Online calculators will give you a carbon footprint in two minutes. The problem is that the number won’t survive a customer questionnaire, a BRSR assurance review or a CBAM verification. For a company, a carbon footprint isn’t a quiz result. It’s an inventory you have to be able to defend.
The good news: the method is simple. The hard part is the data. Here’s how to do it properly.
The formula
Every line in a carbon footprint comes from the same calculation:
Emissions = Activity data × Emission factor
- Activity data is what you consumed or did: litres of diesel, kilowatt-hours of electricity, tonnes of coal, kilometres of freight.
- Emission factor turns that activity into greenhouse gas emissions, for example kg of CO2 per litre of diesel.
When the gas isn’t CO2 (methane from waste, or refrigerant leaks), you convert it to CO2 equivalent using a global warming potential (GWP). Pick the GWP values from one IPCC assessment report and use the same set every year.
Add up every line and you have your footprint in tonnes of CO2 equivalent (tCO2e).
Step 1: Set your boundary
Before any numbers, decide what’s in.
Organisational boundary. Which sites, subsidiaries and joint ventures are included? The GHG Protocol lets you use operational control, financial control or equity share. Most Indian companies use operational control. Pick one and write it down.
Operational boundary. Which emissions? This is where the three scopes come in.
Step 2: Understand the three scopes
Scope 1: what you burn. Fuel in boilers, furnaces, DG sets and company vehicles. Process emissions from chemical reactions. Refrigerant leaks from your AC and chillers.
Scope 2: what you buy. Electricity, steam, heat or cooling bought from outside.
Scope 3: everything else in your value chain. Suppliers, freight, business travel, product use and more. Fifteen categories in total. Our guide to Scope 3 emissions covers them.
Start with Scope 1 and 2. They’re what BRSR asks for as essential indicators, what CCTS measures within your gate-to-gate boundary, and what you control directly. Add Scope 3 once they’re solid.
Step 3: Collect activity data
This is the bulk of the work. Common sources:
| Emission source | Where the data usually is |
| Diesel, petrol, LPG, furnace oil | Purchase invoices, fuel logs, stock registers |
| Coal and biomass | Purchase records, weighbridge slips |
| Grid electricity | Monthly electricity bills (kWh, not rupees) |
| Captive solar or open access | Meter readings, open access statements |
| Refrigerants | Maintenance top-up records |
| Process emissions | Production records and material inputs |
Use physical quantities wherever possible. Rupees spent on fuel is a poor proxy, since prices change and a rupee-based figure moves even when emissions don’t.
Step 4: Use the right emission factors for India
This is where many footprints go wrong, usually by using a European or US factor for an Indian site.
Grid electricity. Use the Central Electricity Authority’s CO2 Baseline Database. The latest version (V21.0) puts the all-India weighted average at 0.710 tCO2 per MWh for FY 2024-25. Use the same CEA version for your base year and reporting year so the comparison is fair.
Fuels. IPCC default factors are widely used. For coal, factors based on the actual calorific value of what you burn are more accurate than a default, if you have the lab data.
Refrigerants. Use the GWP of the specific gas, for example R-22, R-410A or R-32. They’re very different.
Record the source and version of every factor. It’s the first thing a verifier asks.
A worked example
A mid-sized manufacturing unit, one year. Illustrative numbers:
Scope 2: electricity 2,000 MWh from the grid × 0.710 tCO2/MWh = 1,420 tCO2e
Scope 1: diesel 50,000 litres × roughly 2.7 kg CO2 per litre = 135,000 kg = 135 tCO2e
Scope 1: refrigerant 20 kg of refrigerant topped up × the gas’s GWP. For a gas with a GWP of about 2,000, that’s 40,000 kg = 40 tCO2e
Total Scope 1 and 2: about 1,595 tCO2e
Two things jump out. Electricity is the biggest source by far, which is typical for Indian manufacturing on the grid. And a small refrigerant leak adds more than you’d guess, because refrigerant GWPs are so high.
Step 5: Turn it into an intensity
A total on its own doesn’t tell you much. If production doubled, emissions probably rose too. Divide by output (tCO2e per tonne of product, or per crore of revenue) to see whether you’re actually getting more efficient.
For obligated entities under CCTS, this intensity is exactly what your target is measured against. We cover the method in GHG emission intensity targets explained.
Where your footprint gets used
- Scope 1 and 2 and intensity are essential indicators under Principle 6. See BRSR reporting explained.
- Obligated entities report gate-to-gate Scope 1 and 2 against their intensity targets.
- Exporters need product-level embedded emissions. Your company footprint is the starting point, not the finished answer. See CBAM default values.
- Customer questionnaires and CDP. Multinational buyers increasingly ask suppliers for this data. If they ask about a specific product rather than your whole company, what they need is a product LCA.
Common mistakes
- Using money spent instead of physical quantities
- Mixing emission factor versions between years
- Leaving out refrigerants and DG sets
- No record of where each number came from
- Counting solar power as zero without evidence of what you actually generated and used
Questions we get asked
How is a company’s carbon footprint calculated? Multiply each activity (fuel burned, electricity bought, and so on) by its emission factor, convert other gases to CO2 equivalent, and add everything up. The result is expressed in tonnes of CO2 equivalent.
What is the carbon footprint formula? Emissions = Activity data × Emission factor. For gases other than CO2, multiply by the gas’s global warming potential to get CO2 equivalent.
What emission factor should I use for electricity in India? Use the Central Electricity Authority’s CO2 Baseline Database. Version 21.0 gives an all-India weighted average of 0.710 tCO2 per MWh for FY 2024-25.
What is the difference between Scope 1, 2 and 3? Scope 1 is direct emissions from sources you own or control. Scope 2 is emissions from electricity, steam and heat you buy. Scope 3 is all other emissions in your value chain.
Can I use an online carbon footprint calculator for my company? It’s fine for a rough first estimate. For BRSR, CCTS, CBAM or customer reporting, you need a documented inventory with sourced emission factors that can stand up to verification.
Bilancia Consulting is an Ahmedabad based sustainability and ESG advisory firm. We build GHG inventories for Indian companies that hold up to BRSR assurance, CCTS verification and customer audits, and we run capacity building so your team can maintain them. If you need a footprint that will stand up to questions, a short call is the fastest place to start.
Call +91-9510144494 or email general@bilanciaconsulting.co.in