Offsetting a carbon footprint sounds more complicated than it is. In practice, it comes down to three steps: measuring your emissions, buying credits that match that amount, and making sure those credits are permanently retired. Here’s what each step actually involves.
Step 1: Measure Your Footprint
Before you can offset anything, you need a number. A footprint calculation converts everyday activity — driving, flying, home energy use, purchases — into CO2-equivalent (CO2e), using emission factors published by bodies like the UK’s DEFRA and the US EPA. Where gases other than CO2 are involved, such as methane or nitrous oxide, they’re converted using Global Warming Potential values from the IPCC’s Sixth Assessment Report, so everything ends up in one comparable unit.
Coffset’s carbon footprint calculator runs on DEFRA 2024 factors and current IPCC GWP values, and takes a few minutes to produce a footprint in kilograms of CO2e — whether you’re calculating a single flight, a household’s annual footprint, or a business’s Scope 1–3 emissions.
Step 2: Buy Matching Credits
One carbon credit represents one tonne of CO2e that’s been reduced, avoided, or removed somewhere else — a forest kept standing, a landfill’s methane captured, a renewable energy project displacing fossil fuels. Once you know your footprint in kilograms or tonnes, you buy the equivalent number of credits.
The quality of the credit matters as much as the quantity. Credible credits come from projects independently certified by standards like Verra or Gold Standard, which verify that the reduction is real, additional (it wouldn’t have happened without the offset revenue), and not being claimed by more than one buyer. You can buy carbon credits directly through Coffset, sourced from a portfolio of Verra- and Gold Standard-certified projects.
Step 3: Confirm Retirement
This is the step people skip, and it’s the one that actually matters. Buying a credit isn’t the same as retiring it — a credit can sit in a registry, still tradeable, while someone has already claimed the reduction. Retirement is the moment a credit is permanently marked as used on a public registry, given a serial number, and taken out of circulation for good.
On Coffset, retirement happens within 24 hours of purchase, and the serial number generated at that point — not the purchase receipt — is the actual proof that the offset happened. If a platform can’t show you that number, it’s worth asking why.
Putting It Together
A simple example: someone calculates a 500 kg CO2e footprint from a round-trip flight, buys the equivalent credits, and within a day those credits are retired against a specific Verra- or Gold Standard-certified project, with a certificate referencing the retirement serial number. That’s the full loop — measurement, purchase, and permanent retirement — and it’s the same loop underlying any credible offsetting claim, regardless of which platform runs it.
The details worth checking before buying from any provider: which registry retires the credits, how long retirement takes, and whether you get a serial number or just a receipt.
