# How do I calculate the carbon footprint of a ball bearing?

Canonical: https://senseible.earth/answers/ball-bearing-carbon-footprint-per-bearing

Weigh the rings, balls, cage and seals per bearing and multiply by the bearing steel and other suppliers' figures. Add forging or turning, heat treatment, grinding and assembly energy, then divide the plant's energy by bearings made.

## Material

- Bearing steel for rings and balls.
- Steel or polymer cage.
- Rubber seals, metal shields and grease.

## Process

- Turning or forging the rings.
- Hardening and tempering, often in electric or gas furnaces.
- Grinding, honing, assembly and washing.

## Per bearing

Report per bearing by size series and weight. Heat treatment and grinding are often the biggest energy steps, so meter them if you can.

## Worked example: plant energy per bearing (one month)

- Electricity: 200,000 kWh x 0.710 = 142,000 kg CO2
- PNG: 15,000 SCM x 2.05 = 30,750 kg CO2
- Bearings made: 500,000
- Plant total: 172,750 / 500,000 = 0.345 kg CO2 per bearing
- Add bearing steel, cage and seals 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)
- [Forging footprint](https://senseible.earth/answers/forging-carbon-footprint-per-tonne)
- [CNC machined part footprint](https://senseible.earth/answers/cnc-machined-part-carbon-footprint)
- [Automobile industry](https://senseible.earth/industries/automobile)

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 2026-10-21.