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Whole Life Carbon Calculator
Estimate whole life carbon using EN 15978 lifecycle staging (RICS WLCA 2nd ed, simplified constant operational factor)
Gross internal area (GIA) in m², per RICS/GLA. Used to normalise carbon per m².
Total embodied carbon of all materials (cradle-to-gate) from EPDs or an LCA tool - the largest upfront component.
Annual regulated + unregulated energy carbon: each fuel's kWh/yr × its current DEFRA/DESNZ conversion factor. Uses a constant factor here - see notes for the RICS declining-grid approach.
Carbon of transporting materials from factory gate to site.
On-site construction process carbon: plant, site energy, and construction waste (A5w).
Operational water-supply and treatment carbon per year (often small).
Annualised maintenance/repair (B2-B3) carbon - counts as EMBODIED per EN 15978/RICS, not operational.
Total replacement/refurbishment carbon (B4-B5) over the building life - facades, services, finishes replaced. Often the largest use-stage embodied component.
Demolition, transport, waste processing and disposal carbon (C1-C4). Module D benefits are reported separately and excluded here.
Reference study period (RSP). RICS WLCA 2nd ed default is 60 years for buildings.
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How We Calculate This
Frequently Asked Questions
Whole life carbon (WLC) is the total greenhouse gas emissions associated with a building over its entire life: from material extraction and manufacture (embodied), through operational energy use, maintenance and replacement, to demolition and disposal. It follows the EN 15978 lifecycle stages A-D.
A1-A3: Product manufacture. A4: Transport to site. A5: Construction (incl. waste). B1: Use. B2: Maintenance. B3: Repair. B4: Replacement. B5: Refurbishment. B6: Operational energy. B7: Operational water. C1: Deconstruction. C2: Transport. C3: Waste processing. C4: Disposal. D: Beyond lifecycle (reuse/recycling benefits, reported separately). Crucially, modules B2-B5 (maintenance, repair, replacement, refurbishment) are material-related and count as EMBODIED carbon — only B6 (energy) and B7 (water) are operational carbon. This calculator places B2-B5 in the embodied total accordingly.
RICS first published its Whole Life Carbon Assessment professional statement in 2017. The 2nd edition (a Professional Standard) was published in September 2023 and has been mandatory for RICS members since 1 July 2024. It provides a standardised method aligned with BS EN 15978, sets a 60-year reference study period for buildings, and requires module B6 (operational energy) to be assessed using declining HM Treasury Green Book grid-decarbonisation factors rather than a flat present-day carbon factor. It is increasingly required by planning authorities (e.g. the GLA London Plan).
Embodied carbon (modules A-C, excluding operational B6-B7) is the usual headline target. LETI sets residential embodied targets of ~500 kgCO2e/m² (2020 baseline) reducing to ~300 kgCO2e/m² by 2030. The RIBA 2030 Climate Challenge v2 (2021) sets a domestic embodied 2030 target of <625 kgCO2e/m² (modules A-C, excluding B6-B7) — a minimum 40% reduction from its 1000 kgCO2e/m² business-as-usual benchmark; the non-domestic office equivalent is <750 kgCO2e/m² (from an 1180 kgCO2e/m² benchmark). The GLA London Plan WLCA guidance (Mar 2022) gives a residential A-C benchmark of <1200 kgCO2e/m² (business-as-usual) and an aspirational <800 kgCO2e/m², over a 60-year period. Total whole-life carbon is higher again once 60 years of operational energy (B6) are added on top of embodied carbon.
Key strategies: optimise structural design (less material), use low-carbon materials (timber frame, recycled steel), design for longevity and adaptability, specify energy-efficient systems, use renewable energy, design for deconstruction (enabling material reuse at end of life).
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Last updated: June 2026
Verified against UK standards · estimates only, confirm with your supplier.