Life Cycle Assessment Calculator

Estimate whole-building life-cycle carbon emissions (kgCO2e) across product, construction, use, and end-of-life stages per ISO 14040.

Inputs

Floor Area (sq ft)

Study Period (years)

Embodied Carbon (kgCO2e/ft²)

Construction Carbon (% of A1-A3)

Operational EUI (kBtu/ft²/yr)

Grid Carbon (kgCO2e/kWh)

Maintenance/Replacement (% of A1-A3)

End of Life (% of A1-A3)

Tab to move between fields

Results

Total Life-Cycle Carbon (kgCO2e)

1,999,999

Total Embodied Carbon (kgCO2e)241,500

Operational Carbon (kgCO2e)1,758,499

Embodied Share (%)12.1%

Operational Share (%)87.9%

Carbon Intensity (kgCO2e/ft²/yr)6.67

Total Life-Cycle Energy (MJ)17,758,495

How to Use This Calculator

Enter Floor Area in sq ft and Study Period in years (LEED uses 60 years).
Enter Embodied Carbon Rate in kgCO2e/ft² and Construction Carbon as a percentage of A1–A3.
Enter Annual Operational EUI in kBtu/ft²/yr and Grid Carbon Intensity in kgCO2e/kWh.
Enter Maintenance/Replacement and End-of-Life carbon percentages.
Review Total Life-Cycle Carbon, Embodied vs Operational Carbon split, and Carbon Intensity per ft² per year.

How the result changes with Floor Area (sq ft)

Floor Area (sq ft)	Total Life-Cycle Carbon (kgCO2e)
500,090	200,035,941
1,750,065	700,025,795
3,250,035	1,300,013,619
4,500,010	1,800,003,472

What each input means

Floor Area (sq ft): Total building floor area in square feet.
Study Period (years): Life-cycle assessment study period. LEED uses 60 years; BREEAM uses 60-120 years.
Embodied Carbon (kgCO2e/ft²): A1-A3 embodied carbon per sq ft. Steel frame ~40-50, concrete ~30-45, mass timber ~15-25.
Construction Carbon (% of A1-A3): A4-A5 stage carbon as a percentage of product stage. Typically 3-8%.
Operational EUI (kBtu/ft²/yr): Annual energy use intensity. Office ~50-80, home ~30-50, hospital ~150-250.
Grid Carbon (kgCO2e/kWh): Electricity grid carbon intensity. US avg ~0.4, France ~0.05, coal-heavy ~0.8-1.0.
Maintenance/Replacement (% of A1-A3): B1-B5 maintenance and replacement carbon over the full study period as % of initial embodied.
End of Life (% of A1-A3): C1-C4 demolition and disposal carbon as % of initial embodied. Typically 2-5%.

What each result means

Total Life-Cycle Carbon (kgCO2e): Whole-building GWP across all life-cycle stages.
Total Embodied Carbon (kgCO2e): Sum of A1-A5, B1-B5, and C1-C4 stages.
Operational Carbon (kgCO2e): B6 stage: operational energy carbon over the study period.
Embodied Share (%): Percentage of total carbon from embodied sources.
Operational Share (%): Percentage of total carbon from operational energy.
Carbon Intensity (kgCO2e/ft²/yr): Annualized carbon per square foot over the study period.
Total Life-Cycle Energy (MJ): Combined embodied and operational energy over the study period.

How this is calculated

Worked example, using the default values

Identify Input Parameters
4 parameters
Floor Area (sq ft) = 5000, Study Period (years) = 60, Embodied Carbon (kgCO2e/ft²) = 35, Construction Carbon (% of A1-A3) = 5 = 8 input(s) provided
Calculate Total Life-Cycle Carbon
Total Life-Cycle Carbon = a1a3Carbon + a4a5Carbon + b1b5Carbon + b6Carbon + c1c4Carbon
1999999 = 1999999
Calculate Total Embodied Carbon
Total Embodied Carbon = a1a3Carbon + a4a5Carbon + b1b5Carbon + c1c4Carbon
241500 = 241500
Calculate Operational Carbon
Operational Carbon = annualOperationalCarbon * studyPeriod
1758499 = 1758499

Engine last updated July 26, 2026. Checked against 2 independently-derived tests — how we verify calculators.

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Embodied Carbon Calculator

Calculate A1-A3 embodied carbon (kgCO2e) for your building's structural and envelope materials — concrete, steel, timber, masonry, glass, and insulation.

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