# How do I calculate the carbon footprint of wire nails per kg?

Canonical: https://senseible.earth/answers/wire-nails-carbon-footprint-per-kg

Multiply the wire rod per kg of nails by the steel supplier's figure, then add drawing, nail making, polishing and packing energy. Divide the unit's energy by kg dispatched.

## Material

- Wire rod by weight.
- Drawing lubricant.
- Packing.

## Process

- Wire drawing.
- Nail making machines.
- Polishing drums and packing.

## Per kg

Report per kg. The wire rod usually carries most of the footprint.

## Worked example: wire nails unit per kg (one month)

- Electricity: 20,000 kWh x 0.710 = 14,200 kg CO2
- Kg dispatched: 200,000
- Plant total: 14,200 / 200,000 = 0.0710 kg CO2 per kg
- Add wire rod 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 wire drawing footprint](https://senseible.earth/answers/steel-wire-drawing-carbon-footprint-per-tonne)
- [Are steel nails covered by CBAM](https://senseible.earth/answers/are-steel-nails-wire-and-springs-covered-by-cbam)
- [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.