Calculate total CO₂e emissions in your concrete mix — by PSI strength, SCM replacement (fly ash, slag, silica fume), volume & transport. Based on NRMCA 2023 national EPD and ICE v3.0 carbon intensity data.
Fill in all fields and click Calculate to get your total embodied carbon with EPA equivalencies.
Higher PSI = more cement content = higher CO₂e per cubic yard.
SCM replacements cut embodied carbon significantly. Fly ash and slag are most common in US ready-mix.
1 yd³ = 27 cubic feet. Divide total cubic feet by 27 to get cubic yards.
Used to tailor project-specific carbon reduction recommendations.
Transport (A4 stage) adds ~0.5–3.5% to total embodied carbon. Shorter hauls = lower carbon.
Embodied carbon in concrete refers to the total greenhouse gas emissions generated during the full upstream lifecycle — from raw material extraction and cement manufacturing through batching, transport, and delivery to the job site (lifecycle stages A1–A4). According to the National Ready Mixed Concrete Association (NRMCA), US concrete production generates approximately 1.5 billion cubic yards annually, making it one of the largest single contributors to construction sector embodied carbon in the country. Unlike operational carbon (building energy use), embodied carbon is locked in at the time of construction — making mix specification decisions at the design stage the only effective moment to reduce it.
Cement makes up only 10–15% of a concrete mix by weight, but contributes approximately 87% of total embodied carbon. Portland cement production involves two major unavoidable CO₂ sources: chemical calcination of limestone (~0.50 kg CO₂/kg of cement regardless of fuel type) and kiln thermal energy requirements. Replacing cement with supplementary cementitious materials — fly ash at 0.004 kg CO₂e/kg and slag at 0.07 kg CO₂e/kg versus OPC at 0.93 kg CO₂e/kg — delivers dramatic carbon reductions at low or no cost premium in most US markets.
Fly ash is the most widely used SCM in US ready-mix concrete — a by-product of coal-fired power plants. Class F fly ash (Eastern and Midwestern USA) can replace 15–25% of Portland cement. At ~0.004 kg CO₂e/kg, fly ash carries essentially zero primary embodied carbon, cutting mix carbon by 10–28% depending on replacement rate.
Ground granulated blast-furnace slag — a steel manufacturing by-product — is widely available across the US Midwest, Great Lakes, and Gulf Coast. At ~0.07 kg CO₂e/kg, slag can replace 30–50% of Portland cement, cutting embodied carbon by 22–38% while improving long-term durability and sulfate resistance.
Silica fume is used at 5–10% replacement levels to achieve very high compressive strengths (6,000–12,000 PSI) in bridge decks, parking structures, and marine applications. At ~0.14 kg CO₂e/kg — far below OPC — its use at typical dosages reduces embodied carbon by 3–7% relative to pure OPC high-strength mixes.
The calculation approach in this tool follows the Environmental Product Declaration (EPD) framework established by ASTM E2921 and ISO 14044, using published NRMCA 2023 industry EPD and ICE v3.0 database carbon intensity factors. These are appropriate for US residential and commercial project estimating.
This calculator uses NRMCA national average carbon intensity values. For LEED v4/v4.1 MRc2 credits, Buy Clean California compliance, or Federal Buy Clean Initiative procurement, you must use a verified plant-specific Environmental Product Declaration (EPD) from your ready-mix supplier. Most major US ready-mix producers now offer plant-specific EPDs on request — and actual plant-level carbon can vary 15–35% from the national average. Compare suppliers free at Building Transparency EC3.
Average embodied carbon intensities for common US ready-mix mixes and SCM blends in both US imperial (lb CO₂e/yd³) and SI (kg CO₂e/m³) units. Values sourced from NRMCA 2023 national industry EPD and ICE v3.0 database.
| Mix Type / SCM Blend | Strength | lb CO₂e / yd³ | kg CO₂e / m³ | vs. OPC Baseline | Status |
|---|---|---|---|---|---|
| 100% OPC (Baseline) | 3,000 PSI | 570 | 338 | — Reference | NRMCA Avg EPD |
| 15% Fly Ash (Class F) | 3,000 PSI | 513 | 304 | –10% | LEED Eligible |
| 25% Fly Ash (Class F) | 3,000 PSI | 467 | 277 | –18% | LEED Eligible |
| 40% Fly Ash (Class C) | 3,000 PSI | 410 | 243 | –28% | LEED Eligible |
| 30% Slag Cement (GGBFS) | 3,000 PSI | 445 | 264 | –22% | LEED Eligible |
| 50% Slag Cement (GGBFS) | 3,000 PSI | 353 | 209 | –38% | LEED Eligible |
| Blended 25% FA + 25% Slag | 3,000 PSI | 371 | 220 | –35% | LEED Eligible |
| 8% Silica Fume | 5,000–6,000 PSI | 722–798 | 428–473 | High-strength req. | Verify EPD |
| Bagged Concrete (80 lb bags) | ~4,000 PSI | 748 | 443 | +31% vs. ready-mix | No EPD available |
| High-Strength OPC | 6,000 PSI | 840 | 498 | +47% vs. 3,000 PSI | NRMCA EPD |
Ask your ready-mix supplier for an Environmental Product Declaration (EPD) specific to their plant. Plant-level carbon intensity can vary 20–35% below the NRMCA national average depending on local SCM availability, fuel mix, and plant efficiency. EPDs from US suppliers are increasingly available at no cost on request.
For residential and commercial slabs, specify 25–40% fly ash or 30–50% slag replacement in your mix design. Most US ready-mix suppliers in major metro areas can supply high-SCM mixes at the same price or within a 5–10% premium — the 18–38% carbon savings far outweigh the small cost increase on most projects.
Transport (Stage A4) accounts for 1.5–3.5% of concrete's total embodied carbon. Sourcing from a plant within 15 miles reduces transport emissions up to 60% compared to long-haul delivery. Combine the lowest-carbon mix EPD with a short haul for the best overall carbon outcome on any US project.
Under LEED v4.1 MRc2 (Building Product Disclosure and Optimization — EPDs), projects earn credits by using concrete with a verified EPD demonstrating a carbon intensity at least 10% below the NRMCA industry average. For most US projects, specifying a 25% fly ash or 30% slag mix and obtaining the supplier's EPD is sufficient. Visit the US Green Building Council (USGBC) for the latest credit requirements.
Official databases, EPD programs, and engineering guides used by US engineers, architects, and green building professionals.
The National Ready Mixed Concrete Association publishes the US concrete industry's official Environmental Product Declarations, carbon reduction roadmaps, and the NRMCA Carbon Calculator tool — the basis for the national average data used in this calculator.
NRMCA SustainabilityBuilding Transparency's EC3 tool is the most comprehensive free database of verified concrete EPDs in the USA — allowing specifiers to compare actual plant-level carbon intensities across thousands of US ready-mix suppliers and find the lowest-carbon option in any US region.
Open EC3 ToolLEED v4.1 MRc2 requires EPD-documented concrete carbon at least 10% below the NRMCA industry average. This resource explains exactly what documentation is needed and how to earn the credit for concrete on LEED-registered projects in the USA.
LEED MRc2 Guide