Our MRIO data
Why the SWC MRIO is unique
Our Multi-Regional Input-Output model (SWC MRIO) helps you to calculate the most reliable, system-complete carbon footprint. It better enables you to show emission reductions in your supply chain reflected in your reporting. And our transparent methodology and specialist one-to-one support allow you to provide answers and evidence to auditors and other stakeholders.
The SWC MRIO is unique in the market because it delivers the following benefits to you:
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Purchasers' prices as well as basic prices - really important if you want to avoid overestimating your footprint, as it can show more realistic, lower emissions per unit of spend.
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Country of demand as well as country of supply - this provides a more granular understanding and improves the realism of your footprint, accounting for differences between where something is purchased and where it is made.
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Scope 1, 2, 3 breakdown - allows you to swap in company-specific data, essential for capturing reductions in your reporting as your supply chain reduces emissions.
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Time series - you get a time series going back over seven years, giving you the freedom to check progress on past reports, if any kind of methodological changes have occurred.
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System complete – as input-output models are top-down, they are inherently system complete compared to LCA’s, which will always suffer from truncation error. Truncation errors vary for different products, its typically around 26% for paper, but upto 45% for computer equipment. See the different typical truncation errors in different sectors here.
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Country coverage – 75 countries covered (non-estimated) to give you a reflection of your unique supply chain, not averages of UK purchases.
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Sector coverage granularity – 103 sectors, representing a reasonable reflection of available data.
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Standards compliant - Scope 3 emissions data in line with leading global standards including GHG Protocol, SBTi, CDP and ISO 14064.
Other MRIO databases might have some of these elements, but few (if any) contain all of these essential qualities, which together give you the very best estimate of your company’s carbon footprint.
Start with quality data, and you're set up to reach the best carbon targets available to you.
What is an MRIO or Multi-regional input-output model?
When you want to calculate your business carbon footprint, the best and easiest place to start is by looking at what you spend money on. Examining how much you spent on different products and services allows you to gain a broad understanding of where the biggest sources of emissions in your supply chain lie.
Our input-output model provides you with emissions factors which can give you a carbon footprint based on your spend data. Because it covers 75 countries it’s a multi-regional model. And because it gives out emissions factors it’s an environmentally extended model.
If you want to understand more about how input-output models work, and how emissions are broken down into scopes 1, 2 and 3, read our guide to learn how they give the most complete carbon footprint, how they compare to more specific life cycle analysis (LCAs) and how we can hybridise both approaches to give you the most reliable carbon footprint and one that will show your carbon-reduction actions year on year.
Did you know that the data for your carbon footprint is already in your bank statement?
We explain how we use your spend data to calculate your carbon footprint, the strengths and weakness of spend-based and life cycle analysis and how we can hybridise them to get the benefits of both, and what scopes 1, 2 and 3 mean.
SWC MRIO v2.0
Choose your dataset
“ One key benefit of the SWC MRIO is being able to ask the team any queries about any of the emissions factors, and they can talk us through their methodology in detail, unlike other 'black box' datasets.”
Jane Hersey, Group Sustainability Reporting Manager, Savills.
Support to help you use the SWC MRIO
These documents give best-practice guidelines on using the SWC MRIO, based on our 20 years of experience in company supply chain emissions accounting. We also show how the SWC MRIO was developed.
Small World support days
Any licence for our MRIO gives you a personal tuition and consultancy package worth up to £2,500 included in the fee. This upskills your carbon team, ensures your organisation is following best-practice carbon accounting and gives you answers for any queries about your carbon data.
Answers for auditors
Our specialists can be available to answer any queries from auditors or other stakeholders that you disclose your carbon accounts to, allowing you to provide evidence and explanations for every calculation in your emissions data.
We're happy to offer support days as an optional extra to anyone using our SWC MRIO Free.
Things we can help you with include:
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Advice on how to gather your spend data and match it to the sectors in the model.
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Specific use cases for your organisation and your supply chain.
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Advice on individual spend data, when best to use supply basis and when to use demand basis.
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Examining your data to decide when to use basic prices and when to use purchasers' prices.
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Allocating the most appropriate proxy for countries not in the model.
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Bespoke inflation updates for an individual country.
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Addressing any queries from auditors or other stakeholders.
What's new in SWC MRIO v2.0?
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Updated underlying datasets for 2018, 2019 and 2020.
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Inflation-adjusted data for 2021, 2022, 2023 and 2024, including pre and post-COVID adjustments.
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Now covers 75 countries, up from 65.
Improvements in methodology
Maritime shipping emissions: For some countries, our models showed shipping emissions quite a bit higher than those self-reported by the industry. Since v1 of the SWC MRIO, the OECD has also published a maritime model with higher emission levels, supporting our findings. Many countries do not adequately account for ships that sail under another country's flag, even when the ship is owned by them. This often leads to under-reporting for shipping emissions. Our new model contains improved and realistic shipping emissions backed by the OECD’s estimates.
Emissions from oil and gas leaks: Finding data on fugitive emissions, specifically leaks and discharges in the fossil fuel industry, is understandably difficult. Even when totals are known, it is still difficult to assign these to the appropriate industries as emissions can occur anywhere during extraction, processing, and transport. We've employed higher-quality data from the UK and used this to inform improved estimates of fugitive emissions in other countries.
Fluorinated gases: These gases are only used in a few specific industries and account for a small share of emissions but compared to CO2 they have a very high GWP (global warming potential). Here we have again made use of high-quality data from the UK in order to inform a more refined mapping of these gases to the appropriate industries, thus improving our emissions factors.
Radiative forcing factor for aviation: The UK's DESNZ (Department for Energy Security and Net Zero) has reduced the recommended radiative forcing factor for the non-CO2 effects of high-altitude flying since our first model, so we've updated our aviation emissions factors accordingly.
New expanded methodology documentation - November 2025
To increase the level of transparency for the SWC MRIO, we've replaced our condensed methodology with a new expanded methodology.
This more in-depth documentation gives you greater clarity, with a focus on the estimates we use.
Estimates are needed in all MRIO models for countries that don't publish national emissions data, and are one of the reasons why different models can produce sometimes quite different emissions factors. We use a detailed model to construct the emissions ourselves, using freely available data, including the UN energy balances and the EU's EDGAR emissions inventory.
Our datasets are used by
Download the free SWC MRIO v2.0
Fill in the form below to download the free SWC MRIO v2.0 dataset for 2022:
Ask for a SWC MRIO Custom
or SWC MRIO Pro licence
SWC MRIO Custom
SWC MRIO Pro
Tell us a few details about your organisation and we'll get in touch to arrange a call with our MRIO specialists to talk about the data you need and agree your licence details.