Screening GHG calculator

Pick a factor, enter the activity quantity in the unit shown, and get a line-by-line estimate with the source citation attached to every row. Built on the same factor library as the emission factors page.

Which factor set to pick

The dropdown groups factors by category and publisher, because for several activities more than one set publishes a figure and they are not interchangeable. Singapore official factors come first. Where an activity has no Singapore factor at all — business travel, freight, water, waste disposal — the UK DEFRA/DESNZ set is carried as a fallback, and every result that uses one says so.

NEA (Singapore, official) The default for any Singapore regulatory submission. These are the Tier 1 defaults in NEA's GHG Emissions Measurement and Reporting Guidelines, which carbon tax and mandatory reporting are assessed against. Note the energy basis: quantities are per GJ, so you need the fuel's calorific value first.
EMA / NCCS (Singapore grid) Scope 2 location-based electricity in Singapore. The grid emission factor is restated annually, so match the vintage year to your reporting year rather than taking the newest one.
PUB (Singapore water) Water supply and treatment in Singapore.
Carbon Pricing Act (Singapore law) Global warming potentials that are fixed in Singapore law. Where a GWP is prescribed by the First Schedule, it overrides the IPCC value for carbon tax purposes even when a newer assessment report exists.
UK DEFRA / DESNZ (fallback) Use only where Singapore publishes no factor for the activity - business travel, freight, water and waste disposal are the usual cases. These are UK averages: the grid mix, vehicle fleet and waste infrastructure behind them are British, not Singaporean. Disclose the substitution in your methodology note.
GHG Protocol / IPCC Global warming potentials for corporate reporting where no local value is prescribed. Check which assessment report your framework requires - AR5 and AR6 differ materially for several refrigerants.
Company-reported (indicative) Indicative only. A figure taken from one organisation's own sustainability report is not a published factor and should not be used for another entity's inventory.
Derived (not a published factor) Calculated here by combining two cited primary figures. The derivation is stated in the factor's notes. Treat it as an estimate and reproduce it yourself before relying on it.

Set your boundary first

Decide equity share, financial control or operational control before you count anything. Under ISO 14064-1 that is your organisational boundary; under the GHG Protocol it determines which facilities are yours at all.

Match the vintage

Use the factor published for your reporting year. Singapore's grid emission factor changes annually, so a FY2024 inventory should not be run on a FY2021 factor.

Dual-report Scope 2

The GHG Protocol Scope 2 Guidance expects both a location-based and a market-based figure where contractual instruments such as RECs exist. This tool computes the location-based side.