Buying a carbon offset means paying for one tonne of CO₂ equivalent to be reduced or removed somewhere else, and having the credit retired so nobody else can use it. This guide covers the steps, what to check before you pay, and what prices to expect. It is part of our buying guides; for the bigger picture, start with the guide to buying carbon credits.
Should you offset at all?
Offsetting works best as the last step, not the first. The Oxford Offsetting Principles start with cutting your own emissions and treat credits as a complement for what remainsSource 1. VCMI says credits must be used in addition to deep decarbonisation, not to delay or displace itSource 2.
That still leaves a role for credits. Some emissions are hard to cut quickly, and credits can also be bought and retired as a contribution to climate action, without being used as an offset at allSource 1. Our page on carbon credits vs carbon offsets explains the difference.
How to buy carbon offsets, step by step
Step 1: Cut what you can first
Reduce your own emissions before you offset, and use credits only for what is left.
Step 2: Estimate the tonnes to cover
Work out the emissions you want to offset in tonnes of CO₂ equivalent. One credit covers one tonne.
Step 3: Choose the type of credit
Decide between avoidance and removal credits, and pick a project type and standard.
Step 4: Choose a seller
Pick a retailer, marketplace or broker that names the project, standard and registry before you pay.
Step 5: Check the credits
Ask for the serial numbers and registry, and check the project’s methodology, including whether it can carry the CCP label.
Step 6: Confirm the retirement
Look up the retirement in the public registry and check that the quantity, serial numbers and your name match.
One credit represents one tonne of CO₂ equivalent: Verra defines its units this waySource 3, and Gold Standard uses the same unitSource 4. So 3 tonnes of emissions need 3 retired credits. For a flight, our flight emissions calculator gives you the tonnes per passenger.
Avoidance or removal credits?
Avoidance credits pay for emissions that would otherwise have happened, such as protecting a forest or replacing a polluting stove. Removal credits pay for CO₂ taken out of the atmosphere and stored. Most credits sold today are avoidance creditsSource 1.
The Oxford Principles recommend shifting your mix toward removals over time, and toward storage with a low risk of reversalSource 1. Removals cost more, so many buyers mix the two. Our page on removal vs avoidance credits covers the trade-offs.
Where to buy carbon offsets
You can buy offsets from several kinds of seller. Retailers suit small, one-off purchases; marketplaces let you pick the project; brokers and exchanges mostly serve organisations buying larger volumes. The table below is built from the providers we track, using what each provider’s own pages say.
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| Type | How you buy | Serves (from our records) | Examples |
|---|---|---|---|
| Retailer / offset shop | Sells credits it has already chosen, often at a fixed price per tonne, and retires them for you | Individuals, Small businesses, Companies | BuyCarbonOffsets.org *, Cool Effect, Ecologi |
| Marketplace | Lists credits from many projects or sellers, so you choose the project | Individuals, Small businesses, Companies | Carbonmark, Gold Standard Marketplace, Supercritical |
| Broker | Sources and negotiates credits for an organisation, usually through a sales conversation | Small businesses, Companies | Climate Impact Partners, Patch |
| Exchange | Trading platform with standard contracts for organisations and traders | Companies | Climate Impact X (CIX) |
| Project developer | Runs or finances its own projects and takes money for them directly | Individuals, Small businesses, Companies | atmosfair, myclimate |
* Same operator · DisclosureWho each type serves and the examples come from the providers' own pages. Examples are listed alphabetically, not ranked.As of Oct 2026
Whichever you choose, the checks in the next section are the same. A seller that won’t name the project, the standard and the registry before you pay doesn’t give you enough to check.
What to check before you pay
Five checks for any offset
- Serial numbers and registry. You should be able to look the credits up in the standard’s public registry.
- Retirement with your name. On the Verra Registry, a retirement record shows the serial numbers and, if the account holder chooses, the retirement reason and beneficial ownerSource 5. Ask for your name to be shown.
- The standard. Credits should come from a recognised standard such as Verra or Gold Standard, each with its own public registry.
- The methodology and CCP label. The ICVCM’s 10 Core Carbon Principles set a quality threshold, and credits that meet it can carry the CCP labelSource 6.
- When the reduction happens. Some offsets fund reductions that will happen years from now. US guidance says sellers should clearly disclose if the reductions won’t occur for two years or longerSource 10.
The CCP label is a useful filter because it is applied to whole methodologies. In August 2024, for example, the ICVCM decided that credits from eight current renewable energy methodologies would not receive itSource 7.
Quality matters because not every credit delivers what it claims. One review of studies covering almost a billion tonnes of credits estimated that less than 16% were real emission reductionsSource 9. Do carbon offsets work? sets out the evidence and how standards have responded.
How much do carbon offsets cost?
Prices vary widely by project type. Ecosystem Marketplace’s survey of 2024 deals found that removal credits sold for an average of $19.50 per tonne, against $4.05 for reduction creditsSource 8. In total it recorded $535 million of transactions for 84 million tonnes of CO₂eSource 8.
These are averages of deals reported to the survey, so they are a guide, not a quote. Retail prices for small purchases are usually set by each seller and include its own costs, so compare the price per tonne and what you get for it: the project, the standard and the retirement record.
Red flags when buying offsets
Walk away if you see these
- Offsets sold as an investment. The FCA warns that people who bought carbon credits as an investment have reported they can’t sell themSource 11. Offsets you use are retired and can’t be resoldSource 4.
- No serial numbers or registry. Without them you can’t confirm the tonnes exist or that they weren’t sold twice.
- Vague projects. “Supports climate projects” with no named project, standard or methodology.
- Credits counted twice. US guidance says offset sellers should use reliable methods to make sure they don’t sell the same reduction more than onceSource 10.
Our guide to carbon credit scams covers the common patterns and where to report them.
What to say once you have offset
Keep your claim to what you can show. US guidance treats it as deceptive to claim that an offset represents a reduction that the law already requiredSource 10, and the wording of claims is where many buyers go wrong.
Claims: say what you did
The Oxford Principles note that “carbon neutral” has come to be read as a less rigorous, interim claim, often made well before net zeroSource 1. A factual statement is clearer: how many tonnes you retired, from which project, with a link to the registry record.
If you are buying for yourself, our guide to buying carbon credits as an individual covers flights and everyday emissions. For a business, see the guides for small businesses and companies, and compare sellers on where to buy carbon credits. To check your credits after you buy, follow how to verify carbon credits.