What does an A or BBB carbon credit rating actually mean?

On BeZero's scale, A means a high likelihood the credit achieves one tonne of CO2e avoided or removed, and BBB means a moderate likelihood. The scale runs AAA, AA, A, BBB, BB, B, C, D. Calyx uses the same eight letters for its GHG rating. A rating is an opinion on risk, not a guarantee.

BeZero's eight notches

• AAA: highest likelihood of achieving one tonne.
• AA: very high. A: high.
• BBB: moderate. BB: moderately low.
• B: low. C: very low. D: lowest.

What the letter does not cover

• Co-benefits such as biodiversity, jobs or SDG claims, unless they affect whether the tonne is real.
• Business risks such as fraud, default or political interference, except where they bear on carbon efficacy.
• Whether the credit suits your claim. Check removal versus reduction separately.

Calyx letters are close, not equal

Calyx moved its GHG rating to the same eight-point scale in January 2025. Its old A+ became AAA or AA, and its old B became BBB or BB, depending on how the project scored on additionality, over-crediting, permanence and overlapping claims.

How to use a rating

Treat it as one input alongside the registry record, the methodology version and any ICVCM CCP label. Ratings can change: BeZero monitors its ratings continuously and Calyx rates by vintage.

What Senseible does here

Senseible's buyer view shows the record a rating rests on: the field, kiln and lab test behind a carbon removal tonne, its permanence and who signed off.

• BeZero and Calyx compared
• Do you need a rating?
• ICVCM Core Carbon Principles
• Carbon removal for buyers

Sources: BeZero Carbon, The BeZero Carbon Rating definition and rating scale (21 December 2023), BeZero Carbon, Ratings approach: committee approval and continuous monitoring, Calyx Global, A new GHG rating scale (21 January 2025)

Last reviewed 2026-11-02.