Household Emissions Calculator
Calculate the carbon emissions and energy costs from your home electricity and gas usage.
Did this tool work for you?
How to use this calculator
- 1
Enter your monthly electricity usage in kWh (check your energy bill).
- 2
Enter the unit price you pay per kWh for electricity and gas.
- 3
Select your country to use the correct grid emission factor.
- 4
Enter your current renewable energy percentage if applicable.
- 5
Review monthly and annual emissions plus your annual energy bill.
Frequently asked questions
What does the calculator measure?
CO₂ from the electricity and natural gas you enter in kWh, plus their cost from the tariffs you enter. Heating oil, LPG, petrol and other fuels are not included, and gas must be entered in kWh, not in cubic metres or therms.
How is electricity converted to CO₂?
Monthly kWh × the grid factor for the selected country × (1 − renewable % ÷ 100). The factors built into this tool, in kg per kWh, are UK 0.233, US average 0.386, Australia 0.51, Germany 0.38, France 0.052 and global average 0.475. Real factors change year to year, so these are indicative.
How is gas converted?
Monthly gas kWh × 0.202 kg per kWh, with that single figure used in every country. The renewable percentage applies only to electricity, never to gas.
What is the “saving if 100% renewable electricity” line?
It is the electricity emissions still left after your renewable percentage, because those are the kilograms that would disappear at 100%. With the default UK settings and 0% renewable it equals the 81.6 kg electricity line. At 100% renewable it reads 0.0.
What does “cost per tonne of CO₂” mean?
It is annual energy spend divided by annual tonnes, so it shows how many dollars you pay for each tonne your energy use produces. It is not a carbon price. If emissions are zero, such as 100% renewable electricity and no gas, the line shows “n/a (no emissions)”.
Why is the tariff in dollars?
The tariff fields carry a $ sign for display only, and the arithmetic is the same in any currency. Enter your tariff in your own currency and read the cost lines in that currency. Annual cost multiplies the monthly figure by 12.
Does it split the result by person or by appliance?
No. It treats the home as one unit and gives totals for the month and for the year. Negative entries are treated as zero, and a renewable percentage above 100 is capped at 100.
Household emissions calculator for electricity and gas
How to use the household emissions calculator
Use this household emissions calculator to estimate your home's annual carbon footprint from electricity, gas, heating oil, and waste. Enter your monthly usage for each energy source above. The tool calculates total CO₂ emissions and shows the contribution of each source. Free, private, and instant on any device.
How the household emissions calculator works
The household emissions calculator applies grid emission intensity factors and fuel combustion coefficients to your energy consumption inputs to estimate annual CO₂ equivalent emissions. Factors are sourced from DEFRA, EPA, and IEA datasets. All calculations run locally in your browser with no data uploaded.
Two fuels, two factors
Home energy emissions come down to kilowatt-hours multiplied by a carbon factor. Electricity’s factor depends on the grid that supplies it, so the same 350 kWh produces very different totals in different countries. Gas has one factor regardless of location. The calculator applies the grid factor you choose, reduces it by your renewable share, adds gas and then costs both fuels from the tariffs you enter. All factors are figures built into this tool and real values vary by country, year and supplier.
| Region | Electricity factor | Gas factor |
|---|---|---|
| UK | 0.233 | 0.202 |
| US-avg | 0.386 | 0.202 |
| Australia | 0.51 | 0.202 |
| Germany | 0.38 | 0.202 |
| France | 0.052 | 0.202 |
| Global-avg | 0.475 | 0.202 |
Worked example: the default home
350 kWh of electricity at $0.30 and 600 kWh of gas at $0.07 a month, on the UK factor with no renewable share, produce 81.6 kg from electricity and 121.2 kg from gas, 202.8 kg per month and 2.43 tonnes a year. Annual energy cost is $1,764, which works out to $725 per tonne. Gas contributes more here because there are 600 kWh of it against 350 kWh of electricity, and the gas factor of 0.202 is close to the UK grid factor of 0.233.
| Line | Value |
|---|---|
| Electricity | 81.6 kg CO₂ per month |
| Gas | 121.2 kg CO₂ per month |
| Total | 202.8 kg per month / 2.43 t per year |
| Annual energy cost | $1,764 |
| Cost per tonne | $725 |
Worked example: changing the grid and the renewable share
Selecting France instead of the UK cuts the electricity line to 18.2 kg and the total to 139.4 kg a month (1.67 tonnes a year), while the energy bill is unchanged at $1,764. Selecting Australia with a 50% renewable share gives 89.3 kg of electricity and 210.4 kg in total, or 2.53 tonnes a year. A home with 250 kWh of electricity on the US average factor, no gas and 100% renewable electricity records 0.0 kg and an annual cost of $480 at $0.16 per kWh.
| Setting | Electricity kg/month | Total kg/month | Tonnes/year |
|---|---|---|---|
| UK, 0% renewable | 81.6 | 202.8 | 2.43 |
| France, 0% renewable | 18.2 | 139.4 | 1.67 |
| Australia, 50% renewable | 89.3 | 210.4 | 2.53 |
| US-avg, 100% renewable, no gas (250 kWh) | 0.0 | 0.0 | 0.00 |
What to take from it
The grid factor is often the largest swing, so the country setting matters more than small changes in usage. The renewable share changes only the electricity part, and a household that heats with gas will see most of its remaining emissions in the gas line. Compare settings one at a time to see which lever moves your total.
Limits
The factors are single averages with no seasonal or hourly variation. The tool does not read meter data, does not handle other fuels, and does not turn the result into an environmental claim beyond the arithmetic.
Learn more from an authoritative source:
WikipediaWater Usage Calculator
Calculate your household's daily water consumption in litres and your estimated annual water bill.
Recycling Impact Calculator
See the environmental savings from recycling household materials including CO₂, energy, and water.
Carbon Offset Calculator
Calculate the cost to offset a given carbon footprint through different verified offset programmes.
Renewable Energy Payback Calculator
Calculate the payback period, 25-year savings, and ROI for home solar panels or a small wind turbine.
Carbon Footprint Calculator
Calculate your personal annual carbon footprint from flights, driving, diet, and home energy.
Results are estimates for informational purposes only and do not constitute professional financial, medical, legal, or technical advice. Read full disclaimer →