When businesses begin their carbon accounting journey, one of the first decisions they face is surprisingly difficult:

Should we manage our carbon emissions using spreadsheets, or invest in dedicated carbon accounting software?

For many SMEs, spreadsheets feel like the natural starting point. They’re familiar, flexible, and free. But as reporting expectations grow — especially with frameworks such as the GHG Protocol, EcoVadis, CSRD, and the NHS Evergreen Sustainable Supplier Assessment — spreadsheets quickly become a bottleneck.

This guide breaks down the pros and cons of both approaches, highlights when each makes sense, and explains how organisations can scale their climate reporting without unnecessary complexity or cost.

Spreadsheets: A Simple Starting Point for Early-Stage Carbon Accounting

Spreadsheets are often the first step for businesses calculating a carbon footprint. And for early-stage reporting, they’re perfectly valid.

The advantages of spreadsheets

1. Free and easy to access

Excel and Google Sheets allow teams to start collecting data immediately. Useful if you’re building your first emissions baseline (see our guide on creating your first sustainability report).

2. Highly flexible

You can customise structure, formulas, and methodology however you like.

3. Good for simple Scope 1 and 2 calculations

Energy, fuel and electricity consumption can be handled neatly in a spreadsheet.

4. Helps teams learn the fundamentals

You’ll understand how emissions factors work, how to organise data, and where your emissions come from.

Spreadsheets have clear limitations

1. High risk of manual error

Incorrect formulas and inconsistent assumptions can derail your calculations — a known problem highlighted in the European Financial Reporting Advisory Group (EFRAG) guidance.

2. Time-consuming

Manually gathering energy, travel, waste and procurement data takes hours or days.

3. Not scalable

Once you begin calculating Scope 3 emissions, especially categories like Purchased Goods & Services, spreadsheets fall apart. (See our full guide: Calculating your Scope 3 emissions.)

4. No audit trail

Frameworks like CSRD require transparent, traceable methodology — something spreadsheets can't provide.

5. Difficult to maintain year-on-year

Version control becomes messy, especially once multiple teams contribute data.

Carbon Accounting Software: Automation, Accuracy and Scalability

Carbon accounting software is designed to reduce manual work, eliminate errors and support compliance across frameworks such as GHG Protocol, CDP, SBTi, and EcoVadis.

Key advantages of software

1. Automated emissions calculations

Software updates emission factors (such as DEFRA, EPA and IEA) automatically — no manual updates required.

2. Streamlined data collection

Most platforms allow teams and suppliers to upload information directly, helping with Scope 3 categories like waste, commuting and procurement.

3. Strong audit trail

Perfect for CSRD, SBTi or NHS Evergreen submissions.

4. Designed for Scope 3

Scope 3 often represents up to 90% of total emissions, and software simplifies supplier engagement, spend-based calculations and activity-based data collection.

5. Generates reduction plans

Software can support science-aligned pathways, helping you develop targets consistent with the Science Based Targets initiative.

6. Significant time savings

Automation reduces reporting workloads from days to minutes.

Limitations of software

1. Cost

Platforms range from affordable SME tools to expensive enterprise systems.

2. Requires onboarding and training

Teams need time to understand workflows and dashboards.

3. Potential overkill for tiny organisations

If you're only producing a one-off footprint, spreadsheets may still be enough.

When Spreadsheets Make Sense — and When They Don’t

Spreadsheets work well when:

You’re calculating your emissions for the first time

You have simple Scope 1 and 2 data

You’re building your first sustainability report

You don’t need supplier-level Scope 3 data

You’re not yet reporting to regulated frameworks

Carbon accounting software is the better choice when:

Reporting annually or for multiple stakeholders

You must calculate detailed Scope 3 emissions

You need audit-ready documentation

You are aiming for NHS Evergreen, EcoVadis, CSRD, or SBTi alignment

Supplier engagement is required

Your footprint becomes too complex for manual management

If your organisation is scaling, operating across multiple sites, or part of a regulated supply chain, software will save time, increase accuracy and reduce risk.

The Hybrid Approach: Start Simple, Then Scale with Software

For many SMEs, the best strategy looks like this:

Year 1:

Use spreadsheets to perform your baseline footprint and understand where emissions come from.

Year 2:

When reporting becomes recurring, adopt a software platform to automate calculations and streamline data gathering.

Year 3+:

Use software for supplier engagement, reduction planning, and scenario modelling to support long-term decarbonisation.

This approach balances cost, accuracy, and operational readiness.

FAQ

Do SMEs need carbon accounting software from day one?

No. Spreadsheets are fine for early-stage reporting. Software becomes essential when Scope 3, auditability, or regulatory compliance are required.

Is software more accurate than spreadsheets?

Yes. Software uses updated emission factors, automated formulas and transparent methodologies.

What’s the biggest problem with spreadsheets?

Manual error and poor auditability — especially problematic for CSRD or NHS Evergreen assessments.

Can I produce a compliant carbon report using spreadsheets?

You can, but it’s far more time-consuming and difficult to defend.

When is it time to switch to software?

When reporting becomes annual, multi-site, supplier-dependent or aligned to external standards such as EcoVadis or SBTi.