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Understanding results

What is a good TLS score?

Seven weighted categories, a penalty curve that cares about proportion as much as count, and a list of things the number deliberately ignores.

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The score compresses a lot of observations into one number between 0 and 100. It is built to help you triage, not to express a probability that you are secure. Treat a drop as a prompt to read the findings.

The seven categories

CategoryWeightWhat moves it
Certificate Health30%Expired, revoked, or near-expiry certificates being served; revoked OCSP responses
Confidentiality and Agility20%Forward secrecy gaps, RSA-only hosts, DNSSEC zone enumeration
Protocols15%SSLv3, TLS 1.0, TLS 1.1, certain OCSP stapling failures
Ciphers15%Flagged cipher families on assessed hosts
Web Hardening10%HTTP redirect gaps, missing HSTS, browser security headers
Reliability5%Selected connection failures, missing or broken DNSSEC, signature expiry risk
Future Readiness5%TLS 1.3, elliptic-curve certificate, and post-quantum coverage

Bands: Good at 80 and up, Fair 60 to 79, Poor 40 to 59, Critical below 40. These are SSLBoard’s bands.

Certificate Health being nearly a third of the score is intentional. An expired certificate is the one finding that is already breaking things for real users.

Why the same finding costs different amounts

The score is not a count of findings, and this is the part worth understanding.

Each category starts at 100. Every applicable issue multiplies down the category’s remaining score, using a rule-specific multiplier raised to an exposure amount. For most rules:

exposure = log2(affected + 1) + 3 × affected / eligible

Two things fall out of that shape:

  • The first bad endpoint hurts most. The logarithmic term means going from 1 to 2 affected costs more than going from 50 to 51.
  • Proportion matters as much as count. The affected / eligible term means one bad host out of two is punished far harder than one bad host out of two hundred. A half-finished rollout looks worse than a single stray box, which is correct.

Reliability rules normalize the logarithmic part by log2(eligible + 1) where an eligible count exists. The overall score is the weighted sum of the category scores.

Future Readiness works differently: it combines coverage rather than penalties. TLS 1.3 is half the category, elliptic-curve certificates a quarter, post-quantum readiness a quarter. Components with no eligible observations drop out and the rest are renormalized.

What the number ignores

Plenty of the report does not touch the score at all:

Missing observations are also not automatic failures. A category with no applicable penalties stays at 100, and Future Readiness defaults to 100 when it has no eligible components.

So a high score on a domain with heavy connection errors mostly measures how little was measured. Check coverage before you quote the number to anyone.

Comparing two reports

Compare findings and affected endpoints first, the number second. New discovery data, changed DNS answers, different eligible counts, and scoring changes can all move the score while your servers sit untouched.

The real proof a fix worked is the affected endpoint no longer showing the problem in a fresh report. See fixing and retesting.

Questions people ask

What is a good TLS score?

SSLBoard labels 80 and above Good, 60 to 79 Fair, 40 to 59 Poor, and below 40 Critical. These are SSLBoard's own bands, not an industry standard, and the findings matter more than the band.

Why did one expired certificate cost me so many points?

Certificate Health carries the heaviest weight at 30 percent, and the penalty scales with both how many endpoints are affected and what share of eligible endpoints that is. One expired certificate on a domain with two endpoints costs far more than one on a domain with two hundred.

Do email findings affect the TLS score?

No. Email security results, CAA policy rows, and adjacent-domain relationships are reported but do not currently feed the numeric TLS score.

My score changed but I did not touch anything. Why?

Discovery can return a different set of names, DNS can answer differently, and the eligible population a penalty is measured against can shift. Compare the findings and affected endpoints rather than the number alone.

Last verified Sep 18, 2026

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