---
title: "Amazon Review Velocity Calculator | Rating Forecast & 5-Star Math - Flapen"
canonical_url: "https://flapen.com/tools/review-velocity-calculator"
last_updated: "2026-07-18T11:20:41.255Z"
meta:
  description: "Free review calculator for Amazon sellers — project your review growth, see how many 5-star reviews lift your rating (and how many 1-stars hurt it), and find the pace to catch a competitor."
  "og:description": "Free review calculator for Amazon sellers — project your review growth, see how many 5-star reviews lift your rating (and how many 1-stars hurt it), and find the pace to catch a competitor."
  "og:title": "Amazon Review Velocity Calculator | Rating Forecast & 5-Star Math - Flapen"
---

# **Review Velocity Calculator**

Review growth, rating forecast, and competitor catch-up

**Review goal****month 19** Month 14 if sales take off, month 24 if they stay flat.**Rating goal****never** At a 4.38★ incoming average you lose your 4.5★ display around month 18. Cut your 1★ share to 3% and you'd settle at 4.5★ instead.**Catch rival****+102/mo** That's about 3,400 units/mo at your 3% review rate. At your current pace, parity waits until ≈ month 88.1,0002,0003,000target 5001,971856611today6 mo1 yr18 mo2 yrs30 mo3 yrs**Show competitor (1,374 reviews, +30/mo)**### **What to do next**1. Cut your 1★ share 6% → 3% (fix the top complaint): you'd settle at 4.5★ instead of 4.4★. 2. Lift your review rate 3% → 4% (Request-a-Review, inserts): 500 reviews by month 15 instead of 19. 3. Catching them in 1 year is a sales target: +102 reviews/mo ≈ 3,400 units/mo. ## **How review velocity works — and what really moves your rating**- **Review velocity** Your velocity is simply monthly orders × review rate: 300 orders at a 3% review rate adds about 9 reviews a month. Because orders usually grow, velocity compounds — the pace you have today understates where you'll be in a year. - **The review rate** Between 1% and 3% of Amazon buyers leave a review; great inserts, the Request-a-Review button, and Vine push toward the top of that range. Doubling the rate doubles your velocity without selling one extra unit — it's the cheapest lever you have. - **The 5-star math** Your displayed rating is a weighted average, so every milestone has a price in reviews: at 100 reviews and 4.0★, it takes 82 five-star reviews to display 4.5★. The price scales with your base — at 1,000 reviews it's 819. Rating inertia grows as you grow. - **The 1-star damage** The math is brutally asymmetric: the climb scales with your entire review base, the fall doesn't. The same 100-review listing that needs 82 five-stars to climb to 4.5★ loses that display after just 2 one-star reviews. Your cushion — how many bad reviews you can absorb — is a number worth knowing before a bad batch ships. - **Your rating's ceiling** Your rating converges to the average star of your incoming reviews. If new reviews average 4.4★, no amount of volume ever displays 4.5★ — the target is mathematically unreachable until the product itself improves. Fix the mix before scaling the velocity. - **Catching a competitor** Catch-up is gap ÷ closing speed: 1,000 reviews of gap closes in 20 months at +50/mo net. If your velocity is below theirs, the gap only widens — the calculator flips to the velocity you'd need, and since velocity is orders × rate, that's really a sales-volume target. ## **Review velocity, rating math & catching up**