Top 5 GHG Emissions Calculation Tools 2026: Comparison for Vietnam

In 2026, the five GHG emissions calculation tools worth considering for companies in Vietnam are Persefoni, Microsoft Sustainability Manager, Mecarbon, XCarbon and EcoCheck. The two international platforms are strong on Scope 3 and global reporting frameworks but do not publish a report template for Vietnam's Decree 06/2022/ND-CP. The three Vietnamese tools offer local support and target the Decree 06 report format; of these, EcoCheck is the only one with public pricing, a CBAM embedded-emissions calculator and an AI assistant connection. The free GHG Protocol spreadsheets remain a sensible starting point for small facilities.

This article was fully rewritten in October 2026, replacing our 2024 comparison. Every vendor claim was checked against the vendor's own website on 9 October 2026, with links so you can verify them yourself.

Disclosure: EcoCheck is our product. We have tried to keep this comparison fair: we only state what each vendor publishes, mark gaps as "not stated", and list EcoCheck's limits too. If you are a vendor and something is wrong, please contact us and we will update it.

What do Vietnamese companies need from an emissions tool in 2026?

Needs in 2026 are very different from 2024 because of three changes:

• A larger mandatory list: Decision 42/2026/QD-TTg (effective 25 September 2026) requires 2,441 facilities to conduct a GHG inventory, with facility reports due before 31 March 2027 (see Decision 42/2026/QD-TTg). Reports must follow the templates of Decree 06/2022/ND-CP (amended by Decree 119/2025/ND-CP) and sector-specific methods.
• CBAM's definitive period started on 1 January 2026: EU importers must declare embedded emissions of iron and steel, aluminium, cement, fertilisers, hydrogen and electricity. If a Vietnamese exporter has no actual data, the importer must use default values, which are usually higher.
• International buyers ask for Scope 3: FDI companies and export suppliers need data under the GHG Protocol and ISO 14064-1, sometimes across all 15 Scope 3 categories.

So a "good" tool for a Vietnamese company must not only calculate correctly; it must also produce the report filed with the authorities, use Vietnamese emission factors, and come with people who can help during verification.

Comparison table: 5 GHG emissions calculation tools

The table summarises 7 criteria. "Not stated" means the vendor's official page did not mention it on the date checked; it does not prove the feature is missing.

Sources: official pages of Persefoni, Microsoft, MECIE, OMPQI, EcoCheck; checked 9 October 2026. EcoCheck prices exclude VAT.

Figure 1: Matrix comparing 5 GHG emissions tools in 2026 on Decree 06 templates, Vietnamese factors, Scope 3, CBAM, AI, pricing and support

Tool by tool: who is it for, and what are the limits?

1. Persefoni

A US carbon accounting platform for large enterprises and financial institutions. The Pro plan is free with no credit card and covers a Scope 1, 2 and 3 footprint (all 15 Scope 3 categories), a sustainability report builder and a GPT-based Copilot. The Advanced plan (unlimited users, SOC 2) is priced on request.

• Good fit: subsidiaries of foreign groups, companies reporting to CDP, CSRD or ISSB.
• Limits: Pro is limited to one user and excludes detailed GHG Metrics reports; the site does not mention Decree 06 templates, Vietnamese factors or support in Vietnam.

2. Microsoft Sustainability Manager

Part of the Microsoft ecosystem, managing carbon, water and waste data. List prices: Essentials US$4,000 per tenant per month (Scopes 1, 2 and several Scope 3 categories), Premium US$12,000 per tenant per month (all of Scope 3, Copilot in Preview). Some features require Azure, Microsoft 365 or Power BI licences.

• Good fit: groups already on Dynamics 365 and Azure with an IT team to deploy it.
• Limits: expensive for mid-sized companies; the product page does not mention Vietnamese, Decree 06 or CBAM.

3. Mecarbon (MECIE)

Online software from MECIE Vietnam. According to its product page, Mecarbon can print and export reports in Form 04, Appendix II of Decree 06/2022/ND-CP, combines Scope 1, 2 and 3 sources, and can link to continuous monitoring systems.

• Good fit: facilities that must file with the authorities and want a consultant bundled with the software.
• Limits: no public pricing; the page does not mention CBAM, AI or the specific factor source used by the software.

4. XCarbon (OMPQI)

Developed by OMMANIX and distributed by OMPQI. The product page says XCarbon is "designed to meet" ISO 14064-1 and Decree 06/2022/ND-CP, with a factor hub that suggests factors by priority from Decision 2626, IPCC, GHG Protocol and EPA, sector-based emission ledgers and dashboards by branch and plant.

• Good fit: companies with many branches or plants that track data periodically.
• Limits: no public pricing; Scope 3 and AI are not mentioned; CBAM is a separate consulting service, not a software feature.

5. EcoCheck

A GHG inventory and EU CBAM platform from BeevR Technology (Vietnam). It covers ISO 14064-1 and Decree 06/2022 reports, Scopes 1 to 3 including 15 Scope 3 categories, Vietnamese emission factors and embedded emissions (SEE) for CBAM. It also works inside ChatGPT and Claude: EcoCheck has been listed in the Claude Connectors directory since 9 October 2026; workspace owners set AI permissions and every command is logged. Public pricing on the EcoCheck pricing page: Basic free, Pro VND 4,950,000/month, Pro+ VND 10,950,000/month, Advanced custom.

• Good fit: facilities on the Decision 42/2026 list, exporters facing CBAM, suppliers that must give customers Scope 3 data.
• Limits: Basic allows one member and one organisation and has no regulatory report; CBAM starts at Pro; GHG consultants are a paid option on Pro and Pro+; reduction targets and plan tracking are only in Advanced. In ChatGPT the EcoCheck app is still under OpenAI review; for now it is added by URL via Settings › Plugins (desktop app) or Developer mode (web). EcoCheck is also a much smaller vendor than Persefoni or Microsoft.

An AI assistant answering emissions by scope from EcoCheck inventory data

Are there free tools?

Yes. The GHG Protocol offers free Excel calculation tools by source type (stationary combustion, mobile sources, refrigeration, GWP values) with guidance documents. They are a good way to learn the method. However, the older all-in-one "GHG Emissions Calculation Tool" is no longer available, and the Scope 3 Evaluator page says access was only maintained until 30 August 2023. Spreadsheets have no Decree 06 template, no built-in Vietnamese factors and no record of who changed what.

Some software also has free plans: Persefoni Pro and EcoCheck Basic. To decide between doing it in Excel, hiring a consultant or using software, see our comparison of the three approaches.

If you only need a quick Scope 1 and 2 calculation by hand, our Scope 1 and 2 emissions calculator guide has the formulas and factors.

Checklist for choosing a GHG emissions tool

1. Is your facility on the mandatory list? Check with the GHG inventory obligation checker. If yes, prioritise tools that produce the Decree 06 report.
2. Ask for a sample report in the exact format filed with the provincial People's Committee, not just a nice dashboard.
3. Ask about emission factors: which year's Vietnam grid factor, which document the fuel factors come from, and whether sources are cited in the report.
4. Scope: Scopes 1 and 2 only for the government report, or Scope 3 for customers too.
5. CBAM: if you export steel, aluminium, cement or fertiliser to the EU, you need SEE calculation by CN code and data export for importers.
6. Several data entry users: check permissions, change logs, and user and facility limits per plan.
7. AI: if you use an AI assistant, who can write data, is there a log, and where is data stored.
8. Total cost over two reporting periods: software, experts and data integration. Compare with the cost of hiring an inventory service.
9. Support during verification: who explains the report to the authority if corrections are requested.
10. Data export: can you download all your data if you switch vendors.

Next step: try EcoCheck Basic for free, or see how to use EcoCheck in ChatGPT and Claude. If this is your first inventory, read the 2026 GHG inventory process before choosing a tool.

Frequently asked questions

What is the best GHG inventory software in 2026?

No tool is best for every company. Facilities that must report under Decree 06 should pick a tool with Vietnamese templates and factors (Mecarbon, XCarbon, EcoCheck). Subsidiaries of foreign groups that report under CSRD or ISSB may be better served by Persefoni or Microsoft.

Is there free GHG emissions calculation software?

Yes: the GHG Protocol Excel tools, Persefoni's Pro plan (one user) and EcoCheck's Basic plan. Free plans usually limit users or reporting features.

Is Excel enough to file a Decree 06 inventory report?

The law does not require software. Excel can be enough if the facility has few sources and the preparer understands the method and follows the report template. The risks are formula errors, outdated factors and difficulty explaining figures during verification.

Is SimaPro a GHG inventory tool?

SimaPro describes itself as life cycle assessment (LCA) software, suited to product carbon footprints. A facility-level inventory under Decree 06 is a different task, so SimaPro is not included in this comparison.

Which software can calculate CBAM?

Of the five tools above, only EcoCheck publishes an in-software embedded emissions (SEE) calculation for CBAM. The Persefoni, Microsoft, Mecarbon and XCarbon pages did not mention it as of 9 October 2026.

Is it safe to use AI such as ChatGPT for a GHG inventory?

AI should call verified calculation tools rather than calculate on its own. With EcoCheck, the AI calls EcoCheck's tools, the workspace owner decides whether AI can read or write, and every command is logged. Results still need review by a qualified person before filing.