews. For example, 10 five-star reviews and 5 four-star reviews give (50 + 20) ÷ 15 = 4.67.
Why do a few bad reviews hurt so much?
Because each low review pulls the total down, and with only a few reviews each one counts for a lot. Once you have many reviews the average barely moves, so the cure is more good reviews over time — not removing the bad ones.
How many 5-star reviews do I need to reach my target?
Type in your counts and your target rating, and the calculator works out the smallest number of extra 5-star reviews that lifts your average to the target. If you are already at or above your target, it will say so.
Can I use this for any platform?
Yes — Google, Amazon, TripAdvisor, any 1–5 star system. The maths is the same wherever the stars come from.
Does it store my numbers?
No — everything runs in your browser. Nothing is sent or stored anywhere, and your numbers disappear when you close the page.