How to Calculate a Carbon Footprint

The basic relationship is emissions = activity data × emission factor. Activity data may be kWh of electricity, litres of fuel, kilometres travelled, or kilograms of material.

Units must match. For example, an electricity factor expressed in kg CO₂e/kWh must be multiplied by consumption in kWh.

Use a factor that matches the location, year, technology, and activity boundary. Electricity factors change as the generation mix changes, so the source year should be shown with the result.

1. Define the subject, period, and boundary.
2. Collect bills, meter readings, fuel records, or other activity data.
3. Convert inputs into consistent units.
4. Apply documented emission factors.
5. Review assumptions and avoid double counting.

In CarbonCAM, you can enter an appliance wattage and daily use duration to estimate energy and CO₂e. Records remain on your device.

Spreadsheets work for small inventories, while specialized tools can improve consistency and audit trails. CarbonCAM focuses on appliance estimates, transparent formulas, local records, daily tasks, and comparable meter-reading savings.