Carbon Footprint Calculator
Estimate Scope 1, 2 and 3 GHG emissions in line with the GHG Protocol, structured for CSRD/ESRS E1, UK SECR, California SB253/261 and ISSB IFRS S2 disclosure — brought to you by The ESG Institute.
Download the user guide (PDF)Organization & reporting setup
Filled once, used across both the quick estimate and the detailed calculator.
Quick Estimate
A directional number based on typical emissions intensity for organizations of your size and sector. Good for a first read — not a substitute for the detailed calculator when you need audit-ready figures.
Scope 1 — Direct emissions
Fuel burned on-site or in owned/leased vehicles, plus refrigerant leaks from owned equipment.
| Facility / asset | Fuel / source (Select) | Quantity | Unit | tCO2e | Data quality (Select) ? |
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Get your PDF report
Enter your details and we'll generate your GHG summary report immediately — no waiting, no separate email required.
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About this carbon footprint calculator
The ESG Institute built this calculator for businesses that need a greenhouse gas number and don't have a sustainability team to produce one. It runs in your browser, costs nothing, and works in ten languages: English, Spanish, French, German, Italian, Portuguese, Chinese, Vietnamese, Malay and Russian.
What it measures
The tool follows the GHG Protocol Corporate Standard and covers all three emission scopes. Scope 1 captures fuel you burn on site and in vehicles you own or lease, plus refrigerant leaks from your own equipment. Scope 2 covers the electricity, heat and steam you buy, reported both location-based and market-based as the GHG Protocol requires. Scope 3 covers your value chain, with full calculators for business travel, employee commuting, purchased goods and services, and waste, plus a screening step across all fifteen Scope 3 categories so nothing gets quietly left out.
You can work in either of two modes. The Quick Estimate gives you an order-of-magnitude figure in about two minutes using sector benchmarks. The Detailed Calculator takes line-item activity data and produces figures you can put in front of an auditor, tagging every row by data quality so you can see how much of your inventory rests on measured data rather than estimates.
Which reporting frameworks it supports
Choose your target framework in the setup panel and the results and PDF report adjust their footnotes to match. The calculator supports the EU Corporate Sustainability Reporting Directive (CSRD) and ESRS E1, the UK's Streamlined Energy and Carbon Reporting (SECR), California SB253 and SB261, and ISSB IFRS S2. The underlying calculation follows the GHG Protocol in every case, because all four regimes defer to it for emissions methodology.
Where the emission factors come from
Every factor carries a source label you can see when you select it. UK electricity, natural gas and vehicle factors come from the 2025 DESNZ/DEFRA conversion factors. US grid figures come from EPA eGRID2023, France from RTE, and India from the Central Electricity Authority's CO2 Baseline Database. Refrigerant global warming potentials use IPCC AR5. A full sources and methodology table sits inside the tool, including a note on which factors we verified independently and which remain indicative.
Who it's for
Small and mid-sized businesses building their first inventory, sustainability managers who need a defensible baseline, and finance teams working towards a disclosure deadline. The output is an estimate rather than assured data, so anything going into a regulatory or investor filing should be verified by a qualified professional first.
If you want help turning your figures into a credible disclosure, our advisory team works with businesses at every stage. If you would rather build the capability in house, our Diploma in GHG Accounting, Verification & Validation covers the methodology this calculator applies. You can also download the user guide before you start.