# Our steel product is cut from a coil before export. Do we use the mass before or after cutting for CBAM?

Canonical: https://senseible.earth/answers/cbam-precursor-mass-before-cutting-steel

Before cutting. To work out the embedded emissions of a steel precursor, the Carbon Border Adjustment Mechanism (CBAM) uses the mass that entered your production process, not what is left after cutting. Cutting itself sits outside the iron and steel boundary, so its own fuel and power are not added.

## What the Commission says

Your buyer's team asks for the tonnes on your coil invoice, and your shear line scraps a few percent of every coil. The Commission's CBAM Questions and Answers, question 4.11, covers exactly this. Cutting is excluded from the system boundary for iron and steel goods, so the electricity and fuel your cutting line uses are not counted.

But to compute the embedded emissions of the precursor, you use the mass of the precursor as it entered the production process, before cutting. The Q&A adds that this holds even though the emissions from cutting are not accounted for in the final good.

## Why it changes your number

Every tonne of coil you bought arrives with its own embedded emissions. If you counted only the tonnes left after cutting, you would drop the emissions of the off-cuts that never left your gate. The Q&A closes that door: all the coil's emissions go onto the tonnes you ship, so the figure per tonne of cut product comes out slightly above the figure per tonne of coil.

## What to keep for your verifier

- The coil purchase invoice with tonnes, mill and heat or coil numbers.
- Your supplier's embedded emissions per tonne: a verification report if it has one, otherwise the default value.
- Weight at your gate and the tonnes of cut product dispatched, so tonnes in and tonnes out reconcile.
- A line on what happened to off-cuts. The Q&A does not say how sold or recycled scrap is treated, so agree this with your verifier before you rely on the example below.

## Example: a cut-to-length line (example figures)

- Coil bought: 1,000 t, supplier figure 2.000 t CO2e per tonne (an example, not a default value)
- Cut product shipped: 940 t. Off-cuts: 60 t
- Mass before cutting: 1,000 t x 2.000 = 2,000 t CO2e
- Figure on the cut product: 2,000 / 940 = 2.128 t CO2e per tonne
- Using the mass after cutting would give 940 x 2.000 / 940 = 2.000, about 6% lower, and does not follow the Q&A

Example numbers only. CO2e means carbon dioxide equivalent. It shows the mass rule from question 4.11 and assumes no credit for off-cuts.

## What Senseible does here

Senseible reads coil purchase invoices and freight records into dated records, so tonnes in are traceable to a document. The CBAM suite builds the verifier-ready file from them and every figure is checked in-house; an accredited verifier Senseible partners with signs it off, or you send it to your own.

- [Only cutting or welding bought steel](https://senseible.earth/answers/cutting-only-unit-cbam-verification)
- [Splitting a plant into production processes](https://senseible.earth/answers/cbam-installation-split-into-production-processes)
- [CBAM suite](https://senseible.earth/cbam-suite)

Sources: [European Commission, CBAM Questions and Answers (updated 15 October 2026), question 4.11](https://taxation-customs.ec.europa.eu/document/download/013fa763-5dce-4726-a204-69fec04d5ce2_en?filename=CBAM_Questions%20and%20Answers.pdf)

Last reviewed 2026-11-04. The Commission updates the Q&A often; re-check question 4.11 when a new version is published.