# BeZero or Calyx: how do carbon credit ratings differ?

Canonical: https://senseible.earth/answers/which-carbon-credit-rating-agency

Both now use the same eight-letter scale from AAA to D for the chance a credit delivers one tonne. BeZero rates carbon efficacy only and publishes headline ratings free. Calyx gives separate GHG, SDG and environmental and social risk ratings, by vintage. Neither rating is a verification or a registry approval.

## BeZero Carbon

- Rates the likelihood a credit achieves one tonne of CO2e avoided or removed. Co-benefits and fraud risk are outside the rating unless they affect that likelihood.
- Headline ratings on issued credits are public and free. Pre-issuance ratings stay private unless agreed.
- Payment does not depend on the grade; no MRV consulting, no trading and no advice on which credits to buy.
- Every rating is approved unanimously by a ratings committee.

## Calyx Global

- GHG rating on four risks aligned with the ICVCM Core Carbon Principles: additionality, over-crediting, permanence and overlapping claims.
- Separate SDG ratings on a +1 to +5 scale, and an environmental and social risk screen across 10 areas.
- Ratings by vintage, so a project's grade can change over time.
- Does not sell ratings to project developers and does not trade credits. Developers can ask to join the rating queue at no charge.

## Reading the two side by side

The letters match, but Calyx scores four ICVCM-aligned risks while BeZero gives one view of carbon efficacy, so the same letter can rest on different reasons. Compare the reasons behind a rating, not just the letter.

## Not covered here

Sylvera and MSCI also rate credits. Read their own methodology pages before comparing their grades with these two.

## What Senseible does here

A rating agency reads the project's evidence. Senseible keeps that evidence in order: the records behind each tonne and the verifier evidence pack an accredited verifier reviews.

- [What a rating letter means](https://senseible.earth/answers/carbon-credit-rating-scale-meaning)
- [Do you need a rating?](https://senseible.earth/answers/do-i-need-a-carbon-credit-rating)
- [Carbon removal for buyers](https://senseible.earth/carbon-removal/buyers)
- [What to check before buying](https://senseible.earth/answers/what-to-check-before-buying-carbon-credits)

Sources: [BeZero Carbon, The BeZero Carbon Rating definition and rating scale (21 December 2023)](https://bezerocarbon.com/insights/the-bezero-carbon-rating-definition-and-rating-scale), [BeZero Carbon, Independent carbon ratings (8 April 2024, editor's note October 2026)](https://bezerocarbon.com/insights/independent-carbon-ratings), [Calyx Global, Our approach: GHG, SDG and environmental and social risk ratings](https://calyxglobal.com/approach), [Calyx Global, A new GHG rating scale (21 January 2025)](https://calyxglobal.com/research-hub/ratings-approach/a-new-ghg-rating-scale/), [Calyx Global, Calyx Ratings: free tiered ratings and who pays](https://calyxglobal.com/calyx-carbon-credit-ratings)

Last reviewed 2026-11-02.