# Our coal test report shows as-received and air-dried values. Which do we use for emissions?

Canonical: https://senseible.earth/answers/coal-as-received-vs-air-dried-basis

Use the basis that matches the weight you are multiplying. Coal is usually weighed as received, wet, so pair that weight with the as-received calorific value or carbon content. Pairing a wet weight with an air-dried value overstates emissions, because the air-dried figure assumes less water per tonne.

## The bases on a report

- As received: the coal as delivered, with all its moisture.
- Air dried: after surface moisture has evaporated in the lab.
- Dry or dry ash free: with no moisture at all.

## Converting between them

Lab reports often give the moisture for each basis. A value can be converted using the ratio (100 minus moisture on the target basis) divided by (100 minus moisture on the reported basis).

## What a verifier checks

That the weight and the calorific value are on the same basis, and that the test report covers the same deliveries as the invoices.

## What Senseible does here

Senseible reads fuel invoices, gas bills and delivery documents into dated, fingerprinted records, so each tonne of CO2 traces back to the document behind it.

- [GCV vs NCV](https://senseible.earth/answers/gcv-vs-ncv-in-fuel-emission-calculation)
- [Indian coal emissions by GCV](https://senseible.earth/answers/indian-coal-emissions-by-gcv)
- [Coal weighbridge vs invoice](https://senseible.earth/answers/coal-weighbridge-weight-vs-invoice-quantity)

Sources: [IPCC 2006 Guidelines, Volume 2 Energy](https://www.ipcc-nggip.iges.or.jp/public/2006gl/vol2.html), [IPCC 2006 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.