Becoming a B Corp is more than a badge—it’s a commitment to operating as a force for good. But before you can proudly display that coveted “B,” you’ll need to get a firm handle on your company’s carbon footprint.

Why?

Because B Lab places significant emphasis on your environmental impact and expects you to measure, manage, and reduce your carbon emissions using credible methodology.

In this guide, you'll learn exactly how to measure your carbon footprint step-by-step for B Corp Certification, the tools you’ll need, and common mistakes to avoid.

Step 1: Establish Your Reporting Boundaries

Start by defining what parts of your business you’ll include in your emissions assessment. B Corp expects clarity and consistency here.

You need to define two things:

1. Organisational boundaries

Choose whether you use:

Operational control (recommended)

Financial control

Equity share

Most companies select operational control because it's straightforward and aligns well with B Lab's expectations.

2. Reporting boundaries (Scopes 1, 2, and 3)

Use the Greenhouse Gas Protocol, the global standard for emissions reporting.

Scope 1: Direct fuel use (vehicles, gas boilers, generators)

Scope 2: Purchased electricity, steam, heat, or cooling

Scope 3: All indirect value-chain emissions—often the largest category

Step 2: Gather the Right Activity Data

Activity data is the raw input you convert into emissions. Think of it as fuel receipts, electricity bills, or business-travel mileage.

Collect data for:

Electricity use (kWh)

Office heating (gas, oil, LPG)

Company vehicles (litres of fuel or miles/km travelled)

Business travel (flight distance, rail, taxi)

Waste production (kg or tonnes)

Purchased goods/services

Home working (yes, this counts!)

Step 3: Convert Activity Data Into Carbon Emissions

To calculate your emissions, multiply each data point by an emissions factor.

Formula:

Activity Data × Emissions Factor = CO₂e Emissions

Use government-approved emissions factors, such as:

UK DEFRA/BEIS factors

EPA emissions factors (US)

IEA electricity factors

Local grid intensity data

Step 4: Sum Up Your Scopes and Create Your Carbon Baseline

Once you’ve calculated emissions for each category, roll everything up into a carbon baseline.

Your baseline should show:

Total emissions by scope

Total emissions by category

Clear methodology

Data sources

Any assumptions or estimates

This baseline becomes your reference point for B Corp Certification. It also helps set reduction goals later.

Step 5: Identify Reduction Opportunities

B Corp isn’t just about reporting—the certification expects meaningful plans to improve your environmental impact.

Look for opportunities such as:

Switching to 100% renewable electricity

Electrifying fleet vehicles

Improving insulation or HVAC efficiency

Reducing waste

Switching to low-carbon suppliers

Encouraging sustainable commuting

Engaging employees in climate education

Step 6: Set Targets and Create an Emissions-Reduction Plan

A credible reduction plan includes:

Clear annual reduction targets

Timeline for execution

Owners for each action

Budget considerations

Planned technology investments

Supplier engagement strategy

B Lab looks for structured, realistic, and measurable commitments.

Step 7: Use Your Results to Complete the B Impact Assessment (BIA)

Now that you have your carbon footprint calculated and your action plan ready, you can provide:

Your emissions data

Documentation of your methodology

Evidence of reduction initiatives

Progress against targets

Any third-party verification (optional but valuable)

Companies with credible footprints often gain a significant boost in their BIA score—especially under “Environmental Management.”

Recommended Tools for Carbon Footprint Measurement

Emerald Power (for automated carbon data collection & investor reporting)

If you want a streamlined solution for gathering emissions data from your company—or your entire portfolio—Emerald Power helps automate data collection, calculate emissions across Scopes 1–3, and generate B Corp-ready reports.

What to avoid in your B Corp Carbon Footprint Report.

Only measuring Scope 1 & 2 (B Corp expects Scope 3 for most SMEs)

Using spend-based calculations when activity data is available

Relying on annual financial reports instead of real usage data

Ignoring remote-work emissions

Not clearly documenting your methodology

FAQ: Measuring Your Carbon Footprint for B Corp Certification

1. Do I need to measure all three scopes for B Corp?

Not always—but most companies do. If Scope 3 emissions are material (which they usually are), you’re expected to measure and report them.

2. How far back do I need to go?

B Corp only requires a recent reporting year, but having multiple years of data strengthens your score.

3. Do I need third-party verification?

It’s optional, but verification can give you extra credibility and help avoid errors.

4. How long does carbon measurement take?

Small companies can complete their footprint in 2–6 weeks depending on data availability. Using a platform can significantly shorten this timeline.

5. Can Emerald Power help with B Corp emissions reporting?

Yes—Emerald Power automates data collection, calculates emissions across all scopes, and generates reporting output aligned with BIA requirements.

Final Thoughts

Measuring your carbon footprint is one of the most impactful steps you can take on your journey to B Corp Certification. With the right data, tools, and methodology in place, you’ll not only increase your BIA score—you’ll build a more responsible, resilient, and future-ready company.