Plain-English answers about carbon credits, certification standards, methodologies and how Carbon Unity fits in. If you do not see your question here, please get in touch.
A carbon credit is how project developers monetise real climate impact. Each credit represents a measurable unit of carbon removed or reduced, which can then be sold to buyers looking to offset their emissions.
A carbon standard is an organisation that sets the rules a project must follow before it can issue credits. Standards such as Verra, Gold Standard, Puro.earth and Isometric each have their own eligibility criteria, approved methodologies and verification processes. Meeting those criteria is what separates a credible carbon project from one that cannot issue credits.
A methodology is the framework project developers follow to assess and quantify their carbon impact. It sets out precisely how emissions reductions or removals should be measured, monitored and reported under a given standard. Different standards use different methodologies, and the choice of methodology has a direct bearing on how many credits a project can generate.
Eligibility tells you whether your project meets the criteria to issue credits under a given standard. Quantification estimates how many credits it could generate. These are related but distinct: a project can have genuine climate impact and still fall short of a standard's eligibility criteria, which would prevent it from issuing credits regardless of how real the impact is.
There is no single figure, because it depends on how much carbon the biochar holds and how much of it is expected to stay stable. Under Verra VM0044 v1.2, for example, the main drivers are the biochar's organic carbon content, a permanence factor set by production temperature (0.65 to 0.89), and the emissions from producing, transporting and applying it. The calculator works this through for your project.
A removal credit represents carbon taken out of the atmosphere and stored, while an emission reduction credit represents emissions avoided compared with what would otherwise have happened. Biochar under Verra VM0044 v1.2 and tree planting under VM0047 v1.1 generate removals. Clean cooking under Gold Standard RECH v5.0 or Verra VM0050 v1.0 generates reductions. Net zero guidance increasingly points to removals for residual emissions.
Source: Oxford Offsetting Principles (2024) · Start the eligibility check →
Six standards accept biochar projects: Verra (VM0044 v1.2), Puro.earth (Biochar Edition 2025 v2), Isometric (Biochar v1.3), Carbon Standards International (Global Biochar C-Sink v3.3 and Global Artisan C-Sink v2.1A), Rainbow (BiCRS V1.1, plus open-kiln and closed-kiln V1.0) and the Climate Action Reserve (Biochar Protocol V1.0). The Climate Action Reserve only covers projects in the United States and Canada. Gold Standard has no biochar methodology. Which ones fit depends on your location, scale and technology.
Verra VM0050 v1.0 covers most efficient and fuel-switch cookstoves, while Gold Standard MECD v2.0 only covers devices whose energy or fuel use is measured on every unit. Under VM0050, fuel savings can come from Kitchen Performance Tests or default values, and emission reductions are multiplied by 0.95. MECD requires continuous tracking of 100% of devices, for example smart-metered electric cookers or pay-as-you-go LPG stoves.
Source: Gold Standard MECD v2.0 · Check your clean cooking project →
The choice depends on how fuel use is measured and how big the project is. MECD v2.0 is for stoves with metered energy or fuel use on every device. RECH v5.0 covers non-metered improved biomass stoves, heat retention cookers and solar cookers. SMEC v4.0 is a simplified route for household projects of up to 10,000 tCO2e a year, where the baseline is wood or charcoal on a traditional stove.
Source: Gold Standard RECH v5.0 · Check your clean cooking project → · Clean cooking methodologies explained
Verra's ARR methodology is VM0047 Afforestation, Reforestation and Revegetation, currently version 1.1 (May 2025). It covers tree planting, seeding and assisted natural regeneration. Projects use either an area-based approach, which measures sample plots across the project area, or a census-based approach, which counts and measures individual trees.
Source: Verra VM0047 v1.1 · Check your ARR project →
Carbon Unity is a free tool for project developers to assess and quantify their carbon projects before starting the formal feasibility process. It tells you which standards your project may be eligible for, and gives you an early estimate of how many credits it could generate. Think of it as a way to stress-test your project against recognised frameworks before you commit time and money to a consultant.
Yes. The eligibility check is free for biochar, clean cooking and ARR projects, and quantification is free for biochar and clean cooking during the beta. Project data stays private to your account and is never sold or shared for advertising. If you use the tools without an account, your answers are kept in your browser for that session only.
Source: Privacy policy · Start the eligibility check →
Verra (VCS), Gold Standard, Puro.earth, Isometric, Carbon Standards International (Global Artisan C-Sink and Global Biochar C-Sink), Rainbow and Climate Action Reserve. Which ones apply depends on your project type and location.
Carbon Unity covers biochar, clean cooking and afforestation, reforestation and revegetation (ARR). Eligibility is live for all three. Quantification is live for biochar and clean cooking, and ARR quantification is in private preview.
You can start with whatever information you have. The more detail you provide, the more useful your results will be, but you do not need everything figured out before you get started.
Each standard has different eligibility criteria and quantification techniques, and the right choice depends on the specifics of your project. Carbon Unity will suggest the most suitable option based on the information you provide, but committing to a pathway without consulting a carbon expert first is not something we would recommend.
No. Results are indicative: they point you toward the most suitable standard and give a sense of your potential credit volume. They should not be treated as certification advice. Always consult a qualified carbon expert before making any decisions.
The forecasts are indicative and should not be used as investment advice. They are built on calculation frameworks from official methodologies, so the approach is grounded in recognised practice. Formal third-party verification is required before any credits can actually be issued.
Yes. A tool like Carbon Unity can help you arrive at the conversation with a better foundation, but it is not a substitute for tailored expert advice. If you would like to speak to someone, get in touch and we can point you in the right direction.
The eligibility assessment takes about five minutes. Suggestive only - please review results with a carbon expert before acting.