Concrete Carbon Impact Estimator (per m³)
Indicative cradle-to-gate (A1–A3) carbon estimate for one cubic metre of concrete, using BS 8500/EN 197-1 cement notation. Enter quantities (or arrive from the calculator pre-filled) and adjust the emission factors to match your supplier's EPD.
Quantities and factors
| Material | Quantity (kg/m³) | Factor (kg CO₂e/kg) | kg CO₂e/m³ |
|---|---|---|---|
| Total (materials, A1–A3) | — | ||
Carbon summary
Vs 100% CEM I baseline
| Basis | kg CO₂e/m³ |
|---|---|
| Your mix | — |
| 100% CEM I baseline | — |
| Difference | — |
| Difference (%) | — |
Notes and limitations
Indicative estimates for comparing mix options during preliminary design. This is not a certified Environmental Product Declaration (EPD — a manufacturer's verified environmental data sheet), not a full life-cycle assessment (LCA), and not a verified A1–A3 declaration under EN 15804/ISO 14025.
Figures cover cradle-to-gate (A1–A3, i.e. raw material supply, transport to the cement/aggregate producer and manufacture) of the constituent materials only. They exclude batching-plant energy, formwork, reinforcement, pumping/placing, curing, in-service carbonation uptake (CO₂ concrete reabsorbs from the air over its life) and end of life.
The cement factor dominates — typically 80–95% of the total. Your supplier's actual EPD matters far more than refining the aggregate figures.
SCM (supplementary cementitious material, e.g. GGBS or PFA) factors are highly sensitive to the allocation method used to attribute emissions to a by-product; published figures can differ by an order of magnitude, hence the wide ranges shown.
Check the current published figure — the MPA/BRMCA UK factsheet and the ICE Database — rather than relying on the defaults here.
A lower carbon figure does not make a mix compliant. Strength class, exposure/durability limits (BS 8500/EN 206) and early-age performance still govern the design.
Using this estimate on UK projects
UK clients increasingly ask for embodied-carbon figures at design stage, often following PAS 2080 (carbon management in buildings and infrastructure) or the Institution of Civil Engineers' Low Carbon Concrete Routemap. The Routemap proposes a classification of concrete by embodied carbon so that specifiers can ask for a carbon band rather than a particular recipe. This page gives an indicative A1–A3 figure to compare options early; once a producer is selected, replace it with the producer's EPD or mix-specific data.
The biggest UK levers, in order
- Cement and combination type — GGBS and fly ash combinations, and the newer lower-clinker cements covered by BS 8500:2023, usually cut A1–A3 carbon more than any other single change. Check early-age strength and striking times.
- Strength class — do not specify a higher class than structure and durability require; each step up usually means more binder.
- Allowing 56-day strength for elements that are not loaded early can let a producer use more SCM.
- Aggregate and transport — usually a smaller share, but local sourcing and recycled aggregates help at the margin.
Reporting honestly
State the system boundary (A1–A3 per m³), the source of each factor and the date. Do not present this estimate as an EPD or use it for a formal carbon declaration. If a supplier's figure differs from this page, the supplier's verified data should be used.