The short answer. A carbon credit rating is an independent opinion on how likely a credit, or the project behind it, is to deliver the tonne it claims. BeZero Carbon rates credits and Sylvera rates projects, both on letter scales from AAA to D. A rating is a grade against defined criteria, not a percentile ranking, and neither agency builds co-benefits into the rating itself. It is one part of due diligence, alongside the methodology, the measurement, the verification and how the carbon is protected.
Last reviewed September 2026. Rating scales and methods change: check the agency’s current definitions.
What a rating is, and what it is not
- It is an opinion. An informed, independent view of the risk that a credit does not represent a real tonne, based on the agency’s own analysis.
- It is not verification. Verification is an accredited or registry-approved check that reported results meet the rules. A rating sits on top of that.
- It is not a ranking. A letter grade describes a level of likelihood, not a position in a league table.
- It can change. Ratings are monitored and can be revised as new information comes in.
BeZero Carbon ratings
BeZero rates credits on an eight-point scale that expresses its current opinion on the likelihood that a credit achieves a tonne of carbon dioxide equivalent avoided or removed:
| Rating | Likelihood the credit delivers its tonne |
|---|---|
| AAA | Highest |
| AA | Very high |
| A | High |
| BBB | Moderate |
| BB | Moderately low |
| B | Low |
| C | Very low |
| D | Lowest |
BeZero gives ex post ratings to credits that have been issued and ex ante ratings to projects before they issue, and monitors all ratings continuously. The rating focuses on carbon delivery.
Sylvera ratings
Sylvera rates projects from AAA to D, assessing the likelihood that the credits a project has issued have delivered on their claims. Its ratings rest on three pillars: carbon accounting, additionality, including the risk of over-crediting, and permanence. A strong score on one pillar cannot make up for a weak score on another. Co-benefits are scored separately and are not part of the rating.
Ratings, labels and verification
Three different things are often confused:
- Verification checks a project’s reported results for a period against its methodology and registry rules. It is done by an independent verifier. More in how carbon credits are verified.
- A quality label, such as the ICVCM’s Core Carbon Principles label, shows that both the crediting programme and the type of credit have been approved against a set of principles. The ICVCM publishes which programmes and methodologies are approved.
- A rating is an independent opinion on how likely a particular credit or project is to deliver its tonne.
How to use a rating in due diligence
- Check what was rated. A credit, a project or a vintage, and which one.
- Check the date. And whether the rating is under review.
- Read the definition. Quote the letter grade and the agency’s own meaning for it, not a paraphrase or a ranking.
- Read the reasons. Where the report is available, see which risks pulled the rating down.
- Check the basics yourself. How the carbon was measured, how the error was deducted, who verified it, and what protects the tonne if the carbon is lost.
What ratings look for in soil carbon
For soil carbon, the questions that decide a rating are the same ones any careful buyer asks: whether the carbon was measured or modelled, how the uncertainty was handled, whether the farm’s own emissions were deducted, whether the change would have happened anyway, and how long the carbon is monitored and protected. How we answer each of them is set out in accuracy stated and removal and avoidance credits.
Questions we are asked about carbon credit ratings
What is a carbon credit rating?
An independent opinion, usually a letter grade, on how likely a carbon credit or project is to deliver the tonne of carbon dioxide equivalent it claims.
What does a BeZero AAA rating mean?
AAA is the top of BeZero’s eight-point scale and means, in BeZero’s opinion, the highest likelihood that the credit achieves a tonne of carbon dioxide equivalent avoided or removed. D is the lowest.
What is the difference between BeZero and Sylvera?
Both are independent rating agencies using AAA to D scales focused on whether credits deliver their tonnes. BeZero rates credits, and projects before issuance. Sylvera rates projects, built on carbon accounting, additionality and permanence. Their methods differ, so compare the reports rather than the letters alone.
Does a rating replace verification?
No. Verification is the independent check that reported results meet the rules. A rating is a separate opinion that can take the verification into account.
Is a highly rated credit guaranteed?
No. A rating is an opinion on likelihood at a point in time, and it can change. It reduces the uncertainty in a purchase but does not remove it.
Sources: BeZero Carbon, rating definition and scale and ratings approach; Sylvera, ratings framework (updated September 2025); ICVCM assessment status. All checked 14 September 2026.
Related: for buyers · removal and avoidance credits · how carbon credits are verified · the soil carbon glossary
