# When should a small company move carbon accounting from Excel to software?

Canonical: https://senseible.earth/answers/excel-or-carbon-accounting-software

Stay in Excel while you have one site, a few fuel and electricity sources, one person keeping the sheet and nobody checking the evidence. Move when a buyer, lender or auditor wants to trace figures to documents, when you add sites or Scope 3 supplier lines, or when more than one person edits the numbers.

## When Excel is enough

A well-kept sheet that names each factor and links each row to a scanned bill meets the GHG Protocol's principles of accuracy, consistency and transparency.

- One site, a monthly electricity bill and a few fuel purchases: twenty to forty rows a year.
- The figure is for your own planning, not for a buyer, bank or regulator.
- One careful person owns the sheet and the factors are written next to each row with their source.

## Signs you have outgrown it

- Someone outside the company will check the numbers and asks where each one came from.
- You add a second plant or warehouse, and bills arrive from more than one discom or fuel supplier.
- Scope 3 enters: hundreds of supplier invoice lines that need a category, a unit and a factor each.
- The same invoice could be entered twice by two people, and nothing would stop it.
- Factors change between years and you need old reports to keep their old factors.

## What any tool should do that a sheet does not

These are what an ISO 14064-3 verifier looks for in an evidence trail. If software does not do them, it is a prettier spreadsheet.

1. Keep the source document attached to every figure, with the page or line it came from.
2. Stop the same file being counted twice.
3. Record which factor and version was applied, so a past figure can be recomputed.
4. Show what changed, by whom and when.

## A middle path

Many small companies keep Excel for planning and targets, and use software only to turn bills and invoices into a traceable record. That way the sheet stays simple and the evidence sits in one place.

## What Senseible does here

Senseible reads bills and invoices into line items with the source page, the factor applied and a SHA-256 fingerprint per file, so the same file is not counted twice. For a handful of rows a year with no outside checker, a well-kept spreadsheet does the job and Senseible adds little.

- [DIY or consultant for carbon accounting](https://senseible.earth/climate-intelligence/diy-vs-consultant-carbon-accounting-msme-decision-framework)
- [Can carbon accounting be fully automated](https://senseible.earth/answers/can-carbon-accounting-be-fully-automated)
- [Auditors and Senseible reports](https://senseible.earth/answers/auditors-and-senseible-reports)

Sources: [GHG Protocol Corporate Accounting and Reporting Standard (2004), chapter 1, accounting principles](https://ghgprotocol.org/corporate-standard), [ISO 14064-3:2019, Validation and verification of GHG statements](https://www.iso.org)

Last reviewed 2026-10-15.