# How do I calculate the carbon footprint of a steel trunk?

Canonical: https://senseible.earth/answers/steel-trunk-carbon-footprint-per-piece

Weigh the steel sheet per trunk, including offcuts, and multiply by the steel supplier's per-kg figure. Add pressing, welding, painting and oven energy, then divide the unit's energy by trunks made.

## Materials

- Cold rolled steel sheet by weight.
- Hinges, latches and handles.
- Paint or powder.

## Process

- Shearing, bending and spot welding.
- Pretreatment and painting.
- Paint oven and packing.

## Per piece

Report per trunk by size and sheet gauge.

## Worked example: steel trunk unit per piece (one month)

- Electricity: 8,000 kWh x 0.710 = 5,680 kg CO2
- LPG: 600 kg x 2.98 = 1,788 kg CO2
- Trunks made: 3,000
- Plant total: 7,468 / 3,000 = 2.489 kg CO2 per piece
- Add steel sheet and paint for the full figure

Inputs are illustrative; use your own bills and production records.

## What Senseible does here

Senseible reads the plant's electricity bills (CEA grid factor 0.710 kg CO2 per kWh, CO2 Baseline Database version 21.0) and fuel invoices (IPCC 2006 defaults) into a fingerprinted Scope 1 and 2 record, the plant-level input to a per-unit figure. Bought-in materials go to the supplier evidence trail; product reports are self-declared drafts.

- [Product carbon footprint calculator](https://senseible.earth/calculators/product-carbon-footprint)
- [Steel almirah footprint](https://senseible.earth/answers/steel-almirah-carbon-footprint-per-unit)
- [Sheet metal stamping footprint](https://senseible.earth/answers/sheet-metal-stamping-carbon-footprint-per-kg)
- [Steel industry](https://senseible.earth/industries/steel)

Sources: [GHG Protocol Product Standard](https://ghgprotocol.org/standards), [ISO 14067:2018, Carbon footprint of products (iso.org)](https://www.iso.org), [IPCC 2006 Guidelines, Volume 2 Energy (fuel defaults)](https://www.ipcc-nggip.iges.or.jp/public/2006gl/vol2.html), [CEA CO2 Baseline Database, version 21.0](https://cea.nic.in/cdm-co2-baseline-database/?lang=en)

Last reviewed 2026-10-20.