Track annual carbon from building operations in minutes. Adjust factors for local grids and fuels. Download ready results for audits, bids, and reviews today.
Enter annual activity data and emission factors. Use defaults as a starting point.
Use this example to verify your inputs and compare outputs.
| Item | Example value | Unit | Example factor | Factor unit | Annual CO2e |
|---|---|---|---|---|---|
| Electricity (net after onsite) | 100,000 | kWh/yr | 0.55 | kg/kWh | 55,000 kg |
| Natural gas | 80,000 | kWh/yr | 0.184 | kg/kWh | 14,720 kg |
| Diesel | 2,000 | L/yr | 2.68 | kg/L | 5,360 kg |
| Water | 500 | m³/yr | 0.34 | kg/m³ | 170 kg |
| Refrigerant leakage | 5 | kg/yr | 2088 | kgCO2e/kg | 10,440 kg |
| Example annual total | 85,690 kg (≈ 85.69 t) | ||||
Annual operational carbon is calculated by multiplying activity data by emission factors and summing all sources.
When projection is enabled, activity and selected factors reduce each year:
This produces a geometric series that is summed across the analysis period.
Operational carbon is the greenhouse gas impact from running a facility: electricity, thermal energy, fuels, water services, and refrigerant leakage. This tool totals annual kgCO2e and converts to tCO2e, then reports intensity per square metre and lifetime totals for the chosen analysis period.
Start with utility bills and metering. Electricity and district energy are entered in kWh per year. Natural gas is also in kWh per year, so convert from volume using your supplier’s energy content. Diesel is litres per year, LPG is kilograms per year, and water is cubic metres per year. Refrigerant leakage uses annual kilograms lost.
Emission factors drive results and should be sourced from verified datasets, utility disclosures, or national inventories. As a practical example, a grid factor of 0.55 kgCO2e/kWh applied to 100,000 kWh/yr produces 55,000 kgCO2e/yr. A gas factor of 0.184 kgCO2e/kWh applied to 80,000 kWh/yr produces 14,720 kgCO2e/yr. Record factor sources for audits.
Onsite generation first offsets electricity consumption up to the annual load; any remaining generation is treated as export. Some reporting methods allow an export credit using a defined credit factor. If projection is enabled, the tool applies an annual efficiency improvement rate to activity and a decarbonization rate to selected factors, summing a geometric series across the analysis period.
Use the annual breakdown to target the dominant sources. High electricity or district energy shares often justify envelope upgrades, efficient HVAC, controls, and electrification. Large refrigerant CO2e can outweigh energy savings, so prioritize low-leak systems and lower-GWP refrigerants. Compare intensity (kg/m²·yr) across design options and track lifetime totals to align with client carbon budgets.
Electricity, district energy, and gas are kWh/yr. Diesel is L/yr, LPG is kg/yr, water is m³/yr, and refrigerant leakage is kg/yr. Emission factors must match those units.
Yes. Sum the last 12 months to create annual values. For new buildings, use a modeled annual estimate and update it once measured data becomes available.
Onsite generation offsets purchased electricity first, reducing net grid kWh. Any remaining generation is treated as export, which may be credited only if your reporting method allows it.
Use a factor from your grid operator, utility disclosure, or national inventory for the same year as the consumption data. If reporting requires it, apply location-based or market-based factors accordingly.
Projection reduces activity each year by the efficiency rate and reduces selected emission factors by decarbonization rates. It estimates how emissions may decline over time rather than assuming a constant annual footprint.
Refrigerant CO2e equals leakage (kg/yr) multiplied by the refrigerant’s 100-year GWP (kgCO2e/kg). This can be a major contributor even when energy use is efficient.
It can support early design and scenario comparisons. For formal submission, confirm factor sources, boundaries, and credits against the required standard and document assumptions alongside the exported results.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.