kWh to CO₂ Calculator
Convert your electricity use in kilowatt-hours (kWh) into estimated carbon emissions (kg CO₂e). Enter a number to see the result and how it's worked out.
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How it's calculated
The calculation is a single multiplication, using the grid factor for the region you select:
kg CO₂e = electricity (kWh) × grid factor (kg CO₂e/kWh)
Grid intensity varies a lot by region and falls year on year, so you can pick your grid. Factors used:
- World average: 0.458 kg CO₂e per kWh — Ember (2026), 2025 lifecycle grid intensity via Our World in Data
- Zambia: 0.12 kg CO₂e per kWh — Ember (2026), Zambia 2025 lifecycle grid intensity via Our World in Data
- United States: 0.384 kg CO₂e per kWh — Ember (2026), US 2025 lifecycle grid intensity via Our World in Data
- United Kingdom: 0.217 kg CO₂e per kWh — Ember (2026), UK 2025 lifecycle grid intensity via Our World in Data
- European Union (EU-27): 0.21 kg CO₂e per kWh — Ember (2026), EU-27 2025 lifecycle grid intensity via Our World in Data
Accuracy and limitations
- Published grid factors are annual lifecycle averages. Hourly, supplier-specific and local grid intensity can differ materially.
- The 2025 factors include power-station, upstream supply-chain and infrastructure emissions. Do not compare them directly with a generation-only factor without aligning boundaries.
- For formal reporting, use the factor, reporting year and market-based or location-based method required by the relevant standard. The custom option accepts a utility-specific factor.
Frequently asked questions
How do you convert kWh to CO₂?
Multiply the electricity used (in kWh) by an emission factor expressed in kg CO₂e per kWh. The factor reflects how your local grid generates electricity, so a cleaner grid gives a lower result for the same usage.
Why does the emission factor vary by country?
A grid powered mostly by renewables or nuclear emits far less per kWh than one relying on coal or gas. Use the published factor for your country or region for an accurate figure.
Is this the same as my electricity bill’s carbon figure?
It is an estimate using a grid-average factor. Your supplier may use a tariff-specific (e.g. 100% renewable) factor, which can differ from the grid average used here.