Calculate Scope 1 mobile combustion emissions from fleet & transport using DEFRA 2025 factors. Free, GHG Protocol aligned, kg CO2e output, a
The same litre of diesel can land in three different places on your carbon inventory. Burned in a company van, it's Scope 1 mobile combustion. Burned in a fixed standby generator, it's Scope 1 stationary. Burned in a courier's own vehicle, it's Scope 3. The chemistry is identical — DEFRA's 2025 factor is 2.57082 kg CO₂e per litre either way — but the asset class decides the line, and misclassifying it is one of the most common Scope 1 audit findings.
This calculator runs the DEFRA 2025 factor set across all 15 mobile fuels — diesel, petrol, LPG, marine grades, aviation, CNG, LNG — and bundles the CO₂, methane, and nitrous oxide into a single CO₂e value automatically. Pick your fuel and unit basis (litres, tonnes, or kWh), enter the quantity, and it returns an audit-ready figure with the full calculation chain exportable for verification.
One genuinely useful detail it gets right: it inherits DEFRA's native AR5 GWP basis rather than silently "converting" to AR6, which keeps a single factor honest to its source even in an AR6 inventory.
Try it on GreenCalculus.
