How to Build Your First Carbon Inventory

Every credible climate strategy starts with the same thing: a clear picture of what you emit today. A carbon inventory is that picture. It tells you where your emissions come from, how big each source is, and where to focus first.

Set your boundaries

Before you count a single tonne, decide what is included. Choose your organisational boundary (which entities and facilities you control) and your operational boundary (which activities you will measure across Scopes 1, 2 and 3). Document these choices so your inventory is consistent and comparable year on year.

Gather activity data

Activity data is simply the real-world numbers behind your emissions: litres of fuel, kilowatt-hours of electricity, kilometres travelled, tonnes of waste. Start with what you already have in utility bills, fuel records, and procurement systems. You will not have everything, and that is fine for a first inventory.

Apply emission factors

Each piece of activity data is multiplied by an emission factor to convert it into carbon-dioxide equivalent. Use recognised, region-specific factors where possible, and keep a record of every source you use.

Prioritise, then improve

Your first inventory will have gaps and estimates. That is normal. The goal is a defensible baseline, not perfection.

A baseline you can stand behind beats a perfect number you never finish.

Focus your effort on the largest sources, replace rough estimates with better data over time, and recalculate as your business changes.

Once your baseline is in place, you can set targets, track progress, and prove your reductions are real. Want a hand building yours? Talk to our team or try the carbon calculator for a quick first estimate.