Carbon Footprint Calculator

Estimate annual carbon emissions from electricity, petrol and other monthly sources. Enter your own values below to see estimated annual footprint and check the method behind it.

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Change the example values to match your situation.

Your result

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Fill in your inputs and select Calculate.
Your result and breakdown will appear here.

How this calculator works

Sum electricity × grid factor, fuel × combustion factor and other emissions. Multiply the monthly result by 12.

Before you use the result

  • Example factors are editable. Use verified factors for your grid, period and reporting boundary; vehicle manufacture and other unentered sources are excluded.

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What is Carbon Footprint Calculator?

Carbon Footprint Calculator helps you estimate annual carbon emissions from electricity, petrol and other monthly sources.

The main result is estimated annual footprint, with a breakdown of monthly footprint. The formula, example and assumptions below explain how to interpret it.

How to use Carbon Footprint Calculator

Use the example to get familiar with the form, then enter your own figures. Any rates in the example are illustrative. Check the field labels and units before calculating.

  1. Gather monthly electricity (kWh), electricity emissions factor (kg CO₂e/kWh), monthly petrol consumption (litres), petrol emissions factor (kg CO₂/litre) and other monthly emissions (kg CO₂e). Use values from the same situation or reporting period.
  2. Replace the example monthly electricity with your own value, then complete the other fields. Check the displayed units.
  3. Select Calculate and read estimated annual footprint with its result breakdown. Change one input and calculate again to compare a second scenario. Reset restores the original example.
  • Enter monthly electricity in kWh, at least 0. Decimals are accepted.
  • Enter electricity emissions factor in kg CO₂e/kWh, at least 0. Decimals are accepted.
  • Enter monthly petrol consumption in litres, at least 0. Decimals are accepted.
  • Enter petrol emissions factor in kg CO₂/litre, at least 0. Decimals are accepted.
  • Enter other monthly emissions in kg CO₂e, at least 0. Decimals are accepted.

Carbon Footprint Calculator: a worked example

With the inputs below, the result is 3.486 tonnes CO₂e (estimated annual footprint). Follow the example, then replace these illustrative values with your own.

Example inputs and output
Input or outputExample value
Monthly electricity (kWh)250 kWh
Electricity emissions factor (kg CO₂e/kWh)0.7 kg CO₂e/kWh
Monthly petrol consumption (litres)50 litres
Petrol emissions factor (kg CO₂/litre)2.31 kg CO₂/litre
Other monthly emissions (kg CO₂e)0 kg CO₂e
Estimated annual footprint3.486 tonnes CO₂e
Monthly footprint290.5 kg CO₂e

Understanding the Carbon Footprint result

Read estimated annual footprint alongside monthly footprint. These describe different parts of the same calculation.

Displayed results use a readable number of decimal places. When checking a result by hand, keep extra precision until the last step. To compare scenarios, change one input at a time and keep the others fixed.

  • Example Monthly footprint: 290.5 kg CO₂e

Carbon Footprint Calculator: assumptions and common mistakes

A useful estimate starts with the right inputs. Check the following assumptions and limits before applying the result to your situation.

  • Example factors are editable. Use verified factors for your grid, period and reporting boundary; vehicle manufacture and other unentered sources are excluded.
  • Match factors to your location and reporting period. A result covers the sources you entered, not an independently verified full footprint.

For wider guidance, visit GHG Protocol calculation guidance. The formula and scope of this specific tool are stated on this page.

Carbon Footprint Calculator FAQs

What does Carbon Footprint Calculator calculate?

Carbon Footprint Calculator helps you estimate annual carbon emissions from electricity, petrol and other monthly sources. Its main output is estimated annual footprint in tonnes CO₂e.

What inputs do I need for Carbon Footprint Calculator?

You need monthly electricity (kWh), electricity emissions factor (kg CO₂e/kWh), monthly petrol consumption (litres), petrol emissions factor (kg CO₂/litre) and other monthly emissions (kg CO₂e). Use the field labels and units to match your figures to the formula.

Which formula does Carbon Footprint Calculator use?

Sum electricity × grid factor, fuel × combustion factor and other emissions. Multiply the monthly result by 12.

What is a worked example for Carbon Footprint Calculator?

Example inputs: Monthly electricity: 250 kWh; Electricity emissions factor: 0.7 kg CO₂e/kWh; Monthly petrol consumption: 50 litres; Petrol emissions factor: 2.31 kg CO₂/litre. Keep the remaining inputs as shown in the worked-example table. The result is 3.486 tonnes CO₂e (estimated annual footprint).

How should I enter monthly electricity?

Enter monthly electricity in kWh, at least 0. Decimals are accepted.

How do I choose electricity emissions factor?

Enter electricity emissions factor in kg CO₂e/kWh, at least 0. Decimals are accepted. The example uses 0.7 kg CO₂e/kWh; replace it if your circumstances differ.

How should I read estimated annual footprint?

Read estimated annual footprint alongside monthly footprint. These describe different parts of the same calculation.

Why might my Carbon Footprint Calculator result differ from my records?

Example factors are editable. Use verified factors for your grid, period and reporting boundary; vehicle manufacture and other unentered sources are excluded. Differences in entered values, units or rounding can also change the comparison.

Can I compare two scenarios in Carbon Footprint Calculator?

Yes. Note your first estimated annual footprint, change monthly electricity or another input, and select Calculate again. Editing a field clears the old result so it is not mistaken for a new calculation.

Is Carbon Footprint Calculator free, and where are my inputs calculated?

This calculator is free to use without signing in. Its formula runs in your browser; calculator inputs are not sent to a calculation API. The inputs reset to the example values when you reset the form or start a fresh page.