Example 1
4,265 kg
A year with 12,000 km by car, 4,000 km in the air and 2,500 kWh. About 203 trees at 21 kg.
Carbon footprint calculator
You add car, flight and power into one footprint. 12,000 km, 4,000 km of flights and 2,500 kWh at 0.17 / 0.15 / 0.65 give 4,265 kg. Trees and offset price use the factors you type.
This is not a full emissions inventory and not a credit. Home energy: home CO₂. Diet: diet gas. Trees: tree sequestration.
Result
Car km, flight km and kWh. The result will show here.
How it works
Footprint = car km × 0.17 + flight km × 0.15 + kWh × 0.65, or your factors. 12,000, 4,000 and 2,500 give 2,040 + 600 + 1,625 = 4,265 kg. Trees = 4,265 / 21 ≈ 203. Offset at 40 per tonne is 170.60. 8,000, 0 and 1,800 give 2,530 kg. 20,000, 12,000 and 4,000 give 7,800 kg.
Kilometers and kilowatt-hours cannot be negative. Empty factors insert 0.17 / 0.15 / 0.65, 21 kg per tree, 40 per tonne and an 8 t average. Zero flight kilometers are fine: that term simply drops out.
You add car, flight and power. A home footprint counts power, gas and heat separately. Tree sequestration counts one tree, not this sum. Flight and RF is another sketch of a trip.
Offset price is optional. An empty field inserts 40 per tonne. 4.265 × 40 ≈ 170.60. That is not a credit bought on an exchange and not a certificate. The tree tile is a sketch at your kg per tree, not a planting order. The “Versus country average” tile uses words: X t below or above the average you typed. At 8 t and 4.265 t that is about 3.74 t below.
The result is in kilograms, to one decimal. Type 12000, not 12 000. A decimal in 0.17 works in a factor field.
The example button fills car km, flight km and kWh. It leaves factors empty, so the defaults apply. The result shows the footprint, trees, offset cost and the gap versus the average.
How to use
- Type 12000 car km, 4000 flight km and 2500 kWh. Zeros in flight are allowed.
- Leave factors empty if you want 0.17 / 0.15 / 0.65, 21 kg and 40 per tonne.
- Click Calculate. You get 4,265 kg and about 203 trees at 21 kg.
- 8000, 0 and 1800 give 2,530 kg. 20000, 12000 and 4000 give 7,800 kg.
- Change the country average when 8 t does not fit. That is your comparison, not an official table.
Formula
kg = car_km × f_car + flight_km × f_flight + kWh × f_grid. trees = kg / kg_per_tree. offset = kg/1000 × price.
Car, flight, power and offset
12,000 km, 4,000 km of flights and 2,500 kWh give 4,265 kg at 0.17 / 0.15 / 0.65.
- Car
- Km × 0.17. 12,000 give 2,040 kg. Type another factor yourself.
- Flight
- Km × 0.15. 4,000 give 600 kg. A sketch, not a full life-cycle of the trip.
- Offset
- Tonnes × price. 4.265 × 40 ≈ 170.60. Not an exchange credit.
- Versus average
- Country average minus your footprint in tonnes. At 8 t and 4.265 t the tile shows about 3.74 t below, not −3.74 t.
Worked examples
Example 2
2,530 kg
A shorter year: 8,000 km by car, no flight, 1,800 kWh. Wheels and power only.
Example 3
7,800 kg
A long car year and a long-haul flight: 20,000 km, 12,000 km in the air, 4,000 kWh.
Suggested uses
- You add up a year: 12,000 km by car, 4,000 km of flights and 2,500 kWh, before you buy an offset without numbers. That is 4,265 kg.
- Without the flight it is 2,530 kg. The gap is roughly one trip in this sketch.
Frequently asked questions
How much from 12,000 km, 4,000 km of flights and 2,500 kWh?
4,265 kg. Car 2,040, flight 600, power 1,625. At 21 kg per tree that is about 203 trees. Offset at 40 per tonne is 170.60.
What does versus country average mean?
It is the average you typed (8 t by default) minus your footprint in tonnes. 4,265 kg is 4.265 t, so the tile shows about 3.74 t below. If you sit over the average, it says X t above. On the average: “on that average”. That is your comparison, not an official table.
What about 8,000, 0 and 1,800?
2,530 kg. Car and power only: 8,000 × 0.17 = 1,360 and 1,800 × 0.65 = 1,170.
What about 20,000, 12,000 and 4,000?
7,800 kg. A longer car year and a long-haul flight almost double the first example.
Is 4,265 kg a certificate?
No. It is three products added up. A CO2 credit and a full emissions inventory sit outside this page.
Where do 0.17 and 0.15 come from?
They are default sketches that keep the field from sitting empty. Type your own when you have a car reading or a flight factor. This is not a full life-cycle assessment.
Is 21 kg per tree fixed?
No. An empty field inserts 21. Another number changes the tree ratio. The tree tile is a sketch, not a planting order. One tree does not cancel 4,265 kg a year in every climate.
What does the 8 t average mean?
Your comparison assumption. 4,265 kg is 4.265 t, so versus 8 t you sit about 3.74 t below that average.
Do empty factors break the result?
No. Empty 0.17 / 0.15 / 0.65, 21 kg, 40 per tonne and 8 t fill themselves. Type only what you want to change.
Does a comma in 12.5 work?
Yes. 12.5 and 12,5 are read the same way.
Knowledge sources
The factors on the card are a sketch. Below are EPA emissions terms, not a national inventory.
Page updated in 2026.