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Building Carbon Emission Footprint Calculator

The Building Carbon Emission Footprint Calculator estimates annual operational emissions from electricity use, fuel or gas energy use, and an optional additional emissions amount. It is intended for building owners, facility teams, tenants, analysts, or students who have energy consumption data and emissions factors that match the location and accounting approach being used.

The calculator does not embed universal electricity or fuel factors because those values can vary by grid, supplier, fuel type, year, and reporting method. Instead, you provide the factors in kilograms of CO2e per kWh. The output separates electricity, fuel, and other emissions, making it easier to see which energy source contributes most to the estimated building footprint.

Inputs

kWh
kgCO2e/kWh
kWh
kgCO2e/kWh
kgCO2e
Result
—
Estimated annual building emissions
Electricity emissions—
Fuel / gas emissions—
Other emissions—

1. Enter annual electricity use
Provide electricity consumption in kWh for the building and reporting year.

2. Apply the electricity emissions factor
Enter a kgCO2e/kWh factor consistent with the grid, supplier, and accounting basis you are using.

3. Enter fuel or gas energy use
Use kWh-equivalent energy consumption for the fuel or gas category represented by the selected factor.

4. Apply the fuel factor
Enter the corresponding kgCO2e/kWh emissions factor.

5. Add other emissions if needed
Enter any additional annual operational emissions already calculated in kgCO2e, such as another source that is outside the two energy fields.

6. Review the source breakdown
The result reports total tCO2e per year and separates electricity, fuel, and other contributions.

Electricity emissions = Electricity use × Electricity factor Fuel emissions = Fuel energy use × Fuel factor Total emissions (kgCO2e) = Electricity emissions + Fuel emissions + Other emissions Total emissions (tCO2e) = Total emissions (kgCO2e) ÷ 1,000

Electricity use — annual electricity consumption in kWh.

Electricity factor — kgCO2e per kWh of electricity.

Fuel energy use — annual fuel or gas energy in kWh.

Fuel factor — kgCO2e per kWh of the selected fuel basis.

Other emissions — additional annual emissions already expressed in kgCO2e.

Assumptions: Factors must use compatible scopes and units. Electricity factors may differ under location-based and market-based accounting, while fuel factors vary by fuel and methodology.

What the result means

Use the main result together with the breakdown to understand the calculated scenario at the exact scope and units entered.

Building emissions depend on energy data quality, factor selection, and accounting scope.

Given

  • Electricity use: 320,000 kWh
  • Electricity factor: 0.31 kgCO2e/kWh
  • Fuel / gas energy use: 140,000 kWh
  • Fuel factor: 0.185 kgCO2e/kWh
  • Other emissions: 4,500 kgCO2e

Calculation
Electricity emissions = 320,000 × 0.31 = 99,200 kgCO2e
Fuel emissions = 140,000 × 0.185 = 25,900 kgCO2e
Total = 99,200 + 25,900 + 4,500 = 129,600 kgCO2e
Total = 129,600 ÷ 1,000 = 129.6 tCO2e

Result
129.60 tCO2e/year estimated building emissions.

Electricity contributes the largest share in this example. The result can be used as a baseline for energy-efficiency or decarbonization planning when the factors match the intended accounting method.

Why does the calculator ask me to enter emissions factors?

Electricity and fuel factors can vary by geography, supplier, fuel, year, and methodology. User-entered factors prevent the page from implying that one universal value applies everywhere.

Can I enter natural gas consumption in therms or cubic meters?

Not directly. Convert the fuel quantity to kWh, or first calculate emissions separately and place the result in the other-emissions field.

Does this include embodied carbon from construction materials?

No. The inputs are designed for operational energy emissions plus an optional added annual emissions amount. Embodied carbon requires a different lifecycle calculation.

What is the difference between location-based and market-based electricity accounting?

They can use different emissions factors for the same electricity consumption. Use the factor required by the reporting approach you intend to follow.

Can I use monthly data?

Yes, if every input and factor covers the same monthly period. The result label says annual, so for a true annual footprint you should sum or annualize consistent 12-month data.