# How do I calculate the carbon footprint of a spanner or other hand tool?

Canonical: https://senseible.earth/answers/spanner-hand-tool-carbon-footprint-per-piece

Take the steel bar per tool, including flash and scale lost in forging, and multiply by the steel supplier's per-kg figure. Add forging furnace fuel, heat treatment, machining and plating electricity, then divide by tools passed.

## Steel and forging

- Alloy steel bar by weight per tool, including flash.
- Forging furnace fuel or induction heater electricity.
- Trimming presses and shot blasting.

## Finishing

- Hardening and tempering furnaces.
- Grinding, polishing and chrome or nickel plating.
- Blister cards, rolls and cartons.

## Per piece

Report per tool with its weight. Group tools by weight band rather than one average across a whole catalogue.

## Worked example: spanner and hand tool unit per piece (one month)

- Electricity: 45,000 kWh x 0.710 = 31,950 kg CO2
- PNG: 6,000 SCM x 2.05 = 12,300 kg CO2
- Tools passed: 120,000
- Plant total: 44,250 / 120,000 = 0.369 kg CO2 per piece
- Add steel and plating 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)
- [Are hand tools covered by CBAM](https://senseible.earth/answers/are-hand-tools-covered-by-cbam)
- [Forging footprint](https://senseible.earth/answers/forging-carbon-footprint-per-tonne)
- [Electroplating footprint](https://senseible.earth/answers/electroplating-carbon-footprint-per-square-metre)
- [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.