Enter your current review count and rating, set your target — get a full scenario breakdown showing exactly how many 5★, 4★ or 3★ reviews you need.
Amazon uses a weighted average — not a simple mean — where recent reviews and verified purchases carry more weight. The base formula is: New Rating = (Current Rating × Review Count + New Stars) ÷ (Count + 1). This calculator uses that formula to show you exactly how many reviews you need.
It depends entirely on your current count and rating. A product at 4.2★ with 50 reviews needs ~30 five-star reviews. The same target from 4.0★ with 200 reviews needs ~100. Use the calculator above.
Directly. A product with 4.5★ typically converts 2–3× better than the same product at 3.5★. Better conversion means Amazon's algorithm charges less per click and ranks your Sponsored Products higher at the same bid.
4.5★ and above — best-in-category, highest conversion. 4.0★–4.4★ — competitive, good CTR. 3.5★–3.9★ — below average. Below 3.5★ — Amazon may suppress the listing entirely.
1. Use the "Request a Review" button in Seller Central within 4–30 days of delivery. 2. Enrol in Amazon Vine for new ASINs. 3. Optimise your insert cards. 4. Improve product quality — a single 1★ can take 5–10 five-star reviews to neutralise.