Quick answer
Emissions from electricity = kWh × emission factor. 900 kWh at 0.386 kg CO₂ per kWh emits 347.4 kg of CO₂, or 0.3474 metric tons.
Enter electricity used and the emission factor. The calculator returns kg and metric tons of CO₂.
Related tools: Fuel Emissions Calculator: CO₂ from burning gasoline or diesel. Travel Emissions Calculator: CO₂ from a trip at an emission factor you enter. Greenhouse Gas Conversion Calculator: Convert methane or nitrous oxide to CO₂ equivalent (100-year GWP).
How to use the Electricity Emissions Calculator
- Enter electricity used (kWh) (above 0).
- Enter emission factor (kg CO₂/kWh) (above 0).
- Press Calculate to see the result, and use Reset to start again.
| Input | What to enter | Allowed values |
|---|---|---|
| Electricity used | A number, in kWh | > 0 |
| Emission factor | A number, in kg CO₂/kWh. From your utility or national grid data | > 0 |
Formula and method
Formula
CO₂ = kWh × emission factor
IEEE-754 double precision; shown to the decimals indicated.
Grid emission factors differ by region and year, so use one for your grid.
Worked examples
These examples are verified: each one is an automated test case that the live calculator must reproduce exactly.
Example 1
Inputs: Electricity used = 900; Emission factor = 0.386.
| Result | Value |
|---|---|
| CO₂ emitted | 347.4 kg CO₂ |
| Metric tons | 0.3474 |
Example 2
Inputs: Electricity used = 12000; Emission factor = 0.12.
| Result | Value |
|---|---|
| CO₂ emitted | 1,440 kg CO₂ |
| Metric tons | 1.44 |
Example 3
Inputs: Electricity used = 250; Emission factor = 0.7.
| Result | Value |
|---|---|
| CO₂ emitted | 175 kg CO₂ |
| Metric tons | 0.175 |
The first line is the headline result (cO₂ emitted). Below it the electricity Emissions Calculator lists metric tons, which describe the same case from other angles. IEEE-754 double precision; shown to the decimals indicated.
Factors vary
The factor depends on the region and year, from under 0.05 kg/kWh on hydro-heavy grids to over 0.8 on coal-heavy grids. Use your utility's or national grid factor.
Putting it in context
900 kWh is roughly a month of household use in the US. At this factor, a year (10,800 kWh) emits 4.2 t of CO₂. Switching to renewables lowers the factor.
How the result changes with electricity used
Holding every other input at the first worked example, this table changes only electricity used. It shows how sensitive the answer is to that one value; each row was produced by running this calculator.
| Electricity used | CO₂ emitted | Metric tons |
|---|---|---|
| 450 | 173.7 kg CO₂ | 0.1737 |
| 900 | 347.4 kg CO₂ | 0.3474 |
| 1800 | 694.8 kg CO₂ | 0.6948 |
| 3600 | 1,389.6 kg CO₂ | 1.3896 |
What happens with invalid input
These messages are produced by the calculator itself, so you know what to fix.
- Electricity used: entering "0" shows "Electricity used must be greater than 0." beside that field and no result.
- Emission factor: entering "0" shows "Emission factor must be greater than 0." beside that field and no result.
Choosing between the Electricity Emissions Calculator and similar calculators
Each row shows what a related calculator on this site asks for and what it returns, so you can pick the one that matches your question.
| Calculator | You enter | It returns |
|---|---|---|
| [Fuel Emissions Calculator](/science/fuel-emissions-calculator/) | fuel and fuel burned | CO₂ emitted |
| [Travel Emissions Calculator](/science/travel-emissions-calculator/) | distance traveled and emission factor | CO₂ emitted |
| [Greenhouse Gas Conversion Calculator](/science/greenhouse-gas-conversion-calculator/) | gas and mass emitted | CO₂ equivalent |
| [Dew Point Calculator](/science/dew-point/) | air temperature and relative humidity | Dew point |
| [Acceleration Calculator](/science/acceleration-calculator/) | initial velocity, final velocity and time | Acceleration |
Background: environment and acoustics
Decibels are a logarithmic scale, so sound levels cannot be added arithmetically: two equal sources raise the level by about 3 dB, not double it. Environmental and emissions results depend on the factors behind them (for example the US EPA's equivalency factors), which are averages for a country, fuel and year.
Use the result to compare scenarios rather than as a measured value.
Assumptions and limitations
- Factor is region- and year-specific
If a required value is empty, not a number, or outside its allowed range, the form marks that field with a message and shows no result instead of a misleading number. The automated checks deliberately try invalid entries for electricity used and emission factor to confirm this.
Frequently asked questions
Where do I find my factor?
In your utility's or environmental agency's published data.
Does it include upstream emissions?
Not unless the factor does.
What about natural gas?
Use the carbon footprint calculator.
What does the Electricity Emissions Calculator calculate?
CO₂ from electricity use at an emission factor you enter. It returns CO₂ emitted and Metric tons.
What formula does the Electricity Emissions Calculator use?
CO₂ = kWh × emission factor. Grid emission factors differ by region and year, so use one for your grid.
What do I need to enter in the electricity Emissions Calculator?
You enter Electricity used (kWh) and Emission factor (kg CO₂/kWh).
How is the result rounded or limited?
IEEE-754 double precision; shown to the decimals indicated. Factor is region- and year-specific.
What is an example of a electricity Emissions result?
With electricity used 900 and emission factor 0.386, the cO₂ emitted is 347.4 kg CO₂.
Where does the method come from?
The method follows: Grid emission-factor data from your utility or national inventory.
Related calculators
- Fuel Emissions Calculator — CO₂ from burning gasoline or diesel.
- Travel Emissions Calculator — CO₂ from a trip at an emission factor you enter.
- Greenhouse Gas Conversion Calculator — Convert methane or nitrous oxide to CO₂ equivalent (100-year GWP).
- Dew Point Calculator — Dew point from temperature and relative humidity.
- Acceleration Calculator — Average acceleration from change in velocity over time.
- Mole Calculator — Convert between mass, moles and number of particles.
Sources
- Grid emission-factor data from your utility or national inventory
Content last reviewed 2026-11-04. Formulas and worked examples are checked by automated tests against independently computed values.