# Can I use my coal's lab carbon content instead of a default factor?

Canonical: https://senseible.earth/answers/coal-ultimate-analysis-carbon-content-factor

Yes, and it is often more accurate. If a lab gives the carbon percentage on an as-received basis, CO2 equals carbon mass times 44/12, with full oxidation as the IPCC 2006 default assumes. Use the same basis as the weight you burned, and test each lot or a fixed schedule.

## The formula

CO2 (t) = coal burned (t, as received) x carbon fraction (as received) x 44/12.

## Get the basis right

- Air-dried or dry-basis results must be converted to as-received using total moisture.
- Sample to a written method, so results represent the lot.
- Keep lab certificates with the invoices.

## When a default is fine

For small users, the IPCC default by coal type or a GCV-based estimate is accepted. State which you used.

## Worked example (illustrative)

- Coal burned: 1,000 t as received
- Carbon content (as received): 45%
- CO2: 1,000 x 0.45 x 44/12 = 1,650 t

Illustrative carbon content. Use your own lab result on the same basis.

## What Senseible does here

Senseible keeps each bill and invoice behind every figure, dated and fingerprinted, so a reviewer can trace a number back to the document it came from.

- [Indian coal by GCV](https://senseible.earth/answers/indian-coal-emissions-by-gcv)
- [As received vs air dried](https://senseible.earth/answers/coal-as-received-vs-air-dried-basis)
- [Tier 1 default factor](https://senseible.earth/answers/ipcc-tier-1-default-factor-good-enough)

Sources: [2006 IPCC Guidelines, Volume 2 Energy](https://www.ipcc-nggip.iges.or.jp/public/2006gl/vol2.html), [2006 IPCC Guidelines for National Greenhouse Gas Inventories](https://www.ipcc-nggip.iges.or.jp/public/2006gl/), [GHG Protocol Corporate Standard](https://ghgprotocol.org/corporate-standard)

Last reviewed 2026-10-22.