Getting started with your carbon footprint doesn’t have to be complicated. Manufacturers across New Zealand are already sitting on one of the most powerful tools for understanding their emissions: their financial data.

Spend-based emission factors turn dollars spent into practical emissions estimates, providing you with a fast, accessible way to start measuring and managing your impact. They’re especially helpful for scope 3 emissions from your supply chain, which are typically the hardest to track but often make up the biggest part of your footprint.

In this article, we explain what spend-based emission factors are, how you can use them in your business, and where to find the most accurate and up-to-date data for New Zealand.

What are spend-based emission factors?

Spend-based emission factors are a type of emissions data that connect greenhouse gas emissions with how much money you spend on goods and services. They express emissions as kilograms of carbon dioxide equivalent (CO₂-e) per dollar spent (kg CO₂-e/$).

They’re calculated using environmentally-extended input-output (EEIO) models. These models look at the total emissions of a sector (like “fabricated metal products” or “office furniture”) and divide this by the total revenue of that sector. The result is an average emissions intensity per dollar.

In simple terms, they give you a ballpark figure: if you know how much you spent in a certain category, you can estimate the emissions that came with it.

Why use them?

Spend-based emission factors are especially helpful when:

→You don’t have access to physical data (like litres of fuel or kilograms of steel)

→You need an emissions estimate based on financial records

→You’re starting your emissions reporting and want to cover as much ground as possible

→You want to identify emissions hotspots in your supply chain before doing a deeper dive.

They’re widely used for:

→Scope 3 reporting (especially for purchased goods and services and financed emissions)

→Understanding emissions from procurement and investments

→Estimating your personal or household carbon footprint

Practical examples

Let’s say that in the 2024-25 financial year your business spent:$100,000 on construction services: Using an emissions factor of 0.206 kg CO₂-e per dollar, this equates to 20,600 kg CO₂-e. $10,000 on software subscriptions: With a lower emissions factor of 0.077 kg CO₂-e per dollar, this works out to 770 kg CO₂-e.$50,000 on imported electronic components:

These may have a different emissions profile depending on where they’re sourced. A factor of 0.140 kg CO₂-e per dollar gives 7,000 kg CO₂-e.These estimates help you understand where emissions are likely to be high so you can focus your efforts on what matters most.

How to use spend-based emission factors

Spend-based emission factors are best used as a stepping stone, not the final destination.

Think of them as a practical tool to start measuring and managing your emissions when you’re missing detailed data. Over time, you can replace them with more accurate activity- based or supplier-specific data where it matters.

They’re also helpful as a gap filler. For example, you might have high-quality data for major inputs (like electricity or fuel), but little detail for indirect costs (like professional services or IT). Spend-based factors help you cover these smaller items without making the data collection process too complicated.

Tips for using them effectively:

→Be transparent about your methods and explain when and why you’ve used spend- based data.

→ Refine over time and improve your data where it makes the biggest impact.

About thinkstep-anz’s spend-based emission factors

Trans-Tasman sustainability firm thinkstep-anz has developed a set of spend-based emission factors tailored to the New Zealand economy. They’re built using local data from Statistics New Zealand, the Ministry for the Environment, and the Reserve Bank of New Zealand.

For imports, we use a global database (Eora) to model emissions from overseas supply chains.

The latest (2025) release includes:

→Industry-level factors: for spend aligned to economic sectors (excluding taxes and retail margins)

→Commodity-level factors (basic prices) – for purchases direct from producers

→Commodity-level factors (purchaser’s prices) – for retail transactions including GST and margins

Free vs commercial access

There are two licence options:

→The free licence gives you access to industry and commodity emissions factors for 2018 and 2021. It’s great for internal use, with peer-reviewed data.

→The commercial licence includes everything in the free version, plus additional years (2022 and 2023), audited data (for 2023), customer support and the ability to integrate with software tools. It’s designed for organisations that need reliable, up-to-date data for commercial projects or digital platforms.

Get started

To download the emission factors or learn more, visit our website:

www.thinkstep-anz.com

 

If you have questions or need help choosing the right factors, email us at  data@thinkstep-anz.com 

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