Emissions Trading Calculator

A cap-and-trade system sets a maximum (cap) on the total greenhouse gas emissions allowed across a regulated sector. Companies receive or buy allowances equal to their cap. If they emit less than their cap, they can sell surplus credits; if they emit more, they must buy additional credits from the market or face penalties.

Start by identifying all emission sources across your operations — energy consumption, transportation, industrial processes, and supply chain (Scope 1, 2, and 3). Apply the relevant emission factors from recognised standards such as the GHG Protocol. Sum all sources in tonnes of CO₂ equivalent (tCO₂e) to get your annual footprint, which is your 'actual emissions' figure in this calculator.

One carbon credit represents the right to emit one tonne of CO₂ equivalent. Prices are set by supply and demand on carbon markets such as the EU ETS, California Cap-and-Trade, or voluntary markets. Prices vary widely — EU ETS allowances have traded between €50 and €100+ per tonne in recent years, while voluntary market credits can range from a few dollars to over $50.

If your actual emissions exceed your allocated cap (after any planned abatement), you are in a 'deficit' position and must purchase enough carbon credits to cover the shortfall before the compliance deadline. Failure to do so results in regulatory penalties — for example, the EU ETS charges approximately €100 per tonne of uncovered excess emissions, plus you still owe the credits.

A surplus means your cap plus planned abatement exceeds your actual emissions — you have credits left over that you can bank for future periods or sell on the open market for revenue. A deficit means your actual emissions exceed your cap minus abatement, so you need to purchase additional credits to remain compliant.

Internal abatement (reducing your own emissions through efficiency improvements, fuel switching, or renewable energy) has an upfront cost but permanently reduces your compliance burden. Buying credits is faster but depends on market prices. The most cost-effective strategy is usually to abate internally where your abatement cost is lower than the carbon price, and buy credits for the remaining deficit.

This calculator supports scenario modelling for the EU Emissions Trading System (EU ETS), California Cap-and-Trade, the Regional Greenhouse Gas Initiative (RGGI) in the US Northeast, the UK Emissions Trading Scheme (UK ETS), China's National ETS, and voluntary carbon markets. Select your scheme to apply the appropriate market context to your calculations.

Yes. Select 'Voluntary Carbon Market' as your trading scheme. Voluntary credits (such as Verra VCS or Gold Standard offsets) are typically priced lower than compliance market allowances. The calculator will still show your net position, total credit cost, and cost per tonne, giving you a clear picture of what it would cost to offset your emissions voluntarily.