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Murat Güven

Embodied carbon calculator

A1–A5 embodied carbon of a building structure per m², with a SCORS rating and a range, from European data. Compare up to three options and share them.

Option A is an example pavilion; option B is the same pavilion with lower-carbon concrete and steel. Change a quantity or a product in either and watch the comparison.

m²£

Option A: Pavilion (IStructE example)

Materials by element. Transport and waste follow the guide’s defaults; change them under each material.

tCO2e

Substructure

33
  • 26
  • 6.9
    t

Frame

19
  • 19
    t

Roof

27
  • 27

Add another element

A1–A5, SCORS A

106 kgCO2e/m²

84 tCO2e in total

A++0–50A+50–100A100–150106B150–200C200–250D250–300E300–350F350–400G≥ 400
After the IStructE SCORS rating (Arnold et al. 2020), redrawn; kgCO2e/m², A1–A5.
Totals for option A, tCO₂e and kgCO₂e per m²
ModuletCO2eper m²
A1–A36379
A4 transport1317
A5w waste23
A5a site67
A1–A584106
Biogenic (apart)-106-134
C1 demolition33
C2 transport22
C3–C4 end of life108136
A–C91115
D (apart)-26-33

A1–A5 by element

  • Substructure33 t
  • Frame19 t
  • Roof27 t

A1–A5 by material

  • Concrete C30/3726 t
  • Rebar, electric arc furnace7 t
  • Steel sections, electric arc furnace19 t
  • Cross-laminated timber27 t
m²£

Option B: Same pavilion, lower-carbon products

Materials by element. Transport and waste follow the guide’s defaults; change them under each material.

tCO2e

Substructure

23
  • 17
  • 6.9
    t

Frame

10
  • 10
    t

Roof

27
  • 27

Add another element

A1–A5, SCORS A+

84 kgCO2e/m²

66 tCO2e in total

A++0–50A+50–10084A100–150B150–200C200–250D250–300E300–350F350–400G≥ 400
After the IStructE SCORS rating (Arnold et al. 2020), redrawn; kgCO2e/m², A1–A5.
Totals for option B, tCO₂e and kgCO₂e per m²
ModuletCO2eper m²
A1–A34657
A4 transport1317
A5w waste22
A5a site67
A1–A56684
Biogenic (apart)-106-134
C1 demolition33
C2 transport22
C3–C4 end of life108137
A–C7392
D (apart)-24-31

A1–A5 by element

  • Substructure23 t
  • Frame10 t
  • Roof27 t

A1–A5 by material

  • Concrete C30/37, blast-furnace cement17 t
  • Rebar, electric arc furnace7 t
  • Steel sections, EAF with renewable power10 t
  • Cross-laminated timber27 t

Comparison

A++A+ABCA · Pavilion (I…Pavilion (IStructE example)106B · Same pavili…Same pavilion, lower-carbon products840100200
A1–A5 in kgCO2e/m² GIA; orange whiskers: P5–P95 of the range; letters: SCORS bands.

Typical new-build structures fall between 150 and 400 kgCO2e/m² (SCORS B to G) (IStructE, 2.3.3).

The guide’s UK factors give 163 kgCO2e/m² for this pavilion; the European factors here give 106.

Method

The calculation follows the IStructE guide How to calculate embodied carbon (2nd edition, 2022): quantities times carbon factors for modules A1–A3, transport to site (A4), waste and site activities (A5); end of life (C1–C4) and module D as the guide sets out, with biogenic carbon and module D always reported separately (EN 15978, EN 15804).

Carbon factors for products come from ÖKOBAUDAT (OBD_2024_II, EN 15804+A2): GWP-fossil plus land use for A1–A3, per kg. Transport, waste and end-of-life defaults are the guide’s. Data and sources lists every dataset.

The rating uses the IStructE SCORS bands on A1–A5 per m² of gross internal area. The range comes from sampling the carbon factors and quantities within the stated spreads (2,000 seeded samples).

I work on life cycle assessment of structures: as a teaching assistant on Life-Cycle Driven Structures at Politecnico di Milano, as co-author of Metals Driving Sustainable Construction (Wiley, forthcoming), and in concApp, an early-stage structural design app that optimizes for cost and embodied carbon.

ReferencesCode

Assumptions and limits

An early-design estimate, not a certified assessment. Structure only: substructure and superstructure.

Generic European factors, mostly German industry averages; specific EPDs will differ. There is no blast-furnace dataset for steel sections in ÖKOBAUDAT: the plates show that route. Hollow sections, precast hollow-core slabs and reused steel need a custom factor.

Transport and waste defaults are UK-based guide values; A5 site activities use a UK cost-based rate and are optional.

The 3rd edition of the guide (2025) splits A5 into four parts, adds an uncertainty factor and allowances for unmodelled items; this tool does not include them yet.

The spreads behind the range are assumptions you can change.

Cite

@software{guven_embodied_carbon,
  author = {Güven, Murat},
  title  = {Embodied carbon calculator},
  year   = {2026},
  url    = {https://likemaestro.github.io/tools/embodied-carbon}
}

References

  1. Arnold, W., Cook, M., Cox, D., Gibbons, O., & Orr, J. (2020). Setting carbon targets: An introduction to the proposed SCORS rating scheme. The Structural Engineer, 98(10), 8–12. doi:10.56330/sqdi8782
  2. CEN (2011). EN 15978: Sustainability of construction works – Assessment of environmental performance of buildings – Calculation method. European Committee for Standardization.
  3. CEN (2019). EN 15804:2012+A2:2019: Sustainability of construction works – Environmental product declarations – Core rules for the product category of construction products. European Committee for Standardization.
  4. Federal Ministry for Housing, Urban Development and Building (2026). ÖKOBAUDAT (Release 2024-II) [Data set]. www.oekobaudat.de/en.html
  5. Gibbons, O. P., Orr, J. J., Archer-Jones, C., Arnold, W., & Green, D. (2022). How to calculate embodied carbon (2nd ed.). The Institution of Structural Engineers.
  6. Robati, M., Daly, D., & Kokogiannakis, G. (2019). A method of uncertainty analysis for whole-life embodied carbon emissions (CO2-e) of building materials of a net-zero energy building in Australia. Journal of Cleaner Production, 225, 541–553. doi:10.1016/j.jclepro.2019.03.339