
How our Scope 3 calculation works
Most Scope 3 calculations start with supplier surveys and spreadsheets. They're slow, patchy, and hard to audit.
We take a different approach. We maintain a large dataset of company emissions disclosures, normalised to GHG Protocol standards. We match your suppliers to that dataset, fill gaps with industry data, and give you audit-ready numbers you can use straight away.
We'll walk you through the methodology using live data, emission factors with Q&A

No supplier surveys to get started
Automated Scope 3 solution, implemented in weeks.
Most customers see ROI in under 6 months.
Most customers see ROI in under 6 months.
Most customers see ROI in under 6 months.
The calculation, step by step
We build your Scope 3 footprint through six connected steps. Each step improves coverage, accuracy and consistency.
Company emissions data is collected from public disclosures and verified sources. It's standardised and mapped to GHG Protocol categories.
Where company data is missing, industry averages are used. Ensures full coverage across all suppliers.
Emissions are calculated using spend, sector and activity. Uses company disclosures where available, with revenue-based factors where not.
Company emissions data is collected from public disclosures and verified sources. It's standardised and mapped to GHG Protocol categories.
Companies are mapped into parent and subsidiary relationships. Emissions are assigned to the correct entity.
Where company data is missing, industry averages are used. Ensures full coverage across all suppliers.
Supplier records are matched to a single company profile. Handles duplicates, naming differences and IDs such as DUNS.
Emissions are calculated using spend, sector and activity. Uses company disclosures where available, with revenue-based factors where not.
Each record includes source data, version history and QA checks. Estimates are replaced as better data becomes available.
Explore the methodology
This is the detailed documentation behind our calculation methodology. It's actively maintained, versioned and updated as standards, data sources, and coverage evolve. Every change we make is documented for backwards compatibility.
Frequently asked questions
Get answers to the questions procurement and sustainability teams ask most often.
We prioritise verified primary data from your suppliers. Our system maps over 2m organisations, pulling from public disclosures and direct inputs. Where primary data is missing, we use robust, documented averages to fill coverage gaps. You always see the exact source and calculation method.
DitchCarbon was the first platform to gain 3rd party assurance for its calculations. Every calculation includes full provenance, version control, and change history. You can export evidence packs directly from the platform. This gives you assurable metrics and reduces back-and-forth during the audit process.
We help you close the gap. You can use our supplier portal to send targeted requests with built-in guidance. We minimise new asks by checking existing public data first. For suppliers still unable to report, we provide credible proxy data so your overall Scope 3 baseline remains intact.
We maintain a continuous refresh of supplier data and emission factors - 494,776 of them at last count . When a source updates, our version control tracks the change. You receive anomaly flags for significant shifts, ensuring your baseline remains stable and your reporting stays accurate.
Absolutely. Our platform highlights hotspots where moving from spend-based averages to verified supplier data will make the biggest impact. This allows you to prioritise engagement, improve your data quality score, and base procurement decisions on actual performance rather than estimates.








