Carbon footprint calculators – what to ask to help you choose

Knowing the carbon footprint of your farm is becoming increasingly important. Some processors and buyers are already asking for footprints as part of their environmental obligations, and the number is likely to increase. A carbon footprint can show the greenhouse gas (GHG) emissions hotspots in a business and where improvements should be made. Additionally, being able to show positive change in your footprint has the potential to bring extra income in the future, such as through the carbon markets.

There are many carbon footprint calculators out there. You should make sure that you pick the right tool for you. Below, we have provided some important questions you should ask when choosing a carbon footprint calculator tool.

It is important that a consistent record of your footprint over time can be made, starting with a baseline, so it is best to pick one tool and stick with it. If you do change tools, you should redo all historical assessments in the new tool, as results from different tools aren’t comparable.

Practical questions

These questions determine whether the tool is right for you and your farm.

  • Does my buyer/supply chain require a specific tool?
    • Check if your supply chain specifies a particular tool
  • Does it cover everything my farm produces?
    • Some tools cover all crops and livestock species, while others focus on a specific sector
  • What levels of footprint are provided?
    • Tools may provide footprinting at whole-farm, enterprise, production-system and product levels
  • How easy is the data-entry process – do I need support?
    • Often, you can enter your own data and written guidance is provided. Some tools require more detailed information, while others have a simplified option. Some tools also offer to help with the data entry, often for a fee
  • How much does it cost?
    • There are several free options available. These may be more basic, with other features available (such as assistance or benchmarking) for a cost
  • Can I make comparisons?
    • This could be ‘what if’ scenarios, reports over time, or benchmarking. See if this service is provided – and if it costs extra. Benchmarks might be against national averages, against a group, or against your farm’s theoretical best result
  • Does it include carbon sequestration?
    • Some tools also include carbon sequestration – this could be biomass sequestration, such as woodland and hedgerows, or sequestration of soil carbon

Technical questions

These questions help ensure you have the best data possible – and will be important to those who might want to see the data as proof of your footprint. 

  • Does it adhere to a set standard?
    • A calculator should be based on robust science and data. Adherence to a set standard is a quick way to show this. Officially recognised standards for carbon footprinting exist, but not all calculators use them. These standards include ISO14064 and ISO14067, the Greenhouse Gas Protocol, and SBTi FLAG guidance. The PAS 2050:2011 standard has been previously recommended, but this is now considered outdated per Defra’s calculator harmonisation work (published early 2024) Additionally, the IPCC has set methodology to account for greenhouse gas emissions, and some calculators follow this methodology. This could be either at tier 1 (basic) or tier 2 (intermediate)
  • How does it cover methane and nitrous oxide emissions?
    • These are the two main greenhouse gases from agriculture. In order to be comparable with carbon dioxide emissions, the amounts are routinely calculated as carbon dioxide equivalents (CO2e) using the global warming potential over 100 years. Some tools are now dual reporting, using GWP* for methane to better take account of its relatively short-lived nature in the atmosphere
  • Does it regularly update and improve?
    • A static tool that doesn’t get updated doesn’t just miss out on gaining new features but also may not reflect the latest scientific data, e.g. on emissions factors
  • Does it link to assessments of other environmental impacts?
    • A number of the tools are also linking to water and biodiversity metrics

Where to start looking

These are some of the companies with popular carbon tools, listed alphabetically: Agrecalc, Cool Farm Alliance, Farm Carbon Toolkit, and Trinity Agtech.

As a starting point, a comparison of these tools is provided below. There are also numerous other tools available. It is worth taking the time to explore the options to identify the tool that will best suit your needs.

Table 1. Comparison of three popular carbon calculators. Last updated April 2024.

Company Agrecalc Cool farm alliance Farm carbon toolkit Trinity Agtech
Tool Agrecalc Cool farm tool Farm carbon calculator Sandy
Website  https://calculator.
Audience - farmer or supply chain Farmer & supply chain Farmer & supply chain Farmer & supply chain Farmer & supply chain
Cost Free for individual farmers, at their basic tier.

Additional features such as comparisons available in paid tiers.
Free for individual farmers for non-commercial use Free for individual farmers non-commercial use. Annual licence fee from £618
Sectors covered All AHDB sectors covered, plus potatoes, poultry, some horticulture, and others. All AHDB sectors covered*, plus potatoes, poultry, some horticulture, and others.

*CFT have advised against using their module for non-cattle livestock until v3.0 is released (est Q4 2024)
All AHDB sectors covered, plus potatoes, poultry, some horticulture, and others. All AHDB sectors covered, plus potatoes, horticulture, poultry, other livestock, permanent grassland,peat, and others
Level of footprint Whole farm, enterprise and product Product only Whole farm, can be broken down to products Whole farm, enterprise, field, crop, and variety level
Data input Online, input by farmer.

Option to use consultants or
data collection business.
Printable data collection sheets available.
Online, input by farmer.

Option to use consultants or
data collection business.
Online, input by farmer.

Option to use consultants or
data collection business.
Excel spreadsheet for bringing data together is available.
Company offer training services for a cost.
Online, input by farmer. API links to Farm Management Software systems.

Option to use consultants.
Online coaching and 'onboarding support' provided, amount dependent on package bought
Ease of input Detailed information required, but still reported as easy to use - if data is available. Update to Agrecalc Cloud includes improved user interface. Reportedly easy to use. Advanced packages allow connection to other apps to transfer data.  Reportedly easy to use, with real time visuals Easy data input. Data can be added directly, via Excel templates, or link to Gatekeeper and Muddy Boots software. 
Benchmark comparisons available ”General industry benchmarks” available in free version. Group and more detailed industry benchmarking available in paid tiers  Not currently, but was scheduled for spring 2024 Basic benchmarks against national averages, with test version of more detailed benchmarking available to all since 31/10/23 "Scientific Benchmarking" functionality compares farm's current vs possible best practice. Central reporting allows group benchmarking. 
Carbon sequestration options Yes - soil, woodland, hedgerows and biochar (tier 1) Yes for crop footprints - trees, land use change and soil (via management practices) (tier 1) Yes - soil, land use/management & biomass (woodland, hedgerows, perennials) (tier 1) Yes - Soil by type/use, woodland, hedgerows, agroforestry, biochar and perennial crops (Mostly tier 2-3 & the Woodland Carbon Code)
Standards & methodologies IPCC methodology: “Mostly tier 2”

Alignment to standards: Version 1 aligns to PAS 2050:2011; Agrecalc Cloud is preparing for ISO 14064 & 14067 certification, and aims to align to GHG protocol and SBTi FLAG during 2024.
IPCC methodology: Mix of tier 1 and tier 2

Alignment to standards: not certified, “seeks to be aligned with various standards and protocols” 
IPCC methodology: Tiers 1 and 2

Alignment to standards: not certified, is “actively considering alignment with international standards such as ISO 14064 and the GHG Protocol, as well as land-sector based guidance from FLAG.”
IPCC methodology: Tier 2, with tier 3 where improved accuracy is available and tier 1 where tier 2's not seen to add to accuracy. 

Alignment to standards: Certified for ISO 14067 & 14064:2. Aligned to a range of other standards including SBTi FLAG, GHG Product Life Cycle Accounting and Reporting Standard, GHG Protocol Land Sector and Removals Guidance, BSI Natural Capital Accounting standard BS 8632:2021, and others
Greenhouse gas metric used GWP100, future releases to include GWP*  GWP100 GWP100, Option to discuss GWP* in a consultation.
intention is to show both global warming potential (GWP) and GWP* in the future
GWP100 and GWP*
Frequency of updates
(information as of Jan 2024)
A few updates and improvements each year with a large upgrade (Agrecalc Cloud) released in July 2023 to paid users and those in government support schemes Small bug fixes and improvements are continual, with large-scale updates every 1-2 years (CFT 2.0 launched in April 2023, CFT 3.0 is currently estimated for Q4 2024) Aim to update at least twice a year. Last big updates were September 2023 and April 2024 Monthly updates
Other areas assessed - Food waste, water use, and biodiversity at whole-farm level Options to include emissions from construction of inventory e.g. farm buildings and machinery. Also has options for some processing from wineries and packhouses. Biodiversity, water protection, agroforestry, soil erosion, natural capital valuation accounts.
Assessment can include AD plant, biochar, soilless controlled environment, buildings, transport, and packhouse.

Additionally, I4Agri have a carbon decision support tool which assesses which of these 4 tools may work best for you based just on your farm and the information you have about it. This comparison tool is based on the carbon programme assessments as they were in April 2023, so may not reflect recent updates to the tools. 

Variation in results

Currently, there is not a lot of harmony between calculators – even those following the same standards will have subtle variations in their calculations which lead to different results. In 2023, Defra commissioned a report to identify where the main differences between results occurred and how these could be improved. The calculators used were: Agrecalc (from Agrecalc Ltd), Cool Farm Tool (the Cool Farm Alliance), Carbon Footprint tool (Eggcase Ltd), Farm Carbon Calculator (Farm Carbon Toolkit), Sandy (Trinity Agtech’s natural capital navigator) and The Farm Carbon Calculator (SolAgro)

Read AHDB's summary of the report

Access the full report on the Defra website

As of June 2024, Agrecalc, Cool Farm Alliance and Farm Carbon Toolkit have announced they will be working together to "harmonise the methodologies used in calculating the greenhouse gas (GHG) emissions from agriculture". 

Additionally, prior to this, three companies published independent responses to the report with regards to their tools: 

What does this mean for farmers?

Due to the variation in calculations, results between different calculators can’t be compared. Even once harmonised, the tools will likely still have some differences. Therefore, to build a multi-year baseline, or show changes over time, all your farm’s footprints must be in the same tool.

Further information

See what you could get from a carbon audit and action plan

Find further information on harmonising carbon calculators

Read historic AHDB advice for cereals and oilseeds