Embodied Carbon Estimator (kgCO2e)

Embodied carbon is the total greenhouse gas emissions, expressed as kg CO2-equivalent (kgCO2e), released by extracting raw materials, manufacturing the product, and transporting it to the construction site — the so-called cradle-to-gate boundary. It does not include operational emissions from running a building (heating, cooling, lighting), nor end-of-life demolition. Embodied carbon is paid up front when you buy and install a material, in contrast to operational carbon which accrues over the building's life.

The factors come primarily from the ICE Database v3 (Hammond & Jones, Inventory of Carbon and Energy, version 3.0, Circular Ecology / University of Bath, 2019). For materials not covered by ICE — bamboo, cob, adobe, rammed earth, thatch, and sandwich-panel cores quoted per m³ — the calculator uses representative published estimates that should be treated as order-of-magnitude figures, not certified values.

Each factor is published per a canonical unit — typically kg, but m³ for structural concrete and panel cores, and L for paint. If the unit you select for an entry does not match the canonical unit, the calculator marks that row as a non-match and contributes 0 kgCO2e to the total, so unit mismatches stay visible. For materials quoted per kg, convert volumetric quantities to mass first using a typical density (e.g. 1,440 kg/m³ for cement, 7,850 kg/m³ for steel).

Embodied carbon factors carry significant uncertainty — typically ±15–30% depending on the supply chain, manufacturing route, and electricity grid mix. Treat the calculated total as an order-of-magnitude figure for design comparisons (e.g. concrete vs timber framing, EPS vs PUF panels). For code-compliance work or formal life-cycle assessment, replace each factor with an Environmental Product Declaration (EPD) for the specific product you are sourcing.

Cradle-to-gate covers raw material extraction (cradle) through to the factory gate where the finished product leaves manufacturing. It is the LCA stages A1 to A3 in EN 15978. It excludes transport to site (A4), construction (A5), use (B), end-of-life (C), and reuse / recycling (D). For long-distance imports — e.g. steel sections shipped across continents — A4 transport can add 5–15% on top of the cradle-to-gate figure.

Earth materials are essentially raw soil with minimal processing — no kilning, no chemical reaction, no high-temperature manufacturing. Their embodied carbon is dominated by transport and on-site labour energy, both of which are small per kg. By contrast, cement-based materials carry the calcination of limestone (which releases CO2 chemically, regardless of fuel) plus high-temperature kilning, putting them 50–100× higher per kg.