Free Trustpilot TrustScore Calculator (Bayesian formula)

Trustpilot uses Bayesian smoothing. Every business effectively starts with 9 imaginary reviews at 3.5 stars. As you collect real reviews, those imaginary ones get washed out, but for low-volume profiles they pull your average toward 3.5. A profile with 50 reviews averaging 4.8 stars typically shows a TrustScore around 4.5-4.6.

Yes. Reviews from the last 12 months get full weight. Reviews 12-24 months old: ~70% weight. 24-36 months: ~45%. 36+: ~30%. This calculator approximates the Bayesian component but does not model time decay (it assumes all reviews are recent). For older review bases, your real TrustScore may be slightly lower than this tool shows.

A simple average treats every review equally and starts from a clean slate. The Bayesian average smooths toward the platform mean (3.5/5) for low-volume profiles. As volume grows, the two converge. At 1000+ reviews, they're typically within 0.05 points. At under 100 reviews, the difference can be 0.3-0.5 points.

Volume is the highest-leverage move. Going from 100 to 500 reviews of the same average rating raises your TrustScore by ~0.15 points (Bayesian dilution). Active collection beats passive collection by 5-8x in volume. See our <a href="/blog/how-to-get-more-trustpilot-reviews-on-shopify">9-tactic Trustpilot collection playbook</a> for the operational details.